CN1864428B - Apparatus and method for communication system and monitoring message - Google Patents

Abstract

Embodiments disclosed herein address a need in the art for efficiently managing authorization, acknowledgment, and rate control channels. In one aspect, a list associated with a first communication station is generated or stored, the list comprising zero or more identifiers, each identifier identifying one of a plurality of second communication stations for transmitting messages to the first communication station. In another aspect, a list set of one or more first communication stations is generated or stored. In another aspect, the message may be an acknowledgment, a rate control command, or an authorization. In another aspect, a message is generated that includes one or more identifiers from the list. Various other aspects may also be provided. These aspects have the advantage of reducing overhead in managing authorization, acknowledgment, and rate control messages for one or more remote communication stations.

Description

Apparatus and method for communication system and monitoring messages

Priority claims under 35 U.S.C. §119

This patent application claims priority to Provisional Patent Application Serial No. 60/493,046, filed August 5, 2003, entitled "Reverse Link Rate Control for CDMA2000RevD," and filed August 18, 2003, entitled " Priority to Provisional Patent Application No. 60/496,297 for Reverse Link Rate Control for CDMA 2000 Rev D.

background

technical field

The present invention relates generally to wireless communications, and more particularly to active pilot sets for grant, acknowledgment, and rate control channels.

Background technique

Wireless communication systems are widely used to provide various types of communication such as voice and data. A typical wireless data system or network provides multi-user access to one or more shared resources. A system may use multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM) and others.

Examples of wireless networks include cellular-based data systems. The following are a few such examples: (1) "TIA/EIA-95-B Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular Systems" (IS-95 standard), (2) The organization of "3rd Generation Partnership Project" (3GPP) proposed and included in the collection of documents including documents Nos. (3) proposed by an organization named "3rd Generation Partnership Project 2" (3GPP2) and included in "TR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum System" (IS-2000 Standard ), (4) High Data Rate (HDR) systems following the TIA/EIA/IS-856 standard (IS-856 standard), and (5) IS including C.S0001.C to C.S0006.C Amendment C of the -2000 standard and related documents (including the subsequent Amendment D submission), known as the 1xEV-DV proposal.

In an example system of Revision D of the IS-2000 standard (currently under development), the transmission of the mobile station on the reverse link is controlled by the base station. The base station can determine the maximum rate or traffic-to-pilot ratio (TPR) at which the mobile station is allowed to transmit. Two control mechanisms are currently proposed: authorization-based and rate-based control.

In authorization-based control, the mobile station feeds back information such as the mobile station's transmission capability, data buffer size, and quality of service (QoS) level to the base station. The base station monitors the feedback from multiple mobile stations and decides which transmissions to allow and the corresponding maximum rate allowed for each. These decisions are communicated to the mobile station via authorization messages.

In rate-control-based control, the base station adjusts the rate of the mobile station within a limited range (eg, up, unchanged, down). Adjustment commands are communicated to mobile stations using simple binary rate control bits or multi-valued indicators.

In buffer full conditions, ie, when active mobile stations have large amounts of data, grant-based and rate-control techniques perform roughly the same. Ignoring the overhead problem, the authorization method can better control the mobile station in the actual traffic mode. Ignoring overhead issues, the authorization method can better control different QoS flows. Two types of rate control can be differentiated, including a dedicated rate control method that gives each mobile a separate bit and a common rate control method that uses one bit each. Putting these two methods into different mixes can assign multiple mobile stations to one rate control bit. A common rate control method may require less overhead. However, the shared rate control method provides less control to the mobile station when compared to more dedicated control schemes. As the number of mobile stations transmitting at any one time decreases, then the shared rate control method approaches the dedicated rate control method.

Grant-based technology can quickly change the transmission rate of the mobile station. However, pure grant-based techniques suffer from the need for higher overhead if there are continuous rate changes. Similarly, pure rate control techniques suffer from slower ramp-up times and equal or higher overhead during ramp-up times.

Neither approach provides reduced overhead and large or fast rate adjustments. An example of a method to satisfy this need is contained in Application No. XX/XXX,XXX (Attorney Docket No. 030525 ) published in U.S. Patent Application No. Furthermore, it is desirable to reduce the number of control channels while maintaining the desired error probability of the associated commands on the control channels. There is a need in the art for systems that provide the ability to control the rate (or allocate resources for) individual mobile stations as well as groups of mobile stations without excessively increasing the number of channels. In addition, there is a need to be able to accommodate error probabilities for various rate control or acknowledgment commands. An example of a method to meet this need is in U.S. Ser. No. XX/XXX,XXX, filed February 17, 2004, entitled "Extended Acknowledgment and Rate Control Channel," assigned to the assignee of the present invention (Attorney for the Record No. 030560) patent application disclosed.

While the flexibility of control provided by combined grant, rate control and acknowledgment transmissions allows for adaptive allocation of system resources, it is also desirable to control the role of individual base stations in the system with regard to which signals a base station transmits and which allocation control a base station can participate in. Schemes that provide controlled ad-hoc signaling require high signaling overhead. The failure of some base station-wide control can also cause system performance problems if a grant or rate control command is issued, with an insignificant impact on the sending base station. There is thus a need in the art to efficiently manage grant, acknowledgment and rate control channels.

Contents of the invention

Embodiments disclosed herein address the need in the art to efficiently manage grant, acknowledgment, and rate control channels. In an aspect, a list is generated or stored associated with a first station, the list including zero or more identifiers, each identifier identifying one of a plurality of second stations for sending messages to the first station . In another aspect, a list set of one or more first stations is generated or stored. In another aspect, the message may be an acknowledgment, a rate control command, or a grant. In another aspect, a message is generated that includes the one or more identifiers in the list. A number of other aspects are also presented. These aspects have the advantage of reducing overhead while managing authorization, acknowledgment and rate control messaging for one or more telecommunication stations.

The present invention provides an apparatus for monitoring messages comprising: a processor for generating a list comprising zero or more identifiers, the list being associated with a first station, each identifier identifying a one of a plurality of second communication stations for transmitting the first message to the first communication station; and a transmitter for transmitting the second message to the first communication station, wherein the processor also generates a sequence comprising zero or A second message of more identifiers; the second message instructing the first station to delete the identifier from a list of identifiers stored within the first station.

The invention also provides an apparatus for monitoring messages, comprising: a processor for generating a list comprising zero or more identifiers, the list being associated with a first communication station, each identifier identifying a user one of a plurality of second communication stations for transmitting a first message to the first communication station; a transmitter for transmitting a second message to the first communication station, wherein the processor further generates a sequence comprising zero or A second message of more identifiers; wherein the second message instructs the first station to add the identifier to a list of identifiers stored within the first station.

The present invention also provides a method for monitoring messages, comprising: generating a list comprising zero or more identifiers, the list being associated with a first communication station, each identifier identifying an one of a plurality of second communication stations to which the station sends the first message; and transmits a second message to the first communication station, the second message including zero or more identifiers in the list; wherein the second message indicates the first The station deletes the identifier from the list of identifiers stored in the first station.

The present invention also provides a method for monitoring messages, comprising: generating a list comprising zero or more identifiers, the list being associated with a first communication station, each identifier identifying an one of a plurality of second communication stations to which the station sends the first message; and transmits a second message to the first communication station, the second message including zero or more identifiers in the list; wherein the second message indicates the first communication The station adds the identifier to a list of identifiers stored in the first station.

Description of drawings

FIG. 1 is a generalized block diagram of a wireless communication system capable of supporting multiple users;

Figure 2 depicts an example mobile station and base station configured in a system suitable for data communications;

3 is a block diagram of a wireless communication device such as a mobile station or a base station;

Figure 4 depicts an illustrative embodiment of data and control signals for reverse link data communications;

Figure 5 is an illustrative acknowledgment channel;

Figure 6 is an illustrative rate control channel;

7 is an example methodology that may be implemented within a base station to allocate capacity in response to requests and transmissions from one or more mobile stations.

Figure 8 is an example method of generating authorization, confirmation, and rate control commands;

Figure 9 is an example method for a mobile station and monitors and responds to grant, acknowledgment and rate control commands;

FIG. 10 depicts synchronization of an example embodiment with combined acknowledgment and rate control channels;

FIG. 11 depicts synchronization of an example embodiment with combined acknowledgment and rate control channels and new grants;

FIG. 12 depicts synchronization of an example embodiment with combined acknowledgments and rate control channels without grants;

FIG. 13 depicts an example embodiment of a system including dedicated rate control signals and shared rate control signals;

Figure 14 depicts an embodiment of a system comprising a forward-spread acknowledgment channel;

Figure 15 depicts an example constellation diagram suitable for implementation on an extended acknowledgment channel;

Figure 16 depicts another constellation diagram suitable for implementation on an extended acknowledgment channel;

Figure 17 depicts a three-dimensional example constellation diagram suitable for implementation on an extended acknowledgment channel;

Figure 18 depicts an embodiment of a method for processing received transmissions including acknowledgments and rate control;

Figure 19 depicts an embodiment of a method for responding to shared and dedicated rate control;

Figure 20 depicts another embodiment of a method for processing received transmissions including acknowledgments and rate control;

Figure 21 depicts a method for receiving and responding to a forward extended acknowledgment channel;

Figure 22 is a generalized block diagram of a wireless communication system including an extended active pilot set;

Figure 23 is an example extended effective pilot set;

Figures 24-26 are examples of further example extended effective pilot sets;

Figure 27 depicts an example embodiment of a method for generating an extended effective pilot set;

Figure 28 depicts an example embodiment of a method for transmission in accordance with an extended active pilot set;

Figure 29 depicts an example embodiment of a method for communicating with an extended active pilot set within a mobile station; and

30 depicts an example message suitable for communicating changes to an expanded active pilot set.

Detailed ways

The example embodiments detailed below provide for sharing resources as shared by one or more mobile stations in a communication system by conveniently controlling or adjusting one or more data rates associated with various acknowledgment messages communicated in the system distribute.

Techniques and advantages thereof are disclosed herein to combine the use of grant channels, acknowledgment channels, and rate control channels to provide a combination of grant-based scheduling and rate-control scheduling. Various embodiments have one or more of the following advantages: fast increase of mobile station transmission rate, fast mobile station stop transmission, low overhead adjustment of mobile station rate, low overhead mobile station transmission acknowledgment, overall low overhead, and or Quality of Service (QoS) control of flows originating from multiple mobile stations.

The rate control channel is combined with the acknowledgment channel using a constellation of points for various command pairs, resulting in a reduction in control channels. Additionally, a constellation diagram can be formed to provide a desired error probability for each associated command. Dedicated rate control signals can be used with common rate control signals. The use of one or more dedicated rate control channels together with one or more common rate control channels allows specific rate control for a single mobile station and the ability to control a larger group of mobile stations with less overhead. Various other advantages are detailed below.

One or more illustrative embodiments described herein are set forth in the context of a digital wireless data communication system. Although advantageous for use in this context, different embodiments of the invention may also be embodied in different environments or configurations. In general, the various systems described herein can be formed using software-controlled processors, integrated circuits, or discrete logic. Data, instructions, commands, information, signals, symbols, and chips that may be referenced in an application are conveniently represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or combinations thereof. Furthermore, the blocks shown in each block diagram may represent hardware or method steps.

More specifically, various embodiments of the present invention may be included in wireless communication systems operating in accordance with communication standards outlined and disclosed in various standards published by the Telecommunications Industry Association (TIA) and other standards organizations. These standards include the TIA/EIA-95 standard, the TIA/EIA-IS-2000 standard, the IMT-2000 standard, the UMTS and WCDMA standards, the GSM standard, all of which are incorporated herein by reference. Copies of this standard may be obtained by writing to TIA, Standards and Technology Department, 2500 Wilson Boulevard, Arlington, VA 22201, United States of America. The standard commonly referred to herein as the UMTS standard can be obtained by contacting the 3GPP Support Office, 650 Route des Lucioles-Sophia Antipolis, Valbonne-France.

1 is a diagram of a wireless communication system 100 designed to support one or more CDMA standards and/or designs (e.g., W-CDMA standard, IS-95 standard, cdma2000 standard, HDR standard, 1xEV-DV system) . In another embodiment, system 100 may support any wireless standard or design in addition to CDMA systems. In the illustrative embodiment, system 100 is a 1xEV-DV system.

For simplicity, system 100 is illustrated as including three base stations 104 in communication with two mobile stations 106 . The base station and its coverage area are often collectively referred to as a "cell." In IS-95, cdma2000 or IxEV-DV systems, for example, a cell may consist of one or more parts. In the W-CDMA specification, each part of a base station and its coverage area is called a cell. As used herein, the term base station is used interchangeably with the terms access point or Node B. The term mobile station is used interchangeably with user equipment (UE), subscriber unit, subscriber station, access terminal, remote terminal, or other corresponding terms known in the art. The term mobile station includes fixed wireless installations.

According to currently implemented CDMA systems, each mobile station 106 can communicate with one (or possibly multiple) base stations 104 on the forward link at any time, and can communicate with the base station 104 on the forward link according to whether the mobile station is in soft handoff (soft handoff). One or more base stations communicate on the reverse link. The forward link (ie, downlink) refers to transmissions from base stations to mobile stations, and the reverse link (ie, uplink) refers to transmissions from mobile stations to base stations.

Although various embodiments described herein relate to providing reverse link or forward link signals to support reverse link transmissions, some of these embodiments are also well suited for reverse link Given the nature of the transmission, those skilled in the art will recognize that mobile stations and base stations may be configured to transmit data as described herein, and that aspects of the invention may also be applied in those cases. The word "illustrative" is used exclusively herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "illustrative" is not necessarily to be construed as advantageous over other embodiments.

1xEV-DV forward link data transmission

System 100, as described in the 1xEV-DV proposal, generally includes four types of forward link channels: overhead channels, dynamically variable IS-95 and IS-2000 channels, forward packet data channel (F-PDCH), and some free channel. Overhead channel assignments change slowly; for example, they may not change for several months. They usually change when the main network structure changes. Dynamically variable IS-95 and IS-2000 channels are allocated or used for IS-95 or IS-2000 versions 0 to B voice and packet traffic on a per-call basis. Normally, after overhead channels and dynamically variable channels have been allocated, the remaining effective base station power will be allocated to F-PDCH for remaining data traffic.

Similar to the traffic channel of the IS-856 standard, the F-PDCH is used to transmit data to one or two users in each cell at the highest supported data rate at a time. In IS-856, the full power of the base station and the full headroom of the Walsh function are available when transmitting data to the mobile station. However, in the 1xEV-DV system, some base station power and some Walsh functions are allocated to overhead channels and existing IS-95 and cdma2000 services. Supportable data rates depend primarily on the available power and Walsh coding after the power and Walsh coding that have been allocated for the overhead, IS-95 and IS-200 channels. Data transmitted on the F-PDCH is distributed using one or more Walsh codes.

In a 1xEV-DV system, the base station typically transmits to one mobile station on the F-PDCH at a time, although many users may be using packet traffic within the cell. (Transmissions to both users can also be scheduled by scheduling transmissions to both users, with appropriate allocation of power and Walsh channels to each user.) A mobile station is selected for forward link transmission according to some scheduling algorithm.

In systems similar to IS-856 or 1xEV-DV, the scheduling is based in part on channel quality feedback from the mobile stations being served. For example, in IS-856, the mobile station estimates the quality of the forward link and calculates the transmission rate expected to be maintained for the existing conditions. The desired rate from each mobile station is transmitted to the base station. For example, the scheduling algorithm may select mobile stations for transmission that support relatively high transmission rates to more efficiently use the shared communication channel. As another example, in a 1xEV-DV system, each mobile station transmits a carrier-to-interference (C/I) estimate on a reverse channel quality indicator channel (R-CQICH) as a channel quality estimate. The scheduling algorithm is used to determine the mobile station to be selected for transmission, and select the appropriate rate and transmission format according to the channel quality.

As noted above, the wireless communication system 100 may support multiple users sharing communication resources simultaneously, such as an IS-95 system, may allocate all communication resources to one user at a time, such as an IS-856 system, or may allocate communication resources to allow both access type. A 1xEV-DV system is an example of a system that divides communication resources between two access types and allocates them dynamically according to user needs. An illustrative forward-link example has just been illustrated. A number of illustrative reverse-link embodiments are described in further detail below.

2 depicts an example mobile station 106 and base station 104 configured within a system 100 suitable for data communications. Base station 104 and mobile station 106 are shown communicating on forward and reverse links. Mobile station 106 receives forward link signals within receive subsystem 220 . The base station 104 that communicates the forward data and control channels detailed below may be referred to herein as the serving base station for the mobile station 106 . An example receiving subsystem is described in further detail below with reference to FIG. 3 . A carrier-to-interference (C/I) estimate is generated within the mobile station 106 for the forward link signal received from the serving base station. The C/I measurement is an example of a channel quality metric used for channel estimation, other channel quality metrics may be used in other embodiments. The C/I measurements are communicated to a transmission subsystem 210 within the base station 104, an example of which is further described below with reference to FIG. 3 .

Transmission subsystem 210 transmits the C/I estimate on the reverse link, which is transmitted to the serving base station. Note that in the context of a soft handover procedure, as is known in the art, the reverse link signal transmitted from the mobile station may be received by one or more base stations other than the serving base station, referred to herein as non-serving base stations. Receive subsystem 230 in base station 104 receives C/I information from mobile station 106 .

A scheduler 240 within the base station 104 is used to determine if and how data should be transmitted to one or more mobile stations within the coverage area of the serving cell. Any type of scheduling algorithm can be used within the scope of the present invention. An example is disclosed in patent application Ser. No. 08/798,951, filed February 11, 1997, entitled "Method and Apparatus for Forward Link Rate Scheduling," assigned to the assignee of the present invention.

In an example IxEV-DV embodiment, a mobile station is selected for forward link transmission when a C/I measurement received from the mobile station indicates that data can be transmitted at a particular rate. In terms of system capacity, it is advantageous to select target mobile stations such that shared communication resources are always used at their maximum supportable rate. Thus, the typical target mobile station selected may be the one with the largest reported C/I. Other factors may also be included in scheduling decisions. For example, minimum quality of service guarantees may be applied to individual users. A mobile station with a relatively lower reported C/I may be selected for transmission to maintain a minimum data transfer rate to that user. The mobile station that does not have the largest reported C/I may be selected for transmission to maintain a certain fairness criterion among all users.

In the example IxEV-DV system, the scheduler 240 determines to which mobile station to transmit, and also determines the data rate, modulation format, and power level for the transmission. For example, in another embodiment, such as IS-856 system, the supportable rate/modulation format decision can be made at the mobile station based on the channel quality measured at the mobile station, and the transmission format can replace C/I The measurements are transmitted to the serving base station. Those skilled in the art will recognize that a large number of supportable combinations of rates, modulation formats, power levels, etc. can be used within the scope of the present invention. Furthermore, while in many of the embodiments described herein the scheduling tasks are performed in the base station, in other embodiments some or all of the scheduling processing may occur in the mobile station.

Scheduler 240 instructs transmission subsystem 250 to transmit to selected mobile stations on the forward link using the selected rate, modulation format, power class, etc.

In an example embodiment, messages on a control channel or F-PDCCH are transmitted with data on a data channel or F-PDCH. The control channel can be used to identify mobile stations receiving data on the F-PDCH, and can identify other communication parameters useful during a communication session. When the F-PDCCH indicates that the mobile station is a transmission target, the mobile station shall receive and demodulate data from the F-PDCH. Upon receipt of this data, the mobile station responds on the reverse link with a message indicating the success or failure of the transmission. As known in the art, retransmission techniques are widely used in data communication systems.

A mobile station can communicate with more than one base station, a so-called soft handover procedure. Soft handover may include multiple parts of a base station (or a base transceiver subsystem (BTS)), considered softer handover, may also include parts of multiple BTSs. The base station part during soft handover is usually stored in the active pilot set of the mobile station. In a synchronous shared communication resource system, such as IS-95, IS-2000 or the corresponding portion of a 1xEV-DV system, the mobile station may combine forward link signals transmitted from all portions of the active pilot set. In a data-only system (data-only system), such as IS-856 or the corresponding part of the 1xEV-DV system, the mobile station receives the forward link data signal from a base station in the active pilot set, the serving base station (according to The mobile station selection algorithm is determined, as those described in the C.S0002.C standard). Other forward link signals, examples of which are detailed further below, may also be received from non-serving base stations.

The reverse link signal from the mobile station can be received at multiple base stations, and the quality of the reverse link is generally maintained for the base stations in the active pilot set. Reverse link signals received at multiple base stations may be combined. Typically, soft combining reverse link signals from dispersed base stations would require a large network communication bandwidth and little delay, so the example systems listed above do not support this kind of soft combining. During softer handover, reverse link signals received at multiple parts in a single BTS can be combined without network signaling. Although any type of reverse link signal combination may be used within the scope of the present invention, in the example system described above, reverse link power control maintains quality such that reverse link frames are successfully decoded at one BTS (handover diversity )

Reverse link data transmission may also be performed within system 100 . The receive and transmit subsystems 210-230 and 250 described above may be used to send control signals on the forward link to indicate data transmission on the reverse link. Mobile station 106 may also transmit control information on the reverse link. Each mobile station 106 in communication with one or more base stations 104 has access to a shared communication resource (i.e., a variable allocation of reverse link channels, as in 1xEV-DV, or a fixed allocation, as in IS-856), In response to various access control and rate control techniques, examples of which are detailed below. A scheduler 240 may be employed to determine allocation of reverse link resources. Example control and data signals for reverse link data communications are detailed below.

Example Base Station and Mobile Station Embodiments

FIG. 3 is a block diagram of a wireless communication device, such as mobile station 106 or base station 104 . The blocks depicted in this example embodiment are generally a subset of elements included in a base station 104 or mobile station 106 . Those skilled in the art can readily adapt the embodiment shown in Figure 3 to any number of base station or mobile station configurations.

Signals are received at antenna 310 and transmitted to receiver 320 . Receiver 320 performs processing in accordance with one or more wireless system standards, such as those listed above. Receiver 320 performs various processing such as radio frequency (RF) to baseband conversion, amplification, analog-to-digital conversion, filtering, and the like. Various techniques for receiving are known in the art. Although a separate channel quality estimator 335 is shown for clarity of the discussion detailed below, the receiver 320 may be used to measure the channel quality of the forward or reverse link when the device is a mobile station or a base station, respectively.

Signals received from receiver 320 are demodulated in demodulator 325 in accordance with one or more communication standards. In an example embodiment, a demodulator capable of demodulating 1xEV-DV signals is used. In other embodiments, other standards may be supported, and embodiments may support multiple communication formats. Demodulator 330 may perform RAKE reception, equalization, combining, deinterleaving, decoding, and various other functions required by the received signal format. Various demodulation techniques are known in the art. In base station 104, demodulator 325 will demodulate in accordance with the reverse link. In mobile station 106, demodulator 325 will demodulate in accordance with the forward link. The data and control channels described herein are examples of channels that are received and demodulated in receiver 320 and demodulator 325 . Demodulation of the forward data channel will occur in accordance with signaling on the control channel as described above.

Message decoder 330 receives the demodulated data and extracts signals or messages directed to mobile station 106 or base station 104 on the forward or reverse link, respectively. The message decoder 330 decodes various messages used to establish, hold and release calls (including voice or data sessions) on the system. The messages may include channel quality indications such as C/I measurements, power control messages or control channel messages for demodulating the forward data channel. Various types of control messages can be decoded within base station 104 or mobile station 106 when transmitted on the reverse or forward link, respectively. For example, the following describes the generation of a request message and a grant message for scheduling reverse link data transmission in a mobile station or a base station, respectively. Other different message types are specified by various communication standards that are known in the art and can be supported. This message may be passed to processor 350 for subsequent processing. Some or all of the functionality of message decoder 330 may be performed in processor 350, although shown as separate blocks for clarity of illustration. Additionally, demodulator 325 may decode certain information and send it directly to processor 350 (such as ACK/NAK or separate bit messages for power control up/down commands as examples). The various signals and messages for use within the embodiments disclosed herein are described in further detail below.

A channel quality estimator 335 is coupled to the receiver 320 and is used to generate various power level estimates used in the processes described herein as well as various other processes used in communications, such as demodulation. In mobile station 106, C/I measurements may be made. Additionally, measurements of any signal or channel used in the system may be measured in the channel quality estimator 335 of a given embodiment. In base station 104 or mobile station 106, a signal strength estimate, such as received pilot power, can be generated. Channel quality estimator 335 is shown as a separate block for clarity of illustration only. Typically this block may be included within another block such as receiver 320 or demodulator 325 . Various types of signal strength estimates may be generated depending on the type of signal or system being estimated. In general, any type of channel quality metric estimation block can be used in place of channel quality estimator 335 within the scope of the invention. In base station 104, the channel quality estimate is communicated to processor 350 for use in scheduling or determining reverse link quality, as further described below. The channel quality estimate can be used to determine whether an up or down power control command is needed to drive forward or reverse link power to a desired setpoint. The desired set point may be determined by an outer loop power control mechanism.

Signals are transmitted through antenna 310 . Signals to be transmitted are programmed within transmitter 370 in accordance with one or more wireless system standards as listed above. Examples of components that may be included in transmitter 370 are amplifiers, filters, digital-to-analog (D/A) converters, radio frequency (RF) converters, and the like. Data for transmission is provided through modulator 365 to transmitter 370 . Data and control channels can be formatted for transmission in a variety of formats. Data for transmission on the forward link data channel may be formatted in modulator 365 according to a rate and modulation format specified by a scheduling algorithm consistent with C/I or other channel quality measurements. A scheduler such as scheduler 240 as described above may reside in processor 350 . Similarly, transmitter 370 may be instructed to transmit at a power level in accordance with a scheduling algorithm. Examples of elements that may be included in modulator 365 include various types of encoders, interleavers, spreaders, and modulators. The following description includes a reverse link design of an example modulation format and access control, which is applicable to a 1xEV-DV system.

Message generator 360 may be used to prepare various types of messages, as described above. For example, a C/I message may be generated within the mobile station for transmission on the reverse link. Various types of control messages can be generated in base station 104 or mobile station 106 for transmission on the forward or reverse link, respectively. For example, the following describes the request message and the grant message generated in the mobile station and the base station, respectively, for scheduling reverse link data transmission.

Data received and demodulated in demodulator 325 may be communicated to processor 350 for voice or data communications, among various other elements. Similar data for transmission may be directed from processor 350 to modulator 365 and transmitter 370 . For example, various data applications may be present on processor 350 or other processors included in wireless communication device 104 or 106 (not shown). Base station 104 may be connected to one or more external networks, such as the Internet (not shown), through other not-shown devices. Mobile station 106 may include a link to an external device such as a laptop computer (not shown).

Processor 350 may be a general purpose microprocessor, a digital signal processor (DSP), or a special purpose processor. Processor 350 may perform some or all of the functions of receiver 320, demodulator 325, message decoder 330, channel quality estimator 335, message generator 360, modulator 365, or transmitter 370, as well as any required by the wireless communication device. other processing. Processor 350 may be coupled with dedicated hardware to assist in these tasks (details not shown). Data or voice applications may be external, such as an externally connected laptop or connection to a network, may also run on an additional processor in wireless communication device 104 or 106 (not shown), or may run on processor 350 run on itself. Processor 350 is coupled to memory 355 for storing data and storing instructions for performing the various procedures and methods described herein. Those skilled in the art will recognize that memory 355 may consist of one or more different types of storage elements embedded in whole or in part within processor 350 .

A typical data communication system may include one or more channels of different types. More specifically, there are typically one or more data channels configured. Typically one or more control channels may also be configured, although in-band control signaling can be included on data channels. For example, in a 1xEV-DV system, a Forward Packet Data Control Channel (F-PDCCH) and a Forward Packet Data Channel (F-PDCH) are defined for transmission of control and data on the forward link, respectively. Various example channels for reverse link data transmission are described below.

1xEV-DV Reverse Link Design Considerations

In this section, various factors considered in the design of an example embodiment of a reverse link of a wireless communication system are illustrated. In various embodiments detailed further in the following sections, signals, parameters and procedures related to the IxEV-DV standard are used. This standard is for illustration only, as the various aspects and combinations described herein may be used in any number of communication systems within the scope of the invention. This section serves as a partial summary, although not exhaustive, of various aspects of the invention. Example embodiments are described in further detail in subsequent sections below, where additional aspects are illustrated.

In many cases, reverse link capacity is limited by interference. The base station allocates active reverse link communication resources to mobile stations to efficiently utilize maximum throughput in accordance with quality of service (QoS) requirements of various mobile stations.

Maximizing the use of reverse link communication resources includes several factors. One factor to consider is the mix of scheduled reverse link transmissions originating from various mobile stations, each of which may experience different channel qualities at any given time. In order to increase the overall throughput (total data transmitted by all mobile stations within a cell), it is desirable that whenever reverse link data is sent, the entire reverse link can be fully utilized. To meet effective capacity, mobile stations may be granted access at the highest rate they can support, and additional mobile stations may be granted access until capacity is reached. One factor that a base station may consider when deciding which mobile station to schedule is the maximum rate each mobile station can support and the amount of data each mobile station must transmit. Mobile stations with higher throughput may be selected over other mobile stations whose channels do not support higher throughput.

Another factor to consider is the quality of service required by each mobile station. While delaying access to a mobile may be allowed in anticipation of channel improvement, rather than selecting a more suitable mobile, a single page requires suboptimal mobiles to be granted access to meet minimum quality of service guarantees. As such, the scheduled data throughput may not be an absolute maximum, but it is maximized to a considerable extent taking into account channel conditions, effective mobile station transmit power, and service requirements. Any configuration that reduces the signal-to-noise ratio for selected combinations is desired.

Various scheduling mechanisms are described below to allow mobile stations to transmit data on the reverse link. One type of reverse link transmission involves a mobile station requesting a transmission on the reverse link. The base station makes a determination whether there are resources available to satisfy the request. Authorization can be made to allow the transfer. The signaling connection between the mobile station and the base station introduces a delay before reverse link data can be transmitted. This delay is acceptable for certain classes of reverse link data. Other classes may be more sensitive to delay, and other techniques for reverse link transmission that reduce delay are detailed below.

Additionally, reverse link resources are consumed to issue a request for transmission, and forward link resources are consumed to respond to the request, ie, issue a grant. When the mobile station's channel quality is low, ie, poor geometry or deep fading, the power required to reach the mobile station on the forward link may be relatively high. Various techniques are detailed below to reduce the number of requests and grants and required transmit power required for reverse link data transmission.

To avoid delays introduced by request/grant signaling connections, and to reserve the forward and reverse link resources needed to support it, an autonomous reverse link transmission mode is supported. Mobile stations can transmit data at a limited rate on the reverse link without requesting or waiting for grants.

It is also desirable that the transmission rate of a mobile station, either under a grant or autonomously, can be changed without the overhead of a grant. To this end, rate control commands can be implemented with autonomous and request/grant based scheduling. For example, the set of commands may include commands to increase, decrease, and keep the current rate of transmission unchanged. The rate control commands can be addressed to individual mobile stations or groups of mobile stations. Various example rate control commands, channels and signals are detailed further below.

The base station allocates a portion of the reverse link capacity to one or more mobile stations. Mobile stations authorized to access are provided with maximum power levels. In the example embodiment described herein, reverse link resources are allocated using a traffic-to-pilot (T/P) ratio. Since the pilot signal for each mobile station is adaptively controlled through power control, specifying the T/P ratio indicates the available power for transmitting data on the reverse link. A base station may issue specific grants to one or more mobile stations, indicating a specific T/P ratio for each mobile station. The base station may also issue a pooling grant to the remaining mobile stations that have requested access, indicating the maximum T/P value that the remaining mobile stations are allowed to transmit. Autonomous and scheduled transmissions, individual and shared grants, and rate control are further detailed below.

A variety of scheduling algorithms are known in the art, and many more still need to be developed, which are capable of assigning grants based on the number of registered mobile stations, the probability of a mobile station's autonomous transmission, the number and size of outstanding requests, The expected average response for , as well as any number of other factors, determine various specific and common T/P values for authorization and expected rate control commands. In one example, the selection is made based on quality of service (QoS) priorities, efficiency, and throughput achievable by the group of requesting mobile stations. An example scheduling technique is found in U.S. Patent No. 10/651,810, filed August 28, 2003, entitled "System and Method for a Time-Extended, Priority-Based Scheduler," assigned to the assignee of the present invention Open in application. Other references include U.S. Patent 5,914,950, entitled "Method and Apparatus for Reverse Link Rate Scheduling," and U.S. Patent 5,923,650, also entitled "Method and Apparatus for Reverse Link Rate Scheduling," both of which Assigned to the assignee of the present invention.

The mobile station can use one or more sub-packets to transmit data packets, where each sub-packet includes complete packet information (since multiple encodings or redundancy can be used in various sub-packets, the encoding of each sub-packet does not need to be the same). Retransmission techniques may be employed to ensure reliable transmission, such as automatic repeat request (ARQ). Thus, if the first subpacket is received without error (e.g. using CRC), an acknowledgment (ACK) is sent to the mobile station and no additional subpackets will be sent (considering that each subpacket includes the entire packet in one form or the other information). If the first subpacket was not received correctly, a negative acknowledgment (NAK) is sent to the mobile station and the second subpacket will be transmitted. The base station can combine the energies of the two sub-packets and try to decode it. This process can be repeated indefinitely, although usually a maximum number of subpackages can be specified. In the example embodiment described herein, up to four subpackets may be transmitted. In this way, as additional subpackets are received, the probability of correct reception increases. Detailed below are different methods of combining ARQ responses, rate control commands, and grants to provide a desired level of transmission rate flexibility with an acceptable level of overhead.

As mentioned above, a mobile station can trade latency for throughput to decide whether to use autonomous transmission with less latency to transmit data or request a higher rate switch and wait for a shared or specific grant. Additionally, for a given T/P, the mobile station can choose a data rate to accommodate delay or throughput. For example, a mobile station having relatively few bits for transmission may decide that a smaller delay is appropriate. For the available T/P (possibly the autonomous transmission maximum in this example, but could also be a specific or shared grant T/P), the mobile station can choose a rate and modulation format such that the base station correctly receives the first subpacket The probability is high. The mobile station will be able to transmit its data within one subpacket, although retransmissions can be made if necessary. In various example embodiments described herein, each subpacket is transmitted over a 5 ms period. Thus, in this example, the mobile station can make an immediate autonomous transmission that will likely be received at the base station after a 5 ms interval. Note that optionally, for a given T/P, the mobile station may use additional subpackets available to increase the amount of data transmitted. Therefore, a mobile station may choose to transmit autonomously to reduce the delay associated with requests and grants, and additionally trade throughput for a specific T/P to reduce the number of subpackets required (ie, delay). Even with the full number of subpackets selected, autonomous transfers will have less latency than requests and grants for relatively small data transfers. Those skilled in the art will recognize that as the amount of data to be transmitted increases, multiple packet transmissions are required, since the loss of requests and grants will eventually be offset by the increased throughput of the higher data rate of multiple packets, Overall latency can be reduced by switching to request and grant formats. This process is further detailed below with a set of examples of transmission rates and formats that can be associated with various T/P allocations.

reverse link data transfer

One goal of the reverse link design is to keep the rise over thermal (RoT) at the base station relatively constant as long as there is reverse link data to be transmitted. The transmission of the reverse link data channel can be handled in three different modes:

Autonomous Transport: This case is used for services that require lower latency. The mobile station is allowed to transmit immediately at a certain transmission rate determined by the serving base station (ie, the base station to which the mobile station directs its channel quality indicator (CQI)). The serving base station is also called a scheduling base station or an authorized base station. The maximum allowed transmission rate for autonomous transmission can be dynamically indicated by the serving base station according to system load, congestion, etc.

Scheduled transmission: The mobile station sends out estimates of its buffer size, available power, and possibly other parameters. The base station determines when the mobile station is allowed to transmit. The goal of the scheduler is to limit the number of simultaneous transmissions, thereby reducing interference between mobile stations. The scheduler can try to make mobile stations in the area between cells transmit at a lower rate to reduce interference to neighboring cells and to strictly control RoT to protect sound quality on R-FCH, DV feedback and acknowledgment on R-CQICH (R-ACKCH) and system stability.

Rate Control Transmission: Whether the mobile station transmits scheduled (ie, authorized) or autonomously, the base station can adjust the transmission rate through rate control commands. Example rate control commands include increasing, decreasing, or maintaining the current rate. Additional commands may be included to indicate how the rate shift is to be implemented (ie, the amount to increase or decrease). Rate control commands can be random or deterministic.

The various embodiments detailed herein include one or more features designed to increase the throughput, capacity, and overall system performance of the reverse link of a wireless communication system. For the sake of illustration only, the data part of the 1xEV-DV system is illustrated, in particular, the optimization of transmissions by different mobile stations on the Enhanced Reverse Supplementary Channel (R-ESCH) is illustrated. A number of forward and reverse link channels are detailed in this section for use in one or more example embodiments. These channels are generally a subset of the channels used in the communication system.

4 depicts an illustrative embodiment of data and control signals for reverse link data communications. Mobile station 106 is shown communicating on multiple channels, each channel being connected to one or more base stations 104A-104C. Base station 104A is labeled as a scheduling base station. The other base stations 104B and 104C are part of the active pilot set for the mobile station 106 . Four reverse link signals and four forward link signals are illustrated. They are described below.

R-REQCH

The reverse request channel (R-REQCH) is used by mobile stations to request reverse link transmission of data from a scheduling base station. In an example embodiment, the request is a request for transmission on the R-ESCH (further detailed below). In an example embodiment, the request on R-REQCH includes the T/P ratio the mobile station can support, variables according to changing channel conditions, and buffer size (ie, the amount of data waiting to be transmitted). The request may also specify the quality of service (QoS) of the data awaiting transmission. Note that a mobile station may have a separate QoS class assigned to the mobile station, or different QoS classes may be assigned for different types of service selections. Higher layer protocols may indicate QoS, or other desired parameters (such as latency or throughput requirements) for various data services. In another embodiment, the Reverse Dedicated Control Channel (R-DCCH) used in conjunction with other reverse link signals such as the Reverse Foundation Channel (R-FCH) (eg for voice services) may be used as a portability access ask. In general, an access request can be described as comprising a logical channel, ie, a reverse scheduling request channel (R-SRCH), that can be mapped on any existing physical channel like R-DCCH. Example embodiments are backward compatible with existing CDMA systems such as IS-2000 Revision C, and R-REQCH is a physical channel that can be used without R-FCH or R-DCCH. For clarity, the term R-REQCH is used to describe the access-request channel in the description of the embodiments herein, although those skilled in the art will easily extend its principles to any type of access-request system, whether the access-request channel is logical or physical of. R-REQCH can be turned off until the request is needed, thereby reducing interference and preserving system capacity.

In the example embodiment, the R-REQCH has 12 input bits consisting of: 4 bits specifying the maximum R-ESCH T/P ratio that the mobile station can support, 4 bits specifying the amount of data in the mobile station's buffer bits, and 4 bits specifying QoS. Those skilled in the art will appreciate that any number of bits and various other fields may be included in other embodiments.

F-GCH

A forward grant channel (F-GCH) is transmitted from the scheduling base station to the mobile station. F-GCH can consist of multiple channels. In an example embodiment, a common F-GCH channel is used to make common grants, while one or more individual F-GCH channels are used to make individual grants. Grants are made by the dispatching base station in response to one or more requests from one or more mobile stations on their respective R-REQCHs. A licensed channel may be denoted GCHx, where the subscript x designates the channel number. Channel number 0 may be used to designate a shared licensed channel. The subscript x ranges from 1 to N if there are N individual channels configured.

Individual grants may be made to one or more mobile stations, each of which allows the identified mobile station to transmit on the R-ESCH at a specified T/P rate or lower. Granting on the forward link naturally introduces the overhead of using some forward link capacity. A number of options for reducing authorization-related overhead are detailed herein, while other options will be apparent to those skilled in the art from the disclosure herein.

One consideration is that the mobile stations will be in situations where each mobile station experiences variations in channel quality. Thus, for example, a good geometry mobile station with good forward and reverse link channels requires relatively low power for the grant signal, and may utilize high data rates, and thus is suitable for separate grants. Mobile stations in poor geometry, or mobile stations experiencing deep fading, require more power to reliably receive individual grants. Such mobile stations may not be eligible for individual authorization. The forward link overhead for the shared grants for the mobile station detailed below is less.

In an example embodiment, some individual F-GCH channels are employed to provide a corresponding number of individual grants at a particular time. The F-GCH channel is code division multiplexed. This facilitates the ability to transmit each grant at just the power level needed to reach the particular intended mobile station. In another embodiment, a single individual grant channel may be used, time multiplexing the number of individual grants. A separate F-GCH introduces additional complexity in order to vary the power of each time multiplexed grant. Any signaling technique for conveying common or individual grants may be used within the scope of the present invention.

In some embodiments, a relatively large number of individual grant channels (ie, F-GCH) are configured to allow a relatively large number of individual grants at one time. In this case, it is desirable to limit the number of separate authorized channels that each mobile station must monitor. In one example embodiment, various subsets of the total number of individual authorized channels are defined. A subset of individually licensed channels is assigned to each mobile station to monitor. This allows the mobile station to reduce processing complexity and correspondingly reduce power consumption. The tradeoff is scheduling flexibility, since the scheduling base station cannot arbitrarily assign the set of individual grants (e.g., due to design, members of a single group do not monitor one or more individual grant channels, so not all individual grants can be members of a single group). Note that this loss of flexibility does not necessarily result in a loss of capacity. For illustration, consider an example involving four separate grant channels. An even number of mobile stations may be assigned to monitor the first two licensed channels, while an odd number of mobile stations may be assigned to monitor the last two. In another example, the subsets may overlap, eg, an even number of mobile stations monitors the first three licensed channels, while an odd number of mobile stations monitors the last three licensed channels. Obviously, the scheduling base station cannot arbitrarily assign four mobile stations from any group (even or odd). These examples are illustrative only. Any number of channels with any configuration of subsets may be employed within the scope of the present invention.

The remaining mobile stations that have requested but have not received individual grants may be allowed to transmit on the R-ESCH using a common grant that specifies the maximum T/P ratio that each remaining mobile station must adhere to. The shared F-GCH can also be called the forward shared grant channel

(F-CGCH). The mobile station monitors one or more individually granted channels (or a subset thereof) as well as the common F-GCH. Unless a separate authorization is given, a mobile station may transmit if a shared authorization is issued. The shared grant indicates the maximum T/P ratio at which the remaining mobile stations (shared authorized mobile stations) transmit for data with a specific type of QoS.

In an example embodiment, each common grant is valid for some subpacket transmission intervals. Once a common grant has been received, a mobile station that has sent a request but has not received an individual grant may begin transmitting one or more encoder packets within a subsequent transmission interval. Authorization information can be repeated multiple times. This allows the transmission of common grants at a lower power level than individual grants. Each mobile station can combine energy in multiple transmissions to reliably decode a common grant. Thus, a common grant may be selected for mobile stations with poor geometry, for example, when individual grants are considered too expensive in terms of forward link capacity. However, sharing grants still requires overhead, and various techniques for reducing this overhead are detailed below.

The F-GCH is sent by the base station to each mobile station, and the base station schedules each mobile station to transmit new R-ESCH packets. The F-GCH can also be sent during encoder packet transmission or retransmission to force the mobile station to change the T/P ratio for the transmission of subsequent sub-packets of the encoder packet when congestion control is needed.

In an example embodiment, the common grant consists of 12 bits including a 3-bit type field to specify the format of the last 9 bits. The remaining bits indicate the maximum allowable T/P ratios for the 3 classes of mobile stations specified by the Type field, where the maximum allowable T/P ratios for each class are represented by 3 bits. Mobile station type may be based on QoS requirements or other criteria. Many other forms of shared authorization may be envisioned by those skilled in the art, as will be apparent to those skilled in the art.

In an example embodiment, the individual authorization includes 12 bits including: 11 bits specifying the Mobile ID (Mobile ID) and the maximum allowed T/P ratio of the mobile station authorized to transmit, or in To explicitly instruct the mobile station to change its maximum allowed T/P ratio, including setting the maximum allowed T/P ratio to 0 (ie, telling the mobile station not to transmit R-ESCH). These bits specify the mobile station's mobile station ID (1 of 192 values) and the maximum allowed T/P (1 of 10 values) for a particular mobile station. In another embodiment, 1 long-grants bit can be set for a specific mobile station. When the long grant bit is set to 1, the mobile station is authorized to transmit a relatively large fixed predetermined number (updatable by signaling) packets on the ARQ channel. If the long-grant bit is set to 0, the mobile station is authorized to transmit a packet. The mobile station can be told to turn off its R-ESCH transmission with zero T/P ratio specification, and if the long-grant bit is off or if the long-grant bit is on for a longer period, this is used to instruct the mobile station to turn off the R-ESCH Transmission on ESCH which is used for single sub-packet transmission of a single packet.

In an example embodiment, the mobile station only monitors the F-GCH from the serving base station. If the mobile station receives the F-GCH message, the mobile station follows the rate information in the F-GCH message and ignores the rate control bits. Another embodiment uses the following rule for the mobile station, that is, if any rate control indicator of a base station other than the serving base station indicates a rate reduction (i.e., the RATE_DECREASE command detailed below), then the mobile station will will reduce its rate.

In another embodiment, a mobile station may monitor F-GCH from all base stations or a subset of base stations within its active pilot set. Higher layer signaling instructs the mobile station which F-GCHs to monitor and how to combine them on the channel allocation, through handover indication messages or other messages. Note that a subset of F-GCHs from different base stations can be soft combined. The mobile station will be notified of this possibility. After possible soft combining of F-GCHs from different base stations, there will still be multiple F-GCHs at any moment. The mobile station can then decide its transmission rate as the minimum authorized rate (or some other rule).

R-PICH

The reverse pilot channel (R-PICH) is transmitted from the mobile station to the base stations in the active pilot set. The power within the R-PICH may be measured at one or more base stations for reverse link power control. As is known in the art, pilot signals may be used to provide magnitude and phase measurements for coherent demodulation. As mentioned above, the amount of transmit power available to the mobile station (defined by the internal constraints of the scheduling base station or the mobile station's power amplifier) is divided among the pilot, traffic, and control channels. Higher data rates and modulation formats may require additional pilot power. To simplify the use of R-PICH for power control, and to avoid some problems associated with momentary variations in required pilot power, additional channels may be allocated for use as supplementary or auxiliary pilots. Although, typically, as described above, pilot signals are transmitted using known data sequences, information-bearing signals may also be used to generate reference information for demodulation. In an example embodiment, R-RICH is used to carry the desired additional pilot power.

R-RICH

The reverse rate indicator channel (R-RICH) is used by mobile stations to indicate the transport format on the reverse traffic channel R-ESCH. This channel may also be referred to as the Reverse Packet Data Control Channel (R-PDCCH).

R-RICH may be transmitted whenever a mobile station transmits a subpacket. R-RICH with zero rate indication may also be transmitted when the mobile station is idle on R-ESCH. Transmission of a zero-rate R-RICH frame (R-RICH indicating that R-ESCH is not transmitted) enables the base station to detect that the mobile station is idle, maintains reverse link power control of the mobile station, and other functions.

The start of the R-RICH frame is time-aligned with the start of the current R-ESCH transmission. The frame duration of the R-RICH may be equal to or less than the frame duration of the corresponding R-ESCH transmission. R-RICH conveys the transport format of simultaneous R-ESCH transmissions, such as payload, subpacket ID and ARQ event sequence number (AI_SN) bits, CRC for error detection. An example of an AI_SN is a bit that is toggled every time a new packet is transmitted on a particular ARQ, sometimes called a "color bit". This may be an asynchronous ARQ configuration where there is no fixed timing between sub-packet transmissions of a packet. This color bit can be used to prevent the receiver from merging subpackets of one packet with subpackets of adjacent packets on the same ARQ channel. R-RICH can also carry additional information.

R-ESCH

An Enhanced Reverse Supplementary Channel (R-ESCH) is used as the reverse link traffic data channel in the example embodiments described herein. Any number of transmission rates and modulation formats can be used for R-ESCH. In an example embodiment, R-ESCH has the following characteristics: Supports physical layer retransmissions. For retransmission when the first code is a rate 1/4 code, the retransmission uses a rate 1/4 code and uses energy combining. For retransmission when the first code is greater than 1/4 rate, increased redundancy is used. The underlying code is a rate 1/5 code. Additionally, increased redundancy is also available for all cases.

Hybrid Automatic Repeat Request (HARQ) is supported for both autonomous and scheduled users, both of which have access to R-ESCH.

Multiple ARQ-channel synchronous operation can be supported with fixed timing between retransmissions: a fixed number of subpackets between consecutive subpackets of the same packet can be allowed. Alternate transfers may also be allowed. As an example, for a frame of 5 ms, 4 channel ARQ may be supported with a delay of 3 subpackets between subpackets.

Table 1 lists example data rates for the enhanced reverse supplemental channel. A subpacket size of 5 ms is stated, and the corresponding channel is designed to accommodate this choice. Other subpacket sizes may also be chosen, as will be apparent to those skilled in the art. The pilot reference level is not adjusted for these channels, ie the base station has the flexibility to choose T/P for a given operating point. The maximum T/P value is specified on the forward grant channel. If the power to transmit is exhausted, the mobile station can use a lower T/P such that HARQ meets the required QoS. Layer 3 signaling messages can also be transmitted on R-ESCH, allowing the system to operate without R-FCH and/or R-DCCH.

Table 1. Enhanced Reverse Supplementary Channel Parameters

In one example embodiment, turbo encoding is used for all rates. For R=1/4 coding, use an interleaver similar to the current cdma 2000 reverse link. For R=1/5 coding, use an interleaver similar to the cdma 2000 forward packet data channel.

The number of bits per encoder packet includes CRC bits and 6 tail bits. For encoder packets of size 192 bits, a 12-bit CRC is used; otherwise, a 16-bit CRC is used. Consider 5-ms slots separated by 15ms to allow time for ACK/NAK responses. If an ACK is received, the remaining slots of the packet are not transmitted.

The 5 ms subpacket duration and correlation coefficient just described serve as an example only. Any number of combinations of rates, formats, subpacket repetition selections, subpacket durations, etc. will be apparent to those skilled in the art. Another 10 ms embodiment using 3 ARQ channels can be used. In one embodiment, a single subpacket duration or frame size is chosen. For example, choose a 5ms or 10ms structure. In another embodiment, the system may support multiple frame durations.

F-CPCCH

The Forward Common Power Control Channel (F-CPCCH) can be used as a power control variety of reverse link channels when F-FCH and F-DCCH are not present or when F-FCH and F-DCCH are present but not dedicated to the user , including R-ESCH. After channel assignment, the mobile station is assigned a reverse link power control channel. The F-CPCCH may include multiple power control subchannels.

The F-CPCCH may carry a power control subchannel called the Common Congestion Control Subchannel (F-OLCH). The illustrative congestion control subchannel typically has a rate of 100 bps, although other rates can be used. A single bit, referred to herein as the busy bit (which may be repeated for reliability), indicates whether a mobile station in autonomous transmission mode, or in shared grant mode, or both, increases or decreases the mobility The speed of the station. In another embodiment, individual grant modes may also be sensitive to this bit. Various embodiments may be used with any combination of transmission types responsive to F-OLCH. This can be done in a random or deterministic manner.

In one embodiment, setting the busy bit to '0' indicates that mobile stations responding to the busy bit should reduce their transmission rate. Setting the busy bit to '1' indicates a corresponding increase in the transfer rate. It will be apparent to those skilled in the art that a number of other signaling schemes may be used, and various other examples are detailed below.

During the channel assignment process, mobile stations are assigned to these specific power control channels. The power control channels may control all mobile stations in the system, or one or more power control channels may control a variable subset of mobile stations. Note that the use of this specific channel for congestion control is just one example.

F-ACKCH

The Forward Acknowledgment Channel, or F-ACKCH, is used by the base station to acknowledge correct receipt of the R-ESCH, and this channel can also be used to extend existing grants. An acknowledgment (ACK) on the F-ACHCH indicates correct receipt of the subpacket. No additional transmission of this subpacket by the mobile station is required. A negative acknowledgment (NAK) on the F-ACKCH allows the mobile station to transmit another subpacket, limited by the maximum allowed number of subpackets per packet.

In the embodiment described in detail here, the F-ACKCH is used to provide a positive or negative acknowledgment of receiving subpackets, and an indication of whether to issue a rate control command (described below for the F-RCCH channel).

Figure 5 is an example embodiment illustrating a three-valued F-ACKCH. The example F_ACKCH includes a single indicator transmitted from one or more base stations to the mobile station to indicate whether a transmission on the R-ESCH from the mobile station has been correctly received by the base stations. In one example embodiment, the F-ACKCH indicator is transmitted by each base station in the active pilot set. Additionally, F-ACKCH may be transmitted by a specific subset of the active pilot set. The set of base stations sending F-ACKCH may be referred to as an effective pilot set of F-ACKCH. The F-ACKCH active pilot set may be indicated by Layer 3 (L3) signaling to the mobile station, and may be specified in a Handover Direction Message (HDM) during the channel allocation process or by other techniques known in the art.

For example, F-ACKCH may be a 3-state channel with the following values: NAK, ACK_RC, and ACK_STOP. NAK indicates that the packet sent from the mobile station must be retransmitted (however, if the last subpacket has been sent, the mobile station may need to retransmit the packet using any existing techniques such as request/grant, rate control or autonomous transmission). If the NAK corresponds to the last subpacket of the packet, the mobile station may need to monitor the rate control indicator on the corresponding F-RCCH (further described below).

ACK_RC indicates that no packet retransmission is required from the mobile station, and the mobile station should monitor the rate control indicator on the corresponding F-RCCH. ACK_STOP also indicates that no retransmission is required. However, in this case the mobile station should revert to autonomous mode for the next transmission unless the mobile station receives a grant message on the F-GCH (as detailed above).

L3 signaling may indicate to the mobile station whether to soft combine F-ACKCH indicators from different base stations in its active pilot set. This may be equivalent to processing power control bits according to revision C of IS-2000. For example, there may be an indicator, let's say ACK_COMB_IND, sent in a handover message after channel allocation, which indicates whether the mobile station combines F-ACKCH indicators from different base stations. Various techniques may be used to transmit F-ACKCH, examples of which are given below. Some examples include separate TDM channels, TDM/CDM channels, or other formats.

In this example, monitoring the F-ACK channel has two types of results depending on whether the packet is acknowledged or not. If a NAK is received, several options are available. The mobile station may send additional subpackets until the maximum number of subpackets is sent. (In this example embodiment, the subpackets are sent using the same transport format whether initiated by an autonomous or authorized transport, and whether rate-controlled or not. In another embodiment, any of the techniques disclosed herein may be used Change the subpacket transmission format). After the NAK of the last subpacket, the mobile station can act according to the corresponding rate control command (monitor the F-RCCH), stop transmission according to the previous grant or rate control command (i.e., revert to autonomous transmission if necessary), or respond to a new received authorization.

If an ACK is received, it may stop according to a rate control command or indication. If rate control is indicated, the rate control channel (F-RCCH) is monitored and tracked. If the result is stalled, the mobile station does not track the rate control indicator on the F-RCCH and reverts to autonomous mode (transmitting to reach the allocated maximum autonomous rate). If an explicit grant is received concurrently with ACK_STOP, the mobile station follows the commands in the explicit grant.

For example, first consider the case when a single valid pilot set member or indicators from all parts are the same (and indicated by ACK_COMB_IND). In this case, there is a single composition indicator. When the mobile station receives a NAK (not to transmit indicator), then the mobile station retransmits the next subpacket (at the appropriate time). If the mobile station does not receive an ACK for the last subpacket, the mobile station continues with the next packet (error packets may be retransmitted according to whatever retransmission algorithm is followed). However, the mobile station considers this a rate control indication (ie monitors the rate control channel).

In this example, the following are general rules (applicable to both a single active pilot set member and multiple different F-ACKCH active pilot set members). If any indicator is ACK_STOP or ACK_RC, the result is ACK. If none of the indicators are ACK_STOP or ACK_RC, the result is NAK. Then, related to rate control, if any indicator is ACK_STOP, the mobile station will stop (ie revert to autonomous mode or respond to any grant). If none of the indicators are ACK_STOP and at least one indicator is ACK_RC, the indicators on the rate control channel (F-RCCH) of the corresponding base station are decoded. If the last subpacket has been transmitted and all indicators are NAK, the indicators on the rate control channel (F-RCCH) of all base stations are decoded. The following description of the F-RCCH further details the response to rate control commands in these cases.

The ACK_RC command, together with the rate control channel, can be considered as a type of command called ACK_continue (ACK-and-Continue). The mobile station may continue to transmit subsequent packets, according to the various rate control commands that may be issued (examples of which are detailed below). The ACK_Persistent command allows the base station to acknowledge a successfully received packet and, at the same time, allows the mobile station to transmit with the grant that resulted in the successfully received packet (according to a possible revision of the rate control command). This saves the overhead of new authorizations.

In the F-ACKCH embodiment, as depicted in Figure 5, a positive value for the ACK_STOP symbol, a null symbol for NAK, and a negative value for the ACK_RC symbol are used. On-keying (ie, not sending NAKs) on the F-ACKCH allows base stations (especially non-scheduling base stations) not to send ACKs when the consumption (required power) is too large. This provides the base station with a trade-off between forward link and reverse link capacity since a correctly received packet that is not ACKed will likely cause a retransmission at a later time.

A variety of techniques for sending F-ACKCH may be used within the scope of the present invention. The individual signals of each mobile station can be combined in a common channel. For example, acknowledgment responses for multiple mobile stations may be time multiplexed. In an example embodiment, up to 96 mobile station IDs can be supported on one F-ACKCH. Additional F-ACKCHs may be configured to support additional mobile station IDs.

Another example is to map multiple acknowledgment signals to multiple mobile stations onto a set of orthogonal functions. A Hadamard encoder is an example of an encoder for mapping to sets of orthogonal functions. Other different techniques can also be used. For example, any Walsh code or other similar error correcting code can be used to encode the information bits. If each independent sub-channel has an independent channel gain, different users can transmit at different power levels. The illustrative F-ACKCH conveys a dedicated three-valued flag for each user. Each user monitors F-ACKCHs from all base stations in its active pilot set. (Alternatively, the signal may also define a reduced set of effective pilots to reduce complexity).

In various embodiments, the two channels are each covered with a 128-chip Walsh cover sequence. One channel is transmitted on the I channel and the other is transmitted on the Q channel. Another embodiment of F-ACKCH uses a single 128-chip Walsh overlay sequence to support up to 192 mobile stations simultaneously. An example embodiment uses a 10 ms duration for the three-valued flag.

For rechecking, when a mobile station wants to send a packet that needs to use R-ESCH, it needs to request on R-REQCH. The base station may respond to an authorization to use the F-GCH. However, this operation can be somewhat expensive. In order to reduce forward link overhead, F-ACKCH can issue ACK_RC flags, which can extend existing grants at low cost (according to rate-controlled ). This method can be used for both individual authorizations and pooled authorizations. ACK_RC is used from the granting base station (or base stations) and extends the current grant to another encoder packet on the same ARQ channel (according to rate control).

Note that, as shown in Figure 4, there is no need for every base station in the active pilot set to send back an F-ACKCH. The set of base stations sending F-ACKCH in soft handover may be a subset of the active pilot set. An example technique for transmitting F-ACKCH is in the document entitled "Code Division Multiplexing Command on a Code Division Multiplexing Channel", filed June 30, 2003, assigned to the assignee of the present invention. Disclosed in US Patent Application Serial No. 10/611,333.

F-RCCH

A Forward Rate Control Channel (F-RCCH) is transmitted from one or more base stations to the mobile station to indicate a rate adjustment for the next transmission. A mobile station can be assigned to monitor indicators sent from each member of the F-ACKCH active pilot set or a subset thereof. For clarity, the set of base stations transmitting the F-RCCH to be monitored by the mobile station will be referred to as the F-RCCH Active Pilot Set. The F-RCCH active pilot set may be indicated by Layer 3 (L3) signaling, which is specified during the channel allocation process, in a Handover Direction Message (HDM), or any of a variety of other methods known to those skilled in the art.

6 depicts an illustrative F-RCCH. F-RCCH is a 3-state channel with the following values: RATE_HOLD, indicating that the mobile station can transmit the next packet at the same rate as the current packet; RATE_INCREASE, indicating that the mobile station can be determined or randomly relative to the transmission rate of the current packet. increase the maximum rate at which the next packet is transmitted; and RATE_DECREASE, which indicates that the mobile station can deterministically or randomly reduce the maximum rate at which the next packet is transmitted relative to the current packet transmission rate.

The L3 signaling may indicate to the mobile station whether rate control indicators from different base stations are to be combined. This is similar to what is done for the power control bits in IS-2000 Revision C. Thus, there will be an indicator sent on the channel assignment and within the handover message, eg RATE_COMB_IND, which will indicate to the mobile station whether to soft combine F-RCCH bits from different base stations. Those skilled in the art will recognize that there are many forms of transport channels such as F-RCCH, including split TDM channels, combined TDM/CDM channels, or other forms.

In different embodiments, different rate control configurations are possible. For example, all mobile stations may be controlled by a single indicator per part. In addition, each mobile station may be controlled by separate indicators for each section specific to each mobile station. Alternatively, a group of mobile stations may be controlled by its own assigned indicators. This configuration allows mobile stations with the same maximum QoS class to be assigned the same indicator. For example, all mobile stations whose only codestreams are indicated as "best effort" can be controlled by one assigned indicator, which allows reducing the load of these best effort codestreams.

In addition, signaling can be used to configure the mobile station to focus only on F-RCCH indicators from the serving base station or from base stations within the F-RCCH active pilot set. Note that if the mobile station only monitors the indicator from the serving base station and the RATE_COMB_IND specifies that the indicator is the same as indicators from multiple base stations, the mobile station can combine all indicator. The set of base stations with different rate control indicators used at any time will be referred to as the current set of F-RCCH. Thus, the size of the F-RCCH current set is one if the mobile station is configured such that the mobile station only pays attention to the F-RCCH indicators from the serving base station.

It can be considered that the usage rules for F-RCCH can be adjusted by the base station. The following is an example of a rule set for a mobile station with a single-member F-RCCH common set. If RATE_HOLD is received, the mobile station does not change its rate. If RATE_INCREASE is received, the mobile station increases its rate by 1 (ie, a rate class, an example of which is detailed in Table 1 above). If RATE_DECREASE is received, the mobile station decrements its rate by one. Note that the mobile station only monitors these indicators when circumstances require (ie, the operation of indicating rate control as a result of the ACK procedure detailed further below is in effect).

The following is an example of a rule set for a mobile station with multiple F-RCCH common set members. A simple rule change that increases/decreases the rate by 1. If any ACK_STOP is received, the mobile station reverts to the autonomous rate. Otherwise, if any indicator is RATE_DECREASE, the mobile station decreases its rate by one. If no indicator is RATE_DECREASE, and at least one base station has rate controlled operation (as a result of the ACK procedure) indicating RATE_HOLD, then the mobile station maintains the same rate. If no indicator is RATE_DECREASE, no base station indicates rate control and RATE_HOLD, and at least one base station has rate controlled operation and indication of RATE_INCREASE; then the mobile station increments its rate by one.

Example of Combining Grant, ARQ, and Rate Control Command Embodiments

Summarizing some of the aspects introduced above, a mobile station can be authorized to make autonomous transmissions, which, although possibly limited in throughput, still allows for low latency. In this case, the mobile station can transmit without requesting the maximum R-ESCH T/P ratio, T/Pmax_auto (T/PMax_auto), which can be set and adjusted by the base station through signaling.

Scheduling may be determined at one or more scheduling base stations, and allocation of reverse link capacity may be made through grants to transmit at a relatively high rate on the F-GCH. In addition, rate control commands can be used to modify previously granted or autonomous transmissions with low overhead, thereby adjusting the allocation of reverse link capacity. Scheduling can thus be used to tightly control the reverse link load and thereby protect voice quality (R-FCH), DV feedback (R-CQICH) and DV acknowledgment (R-ACKCH).

Individual authorization allows precise control of mobile station transmissions. Mobile stations can be selected based on geometry and QoS to maximize throughput while maintaining the required level of service. Sharing grants allows efficient notification, especially for poor geometry mobile stations.

The F-ACKCH channel combined with the F-RCCH channel effectively implements the "ACK-continue" order, which extends existing grants at low cost. (The duration may be rate controlled, as described above, and described in further detail below). It applies to individual licenses and pooled licenses. Various embodiments and techniques for scheduling, granting, and transmission on a shared resource such as the 1xEV-DV reverse link are contained in a document entitled "Scheduling and Autonomous Transmission and Acknowledgment," US Patent Application No. 10/646,955, which is hereby incorporated by reference.

7 depicts an example methodology 700 by which one or more base stations can be configured to allocate capacity to respond to requests and transmissions from one or more mobile stations. Note that the order of the blocks shown is an example only, and the order of various blocks may be interchanged or combined with other blocks, not shown here, without departing from the scope of the invention. The process begins at block 710 . A base station receives a request for transmission, which may be transmitted by one or more mobile stations. Since the method 700 can be repeated indefinitely, there may be previous requests also received, which may not be authorized, which can be combined with new requests to estimate the demand for transmission according to the requests.

In block 720, one or more mobile stations may transmit subpackets received by the base station. The transmitted sub-packets may be transmitted pursuant to previous authorization (possibly changed by previous rate control commands) or autonomously (possibly also changed by previous rate control commands). The number of autonomous transmissions, the number of registered mobile stations, and/or other factors may be used to estimate the demand for autonomous transmissions.

In block 730, the base station decodes any received subpackets, optionally soft combining each previously received subpacket, to determine whether the packet has been received error-free. This decision will be used to send a positive or negative acknowledgment to each transmitting mobile station. Consider that HARQ can be used as packet transmission on R-ESCH. That is, a packet may be transmitted a certain number of times until it is correctly received by at least one base station. At each frame boundary, each base station decodes the R-RICH frame and determines the form of transmission on the R-ESCH. The base station may also use the current R-RICH frame and the previous R-RICH frame to make this determination. Alternatively, the base station may also use other information extracted from the Reverse Supplementary Pilot Channel (R-SPICH) and/or R-ESCH to make the determination. From the determined transmission form, the base station attempts to properly decode this packet on the R-ESCH using previously received subpackets.

In block 740, the base station performs scheduling. Any scheduling technique can be used. The base station may manage to perform scheduling to allocate shared resources (in this example, reverse link capacity) as required by requested transmissions, desired autonomous transmissions, estimates of current channel conditions, and/or various other parameters. Scheduling can take a variety of forms for a variety of mobile stations. Examples include making grants (allocating as requested, increasing previous grants, or decreasing previous grants), generating rate control commands to increase, decrease, or maintain previously granted rates or autonomous transmissions, or ignoring requests (turning mobile stations into autonomous transmissions) ).

In step 750, the base station processes the received transmissions for each mobile station. Among other functions, this may include acknowledging received sub-packets and conditionally generating authorization in response to transmitted requests.

FIG. 8 depicts an example method 750 of generating grant, acknowledgment, and rate control commands. This method is suitable for deployment in the example method 700 depicted in FIG. 7, and may be suitable for other methods that will be apparent to those skilled in the art. Method 750 may be repeated for each active mobile station during each pass through method 700, as described above.

In decision block 805, if no sub-packet has been received for the mobile station being processed, proceed to block 810. No acknowledgment is required and no rate control commands are issued. Neither F-ACKCH nor F-RCCH needs to be transmitted, and both symbols can be DTXed (not transmitted). In decision block 815 , if a request has been received, proceed to block 820 . Otherwise the process stops.

In decision block 820, if a grant has been determined for the mobile station during the scheduling process, proceed to block 825 to transmit the grant on the appropriate F-GCH. The process can then be stopped. The mobile station may transmit in accordance with the grant during the next appropriate frame (synchronization examples are detailed below with reference to FIGS. 10-12 ).

Returning to decision block 805, if a subpacket is received from the mobile station, then proceed to decision block 830. (Note that subpackets and requests may be received, in which case both branches from decision block 805 may be performed on the mobile station, details not shown for clarity).

In decision block 830, if the received subpacket was decoded correctly, an ACK will be generated. Proceed to decision block 835. If rate control (including rate maintenance, ie, "continuous") is desired, proceed to block 845 . If rate control is not required, proceed to block 840 . In block 840, transmit ACK_STOP on the F-ACKCH. No F-RCCH needs to be transmitted, ie, DTX can be generated. If no authorization is generated at this time, the mobile station will be reverted to autonomous transmission (or must stop if autonomous transmission is not available or configured). Additionally, a new authorization can be issued which will override the stop order. Proceed to decision block 820 to process the decision, as described above.

In block 845, rate control is assigned. As such, ACK_RC will be transmitted on F_ACKCH. Proceed to decision block 850 . If an increase is required, transmit RATE_INCREASE on F_RCCH. Then the process can end. If no increase is required, proceed to decision block 860 . In decision block 860, if a decrease is required, RATE_DECREASE is transmitted on the F_RCCH. The process can then be stopped. Otherwise, RATE_HOLD is transmitted on F-RCCH. In this example, Hold is indicated by DTX. The process can then be stopped.

Returning to decision block 830, if the received subpacket was not decoded correctly, a NAK will be generated. Proceed to block 875 to transmit the NAK on the F-ACKCH. In this example, NAK is indicated by DTX. Proceed to decision block 880 to determine whether the received subpacket is the last subpacket (ie, the maximum number of subpacket retransmissions has been reached). If not, in this instance, the mobile station can retransmit in the form of the previous transmission. DTX may be transmitted on the F-RCCH, as indicated in block 895 . (In this case, other embodiments may perform other signaling, examples of which are described below.) The process may then end.

If the subpacket has been received and NAKed, then the subpacket is the last subpacket, proceed from decision block 880 to decision block 885 to determine whether rate control (including hold) is required. This is an example technique for extending previously granted or autonomous transmissions (including previous rate control, if present) with low overhead. DTX is generated for F-RCCH if rate control is not required. In this example, the mobile station will transmit the next subpacket. Similar to decision block 835, if no new authorization is generated for the mobile station, the mobile station will be reverted to autonomous transmission (if possible). Additionally, new grants can be generated which will indicate possible transmissions for the mobile station. Proceeding to decision block 820 to perform this determination, as described above.

At decision block 885, proceed to block 850 if rate control is required. An increase, decrease, or maintenance of transmissions on the F-RCCH may be generated, as described above. The process can then end.

As a summary, the base station may send an acknowledgment if the packet is received correctly, and may conditionally send a rate control message to the mobile station.

The base station can send ACK_STOP (on F-ACKCH) to indicate that the packet has been delivered and the mobile station reverts to autonomous mode for the next transmission. The base station can also send a new grant if needed. The mobile station can transmit to achieve the authorized rate for the next transmission. In each case, the F-RCCH goes through DTX. In one embodiment, only the serving (or authorizing) base station may generate grants. In another embodiment, one or more base stations may generate grants (details of operating this option are detailed below).

The base station can send ACK_RC (on F-ACKCH) and RATE_HOLD (on F_RCCH) to indicate that the packet is delivered and that the mobile station transmits the next packet at the same maximum rate as the current packet.

The base station can send ACK_RC (on F-ACKCH) and RATE_INCREASE (on F-RCCH) to indicate that the packet is delivered and that the mobile station can increase the maximum rate for the next packet transmission relative to the current packet transmission rate. The mobile station can increase the rate following certain laws known to the base station and the mobile station. This increase can be deterministic or random. Those skilled in the art will recognize various laws of increasing the rate.

The base station can send ACK_RC (on F-ACKCH) and RATE_DECREASE (on F-RCCH) to indicate that the packet is delivered and that the mobile station can reduce the maximum rate of transmission of the next packet relative to the transmission rate of the current packet. The mobile station can reduce the rate according to the following specific rules known to the base station and the mobile station. This reduction can be deterministic or stochastic. Those skilled in the art will recognize various laws of reducing the rate.

If the base station does not successfully receive the packet, and the packet can be retransmitted again (ie, not the last subpacket), the base station sends a NAK on the F-ACKCH. Note that F-RCCH goes through DTX in this example.

If further retransmission of the packet (ie, the last sub-packet) is not allowed, the following are possible actions that the base station can take. The base station can send a NAK (on the F-ACKCH) and at the same time send a grant message on the F-GCH to indicate to the mobile station that the packet was not delivered and that the mobile station can transmit to reach the authorized rate for the next transmission. In this case, F-RCCH goes through DTX. In one embodiment, only the serving (or authorizing) base station may generate grants. In another embodiment, one or more base stations may generate grants (details of handling this selection are detailed below).

The base station can also send NAK (on F-ACKCH) and RATE_HOLD (on F-RCCH) to indicate that the packet was not delivered and that the maximum rate at which the mobile station can transmit the next packet is the same as the transmission rate of the current packet.

The base station can also send NAK (on F-ACKCH) and RATE_INCREASE (on F-RCCH) to indicate that the packet was not delivered and that the mobile station can increase the maximum rate for the next packet transmission relative to the current packet transmission rate. The mobile station can increase the rate according to a certain law known to the base station and the mobile station. This acceleration can be deterministic or stochastic.

The base station may also send NAK (on F-ACKCH) and RATE_DECREASE (on F-RCCH) to indicate that the packet was not delivered and that the mobile station should reduce the maximum rate for the next packet transmission relative to the current packet transmission rate. The mobile station can reduce the rate according to a certain law known to the base station and the mobile station. This deceleration can be deterministic or random.

In another embodiment (details not shown in Figure 8), another form of NAK and stall can be generated. For example, in the above case, DTX on F-RCCH corresponding to NAK cannot be distinguished from "NAK-and-hold". If a command is required to force a stop (or revert to autonomous transmission), the base station can also use a NAK and rate control before the last subpacket to indicate that the rate of the last subpacket remains (or increases, or decreases) to indicate a stop. For example, in this particular case, any one of the rate control commands (ie, RATE_INCREASE, RATE_DECREASE, or RATE_HOLD) could be assigned to indicate a stop. The mobile station will know when the last subpacket was transmitted and can then analyze the rate control commands accordingly. When the base station knows whether the last subpacket transmission should be followed by a cessation of NAK events, the selected rate control command can be issued together with the NAK of the previous subpacket. A mobile station receiving a determined rate control command with a NAK on a subpacket (not the last) knows that the NAK on the last subpacket (and RATE_HOLD, for example) indicates that any previous grants are revoked, and the mobile station must revert to autonomous transmission. Rate control commands not used for this purpose (ie, RATE_INCREASE or RATE_DECREASE ) transmitted with the last subpacket NAK are still available. Another solution is to transmit the grant at zero (or reduced) rate along with the final NAK, although this would require additional overhead. Those skilled in the art can easily replace these schemes with other possible schemes according to the possibility of "NAK-and-stop". The required overhead can be optimized based on the likelihood of various events.

9 depicts an example methodology 900 for a mobile station to monitor and respond to grant, acknowledgment, and rate control commands. The method is suitable for use in one or more mobile stations operating in conjunction with one or more base stations using method 700 as described above, as well as other base station embodiments.

The process begins at block 910 . The mobile station monitors F-GCH, F-ACKCH and F-RCCH. Note that in various embodiments, the mobile station may monitor one or more of these channels, as described above. For example, there may be multiple authorized channels, and each mobile station may monitor one or more of them. Note also that each of these channels can be received from one base station, or can be received from more than one base station when the mobile station is in soft handoff. A channel may contain messages or commands directed to multiple mobile stations, so a mobile station can extract messages or commands directed specifically to that mobile station.

Other algorithms may be used to allow a mobile station to conditionally monitor one or more of the control channels. For example, as described above, the F-RCCH may not be transmitted when ACK_STOP is issued. Thus, in this case, the mobile station does not need to monitor the F-RCCH while receiving ACK_STOP. A rule can be specified that a mobile station only looks for grant messages and/or rate control commands if the mobile station has sent a request that can be responded to by those messages.

In the following description of FIG. 9, it can be considered that the mobile station has previously transmitted a subpacket and expects an acknowledgment (including possibly a grant or rate control command) response to this subpacket. If there was no previous request for authorization, the mobile station may still monitor authorization in response to a previously transmitted request. Those skilled in the art can easily modify method 900 to accommodate this situation. Mobile stations of these and other possible processing blocks are omitted for clarity of illustration.

From decision block 915, processing of the F-ACKCH begins. The mobile station extracts information on all F-ACKCH channels it monitors. Consider that there can be an F-ACKCH between a mobile station and each member of its F-ACKCH active pilot set. Some F-ACKCH orders may be soft combined, as specified via L3 signalling. If the mobile station receives at least one acknowledgment, ACK_RC or ACK_STOP (on F-ACKCH), the current packet has been correctly received and no additional subpackets need to be transmitted. If there is a next packet, you need to determine its allowable transmission rate.

In decision block 915, if ACK_STOP has been received, the mobile station knows that the previously transmitted subpacket has been received correctly and does not need to decode the rate control command.

In decision block 920, the mobile station determines whether a grant has been received on the F-GCH. If so, the mobile station transmits the next packet in accordance with the authorization, as indicated in block 930 . In one embodiment, only one authorized base station authorizes. If an ACK_STOP and a grant message are received from the base station, the mobile station transmits new packets on the same ARQ channel at any rate equal to or lower than the grant rate.

In another embodiment, more than one base station may send grants. If the base station coordinates the grants and sends the same message, the mobile station can soft combine those grants. Various algorithms can be used to handle situations where different authorizations are received. One example is to have the mobile station transmit at the lowest rate specified in the received grant to avoid excessive interference within the cell corresponding to the respective authorized base station (including ACK_STOP without corresponding grant - indicating that the transmission should revert to autonomous mode). Various other protocols will be apparent to those skilled in the art. If no grant is received within decision block 920, the mobile station must return to autonomous rates, as indicated in block 925. The process can then end.

Returning to decision block 915, if ACK_STOP is not received, proceed to decision block 940. If ACK_RC is received, the mobile station monitors the corresponding F-RCCH of the base station and, if present, receives an acknowledgment from the base station. Note that there is no F-RCCH between the base station and the mobile station, because the effective pilot set of F-RCCH is a subset of the effective pilot set of F-ACKCH. Note also that when a mobile station receives F-ACKCHs from multiple base stations, the corresponding messages may be in collision. For example, one or more of an ACK_STOP command, an ACK_RC command, and a grant, or a combination thereof, may be received. Those skilled in the art will recognize numerous laws to implement to handle any of the possibilities. For example, the mobile station may determine the lowest possible transmission allowance (which may be from an ACK_STOP with no grant, an ACK_RC with a reduced amount, or a grant with a lower value) and transmit accordingly. This is similar to a technique known as the "OR-of-Downs" rule. This technique can be used to strictly avoid excessive interference to neighboring cells. Alternatively, one or more base stations may have priorities assigned to them such that one or more base stations may have capabilities over others (possibly with additional conditions). For example, a scheduling (or granting) base station may have higher priority over other base stations in soft handover. Other laws are also envisioned. (Consider that one or more NAKs can also be received, but the mobile station need not retransmit. However, if desired, the mobile station can similarly include rate control commands or grants from the base station in the NAK.) To help Note that when it is considered that the mobile station determines whether ACK_STOP, ACK_RC, NAK or grant is received, the result can be obtained by applying the appropriate set of rules on some commands received, and the result is the recognized command.

If ACK_PC has been received, proceed to decision block 945 to begin determining what rate control command should be followed. If the indication has increased, proceed to block 950 . The next transmission may be transmitted on the same ARQ channel at an increased rate relative to the current rate. The process can then end. As above, this increase can be deterministic or random. Also, RATE_INCREASE does not necessarily increase the rate immediately, but can increase the transmission rate from the mobile station at a later time (ie, using a credit-like algorithm at the mobile station), or RATE_INCREASE can increase multiple rates. In one example credit algorithm, the mobile station maintains an internal "balance/credit" parameter. The mobile station increments this parameter whenever the mobile station receives RATE_INCREASE but cannot increase its rate (because the mobile station runs out of power or data). When power or data is available to the mobile station, it can use the stored "credit/balance" when selecting a data rate. Various methods of increasing the rate will be apparent to those skilled in the art.

If no increase is specified in decision block 945, then proceed to decision block 955 to determine if deceleration is specified. If deceleration is specified, proceed to block 960 . The next transmission may be transmitted on the same ARQ channel at a reduced rate relative to the current rate. Then, the process stops. As above, this deceleration can be deterministic or random. Also, RATE_DECREASE does not necessarily result in an immediate rate reduction, but may reduce the transmission rate from the mobile station at a later date (i.e., the mobile station uses a credit-like algorithm), or RATE_DECREASE may result in a deceleration across multiple rates . When the example credit algorithm is used in the case of RATE_DECREASE, and when the mobile station gets the RATE_DECREASE but fails to comply for some reason (for example, urgent data needs to be sent), the RATE_DECREASE gets a negative credit, and in a sense, the negative credit needs was subsequently repaid. Various methods of reducing the rate will be apparent to those skilled in the art.

If neither increase nor decrease is indicated, RATE_HOLD has been received. The mobile station may transmit the next packet at a maximum rate equal to the current packet rate, as indicated in block 965 . Then, the process can end.

Returning to decision block 940, if the type of ACK is not identified, it will be determined that a NAK has been received. In decision block 970, if the packet is still likely to be retransmitted (i.e., the current subpacket is not the last subpacket), the mobile station retransmits the subpacket on the same ARQ channel with the ID of the subpacket incremented, as in block 980 painted.

In decision block 970, if the current packet is the last subpacket, then the mobile station has completed retransmission of all packets. Proceeds to decision block 975 to determine if authorization has been received (in a similar manner to block 920 described above). If a grant message is assigned to the mobile station (whether from a single base station or multiple base stations, as described above), the mobile station can transmit new packets on the same ARQ channel at a rate equal to or lower than the grant rate. Proceed to block 930 as described above.

In decision block 975, if a grant has not been received, the mobile station may monitor the F-RCCH active pilot set, obtain rate control commands, and determine the maximum rate allowed to transmit the next packet on the same ARQ channel. Selection of the rate when more than one rate control command is received may be made as described above. Proceed to decision block 945 and continue as described above.

A variety of other techniques may be used by the illustrative embodiments of the mobile station. The mobile station can monitor the number of packet deletions (ie, no acknowledgments after the last subpacket). The measurement can be made by counting the number of consecutive packet deletions or the number of deleted packets within a window (ie, a sliding window). If the mobile station identifies that too many packets have been dropped, it may reduce its transmission rate despite the rate control command indicating other commands (ie, RATE_HOLD or RATE_INCREASE).

In one embodiment, grant messages may have higher priority than rate control bits. Additionally, grant messages may be processed with the same priority as rate control bits. In this case the rate determination can be changed. For example, if no grant message is intended for the mobile station, the rate of the next packet can be determined from all rate control commands (RATE_INCREASE, RATE_HOLD, RATE_DECREASE, and ACK_STOP) using an "OR-of-DOWN" or similar algorithm. When a grant is also received, the rate for the next transmission can be determined from all rate control commands (RATE_INCREASE, RATE_HOLD, RATE_DECREASE, and ACK_STOP) using an "OR-or-Down" or similar algorithm, the results of which are compared to the grant rate, and Choose a smaller rate.

Signaling may be used to configure the mobile station to monitor the F-RCCH indicators only from the serving base station or from all base stations within the F-RCCH active pilot set. For example, when RATE_COMB_IND may specify that the rate control command is the same as rate control commands from multiple base stations, then the mobile station may combine all indicators in the identified group before making a decision. The number of different indicators used at any time can be indicated as the F-RCCH common set. In one example, a mobile station can be configured to monitor only F-RCCH indicators from the serving base station, in which case the F-RCCH common set has a size of one.

Additionally, as described above, various algorithms may be used to adjust the rate in response to commands on the F-RCCH. Any of these laws can be adjusted using signaling from the base station. In one embodiment, a set of probabilities and step sizes may be used in determining whether and by how much a mobile station increases or decreases its rate. These probabilities and possible rate span sizes may be updated by signaling if necessary.

Method 900 can be used to include a variety of alternatives as described for base stations using method 750 described above. For example, in one embodiment, the NAK and end order are not explicitly defined when the DTX on the F-RCCH with the NAK indicates a rate hold. In another embodiment, the NAK and end functions may be used to correspond to any of the alternative techniques for method 750 described above. Also, as described above with respect to method 750, in an example embodiment, rate control or grant-based rate alteration is performed at packet boundaries. It is contemplated that the illustrated method may also be modified to include inter-subpacket rate changes.

Any of the procedures and features described herein can be combined in various ways as will be apparent to those skilled in the art from the disclosure herein. For example, a mobile station may only be controlled by the primary base station through grants and not by other base stations through rate control bits. Additionally, a mobile station may be controlled by grants from all base stations or a subset of base stations within its active pilot set. Some F-GCHs can be soft combined. The mode of operation of the mobile station can be set by L3 signaling during channel allocation or by other messages during packet data calls.

As another example, the master base station may send ACK_STOP or ACK_RC if the packet is received correctly. Rate control commands may not be used, so ACK_RC may be used to refer to this mode as "ACK and Continue". In this case, "ACK and Continue" indicates that the mobile station can transmit new packets at the same rate as packets it is acknowledging. As mentioned before, if ACK_STOP is sent, the base station may also send the coverage grant on the F-GCH designated for the MS. In this instance, the NAK will indicate "NAK and stop" unless a corresponding authorization is transmitted with the NAK. In this case, the non-primary base station also sends ACK_STOP or ACK_RC, where ACK_RC is not accompanied by a rate control command and indicates "ACK and continue".

In another example specific mode, mobile stations comprising the subset of characteristics described can be controlled only by rate control bits (from base stations within their F-RCCH active pilot set). This mode can be set through L3 signaling during channel assignment or through other messages during packet data calls. In this mode, if the packet is not successfully received, the base station sends a NAK. When the packet is received correctly, the base station can send ACK_STOP or ACK_RC together with F-RCCH (RATE_HOLD, RATE_INCREASE, or RATE_DECREASE). The NAK after the last subpacket may be appended with F-RCCH (RATE_HOLD, RATE_INCREASE, or RATE_DECREASE).

10-12 schematically illustrate examples of synchronization of the various channels described herein. This example does not represent any particular chosen frame length, but illustrates the relative synchronization of grant, ACK, and rate control (RC) indicators. The ACK indicator, RC indicator, and grant occur during the same time interval so that the mobile station receives the ACK, RC, and grant information at approximately the same time that the next packet transmission applies. In these examples, the mobile station does not need to monitor the RC except when it receives an acknowledgment or when all subpackets have been transmitted (as described in the example embodiments above). The mobile station monitors the ACK bits allocated to the mobile station and to the RC indicator according to a particular ARQ sequence. For example, if there are four ARQ sequences, and the mobile station transmits on all ARQ sequences, then the mobile station monitors a per-frame ACK indicator and a per-frame RC indicator (where applicable). Null frames between various transmissions are introduced to allow time for the base station or mobile station to receive and decode requests, transmission subpackets, grants, acknowledgments, and rate control commands, as applicable.

Note that these synchronization diagrams are not exhaustive and are used only to illustrate the various aspects described above. Combinations of various sequences will be recognized by those skilled in the art.

Figure 10 depicts synchronization of an example embodiment with combined acknowledgment and rate control channels. The mobile station transmits a request transmitted on R-REQCH. The base station then transmits a grant on the F-GCH in response to the request. The mobile station then transmits the first subpacket using the parameters according to the authorization. This subpacket was not decoded correctly at the base station, as indicated by the strikethrough of the subpacket transmission. The base station transmits ACK/NAK transmission on F-ACKCH and rate control command on F-RCCH. In this example, NAK is transmitted and F-RCCH goes through DTX. The mobile station receives the NAK and retransmits the second subpacket in response. This time, the mobile station correctly decodes the second subpacket and sends the ACK/NAK transmission on the F-ACKCH and the rate control command on the F-RCCH again. In this instance, no additional authorization is transmitted. ACK_RC is transmitted and a rate control command is issued (which command may indicate an increase, decrease or hold as determined by the desired schedule). The mobile station then transmits the first subpacket of the next packet using the parameters associated with the grant as must be changed by a rate control command on the F-RCCH.

Figure 11 depicts synchronization of an example embodiment with combined acknowledgment and rate control channels and new grants. Transmission request, grant, sub-packet transmission (not decoded correctly) and NAK are the same as the above first eight frames according to FIG. 10 . In this example, the second sub-packet transmission may also be correctly received and decoded. However, ACK_STOP is transmitted instead of ACK_RC sent by the base station. If no grant is attached to ACK_STOP, the mobile station shall revert to autonomous transmission. Instead, a new authorization is transferred. The mobile station does not need to monitor the F-RCCH for this frame. The mobile station then transmits the first subpacket of the next packet according to the new grant.

Figure 12 depicts synchronization of an example embodiment with combined acknowledgment and rate control channels, but no grants. This example is the same as Figure 10 except no grant is sent in response to the initial mobile station request. In this way, the first subpacket transmission of the first packet is transmitted at an autonomous rate. Again, the subpacket was not decoded correctly at the base station. The second subpacket is decoded correctly again, and the ACK_RC is transmitted with the rate control command. The mobile station then sends the next packet at a possibly adjusted rate. This example illustrates the possibility of arbitrarily shifting the mobile station's rate using only rate control commands and not using any authorizations.

Note that in another embodiment, the base station may use rate control with or without previously requested autonomous transmissions. Since there are no transmission requests, although the BS may not know the data requirements, reductions can be used to reduce congestion, and additional capacity can be given when there is excess capacity.

FIG. 13 depicts an example embodiment of a system 100 including dedicated rate control signals and shared rate control signals. A dedicated rate control channel (F-DRCCH) is transmitted from the base station 104 to the mobile station 106 . The F-DRCCH, together with the Forward Acknowledgment Channel (F-ACKCH), has the functions of providing acknowledgment, continuous grants, and performing rate control in substantially the same manner as the above-described F-ACKCH and F-RCCH. A base station may transmit a dedicated rate control channel to each of a plurality of mobile stations. In this embodiment, the mobile station also transmits a shared rate control channel (F-CRCCH). A common rate control channel can be used to simultaneously rate control groups of mobile stations.

Figure 14 depicts an embodiment of a system 100 including a forward extended acknowledgment channel (F-EACKCH). F-EACKCH can replace the acknowledgment channel (ie, the above-mentioned F-ACKCH) and the rate control channel (ie, F-RCCH). According to various aspects of the invention, the functionality of the two channels may be combined into one channel. F-EACKCH is transmitted from one or more base stations 104 to one or more mobile stations 106 . The F-CRCCH may be transmitted together with the F-EACKCH, as described above and described in further detail below. However, the concept of shared rate control is different from that of extended acknowledgment channels, so the two need not be merged. (Here, the F-CRCCH is indicated by a dotted line in FIG. 14).

For example, F-ACKCH may include commands in a 2-bit data pattern (with 4 states). The ACK-continuation information may be combined with the command for data rate increase as the first state. The ACK-continuation information may be combined with the command for data rate reduction as a second state. ACK-STOP may be the third state, and NAK as the fourth state. The four states can be represented by I and Q modulation form constellation diagrams according to commonly known techniques.

15 depicts an example constellation diagram suitable for use on F-EACKCH. This constellation can be used using quadrature amplitude modulation (QAM) techniques, as is known in the art. In another embodiment, any two signals may be used to map two-dimensional commands, as shown.

In this embodiment, 7 points are assigned to various commands. A null transfer (0,0) point is assigned to NAK_HOLD. This may be the most probable transmission order, and therefore, the transmission power and capacity may be maintained by this allocation. As shown, various other commands assigned to points on the circumference include ACK_INCRESE, ACK_HOLD, ACK_DECREASE, NAK_DECREASE, NAK_INCREASE, and ACK_STOP. Each of these commands may be sent as a single QAM modulation symbol. Each command corresponds to a pair of commands sent on analogous sets of F-ACKCH and F-RCCH channels. ACK_INCREASE indicates that the previous subpacket was correctly decoded and that subsequent subpackets can be sent at an increased rate. ACK_HOLD indicates that the previous subpacket was correctly decoded and the subsequent subpacket can be transmitted at the existing rate. ACK_DECREASE indicates that the previous subpacket was correctly decoded and that the subsequent subpacket can be transmitted, albeit at a reduced rate. ACK_STOP indicates that the previous subpacket was correctly decoded, but any previous grant and/or rate control commands are revoked. Mobile stations are only reverted to autonomous transmissions (if applicable).

NAK_INCREASE indicates that the subpacket was not decoded correctly. Subsequent transmissions may be sent at a higher rate (eg, possibly due to relaxed capacity constraints). In one embodiment, the rate control command is sent after the last subpacket transmission. Another embodiment may allow rate-controlled transmissions with NAKs at any time. In a similar form, NAK_DECREASE indicates that the previous subpacket was not decoded correctly and subsequent transmissions must be made at a reduced rate. NAK_HOLD indicates that the previous subpacket was not decoded correctly and subsequent transmissions can be made at the existing rate.

Although those skilled in the art recognize that a NAK_STOP command (or other commands) could be introduced, in the example of FIG. 15 this command is not used. Various schemes for encoding NAK_STOP (detailed above) can also be used with F-EACKCH.

Those skilled in the art will recognize that a variety of constellations may be used, including any command set (or combination thereof), as described herein. Constellation diagrams can be designed to provide various levels of protection (ie, likelihood of correct receipt) for various commands, command sets, or command types.

Figure 16 depicts another constellation suitable for use on F-EACKCH. This example illustrates rate control to remove NAK commands. Various ACK commands include ACK_HOLD, ACK_INCREASE, ACK_DECREASE, and ACK_STOP. For the above reasons, the null command (0, 0) is assigned to NAK. Additionally, it can be seen that the distance between a NAK and any ACK command is equal, and this distance can be set to any value to provide an error probability for a desired NAK.

Various constellations can be designed into command set groups with desired properties. For example, NAK commands may be assigned points relatively close together, ACK commands may be assigned points relatively close together, and the two groups may be separated by a relatively large distance. In this approach, while the probability of confusing one type of command in a group for another type of command in the group may increase, the probability of confusing a group type is correspondingly reduced. Therefore, ACKs are less likely to be misidentified as NAKs and vice versa. If a decrease, increase or hold is misidentified, subsequent rate control commands can be used to compensate. (Note that an increased indication may increase interference to other channels in the system, such as when a decrease or hold is sent.)

Figure 17 depicts a three-dimensional example constellation suitable for use on F-EACKCH. A three-dimensional constellation diagram can be formed using any three signals to indicate the magnitude of each axis. Alternatively, a single signal may be time multiplexed to convey information in one or more dimensions for a first period of time, followed by information in one or more additional dimensions in one or more second dimensions. Those skilled in the art will recognize that this can be extended to any number of dimensions. In one example, QAM signals and BPSK signals may be transmitted synchronously. QAM signals can convey x- and y-axis information, while BPSK signals convey z-axis information. Constellation generation techniques are known in the art.

The example of FIG. 17 further illustrates the concept of combining ACK commands away from NAK commands. Note that the relative distance between ACK_STOP, ACK_DECREASE, ACK_HOLD, and ACK_INCREASE is smaller than the distance between any ACK command and any NAK command (including NAK_HOLD, NAK_INCREASE, and NAK_DECREASE in this example). In this way, the mobile station has a smaller probability of misidentifying an acknowledgment command than a rate command. Those skilled in the art can apply the disclosure herein to form constellations that include any set of commands with the same set of protections for those commands, or with protections assigned in any desired manner.

FIG. 18 depicts an embodiment of a method 750 for processing received transmissions at a base station, including acknowledgments and rate control as used in step 750, as applicable above. Considering that prior to step 750, the base station has received previous requests (if any), made any desired grants, received grants and autonomous transmissions and performed scheduling including these and other factors.

This embodiment of step 750 begins in block 1810 . The base station makes any required applicable grants in accordance with previously performed scheduling. In block 1820, an ACK or NAK command is generated to acknowledge the previous transmission. This acknowledgment command may be merged or combined with commands extending previously granted or rate controlling existing granting commands, including rate control of autonomous transmissions. Any of the techniques described herein may be used for signaling at block 1820, including separate rate control and acknowledgment signals and combined acknowledgment rate control signals.

In block 1830, an ACK_STOP command may be sent to indicate that the mobile station should revert to autonomous mode from the previous authorization. In this embodiment, ACK_STOP can also be used to instruct the mobile station to switch from monitoring the dedicated rate control channel (ie, F-DRCCH) to monitoring the common rate control signal (ie, F-CRCCH). In another embodiment, other commands may be selected to indicate transition from dedicated rate control channel monitoring to shared rate control channel monitoring. Specific commands can be defined for this purpose. The specific command may also be included in the combined channel along with one or more points on the constellation diagram, or the command may be sent by signalling. In block 1840, the one or more base stations provide acknowledgments for subsequent autonomous transmissions. In block 1850, shared rate control is then used to alter the rate of one or more mobile stations monitoring the shared rate control channel. The process can then end.

Figure 19 depicts an embodiment of a method 1900 for responding to shared or dedicated rate control. Method 1900 may be used within a mobile station responsive to a base station using a combination of shared and dedicated rate control as shown above with reference to FIGS. 7 and 18 . The process begins in decision block 1910 . In this instance, dedicated rate control is provided with the authorization. Mobile stations not operating under a license will monitor the shared rate control channel. In another embodiment, licensed mobile stations may also be instructed to follow a common rate control signal, or unlicensed mobile stations may be assigned a dedicated rate control channel. These schemes are not depicted in Figure 19, but in light of the disclosure herein, those skilled in the art will readily employ this embodiment and its modifications using any number of signaling techniques. In decision block 1910 , if the mobile station was operating under previous authorization, then the process proceeds to block 1940 .

At block 1940, the mobile station monitors the grant channel (ie, F-GCH), acknowledgment, and rate control channel (which may be F-ACKCH and F-DRCCH or combined F-EACKCH as described above). In block 1945, if an ACK_STOP command is received, proceed to block 1950. In this embodiment, ACK_STOP is used to designate a reply to an autonomous transmission, as shown in block 1950 . As detailed further below, ACK_STOP also specifies a transition from monitoring a dedicated rate control channel to monitoring a shared rate control channel. In another example, a command other than ACK_STOP may also be used to specify the transition from dedicated to shared rate control channel monitoring, and the command need not be the same as the command used to revert to autonomous transmission. After block 1950, the process may stop. In an example embodiment, method 1900 will be repeated as needed.

In decision block 1945 , if ACK_STOP is not received, proceed to block 1955 . In block 1955, the mobile station may order transmissions in accordance with ACK/NAK, rate control, and/or possibly received grant channel. Subsequently, the process for the current iteration may end.

Returning to decision block 1910, if the mobile station is not currently operating under a previous authorization, proceed to decision block 1915. In decision block 1915, if a grant is received on the grant channel, proceed to block 1920 and transmit in accordance with the received grant, after which the process may stop. Note that in this example, as described above, the grant is used to indicate that the mobile station will monitor the dedicated rate control channel. Thus, in subsequent iterations of method 1900, the mobile station will proceed from decision block 1910 to block 1940, as described above. In further embodiments, alternative techniques for indicating a transition to dedicated rate control monitoring may be used.

In decision block 1915, if no grant is received, the mobile station monitors the shared rate channel, as indicated in decision block 1925. If a shared rate control command is issued, proceed to block 1930 . The mobile station adjusts the rate according to the shared rate control command and continues to transmit autonomously at the revised rate. The process can then be stopped.

If at decision block 1925 a shared rate control command is not received, proceed to block 1935 . The mobile station can continue to transmit autonomously at the current rate. Subsequently, the process can be stopped.

FIG. 20 depicts an alternative embodiment of a method 750 for processing received transmissions, including acknowledgments and rate control suitable for use in step 750 described above. This embodiment illustrates the use of an extended acknowledgment channel (F-EACKCH) to combine acknowledgment and rate control. Consider that prior to step 750, the base station has received any previous requests, made any appropriate grants, received granted and autonomous transmissions, and performed scheduling including these and other factors.

This embodiment of step 750 begins at block 2005 . The base station makes any required grants as applicable, as depicted in block 2010, in accordance with previously performed scheduling. In decision block 2015, an ACK or NAK is determined in response to the previously received transmission. The ACK or NAK will be combined with rate control to provide the combined F-EACKCH detailed below.

If an ACK is to be sent, proceed to decision block 2020 . If rate control including maintaining the current rate (ie ACK-persisting) is desired for the target mobile station (as determined by any scheduling performed within the previous steps), proceed to decision block 2030 . In decision block 2030, if an increase is required, proceed to block 2035 and send ACK_INCREASE on the F-EACKCH. The process can then end. If no increase is required, then it is determined whether a decrease is required at decision block 2040 . If a decrease is required, proceed to block 2045 to transmit ACK_DECREASE on the F-EACKCH. The process can then end. If neither increase nor decrease is required, it can be maintained. Proceed to block 2050 to transmit ACK_HOLD on the F-EACKCH. The process can then end. Note that each of the three ACK commands and the rate control are also used as grants before the extension.

In decision block 2020 , if rate control is not required, ACK_STOP is transmitted on the F-EACKCH, as shown in block 2025 . The process can then end. When ACK_STOP is used by the embodiments depicted in Figures 18-19, eg, where shared and dedicated rate control is used, ACK_STOP is an example of a command that can instruct a mobile station to transition from dedicated to shared rate control monitoring. In this example, ACK_STOP terminates any previous grants, and the mobile station will then be reverted to autonomous transmission.

Returning to decision block 2015, if no ACK is to be transmitted, then it is the turn of the NAK. As mentioned above, there are various schemes for combining rate control and NAK depending on whether the NAK is in response to the last subpacket or not. In other embodiments, those schemes may also be incorporated into the method depicted in FIG. 20 . In this embodiment, if, in decision block 2055, a NAK is not in response to the last subpacket, proceed to block 2060 to transmit NAK_HOLD on the F-EACKCH. As mentioned above, this command indicates that the subpacket was not decoded correctly and that the next subpacket can be transmitted at the current rate. The process can then end.

In decision block 2055, if the NAK response is the last subpacket, proceed to decision block 2065. If rate control is not required, proceed to block 2060 to transmit NAK_HOLD on the F-EACKCH, as described above. Note that in another embodiment, additional commands may also be included. For example, NAK_STOP can be used to send a NAK to a subpacket while revoking the previous authorization. Various other combinations will be recognized by those skilled in the art in light of the disclosure herein.

In decision block 2065, proceed to decision block 2070 if rate control is required. If increment is required, proceed to block 2075 to transmit NAK_INCREASE on F-EACKCH. Otherwise, proceed to block 2085 to transmit NAK_DECREASE on the F-EACKCH. The process can then end. Note that, in this example, the default NAK, ie NAK_HOLD, as indicated by block 2060 is reachable from decision block 2065 . If other embodiments, ie, including NAK_STOP, are used, additional decision paths similar to blocks 2040-2050 above may be used to include other paths to transmit NAK_HOLD.

21 depicts a methodology 2100 for receiving and responding to F-EACKCH. In one embodiment, method 2100 may be used in a mobile station responsive to a base station transmitting according to various methods described above, including those depicted in FIGS. 7 , 18 and 20 . The method begins in block 2110, where the mobile station monitors a grant channel (ie, F-GCH) to determine if a grant has been received.

In block 2120, the mobile station also monitors the F-EACKCH for responses to previously transmitted subpackets. The mobile station then transmits or retransmits according to the ACK or NAK indication on the F-EACKCH. Changes in the transmission rate may also be made in accordance with any STOP, HOLD, INCREASE or DECREASE on the F-EACKCH, as well as any received grants. The process can then end.

Various other embodiments including shared and dedicated rate control are described further below.

A mobile station in soft handoff can monitor shared rate control from all cells in the active pilot set, from a subset thereof, or from the serving cell only. In one example embodiment, each mobile station may increase its data rate only if all F-CRCCH channels from the monitored set of cells indicate an increase in the allowed data rate. This improves interference management. As indicated by this example, the data rates of multiple mobile stations during soft handover may be different due to differences in their active pilot set sizes. F-CRCCH can be used to accommodate more processing gain than F-DRCCH. Thus, for the same transmission power, it must be more reliable.

Consider that rate control can be configured as common rate control (i.e., a single indicator per part), dedicated rate control (dedicated to a single mobile station), or group rate control (one or more mobile stations within one or more groups) . Depending on which rate control mode is selected (this may be indicated to the mobile station through L3 signaling), the mobile station may have different laws of rate adjustment according to the rate control bits, ie, specifically, RATE_INCREASE and RATE_DECREASE. For example, if shared rate control, the rate adjustment is random, and if dedicated rate control, the rate adjustment is deterministic. Various other modifications will be apparent in light of the disclosure herein.

Additionally, in various examples above, it was assumed that rate control is per HARQ channel. That is, when the mobile station receives an acknowledgment or negative acknowledgment after the last subpacket, it only pays attention to the rate control command and determines the rate adjustment for the next transmission on the same ARQ channel. It may not care about rate control commands in retransmissions. Therefore, the base station does not send rate control commands in retransmissions.

For shared rate control or group rate control, alternative laws to the above described laws are foreseen. Specifically, the base station can send the rate control command in the retransmission. Therefore, the mobile station can accumulate rate control commands in retransmissions and apply them to the next packet transmission. In this example, we assume rate control is still per HARQ channel. However, F-ACKCH and F-RCCH are used as two channels with independent operations. These techniques can also be generalized for rate control across all ARQ channels (or a subset thereof).

Grant, Acknowledgment, and Rate Control Active Pilot Sets

FIG. 22 depicts an example embodiment of a system 2200. System 2200 is suitable for use as system 100 as depicted in FIG. 1 . One or more base stations 104A-104Z are in communication with a base station controller (BSC) 2210 . The base station to BSC connection may be wired or wireless utilizing any of a variety of protocols as is known in the art. One or more mobile stations 106A-106N may be deployed and may move within or across the coverage area of the BSC 2210 and its connected base station 104. The mobile station 106 communicates with the base station using one or more communication formats, examples of which are defined in the previously described standards. For example, mobile station 106A is shown in wireless communication with base stations 104A and 104M, and base station 106N is shown in communication with base stations 104M and 104Z.

The BSC 2210 includes active pilot sets 2220A-2220N, and each mobile station that the BSC communicates with corresponds to one of the pilot sets. Various handover and registration schemes for determining which mobile station is within the coverage area of system 2200 at any given time are known in the art. Each mobile station 106 has an active pilot set 2230 corresponding to one of the active pilot sets 2220 in the BSC. The active pilot set 2220 in the BSC 2210 is the same as the active pilot set 2230 in the corresponding mobile station 106 . In an example embodiment, once the BSC decides to change the active pilot set, it indicates the change to the mobile station at a corresponding operating time. At designated operating times, both the BSC and the mobile station update their active pilot sets. In this way, the two active pilot sets remain synchronized. In another embodiment, if the synchronization technique is not used, the two sets may not be synchronized until signaling or some other mechanism delivers a valid pilot set update. The active pilot set 2220 or 2230 may be stored in memory using any of a variety of techniques, as is known in the art. In the current system, and in the example embodiment, the BSC determines the active pilot set for each mobile station. Typically, in other embodiments, the mobile station or the BSC may determine the active pilot set in whole or in part. In this case, a change in one is indicated to the other in order to keep the active pilot sets synchronized.

In a conventional CDMA cellular system, the effective pilot set for a mobile station is generated as follows. The mobile station reports the signal strength of neighboring base stations to the base station controller via one or more base stations. In one example embodiment, this reporting is done by Pilot Strength Measuring Messages (PSMMs). The BSC may then use the reported pilot signal strength and other criteria to determine the mobile station's active pilot set. The active pilot set is indicated to the mobile station via one or more base stations.

In an example embodiment, such as a 1xEV-DV system, a mobile station can autonomously select its serving cell by transmitting its channel quality indicator (CQI), which uses a coverage sequence specific to that serving cell. To switch cells, the mobile station simply changes the coverage sequence. Various other methods for autonomous selection of base stations will be apparent to those skilled in the art. Examples include sending a message to a previously selected base station, a newly selected base station, or both.

In another embodiment, for example, the active pilot set in a 1xEV-DV type system in which a mobile station can autonomously select a base station can be identified at the base station by storing the most recently selected base station and other monitored base stations meeting certain criteria. produce. The mobile station may also send its generated active pilot set to the base station controller to assist in selecting additional active pilot sets, such as grant, acknowledgment and rate control active pilot sets described below.

The mobile station can combine signals from multiple base stations in the active pilot set when appropriate. For example, FCH (Fundamental Channel) or DCCH (Dedicated Control Channel), examples of the various standards listed above, may be transmitted from an active pilot set comprising multiple base stations and combined at the mobile station. In these instances, the effective set of pilots associated with an instance signal is typically determined by the BSC or other central processing location.

In the example IxEV-DV embodiment however, the F-PDCH is usually sent from a single base station, as described above. In this way, the mobile station does not combine a plurality of F-PDCH signals. The reverse link signals may be combined in one or more base stations. Portion consolidation is particularly suitable, where multiple portions (or other co-located portions) of a single base station may be consolidated. Due to suitability for high bandwidth backhaul, it is conceivable that different base stations can also combine received signals. In example cellular systems deployed today, selective combining is typically used, where each separately located base station decodes the received transmission (possibly as part of the softer combining), and responds depending on whether the separate decoding was successful. If successful, the received transmission can be forwarded to the BSC (or other destination of the received packet), and an acknowledgment can be transmitted to the mobile station. The transmission is considered successful if any receiver decodes the packet correctly. The principles disclosed here can be used with any forward or reverse link combining strategy.

An extended effective pilot set suitable as effective pilot set 2220 or 2230 is clearly depicted in FIG. 23 . The various active pilot sets are illustrated as ovals to illustrate the base stations contained in the active pilot sets. Overlapping or enclosing ovals indicate base stations that are commonly included in more than one type of active pilot set (ie, they can be viewed as a Venn diagram). The example extended effective pilot set 2230 or 2230 illustrated in this FIG. 23 includes an FCH type effective pilot set 2310 (an alternative example includes a mobile station generated effective pilot set as described above for the 1xEV-DV F-PDCH channel). Active pilot set 2310 may be used as a function of a conventional active pilot set, ie, for receiving and combining forward or reverse link signals at a mobile station or base station group (and/or portion), respectively. In the description here, the group of effective pilot sets included in the extended effective pilot set 2220 or 2230, which is further detailed below, can also be configured as an independent effective pilot set, which is obvious to those skilled in the art. obviously.

Acknowledgment Active Pilot Set 2320 identifies the base station from which the Forward Acknowledgment Channel will be transmitted. A base station in the validated active pilot set 2320 may transmit a validated command to mobile stations associated with the validated pilot set, examples of which are detailed above. Base stations in the acknowledgment active pilot set may not need to transmit acknowledgment commands all the time. The associated mobile station may monitor acknowledgment channels from those base stations in the acknowledgment active pilot set. In an example embodiment, the mobile station does not need to monitor acknowledgment channels from base stations outside the set of acknowledgment active pilots, which may minimize complexity and/or power consumption in the mobile station. By efficiently maintaining an acknowledgment active pilot set, signaling or other techniques for identifying required acknowledgment channels can be reduced, thereby increasing efficient use of shared resources.

As examples of possible efficiency gains, other point-to-point signaling methods for determining which base station transmits a particular signal to a mobile station may be considered. This point-to-point signaling may require more power or resource allocation. Another advantage is the simple and efficient allocation of Walsh channels for transmission of different signaling. Those skilled in the art will recognize that in many cases Walsh tree application can be a factor in determining capacity.

In the example of FIG. 23, the validated active pilot set is illustrated as a subset of the active pilot set 2310, although this is not required. The two sets may be equal and, depending on how the effective pilot set 2310 is defined, the validation effective pilot set 2320 may be a superset of the effective pilot set 2310.

Granted Valid Pilot Set 2340 is illustrated as a subset of Confirmed Valid Pilot Set 2320 . Again, this is just an example. The set of grant valid pilots can be used to indicate which base stations may transmit grants to associated mobile stations. In this way, the associated mobile station can use the set of authorized active pilots to identify authorized channels from which authorization can come, and thus can limit its monitoring to those channels, possibly adding complexity and/or Power consumption is minimized. By efficiently maintaining the set of validated pilots, signaling or other techniques for identifying required licensed channels can be reduced, which increases efficient use of shared resources. The overhead from signaling can be reduced by employing the licensed active pilot set 2340 . As an example of possible additional effective gain, consider an alternative technique in which the number of authorized base stations that can authorize is unlimited. A base station with a relatively weak connection to the mobile station may not have an accurate picture of channel conditions close to the mobile station. Grants from such base stations can create system performance problems for that base station (and its respective connected mobile stations), if grants are made in this situation.

The authorized channel valid pilot set can be switched autonomously by the mobile station. As described above, a mobile station can autonomously change serving cells by switching its CQI coverage sequence. There are other schemes for updating the authorized active pilot set when the mobile station switches its serving base station autonomously. In the case that the licensed channel valid pilot set size is set to 1, the mobile station can update the licensed channel valid pilot set when it changes in the serving cell, and consider a single licensed base station as the serving cell. Another option, not limited to the size of the authorized active pilot set, is to set the authorized active pilot set to an empty set, and the mobile station waits for a message to include one or more new base stations in the authorized active pilot set. Alternatively, each base station may have a predetermined or indicated list of other authorized base stations to be used in selecting the respective base station. Various other schemes can also be used.

Upon learning of a new mobile station within its coverage area (i.e., receiving a new sequence of CQI messages), the base station can signal the BSC to which the mobile station has autonomously reselected, so that the BSC can update its copy of the mobile station's active pilot set accordingly . A mobile station may also send messages to a BSC via one or more base stations. In general, the concept of a serving base station may not be related to the concept of an authorized active pilot set (although in general the authorized active pilot set may include a serving base station). For example, signaling can be used to instruct the mobile station to monitor authorized channels from a specific list of base stations, while the mobile station can freely select its serving base station (ie, the base station that sends the F-PDCH) arbitrarily.

Rate control active pilot set 2350 may also be illustrated as a subset of acknowledgment active pilot set 2320 . It is illustrated as overlapping with the set of authorized active pilots 2340 . Again, this is just an example. Various other embodiments are detailed below. The set of rate control active pilots can be used to indicate which base station can transmit rate control commands or channels to the associated mobile station. In this way, the associated mobile station can use the rate control active pilot set to identify the rate control channel from which the authorization can come, and in this way can limit its monitoring of those channels, possibly to the complexity and/or power consumption in the mobile station. minimize. By efficiently maintaining an acknowledged active set of pilots, signaling or other techniques for identifying required rate control channels can be reduced, which increases efficient use of shared resources. Note that the combined acknowledgment/rate control channel, as detailed above, can also be used with the active pilot set described here. Modifications to the various embodiments described above will be readily apparent to those skilled in the art in light of the disclosure herein.

In FIG. 23 , rate control active pilot set 2350 is shown as a subset of acknowledgment active pilot set 2320 and overlaps with authorized active pilot set 2340 . Again, this is just an example. As an illustration, any base station capable of receiving and possibly decoding a reverse link transmission can be made to attempt to decode and transmit the appropriate acknowledgment command in response. However, the channel conditions between the mobile station and one or more of these base stations may be so poor that those base stations are not required to authorize or rate control the mobile station. In this manner, a relatively large set of acknowledgment active pilots 2320 may be used.

Other base stations in the larger acknowledgment active pilot set 2320 may be configured such that they are capable enough to perform rate control, but granting may not be desired (e.g., weaker base stations may not be sufficiently aware of The effect of the authorization to the base station with stronger performance). Other factors may also come into play. For example, grants can consume significant forward link overhead. Relatively weaker base stations can still perform rate control without using the excess power required for a good transmission grant. Rate control generally requires fewer bits than grants, examples of which are described above. Also, the rate control loop can be more fault-tolerant due to the speed-up adjustments being made, and the loop is self-correcting. Depending on its magnitude and magnitude variations introduced by errors, grants can cause large variations in the rate in the mobile station. System capacity reduction may be more severe in this case. Thus, in cases such as this one, it may be desirable to use a rate control active pilot set 2350 that is separate from, or partially overlaps with, the authorized active pilot set 2340 . Based on the disclosure herein, those skilled in the art will readily employ various techniques for allocating base stations for various active pilot sets.

FIG. 24 depicts an example of an alternate extended active pilot set 2220 or 2230. In this example, the set of rate control active pilots 2350 is a superset of the set of authorized active pilots 2340 . Thus, each base station in the granted active pilot set can also use rate control, if desired. Some base stations in the rate control active pilot set 2350 are not authorized to transmit grants. One reason for comparing overlapping grants and effective pilot sets for rate control is that some base stations may not be configured for scheduling, or not configured for rate control. Other reasons can be found that limit the base station to only schedule grants without rate control. For example, in some instances, the nature of the data being transferred can make it more amenable to authorization methods that change rapidly. Also, some data could make it better applicable to the rate control method. However, the example of FIG. 24 illustrates the authorized active pilot set 2340 as a subset of the rate control active pilot set 2350 . Those skilled in the art will recognize various effective pilot set structures in accordance with the disclosure herein.

FIG. 25 depicts another example of an alternative extended effective pilot set 2220 or 2230. In this example, there is no rate control active pilot set 2350. Additionally, the rate control active pilot set 2350 can be used, but it is empty. In this case, at least resource allocation to associated mobile stations is done by grant scheduling only. There is no rate control at this time. Various factors can lead to this configuration, such as the nature of the data, or lack of support for rate control in the network or in the mobile station. In this example, the validated active pilot set 2320 is a superset of the authorized active pilot set 2340 .

FIG. 26 depicts another example of an alternative extended effective pilot set 2220 or 2230. In this example, no valid pilot set 2340 is authorized. Additionally, the authorized active pilot set 2340 may be configured, but empty. In this case, the allocation of resources, at least for the associated mobile stations, is done by rate control only. Scheduling is not authorized at this time. Various factors can lead to this configuration, such as the nature of the data, or lack of support for grant scheduling in the network or in the mobile station. In this example, the validation active pilot set 2320 is a superset of the rate control active pilot set 2350 .

Note that the size and structure of the active pilot set can be continuously updated as needed to yield various scheduling or rate control resource allocation implementations. The active pilot set can be updated in response to characteristics of the data being transmitted. For example, as previously explained, grant scheduling is desirable when rapid increases or decreases in data rates are required (ie, bursts, relatively large data volumes, or particularly time-sensitive data). Or, for steady streams of data, rate control can provide the desired control with lower overhead. By limiting multiple allocation methods to base stations within each active pilot set, reverse link transmissions can be efficiently controlled, as detailed herein, without overly interfering with neighboring cells. At the same time, flexibility is maintained to support multiple QoS levels and the like.

In adjacent systems, one vendor may use a different feature set than another. For example, a provider may not support authorized scheduling. Or, a provider may not support rate control. The capabilities of multiple base station configurations can be subsumed by including them in each active pilot set.

An active pilot set may include any number of base stations, including zero. Another not-illustrated solution is to include an extended effective pilot set 2220 that includes an acknowledgment effective pilot set 2320 but does not include a grant or rate control active pilot set (or, optionally, an empty grant and rate control active pilot set). or 2230. In this case, the mobile station is only effectively classified as autonomously transmitting. The mobile station can conserve resources and reduce overhead by suppressing any required transmission requests when the authorized active pilot set is empty. Any combination of grant, acknowledgment, and rate control active pilot sets can be used within the scope of the present invention.

27 depicts an example methodology 2700 for generating an extended effective pilot set, such as effective pilot set 2220 or 2230. In this example, the method 2700 may be performed in the BSC 2210, although those skilled in the art will recognize that the method 2700 or portions thereof may suitably be performed in the mobile station 106 or the base station 104.

The process begins at block 2705, where a pilot signal strength measurement message (ie, PSMM) to the base station is received from the mobile station. Note that in alternative embodiments, other base station measurements, or other information related to extended active pilot set selection may be received at the BSC.

In decision block 2710, if the received information indicates that the base station meets the criteria for selection within the authorized active pilot set, proceed to block 2715. Otherwise, proceed to decision block 2725. Various criteria, including signal strength, can be used to make the determination. Examples of other factors that may be included are described above.

In block 2715, the base station has satisfied the rules, so the base station is added to the set of authorized active pilots for the corresponding mobile station. In block 2720, a message or signal is sent to the mobile station indicating that it should add the base station to its authorized active pilot set. Note that blocks 2715 and 2720 may be omitted if the base station is already in the authorized active pilot set (details not shown).

If, in decision block 2725, the base station is in an authorized active pilot set, proceed to block 2730 to remove it because it no longer meets the criteria. In block 2735, a message or signal is sent to the mobile station indicating that the corresponding base station should be removed from the authorized active pilot set.

In decision block 2740, if the received information indicates that the base station meets the criteria selected in the rate control active pilot set, proceed to block 2745. Otherwise, proceed to decision block 2755. Various criteria, including signal strength, can be used to make the determination. Examples of other factors that may be included are described above.

In block 2745, the base station has met the criteria, so the base station is added to the rate control active pilot set of the corresponding mobile station. In block 2750, a message or signal is sent to the mobile station indicating that the mobile station should add the base station to its rate control active pilot set. Note that blocks 2745 and 2750 may be omitted if the base station is already in the rate control active pilot set (details not shown).

If, in decision block 2755, the base station is in the rate control active pilot set, proceed to block 2760 to remove it because it no longer satisfies the criteria. In block 2765, a message or signal is sent to the mobile station indicating that the corresponding base station should be removed from the rate control active pilot set.

In decision block 2770, if the received information indicates that the base station meets the criteria selected in the validated pilot set, proceed to block 2775. Otherwise, proceed to decision block 2785. Various criteria, including signal strength, can be used to make the determination. Examples of other factors that may be included are described above.

In block 2775, the base station has met the criteria, so the base station is added to the corresponding mobile station's confirmed active pilot set. In block 2780, a message or signal is sent to the mobile station indicating that the mobile station should add the base station to its confirmed valid pilot set. Note that blocks 2775 and 2780 may be omitted if the base station is already in the valid pilot set (details not shown).

If, in decision block 2785, the base station is in the Validated Pilot Set, proceed to block 2790 to remove it because it no longer meets the criteria. In block 2795, a message or signal is sent to the mobile station indicating that the corresponding base station should be removed from the confirmed valid pilot set.

The process depicted for method 2700 can be repeated for multiple base stations for each of multiple mobile stations. In another embodiment, various subsets of the illustrated steps may be omitted. For example, if rate control or grant scheduling is not supported, the corresponding steps may be removed. Method steps may be interchanged without departing from the scope of the present invention.

28 depicts a methodology 2800 for transmitting in accordance with an extended active pilot set. The process begins at block 2810. Depending on the communication system or standard being used, each mobile station within the system makes measurements of the number of base stations surrounding them. System measurements may also be made at the various base stations used throughout the system. The measurements can be forwarded to a central processing location such as a BSC or multiple destinations for distributed computing.

In block 2815, an extended effective pilot set may be generated and updated for each mobile station in the system. Measurements made and other criteria, examples of which are described above, can be used to determine the extended effective pilot set. In an example embodiment, an acknowledgment active pilot set, a grant active pilot set, and a rate control active pilot set are included in the extended active pilot set. In other embodiments, other selected active pilot sets may be used.

In block 2820, the active pilot set information, such as the updated extended active pilot set, is indicated to the appropriate target. In one example, the active pilot set is indicated to each mobile station from the BSC through one or more base stations. In another embodiment, if some or all of the extended active pilot set is determined elsewhere, such as at the mobile station or base station, this determination is then transmitted to the BSC or other base station as needed.

In block 2825, the base station is signaled which channels to transmit to the plurality of mobile stations based on the extended active pilot set. For example, a base station that joins a mobile station's authorized active pilot set will be signaled that the base station can issue applicable grants to each mobile station. Of course, the base station needs to be signaled only when its state changes.

In block 2830, an acknowledgment is sent, by the base station, to mobile stations in the system based on the acknowledgment valid pilot set. Transmission of the acknowledgment command or signal may be made according to any of the examples described above, as well as any other technique known in the art.

In block 2835, grants are sent by the base station to mobile stations in the system based on the grant valid pilot set. Authorized transmissions may be made according to any of the examples above, as well as any other techniques known in the art.

In block 2840, rate control commands are sent by the base station to mobile stations in the system based on the rate control active pilot set. Transmission of rate control commands or signals may be made according to any of the above examples, as well as any other technique known in the art.

In block 2845, each mobile station monitors the channel according to each extended active pilot set. In block 2850, the mobile station transmits in response to the command received on the monitored channel.

29 depicts an example methodology 2900 for communicating with an extended active pilot set within a mobile station (eg, mobile station 106). The process begins in block 2910, where the mobile station measures surrounding base stations. Parameters used for neighboring base station measurements may be sent from the base station or BSC to the mobile station. In another embodiment, the extended active pilot set may be generated without mobile generated measurements.

In block 2915, the mobile station transmits active pilot set information to the BSC (or other active pilot set processing device, such as a base station or other central processing unit). The active pilot set may include the measurements made in block 2910. Any active pilot set selection made in the mobile station may also be transmitted if necessary. For example, in a 1xEV-DV system, a mobile station can autonomously select a serving base station. This selection can be issued from the base station or from the mobile station itself.

As described above with reference to Figures 27-28, the BSC or other means may update the extended active pilot set based on mobile station generated information and other criteria. If an extended active pilot set revision is made, it may be indicated to the corresponding mobile station. In decision block 2920, if an active pilot set update is received, proceed to block 2925 to alter each active pilot set or sets of active pilots. Proceed to decision block 2930.

In decision block 2930, if there are one or more base stations in the acknowledgment active pilot set, then the acknowledgment channel from each base station is monitored, as shown in block 2935. Then proceed to decision block 2940.

In decision block 2940, if there are one or more base stations in the authorized active pilot set, then the authorized channels from each base station are monitored, as shown in block 2945. Proceed to decision block 2950.

In decision block 2950, if there are one or more base stations in the rate control active pilot set, the rate control channel from each base station is monitored, as shown in block 2955. Then proceed to block 2960.

In decision block 2960, the mobile station may adjust its transmission rate in response to any grant or rate control commands it may have received on the monitored channel. The mobile station may transmit new packets or retransmit previously transmitted packets in response to any acknowledgment commands or messages on the monitored channel. The process can then end.

30 depicts an example message suitable for notifying an extended active pilot set of changes. These messages can be consumed by any of the previously described methods. It will be apparent to those skilled in the art that the messages depicted in Figure 30 are illustrative only. The message can be fixed length or variable length. The fields of this message can be of any size. Messages are available in a variety of modulation formats. Messages may be contained within or include other messages used in the system. A number of message types are known in the art and may be suitable for use in light of the disclosure herein.

Add message 3000 may be used to indicate that the base station should be added to the extended active pilot set. Note that this message can be transmitted to or from any two devices. In an example embodiment, the BSC may generate messages for transmission to one or more mobile stations via one or more base stations. Field 3005 of the message indicates that the message is an add message. Field 3010 identifies the mobile station associated with the Active Pilot Set and may be used to identify receipt of the message. Field 3015 includes an identifier associated with the base station to be joined. In another message embodiment, more than one base station may be added at the same time, so field 3015 will include one or more base station identifiers. Field 3020 may be used to indicate the active set of pilots that the base station should join. An identifier may be associated with each valid pilot set within the extended valid pilot set (i.e., one identifier corresponds to the authorized valid pilot set, another identifier corresponds to the rate control valid pilot set, and another corresponds to the confirmed valid pilot set set, etc.).

Delete message 3030 may be used to indicate that the base station should be deleted from the extended active pilot set. Similar to message 3000, there is field 3035 for identifying the message (which may also include other header information). Field 3040 identifies the mobile station associated with the Active Pilot Set and may be used to identify receipt of the message. Field 3045 includes an identifier associated with the base station to be deleted. In another message embodiment, more than one base station may be deleted at the same time, so field 3045 will include one or more base station identifiers. As with message 3000, field 3050 may be used to indicate the active set of pilots that the base station will join.

List message 3060 may be used to immediately indicate the entire set of active pilots. For example, any active pilot set included in the extended active pilot set may be defined by the list message. A list message may be sent when empty to clear the active pilot set. Similar to messages 3000 and 3030, there is field 3065 for identifying the message (which may also include other header information). Field 3070 identifies the mobile station associated with the Active Pilot Set and may be used to identify receipt of the message. Fields 3075A-3075N include identifiers associated with the N base stations to be included in the active pilot set. As with messages 3000 and 3030, field 3080 may be used to identify the set of active pilots defined by the list of base stations.

It should be noted that in all the embodiments described above, method steps may be interchanged without departing from the scope of the present invention. The description disclosed herein refers in many cases to signals, parameters and processes associated with a IxEV-DV system, but the scope of the invention is not limited thereto. Those skilled in the art will readily apply the principles herein to a variety of other communication systems. These embodiments and other modifications will be apparent to those skilled in the art.

Those of skill in the art would realize that information and signals may be represented by any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips referred to in the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill in the art would further recognize that the various illustrative logical blocks, modules, circuits, and algorithm steps associated with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations thereof. To clearly illustrate this alternative to hardware and software, various illustrative elements, blocks, modules, circuits, and steps have been described above in terms of their functionality. Whether the functionality is implemented as hardware or software is determined by application-specific and design constraints imposed on the overall system.

The various illustrative logical blocks, modules, and circuits related to the embodiments disclosed herein may be implemented by a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other Implementation or execution by programmable logic devices, discrete gate or transistor logic, discrete hardware elements, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in another aspect, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, eg, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other configuration.

The steps of a method or algorithm described in association with the embodiments disclosed herein may be implemented directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable hard disk, CD-ROM or any form of storage medium known in the art. An illustrative storage medium is coupled to a processor that can read information from, and write information to, the storage medium. On the other hand, the storage medium is integral to the processor. The processor and storage medium can be placed in an ASIC. The ASIC can be placed in the user premises. On the other hand, the processor and the storage medium may be placed in the client as separate elements.

The above provides a description of the disclosed embodiments to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not limited to the embodiments illustrated herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A device for monitoring messages comprising: a processor for generating a list comprising zero or more identifiers associated with the first station, each identifier identifying a plurality of one of the second communication stations; and a transmitter for transmitting a second message to the first station, wherein the processor also generates the second message including zero or more identifiers from the list; The second message instructs the first station to delete an identifier from a list of identifiers stored within the first station. 2. The apparatus of claim 1, wherein the list associated with the first station is generated according to one or more predetermined criteria. 3. The apparatus of claim 1 , further comprising a receiver for receiving measurements of a second station, wherein the processor includes all of the information in the list associated with the first station. An identifier associated with said second station, said list associated with said first station is generated according to said received measurements and according to one or more predetermined criteria. 4. The apparatus of claim 1, wherein the second message identifies a list of identifiers stored within the first station. 5. The apparatus of claim 1 , further comprising a transmitter for transmitting a third message to a second station identified in the list associated with the first station, the third message authorizing The second station transmits the first message to the first station. 6. An apparatus for monitoring messages comprising: a processor for generating a list comprising zero or more identifiers associated with the first station, each identifier identifying a plurality of one of the second communication stations; a transmitter for transmitting a second message to the first station, wherein the processor further generates the second message including zero or more identifiers from the list; wherein the The second message instructs the first station to add an identifier to a list of identifiers stored within the first station. 7. A method for monitoring messages comprising: generating a list comprising zero or more identifiers, the list being associated with the first station, each identifier identifying one of the plurality of second stations for sending the first message to the first station one; and transmitting a second message to the first station, the second message including zero or more of the identifiers in the list; Wherein, the second message instructs the first station to delete an identifier from a list of identifiers stored in the first station. 8. The method of claim 7, further comprising storing said identifier from said second message within said first station. 9. The method of claim 7, further comprising transmitting a third message to a second station identified in the list associated with the first station, the third message authorizing the second station to transmitting the first message to the first station. 10. A method for monitoring messages comprising: generating a list comprising zero or more identifiers, the list being associated with the first station, each identifier identifying one of the plurality of second stations for sending the first message to the first station one; and transmitting a second message to the first station, the second message including zero or more of the identifiers in the list; Wherein the second message instructs the first station to add an identifier to a list of identifiers stored in the first station.

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