CN101185278B - Method and device for high-rate data transmission in wireless communication - Google Patents

Abstract

Techniques for using multiple carriers to significantly improve transmission capacity are described. For multi-carrier operation, a terminal receives an assignment of multiple Forward Link (FL) carriers and at least one Reverse Link (RL) carrier. The carriers may be arranged in at least one group, each group including at least one FL carrier and one RL carrier. The terminal may receive packets on the FL carriers in each group and may send acknowledgements for the received packets via the RL carriers in the group. The terminal may send Channel Quality Indication (CQI) reports for the FL carriers in each group via the RL carriers in that group. The terminal may also send data on the RL carrier. The terminal may send designated RL signaling (e.g., for initiating a call) on the primary RL carrier and may receive designated FL signaling (e.g., for call setup) on the primary FL carrier.

Description

Method and device for high-rate data transmission in wireless communication

Claiming Priority Based on 35 U.S.C. §119

This patent application claims priority to Provisional Application No. 60/666,461, filed March 29, 2005, entitled "METHODAND APPARATUS FOR HIGH RATE DATA TRANSMISSION INWIRELESS COMMUNICATIONS," which is assigned to the assignee of this application , which is hereby incorporated into this application by reference.

technical field

The present disclosure relates generally to communications, and more particularly to techniques for high-rate data transmission.

Background technique

Wireless communication systems are widely used to provide various communication services such as voice, packet data, broadcast, messaging, and so on. These systems may be multiple-access systems capable of supporting communication for multiple users by sharing available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems.

Data usage on wireless communication systems also continues to grow due to the growing number of users and the emergence of new applications with higher data requirements. However, a given system usually has a limited transmission capacity, which is determined by the system design. Large increases in transmission capacity are typically achieved by deploying new generation systems or new designs of systems. For example, the transition of cellular systems from second generation (2G) to third generation (3G) has provided significant improvements in data rates and features. However, new system deployments are capital intensive and often complex.

Therefore, there is a need in the art for a technique capable of improving the transmission capacity of a wireless communication system in an efficient and cost-effective manner.

Contents of the invention

This document describes techniques for significantly improving transmission capacity using multiple carriers on the forward and/or reverse links. These techniques can be used in various wireless communication systems, eg, cdma2000 systems. These techniques may provide several advantages since only relatively minor changes are made to existing channel structures designed for single carrier operation.

According to one embodiment of the invention, an apparatus is described that includes at least one processor and a memory. The processor receives an assignment of a plurality of forward link (FL) carriers and at least one reverse link (RL) carrier. The processor then receives data transmissions on one or more of the plurality of FL carriers.

According to another embodiment of the present invention, a method is provided wherein an assignment to a plurality of FL carriers and at least one RL carrier is received. Data transmissions are then received on one or more of the plurality of FL carriers.

According to another embodiment of the present invention, an apparatus is described, which includes: means for receiving assignments to a plurality of FL carriers and at least one RL carrier; Multiple modules that receive data transfers.

According to another embodiment of the present invention, an apparatus comprising at least one processor and a memory is described. The processor obtains acknowledgments for packets received on a plurality of data channels (e.g., F-PDCH), channelizes the acknowledgments for the data channels with an orthogonal code assigned to each data channel to generate the data channel and generating modulation symbols of an acknowledgment channel (eg, R-ACKCH) based on the symbol sequences of the plurality of data channels.

According to another embodiment of the present invention, a method is provided wherein acknowledgments are obtained for packets received on a plurality of data channels. The acknowledgments for each data channel are channelized using an orthogonal code assigned to the data channel to generate a sequence of symbols for the data channel. Modulation symbols for an acknowledgment channel are generated based on the symbol sequences of the plurality of data channels.

According to another embodiment of the present invention, an apparatus is described comprising: means for obtaining an acknowledgment for a packet received on a plurality of data channels; for using an orthogonal code pair assigned to each data channel means for channelizing the acknowledgment of the data channel to generate a sequence of symbols for the data channel; and means for generating modulation symbols for an acknowledgment channel based on the sequence of symbols for the plurality of data channels.

According to another embodiment of the present invention, an apparatus comprising at least one processor and a memory is described. The processor obtains complete channel quality indicator (CQI) reports for a plurality of FL carriers, each complete CQI report indicating received signal quality for one FL carrier. The processor sends the complete CQI report for the plurality of FL carriers on a CQI channel (eg, R-CQICH) at different time intervals.

According to another embodiment of the present invention, a method is provided wherein complete CQI reports for multiple FL carriers are obtained, each complete CQI report indicating the received signal quality of one FL carrier. The complete CQI report for the plurality of FL carriers is sent on a CQI channel at different time intervals.

According to another embodiment of the present invention, an apparatus is described, which includes: a module for obtaining complete CQI reports for multiple FL carriers, each complete CQI report indicating the received signal quality of one FL carrier; and for means for sending said complete CQI report for said plurality of FL carriers on a CQI channel at different time intervals.

According to another embodiment of the present invention, an apparatus comprising at least one processor and a memory is described. The processor operates in a control-hold mode that allows the transmission of a gated pilot, receives a data channel (e.g., P-PDCH) transmitted on the forward link in the control-hold mode, and if on the reverse link no other transmissions are being sent on the way, send a gated pilot on the reverse link, and if there is a transmission being sent on the reverse link, send a gated pilot on the reverse link Full pilot.

According to another embodiment of the present invention, a method is provided wherein the terminal operates in a control-hold mode that allows the transmission of a gated pilot. In the control-hold mode, a data channel sent on the forward link is received. The gating pilot is sent on the reverse link if no other transmissions are being sent on the reverse link. A full pilot is sent on the reverse link if a transmission is being sent on the reverse link.

According to another embodiment of the present invention, an apparatus is described comprising: means for operating in a control-hold mode allowing transmission of gated pilots; means for sending the gated pilot on the reverse link when no other transmission is being sent on the reverse link; means for sending a full pilot on the reverse link when a transmission is being sent on the reverse link.

Various aspects and embodiments of the invention are described in more detail below.

Description of drawings

Figure 1 shows a wireless communication system.

FIG. 2 shows exemplary data transmission on the forward link in cdma2000.

Figure 3 shows an exemplary multi-carrier structure.

Figure 4A shows the R-ACKCH structure in cdma2000 Revision D.

Figures 4B and 4C illustrate new R-ACKCH structures that can support up to three and seven R-ACKCHs for multiple FL carriers, respectively.

Figure 5A shows the R-CQICH structure in cdma2000 Revision D.

Figure 5B shows a new R-CQICH structure that can support multiple FL carriers.

6A-6E illustrate exemplary transmissions on the new R-CQICH.

Figure 7 shows the transmission of full pilot and gated pilot on R-PICH.

FIG. 8 illustrates processing performed by a terminal for multi-carrier operation.

Figure 9 shows the process for sending an acknowledgment.

Figure 10 shows a process for sending a CQI report.

Figure 11 shows a process for reducing pilot overhead in multi-carrier operation.

Fig. 12 shows a block diagram of a base station and a terminal.

Detailed ways

As used herein, the term "exemplary" is used to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" should not be construed as preferred or superior to other embodiments.

FIG. 1 shows a wireless communication system 100 having multiple base stations 110 and multiple terminals 120 . A base station is typically a fixed station that communicates with the terminals and may also be called an access point, a Node B, a base transceiver subsystem (BTS) and/or some other terminology. Each base station 110 provides communication coverage for a particular geographic area 102 . The term "cell" can refer to a base station and/or its coverage area depending on the context in which the term is used. To improve system capacity, the base station coverage area can be divided into multiple smaller areas, eg, three smaller areas 104a, 104b, and 104c. The term "sector" can refer to a fixed station and/or its coverage area that serves a smaller area, depending on the context in which the term is used. For a sectorized cell, the base station typically serves all sectors of the cell. The transmission techniques described herein can be used in systems with sectorized cells as well as systems with unsectorized cells. For simplicity, in the following description, the term "base station" is used generically for a fixed station serving a sector as well as a fixed station serving a cell.

Terminals 120 are generally dispersed in the system, and each terminal may be fixed or mobile. A terminal may also be called a mobile station, user equipment or some other terminology. A terminal may be a cellular phone, a personal digital assistant (PDA), a wireless device, a handheld device, a wireless modem, and so on. At any given moment, a terminal may communicate with one or more base stations on the forward and/or reverse links. The forward link (or downlink) refers to the communication link from the base station to the terminal, and the reverse link (or uplink) refers to the communication link from the terminal to the base station.

A system controller 130 is coupled to base stations 110 and provides coordination and control for these base stations. System controller 130 may be a single network entity or a combination of network entities.

The transmission techniques described herein may be used in a variety of wireless communication systems such as CDMA, TDMA, FDMA, and OFDMA systems. A CDMA system may implement one or more radio technologies such as cdma2000, Wideband-CDMA (W-CDMA), and so on. cdma2000 covers IS-2000, IS-856, IS-95 and other standards. A TDMA system can implement a radio technology such as Global System for Mobile Communications (GSM). The various wireless technologies and standards are known in the art. W-CDMA and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 is described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). Both 3GPP and 3GPP2 documents are publicly available. For clarity, the transmission techniques are described below specifically for a cdma2000 system, which may be a "CDMA 1x-EVDV", "CDMA1x", "CDMA 1x-EVDO" and/or a "1x" system.

cdma2000 defines a variety of data and control channels that support data transmission on the forward and reverse links. Table 1 lists some of the data and control channels used for the forward and reverse links and provides a short description of each channel. In the description herein, the prefix "F-" indicates the channel used for the forward link and the prefix "R-" indicates the channel used for the reverse link. In 2004 from the Telecommunications Industry Association "TIA/EIA IS-2000.2 Physical Layer Standard for cdma2000 Spread Spectrum Systems, Release D" (hereinafter referred to as TIA/EIA IS-2000.2) and "TIA/EIA 2000.3 Medium Access Control ( The channels described above are described in detail in "MAC) Standard for cdma2000 Spread Spectrum Systems, Release D" (hereinafter referred to as TIA/EIA IS-2000.3), both standards are publicly available. cdma2000 Revision D is also known as IS-2000 Revision D, or "Rev D" for short. The data and control channels are also described in other standards documents for cdma2000.

Table 1

In general, F-PDCH, F-PDCCH, R-ACKCH and R-CQICH are used for data transmission on the forward link. R-PDCH, R-REQCH, R-PICH, F-ACKCH and F-GCH are used for data transmission on the reverse link. In general, each channel may convey control information, data, pilot, other transmissions, or any combination thereof.

FIG. 2 shows exemplary data transmission on the forward link in cdma2000. The base station has a number of data packets to send to the terminal. The base station processes each data packet to generate an encoded packet, and further divides the encoded packet into a plurality of sub-packets. Each subpacket contains enough information to enable the terminal to decode and recover the packet under good channel conditions.

The base station transmits the first subpacket A1 of packet A on the F-PDCH in two time slots starting at time _T1 . In cdma2000, a slot has a duration of 1.25 milliseconds (ms). The base station also sends a 2-slot message on the F-PDCCH indicating that the transmission on the F-PDCH is intended for the terminal. The terminal receives and decodes subpacket A1, determines that packet A was decoded incorrectly, and sends a negative acknowledgment (NAK) on the R-ACKCH at time _T2 . In this example, the ACK delay is 1 slot. The base station transmits the first subpacket B1 of packet B on the F-PDCH in four time slots starting at time _T3 . The base station also sends a 4-slot message on the F-PDCCH indicating that the transmission on the F-PDCH is intended for the terminal. The terminal receives and decodes subpacket B1, determines that packet B was decoded correctly, and sends an acknowledgment (ACK) on the R-ACKCH at time _T4 . The base station transmits the second subpacket A2 of packet A on the F-PDCH in one slot starting at time _T5 . The terminal receives subpacket A2, decodes subpackets A1 and A2, determines that packet A was decoded incorrectly, and sends a NAK on the R-ACKCH at time _T6 .

The terminal also periodically measures the channel quality of base stations to which it may transmit data. The terminal identifies the best base station and sends a full channel quality indication (CQI) report and a difference (Diff) channel quality indication (CQI) report on the R-CQICH, as described below. The CQI report is used to select the most suitable base station to transmit data to the terminal and the suitable data rate for data transmission.

In cdma2000, the base station uses a pseudorandom number (PN) sequence to spectrally spread data at a rate of 1.2288 megachips per second (Mcps). The base station modulates the carrier signal with the spread data, and generates a radio frequency (RF) modulated signal, which has a bandwidth of 1.2288 MHZ. The base station then transmits an RF modulated signal on the forward link at a specific center frequency. Since the data is modulated on a single carrier, it is called single carrier CDMA. The capacity of the forward link is determined by the number of data bits that can be reliably transmitted in the 1.2288 MHz RF modulated signal. On the reverse link, the terminal also uses the PN sequence to spread the data at 1.2288 Mcps, and sends the spread data at a specific carrier frequency. The capacity of the reverse link is determined by the number of data bits that can be reliably transmitted on the data channel assigned to the terminal.

In one approach, multiple carriers are used on a link to achieve significant capacity improvements on that link. In one embodiment, a chip rate of 1.2288 Mcps is used for each of the multiple carriers, which is the same chip rate used for single carrier CDMA. This enables hardware designed for single-carrier CDMA to also support multi-carrier CDMA.

FIG. 3 shows a view of one embodiment of a multi-carrier structure 300 . In this embodiment, there are K carriers available on the forward link and M carriers available on the reverse link, where K>1 and M≧1. A forward link (FL) carrier is a carrier on the forward link and a reverse link (RL) carrier is a carrier on the reverse link. A carrier wave may also be called an RF channel, a CDMA channel, and so on. Set K FL carriers and M RL carriers into G groups, where G≥1. In general, any number of carrier groups can be formed, and each group can include any number of FL carriers and any number of RL carriers.

In the embodiment shown in FIG. 3 , each carrier group includes at least one FL carrier and one RL carrier, such that G=M and K≧M. As shown in Figure 3, carrier group 1 includes FL carriers 1 to N ₁ and RL carrier 1, carrier group 2 includes FL carriers N ₁ +1 to N ₁ +N ₂ and RL carrier 2, and so on, carrier group M includes FL Carrier KN _M +1 to K and RL Carrier M. In general, N ₁ to N _M may be the same or different. In one embodiment, N _m ≤ 4, m = 1, . . . , M, up to four FL carriers in each carrier group are associated with a single RL carrier.

The multi-carrier structure 300 supports a variety of system configurations. Configurations with multiple FL carriers and multiple RL carriers can be used for high-rate data transmission on the forward and reverse links. Configurations with multiple FL carriers and a single RL carrier can be used for high-rate data transmission on the forward link. A configuration with a single FL carrier and multiple RL carriers can be used for high rate data transmission on the reverse link. Selection of an appropriate configuration for a terminal may be based on various factors, such as available system resources, data requirements, channel conditions, and the like.

In one embodiment, the FL and RL carriers have different importance. For each group, one (e.g., the first) FL carrier in the group is designated as the group FL primary carrier (groupFL primary), and each remaining FL carrier in the group (if any) is designated as the group FL Auxiliary carrier (group FL auxiliary). One (eg, the first) FL carrier among the K FL carriers is designated as the primary FL carrier. Similarly, one (eg, the first) RL carrier among the M RL carriers is designated as the primary RL carrier.

A terminal may be assigned any number of FL carriers, where one FL carrier is designated as the primary FL carrier for that terminal. A terminal may also be assigned any number of RL carriers, where one RL carrier is designated as the primary RL carrier for that terminal. Different terminals may be assigned different sets of FL and RL carriers. Furthermore, a given terminal may be assigned different sets of FL and RL carriers over time based on those factors described above.

In one embodiment, the terminal uses the primary FL and RL carriers for the following functions:

Initiate a call on the primary RL carrier,

· On the primary FL carrier, during call setup to receive signaling,

Perform a Layer 3 signaling handover procedure on the primary FL carrier, and

• Select serving base station for FL transmission based on primary FL carrier.

In one embodiment, the group FL primary carrier in each carrier group controls the RL carriers in that group. Group FL primary carrier can be used for the following functions:

Send power control for R-PICH,

Send rate control for R-PDCH,

· Send an acknowledgment (on F-ACKCH) for the reverse link transmission,

· (on the F-PDCCH) send a MAC control message to the terminal, and

• (on F-GCH) Send a Forward Grant message to the terminal.

The data and control channels in cdma2000 revision D are designed for data transmission on a single carrier. Certain control channels may be modified to support data transmission on multiple carriers. This modification can make: (1) the modified control channel is backward compatible with the control channel in cdma2000 revision D; and (2) new changes can be easily implemented in software and/or firmware, for example, which can reduce the need for Effects on hardware design.

The base station may transmit data to the terminal on the forward link on any number of FL carriers in any number of carrier groups. In one embodiment, the RL carriers in each group transmit R-ACKCH and R-CQICH supporting all FL carriers in the group. In this embodiment, the R-ACKCH conveys acknowledgment of packets received on the F-PDCH for all FL carriers in the group. R-CQICH provides CQI feedback for all FL carriers in the group.

1. R-ACKCH

In another aspect, a new R-ACKCH structure that can support data transmission on multiple FL carriers is described. A terminal can monitor multiple FL carriers in a given group while transmitting on a single RL carrier, as shown in Figure 3. The terminal may receive multiple packets on multiple F-PDCHs sent on the multiple FL carriers. The terminal may acknowledge the multiple packets via a single R-ACKCH sent on a single RL carrier. R-ACKCH may be designed to have a function of transmitting acknowledgment for one or more packets according to the number of received FL carriers.

Figure 4A shows a block diagram of the R-ACKCH structure 410 used in cdma2000 Revision D. One R-ACKCH bit is generated every 1.25ms frame (which is one slot). The R-ACKCH bit may be: (1) if the packet is decoded correctly, the R-ACKCH bit is ACK; (2) if the packet is decoded incorrectly, the R-ACKCH bit is NAK; or (3) If there is no packet to acknowledge, the R-ACKCH bit is a null bit. The R-ACKCH bits are repeated 24 times by the symbol repetition unit 412 to generate 24 identical modulation symbols, which are further processed and sent on the R-ACKCH.

Figure 4B shows a block diagram of an embodiment of a new R-ACKCH structure 420 that can support up to four R-ACKCHs for up to four FL carriers. The four R-ACKCHs may also be considered four subchannels of a single R-ACKCH, and may be referred to as reverse acknowledgment subchannels (R-ACKSCH). In the following description, the acknowledgment channel for each FL carrier is called R-ACKCH instead of R-ACKSCH.

FIG. 4B shows the case where three R-ACKCHs are used for three FL carriers, which are also referred to as CDMA channels 0, 1 and 2. FIG. The R-ACKCH for each CDMA channel is implemented using a corresponding set of signal point mapping unit 422 , Walsh covering unit 424 and repetition unit 426 . CDMA channels 0, 1 and 2 are assigned 4-chip Walsh codes W ₀ ⁴ , W ₁ ⁴ and W ₂ ⁴ , respectively. Walsh codes are also known as Walsh functions or Walsh sequences, and are defined in TIA/EIA IS-2000.2.

For each CDMA channel, one R-ACKCH bit is generated in each 1.25ms frame (or time slot). For CDMA channel 0, the signal point mapping unit 422a maps the R-ACKCH bits for CDMA channel 0 to +1, -1 or 0 based on whether the R-ACKCH bits are ACK, NAK or null bits, respectively. The Walsh overlay unit 424a overlays the mapped values using the 4-chip Walsh code W ₀ ⁴ assigned to CDMA channel 0. Walsh covering is achieved by the following steps: (1) repeating the mapped value four times; and (2) multiplying the above four identical values by the four chips of the Walsh code W ₀ ⁴ to generate sequence of symbols. Repeat unit 426a repeats the 4-symbol sequence six times, thereby generating a sequence of 24 symbols for CDMA channel 0. The processing for CDMA channels 1 and 2 is similar to the processing for CDMA channel 0.

In each time slot, adder 428 adds the three 24-symbol sequences from repetition units 426a, 426b, and 426c for CDMA channels 0, 1, and 2, respectively, and provides the 24-symbol sequences corresponding to that slot. modulation symbol. These modulation symbols are further processed and transmitted. The base station can recover the R-ACKCH bits for each CDMA channel by performing reverse decovering with the Walsh code assigned to that CDMA channel.

FIG. 4C shows a block diagram of an embodiment of a new R-ACKCH structure 430 that can support, for example, up to eight R-ACKCHs for up to eight FL carriers. FIG. 4C shows a case where seven R-ACKCHs are used for seven FL carriers, which are also referred to as CDMA channels 0 to 6 . The R-ACKCH for each CDMA channel is implemented using a set of signal point mapping unit 432 , Walsh covering unit 434 and repetition unit 436 . CDMA channels 0 to 6 are assigned 8-chip Walsh codes W ₀ ⁸ to W ₆ ⁸ , respectively, which are defined in TIA/EIA IS-2000.2.

For each CDMA channel, the signal point mapping unit 432 maps the R-ACKCH bits for that CDMA channel to +1, -1 or 0. A Walsh covering unit 434 covers the mapped values with the 8-chip Walsh code assigned to the CDMA channel and provides a sequence containing eight symbols. Repeat unit 436 repeats the 8-symbol sequence three times to generate a sequence of 24 symbols for the CDMA channel. In each slot, adder 438 sums seven 24-symbol sequences from repetition units 436a through 436g for CDMA channels 0 through 6, respectively, and provides the 24 modulation symbols corresponding to that slot. These modulation symbols are further processed and transmitted.

4B and 4C illustrate exemplary R-ACKCH structures 420 and 430 that support multiple R-ACKCHs and are backward compatible with the current R-ACKCH structure 410 shown in FIG. 4A. If a CDMA channel is being received, the R-ACKCH bits for that CDMA channel are processed using Walsh code W ₀ ⁴ or W ₀ ⁸ , and the R-ACKCH bits for all other CDMA channels are set for empty bits. Thus, the output of adder 428 or 438 will be the same as the output of repeat unit 412 in FIG. 4A. Additional CDMA channels may be supported by sending R-ACKCH bits for the additional CDMA channels with other Walsh codes. Depending on the length of the Walsh code, the repetition factor is reduced from 24 to 6 or 3.

The R-ACKCH structure shown in FIG. 4B and FIG. 4C can recover the R-ACKCH bits using hardware designed for the R-ACKCH structure shown in FIG. 4A. The hardware can generate 24 received symbols for R-ACKCH in each slot. Decovering the 24 received symbols with Walsh codes can be performed in software and/or firmware, which can reduce the impact on base station upgrades to support multi-carrier operation.

Other structures may also be used to implement multiple R-ACKCHs, which are within the scope of the present invention. For example, multiple R-ACKCHs may be time multiplexed and sent at different intervals in a given slot.

2. R-CQICH

In another aspect, a new R-CQICH structure is described that can support CQI feedback for multiple FL carriers. A terminal can monitor multiple FL carriers in a given group while transmitting on a single RL carrier, as shown in Figure 3. The multiple FL carriers may observe different channel conditions (eg, different fading characteristics) and may obtain different received signal qualities at the terminal. It is hoped that the terminal can provide CQI feedback for as many allocated FL carriers as possible, so that the system can select an appropriate FL carrier for transmitting data and a suitable rate for each selected FL carrier. If the system configuration includes a single RL carrier, the terminal may send CQI feedback for all FL carriers via a single RL carrier on a single R-CQICH. The R-CQICH can be designed with the capability to transmit CQI feedback for one or more FL carriers.

In cdma2000 Revision D, the R-CQICH can operate in one of two modes in each 1.25 ms frame (or slot), full or differential. In full mode, a full CQI report including 4-bit values is sent on the R-CQICH. The 4-bit CQI value conveys the received signal quality of a CDMA channel. In difference mode, a difference CQI report including a 1-bit value is sent on the R-CQICH. The 1-bit CQI value conveys the difference in received signal quality between the current and previous time slot for a CDMA channel. The full CQI and differential CQI reports may be generated as described in TIA/EIA IS-2000.2.

Figure 5A shows a block diagram of the R-CQICH structure 510 used in cdma2000 Revision D. For CDMA channels, a 4-bit or 1-bit CQI value can be generated in each 1.25 ms frame (or slot) depending on whether full or differential mode is selected. The 4-bit CQI value is also called a CQI value symbol. A 1-bit CQI value is also called a difference CQI symbol. The block encoder 512 encodes the 4-bit CQI values using a (12,4) block code to generate a codeword with 12 symbols. A symbol repetition unit 514 repeats the 1-bit CQI value 12 times to generate 12 symbols. A switch 516 selects the output of the block encoder 512 for the full mode, or the repetition unit 514 for the differential mode.

The CQI report may be sent to a particular base station by overlaying the report with the Walsh code assigned to that base station. Walsh covering unit 518 receives the 3-bit Walsh codes for the base stations selected to serve the terminal and generates a corresponding 8-chip Walsh sequence. Unit 518 also repeats the 8-chip Walsh sequence 12 times and provides 96 Walsh chips in each slot. A modulo-2 adder 520 adds the symbols from switch 516 to the output of Walsh cover unit 518 to provide 96 modulation symbols in each slot. Walsh covering unit 518 and summer 520 efficiently cover each symbol from switch 516 with the 3-bit Walsh code for the selected base station. The channel point mapping unit 522 maps each modulation symbol to a +1 or -1 value. A Walsh covering unit 524 covers each mapped value from unit 522 with a Walsh code W ₁₂ ¹⁶ and provides output symbols that are further processed and sent on the R-CQICH.

The new R-CQICH structure can support full mode or differential mode for one or more FL carriers. In one embodiment, complete CQI reports for different FL carriers in a group are sent in different time slots in a TDM manner. In one embodiment, for a given slot, the differential CQI reports for all FL carriers in a group will be jointly encoded and sent together in that slot. Joint coding of differential CQI reports is more efficient than separate coding of a single differential CQI report. The repetition in block 514 may be replaced by more efficient encoding.

Figure 5B shows a block diagram of an embodiment of a new R-CQICH structure 530 that can provide CQI feedback for multiple CDMA channels. In this embodiment, block encoder 532 encodes 4-bit CQI values for one CDMA channel with a (12,4) block code to generate a codeword with 12 symbols. A block encoder 534 jointly encodes the N 1-bit CQI values for the N CDMA channels with a (12,N) block code to generate a codeword having 12 symbols. The block coding rate (R) is equal to the number of input bits/number of output bits, or R=4/12 for a (12,4) block code and R=N/12 for a (12,N) block code. Different code rates generate different amounts of redundancy and require different received signal qualities for reliable reception. Thus, depending on the number of CDMA channels N, different amounts of transmit power are used for the codewords from block encoder 534.

Switch 536 selects the output of block encoder 532 for full mode or the output of block encoder 534 for differential mode. Walsh cover unit 538, adder 540, signal point mapping unit 542, and Walsh cover unit 544 apply the symbols from switch 536 to to process. Walsh cover unit 544 provides output symbols that are further processed and sent on the R-CQICH.

The block encoding of encoder 534 can be represented by the following matrix:

y = u · G equation (1)

where u =[u ₀ u ₁ …u _k-1 ] is a 1×k row vector corresponding to a sequence of 1-bit CQI values, u ₀ is the first input bit in vector u ,

y = [y ₀ y ₁ ... y _n-1 ] is a 1×n row vector corresponding to the encoder output codeword, y ₀ is the first output bit in vector y, and

G is the k×n generator matrix for block encoding.

A block code is usually specified in its generator matrix. Different block codes can be defined for different values of N from 2 to 7 to support up to 7 CDMA channels. A block code corresponding to each value of N can be chosen to achieve good performance, measurable by the minimum distance between codewords. Table 2 lists exemplary block codes corresponding to N=2 to 7. The block codes in Table 2 have the largest possible minimum distance between codewords of a linear block code.

Table 2

The block encoding corresponding to N=1 may correspond to the 12*bit repetition performed by unit 514 in FIG. 5A. In the embodiment shown in Table 2, the (12,2) block code consists of a (3,2) block code followed by 4*sequence repetitions. The generator matrix for the (12,4) block code in encoder 534 is the same as the generator matrix for the (12,4) block code in encoders 512 and 532 . (12, 2), (12, 3), (12, 4), (12, 5), (12, 6) and (12, 7) block codes in Table 2 have 8, 6, 6, 4 , 4 and 4 minimum distances. For block codes for differential CQI reporting, other generator matrices can also be defined and used.

FIG. 5B shows an exemplary R-CQICH structure 530 that supports CQI feedback for multiple CDMA channels and is backward compatible with the current R-CQICH structure 510 shown in FIG. 5A. If only one CDMA channel is being received, the full CQI report for that CDMA channel can be processed with a (12,4) block code, the differential CQI report can be processed with 12×bit repetition, and the Walsh cover unit 544 The output of will be the same as the output of Walsh covering unit 524 in FIG. 5A. Additional CDMA channels may be supported by (1) sending full CQI reports for CDMA channels in different slots and (2) jointly sending differential CQI reports for CDMA channels in the same slot.

The R-CQICH structure shown in FIG. 5B can recover full and differential CQI reports for multiple CDMA channels by making minor changes to the R-CQICH structure shown in FIG. 5A. The hardware for the physical layer can block decode the complete CQI report. Demultiplexing of complete CQI reports for different CDMA channels can be performed at the Medium Access Control (MAC) layer. Block decoding of differential CQI reports may be performed at the physical or MAC layer.

Other structures could also be used to implement R-CQICH for multiple CDMA channels and would be within the scope of the present invention. For example, complete CQI reports for multiple CDMA channels may be block coded and sent in the same time slot. As another example, differential CQI reports for a subset of multiple CDMA channels may be sent in one slot.

A terminal can be assigned multiple FL and RL carrier groups, as shown in FIG. 3 . For each carrier group, the R-CQICH sent on the RL carriers in the group may convey the CQI reports for the FL carriers in the group, as described in Figure 5B. The CQI report can be sent in various ways.

6A-6E illustrate some exemplary transmissions on the R-CQICH. In these figures, full CQI reports are represented by taller boxes and differential CQI reports are represented by shorter boxes. The height of the box roughly indicates the amount of transmit power used to send the CQI report. The value within each box indicates the FL carrier reported by the CQI report sent in that box.

Figure 6A shows the transmission of full CQI and differential CQI reports for two FL carriers 1 and 2 on the R-CQICH. In this example, a full CQI report for FL carrier 1 is sent in one slot, then a differential CQI report for FL carriers 1 and 2 is sent in some number of slots, then a CQI report is sent in one slot For a full CQI report for FL carrier 2, then a differential CQI report for FL carriers 1 and 2 is sent in some number of slots, then a full CQI report for carrier 1 is sent in one slot, and so on . In general, the complete CQI report for each FL carrier can be sent at any rate, and the same or different reporting rates can be used for multiple FL carriers. In one embodiment, a full CQI report is sent in one (eg, first) slot of each 20 ms frame and a differential CQI report is sent in the remaining 15 slots of the frame. The complete CQI reports for FL carriers 1 and 2 may be alternated as shown in Figure 6A, or may be multiplexed in other ways.

Figure 6B shows the transmission of a complete CQI report for two FL carriers 1 and 2 on the R-CQICH. In this example, a full CQI report for FL carrier 1 is sent in one slot, then a full CQI report for FL carrier 2 is sent in the next slot, then a full CQI report for FL carrier 1 is sent in the next slot Full CQI report, and so on.

Figure 6C shows the transmission of the full CQI and differential CQI reports for the three FL carriers 1, 2 and 3 on the R-CQICH with a repetition factor of 2 or REP=2. In this example, a full CQI report for FL carrier 1 is sent in the first two slots of a 20 ms frame, then a differential CQI report for FL carriers 1, 2 and 3 is sent in each remaining slot of the frame , then send a full CQI report for FL carrier 2 in the first two slots of the next 20ms frame, then send a differential CQI report for FL carriers 1, 2 and 3 in each remaining slot of the frame, Then, send a full CQI report for FL carrier 3 in the first two slots of the next 20ms frame, then send a differential CQI report for FL carriers 1, 2, and 3 in each remaining slot of the frame, and then , the complete CQI report for FL carrier 1 is sent in the first two slots of the next 20ms frame, and so on. Similar to the full CQI report, the differential CQI report may be sent in two consecutive slots, or alternatively, may be sent in a single slot.

FIG. 6D shows the transmission of a complete CQI report for three FL carriers 1 , 2 and 3 on the R-CQICH with a repetition factor of 2. FIG. In this example, the full CQI report for FL carrier 1 is sent in two slots, then the full CQI report for FL carrier 2 is sent in the next two slots, then in the next two slots For the full CQI report for FL carrier 3, then the full CQI report for FL carrier 1 is sent in the next two slots, and so on.

Figure 6E shows the transmission of a complete CQI report for three FL carriers 1, 2 and 3 on the R-CQICH with a repetition factor of 2 and with two switching slots. In this example, the complete CQI reports for FL carriers 1, 2 and 3 are sent in the same manner as described above for FIG. 6D. However, the last four slots of the 20ms frame are used to send the switch slot pattern (denoted as "s" in Figure 6E), which is the message to switch to the new serving base station.

As shown in FIGS. 6A-6E , time division multiplexing of complete CQI reports for all FL carriers results in a decrease in the reporting rate of complete CQI reports for a given FL carrier as the number of FL carriers in the group increases. For example, if a group includes 7 FL carriers, then for each FL carrier, a complete CQI report can be sent at a rate of once every 7*20ms=140ms. The joint coding of differential CQI reports for all FL carriers results in a reporting rate of differential CQI reports that is independent of, and not affected by, the number of FL carriers in the group. When switching to a new cell, the switching slot map "punctures" (or replaces) the full CQI report. This puncturing may not affect all FL carriers equally. In the example shown in FIG. 6E, the switching slot map affects FL carriers 1 and 2, but not FL carrier 3.

In one embodiment, the terminal selects a single base station for data transmission on the forward link. The base station may be selected based on the received signal quality measured at the terminal for the primary FL carrier, all of the assigned FL carriers, or a subset of the assigned FL carriers. The R-CQICH for all RL carriers uses Walsh coverage for the selected base station, thus pointing to the same cell. The choice of a single base station avoids out-of-order transmissions on the forward link and potential negative impact on the Radio Link Protocol (RLP). In the forward direction, RLP frames are typically pre-packed at the base station controller (BSC) and then forwarded to the base station for transmission to the terminal. Therefore, out-of-order transmission of RLP frames can be avoided by transmitting from a single base station.

In another embodiment, the terminal may select multiple base stations for data transmission on the forward link. As mentioned above, since the fading characteristics may be different for different FL carriers, this embodiment enables the terminal to select a suitable base station for each FL carrier or group of FL carriers, which can improve the overall throughput.

3. R-PICH

It is desirable to reduce the reverse link overhead for data transmission on the forward link. This can be achieved by assigning a terminal a single carrier group comprising multiple FL carriers and a single RL carrier. Data can be sent on multiple FL carriers, and acknowledgments and CQI feedback can be efficiently sent on a single RL carrier.

In certain cases, multiple RL carriers may be used. For example, the base station may not support the above-mentioned new R-ACKCH and R-CQICH structures. In this case, each FL carrier may be associated with one RL carrier that supports R-ACKCH and R-CQICH for that FL carrier.

In cdma2000 Revision D, terminals send pilots on the R-PICH to help base stations detect reverse link transmissions. If a single RL carrier is allocated, the pilot overhead is shared among all FL carriers associated with that RL carrier. However, if multiple RL carriers are allocated, and if R-PICH is sent on each RL carrier to support R-ACKCH and R-CQICH, for low data rates on the reverse link, the pilot overhead may be very remarkable. Pilot overhead reduction can be achieved by using a control-hold pattern.

Figure 7 shows the transmission of full and gated pilots on the R-PICH. Full pilots are pilot transmissions in every slot with a pilot gating rate of 1. The Control-Hold mode defined in cdma2000 Revision D (or simply "Rev D Control-Hold Mode") supports pilot gating rates of 1/2 and 1/4. As shown in Figure 7, gated pilots are pilot transmissions in certain slots, or more specifically, pilot transmissions every other slot for a pilot gating rate of 1/2, and For a pilot gating rate of 1/4, pilot transmission occurs every fourth time slot.

In cdma2000 Revision D, typically, the base station puts the terminal in control-hold mode by sending a layer 3 message after the control-hold timer expires. For example, if the base station has not received any data from the terminal and has not sent any data to the terminal for a certain period of time, the base station can send a Layer 3 message to the terminal to put it in control-hold mode. If new data arrives at the base station or the terminal, a transition from the control-hold mode is triggered. If new data arrives at the terminal, the terminal spontaneously transitions out of control-hold mode and starts sending full pilots and data on the reverse link. The base station detects that the terminal has transitioned out of control-hold mode and decodes the data sent with the full pilot. If new data arrives at the base station, the base station first wakes up the terminal by sending a MAC message on the F-PDCCH. In control-hold mode, the terminal does not process F-PDCH in order to save power.

Many applications have the characteristics of asymmetric data services, and these applications may require multiple F-PDCHs on multiple FL carriers. Therefore, multiple reverse pilots may need to be transmitted on multiple RL carriers to support multiple F-PDCHs. In addition to the reverse pilot, the services on the auxiliary RL carrier may only include the CQI report on the R-CQICH and the acknowledgment on the R-ACKCH. In this case, the use of control-hold mode can significantly reduce the reverse link overhead on the secondary RL carrier.

However, the Revision D control-hold mode is not directly applied to the secondary RL carrier for the following reasons. First, in Revision D control-hold mode, the terminal does not decode the F-PDCH. Second, the terminal needs to transition out of Revision D Control-Hold mode before transmitting on R-ACKCH, and a Layer 3 message from the base station is required to set the terminal back to Control-Hold mode. It is undesirable that a terminal has to send a Layer 3 message every time it transmits on R-ACKCH. Furthermore, since the base station sends the Layer 3 message after the control-hold timer expires (typically on the order of a few hundred milliseconds), a full pilot is sent on the reverse link during this time.

In another aspect, an "auxiliary" control-holding mode is defined for use on the auxiliary RL carrier. In one embodiment, the auxiliary control-hold mode differs from the Rev. D control-hold mode in that:

· The terminal may process F-PDCH during auxiliary control-holding mode,

A terminal can send an acknowledgment on R-ACKCH without transitioning out of secondary control-hold mode,

· If the F-PDCH is successfully decoded, the terminal can spontaneously send the full pilot and acknowledgment on the R-ACKCH, and

• The terminal may continue with pilot gating after completing the R-ACKCH transmission. Different and/or other characteristics may also be used to define the secondary control-hold mode.

In order to reduce pilot overhead on the reverse link, Revision D control-hold mode can be used on the primary RL carrier, and secondary control-hold mode can be used on each secondary RL carrier. Two versions of the control-hold mode can support efficient operation of multiple RL carriers in multi-carrier operation.

In one embodiment, control-holding patterns can be defined independently for each RL carrier. The following situations may occur:

• The primary RL carrier is in active mode, any number of secondary RL carriers may be in control-hold mode. The terminal can process the F-PDCH of the secondary RL carrier and can transmit on the R-ACKCH without leaving control-hold mode.

• All RL carriers are in control-hold mode. The terminal does not process the F-PDCH and does not transmit on the R-ACKCH without leaving control-hold mode. This is a power saving mode.

4. R-REQCH

The terminal can send various types of information to the base station on the R-REQCH. The trigger for sending the R-REQCH message in cdma2000 Revision D can also be used as the trigger for sending the R-REQCH message in multi-carrier operation. In one embodiment, the terminal sends an R-REQCH message on the primary RL carrier to convey service related information to the base station. One buffer may be maintained per service for data transmission on all RL carriers. Service related information may include buffer size and watermark crossing. In one embodiment, the terminal sends R-REQCH messages on the primary and secondary RL carriers to convey the power headroom for these RL carriers. The power report trigger for each RL carrier may be used to send an R-REQCH message to convey the power headroom range for that RL carrier.

5. Scheduling

Terminals may be scheduled for data transmission on the forward and reverse links in a number of ways. Centralized scheduling can be performed for multiple carriers, or distributed scheduling can be performed for each carrier. In one embodiment, a centralized scheduler is used to schedule terminals for data transmission on multiple carriers. The centralized scheduler can support flexible scheduling algorithms that can use CQI information on all carriers to improve throughput and/or provide desired Quality of Service (QoS). In another embodiment, a distributed scheduler is used for each carrier and terminals are scheduled on that carrier. Distributed schedulers for different carriers can operate independently of each other, and existing scheduling algorithms of cdma2000 Revision D can be reused.

A terminal may be assigned multiple carriers, which may be supported by a single channel card or multiple channel cards at the base station. If multiple FL carriers are handled by different channel cards, there will be a channel card communication delay, which may be on the order of milliseconds. Although this delay is small, it is typically greater than 1.25ms, which is the time to decode the R-ACKCH, the preferred time to decode the R-CQICH, and the time to schedule new transmissions on the F-PDCH.

The centralized scheduler may incur additional scheduling delays if multiple channel cards are used for different FL carriers. This additional delay consists of two parts. The first part is the R-CQICH delay for delivering CQI feedback from the channel card handling reverse link decoding to the centralized scheduler. The second part is the delay for the selected encoder packets to reach the channel card handling the F-PDCH transmission. Additional delay may affect system throughput, however, its effect should be limited to a relatively narrow range of speeds and channel models.

For example, if reverse link decoding and forward link transmission are handled by a single channel card, the distributed scheduler may not incur the additional latency described above for the centralized scheduler. This approach is applicable if there is no auxiliary carrier in the carrier group. However, if a distributed scheduler is implemented on each channel card, it is possible to maintain a separate buffer for each channel card so that data can be co-located with the scheduler. This card buffer may be small and a larger buffer may be located at the base station. The distributed scheduler should have enough data to schedule the business. The latency to get additional data from larger buffers can be on the order of milliseconds. The card buffer size should take into account the highest possible air data rate to avoid buffer underflow. Although the buffer at the channel card may be relatively small, the reception of RLP frames at the terminal is likely to be out of order. Therefore, it is possible to use longer detection windows for RLP frames. Since the traditional early NAK technology does not take into account that the traffic flow may be out of order in the first transmission, it is not practical. A longer delay detection window in RLP may have a larger impact on TCP. Multiple RLP instances may be used, eg one per F-PDCH, but this may result in out-of-order arrival of TCP segments.

RLP frames are usually pre-compressed at the BSC and MUX overhead is added. In cdma2000, each RLP frame (including MUX overhead) contains 384 bits, which are identified by a 12-bit sequence number. The cdma2000 RLP header allocates 12 bits for the RLP frame sequence number, which is used to reassemble the RLP frame at the terminal. Given the small size of the RLP frame, this sequence space may not be suitable for high rates such as those available in multi-carrier configurations. In order to support high data rates with existing RLP, RLP frames can be pre-segmented so that the additional 12-bit sequence space for segmented RLP frames can be reused. Sequence space is not an issue on the reverse link since there is no need to pre-compress RLP frames.

The call setup procedure for multi-carrier operation may be implemented as follows. The terminal obtains system information from the forward synchronization channel (F-SYNCH), and obtains overhead messages from the forward paging channel (F-PCH) or forward broadcast control channel (F-BCCH) transmitted on the main FL carrier. The terminal can then initiate a call on the primary RL carrier. The base station may assign a traffic channel to the terminal via an Extended Channel Assignment Message (ECAM) sent on the primary FL carrier. The terminal obtains the traffic channel and transfers to the mobile station control traffic channel state, which is one of the mobile station operating states in cdma2000. In one embodiment, the operational status is only defined for the primary carrier. The base station can then allocate multiple FL and RL carriers via eg Universal Handover Direction Message (UHDM). When initializing traffic channels on a new carrier, the base station may start sending commands on the forward common power control channel (F-CPCCH) after sending the UHDM. The terminal may start sending R-PICH upon receiving UHDM. The terminal can send a handover completion message (HCM) to the base station on the main RL carrier to indicate the acquisition of the F-CPCCH, where the HCM is a cdma2000 layer-3 protocol message.

6. Processes and Systems

FIG. 8 illustrates an embodiment of a process 800 performed by a terminal for multi-carrier operation. The terminal receives an assignment of a plurality of forward link (FL) carriers and at least one reverse link (RL) carrier (block 812). The terminal may receive data transmissions on one or more of the plurality of FL carriers (block 814). The terminal may demodulate and decode received data transmissions for each FL carrier separately (block 816). The terminal may also send data on at least one RL carrier (block 818). Terminals may be scheduled for data transmission on the forward and/or reverse links based on various factors, such as availability of system resources, amount of data to be transmitted, channel conditions, and so on.

The terminal may send designated RL signaling on a primary RL carrier, where the primary RL carrier may be designated from at least one RL carrier (block 820). The terminal may receive designated FL signaling on a primary FL carrier, where the primary FL carrier may be designated from a plurality of FL carriers (block 822). For example, a terminal may initiate a call on the primary RL carrier and may receive signaling for call setup on the primary FL carrier. The terminal may select a base station for data transmission on the forward link based on the received signal quality of the primary FL carrier.

A plurality of FL carriers and at least one RL carrier may be arranged in at least one group. Each group may include at least one FL carrier and one RL carrier, as shown in FIG. 3 . The terminal may receive packets on the FL carriers in each group and may send acknowledgments for received packets via the RL carriers in the group. The terminal may also send CQI reports for the FL carriers in each group via the RL carriers in that group. One FL carrier in each group can be designated as a group primary FL carrier. The terminal may receive signaling for the RL carriers in each group via the group primary FL carrier.

FIG. 9 illustrates an embodiment of a process 900 for sending an acknowledgment. The terminal receives packets on multiple data channels (eg, F-PDCH) transmitted via multiple forward link (FL) carriers (block 912). The terminal determines an acknowledgment for the packet received on the data channel (block 914). The terminal channelizes acknowledgments for each data channel with an orthogonal code (eg, a Walsh code) assigned to the data channel to generate a sequence of symbols for the data channel (block 916). The terminal repeats the sequence of symbols for each data channel multiple times (block 918). The terminal may generate modulation symbols for an acknowledgment channel (eg, R-ACKCH) based on the repeated symbol sequences for multiple data channels (block 920).

The number of data channels is configurable. For example, due to cdma2000 Revision D backward compatibility, if an acknowledgment is only sent for one data channel, an orthogonal code of all zeros or all ones may be used. Orthogonal codes of a first length (eg, four chips) may be used if the number of data channels is less than a first value (eg, four). If the number of data channels is equal to or greater than the first value, an orthogonal code of a second length (eg, eight chips) may be used. The repetition factor may also depend on the number of data channels.

Figure 10 illustrates an embodiment of a process 1000 for sending a channel quality indication (CQI) report. The terminal obtains full CQI reports for multiple forward link (FL) carriers, each full CQI report indicating received signal quality for one FL carrier (block 1012). The terminal channelizes each complete CQI report with an orthogonal code (eg, Walsh code) for the selected base station (block 1014). The terminal sends complete CQI reports for multiple FL carriers on the CQI channel at different time intervals (or slots) (block 1016). The terminal may cycle through multiple FL carriers, selecting one FL carrier at a time, and sending a full CQI report for each selected FL carrier in the time interval designated for sending a full CQI report.

The terminal obtains differential CQI reports for multiple FL carriers for a specific time interval (block 1018). The terminal jointly encodes the differential CQI reports of multiple FL carriers to obtain a codeword (block 1020). The terminal may select a block code based on the number of FL carriers, and may jointly encode the differential CQI report with the selected block code. The terminal may channelize the codeword with the orthogonal code for the selected base station (block 1022). The terminal then transmits the codewords on the CQI channel in specified time intervals (block 1024).

11 illustrates an embodiment of a process 1100 for reducing pilot overhead, eg, in multi-carrier operation. The terminal operates in a control-hold mode that allows transmission of the gated pilot (block 1112). In control-hold mode, the terminal receives a data channel (eg, F-PDCH) sent on the forward link (block 1114). If no other transmissions are being sent on the reverse link, the terminal sends a gated pilot on the reverse link (block 1116). If there are transmissions being sent on the reverse link, the terminal sends a full pilot on the reverse link (block 1118). For example, a terminal may generate an acknowledgment for a packet received on the data channel, send the acknowledgment on the reverse link along with the full pilot, and continue to send the gated pilot on the reverse link after completing transmission of the acknowledgment . The terminal transitions out of control-hold mode in response to an exit event, which may be signaling to exit control-hold mode, receipt of a data transmission on the reverse link, etc. (block 1120).

8 to 11 illustrate processes performed by a terminal for multi-carrier operation. The base station performs the opposite process to support multi-carrier operation.

FIG. 12 shows a block diagram of an embodiment of a base station 110 and a terminal 120 . For the forward link, at base station 110, an encoder 1210 receives traffic data and signaling for the terminals. Encoder 1210 processes traffic data and signaling (e.g., encoding, interleaving, and symbol mapping) and generates forward link channels (e.g., F-PDCH, F-PDCCH, F-ACKCH, and F-GCH ) output data. A modulator 1212 processes (eg, channelizes, spreads, and scrambles) the output data for multiple forward link channels and generates output chips. A transmitter (TMTR) 1214 conditions (eg, converts to analog, amplifies, filters, and frequency upconverts) the output chips and generates a forward link signal that is sent via antenna 1216 .

At terminal 120, an antenna 1252 receives the forward link signal from base station 110 as well as signals from other base stations and provides the received signal to a receiver (RCVR) 1254. Receiver 1254 conditions (eg, filters, amplifies, downconverts, and digitizes) the received signal and provides data samples. A demodulator (Demod) 1256 processes (eg, descrambles, despreads, and dechannelizes) the data samples and provides symbol estimates. In one embodiment, receiver 1254 and/or demodulator 1256 performs filtering to pass all FL carriers of interest. A decoder 1258 processes (eg, demaps, deinterleaves, and decodes) the symbol estimates and provides decoded data corresponding to traffic data and signaling sent by base station 110 to terminal 120 . Demodulator 1256 and decoder 1258 may perform demodulation and decoding on each FL carrier independently.

On the reverse link, at terminal 120, encoder 1270 processes traffic data and signaling (e.g., acknowledgments and CQI reports) and generates multiple reverse link channels (e.g., R-PDCH, R-ACKCH, R-CQICH, R-PICH and R-REQCH) output data. A modulator 1272 further processes the output data and generates output chips. A transmitter 1274 conditions the output chips and generates a reverse link signal that is sent via antenna 1252 . At base station 110, the reverse link signal is received by antenna 1216, conditioned by receiver 1230, processed by demodulator 1232, and further processed by decoder 1234 to recover the data and signaling transmitted by terminal 120 .

Controllers/processors 1220 and 1260 direct the operation at base station 110 and terminal 120, respectively. Memories 1222 and 1262 store data and program codes for controllers/processors 1220 and 1260, respectively. A scheduler 1224 may assign FL and/or RL carriers to terminals and may schedule the terminals for data transmission on the forward and reverse links.

The multi-carrier transmission technique described herein has the following beneficial properties:

· Multicarrier forward link backwards compatible with Revision D forward link - no changes made to the Revision D physical layer

Multicarrier reverse link backward compatible with revision D reverse link - new backward compatible R-ACKCH and R-CQICH structures that do not affect hardware implementations, and

• Flexible configurable system—K FL carriers and M RL carriers, where K≦N×M and K≧M.

The transmission techniques described herein can provide several advantages. First, these techniques allow cdma2000 Revision D to support multiple carriers using only or almost exclusively software/firmware upgrades. Only relatively minor changes have been made to certain RL channels (eg, R-ACKCH and R-CQICH) to support multi-carrier operation. These changes can be implemented with a software/firmware upgrade at the base station so that existing hardware such as channel cards can be reused. Second, higher peak data rates can be supported on the forward and reverse links. Third, the use of multiple F-PDCHs on multiple FL carriers can improve diversity and thus QoS. The flexible carrier structure enables incremental increases in data rates as VLSI technology advances.

The headings included in this document are for reference and are helpful in locating specific sections. These headings are not intended to limit the scope of the concepts described below, which may apply to other sections throughout the specification.

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

Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination thereof. To clearly illustrate this interchangeability of hardware and software, several illustrative components, blocks, modules, circuits, and steps have been described above in terms of their functionality. Whether a function is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation determination should not be considered as a departure from the scope of the present invention.

A general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or designed to Implementing any combination of the functions described herein implements the various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein. A general-purpose processor may be a microprocessor, but in the alternative, 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 DSP and a microprocessor, multiple microprocessors, one or more microprocessors with a DSP core, or any other such configuration.

The steps of methods or algorithms described in conjunction with the embodiments disclosed herein may be directly implemented in hardware, software modules executed by a processor, or a combination of both. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may reside within the processor. Processors and storage media can reside within an ASIC. The ASIC may reside within the user terminal. Optionally, the processor and the storage medium can be used as discrete components in the user terminal.

The above description of the disclosed embodiments is provided 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 intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features described herein.

Claims (16)

1. A method of improving capacity for high data rate transmissions in wireless communications, comprising:

receiving an assignment of a plurality of Forward Link (FL) carriers and at least one Reverse Link (RL) carrier; and

receiving a data transmission on one or more of the plurality of FL carriers;

wherein the allocation defines a difference between the number of the FL carriers allocated and the number of the at least one RL carrier allocated, and wherein the difference is based on one of a transmission channel condition, a desired data transmission rate, and available transmission resources.

2. The method of claim 1, further comprising:

receiving designated FL signaling on a primary FL carrier of the plurality of FL carriers; and

designated RL signaling is sent on a primary RL carrier of the at least one RL carrier.

3. The method of claim 1, wherein the plurality of FL carriers and the at least one RL carrier are arranged in at least one group, each group including at least one FL carrier and one RL carrier, and wherein the method further comprises:

receiving a packet on the at least one FL carrier in each group; and

sending an acknowledgement for the received packet in each group via the RL carrier in that group.

4. The method of claim 3, further comprising:

transmitting a Channel Quality Indication (CQI) report for the at least one FL carrier in each group via the RL carrier in that group.

5. The method of claim 1, further comprising:

the data transmission received on each FL carrier is independently demodulated and decoded.

6. The method of claim 2, further comprising:

initiating a call on the primary RL carrier; and

signaling for call setup is received on the primary FL carrier.

7. The method of claim 2, further comprising:

selecting a base station for data transmission on a forward link based on a received signal quality of the primary FL carrier.

8. The method of claim 3, wherein one FL carrier in each group is designated as a group primary FL carrier, and wherein the method further comprises:

receiving signaling for the RL carriers in each group via the group of primary FL carriers.

9. An apparatus for improving capacity for high data rate transmissions, comprising:

means for receiving an assignment of a plurality of Forward Link (FL) carriers and at least one Reverse Link (RL) carrier; and

means for receiving a data transmission on one or more of the plurality of FL carriers;

wherein the allocation defines a difference between the number of the FL carriers allocated and the number of the at least one RL carrier allocated, and wherein the difference is based on one of a transmission channel condition, a desired data transmission rate, and available transmission resources.

10. The apparatus of claim 9, further comprising:

means for receiving designated FL signaling on a primary FL carrier of the plurality of FL carriers; and

means for transmitting designated RL signaling on a primary RL carrier of the at least one RL carrier.

11. The apparatus of claim 9, wherein the plurality of FL carriers and the at least one RL carrier are arranged in at least one group, each group comprising at least one FL carrier and one RL carrier, and wherein the apparatus further comprises:

means for receiving a packet on the at least one FL carrier in each group; and

means for transmitting an acknowledgement for a received packet in each group via the RL carrier in that group.

12. The apparatus of claim 11, further comprising:

means for transmitting a Channel Quality Indication (CQI) report for the at least one FL carrier in each group via the RL carrier in the group.

13. The apparatus of claim 9, further comprising:

means for independently demodulating and decoding the data transmission received on each FL carrier.

14. The apparatus of claim 10, further comprising:

means for initiating a call on the primary RL carrier; and

means for receiving signaling for call setup on the primary FL carrier.

15. The apparatus of claim 10, further comprising:

means for selecting a base station for data transmission on a forward link based on a received signal quality of the primary FL carrier.

16. The apparatus of claim 11, wherein one FL carrier in each group is designated as a group primary FL carrier, and wherein the apparatus further comprises:

means for receiving signaling for the RL carriers in each group via the set of primary FL carriers.

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