CN101632323B - Method for allocating resources to uplink control channel - Google Patents

Abstract

A method for adaptively allocating resources of an uplink control channel according to a system situation is disclosed. If the Base Station (BS) recognizes a system situation, establishes control information for resource allocation, and transmits the control information to the Mobile Station (MS), the Mobile Station (MS) allocates resources for transmitting uplink control information using a specific block or a specific resource allocation method according to the corresponding control information. The system situation may vary according to the number of users included in the coverage of the BS or the use of multiple antennas. Actively reflect changes in the system situation so that uplink channel resources can be efficiently used.

Description

Method for allocating resources to uplink control channel

technical field

The present invention relates to a method for adaptively allocating resources of an uplink control channel according to system conditions.

Background technique

A 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) system includes one or more physical channels and logical channels mapped to the one or more physical channels. The logical channels are divided into control channels, common channels, dedicated control channels and traffic channels and so on. Specifically, one example of an uplink control channel may be a Channel Quality Information Channel (CQICH).

A conventional method for allocating resources to an uplink control channel is a pre-reserved method. The pre-reservation method estimates the amount of control information to be transmitted to the uplink, pre-reserves an appropriate amount of uplink resources, and allows multiple users to share the corresponding resources.

An advantage of this pre-reserved method is that it is not necessary to transmit downlink control information capable of transmitting commands associated with the resource allocation method to a mobile station (MS). However, it is difficult to properly handle some troublesome situations caused by insufficient or excessive pre-reserved resources.

In other words, the number of users included in the coverage of the base station (or Node B), or the amount of various control information fed back to the uplink can be changed to others according to the situation of the system. The above system situation may indicate the number of users of the uplink channel, specific information indicating whether to use the uplink control channel, the amount of data or control information transmitted via the uplink control channel, interference level, and specific information indicating whether to use multiple antennas , channel quality information transmission scheme and channel conditions, etc.

In this case, if the number of users of the uplink channel increases, or the amount of uplink channel control information increased by the mobile station (MS) based on the multi-antenna scheme is larger than the amount of resources reserved in advance, the prereserved method must transmit The uplink channel control information is several times so that it cannot achieve smooth communication between the transmitting end and the receiving end. In addition, if a few users are located in the coverage of the base station and the amount of control information to be transmitted to the uplink is low, the pre-reserved method has a disadvantage in that it unconditionally allocates unnecessary resources including unused All pre-reserved resources, resulting in wasted resources.

Contents of the invention

Accordingly, the present invention is directed to a method for allocating resources to an uplink control channel that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a method for adaptively allocating resources to an uplink control channel according to changes in the number of users included in the coverage of a base station and the amount of feedback information.

Additional advantages, objects and features of the present invention will be partially set forth in the following description, and some of them will become apparent to those of ordinary skill in the art or can be learned from the practice of the present invention when referring to the following content. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages, and in accordance with the object of the present invention, as embodied and broadly described herein, a resource allocation method for transmitting uplink control information in a mobile communication system, comprising: A mobile station (MS) receives control information established by a base station (BS) in view of a system situation; and allocates resources of an uplink control channel according to the received control information.

In another aspect of the present invention, there is provided a method for transmitting downlink control information to allocate resources of an uplink channel in a mobile communication system, comprising: generating, by a base station (BS) in view of system conditions, a method for allocating control information of resources of an uplink control channel; transmitting the control information to a mobile station (MS); and allocating resources of the uplink control channel according to the control information.

Preferably, the system conditions include the number of uplink/downlink users, the amount of transmitted data, the amount of control information, channel conditions, channel quality information transmission schemes, the amount of allocated resources, the amount of available resources, interference and control At least one of the allocation positions of the channel.

Preferably, the control information for allocating resources of the uplink control channel includes at least one of an amount of allocated resources required for smoothly transmitting the uplink control information and an appropriate resource allocation position.

Preferably, the resource allocation location includes at least one of information indicating a resource region in which the uplink control information is to be transmitted and information indicating a resource allocation scheme.

In this case, the resource allocation scheme can be divided into a partial transmission method and a repeated transmission method. If an area for transmitting control information is larger than a maximum area/capacity that can be allocated to a single symbol or a single subframe, the partial transmission method transmits corresponding control information separately over several symbols or subframes. This repeated transmission method may be used together with the partial transmission method, or may be used separately from the partial transmission method so that it controls uplink control information repeatedly transmitted over several subframes.

The extended block of this part of the transmission method may belong to the symbol or subframe to which the basic block belongs, and the symbol is the same as the subframe. In addition, the extended block may belong to the symbol or subframe to which the basic symbol belongs, and the symbol is different from the subframe.

Extended or repeated resource allocation for partial or repeated transmission methods is achieved by frequency hopping actions per subframe.

Preferably, the resources may be allocated to maintain single carrier characteristics between constituent information elements of the uplink control information.

Preferably, the resources may be allocated to maintain single carrier characteristics between uplink control information and uplink data.

The uplink control information may be CDM or TDM multiplexed with uplink user data so that the multiplexed uplink control information may be transmitted to a destination.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Beneficial effect

The present invention can adaptively allocate uplink resources to a target object according to changes in the number of users contained in the coverage of the base station and the amount of feedback information, so that it can use resources effectively, resulting in mobile stations (MS) and Increased communication throughput between base stations.

Description of drawings

The accompanying drawings, which are included to provide a further understanding of the invention, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.

In the attached picture:

1 is a schematic diagram illustrating a method for allocating resources to an uplink control channel according to the present invention;

2 is a schematic diagram illustrating an example of a resource allocation method from among the resource allocation methods of the present invention according to the present invention;

3 is a schematic diagram illustrating a method for multiplexing uplink control information from the resource allocation method of the present invention according to one embodiment of the present invention; and

FIG. 4 is a schematic diagram illustrating a method for multiplexing uplink control information from a resource allocation method of the present invention according to another embodiment of the present invention.

Detailed ways

Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

The techniques disclosed below will be used in various communication systems. Communication systems are deployed in a wide range of areas to provide various communication services (for example, voice or packet data) to users. The techniques described above can be applied to downlink or uplink. In this case, downlink means data communication from a base station (BS) to a mobile station (MS), and uplink means data communication from a mobile station (MS) to a base station (BS).

In general, a base station (BS) means a fixed station communicating with a mobile station (MS), and may also be called a Node B, BTS (Base Transceiver System), or an Access Point (AP), among others. A mobile station (MS) may be fixed at a specific location or may have mobility such that it may also be referred to as user equipment (UE), user terminal (UT), subscriber station (SS) or wireless device, among others.

FIG. 1 is a schematic diagram illustrating a method for allocating resources to an uplink control channel according to the present invention.

<Operation of base station (BS)>

A base station (BS) establishes control information required for allocating resources to an uplink control channel in view of system circumstances, and transmits the established control information to a mobile station (MS).

In FIG. 1 , an area A indicates a downlink resource allocation area capable of transmitting the above-mentioned control information to a mobile station (MS).

The system situation that must be recognized by the base station (BS) includes at least one of various information such as the number of uplink/downlink users, downlink transmission data volume, uplink control information volume, channel situation, usage In terms of the method of transmitting channel quality information, the amount of currently allocated resources, the amount of currently available resources, the degree of interference between users, and the allocation position of the control channel.

The control information transmitted to the downlink by the base station (BS) to achieve scheduling includes at least one of an allocated resource amount and an allocated position required for smoothly transmitting the uplink control information.

In this case, the allocation location contained in the above-mentioned control information includes at least one of a block (LB or SB) capable of transmitting the control information and a resource location method (also referred to as a resource allocation method). The block LB or SB to be transmitted and the resource location method will be described in detail below.

<Operation of mobile station (MS)>

A mobile station (MS) refers not only to the amount of uplink control information contained in the above control information but also to a resource allocation position contained in the above control information, and transmits resources of an uplink control channel.

In FIG. 1 , a region B represents a downlink resource allocation region capable of transmitting the above-mentioned control information to a mobile station (MS). In other words, the B area represents a specific area scheduled by control information received from a base station (BS). The B area is variable with the amount of control information, and the position and size of the B area are established dynamically or semi-statically.

<uplink control information>

The uplink control information is divided into first control information, second control information and third control information.

The first control information is directly related to transmission of uplink data, and a representative example is TFCI. The second control information is not directly related to transmission of uplink data, and a representative example is CQI or ACK/NACK. The third control information allows a base station (BS) to measure a channel of data transmitted to an uplink, and a representative example is a CQ pilot.

The present invention is equally applicable not only to the first to third control information but also to various control information transmitted to the uplink.

FIG. 2 is a schematic diagram illustrating an example of a resource allocation method from among the resource allocation methods of the present invention according to the present invention.

The downlink control information for scheduling uplink resources may include information associated with a method for allocating uplink resources. Specifically, if the control information is variable, the downlink control information may also include information indicating a resource transmission method capable of accommodating the variable control information.

<Block where uplink control information is desired to be transmitted>

According to the LTE assumption, a single uplink subframe includes 6 long blocks (LB) and 2 short blocks (SB). The number of LBs or SBs may be changed to the other at a later time, so that it is assumed that symbols for transmitting uplink control information are basically represented by LBs, however, the symbols may also be represented by SBs as necessary.

Generally, SBs are established under the assumption that reference signals are transmitted, so that it is difficult to add high-capacity control information (eg, CQI) to SBs. In other words, the SB is insufficient to additionally contain high capacity control information.

Therefore, uplink control information according to the present invention is basically transmitted via LB, however, it should be noted that low-capacity uplink control information (eg, ACK/NACK) may be transmitted not only via LB but also via SB.

<resource allocation method>

The resource allocation method can be divided into a partial transmission method and a repeated transmission method.

If the amount of uplink control information is greater than a predetermined level, the partial transmission method divides the uplink control information into several information units and transmits the divided information units so that the entire uplink control information is separately transmitted to a destination.

The repeated transmission method transmits control information N times on several symbols or several subframes so that it increases the reception reliability of the control information. For example, if the value of N is 2, the repeated transmission method may transmit the control information twice.

Part of the transmission method is suitable for transmitting relatively high capacity uplink control information (eg, CQI).

The repeated transmission method is used in a specific situation where the same control information (eg, ACK/NACK) has to be transmitted repeatedly according to system conditions.

However, the same resource allocation method is applied to the partial transmission method and the repeated transmission method, so that the following detailed description of the partial transmission method will replace the detailed description of the repeated transmission method.

<partial transfer method>

Relatively high capacity uplink control information such as CQI may not be simultaneously transmitted to a single resource region unit. In this case, a mobile station (MS) transmits corresponding uplink control information on a plurality of resource regions.

In this case, if the control information is variable so that it is larger than a basic unit for transmitting the control information, the partial transmission method may transmit the control information over several symbols or several subframes. In this case, it is basically assumed that control information between users is multiplexed according to a CDM (Code Division Multiplexing) or TDM (Time Division Multiplexing) scheme, so that the multiplexed Control information is passed to the user.

Specifically, the partial transmission method can extend a portion beyond a single basic transmission unit to the next basic transmission unit, and can also extend the above-mentioned portions to resource regions spaced apart from each other. In this case, the resource region means a region composed of a frequency region and a time region, and the basic size of the resource region can be established in different ways depending on system situations.

The amount of uplink control information fed back to a base station (BS) may increase or decrease due to changes in system conditions. A representative exemplary situation in which uplink control information is increased may be a specific situation in which a current single-antenna system is changed to a multi-antenna system such as a MIMO system.

For example, when comparing the first situation using the MIMO system with the second situation not using the MIMO system, the amount of feedback control information in the first situation may be much larger than that in the second situation. In more detail, B resource units are required for the first scenario employing the MIMO system, and A resource units are required for the second scenario not employing the MIMO system (where A≦B). In this case, a region for transmitting control information is extended so that the control information can be transmitted over several symbols or subframes.

For example, the system uses a DCT (Discrete Cosine Transform) based CQI transmission scheme as long as the control information transmitted to the uplink is CQI, and the transmitted CQI exceeds a single resource region, which is allocated to several resource regions (i.e. , several symbols or several subframes), and then transmit over several symbols or subframes.

For example, if CQIs are multiplexed according to the TDM scheme, and the number of DCT-processed CQIs is M, M/2 are allocated to the first subframe, and another M/2 are allocated to the second subframe . Preferably, if CQI accuracy is more important than system complexity, the CQI can be DCT-processed again for each subframe, and some parts of the DCT-processed CQI can be transmitted to the desired destination.

If the CQI is multiplexed according to the TDM scheme while using the best M CQI transmission methods, M/2 information from the M information are allocated to the first subframe, and another M/2 Information is allocated to the second subframe in order to transmit the CQI separately. If both the partial transmission method and the repeated transmission method are used, each information is repeated so that the repeated information is transmitted over four subframes. If a CDM scheme is used, the CQIs may be multiplexed simultaneously while maintaining orthogonality over the allocated resource regions, or be CDM-processed for each basic transmission unit so that the resulting CQIs are transmitted to the desired destination.

Meanwhile, although the same MIMO mode is provided, the amount of CQI fed back may be changed to another amount according to the class of the codeword being transmitted. In this case, the method for transmitting control information on the extended resource region can also be applied to the case where the above-described feedback CQI amount is changed to another amount according to the codeword class.

For example, if data is TDM multiplexed by a system equipped with a TTI consisting of two subframes, the system transmits CQI using only the first subframe during non-MIMO mode. Thereafter, if the non-MIMO mode is changed to the MIMO mode, the system allocates the CQI to two subframes so that it transmits the CQI on the two subframes. Needless to say, if the CQI includes four data streams, two data streams can be allocated to each subframe so that the four data streams can be transmitted via two subframes.

According to a Code Division Multiplexing (CDM) scheme, the CQI is CDM-processed over an extended resource region (for example, two subframes), or is CDM-processed for each basic transmission unit, so that the resulting CQI is transmitted to the desired destination.

The above partial transmission method can be extended to at least two subframes.

In other words, if the amount of feedback information to be transmitted is M, M-P1 (where P1≤M) is transmitted to the first subframe, and M-P1-P2 (where P2≤M) is transmitted to the second subframe, And M-P1-P2-PK (PK<M, P1+P2+P3+...+(the ellipsis is suspected in the original text) PK=M) is fed back to the Kth frame.

In the case of the CDM scheme, data is CDM-processed over all extended areas, or is CDM-processed for each basic transmission unit, so that the resulting data is transmitted to a desired destination.

<index transfer scheme>

As described above, the present invention determines whether the mobile station (MS) uses the non-MIMO mode or the MIMO mode, decides to repeatedly transmit the target information over an extended area according to the determined mode, or decides to transmit the target information separately so that it must notify The mobile station (MS) of the above decision result. Therefore, many different situations may arise that can dictate the above-mentioned decision, so that the amount of control information of the downlink channel inevitably increases.

Therefore, the present invention uses only one bit to indicate whether the mobile station (MS) is in MIMO mode or non-MIMO mode, uses only one bit to indicate whether control information is transmitted repeatedly, and uses only one bit to indicate whether control information is transmitted separately, so that it can represent all the different cases using index information consisting of 3 bits.

The present invention includes a table associated with the above-mentioned index information in each of a base station (BS) and a mobile station (MS), so that the amount of downlink channel control information can be reduced.

An exemplary index table for notifying ACK/NACK partial transmission and CQI partial transmission under the condition that the MIMO mode is notified in advance is shown in Table 1 below:

[Table 1]

index MIMO ACK/NACK repeated transmission CQI partial transmission 0 X x x 1 X o o 2 O x o 3 O o o

As long as the MIMO mode of the mobile station (MS) can be identified in advance, the above index table indicates whether ACK/NACK is repeatedly transmitted under the condition that only ACK/NACK has been designed to be repeatedly transmitted, or indicates whether only CQI has been designed Whether or not the CQI is partially transmitted on the condition that it is transmitted on the extended area.

<frequency hopping>

According to the partial transmission method described above, the parts transmitted over the extended area need not always be located on the same subframe, or at the same position within different subframes. Also, the repetition part for use in the repetition transmission method does not need to be located at the same position within the subframe.

FIG. 3 is a schematic diagram illustrating a repeated transmission method in a resource allocation method from the present invention.

As can be seen from FIG. 3, uplink control information (e.g., ACK/NACK or CQI) is transmitted from the frequency A region and hops onto the frequency B region during repeated transmission situations so that it is transmitted between the A and B regions. upload. In this case, the basic hopping period (ie, symbol, subframe and other specified length) can be established in various ways.

<Partial advance reservation method>

If the base station (BS) separately decides block information (SB or LB) for allocating uplink resources via downlink control information, repeated or partial transmission method, and positioning/allocation method, the base station (BS) smoothly allocates Uplink resources can be effectively used, however, the amount of downlink control information increases. Therefore, there is a need for an improved method capable of providing a predetermined level of flexibility to the above-described method for allocating uplink resources while reducing the amount of downlink control information.

Accordingly, different resource allocation methods are reserved between a base station (BS) and a mobile station (MS) according to the type of blocks used for uplink resource allocation and the type of uplink control information. The base station (BS) allocates resources according to the above-mentioned block of resource allocation method so that a trade-off between the first requirement for securing resource allocation flexibility and the second requirement for minimizing the amount of downlink control information is available.

<Maintain single carrier characteristics>

In order to maintain single-carrier characteristics between uplink control information blocks, CQ pilots are periodically transmitted to the uplink, allocated to a single symbol or all symbols (or a single block or all blocks) at the same time, and then transmitted to the desired destination. Preferably, ACK/NACK and CQI may not be simultaneously transmitted to different frequency bands.

As can be seen from FIG. 3 , the subframes in the case of transmission of CQ pilots are different from the subframes in the case of non-transmission of CQ pilots.

Therefore, as long as a subframe including a CQ pilot is called type A, and another subframe not including a CQI pilot is called type B, types A and B can be transmitted to various combination. For example, CQ pilots may be transmitted in the order A B B A B B. In other words, the CQ pilot may be transmitted periodically, or may also be transmitted aperiodically.

Preferably, single-carrier characteristics between uplink control information and uplink user data can be maintained. For example, there is no problem in the specific case where only control information is transmitted and no uplink data is contained. However, if a user has to transmit data and control information simultaneously, he or she may perform a single DFT on the transmission data or information to maintain a single frequency characteristic, and may transmit the DFT-processed result together with the transmission data or information.

It should be noted that most terms disclosed in the present invention are defined in view of the functions of the present invention, and may be determined differently according to the intention of those skilled in the art or custom. Therefore, the above terms are preferably understood based on all the contents disclosed in the present invention.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Industrial applicability

The present invention provides a method for adaptively allocating resources of an uplink control channel according to system conditions. The above method adaptively allocates uplink resources according to changes in the number of users included in the coverage of the base station and the amount of feedback information so that the resources can be effectively used, and between the mobile station (MS) and the base station (BS) communication throughput increases.

While preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various Modifications, additions and substitutions are all possible.

Claims (12)

1. A method of allocating resources for transmitting uplink control information using an uplink control channel in a mobile station (MS) of a mobile communication system, comprising: receiving, by the mobile station, control information established by a base station (BS), wherein the control information is established based at least on an amount of available resources; and Allocating resources of the uplink control channel according to the received control information, wherein the resources of the uplink control channel are separated in the frequency domain, wherein the resources are allocated to form information blocks in the uplink control information The single-carrier characteristic is maintained between them. 2. The method according to claim 1, wherein said resources for transmitting uplink control information are hopped from one frequency to another within a frequency hopping period. 3. The method of claim 1, wherein the received control information includes at least one of an amount of resources available for transmission of the uplink control information and a location of resources available for transmission of the uplink control information . 4. The method according to claim 3, wherein the information on the location of said resource further comprises information indicative of a resource allocation scheme. 5. The method according to claim 4, wherein if the amount of uplink control information to be transmitted is different from a basic resource allocation unit, the resource allocation scheme controls resource allocation area to be larger or smaller than the basic resource allocation unit, to accommodate the uplink control information. 6. The method according to claim 4, wherein said resource allocation scheme performs resource allocation such that said uplink control information is repeatedly transmitted over several symbols or subframes. 7. The method of claim 1, further comprising allocating the resource to an entire portion of a single block if the uplink control information is a pilot for channel estimation. 8. The method of claim 1, wherein said resources for transmitting uplink control information are allocated to maintain single carrier characteristics between said uplink control information and uplink data. 9. The method according to claim 1, further comprising: multiplexing the uplink control information with other control channels, and and transmitting the multiplexed uplink control information. 10. A method of transmitting downlink control information in a base station (BS) of a mobile communication system to allocate resources for transmitting the uplink control information using an uplink control channel, comprising: generating, by a base station (BS), downlink control information for allocating resources for transmission of the uplink control channel, wherein the uplink control information is generated based at least on an amount of available resources; and transmitting said downlink control information to a mobile station (MS), wherein the resources of the uplink control channel are separated in the frequency domain, wherein the resources are allocated to maintain single-carrier characteristics between constituent information blocks of the uplink control information, and The resources are determined according to the downlink control information. 11. The method according to claim 10, wherein said resources for transmitting uplink control information are hopped from one frequency to another within a frequency hopping period. 12. The method according to claim 11, wherein said downlink control information comprises at least one of an amount of resources available for transmission of said uplink control information and a location of resources available for transmission of said uplink control information one.