KR101389393B1 - System and method for resource allocation of common feedback channels for cooperative beam-forming based interference coordination in wireless communication system - Google Patents

Abstract

The present invention relates to a wireless communication system and, more specifically, to a system for allocating common channels feedback resources sharing limited feedback channel resources and the derivation of channel feedback resource amount required for cooperative beamforming in resources environment for limited channel feedback between cooperative transmitting ends. According to the present invention, for a method of transferring information between each transmitting end and receiving end, a user can be effectively provided with a method of operating resources required for transferring corresponding information and a method of transferring information required for each transmitting end in each receiving end as compared to a previous method. [Reference numerals] (S600) Desired channel gain by MS(Central Quality information, CQI), information required amount (QoS), interference channel gain (CQI) information feedback; (S610) Sharing the information between BS(Central/Distributed) Scheduling; (S611) Calculating the feedback resources and the allocation amount; (S612) Transferring allocation information to the MS; (S620) Channel direction information feedback(Codebook based) by MS; (S630) Transferring the data based on beamforming

Description

System and Method for resource allocation of common feedback channels for cooperative beam-forming based interference coordination in wireless communication system

The present invention relates to a wireless communication system, and more particularly, to a common channel feedback resource allocation system for deriving the amount of channel feedback resources required for cooperative beamforming in a limited channel feedback resource environment and sharing the limited feedback channel resources among cooperative transmitters. It is about.

The present invention also relates to a method of allocating a channel feedback resource amount required for cooperative beamforming in a limited channel feedback resource environment and sharing a limited feedback channel resource among cooperative transmitters.

Multi-input multi-output (MIMO) technology as a way to overcome the limitations of communication capacity due to interference of transmission signals when there are multiple transmitters (base stations, BSs) in a wireless communication system Antenna beamforming based interference control technique is considered.

Figures showing this are shown in Figs. Referring to the drawings, cooperative beamforming is performed in an interference channel environment of a plurality of transmitters 101 and 102 and terminals 121 and 122.

There is a method of utilizing spatial null space of a channel based on channel information of an interference signal during beamforming using multiple antennas. This beamforming technique is called zero-forcing (ZF), and the beamforming can be removed by projecting the beamforming based on the spatial zero space of the interference signal.

Techniques for showing these include T. Yoo and A. Goldsmith, "On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming", IEEE J. Select. Areas Commun., Vol. 24, pp.528-541, Mar. 2006. and 2. T. Yoo, N. Jindal, and A. Goldsmith "Multi-antenna downlink channels with limited feedback and user selection", IEEE J. Select. Areas Commun., Vol. 25, no. 7, pp. 1478-1491, Sep. 2007. etc. are mentioned.

The transmission beamforming-based interference control scheme is a system that applies the ZF scheme at the transmitter, and when the transmitter uses multiple antennas and the receiver (terminal, mobile station, MS) has one antenna, the signal from the transmitter to the receiver is transmitted. This method is to control the interference experienced by each receiver by designing the transmission beamforming based on the ZF technique by acquiring channel information. Such transmission beamforming-based interference control schemes can be considered in all cellular systems besides Ad-hoc systems. This transmission beamforming based interference control scheme is referred to as a cooperative beamforming system.

The channel information acquisition scheme for the transmission cooperative beamforming may be configured in various ways. However, in a frequency division duplex (FDD) system where uplink / downlink frequency bands are difficult to estimate channel information at the transmitting end, uplink It can be obtained from the transmitter by feeding back from the receiver to the transmitter through the resources of

In the cooperative beamforming system, channel information fed back from each receiver may be divided into channel feedback directed to a transmitter of a corresponding receiver and interference channel feedback to an interference transmitter that forms interference.

In general point-to-point communication (P2P) systems that do not generate interference signals, interference channel feedback is not required. In interference limited (interference limited, interference channel) systems utilizing cooperative beamforming, additional interference control is required. Feedback resource allocation is required.

In this case, uplink resources for channel information feedback are limited, and in particular, uplink resources have a bandwidth allocation limitation in ad-hoc and cellular cooperative beamforming systems in which frequency resources of a transmitter / receiver are shared.

Techniques to demonstrate this include K. Huang, VKN Lau, and D. Kim, "Event-Driven optimal feedback control for multi-antenna beamforming", IEEE Transactions on Signal Proc., Vol. 58, no. 6, pp. 3298- 3312, Jun. 2010. and R. Bhagavatula and R. W. Heath Jr., "Adaptive bit partitioning for multicell intercell interference nulling with delayed limited feedback", IEEE Transactions on Signal Proc., Vol. 59, no. 10, pp.3824-3836, Oct. 2011. etc. are mentioned.

This allocation limit limits the accuracy of channel information and is a factor that limits the performance of the ZF scheme. In general, the magnitude of the channel feedback information is proportional to the SNR. For example, when the SNR is 10 dB, the channel feedback information takes about 100 bits to ensure accuracy, but since the link resources are limited, the transmission of the channel feedback information is limited.

Therefore, when resources for channel information delivery are limited, there is a need for a method of utilizing these resources more efficiently. The limited channel feedback resource utilization method has been studied in various ways and can be summarized as follows.

First, all the channel feedback resources allocated to each receiver are the same, and the amount of channel feedback information of each receiver is also equally assigned to each transmitter. The additional information and various feedback information-codebooks according to the allocation are designed. Not required.

Secondly, all channel feedback resources allocated to each receiver are identically set, but each terminal randomly allocates channel feedback resources according to the magnitude of interference. There is a need for utilization, but relatively efficient resource allocation is possible.

The limitations of these technologies are as follows.

In case of the first technique, resource allocation considering the required information transmission amount of each receiver is not considered in resource allocation, and thus more channel feedback resources are required for the performance of the same communication system because the resource allocation of channel feedback is collectively applied. Do.

In case of the second technology, an allocation problem has been proposed under the premise that resource allocation is randomly allocated from the viewpoint of a receiving end in terms of resource allocation, and that the resource allocation amount per terminal is the same.

The above technique does not consider that the system-specific channel feedback resources required for the cooperation of the entire system are limited, and the efficient allocation of feedback resources is achieved by not considering the different required SINRs of each receiver in the feedback resource allocation. Not proposed. In addition, since the receiver randomly allocates channel feedback, it is necessary to convey information about an additional codebook.

Finally, both technologies do not derive the necessary feedback resources needed to operate the entire system, and thus there is a limit in not using the limited resources of the entire system efficiently.

1. Korean Patent Publication No. 10-2008-0051494 2. Korean Patent No. 10-0870471

1. T. Yoo and A. Goldsmith, "On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming", IEEE J. Select. Areas Commun., Vol. 24, pp.528-541, Mar. 2006. 2. T. Yoo, N. Jindal, and A. Goldsmith "Multi-antenna downlink channels with limited feedback and user selection", IEEE J. Select. Areas Commun., Vol. 25, no. 7, pp. 1478-1491, Sep. 2007. K. Huang, VKN Lau, and D. Kim, "Event-Driven optimal feedback control for multi-antenna beamforming", IEEE Transactions on Signal Proc., Vol.58, no.6, pp.3298-3312, Jun . 2010. 4. R. Bhagavatula and R. W. Heath Jr., "Adaptive bit partitioning for multicell intercell interference nulling with delayed limited feedback", IEEE Transactions on Signal Proc., Vol. 59, no. 10, pp.3824-3836, Oct. 2011.

The present invention is proposed to solve the problems according to the background art described above, and it is possible to derive a channel feedback resource amount required for cooperative beamforming in a limited channel feedback resource environment and to operate a system for sharing limited feedback channel resources among cooperative transmitters. An object of the present invention is to provide a common channel feedback resource allocation system and method for cooperative beamforming based interference control in a wireless communication system.

In addition, the present invention provides cooperative beamforming-based interference control in a wireless communication system that allows resource allocation according to a request information transmission amount, service probability (Outage), and size of a signal and an interference channel in the proposal of limited feedback resource allocation. It is another object of the present invention to provide a system and method for allocating a shared channel feedback resource.

Another object of the present invention is to provide a system and method for allocating a common channel feedback resource for cooperative beamforming based interference control in a wireless communication system for allocating common resources according to channel feedback resource allocation derivation required for interference control. have.

The present invention provides a cooperative beam in a wireless communication system that enables the derivation of the amount of channel feedback resources required for cooperative beamforming in a limited channel feedback resource environment and a system operation for sharing limited feedback channel resources among cooperative transmitters. A common channel feedback resource allocation system for forming based interference control is provided.

The common channel feedback resource allocation system,

A plurality of receivers for generating their own channel feedback information; And

A plurality of transmitters generating channel quality information and an estimated channel of each of the receivers using the channel feedback information, and setting cooperative beamforming to perform interference control on the receivers using multiple antennas. It may be characterized by including;

In this case, the channel feedback information may include the size of its own interference channel, the size of the signal channel and the amount of necessary information transmission.

In addition, the plurality of transmitters may share the channel feedback information with each other to calculate a resource required for the interference control to derive and allocate an amount of channel feedback resource required for the cooperative beamforming.

In addition, the channel feedback resource amount may be differentially allocated using a required signal-to-interference-plus-noise ratio (SINR) value and the magnitude of the interference.

In addition, as the required signal-to-interference-plus-noise ratio (SINR) value and the magnitude of the interference are larger, more resources may be allocated.

In addition, the channel feedback resource amount may be differentially allocated using an stability value.

In addition, the smaller the stability (outage) and the size of the receiving channel may be characterized by allocating more resources.

In addition, the size of the interference channel, the size of the signal channel and the amount of necessary information transmission may be characterized by using the value at the instant of the communication or the average value.

In addition, if the allocation operation of the plurality of receivers is known in advance, only the total size may be allocated to reduce the information amount of the channel feedback resource amount.

In addition, generation of the channel feedback information of the plurality of receivers may be characterized by using random vector quantization (RVQ).

In addition, the random vector quantization may be selected from a randomly generated codebook known to both the transmitter and the receiver.

In addition, the sharing of the channel feedback information with each other may be shared by utilizing a cooperative feedback resource or transmitting the data through a backhaul.

On the other hand, an embodiment of the present invention,

Generating channel feedback information of a plurality of receivers;

Generating, by a plurality of transmitters, channel quality information and an estimated channel of each of the receivers using the channel feedback information; And

And performing cooperative beamforming using the multiple antennas by setting cooperative beamforming using the channel quality information and the estimated channel generated by the plurality of transmitters, and performing interference control on the plurality of receivers. A method of allocating a common channel feedback resource for interference control is provided.

According to the present invention, in a method of transferring information between each transmitting end / receiving end, it is possible to provide a user with a method of delivering information necessary for each transmitting end in each receiving end more efficiently than the previous method and a method of operating necessary resources for transmitting the corresponding information. have.

Another effect of the present invention is that it can provide a user with a method of designing a cooperative wireless communication system which requires less channel feedback resources than the previous scheme.

In addition, another effect of the present invention is that in the cooperative beamforming system, a user may be presented with a scheme for allocating feedback resources and deriving resource requirements according to a required transmission amount or a target SINR of a receiver. have.

1A and 1B show an example in which cooperative beamforming is generally implemented in an interference channel environment.
FIG. 2 is a diagram illustrating a process of allocating channel information feedback resource for transmitting channel information and transferring information of feedback in the system illustrated in FIGS. 1A and 1B.
3 is a configuration example of a cooperative feedback resource in a cooperative beamforming system in an interference channel environment according to an embodiment of the present invention.
4 is an embodiment of a method of allocating cooperative feedback resources in a frame of a typical communication system.
5 is an illustration showing a process of allocating channel information feedback resource for transmitting channel information and delivering information of feedback according to an embodiment of the present invention.
6 is a flowchart showing the flow of system operation according to an embodiment of the present invention.
FIG. 7 is a result of performance verification through simulation according to an embodiment of the present invention. FIG. 7 is a comparison graph of stability performance of a system compared to existing feedback resource allocation in the environment of Tables 1 and 2. FIG.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Like reference numerals are used for similar elements in describing each drawing.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Should not.

Hereinafter, a common channel feedback resource allocation system and method for cooperative beamforming based interference control in a wireless communication system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a configuration example of a cooperative feedback resource in a cooperative beamforming system in an interference channel environment according to an embodiment of the present invention. Referring to FIG. 3, the common channel feedback resource allocation system 300 assumes a wireless communication situation in which a plurality of transmitting terminals 301 and 302 and a receiving terminal 321 and 322 communicate through the same resource.

The transmitting end 301, 302 is composed of a first transmitting end 301, a second transmitting end 302, and the like, and may mean a base station BS in a conventional sense, but is not limited thereto.

The receiving end 321, 322 is composed of a first receiving end 321, a second receiving end 322, and the like, which may mean a terminal MS in a conventional sense, but is not limited thereto.

In addition, the transmitter / receiver includes a multi-antenna multi-antenna transmission and / or an environment in which a single-antenna receiver intends to communicate with each other in an Ad-hoc environment.

The basic mode of operation according to an embodiment of the present invention is a vector channel through a plurality of antennas in a technique of estimating channel information through a technique commonly used by each receiving end 321 and 322 and transmitting it to each transmitting end 301 and 302. Suppose a system that delivers an explicit feedback through a codebook.

This is a conventional codebook based channel feedback scheme. In general, sounding-based feedback (implicit feedback) relates to the length and resources of the sounding and can be applied in a general sense. Accordingly, an embodiment of the present invention provides an implementation implemented based on a codebook based channel feedback scheme.

는 벡터

의 크기(norm)를 의미하며,

는 Hermitian 연산을 의미한다. 또한,

은 구성 element 수가

개의 복소수를 가지는 벡터를 의미한다. In one embodiment of the invention,

Vector

Means the norm,

Means Hermitian operation. Also,

Is the number of elements

Means a vector with two complex numbers.

개의 송신단(301,302)이 동시에 같은 주파수 자원을 통해 각각의 수신단(321,322)으로 신호를 전송하는 경우

번째 수신단의 관점에서 수신하는 수신 신호는 다음식과 같이 나타낼 수 있다.Referring to the basic operation pattern of the system according to an embodiment of the present invention, in the system for controlling the interference through the beamforming of multiple antennas based on the channel information in the cooperative beamforming system

When two transmitters 301 and 302 simultaneously transmit signals to the receivers 321 and 322 through the same frequency resource

The received signal received from the viewpoint of the first receiver can be expressed as follows.

[Equation 1]

는 수신단과 송신단의 인덱스이며,

는

번째 송신단에서

번째 수신단으로의 채널 벡터이다. In this case, the transmitting end 301, 302 may be regarded as a base station and the receiving end 321, 322 as a terminal.

Is the index of the receiver and transmitter,

The

On the first sender

Is the channel vector to the first receiver.

을 전달하는

번째 송신단의 빔포밍 벡터

는 간섭을 제어하기 위함이며 이는 각 수신단의 채널 피드백 정보를 기반으로 한다. In the case of Equation 1, information of the receiving end

To pass

Beamforming vector of the first transmitting end

Is for controlling interference, which is based on channel feedback information of each receiver.

번째 수신단에 정보를 전달하지 않는 송신단의 간섭을 제어하기 위하여

번째 수신단이 피드백한 채널 정보를 기반으로 간섭 제어(310)를 실시한다. The second term on the right side of Equation 1 means an interference signal

To control the interference of the transmitter that does not transmit information to the first receiver

The interference control 310 is performed based on the channel information fed back by the first receiver.

번째 송신단에 대하여 다음과 같은 수학식으로 표현 가능하다.Such interference controlled beamforming is random

The first transmitting end can be expressed by the following equation.

&Quot; (2) "

번째 송신단은 채널의 방향 벡터

for all

을 알아야 한다. Thus random

Is the direction vector of the channel

for all

Should know.

In an embodiment of the present invention, a limited feedback resource is assumed, and as an embodiment, a system using random vector quantization (RVQ) is assumed as a channel feedback technique of a receiver in order to explain an allocation pattern of limited feedback resource. .

으로부터 선택된다. 채널 피드백의 정보량

(단위 bit)가 주어질 때, 코드북의 크기는

이다. Random vector quantization is a randomly generated codebook known to both the transmitter and the receiver.

. Information amount of channel feedback

Given a unit bit, the size of the codebook

to be.

는 복소수 단위원으로부터 균일하게 선택되어진다. 즉,

로 표현될 수 있다.

번째 수신단은 임의의 채널 벡터

의 피드백 벡터

을 수학식 3과 같은 방법으로 선택한다.Each vector

Is uniformly selected from complex unit sources. In other words,

It can be expressed as.

The first receiver is any channel vector

Feedback vector

Is selected in the same manner as in Equation 3.

&Quot; (3) "

번째 수신단은

의 색인을

번째 송신단으로 피드백하며, 송신단은 채널 품질 정보와

로부터

번째 수신단으로의 채널

을 추정한다. 추정된 채널과 채널 품질 정보를 통해 송신단은 빔포밍을 설계한다.

The first receiver is

Index of

To the first transmitting end, which sends the channel quality information

from

To the first receiver

. Through the estimated channel and channel quality information, the transmitter designes beamforming.

을 채널에 따라 다르게 할당할 수 있으며, 송신단은 이러한 피드백 정보를 따라 다른 정확도로 채널

을 알 수 있으며, 이는

할당된 정보량

에 의해 결정된다.As an essential point in one embodiment of the present invention, each receiving end is the amount of feedback information that conveys such channel information.

Can be assigned differently according to the channel, and the transmitting end can follow the feedback information and the channel with different accuracy.

It can be seen that

Amount of information allocated

.

번째 수신단의 한정된 채널 피드백 정보량에 따른

번째 송신단에서 들어오는 잔여 간섭신호의 유효 채널 크기는 다음과 같이 표현될 수 있다.At this time

According to the limited amount of channel feedback information of the first receiver

The effective channel size of the residual interference signal coming from the first transmitter may be expressed as follows.

&Quot; (4) "

개의 안테나를 전송하며, 채널 벡터

에 할당된

값을 할당했을 때의 경우를 나타낸 경우이다. In the above equation, the transmitting end

Transmit antennas, channel vector

Assigned to

This is the case when the value is assigned.

Therefore, the interference signal is not completely eliminated according to the limited channel information amount allocation. Unlike a system capable of providing infinite channel information feedback, in order to control residual interference due to limited resources, an efficient resource allocation is performed by allocating channel information feedback resources according to channel size and required SINR value in consideration of limited resources.

In this case, as information required for the feedback resource allocation scheme described below, information transmission such as transmission channel direction, channel quality information (CQI), stability, and required signal-to-noise ratio, which are not mentioned in the description of the present invention, may be performed. It may be configured in a conventional manner, and the information transmission may also be transmitted to each transmitter through the proposed shared feedback resource.

로 정의한다. 이때, 제한된 채널 피드백 자원은 다음과 같은 수학식으로 표현될 수 있다. It is assumed that feedback to a transmitter that transmits a signal of each receiver is transmitted in a conventional manner. Therefore, an embodiment of the present invention considers resource management for interference channel feedback, which is an additional resource required for cooperative beamforming for interference control, and considers the total amount of interference channel feedback resources in the cooperative beamforming based interference control system.

. In this case, the limited channel feedback resource may be expressed by the following equation.

Equation 5a

[Equation 5b]

bit로 한정되며, 이때, 각 수신단이 활용할 수 있는 자원량은

bit, 다시 각 수신단이 각 송신단으로 전송하는 채널 정보의 정보량은

bit이다.As shown in Equation 5, the feedback resource is

limited to bits, and the amount of resources available to each receiver is

bit, and the information amount of channel information transmitted from each receiver to each transmitter is

bit.

Next, a basic operation mode of the feedback resource allocation scheme according to an embodiment of the present invention will be described.

In an embodiment of the present invention, in forming a cooperative beamforming system between transmitters, a system for allocating a resource related to a feedback channel between each transmitter and receiver from channel feedback resources of the entire cooperative transmitter is proposed as shown in FIG. Can be.

4 is an embodiment in which the allocation of shared resources for feedback of an interference channel is represented by a communication frame structure when a cooperative beamforming system is formed. Referring to FIG. 4, the communication frame 400 includes header information 410, cooperative feedback resource information 420, media access control (MAC) information 430, and the like. Here, the communication frame 400 may be an orthogonal frequency division multiple access (OFDMA) frame.

5 is an illustration showing a process of allocating channel information feedback resource for transmitting channel information and delivering information of feedback according to an embodiment of the present invention. That is, information exchange and communication are performed through the process as shown in FIG. 5.

Referring to FIG. 5, first, each receiver transmits the size of its own interference channel, the channel quality information (CQI), and the amount of necessary information transmission to each transmitter, and based on this, each transmitter controls interference of each receiver. Calculate and allocate the necessary resources.

Here, the representative parameter of the quality of service (QoS) may be a signal-to-interference-plus-noise ratio (SINR), and may be an outage value if necessary.

This has the following difference compared to the process of FIG. 2 discussed in the background. First, the required resource is derived based on the channel size value and the required information transmission amount, which are information commonly used in the background art, and this may use an immediate value or an average value at the instant of communication (501 of FIG. 5).

Thereafter, each transmitting end 301 or 302 transmits resource values allocated to each receiving end 321 and 322 (502 in FIG. 5). This may only allocate the entire size of the resource or inform all of the values according to the channel. However, when the allocation operation of the receiving end is known in advance, only the entire size may be allocated to reduce the amount of resource allocation information.

Thereafter, the receivers 321 and 322 feed back channel information to the transmitters 301 and 302 using the shared resources within the information amount allocated to the different information amounts (503 in FIG. 5). The above-mentioned information flow is characterized in that each base station (301, 302 of FIG. 5) is obtained through the cooperative feedback resource information 420 of the communication frame 400 shown in FIG.

6 is a flow chart showing the overall system operation flow in accordance with one embodiment of the present invention. Referring to FIG. 6, each receiving end 321, 322 feeds back desired channel quality (CQI), information request amount (QoS), and interference channel gain (CQI) information to each base station 301, 302 (step S600).

Each transmitting station 301, 302 performs information sharing and / or scheduling between transmitting stations (step S610).

Thereafter, each transmitting station 301, 302 derives a feedback resource amount and an allocation amount for each transmitting station (step S611). The information required for the method of deriving the feedback resource is obtained through the information acquisition process of 501 of FIG. 5. This includes transmitting the data through other methods.

As an example of deriving the interference channel information feedback resource for operating the cooperative beamforming system, as an embodiment of deriving the total channel feedback resource value required for the operation of the cooperative beamforming system, the following equation may be used.

&Quot; (6) "

는 송신단의 인덱스이고, 각 변수 값

는

번째 수신단의 간섭 채널 크기/품질 값의 기하 평균,

는 필요 신호 대 잡음비,

는

번째 송신단으로부터의 채널 크기, 마지막으로

는

번째 수신단의 필요 outage의 값이다. At this time

Is the index of the sending end, and the value of each variable

The

Geometric mean of the interference channel size / quality value of the first receiver,

Need signal to noise ratio,

The

Channel size from the first sender, finally

The

Value of the required outage of the first receiver.

)을 도출할 수 있으며, 이를 위해 필요로 하는 정보는 필요 신호 대 잡음비, 간섭 채널의 크기의 기하 평균 및 수신 채널의 크기 및 필요 outage 값을 이용하는 것을 특징으로 한다. Therefore, channel feedback resources necessary for the operation of the cooperative interference control through the above embodiment (

The information required for this purpose is characterized by using the required signal-to-noise ratio, the geometric mean of the size of the interference channel, the size of the receiving channel and the required outage value.

This means that the larger the size of the required signal-to-noise ratio and the interference channel, the more resources are allocated, and the smaller the size of the required outage and the receiving channel, the more resources are allocated. In addition, the proposed scheme encompasses deriving the necessary feedback resources using some or average of these values.

Derived Resource Based Channel Feedback Resource Derivation Assigned to Each Terminal and Feedback Resource Utilization Scheme for Each Terminal, Specific Channel Feedback Resource Allocation Scheme for Each Receiver and its Embodiment will be described with reference to FIG. 6.

번째 수신단에 대하여 채널 피드백 자원

을 할당할 수 있다.

값을 기반으로 각 단말에 대한 채널 피드백 자원 할당 방안으로는 다음식과 같은 방식을 들 수 있다. Based on the resource value derived through Equation 5

Feedback resource for the first receiver

. ≪ / RTI >

A channel feedback resource allocation scheme for each terminal based on the value may be as follows.

&Quot; (7) "

을 효율적으로 할당한다(단계 S612).A limited resource value by allocating different feedback resource resources to each receiving end 321 and 322 in the same manner as in Equation (7).

Is allocated efficiently (step S612).

In addition, as an embodiment of the proposed scheme, the channel feedback resource is allocated to each of the receivers 321 and 322 by utilizing the size of the channel and the required information transmission information.

로 채널 정보를 피드백한다(단계 S620). Finally, each receiver 321, 322 has a different amount of resources for the transmitter 301, 302 causing interference.

Channel information is fed back (step S620).

만큼의 채널 피드백 자원이 주어졌을 때,

번째 송신단(301,302)에서 전송하는

번째 간섭 송신단에 대한 채널 피드백 자원량

는 다음과 같은 실시예를 들 수 있다. 이와 같은 경우는 수신단(321,322)의 할당된 채널 피드백 자원 내에서 각 송신단(301,302)으로 보내는 자원 비율을 자동적으로 조절하는 방식이 된다.

Given as many channel feedback resources,

Transmitted from the first transmitting end (301, 302)

Amount of channel feedback resource for the first interfering transmitter

Examples include the following examples. In such a case, the ratio of the resources sent to the transmitters 301 and 302 within the allocated channel feedback resources of the receivers 321 and 322 is automatically adjusted.

&Quot; (8) "

는

번째 송신단에서

번째 간섭 송신단으로의 채널의 크기를 나타낸다. At this time

The

On the first sender

Represents the size of the channel to the first interfering transmitter.

Finally, the transmitting end 301, 302 performs beamforming based data transmission (step S630).

FIG. 7 is a result of performance verification through simulation according to an embodiment of the present invention. FIG. 7 is a comparison graph of stability performance of a system compared to existing feedback resource allocation in the environment of Tables 1 and 2. FIG.

In order to check the performance of an embodiment of the present invention, a test of resource allocation performance was performed in the environment shown in Table 1 below. The 802.16 channel pathloss model was used.

parameter value Cooperating BS number 3 Distance between cooperation MS 500 m Center frequency 2 GHz Pathloss Model 128.1 + 37.6 log 10 (distance) BS antenna number 4

The distance and required signal-to-noise ratio of each receiver are shown in Table 2 below.

Case Item Receiver 1 Receiver 2 Receiver 3 Case 1 Distance to signal transmission transmitter 450 m 450 m 450 m Signal to Noise Ratio Needed 5dB 5dB 5dB Case 2 Distance to signal transmission transmitter 450 m 450 m 450 m Signal to Noise Ratio Needed 5dB 10dB 15 dB Case 3 Distance to signal transmission transmitter 350m 400m 450 m Signal to Noise Ratio Needed 5dB 5dB 5dB Case 4 Distance to signal transmission transmitter 350m 400m 450 m Signal to Noise Ratio Needed 5dB 10dB 15 dB

Using Table 1 and Table 2 above was divided into three experiments.

1) According to FIGS. 1 and 2, all channel feedback resources are allocated equally as in the following equation.

&Quot; (9) "

을 동일하게 두되,

할당에 대하여 다음식을 활용하는 경우. 2) otherwise, each terminal feedback resource

Leave the same,

Use the following equation for assignment.

&Quot; (10) "

3) Allocating channel feedback resources according to an embodiment of the present invention.

값을 기준으로 시스템의 안정적인 운용을 확인해 보았다. 도 7을 참조하면, 본 발명의 일실시예를 활용하였을 때, 피드백 자원 할당의 부족으로 인하여 간섭이 조절 되지 않아 시스템이 운용되지 않을 확률(outage)이 기존 방안들 대비하여 낮은 것을 확인 할 수 있다.First of all, to determine the performance gain,

Based on the values, we confirmed the stable operation of the system. Referring to FIG. 7, when using an embodiment of the present invention, the interference is not adjusted due to the lack of feedback resource allocation, and thus the probability that the system will not operate is low compared to the existing schemes. .

Accordingly, it can be confirmed that more efficient feedback resource allocation has been made through an allocation scheme according to an embodiment of the present invention.

In particular, the method for allocating a common channel feedback resource for cooperative beamforming based interference control according to an embodiment of the present invention may be implemented in program command code form that can be executed by various computer means and recorded in a computer readable storage medium. have.

The computer-readable storage medium may include program instructions, data files, data structures, and the like, alone or in combination.

The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software.

Examples of computer-readable storage media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magneto-optical media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

The medium may be a transmission medium such as an optical or metal line, a wave guide, or the like, including a carrier wave for transmitting a signal designating a program command, a data structure, or the like.

Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

In addition, one embodiment of the present invention may be implemented in hardware, software, or a combination thereof. (DSP), a programmable logic device (PLD), a field programmable gate array (FPGA), a processor, a controller, a microprocessor, and the like, which are designed to perform the above- , Other electronic units, or a combination thereof.

In a software implementation, it may be implemented as a module that performs the functions described above. The software may be stored in a memory unit and executed by a processor. The memory unit or processor may employ various means well known to those skilled in the art.

101,102: transmitter
121,122: receiving end
300: common channel feedback resource allocation system
301,302: sender
321,322: receiver
400: communication frame
410: header information
420: Collaboration feedback resource information
430: Media Access Control (MAC) information

Claims (22)

A plurality of receivers for generating their own channel feedback information; And
A plurality of transmitters generating channel quality information and an estimated channel of each of the receivers using the channel feedback information, and setting cooperative beamforming to perform interference control on the receivers using multiple antennas. Including;
The channel feedback information includes the size of its own interference channel, the size of the signal channel and the amount of necessary information transmission,
The plurality of transmitters share the channel feedback information with each other, calculate a resource required for the interference control, derive and allocate a channel feedback resource amount required for the cooperative beamforming,
And differentially allocating the channel feedback resource amount using a required signal-to-interference-plus-noise ratio (SINR) value and the magnitude of the interference.
delete delete The method of claim 1,
12. A common channel feedback resource allocation system for cooperative beamforming based interference control, characterized in that more resources are allocated as a required signal-to-interference-plus-noise ratio (SINR) value and the magnitude of interference are larger. The method of claim 1,
The common channel feedback resource allocation system for cooperative beamforming based interference control, wherein the channel feedback resource amount is differentially allocated using an stability value.
The method of claim 5, wherein
12. A common channel feedback resource allocation system for cooperative beamforming based interference control, characterized in that more resources are allocated as stability and size of the receiving channel are smaller.
The method of claim 1,
And the size of the interference channel, the size of the signal channel, and the amount of information transmission required are based on the instantaneous or average value of the communication.
The method of claim 1,
If the allocation operation of the plurality of receivers is known in advance, the common channel feedback resource allocation system for cooperative beamforming-based interference control, characterized in that to reduce the amount of information of the channel feedback resource amount by allocating only the total size.
The method of claim 1,
The generation of the channel feedback information of the plurality of receivers uses random vector quantization (RVQ), wherein the joint channel feedback resource allocation system for cooperative beamforming-based interference control.
The method of claim 9,
The random vector quantization is selected from a randomly generated codebook that is known to both the transmitter and the receiver, the common channel feedback resource allocation system for cooperative beamforming based interference control.
The method of claim 1,
The common channel feedback resource allocation system for cooperative beamforming based interference control, wherein the sharing of the channel feedback information with each other is shared by utilizing a cooperative feedback resource or transmitting it through a backhaul.
Generating channel feedback information of a plurality of receivers;
Generating, by a plurality of transmitters, channel quality information and an estimated channel of each of the receivers using the channel feedback information; And
And establishing cooperative beamforming by using the generated channel quality information and the estimated channel, and performing interference control on the plurality of receivers by using multiple antennas.
The plurality of transmitters share the channel feedback information with each other, calculate a resource required for the interference control, derive and allocate a channel feedback resource amount required for the cooperative beamforming,
And a method of differentially allocating the channel feedback resource amount by using a required signal-to-interference-plus-noise ratio (SINR) value and the magnitude of the interference.
delete delete 13. The method of claim 12,
A method for allocating a common channel feedback resource for cooperative beamforming-based interference control, characterized by allocating more resources as a required signal-to-interference-plus-noise ratio (SINR) value and the magnitude of interference are large.
13. The method of claim 12,
And a method of differentially allocating the channel feedback resource amount using an outage value.
17. The method of claim 16,
A method for allocating a common channel feedback resource for cooperative beamforming based interference control, characterized by allocating more resources as stability and a size of a reception channel are smaller.
13. The method of claim 12,
The size of the interference channel, the size of the signal channel, and the amount of information transmission required is a common channel feedback resource allocation method for cooperative beamforming based interference control, characterized in that using the instantaneous value or the average value of the communication. 13. The method of claim 12,
If the allocation operation of the plurality of receivers is known in advance, allocating only a total size to reduce the amount of information of the channel feedback resource amount.
13. The method of claim 12,
The generation of the channel feedback information of the plurality of receivers uses random vector quantization (RVQ).
21. The method of claim 20,
The random vector quantization is selected from a randomly generated codebook that is known to both the transmitting end and the receiving end.
13. The method of claim 12,
The sharing of the channel feedback information to each other is shared channel feedback resource allocation method for cooperative beamforming based interference control, characterized in that shared by using a cooperative feedback resource or transmitted through a backhaul (backhaul).

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