KR20130096514A - Communication method for relay networks - Google Patents

Abstract

PURPOSE: A communication method of a relay network is provided to show high reliability and performance in the relay network. CONSTITUTION: A relay network comprises a source node, a first relay node, a second relay node, and a destination node. The source node broadcasts a polarized information orthogonal frequency division multiplexing (OFDM) block to each of the first node and the second node (S410). The first relay node processes the broadcasted OFDM block (S420). The second relay node processes the broadcasted OFDM block (S430). The first relay node transmits the processed OFDM block to the destination node (S440). The second relay node transmits the processed OFDM block to the destination node (S450). [Reference numerals] (AA) Start; (BB) End; (S410) Source node broadcasts a polarized information orthogonal frequency division multiplexing (OFDM) block to each of the first node and the second node; (S420) Relay node processes the broadcasted OFDM block; (S430) Second relay node processes the broadcasted OFDM block; (S440) Relay node transmits the processed OFDM block to the destination node; (S450) Second relay node transmits the processed OFDM block to the destination node; (S460) Destination node decodes OFDM blocks received from first and second relay nodes; (S470) OFDM blocks decoded from destination node decodes are depolarized

Description

Communication method for relay network {Communication method for Relay Networks}

The present invention relates to a communication method of a relay network, and more particularly, to a communication method of a relay network including a source node, a first relay node, a second relay node and a destination node.

Channel polarization shows the structure of a verifiable capacity-achieving coding sequence that includes a Belief Propagation (BP) decoder. Channel polarization provides a potential way to meet the difficult objectives of multi-fold binary-input discrete memoryless channels, where channel combining and channel separation The channel splitting operation is applied to increase the symmetry capacity. Indeed, polarization of multiple channels is a common occurrence, so if several channels are mixed in an arrangement at the proper density, it is almost impossible to eliminate the polarization. In the past decade, space time coding (STC) communication systems have been studied as a way to increase bandwidth efficiency, channel capacity and link reliability. This indicates that coding gain and diversity can be achieved at the same time in an appropriate coding scheme. The problem with the relay method is data rate loss due to an increase in the number of relay nodes. This is because the relay node becomes an assigned orthogonal channel. This occurs in the polar coding sequence in the relay channel, where the relay node can transmit simultaneously on the same channel.

Accordingly, a search for a method for providing a relay network having high reliability and performance is required.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a communication method of a relay network including a source node, a first relay node, a second relay node and a destination node.

According to an embodiment of the present invention for achieving the above object, a communication method of a relay network including a source node, a first relay node, a second relay node and a destination node, the source node is the first relay node and the Broadcasting polarized information Orthogonal Frequency Division Multiplexing (OFDM) blocks to each of the second relay nodes; The first relay node processing the broadcast OFDM blocks; The second relay node processing the broadcast OFDM blocks; The first relay node transmitting the processed OFDM blocks to a destination node; And transmitting, by the second relay node, the processed OFDM blocks to a destination node.

The source node includes eight transmit antennas, each of the first relay node and the second relay node includes eight receive antennas and four transmit antennas, and the destination node includes eight receive antennas. It may also include.

In addition, the broadcasting step includes the steps of up-switching the eight consecutive OFDM blocks in a specific time slot; Down-switching the contiguous eight OFDM blocks in another specific time slot; And broadcasting the up-switched eight OFDM blocks and the down-switched eight OFDM blocks, respectively.

In the up-switching processing step, the up-switching process may be performed using the following up-switching matrix.

In the down switching process step, the down switching process may be performed using the following down switching matrix.

In the processing of the first relay node, the up-switched eight OFDM blocks may be processed according to the following equation.

In addition, in the processing of the second relay node, the eight down-switched OFDM blocks may be processed according to the following equation.

And decoding, by the destination node, the OFDM blocks received from the first relay node and the second relay node; And depolarizing the decoded OFDM blocks by the destination node.

In the decoding step, decoding may be performed using successive interference cancellation (SIC) decoding.

In addition, in the depolarizing step, depolarizing may be performed using the following equation.

According to various embodiments of the present disclosure, it is possible to provide a communication method of a relay network including a source node, a first relay node, a second relay node, and a destination node, so that the relay network has high reliability and high performance. It becomes possible.

1 illustrates an up-down relay network model according to an embodiment of the present invention;
2 illustrates an eight antenna polar switching up-down relay network system, in accordance with an embodiment of the present invention;
3 is a graph comparing a polar MIMO OFDM relay system with a conventional Li-Xiz-Lee ML decoding MIMO-OFDM system according to an embodiment of the present invention;
4 is a flowchart provided to explain a communication method of a relay network including a source node, a first relay node, a second relay node, and a destination node according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings.

I. Introduction

In this embodiment, a reliable 8x8 up-down switching polar relay code based on the 3GPP LTE standard is proposed. According to this embodiment, a polar encoder and an OFDM modulator are performed continuously on both the source node and the relay node, and time reversion and complex conjugation operations are performed at each relay node. It is performed separately, and the successive interference cancellation (SIC) decoder along with the cyclic prefix (CP) removal is performed at the destination node. According to the present embodiment, decoding in a relay without delay is not necessary, which has a low complexity. The numerical results show that a system coded by polar code performs better than a normal environment.

This embodiment aims to provide a simple design of the relay system so that a good symmetric capacity of the relay channel can be achieved based on polar coding with a reliable propagation decoder at the destination node.

II. Channel polarization according to the present embodiment: Up-Down polar relay system

A multiple input multiple output (MIMO) system in which a frequency reconfigurable antenna is applied to a transmitter and a receiver has good diversity gain and multiplexing gain. As the number of antennas increases, diversity gain and multiplexing gain increase proportionally.

1 is a diagram illustrating an up-down relay network model according to an embodiment of the present invention. The multiple antenna system in the up-down relay network model as shown in FIG. 1 has high diversity gain and multiplexing gain.

Hereinafter, as shown in FIG. 2, a distributed wireless communication system based on Orthogonal Frequency Division Multiplexing (OFDM) modulation having N sub-carriers is considered. 2 illustrates an eight antenna polar switching up-down relay network system, in accordance with an embodiment of the present invention.

As shown in FIGS. 1 and 2, the polar switching up-down relay network system 100 includes a source node 110, a first relay node 120, a second relay node 125, and a destination node 130. It includes.

Source node 110 broadcasts eight information OFDM blocks 112 to a relay node. The first relay node 120 processes the received OFDM block to generate a first information bit 121. The second relay node 125 processes the received OFDM block to generate a second information bit 126. In addition, the destination node 130 may SIC decode 132 OFDM blocks for the first information bit 121 and the second information bit 126 received from the first relay node 120 and the second relay node 125. And depolarizing to finally generate the eight information OFDM blocks 134 recited.

As shown in FIG. 2, the source node 110 includes eight transmit antennas, the first relay node 120 and the second relay node 120 include eight receive antennas and four transmit antennas. The destination node 130 will include eight receive antennas.

As shown in FIG. 2, such a network system includes one source node S, one destination node D, and two relay nodes R∈ {R ₁ , R ₂ }. The number of antennas of the source node S, the relay node R, and the destination node D are N _s , N _r , and N _d, respectively. Here, N _s OFDM symbols are transmitted with N _s = 2 ⁿ .

는 OFDM 심볼을 독립적으로 정확하게 처리할 수 있다고 가정한다. 소스 노드 S의 평균 전송 전력은 p_t이다. In the following, we consider the design of a polar relay structure that can mitigate relay synchronization errors. Each relay node

Assume that OFDM symbols can be independently and accurately processed. The average transmit power of source node S is p _t .

In this embodiment, it is assumed that N _s = N _r = N _d = 1. This assumption can be applied to any node including multiple antennas. The relay structure is assumed to be half-duplex. This indicates that the source node S and the relay node R cannot transmit and receive at the same time. N _s independent OFDM symbols are simultaneously transmitted from the source node S to the destination node D in two steps. The limit of total network power is p = p _t + 2p _r . In addition, a power allocation policy according to the following equation is applied.

로 표시하고, 릴레이 노드 R 및 목적지 노드 D 사이에서

로 표시된다. 여기에서, H와 K는 분포 CN(0,1)에 대해 i.i.d(Independently and Identically Distributed )인 것으로 가정한다. This channel model is used between source node S and relay node R.

, Between the relay node R and the destination node D

. Here, it is assumed that H and K are iid (Independently and Identically Distributed) for the distribution CN (0,1).

A source radio relay triple relay system is equivalent to a two part radio system. The polar channel model is as follows.

(1)

(One)

(2)

(2)

및

는 평균 0, 분산 1인 독립 복소수 가우시안 랜덤 변수(Gaussian random variable)이다. From here,

And

Is an independent complex Gaussian random variable with an average of 0 and a variance of 1.

Based on the MIMO relay channels H and K of equations (1) and (2), consider a polar system for the transmission of the signal vector x. Here, we consider a polar system for four timeslots (i.e., up-down polarized MIMO relay communication model in a turning switch).

The system has two phases. In phase 1, the source node broadcasts information OFDM symbols polarized from source node S to relay node R. In phase 2, the source node S stops transmitting, and each relay node R _k processes the received OFDM symbols and retransmits the processed OFDM symbols to the destination node.

III. Up-Down state switching polarizing cooperative relay system

로 표시한다. 또한, 계산의 편의를 위해 다음을 정의한다. At the source node S, the transmitted information is modulated with a complex symbol x _ij , after which N modulated symbols corresponding to one block are sent to the OFDM modulator of the N subcarriers. Four consecutive OFDM blocks

. Also, for convenience of calculation, the following is defined.

In the first time slot, eight consecutive OFDM blocks are processed at the source node S by an 8x8 matrix Q ₈ . That is, it is processed by the following equation.

는 사이즈 N×8의 편파화된 행렬을 나타내고,

는 8개의 OFDM 블록에 대응되는 사이즈 N×8의 신호 행렬을 나타내며,

이며, 다음과 같은 식이 만족된다. From here,

Represents a polarized matrix of size N × 8,

Denotes a signal matrix of size N × 8 corresponding to eight OFDM blocks,

And the following equation is satisfied.

In addition, the following formula represents an up switch.

And, as follows, the transpose of the above matrix represents the down switch.

In an OFDM modulator, eight consecutive blocks are modulated by an N-point fast Fourier transform (FFT). Thereafter, each block is precoded by a cyclic prefix (CP) of length l _cp . Thus, each OFDM symbol consists of samples of length L _s = N + l _cp .

이며, 이는 릴레이 노드 R₁을 거쳐갔을 때와 비교했을 때의 차이인 상대적 딜레이다. 주파수 선택 페이딩 채널과 타이밍 에러를 포함시키켜 고려하면,

가 된다. 8개의 연속된 OFDM 심볼은

로 표시한다. 여기에서,

는 FFT(u_i) 및 대응되는 순환전치(CP)로 구성된다. Finally, four OFDM symbols are broadcast to two relay nodes. The overall relative delay of the process from source node S to relay node R ₂ to destination node D is

This is the relative delay, which is the difference compared with when passing through the relay node R ₁ . Considering including the frequency selective fading channel and timing error,

. 8 consecutive OFDM symbols

. From here,

Is composed of FFT (u _i ) and the corresponding cyclic prefix (CP).

와

로 표시하며, 이들은 각각 릴레이 노드 R₁과 R₂에서 처리된 것을 나타낸다. At each relay R _k , the received noisy signal is simply processed and sent to the destination node D. It is assumed that the channel coefficient is a constant for eight OFDM symbol intervals. Two processed signal vectors

Wow

Denoted as processed at relay nodes R ₁ and R ₂ , respectively.

로 수신된 신호들은 다음과 같다. Thus, for eight consecutive OFDM symbol durations

The received signals are as follows.

는 소스 노드 S에서의 전송 전력이고,

는

로 정의되는 L×1 벡터이며, * 는 선형 컨볼루션(linear convolution)을 나타내고,

는 4개의 연속된 OFDM 심볼 기간에 대해 평균 0, 분산 1을 가진 릴레이 노드 Rk의 AWGN(additive white Gaussin noise)를 나타낸다.From here,

Is the transmit power at source node S,

The

Is an L × 1 vector, where * represents linear convolution,

Denotes the additive white Gaussin noise (AWGN) of the relay node Rk with an average of 0 and a variance of 1 for four consecutive OFDM symbol periods.

를 편파화하고, 신호처리하여, 목적지 노드로 전송한다. 신호 처리 연산이 수행된 후에, 각각의 릴레이 노드 R_k는 평균 전송 전력 p_r을 유지하는 동안, 전송한 심볼을 스칼라

로 증폭한다. 주파수 선택 페이딩 채널을 이용하기 위한 PF 스킴을 만들기 위해, 각각의 릴레이 노드 R_k는 수신된 OFDM 심볼에 대해 오직 시간 역전 연산(time reversal operation) 또는 켤레 복소수 연산(complex conjugation ooperation)을 수행한다. After that, each relay node R _k is a received noise mixed signal.

Is polarized, signal processed, and sent to the destination node. After the signal processing operation is performed, each relay node R _k scalar the transmitted symbols while maintaining the average transmit power p _r .

To amplify. To make a PF scheme for using the frequency selective fading channel, each relay node R _k performs only a time reversal operation or a complex conjugation ooperation on the received OFDM symbol.

At the destination node, the cyclic prefix CP removes each OFDM symbol. It should be noted that the relay node R ₁ has performed a time reversal operation of the noise mixed signal including the information symbol and the cyclic prefix (CP). Here, after the destination node removes the CP, the time reversal is performed only for the information symbols as follows.

Then, using the property of FFT / IFFT, the following definition can be obtained.

로써 N-포인트 벡터의 마지막

샘플 변화를 얻기 위하여 OFDM 시스템에서 순환전치(CP)를 제거하면, 목적지 노드에서 다음을 얻을 수 있게 된다. Definition 2.1: Given the OFDM symbol processed at relay node R ₁ , the N-point vector and the first

As the last of the N-point vectors

By removing the CP in the OFDM system to obtain the sample change, the following can be obtained at the destination node.

는

로 정의되는 N×1 벡터이고,

는 소스 노드 S로부터 릴레이 노드 R₁까지의 채널

의 최대 경로 딜레이를 나타내며, 즉,

를 나타낸다. 마찬가지 방법으로, 또 다른 N×1 벡터인

는

로 정의할 수 있다. From here,

The

Is an N × 1 vector defined by

Is the channel from the source node S to the relay node R ₁

Represents the maximum path delay of,

Indicates. In a similar way, another N × 1 vector

The

.

샘플 늦게 목적지 노드에 도착한다. l_cp는 충분히 길기 때문에, 서브캐리어들 사이의 직교성은 여전히 유지된다. 시간 도메인에서 딜레이

는 주파수 도메인에서의 위상 변화에 대응된다. 즉, 아래와 같다. Thereafter, the received OFDM symbol is converted by an N-point FFT. Due to a timing error, the OFDM symbol received from relay node R ₂ is greater than the symbol received from relay node R ₁ .

The sample arrives at the destination node late. Since l _cp is long enough, the orthogonality between the subcarriers is still maintained. Delay in the time domain

Corresponds to a phase change in the frequency domain. That is, it is as follows.

와

이다. From here,

Wow

to be.

샘플 변화는 위상 변화

에 대응되고, 따라서, 총 위상 변화는 이다. CP 제거 및 FFT 변환 후에 목적지 노드 D에서의 4개의 연속된 OFDM 블록들을 위한 수신된 신호는

로 나타낸다. 결론적으로, 다음을 얻을 수 있다. Similarly, in the time domain

Sample change is phase change

And thus, the total phase change is to be. The received signal for four consecutive OFDM blocks at destination node D after CP removal and FFT transform

Respectively. In conclusion, we can obtain:

A. For Up Polar Relays

In the case of the up-polar relay, it is possible to define a new mapping method in the relay node using a 2 × 2 up-polar code as follows.

,

를 만족한다. 따라서, 상기 수식 (16)은 각각의 서브캐리어 u,

에 대해 폴라 코드 형태로 다음과 같이 표현될 수 있다. According to the nature of the FFT transform for N × 1 point vector x,

,

. Thus, Equation (16) is based on each subcarrier u,

It can be expressed as follows in the form of polar code for.

, e₀ 및 e는 다음과 같이 주어진 편파화된 노이즈를 나타낸다. From here,

, e ₀ and e represent the polarized noise given by

,

는 x_i의

번째 원소이며,

는

의

번째 원소이고,

는

의 k번째 원소이며,

이다. From here,

,

Of x _i

Second element,

The

of

Second element,

The

Kth element of,

to be.

From equation (19), it can be easily seen that the channel coefficient can be changed with 8x8 polar coding. By obtaining such a signal, the destination node can be directly decoded using the SIC recursive decoding method.

B. For Down Polar Relays

In the previous up-polar relay section, we obtained an 8x8 polar signal at the destination node. To obtain an 8x8 down polar code, another mapping is specified by 2x2 down polar code. Therefore, the same method as the up polar relay is applied to the down polar relay. For down polar relays, you can define the following mappings:

에서 폴라 코드 형태로 다음과 같이 쓸 수 있다. Thus, equation (16) is used for each subcarrier

In polar code, you can write

This is expressed as follows.

이고, e₀ 및 e는 다음과 같이 주어지는 편파화된 노이즈를 나타낸다. From here,

And e ₀ and e represent polarized noise given by

이고,

는 x_i의

번째 원소이며,

는

의

번째 원소이고,

는

의 k번째 원소이며,

이다. From here,

ego,

Of x _i

Second element,

The

of

Second element,

The

Kth element of,

to be.

From Equations (19) and (23), the up and down 8 polar switching forms can be easily obtained, and the up-down switch analysis can be easily obtained.

IV. Decoding of Polar Relay System

Hereinafter, the SIC (Successive Interference Cancellation) decoding for a polar MIMO relay system to which a standard complex constellation such as Binary Phase Shift Keying (BPSK) modulation constellation is applied is considered.

의

번째 서브캐리어의 각각의 신호

는 R_k로 독립적으로 전송된다. 그리고, 채널 출력

은 트랜지션 확률

을 얻게 된다. 8개의 OFDM 심볼 내의 각각의 서브 캐리어에 대해, 업-다운 편파화 시스템에 대해 간단화된 노테이션(notation)

,

을 이용한다. 여기에서,

및

이다. OFDM block

of

Signal of the first subcarrier

Is independently transmitted as R _k . And channel output

Is the transition probability

. Simplified notation for up-down polarization system, for each subcarrier within eight OFDM symbols

,

. From here,

And

to be.

를 가진다. 여기에서,

이다. 무선 네트워크의 신뢰성 측정방법으로써, 채널 파라미터인 대칭 용량(symmetric capacity) I(W)는 약간의 변조가 이용될 수 있다. I(W)를 동일한 확률을 가진 입력을 이용하여 얻을 수 있는 신뢰할 수 있는 통신이 가능한 가장 높은 비율을 나타낸다. Considering the source node S of the transmission antenna and the relay node R _k receive antennas each pair of relay channel H and the relay node R _k channel K to the destination node D from the from of which mean 0, dispersion 1, an independent complex Gaussian random Variable. Each single link channel W is transition probability

. From here,

to be. As a reliability measurement method of a wireless network, some modulation may be used for the channel parameter symmetric capacity I (W). I (W) represents the highest rate of reliable communication that can be achieved using inputs with equal probability.

를 생성한다. 소스 원소

에 대한 각각의 원소

인 4개의 결정 원소로 구성된 디코더를 시각화 할 수도 있다. The Successive Iterative Cancellation (SIC) decoder of the down polarization system is estimated from y to x.

. Source elements

Each element for

It is also possible to visualize a decoder consisting of four crystal elements.

와 함께 시작된다. 그 후, 이전의 모든 결정 원소

이 수신될 때까지 기다린다. 그리고, 이들이 모두 수신되면, LR(Likaelihood Ratio)

가 아래와 같이 계산된다. The depolarizing algorithm of the polar relay system is the i-th decision element for the down polarization system.

Begins with. After that, all previous crystal elements

Wait until is received. And when they are all received, LR (Likaelihood Ratio)

Is calculated as follows.

And a crystal element is calculated as follows.

가 전송된다. 디코딩 알고리즘의 복잡도는 LF의 계산의 복잡도에 의해 결정되며, 이는

이다. After that, the subsequent crystal element

Is transmitted. The complexity of the decoding algorithm is determined by the complexity of the calculation of the LF, which

to be.

On the other hand, for the up-polarization system the low level of LR is given by

Also, the high level of LR is calculated as follows.

및

는 LR

및

과 같은 짝으로 구성된다. 반면, MIMO 릴레이 채널의 대칭적인 성질 때문에, 다른 두 LR인

및

는

및

로부터 구성된다. 또한, 두 다운 레벨 LR인

및

는 가장 낮은 레벨(최초 레벨) LR인

및

로부터 구성된다. 여기에서,

이다. 이와 같은 처리는 LR의 총 개수의 정확한 카운트를 위한 방법이다. As such, the LR of the polar MIMO OFDM relay system for the two polar systems can be calculated. The advantage of this depolarizing algorithm is the relationship of two levels LR in the coordinate system. For example, two LR

And

LR

And

Consists of pairs such as On the other hand, due to the symmetrical nature of the MIMO relay channel, the other two LRs

And

The

And

It is constructed from. Also, two downlevel LRs

And

Is the lowest level (initial level) LR

And

It is constructed from. From here,

to be. This process is a method for accurate counting of the total number of LRs.

를 위한 LR에 대응되는 12개의 노드가 있다. Next, an SC decoder for switching the polar MIMO-OFDM relay system will be described. Determinant

There are 12 nodes corresponding to LR for.

및

를 생성할 필요는 없게 된다. 마찬가지로, 업 편파화 채널에서 전송되는 동안 낮은 신뢰도를 가진 프로즌 비트(frozen bit)가 되기 때문에, 업 편파화 시스템에서,

및

는 생성될 필요가 없게 된다. 이와 같은 이유에서, 본 실시예에 따른 디폴라라이징 알고리즘은 다운 편파화 시스템에서

으로 직접 세팅되고, 업 편파화 시스템에서

로 세팅되게 된다. 이와 같은 디코딩 처리는 모든 정보 비트 x가 끝까지 디코딩 될 때까지 계속된다. In down polarization systems, because it becomes a frozen bit with low reliability during transmission on the down polarization channel,

And

You do not need to create a. Likewise, in an up-polarized system, since it becomes a frozen bit with low reliability while being transmitted on an up-polarized channel,

And

Does not need to be created. For this reason, the depolarizing algorithm according to the present embodiment is applied in the down polarization system.

Can be set directly in the

Will be set to. This decoding process continues until all information bits x are decoded to the end.

로부터 x를 얻을 수 있게 된다. Next, it can be seen that the polar MIMO OFDM relay system has BER performance as a result of the simulation. Thus, in a polar MIMO OFDM relay system with high reliability

You can get x from.

3 is a graph comparing a polar MIMO OFDM relay system with a conventional Li-Xiz-Lee ML decoding MIMO-OFDM system according to an embodiment of the present invention. As shown in FIG. 3, a 1 dB coding gain can be obtained in 8 antenna up-down polar coding. In addition, according to the present embodiment, the relay node does not need decoding. Each relay node performs only a simple encoding operation, which makes transmission very simple. Accordingly, the bottleneck in the data rate can be reduced. In addition, according to the present embodiment, the complexity of the polar MIMO OFDM relay system is low.

V. Flowchart description of relay network

4 is a flowchart provided to explain a communication method of a relay network including a source node, a first relay node, a second relay node, and a destination node according to an embodiment of the present invention. The description of FIG. 4 will be described with reference to the configuration diagrams of FIGS. 1 and 2.

First, the source node 110 broadcasts information orthogonal frequency division multiplexing (OFDM) blocks polarized to each of the first relay node 120 and the second relay node 125 (S410).

Specifically, the source node 110 up-switches eight consecutive OFDM blocks in a particular time slot. The source node 110 down-switches the consecutive eight OFDM blocks in another specific time slot. Thereafter, the source node 110 broadcasts eight up-switched OFDM blocks and eight down-switched OFDM blocks, respectively. At this time, the source node 110 performs the up-switching process by using the up-switching matrix described above and performs the down-switching process by using the down-switching matrix described above. This up / down switching process corresponds to the polarizing or polarizing process.

Thereafter, the first relay node 120 processes the broadcast OFDM blocks (S420). Specifically, the first relay node 120 processes eight OFDM blocks that are up switched according to Equation (19).

The second relay node 125 processes the broadcast OFDM blocks (S430). Specifically, the second relay node 125 processes eight OFDM blocks that are down switched according to Equation (23) described above.

Next, the first relay node 120 transmits the processed OFDM blocks to the destination node 130 (S440). In operation S450, the second relay node 125 transmits the processed OFDM blocks to the destination node 130.

Thereafter, the destination node 130 decodes the OFDM blocks received from the first relay node 120 and the second relay node 125 (S460). In detail, the destination node 130 performs decoding using Successive Interference Cancellation (SIC) decoding 132.

In operation S470, the destination node 130 depolarizes the decoded OFDM blocks. In detail, the destination node 130 performs depolarizing by using the above-described equation (28).

Through this process, the relay network 100 performs communication, and has high reliability and performance.

On the other hand, the technical idea of the present invention can be applied to a computer-readable recording medium containing a computer program for performing the communication method of the relay network 100 according to the present embodiment. In addition, the technical idea according to various embodiments of the present invention may be embodied in computer-readable code form recorded on a computer-readable recording medium. The computer-readable recording medium is any data storage device that can be read by a computer and can store data. For example, the computer-readable recording medium may be a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical disk, a hard disk drive, or the like. In addition, the computer readable code or program stored in the computer readable recording medium may be transmitted through a network connected between the computers.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention.

100: relay network 110: source node
120: first relay node 125: second relay node
130: destination node

Claims (10)

In a communication method of a relay network comprising a source node, a first relay node, a second relay node and a destination node,
A source node broadcasting information orthogonal frequency division multiplexing (OFDM) blocks polarized to each of the first relay node and the second relay node;
The first relay node processing the broadcast OFDM blocks;
The second relay node processing the broadcast OFDM blocks;
The first relay node transmitting the processed OFDM blocks to a destination node; And
Transmitting, by the second relay node, the processed OFDM blocks to a destination node. The method of claim 1,
The source node comprising:
8 transmit antennas,
Each of the first relay node and the second relay node,
8 receive antennas and 4 transmit antennas,
The destination node,
Relay network communication method comprising the eight receiving antennas. The method of claim 2,
The broadcast step,
Up-switching the eight consecutive OFDM blocks in a particular time slot; And
Down switching the eight consecutive OFDM blocks in another particular time slot; And
And broadcasting the up-switched eight OFDM blocks and the down-switched eight OFDM blocks, respectively. The method of claim 3,
The up-switching processing step,
The relay network communication method according to the following up switching matrix to perform the up switching process.

The method of claim 3,
The down switching process step,
The relay network communication method, characterized in that to perform the down switching process using the down switching matrix.

5. The method of claim 4,
The processing step of the first relay node,
And relaying the up-switched eight OFDM blocks according to the following equation.

5. The method of claim 4,
The processing step of the second relay node,
And processing the down-switched eight OFDM blocks according to the following equation.

5. The method of claim 4,
The destination node decoding the OFDM blocks received from the first relay node and the second relay node; And
And depolarizing the decoded OFDM blocks by the destination node. 9. The method of claim 8,
The decoding step,
A method for relay network processing, wherein decoding is performed using Successive Interference Cancellation (SIC) decoding. 9. The method of claim 8,
The depolarizing step,
Relay network processing method characterized in that the depolarizing is performed using the following formula.

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