KR100672090B1 - HSM Detection Method of MG V-blast System - Google Patents

Abstract

The present invention provides a MIMO V- using a group partitioned symbol cancellation detection algorithm to improve the performance of a V-BLAST (Vertical-BLAST) reception algorithm for a next generation Multi Input Multi Output (MIMO) communication system. A method for detecting HSC in a BLAST system. The present invention provides a method comprising the steps of: detecting layers divided into a plurality of groups, each group having a different number of layers; Measuring interference of the transmitted signals in each group, except for the interference signal measured in the group from the received signal, and remaining signals used in the parallel detection technique in the following group; Repeating the parallel measurement and removal procedure from step to last group. In addition, multiple steps following PSC detection are used in the HSC detection technique. The present invention is a hybrid symbol cancellation (HSC) method that combines the advantages of the system delay and BER performance of the existing SCC and PSC schemes, and considers the trade-off between system delay and detection complexity. Flexibility and good performance.

Multi Input Multi Output (MIMO), SCC, PSC, V-BLAST, HSC, Signal, Interference

Description

Hybrid Symbol Cancellation Detecting Method of Multi-input Multi-output V-BLAST System

1 is a block diagram showing a conventional general V-BLAST system.

Figure 2 is a control block diagram showing a HSC detection method of the MIMO V-BLAST system according to the present invention.

3 is a table comparing various detection algorithms.

<Description of the symbols for the main parts of the drawings>

10: transmitter

11: vector encoder

20: receiver

21: V-BLAST Decoder

30: unit group

The present invention provides a MIMO V-BLAST system of a group partitioned symbol cancellation detection algorithm for improving the performance of a V-BLAST (Vertical-BLAST) receiving algorithm of a next-generation MIMO communication system. It relates to a HSC detection method of.

MIMO (Multi-input Multi-output) communication system is being introduced for next generation mobile communication for high speed data transmission. MIMO communication system is able to support faster transmission speed and larger capacity than conventional communication system because it can obtain coding gain by using diversity gain and space-time processing technology through communication using multiple transmit antennas and multiple receive antennas. Can be.

As an existing reception algorithm, V-BLAST (Vertical-Bell Laboratory Space-Time) has been proposed. The V-BLAST reception algorithm inevitably delays the system as the number of antennas increases to see a good BER characteristic. On the contrary, preventing the system delay increases the BER characteristic and increases the system complexity.

1 shows the structure of a typical MIMO V-BLAST system.

One data permutation is divided into M partial permutations, and each partial permutation is encoded into a symbol and transmitted on a channel. In the 1 to M transmit antennas having synchronized symbol times, symbol rates (1 / T symbols / sec) operate in the same channel (co-channel).

Each transmitter 10 applies a quadrature amplitude modulation (QAM) technique with the same constraint. Here each sub-permutation has the same constraint and consists of L symbols. Since each transmit antenna has a power of 1 / M, it is assumed that the total transmit power is kept constant and the antennas are independent of each other.

로 표현할 수 있다. 여기서 N, M은 각각 수신안테나 수와 송신안테나 수를 나타낸다. 그리고

는

번째 송신 안테나와

번째 수신안테나의 복소 전달함수를 나타내고, 수신신호의 검출을 위해 수신안테나 수는 송신안테나 수보다 항상 같거나 많아야 한다(

). 1 to N reception antennas use a general QAM receiver 20. The receivers 20 also assume the same channel and each of the receivers 20 receives a signal from all M transmit antennas. Assuming a flat channel, the channel transfer function

Can be expressed as Where N and M represent the number of reception antennas and the number of transmission antennas, respectively. And

Is

With the first transmit antenna

Represents the complex transfer function of the first receiving antenna, and for detecting the received signal, the number of receiving antennas should always be equal to or greater than the number of transmitting antennas.

).

It is assumed that channel time-varying is quasi-static for L symbols, and channel estimation is done perfectly.

As a conventional reception algorithm, V-BLAST (Vertical-Bell Laboratory Space-Time) has been proposed. V-BLAST reception algorithms include successive symbol cancellation (SSC) and parallel symbol cancellation (PCS). However, the SSC detection technique can obtain a BER (Bit Error Ratio) characteristic to detect a signal having a high reception power, that is, a channel characteristic first, through power reordering between detection layers, but the number of antennas increases. Delay is inevitably created. In addition, the PSC detection technique does not use power reordering, thereby preventing system delay, but having a poor BER characteristic and increasing system complexity.

Accordingly, the present invention has been made to solve the above-described problems, and in order to improve the performance of the V-BLAST reception algorithm, the system delay of the conventional SSC (parallel symbol cancellation) and PSC (parallel symbol cancellation) techniques A hybrid method that improves BER performance is provided as a hybrid symbol cancellation (HSC) detection method of the MIMO V-BLAST system. Each detection layer is divided into a number of groups, and in each group, the PSC detector method and the SSC are applied between groups. The present invention aims to build a better system by selecting a case in which the developer of the system is flexible and has good performance by considering a trade-off between system delay and detection complexity.

HSC detection method of the MIMO V-BLAST system according to the present invention for achieving the above object, in the MIMO V-BLAST system, the detection layers are divided into a number of groups, each group has a different number of layers step; Measuring interference of the transmitted signals in each group, except for the interference signal measured in the group from the received signal, and remaining signals used in the parallel detection technique in the following group; Interference of the signals transmitted in each group is measured, and the interference signals measured in the group are excluded from the received signal, and the remaining signals are used in the parallel detection technique in the following group. Repeatedly carried out to; characterized in that it comprises a.

In addition, it is preferable that multiple steps according to PSC detection be used in the HSC detection technique.

In the hybrid symbol cancellation (HSC) detection scheme proposed by the present invention, the detection layers are divided into several groups. Each group has a different number of layers. Within each group, parallel detection measures the interference of the transmitted signal. The interference signal measured in the group is subtracted from the received signal and the remaining signals are used in the parallel detection technique in the following group. This parallel measurement and successive cancellation procedure is repeated to the last group in the stage. Multiple steps according to PSC detection are used in the HSC detection technique.

2 shows the HSC detection process proposed in this study.

The detection process for one transmitted vector symbol is performed in discrete baseband and assumes that symbol synchronization is perfect at the receiver 20.

는 송신 심벌 벡터를 나타내고, 수신된 신호

Denotes a transmit symbol vector, and the received signal

(1)

(One)

to be.

인 넓은 의미에서 독립 분포 정상 상태[i.i.d(identical independent distribution) wide-sense stationary]이다.Where v is the variance

In a broad sense, it is an independent independent distribution (iid) wide-sense stationary.

단계를 갖는 HSC 검출 구조를 나타내고 있다. 각 단계는 간섭 측정과 제거(cancellation) 단위의 G 그룹(30)으로 구성되어 있다.In FIG. 2, M detection layers, G group 30,

The HSC detection structure with steps is shown. Each step consists of a G group 30 of interference measurements and cancellation units.

을 사용하고,

의 순열은 HSC 검출을 수행하기 위해 사용되어진다. 각 그룹(31,32)에서

개의 레이어가 있다고 하면, 첫 번째 그룹(31) 널링(nulling)은 각각 수신된 신호에서 모든 레이어에 대해 수행한다. 그 결과 값은 첫 번째 그룹(31)에서 간섭을 추정하기 위해 사용되어 진다. 추정된 간섭성분은 수신된 신호로부터 빼고 나머지 결과 값은 두 번째 그룹(32)의 입력 신호로 사용되어진다. 예를 들면, 첫 번째 단계에서, g-번째와 (g+1)-번째 그룹이 만들어 졌다고 하면 아래와 같이 나타낼 수 있다.Looking at the HSC procedure, as in the SSC detection scheme, the descending set according to the magnitude of the received signal

Using,

The permutation of is used to perform HSC detection. In each group (31,32)

If there are two layers, nulling of the first group 31 is performed for all layers in the received signal, respectively. The resulting value is used to estimate the interference in the first group 31. The estimated interference component is subtracted from the received signal and the remaining result is used as the input signal of the second group 32. For example, in the first step, say that the g-th and (g + 1) -th groups have been created,

는 추정된 간섭신호,

는 간섭을 뺀 나머지 신호,

는

의

번째 칼럼(column),

는 결정 통계치(static),

는

의 zeroing 칼럼(colunm)

에서 구해지는 채널 매트릭스(matrix)이다.here,

Is the estimated interference signal,

Is the signal minus the interference,

Is

of

Column,

Is a decision statistic (static),

Is

Zeroing column

This is the channel matrix obtained from.

이라고 하면, 본 발명에서 제안하는 2-그룹 HSC 검출기법은 각 그룹이 2/M개의 레이어를 갖게 되고, 전체 시스템 지연은 단지 1이 된다. 그리고 PSC 검출 기법의 전체 복잡성은

이지만, HSC 검출 기법의 복잡성은

이 된다. By using the HSC technique, the detection delay is greatly reduced compared to the SSC technique, and the complexity is also reduced compared to the PSC technique. For example, the overall system delay of SSC detection

In this case, in the two-group HSC detection method proposed in the present invention, each group has 2 / M layers, and the total system delay is only one. And the overall complexity of the PSC detection technique

However, the complexity of the HSC detection technique

Becomes

Although the above has been illustrated and described with respect to preferred embodiments of the present invention, the present invention is not limited to the above-described embodiments, and the general knowledge in the field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Anyone with a variety of variations will be possible.

As described above, according to the HSC detection method of the MIMO V-BLAST system according to the present invention, the reception algorithm is proposed in the MIMO system based on the V-BLAST technique. In a combined manner, the system complexity is less than the PSC, and the system delay is less than the SSC. This represents the trade-off between complexity and delay. Therefore, the proposed system has the advantage of implementing a more flexible system according to the user's needs.

Claims (2)

In the MIMO V-BLAST system, The detection layers are divided into a plurality of groups, each group having a different number of layers; Measuring interference of the transmitted signals in each group, except for the interference signal measured in the group from the received signal, and remaining signals used in the parallel detection technique in the following group; Interference of the signals transmitted in each group is measured, and the interference signals measured in the group are excluded from the received signal, and the remaining signals are used in the parallel detection technique in the following group. Repeatedly performing until; HSC detection method of the MIMO V-BLAST system comprising a. The method of claim 1, The HSC detection method is a hybrid symbol cancellation (HSC) detection method of a MIMO V-BLAST system, characterized in that PSC detection is used in multiple stages.

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