CN1716812A - Receiver of multiple input and multiple output system - Google Patents

Abstract

The present invention discloses a kind of receiver with multi-incoming and multi-outgoing system, comprising a blocked and vertically-layered space time detecting unit for receiving signal vectors, among which the pending symbols for detecting will be divided into many groups and after completing the blocked and vertically-layered space time detection, the revised vectors of the received signals for all symbols will be sent out to a parallel and vertical layered space time detecting unit ; the detecting unit is used for receiving the vectors of the received signals for all symbols revised by the detecting unit; after completing the parallel and vertical layered space time detection of the revised vectors of the received signals for all symbols, the estimation of every symbol will be sent out. The invented device has greatly enhanced the demodulation under the little decrease or increase of the time delay.

Description

A kind of receiver of multi-input multi-output system

Technical field

The present invention relates to wireless communication technology field, be meant the receiver of a kind of multiple-input and multiple-output (MIMO, Multiple Input Multiple Output) system especially.

Background technology

The MIMO technology is the major technological breakthrough of wireless communication field, and it can improve the capability of communication system and the availability of frequency spectrum exponentially under the situation that does not increase bandwidth.The MIMO technology adopts many antennas (aerial array) to send simultaneously and received signal at transmitting terminal and receiving terminal.Because the signal that each transmitting antenna sends simultaneously takies same frequency band, thereby communication bandwidth does not increase.There is a space channel between each transmitting antenna and each reception antenna.If the channel impulse response of each space channel is independent, then mimo system can be created a plurality of parallel independently space channels by a plurality of transmitting antennas and a plurality of reception antenna between transmitting terminal and receiving terminal.Transmit information independently by these parallel space channels, the transmission data rate of mimo system must be multiplied.G.J.Foschini in 1998 and M.J.Gans have fully proved above-mentioned conclusion, and quantitatively point out: suppose that mimo system has M root transmitting antenna and N root reception antenna, under the arrowband slow fading channel, just can set up N * M rank channel matrix.This entry of a matrix element is independent identically distributed multiple Gaussian random variable.The channel capacity that mimo system can obtain will be that (m, n) doubly, wherein (m, n) minimum value among m and the n is got in expression to min, and total transmitting power remains unchanged for the min of the single output of single input (SISO, Single Input Single Output) system.

G.J.Foshini in 1996 had once proposed D-BLAST Bell Laboratory diagonal angle layered space-time architecture (the Diagonal D-BLAST of mimo system, BLAST:Diagonal Bell LaboratoriesLayered Space-time Architecture) method, this method can realize the demodulation of mimo system, and can obtain the capacity near theoretical capacity 90%.But D-BLAST method complexity is bigger, is difficult for real-time implementation.

1999, G.D.Golden, G.J.Foshini, R.A.Valenzuela and P.W.Wolniansky proposed a kind of BLAST method of simplification--structure during the Bell Laboratory vertical layered space (V-BLAST, Vertical BLAST).This method is in the laboratory real-time implementation.Experimental result shows: transmitting terminal and receiving terminal adopt the mimo system of 8 antennas and 12 antennas respectively under indoor environment, when changing in the scope of average SNR at 24dB～34dB, can obtain the spectrum efficiency of 20-40bps/Hz.Although this spectrum efficiency is to obtain under indoor environment, the spectrum efficiency of this magnitude is unprecedented.

In the V-BLAST method, suppose that M is a number of transmit antennas, correspondingly receiver adopts N root antenna to receive, and the symbolic vector that is sent out is: a=[a ₁, a ₂..., a _M] ^T, the received signal vector is:

r ₁＝Ha+v (1)

Here, H is that N * M ties up channel matrix, and v represents N dimension noise vector, and its component is independent identically distributed white Gaussian noise, σ ²Be the power of each noise component(s) in the received signal vector, σ _s ²Be the power that sends symbol, r ₁Be N dimension received signal vector.

S ≡ [k ₁, k ₂..., k _M] ^TBe integer 1,2 ..., the arrangement of M, this arranges the detected order of sign component among the expression symbolic vector a.The V-BLAST detection algorithm is by r ₁According to s ≡ [k ₁, k ₂..., k _M] ^TGiven order computation decision-making statistic y _K1, y _K2, y _KMBy decision-making statistic y _K1, y _K2, y _KMCan form the estimation of data symbol _K1, _K2..., _KM

Can calculate s ≡ [k according to certain optiaml ciriterion ₁, k ₂..., k _M] ^T, will be designated as S according to the optimal alignment that certain optiaml ciriterion calculates here _OPT≡ [k ₁, k ₂..., k _M] ^TBe set forth in given s ≡ [k below ₁, k ₂..., k _M] ^TThe testing process of following V-BLAST algorithm.

The V-BLAST algorithm adopts linear ZF and symbol to offset method, calculates the decision-making statistic serially.

Step is as follows:

Step 1: adopt N dimension ZF weight vector w _K1, by calculating r ₁The linearity of component merges, and statistic y obtains making a strategic decision _K1:

${\mathrm{<figure-callout\; id="1"\; label="y\; k"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">y</figure-callout>}}_{k_{}}=w_{k_1}^T{r}_1---\left(2\right)$

Step 2: by y _K1Quantize to obtain _K1:

${\hat{a}}_{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}=Q\left(y_{k_1}\right)---\left(3\right)$

Wherein, Q () is a quantization function, and this function is corresponding with the transmitting terminal modulator approach.A=[a ₁, a ₂..., a _M] ^TIn each symbol be that information bit obtains through ovennodulation.Step 3: suppose ${\hat{a}}_{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}=a_{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">k</figure-callout>}}_1}$ , from received signal vector r ₁The middle a that eliminates _K1, the received signal vector r that obtains revising ₂:

$r_2=r_1-{\hat{a}}_{k_1}{\left(H\right)}_{k_1}---\left(4\right)$

Here (H) _K1The k of representing matrix H ₁Row.

Received signal vector r according to 1～3 pair of correction of above-mentioned steps ₂Carry out same calculating, that is: by w _K2Obtain y _K2, again by y _K2Obtain a _K2Estimation _K2And r ₃K in order ₃, k ₄..., k _MCalculating is gone down, and can obtain the estimation that other are sent out symbol _K3, _K4..., _KM

Weight vector w _K1, w _K2..., w _KMCalculating be the key of algorithm.The concrete computational methods of weight vector are relevant with the calculation criterion that is adopted.Usually adopt ZF criterion and MMSE criterion to carry out the calculating of weight vector.Adopting under the ZF criterion vector w _K1, w _K2..., w _KMBe called as the ZF weight vector, satisfy following relation:

$w_{k_i}^T{\left(H\right)}_{k_j}=\left\{\begin{array}{c}0,j>i\\ 1,j=i\end{array}\right.---\left(5\right)$

Therefore, adopting under the ZF criterion, the V-BLAST algorithm can be realized by following recursive procedure:

Initialization:

G ₁＝H ⁺ (6a)

i＝1 (6b)

Carry out following calculating:

$k_i=\arg \underset{j\&NotElement;\{{\mathrm{<figure-callout\; id="1"\; label="k"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">k</figure-callout>}}_1,k_2,\&CenterDot;\&CenterDot;\&CenterDot;,k_{i-1}\}}{\min }{\left|\right|{\left(G_i\right)}_j\left|\right|}^2---\left(6c\right)$

$w_{k_i}={\left(G_i\right)}_{k_i}^T---\left(6d\right)$

$y_{k_i}=w_{k_i}^T{r}_i---\left(6e\right)$

${\hat{a}}_{k_i}=Q\left(y_{k_i}\right)---\left(6f\right)$

$r_{i+1}=r_i-{\hat{a}}_{k_i}{\left(H\right)}_{k_i}---\left(6g\right)$

$G_{i+1}=-H_{\stackrel{\&OverBar;}{k_i}}^{+}--\left(6H\right)$

i＝i+1 (6i)

Recursive calculation formula (6c)～(6i) just stops to calculate when i=M+1.At this moment obtained all and be sent out the estimation of symbol: by the V-BLAST method _K1, _K2..., _KM

In the above-mentioned formula ,+expression Moore-Penrose pseudoinverse; K among the order matrix H ₁, k ₂..., k _iClassify 0 column vector as, other column vectors remain unchanged, and just obtain matrix (G _i) _KiRepresenting matrix G _iThe 7th k _iOK.

In the Recursive Implementation of above-mentioned V-BLAST method, formula (6a) and (6h) be the computing formula of ZF criterion tenesmus zero vector.If adopt the MMSE criterion to calculate weight vector, formula (6a) and (6h) need change accordingly.No matter adopt which kind of criterion to calculate weight vector, the Recursive Implementation process of V-BLAST method all as mentioned above, the computing formula (6a) and the expression formula (6h) that are weight vector under the different criterions will be carried out corresponding conversion, are consistent with the criterion that is adopted.

Can see from the Recursive Implementation of above-mentioned V-BLAST method: the V-BLAST method adopts the thought of successive interference cancellation.That is: detect a symbol and just carry out interference cancellation one time; By interference cancellation to received signal vector once revise, make the received signal vector of correction no longer comprise the information of symbol after testing; The detection of all the other symbols is based on the received signal vector of revising, thereby eliminated the influence to other symbol detection of the symbol that detected, improves the detection performance of all the other symbols.

In the Recursive Implementation of above-mentioned V-BLAST method, formula (6c) is to calculate s according to the SNR maximal criterion _OPT≡ [k ₁, k ₂..., k _M] ^TFormula.Adopt this formula to show: after the estimation of the symbol of the calculating SNR of V-BLAST algorithm elder generation maximum, from the received signal vector, eliminate of the influence of this symbol to other symbol detection, from the received signal vector of revising, carry out the detection of SNR maximum symbol again, and then eliminate of the influence of this symbol all the other symbol detection.So analogize, the symbol of SNR minimum detects at last.It is maximum that this detection makes the symbol detection of SNR minimum be benefited in proper order, thereby make the best performance of whole successive interference cancellation method.

From above-mentioned analysis as can be known, existing receiver adopts the V-BLAST method, and its complexity adopts the D-BLAST method to reduce, but adopts the V-BLAST method also to have weak point:

Existing receiver adopts successive interference cancellation, and processing delay is bigger.Usually all need receiving terminal feeding back ACK/nack message in the MIMO communication, determine whether to carry out symbol by ACK/NACK information and retransmit.Therefore, the processing delay of receiver is more little, and the time delay of ACK/NACK feedback is just more little, and correspondingly the capacity of system and throughput are just big more.So the serial of V-BLAST offsets mode to be needed to improve.

Summary of the invention

In view of this, the object of the present invention is to provide a kind of receiver, make its processing delay that can effectively reduce the V-BLAST method, improve the symbol detection performance simultaneously.

In order to achieve the above object, the invention provides a kind of receiver of multi-input multi-output system, this receiver comprises:

Detecting unit (101) during the grouping vertical layered space, be used for the received signal vector, symbol to be detected in all received signal vectors is divided into some groups, finish grouping and detect during vertical layered space, the received signal vector of correction of exporting all symbols detecting unit (102) during to parallel vertical layered space;

Detecting unit (102) when walking abreast vertical layered space, the received signal vector of all symbols that detecting unit (101) is revised when being used for receiving through the grouping vertical layered space, after detecting when walking abreast vertical layered space by the received signal vector of the correction of all symbols, the estimation of exporting each symbol.

Detecting unit (101) comprising during described grouping vertical layered space: symbol packets with reset unit (201), the group internal symbol with last correction detects and interference cancellation unit (202) and pretreatment unit (203), wherein,

Symbol packets and rearrangement unit (201), be used for the received signal vector, with all symbol packets to be detected of received signal vector, will send symbolic vector and channel matrix is reset, and the group internal symbol that the received signal vector exports first correction to is detected and interference cancellation unit (202);

The group internal symbol of each correction detects and interference cancellation unit (202), detect group internal symbol corresponding in the received signal vector of importing, obtaining the estimated value of all symbols in this group and the signal of all symbols estimates, and detected all symbols are carried out interference cancellation, the received signal vector that obtains revising is as the group internal symbol detection of next one correction and the received signal vector to be detected/pending received signal vector of interference cancellation unit/pretreatment unit (203), and the signal of all symbols estimates to deliver to pretreatment unit (203) in the group;

Pretreatment unit (203), the group internal symbol that receives all corrections detects to be estimated with the signal of all symbols of interference cancellation unit (202) and the group internal symbol of last correction detects received signal vector with the correction of interference cancellation unit, obtain the received signal vector of the correction of all symbols, the received signal vector of the correction of described symbol estimates that with the received signal vector of the correction of interference cancellation unit and the signal of this symbol sum constitutes by the group internal symbol detection of last correction.

The group internal symbol of described correction detects with interference cancellation unit (202) and can comprise:

Weight vector computing unit (301) is used for calculating one with last weight vector according to the estimation of channel matrix, and exports each weight vector to corresponding decision-making statistic computing unit (302);

One is used for the received signal vector with last decision-making statistic computing unit (302), and determines the decision-making statistic according to the weight vector that receives, and exports it to transmission sign estimation unit (303);

One with last transmission sign estimation unit (303), estimate to send symbol according to the decision-making statistic that receives, and the estimated value that will send symbol exports signal to and estimates and interference cancellation unit (304);

Signal is estimated and interference cancellation unit (304), all send the estimated value of symbol in received signal vector and the group, and estimate according to the signal that the estimated value that sends symbol obtains sending symbol, and vector carries out interference cancellation to received signal, obtain the received signal vector of a correction and export it to next group internal symbol detecting and interference cancellation unit/pretreatment unit (203), and the signal that will send symbol estimates to deliver to pretreatment unit (203), and the signal of described transmission symbol is estimated as the amassing of column vector that the estimated value row corresponding with this symbol in the corresponding channel estimate matrix of this symbol constitute.

Detecting unit (102) can comprise during described parallel vertical layered space:

Signal correction unit 401, be used to detect the received signal vector of the correction of all symbols, and calculate an above weight vector according to the received signal vector meter of the correction of the estimation of channel matrix and all symbols, calculate the decision-making statistic of corresponding symbol respectively according to each weight vector that calculates, calculate the estimated value of this symbol by the decision-making statistic of this symbol, vector carries out one-level parallel interference cancellation at least to received signal, and the received signal vector of the more than one correction that will obtain through interference cancellation is sent to detecting signal unit;

Detecting signal unit 402 reappraises value of symbol by the received signal vector of the more than one correction that receives.

Described signal correction unit can comprise:

At least one-level parallel interference cancellation unit is connected in series between every grade of parallel interference cancellation unit, and afterbody parallel interference cancellation unit links to each other with detecting signal unit,

Wherein, described parallel interference cancellation unit is used for the received signal vector, and calculates an above weight vector; Decision-making statistic according to each weight vector parallel computation symbol correspondence; Utilize each decision-making statistic to carry out the estimation of symbol, obtain more than one sign estimation value; And then described more than one sign estimation value and received signal vector carried out interference cancellation; The received signal vector of the more than one correction that will obtain through interference cancellation exports next stage parallel interference cancellation unit/detecting signal unit to.

Described parallel interference cancellation unit can comprise:

Weight vector computing unit (501) is used for calculating one with last weight vector according to the estimation of channel matrix, and exports it to each decision-making statistic computing unit (502);

One is used for the received signal vector with last decision-making statistic computing unit (502), and determines the decision-making statistic according to the weight vector that receives, and exports it to transmission sign estimation unit (503);

Estimate the transmission symbol with last transmission sign estimation unit (503) according to the decision-making statistic that receives, and export it to interference cancellation unit (504) for one;

Interference cancellation unit (504), received signal vector and all send the estimated value of symbol, and according to the estimated value that sends symbol to received signal vector carry out interference cancellation, obtain the received signal vector revised more than one and export it to next stage parallel interference cancellation unit/detecting signal unit.

Described detecting signal unit can comprise:

Weight vector computing unit (501) is used for calculating one with last weight vector according to the estimation of channel matrix, and exports it to each decision-making statistic computing unit (502);

One is used to receive the received signal vector of correction with last decision-making statistic computing unit (502), and determines the decision-making statistic according to each weight vector that weight vector computing unit (501) calculates, and exports it to transmission sign estimation unit (503);

Estimate to send symbol according to the decision-making statistic that receives with last transmission sign estimation unit (503), obtain sending more than one the estimated value of symbol for one.

Receiver of the present invention detects when vector divides into groups vertical layered space to received signal and detects when walking abreast vertical layered space, detect during by the grouping vertical layered space and not only can reduce processing delay greatly, and can provide the received signal vector of the correction of all symbols after detecting when dividing into groups sky, detect when carrying out the parallel vertical layered spaces of some levels by the received signal vector of the correction of all symbols again, just can improve the detection performance of all symbols greatly.Like this, as long as control the group number of grouping well and the progression that detects during parallel vertical layered space just not only can reduce processing delay, and improve the performance of symbol detection.Therefore, the receiver that the present invention proposes reduces or increases under the very little situation in time delay, and demodulation performance but can be greatly improved.

Description of drawings

Fig. 1 is for realizing the structural representation of apparatus of the present invention;

Fig. 2 is the structural representation of detecting unit when dividing into groups vertical layered space among the present invention;

Fig. 3 is that i the group internal symbol of revising shown in Figure 2 detects the structural representation with the interference cancellation unit;

Fig. 4 is the structural representation of detecting unit when walking abreast vertical layered space among the present invention;

Fig. 5 is the structural representation of i level PIC unit in the signal correction unit shown in Figure 4;

Fig. 6 is the structural representation of S level PIC unit in the detecting signal unit shown in Figure 4.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing.

Figure 1 shows that MIMO receiver structure schematic diagram of the present invention.As shown in Figure 1, receiver of the present invention comprises grouping detecting unit 102 when detecting unit 101 and parallel vertical layered space during vertical layered space.Wherein, detecting unit 101 received signal vectors during the grouping vertical layered space, symbol to be detected in all received signal vectors is divided into the Z group, detect when finishing the grouping vertical layered space, the received signal vector of correction of exporting all symbols detecting unit 102 during to parallel vertical layered space, the received signal vector of all symbols that detecting unit 101 was revised when detecting unit 102 received through the grouping vertical layered space when walking abreast vertical layered space, after detecting when it is walked abreast vertical layered space, the estimation of exporting each symbol.

Operation principle of the present invention is: detecting unit 101 is divided into the Z group with symbol to be detected in all received signal vectors during the grouping vertical layered space, in first group, walk abreast and carry out the detection of all symbols, obtaining the estimation of all symbols and the signal of all symbols estimates, and the interference of all symbols in from the received signal vector, eliminating first group, the received signal vector that obtains revising, this received signal vector is as first group of detection of being used for second group code for second group input signal, makes the detection of second group code not be subjected to the interference of first group code; With the received signal vector of first group of output as the received signal vector that adopts during each symbol detection in second group, walk abreast and carry out the detection of all symbols, the signal of the estimation of each symbol and all symbols is estimated in obtaining second group, and the interference of all symbols in from the received signal vector of first group of output, eliminating second group, the received signal vector of further being revised, this received signal vector are used for the detection of the 3rd group code as second group of input signal vector to the 3rd group.The rest may be inferred, carries out the detection of other follow-up each group codes.After the detection of finishing the Z group code, the signal that obtains every group code in the Z group is respectively estimated, and the received signal vector of revising through Z group, and then estimate and, obtain the received signal vector of the correction of all symbols through the received signal vector that the Z group is revised by the signal of every group code.At last, export the received signal vector of the correction of all symbols, with its parallel detecting unit 102 when giving parallel vertical layered space.

The received signal vector through correction of all symbols of detecting unit 101 outputs adopted the multistage parallel interference cancellation when detecting unit 102 received the grouping vertical layered spaces when walking abreast vertical layered space.When carrying out every grade of parallel interference cancellation processing, detect the received signal vector of all symbols, and calculate an above weight vector, estimate the estimated value of all symbols according to weight vector; Again the symbol that estimates is carried out interference cancellation, obtain the received signal vector of the correction of all symbols, and then carry out the estimation of symbol.Wherein, the received signal vector of the correction of m symbol is to get rid of m symbol, the interference of removing all the other M-1 symbol from the received signal vector obtains, wherein, M is the sum of symbol to be detected in the received signal vector, the received signal vector that adopts during m symbol detection during this signal phasor is handled as the next stage parallel interference cancellation; During in the end the one-level parallel interference cancellation was handled, M the received signal vector of revising that is provided by previous stage carried out the detection of M symbol simultaneously, estimates M symbol, and this M estimated value is exactly the testing result of multistage parallel interference cancellation structure.The received signal vector that detects in first order parallel interference cancellation is handled is the received signal vector of the correction of all symbols of detecting unit 101 when empty from grouping, during other grades parallel interference was handled, the received signal vector was all through obtaining behind the upper level parallel interference cancellation.

Referring to shown in Figure 2, detecting unit 101 comprises during the grouping vertical layered space: symbol packets detects and interference cancellation unit 202 and pretreatment unit 203 with a group internal symbol of resetting unit 201, a Z correction.Wherein, symbol packets is divided into Z group with M to be detected in a received signal vector symbol according to certain criterion with rearrangement unit 201, and according to order of packets and group internal symbol order M symbol rearranged, correspondingly form the column vector of channel matrix and also reset the new channel matrix of formation; Z the group internal symbol of revising detects with the interference cancellation unit finishes first group of detection and interference cancellation to the Z group code respectively, and the received signal vector of revising through the detection of group internal symbol and the interference cancellation unit 202 of a correction is used for the group internal symbol detection of next correction and the detection of interference cancellation unit symbol.The group internal symbol of revising detects the signal of all symbols that obtain with interference cancellation unit 202 and estimates to give pretreatment unit 203.Pretreatment unit 203 is detected by the group internal symbol of revising from Z to be estimated with the signal of all symbols of interference cancellation unit and detects and the received signal vector of the correction of interference cancellation unit from Z the group internal symbol of revising, and obtains the received signal vector of the correction of all symbols.The received signal vector of the correction of all symbols walks abreast and gives detecting unit 102 when walking abreast vertical layered space, the parallel detection of detecting unit 102 all symbols when being used for walking abreast vertical layered space.The received signal vector of the correction of symbol estimates that by the group internal symbol detection of revising from Z and the received signal vector of the correction of interference cancellation unit and the signal of this symbol sum constitutes.

Fig. 3 is that i the group internal symbol of revising shown in Figure 2 detects the structural representation with the interference cancellation unit.Referring to Fig. 3, the group internal symbol of each correction detects with the interference cancellation unit and comprises: weight vector computing unit 301, decision-making statistic computing unit 302, transmission sign estimation unit 303, signal are estimated and interference cancellation unit 304.Wherein, weight vector computing unit 301 calculates more than one weight vector according to the estimation of Q matrix, and each weight vector is imported decision-making statistic computing unit 302 successively; Each decision-making statistic computing unit 302 calculates the decision-making statistic according to the received signal vector ri and the weight vector through revising of the output of (i-1) group, and the decision-making statistic that will calculate is sent to coupled transmission sign estimation unit 303.Each sends sign estimation unit 303 according to the decision-making statistic of receiving, estimate the estimated value of corresponding symbol in this group and it is delivered to signal estimation and interference cancellation unit 304, signal estimate that the signal of finishing all symbols in the group by the received signal vector ri of the estimated value of all symbols in the group that receives and correction with interference cancellation unit 304 is estimated and interference cancellation after, the signal of all symbols is estimated to export to pretreatment unit 203, and the group internal symbol that the received signal vector of the correction that will obtain through interference cancellation is given (i+1) individual correction detects and interference cancellation unit/pretreatment unit.The signal estimation of symbol is the amassing of column vector that the estimated value of this symbol row corresponding with this symbol in the corresponding channel estimate matrix constitute.

Referring to Fig. 4, detecting unit 102 comprises signal correction unit 401 when walking abreast vertical layered space, be used to detect the received signal vector of the correction of all symbols, and calculate an above weight vector according to the received signal vector meter of the correction of the estimation of channel matrix and all symbols, calculate the estimated value of corresponding symbol respectively according to each weight vector that calculates, vector carries out one-level parallel interference cancellation at least to received signal, and the received signal vector of the more than one correction that will obtain through interference cancellation is sent to detecting signal unit; Detecting signal unit 402 reappraises value of symbol by the received signal vector of the more than one correction that receives.

Signal correction unit 401 comprises: S-1 level PIC unit, first order PIC unit to the.First order PIC unit detects the received signal vector by the correction of all symbols, estimates all symbols respectively, and all symbols that will estimate again carry out interference cancellation, obtains M the received signal vector of revising, and then it is exported to PIC unit, the second level; PIC unit, the second level detects M received signal vector of the process first order PIC unit correction that receives, estimate M symbol once more, then the symbol that estimates is carried out interference cancellation, obtain M the received signal vector of revising, carry out step by step after the same processing to detecting signal unit 402, i.e. S level PIC unit; S level PIC detects the unit M the received signal vector through revising that its S-1 level that receives provides, and estimates M symbol, and the estimated value of this M symbol is the testing result of multistage parallel interference cancellation structure.

Referring to Fig. 5, (i＜S) level PIC unit comprises that weight vector computing unit 501,1～M decision-making statistic computing unit 502,1～M send sign estimation unit 503, interference cancellation unit 504 to i.Wherein, weight vector computing unit 501 calculates M weight vector, export it to 1～M decision-making statistic computing unit 502 respectively, the received signal vector of the correction of weight vector that each decision-making statistic computing unit 502 basis is received and the respective symbol that receives, calculate a decision-making statistic respectively, and then the decision-making statistic that will calculate exports connected transmission sign estimation unit 503 to.After transmission sign estimation unit 503 estimates symbol, send it to interference cancellation unit 504.Interference cancellation unit 504 receives the symbol that estimates of 1～M transmission sign estimation unit 503 transmissions and the received signal vector of the not any processing of process carries out interference cancellation, obtains M the received signal vector of revising.

Referring to Fig. 6, S level PIC unit comprises that weight vector computing unit 501,1～M decision-making statistic computing unit 502,1～M send sign estimation unit 503.S level PIC unit is similar to the front first order to the (S-1) level PIC unit.Its difference is that afterbody PIC does not comprise the interference cancellation unit in the unit, during just afterbody is handled, directly the sign estimation value is exported as last testing result, and is not carried out interference cancellation after estimating symbol.

Symbol packets is as follows with the process of grouping of resetting unit 201 and rearrangement:

Step 101: symbol packets and of the estimation of rearrangement unit 201 by received signal vector and channel matrix H

(1) according to certain criterion with M symbol a ₁, a ₂..., a _MBe divided into the Z group, i (i=1,2 ..., Z) the group code number is L _i, i organizes L _iIndividual symbol is b _I1, b _I2..., b _ILiWherein,

, represent that it is M that i organizes j symbol sequence number in original assemble of symbol _{I, j}(M _{I, j}∈ [1,2 ..., M]), j=1,2 ..., L _i, the value of j changes with the variation of group number i.

Step 102: with symbol a ₁, a ₂..., a _MReset, the rearrangement result is: b ₁₁, b ₁₂..., b _1L1, b ₂₁..., b _2L2..., b _Z1..., b _ZLZTherefore, Dui Ying transmission symbolic vector is converted to:

$b={[b_{11},b_{12},\&CenterDot;\&CenterDot;\&CenterDot;,b_{{1\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">L</figure-callout>}}_1},b_{21},\&CenterDot;\&CenterDot;\&CenterDot;,b_{{2L}_2},\&CenterDot;\&CenterDot;\&CenterDot;,{\mathrm{<figure-callout\; id="1"\; label="b\; Z"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">b</figure-callout>}}_Z,\&CenterDot;\&CenterDot;\&CenterDot;,b_{{\mathrm{ZL}}_Z}]}^T$

Channel matrix H in the formula (1) can be write as the form of column vector: H=[H ₁, H ₂..., H _M].

Next, to sequence H ₁, H ₂..., H _MCarry out and sequence a ₁, a ₂..., a _MSame rearrangement, the sequence that obtains are Q ₁, Q ₂..., Q _M, note Q=[Q ₁, Q ₂..., Q _M].

Like this, reset through the element of H and a, formula (1) can upgrade as follows:

r ₁＝Qb+v (1a)

Step 103: symbol packets and the estimation of resetting the channel matrix Q after unit 201 will upgrade Sending to Z the group internal symbol of revising detects and interference cancellation unit 202.

Can pass through

Rearrangement obtain.

Need to prove that in the above-described embodiments, the calculating of weight vector can adopt different optimization criterions to calculate, such as, ZF criterion and MMSE criterion etc.And each sends the sign estimation unit can adopt existing hard decision function, and as quantization function, or the soft-decision function carries out the estimation of symbol.When adopting the soft-decision function, each sends the sign estimation unit can be calculated corresponding transmission symbol according to formula (7) by the decision-making statistic that receives estimation.

_j＝D(y _j)，j＝1，2，…，M (7)

In formula (7), j sends the sign estimation unit by j decision-making statistic y _jObtain j estimated value that sends symbol.

In formula (7), substituted quantization function Q () in formula (3) and the formula (6f) with soft-decision function D ().

The decision-making statistic can be expressed as follows in the formula (7):

y _j＝a _j+v _j，j＝1，2，…，M (7-1)

Wherein, a _j∈ { A ₁, A ₂..., A _K, { A ₁, A ₂..., A _KIt is the set that all possible transmission symbol constitutes; v _jIt is white Gaussian noise.

Then specifically calculate according to following formula (7):

${\hat{a}}_j=D\left(y_j\right)={\mathrm{\&beta;}}_j\frac{\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}{A}_{k}f\left(y_i\right|A_k)}{\underset{k=1}{\overset{K}{\mathrm{\&Sigma;}}}f\left(y_j\right|A_k)},j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,M---(7-2)$

Wherein, β _jBe called correction factor, estimate the deviation of the undesirable sign estimation that causes and the deviation of interference cancellation in order to correction channel; F (y _j| A _k) represent that sending symbol is A _kThe time receive y _jProbability density function.β _jAnd f (y _j| A _k) computational methods as follows:

(1) if the symbol that sends is a plural number, then

$f\left(y_j\right|A_k)=\frac{1}{2{\mathrm{\&pi;\&sigma;}}_j^2}{e}^{\frac{{({\mathrm{YR}}_j-{\mathrm{AR}}_k)}^2+{({\mathrm{YI}}_j-{\mathrm{AI}}_k)}^2}{2{\mathrm{\&sigma;}}_j^2}}---(7-3)$

Wherein, AR _k, AI _kBe respectively A _kReal part and imaginary part; YR _j, YI _jBe respectively y _jReal part and imaginary part; VR _j, VI _iBe respectively v _jReal part and imaginary part, obey respectively N (0, σ _j ²) distribute, and β _jIt is plural number.

(2) if sending symbol is real number, then

$f\left(y_j\right|A_k)=\frac{1}{\sqrt{2\mathrm{\&pi;}}{\mathrm{\&sigma;}}_j}{e}^{-\frac{{({\mathrm{YR}}_j-2A_k)}^2}{2{\mathrm{\&sigma;}}_j^2}}---(7-4)$

Wherein, YR _jBe y _jReal part; VR _jBe v _jReal part, obey N (0, σ _j ²) distribute.And β _jIt is real number.

(3) β _jThe value and the SNR of symbol closely related, the function of the SNR of is-symbol.

In order to simplify calculating, also can directly make β _j=1, that is: the deviation of not considering channel estimating influence that sign estimation and interference cancellation are caused.

Grouping during vertical layered space in the detecting unit 101 computational methods of weight vector as follows:

Under the ZF criterion, in the detection of group internal symbol and interference cancellation unit of first correction, can be by the estimation of channel matrix Q

Calculate the ZF weight vector according to formula (8a) and formula (8b):

${\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">G</figure-callout>}}_1={\left(\hat{Q}\left(1\right)\right)}^{+}---\left(8a\right)$

${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">w</figure-callout>}}_{1,j}={\left(G_1\right)}_j^T,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,L_1---\left(8b\right)$

Wherein, L ₁The number of representing the 1st group element.Under the ZF criterion, i (when the group code of 1＜i≤Z) detects, can be by channel matrix Calculate the ZF weight vector according to formula (8c) and formula (8d):

$G_i={\left(\hat{Q}\left(i\right)\right)}^{+}---\left(8c\right)$

$w_{i,j}={\left(G_i\right)}_{J+j}^T,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,L_i,J=\underset{k=1}{\overset{i=1}{\mathrm{\&Sigma;}}}{L}_k---\left(8d\right)$

Wherein, L _iThe number of representing the i group element.

The estimation of channel matrix Q when being illustrated in the detection of i group.

Do not carrying out under the situation of channel estimating channel matrix again

Before $J=\underset{k=1}{\overset{i-1}{\mathrm{\&Sigma;}}}{L}_k$ Classify 0 column vector as, and (J+1) row are classified to M as

(J+1) row be listed as to M.Again carrying out under the situation of channel estimating channel matrix Before $J=\underset{k=1}{\overset{i-1}{\mathrm{\&Sigma;}}}{L}_k$ Classify 0 column vector as, and (J+1) row are listed as by channel estimating to M and obtain.Wherein, j ∈ [J+1, M] row newly carry out channel estimating and obtain by j ∈ [J+1, the M] column weight to the Q matrix.

Under the MMSE criterion, in the detection of group internal symbol and interference cancellation unit of first correction, can be by channel matrix

Calculate weight vector according to formula (9a) and formula (9b):

${\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">G</figure-callout>}}_1={\mathrm{\&sigma;}}_s^2{F}^H{[{\mathrm{\&sigma;}}_s^2{\mathrm{FF}}^H+{\mathrm{\&sigma;}}^2{I}_M]}^{-1},F=\left(\hat{Q}\left(1\right)\right)---\left(9a\right)$

${\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">w</figure-callout>}}_{1,j}={\left(G_1\right)}_j^T,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,L_1---\left(9b\right)$

Under the MMSE criterion, i (when the group code of 1＜i≤Z) detects, can be by channel matrix Calculate weight vector according to formula (9c) and formula (9d):

${\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="A20041005005200232.png"\; state="\{\{state\}\}">G</figure-callout>}}_1={\mathrm{\&sigma;}}_s^2{F}^H{[{\mathrm{\&sigma;}}_s^2{\mathrm{FF}}^H+{\mathrm{\&sigma;}}^2{I}_M]}^{-1},F=\left(\hat{Q}\left(i\right)\right)---\left(9c\right)$

$w_{i,j}={\left(G_i\right)}_{J+j}^T,j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,L_i,J=\underset{k=1}{\overset{i-1}{\mathrm{\&Sigma;}}}{L}_k---\left(9d\right)$

Do not carrying out under the situation of channel estimating channel matrix again

Before $J=\underset{k=1}{\overset{i-1}{\mathrm{\&Sigma;}}}{L}_k$ Classify 0 column vector as, and (J+1) row are classified to M as

(J+1) row be listed as to M.Again carrying out under the situation of channel estimating channel matrix Before $J=\underset{k=1}{\overset{i-1}{\mathrm{\&Sigma;}}}{L}_k$ Classify 0 column vector as, and (J+1) row are listed as by channel estimating to M and obtain.Wherein, j ∈ [J+1, M] row newly carry out channel estimating and obtain by j ∈ [J+1, the M] column weight to the Q matrix.

During parallel vertical layered space in the detecting unit 102 computational methods of weight vector as follows:

Under the ZF criterion, at i (in the level of 1≤i≤s) the parallel interference cancellation structure, in that carry out again can be by channel matrix under the channel estimation case (i) calculate weight vector according to formula (10a):

$w_{i,j}=\frac{{\left(\hat{H}\left(i\right)\right)}_j^{*}}{{\left|\right|{\left(\hat{H}\left(i\right)\right)}_j\left|\right|}^2},i=1,\&CenterDot;\&CenterDot;\&CenterDot;,S;j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,M---\left(10a\right)$

In the following formula,

Expression

J row, ‖ B ‖ ²=B ^HB, B are column vector,

It is the estimation of channel matrix H in i level PIC structure.Under the ZF criterion, i (in the level of 1≤j≤s) the parallel interference cancellation structure, do not carrying out again under the channel estimation case, can be by the estimation of channel matrix in the previous stage PIC structure

(10b) calculates weight vector according to formula:

$w_{i,j}=\frac{{\left(\hat{H}(i-1)\right)}_j^{*}}{{\left|\right|{\left(\hat{H}(i-1)\right)}_j\left|\right|}^2},i=1,\&CenterDot;\&CenterDot;\&CenterDot;,S;j=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,M---\left(10b\right)$

Under the MMSE criterion, at i (in the level of 1≤i≤s) the parallel interference cancellation structure, in that carry out again can be by the estimation of channel matrix under the channel estimation case

(10c) calculates weight vector according to formula:

$w_{i,j}={\left({\mathrm{\&sigma;}}_s^2{F}^H{[{\mathrm{\&sigma;}}_s^2{\mathrm{FF}}^H+{\mathrm{\&sigma;}}^2{I}_M]}^{-1}\right)}^T,F={\left(\hat{H}\left(i\right)\right)}_j---\left(10c\right)$

Wherein, σ ²Be the power of noise component(s) in the received signal vector, σ _s ²For sending the power of symbol.Under the MMSE criterion, at i (in the level of 1≤i≤s) the parallel interference cancellation structure, in that do not carry out again can be by the estimation of channel matrix under the channel estimation case (10d) calculates weight vector according to formula:

$w_{i,j}={\left({\mathrm{\&sigma;}}_s^2{F}^H{[{\mathrm{\&sigma;}}_s^2{\mathrm{FF}}^H+{\mathrm{\&sigma;}}^2{I}_M]}^{-1}\right)}^T,F={\left(\hat{H}(i-1)\right)}_j---\left(10d\right)$

Wherein, σ ²Be the power of noise component(s) in the received signal vector, σ _s ²For sending the power of symbol.

In a word, the above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention.

Claims (7)

1, a kind of receiver of multi-input multi-output system is characterized in that, this receiver comprises:

Detecting unit (101) during the grouping vertical layered space, be used for the received signal vector, symbol to be detected in all received signal vectors is divided into some groups, finish grouping and detect during vertical layered space, the received signal vector of correction of exporting all symbols detecting unit (102) during to parallel vertical layered space;

Detecting unit (102) when walking abreast vertical layered space, the received signal vector of all symbols that detecting unit (101) is revised when being used for receiving through the grouping vertical layered space, after detecting when walking abreast vertical layered space by the received signal vector of the correction of all symbols, the estimation of exporting each symbol.

2, receiver according to claim 1, it is characterized in that, detecting unit (101) comprising during described grouping vertical layered space: symbol packets with reset unit (201), the group internal symbol with last correction detects and interference cancellation unit (202) and pretreatment unit (203), wherein

Symbol packets and rearrangement unit (201), the transmission symbolic vector and the channel matrix that be used for the received signal vector, constitute with all symbol packets to be detected of received signal vector, with symbol to be detected in all received signal vectors are reset, and the group internal symbol that the received signal vector exports first correction to is detected and interference cancellation unit (202);

The group internal symbol of each correction detects and interference cancellation unit (202), detect group internal symbol corresponding in the received signal vector of importing, obtaining the estimated value of all symbols in this group and the signal of all symbols estimates, and detected all symbols are carried out interference cancellation, the received signal vector that obtains revising is as the group internal symbol detection of next one correction and the received signal vector to be detected/pending received signal vector of interference cancellation unit/pretreatment unit (203), and the signal of all symbols estimates to deliver to pretreatment unit (203) in the group;

Pretreatment unit (203), the group internal symbol that receives all corrections detects to be estimated with the signal of all symbols of interference cancellation unit (202) and the group internal symbol of last correction detects received signal vector with the correction of interference cancellation unit, obtain the received signal vector of the correction of all symbols, the received signal vector of the correction of described symbol estimates that with the received signal vector of the correction of interference cancellation unit and the signal of this symbol sum constitutes by the group internal symbol detection of last correction.

3, receiver according to claim 2 is characterized in that, the group internal symbol of described correction detects with interference cancellation unit (202) and comprising:

Weight vector computing unit (301) is used for calculating one with last weight vector according to the estimation of channel matrix, and exports each weight vector to corresponding decision-making statistic computing unit (302);

One is used for the received signal vector with last decision-making statistic computing unit (302), and determines the decision-making statistic according to the weight vector that receives, and exports it to transmission sign estimation unit (303);

One with last transmission sign estimation unit (303), estimate to send symbol according to the decision-making statistic that receives, and the estimated value that will send symbol exports signal to and estimates and interference cancellation unit (304);

Signal is estimated and interference cancellation unit (304), all send the estimated value of symbol in received signal vector and the group, and estimate according to the signal that the estimated value that sends symbol obtains sending symbol, and vector carries out interference cancellation to received signal, obtain the received signal vector of a correction and export it to next group internal symbol of revising detecting and interference cancellation unit/pretreatment unit (203), and the signal that will send symbol estimates to deliver to pretreatment unit (203), and the signal of described transmission symbol is estimated as the amassing of column vector that the estimated value row corresponding with this symbol in the corresponding channel estimate matrix of this symbol constitute.

4, receiver according to claim 1 is characterized in that, detecting unit (102) comprising during described parallel vertical layered space:

Signal correction unit 401, be used to detect the received signal vector of the correction of all symbols, and calculate an above weight vector according to the received signal vector meter of the correction of the estimation of channel matrix and all symbols, calculate the decision-making statistic of corresponding symbol respectively according to each weight vector that calculates, calculate the estimated value of this symbol by the decision-making statistic of this symbol, vector carries out one-level parallel interference cancellation at least to received signal, and the received signal vector of the more than one correction that will obtain through interference cancellation is sent to detecting signal unit;

Detecting signal unit 402 reappraises value of symbol by the received signal vector of the more than one correction that receives.

5, device according to claim 4 is characterized in that, described signal correction unit comprises:

At least one-level parallel interference cancellation unit is connected in series between every grade of parallel interference cancellation unit, and afterbody parallel interference cancellation unit links to each other with detecting signal unit,

Wherein, described parallel interference cancellation unit is used for the received signal vector, and calculates an above weight vector; Decision-making statistic according to each weight vector parallel computation symbol correspondence; Utilize each decision-making statistic to carry out the estimation of symbol, obtain more than one sign estimation value; And then described more than one sign estimation value and received signal vector carried out interference cancellation; The received signal vector of the more than one correction that will obtain through interference cancellation exports next stage parallel interference cancellation unit/detecting signal unit to.

6, device according to claim 5 is characterized in that, described parallel interference cancellation unit comprises:

Weight vector computing unit (501) is used for calculating one with last weight vector according to the estimation of channel matrix, and exports it to each decision-making statistic computing unit (502);

One is used for the received signal vector with last decision-making statistic computing unit (502), and determines the decision-making statistic according to the weight vector that receives, and exports it to transmission sign estimation unit (503);

Estimate the transmission symbol with last transmission sign estimation unit (503) according to the decision-making statistic that receives, and export it to interference cancellation unit (504) for one;

Interference cancellation unit (504), received signal vector and all send the estimated value of symbol, and according to all estimated values that send symbols to received signal vector carry out interference cancellation, obtain the received signal vector revised more than one and export it to next stage parallel interference cancellation unit/detecting signal unit.

7, device according to claim 4 is characterized in that, described detecting signal unit comprises:

Weight vector computing unit (501) is used for calculating one with last weight vector according to the estimation of channel matrix, and exports it to each decision-making statistic computing unit (502);

One is used to receive the received signal vector of correction with last decision-making statistic computing unit (502), and determines the decision-making statistic according to each weight vector that weight vector computing unit (501) calculates, and exports it to transmission sign estimation unit (503);

Estimate to send symbol according to the decision-making statistic that receives with last transmission sign estimation unit (503), obtain sending more than one the estimated value of symbol for one.

Images