CN102035787B - Band sequencing Turbo enhancement method for multiple-input multiple-output-orthogonal frequency division multiplexing (MIMO-OFDM) wireless communication receiver - Google Patents

Abstract

The invention provides a band sequencing Turbo enhancement method for a multiple-input multiple-output-orthogonal frequency division multiplexing (MIMO-OFDM) wireless communication receiver. The method comprises the following steps of: (1) caching an equilibrium former frequency domain baseband signal R, taking the cached baseband signal out and linearly equalizing the cached baseband signal, and judging the equalized baseband signal R to further acquire a frequency domain estimation value of each layer of baseband signal component of each subchannel; (2) calculating a sequencing index of the domain estimation value of each layer of baseband signal component of each subchannel and sequencing the domain estimation value of each layer of baseband signal component of each subchannel according to a calculated result; and (3) according to the sequencing result of the domain estimation value of each layer of baseband signal component of each subchannel acquired in the step (2), performing Turbo enhancement on the domain estimation value of each layer of baseband signal component of each subchannel sequentially. By the method, the performance of the MIMO-OFDM wireless communication receiver can be remarkably improved under the condition of not improving complexity and increasing calculated quantity greatly.

Description

A kind of tape sort Turbo Enhancement Method of MIMO-OFDM wireless communication receiver

Technical field

The present invention relates to a kind of many antennas broadband wireless communications transmission method, belong to the broadband wireless communication technique field.

Background technology

Along with development of internet technology, people also improve constantly the requirement of access network, enter the Internet at a high speed whenever and wherever possible and become increasing people's important need, wireless communication technology is to satisfy the main support technology of people's the demand, and therefore broadband wireless communication technique has obtained fast development in recent years.Increase along with transmission rate, the multipath that the electromagnetic wave radio transmission causes is more and more serious to systematic influence, generally speaking the frequency selective fading that exists multipath transmisstion to cause inevitably in the system of broadband wireless communication, frequency selective fading once were one of principal elements of restriction performance in wireless communication systems.By OFDM (Orthogonal Frequency Division Multiplexing, hereinafter to be referred as OFDM) technical development get up based on Cyclic Prefix (Cyclic Prefix, hereinafter to be referred as CP) piecemeal transmission technology (mainly comprising OFDM, single carrier frequency domain equalization etc.) be the simple and highly effective technology that tackles the frequency selective fading that multipath transmisstion causes in the broadband wireless communications, so OFDM becomes the mainstream technology of present broadband wireless communications.Spectrum efficiency is the research emphasis of wireless communication technology always, adopt multiple-input and multiple-output (Multiple-Input Multiple-Output is hereinafter to be referred as the MIMO) technology of multi-antenna technology to be beyond one's reach spectrum efficiency and to be subjected to extensive concern with its conventional single-antenna technology based on transmitting-receiving two-end in recent years.MIMO and OFDM technology become the main support technology of future wireless physical layer transmission in conjunction with the MIMO-OFDM that occurs, by 3GPP LTE (Long Term Evolution, the descending transmission technology of adopting as its physical layer LTE).

MIMO utilizes in the wireless propagation environment with rich multipath the uncorrelated characteristic of channel between the different antennae, obtains the high channel capacity, thereby improves the availability of frequency spectrum and reliability.OFDM based on the piecemeal transmission can resist multipath fading effectively, because the subcarrier spectrum main lobe is overlapping, has higher spectrum efficiency; CP can well absorb inter-frame-interference; And can take simple frequency-domain equilibrium method to eliminate because the channel disturbance that the time delay expansion is introduced; The baseband modulation process of OFDM can be used invert fast fourier transformation (Inverse Fast Fourier Transform, hereinafter to be referred as IFFT) finish, the base band demodulating process can be used fast fourier transform (Fast Fourier Transform, hereinafter to be referred as FFT)) finish, have the simple advantage of realization.

Fig. 1 has provided a N _T* N _RWideband MIMO-OFDM wireless communication system schematic diagram, suppose N here _T≤ N _R, be a space division multiplex wireless communication system, wherein the effect of each module is as follows:

MIMO transmitting terminal processing module 1: produce and want the information transmitted bit, carry out sign map, inverse Fourier transform (IFFT) adds Cyclic Prefix (CP), radio frequency, intermediate frequency Modulation and Base-Band Processing.Sign map is that the information bit that information source produces is mapped on the planisphere corresponding points according to the sign map mode that adopts; Inverse Fourier transform (IFFT) is to transform to time domain with obtaining frequency-region signal; Adding CP is that the every frame data that will obtain add Cyclic Prefix; Radio frequency, intermediate frequency Modulation and Base-Band Processing are to modulate the signal to carry out the intermediate frequency amplification on the intermediate frequency, do rf modulations again, at last modulated signal are launched by antenna.

Radio frequency, intermediate frequency demodulation and baseband processing module 2: the frequency spectrum that reception antenna is received signal is moved low frequency from radio frequency or intermediate frequency.Before demodulation, need with the frequency deviation that causes in the synchronization module correction signal transmission course and and obtain correct timing information.

Go CP module 3: Cyclic Prefix is removed according to timing information.

N point FFT module 4: the time-domain signal that will remove CP transforms to frequency domain.

Linear equalization module 5: carry out equilibrium with balanced matrix.Balanced way can be selected one of following two kinds of balanced ways: ZF (Zero Forcing, ZF) balanced, least mean-square error (Minimum Mean Square Error, MMSE) equilibrium.

Judgement output module 6: according to the sign map mode that system adopts, finish judgement and the output of signal.

N among Fig. 1 _TThe expression number of transmit antennas, N _RRepresent the reception antenna number, the base band signal process process of MIMO-OFDM system only is discussed here.Making a start,

Frequency domain data frame to be sent after the expression sign map, wherein

The frequency domain data frame of i root antenna after the expression sign map, i ∈ (1,2 ..., N _T),

The frequency domain data frame of k subchannel (being also referred to as k subcarrier) after the expression sign map, k ∈ (0,1 ..., N-1), () ^TThe transposition of representing matrix or vector; Typical sign map mode is QAM and the PSK sign map of various system numbers;

Average power for information symbol.After X is N point IFFT and transforms to time domain and add CP respectively by N _TTransmit antennas sends.In the MIMO communication system, claim that traditionally the signal of transmit antennas emission is one deck, each layer signal has N symbol, can tie up matrix notation with a N * 1; Transmitting of the corresponding different layers of different transmit antennas, the signal that the i transmit antennas sends is called the i layer, and we are called the i layer signal component of k subchannel for the signal of the i transmit antennas transmission of k subchannel.At transmitting terminal, because each layer data disperses before carrier modulation, be called symbol or information bit traditionally, because each layer data becomes continuous waveform, be called signal traditionally after the carrier modulation; At receiving terminal because each layer data before the judgement is continuous waveform, be called signal traditionally since judgement after each layer data become discretely, be called symbol or information bit traditionally.

Be the time domain channel that intersymbol interference (time delay expansion) arranged between i transmit antennas and l root reception antenna, wherein, i ∈ (1,2 ..., N _T), l ∈ (1,2 ..., N _R); Generally speaking,

Having only preceding L component right and wrong 0, L is the length of maximum delay expansion.To h _{L, i}Carry out FFT and obtain frequency domain channel between i transmit antennas and l root reception antenna

Be the channel matrix of k subchannel, be expressed as

$H_N^k=\left[\begin{array}{cccc}{H}_{11}^k& H_{12}^k& \·\·\·& H_{1N_T}^k\\ H_{21}^k& H_{22}^k& \·\·\·& H_{2N_T}^k\\ \·\·\·& \·\·\·& \·\·\·& \·\·\·\\ H_{N_{R}1}^k& H_{N_{R}2}^k& \·\·\·& H_{N_R{N}_T}^k\end{array}\right]$

Wherein, k ∈ (0,1 ..., N-1).Transmit through behind the mimo channel, through mimo wireless communication receiver radio frequency, intermediate frequency demodulation and Base-Band Processing and after removing CP, the baseband signal that l root reception antenna receives is

$r_{N,l}={(r_{N,l}^0,\·\·\·,r_{N,l}^{N-1})}^T=y_{N,l}+w_{N,l}$

Wherein,

Be the useful signal part that l root reception antenna receives, the convolution with channel of namely transmitting,

Be the noise vector on the l root reception antenna,

Wherein Be additive white Gaussian noise

Variance, k ∈ (0,1 ... N-1), l ∈ (1,2 ..., N _R).Then, be N point FFT and obtain receiving the signal frequency-domain form

In the expression formula

Wherein

Be useful signal y _{N, l}Frequency domain form,

Be noise vector w _{N, l}Corresponding frequency domain form.On k the subchannel,

Wherein, signal component is

Noise component(s) is

K ∈ (0,1 ... N-1).

Adopt the MIMO receiver of linear equalization mode to be called decorrelation or decorrelation receiver (Decorrelator) again, on k subchannel, this receiver is with a balanced matrix

Remove multiply by received signal vector

Finish to received signal decorrelation or equilibrium:

${\left(R_e\right)}_N^k={\left(D_N^k{\left(R_N^k\right)}^T\right)}^T$

Signal after the equilibrium is adjudicated, and the information bit after obtaining adjudicating carries out sign map to the information bit after the judgement again by transmitting terminal sign map mode, can also obtain the frequency domain estimated value of each respective symbol

Wherein

I ∈ (1,2 ..., N _T), be the frequency domain estimated value of i layer emission symbol,

K ∈ (0,1 ... N-1), be k the N on the subchannel _TThe frequency domain estimated value of layer signal component, when not adjudicating error code,

Linear equalization mode commonly used has two kinds, i.e. ZF (Zero Forcing, ZF) balanced and least mean-square error (Minimum Mean Square Error, MMSE) equilibrium, the balanced matrix difference of these two kinds of balanced ways, wherein on k subchannel, the balanced matrix of ZF equilibrium is channel matrix Generalized inverse (it is contrary to be also referred to as M-P) Namely

${\left(D_N^k\right)}_{\mathrm{ZF}}={\left(H_N^k\right)}^{+}$

K subchannel, the balanced matrix of MMSE equilibrium is

${\left(D_N^k\right)}_{\mathrm{MMSE}}={({\left(H_N^k\right)}^H{H}_N^k+\frac{{\mathrm{\σ}}_w^2}{E_s}{I}_{N_T})}^{-1}{\left(H_N^k\right)}^H$

Wherein,

Be noise variance; E _sThe average transmit power of representing each emission symbol, () ^HThe expression conjugate transpose.

Adopt the MIMO-OFDM decorrelation receiver easy realization simple in structure of above-mentioned linear equalization mode, but its performance is often relatively poor, adopt the decorrelation receiver performance of MMSE balanced way generally much better than the decorrelation receiver that adopts the ZF equilibrium, but also often can not practical requirement, often will be in conjunction with the very strong error-correcting code system of error correcting capability, just can practical application.However, because its simplicity, the MIMO-OFDM that 3GPP LTE is descending and up MIMO-SCFDE system generally still adopt linear equalization (generally being the MMSE equilibrium) mode to carry out the processing of receiving terminal, and this can save the manufacturing cost of receiver greatly.

Disturb inhibition (Successive Inference Cancelation based on order, SIC) receiver, owing to adopted good interference mitigation technology, make that the interference between different layers alleviates greatly, the general remarkable decorrelation receiver that is better than based on linear equalization of performance.Typical case's representative based on the MIMO receiver of SIC is BLAST (the Bell Laboratories Layered Space-Time Architecture) receiver that Bell laboratory G Foschini proposes, though it is high that its V-BLAST is subjected to extensively chasing after of academia, but because complexity is too high and to the sensitiveness of channel measurement error, still do not accepted extensively by industrial quarters so far.This SIC detection method can be directly used in the input of MIMO-OFDM.

Though the decorrelation receiver based on linear equalization is simple in structure, accepted extensively poor-performing by industrial quarters.

Summary of the invention

The present invention is directed to the problem of the poor performance of existing linear equalization receiver existence, a kind of advantage that can keep decorrelation receiver easy realization simple in structure is provided, can makes the tape sort Turbo Enhancement Method of the MIMO-OFDM wireless communication receiver that its performance is significantly improved again.Must be pointed out that the Turbo code in Turbo Enhancement Method of the present invention and the error correcting code does not have direct relation, the present invention does not rely on any error correcting code.

The tape sort Turbo Enhancement Method of MIMO-OFDM wireless communication receiver of the present invention may further comprise the steps:

(1) buffer memory MIMO-OFDM wireless communication receiver receive balanced before frequency domain baseband signal R, take out the baseband signal R of buffer memory and it is carried out linear equalization, baseband signal after the equilibrium is adjudicated, obtain the information bit of each layer baseband signal component of each subchannel, and further obtain the frequency domain estimated value of each layer baseband signal component of each subchannel;

(2) calculate the ordering index of frequency domain estimated value of each layer baseband signal component of each subchannel, and sort according to the frequency domain estimated value of result of calculation to each layer baseband signal component of each subchannel;

(3) ranking results of the frequency domain estimated value of each layer baseband signal component of each subchannel that obtains according to step (2) carries out Turbo to the frequency domain estimated value of each layer baseband signal component of each subchannel successively in order and strengthens; The frequency domain estimated value of each layer baseband signal component of each subchannel of baseband signal all once strengthened to be called take turns Turbo and strengthen, according to the requirement to receiver performance and complexity aspect, carry out taking turns Turbo at least and strengthen.

The specific implementation method of above steps is as follows:

In the step (1), the baseband signal R of buffer memory is carried out linear equalization can adopt ZF equilibrium or MMSE equilibrium.The method that baseband signal after the equilibrium is adjudicated is identical with the method for common MIMO-OFDM wireless communication receiver.The method of frequency domain estimated value that obtains each layer baseband signal component of each subchannel is: the information bit to each subchannel after the judgement carries out sign map again by transmitting terminal sign map mode, obtains the frequency domain estimated value of each layer baseband signal component of each subchannel

$\hat{X}={({\hat{X}}_N^0,\·\·\·,{\hat{X}}_N^{N-1})}^T.$

In the step (2), the method for ordering index of frequency domain estimated value of each layer baseband signal component of calculating each subchannel is as follows:

When adopting the ZF equalizer, for k subchannel, after the ordering index of the frequency domain estimated value of each layer baseband signal component is the equilibrium of each layer signal component of current subchannel

Wherein, the ordering index of the frequency domain estimated value of the i layer signal component of k subchannel is

K ∈ (0,1 ..., N-1), i ∈ (1,2 ..., N _T), () ⁱI row vector of representing matrix;

When adopting the MMSE equalizer, for k subchannel, after the ordering index of the frequency domain estimated value of each layer baseband signal component is the equilibrium of each layer signal component of current subchannel

Perhaps balanced back noise suppressed coefficient

For k subchannel, SINR after adopting equilibrium ^kThe time, the ordering index of the frequency domain estimated value of the i layer signal component of k subchannel is I ∈ (1,2 ..., N _T), k ∈ (0,1 ..., N-1), () _iI column vector of representing matrix; For k subchannel; NS after adopting equilibrium ⁱThe time, the ordering index of the frequency domain estimated value of the i layer signal of k subchannel is

Diag wherein _iI the diagonal element of () representing matrix (); When using balanced back noise suppressed coefficient to sort index, its computing formula and balanced matrix are closely similar, for k subchannel, if order

Then

To calculate

The time G that uses ^kThe result store, be used for calculating balanced back noise suppressed coefficient, to reduce amount of calculation and the complexity of system.

In the step (2), as follows to the method that the frequency domain estimated value of each layer baseband signal component of each subchannel sorts according to result of calculation:

For k subchannel, to signal to noise ratio snr after the equilibrium ^kOr balanced back signal interference noise power compares SINR ^kOr balanced back noise suppressed coefficient NS ^kCarry out ascending arrangement, obtain 1 * N _TDimension ordering matrix

Wherein,

I=1,2 ..., N _TFor SNR ^k, SINR ^kAnd NS ^kSatisfy respectively

Perhaps With

Said method is the ascending ordering of frequency domain estimated value to each layer baseband signal component of each subchannel.To the frequency domain estimated value of each layer baseband signal component of each subchannel also can be descending ordering, its method is opposite with above-mentioned ascending sort method.

In the step (3), it is as follows successively the frequency domain estimated value of each layer baseband signal component of each subchannel to be carried out taking turns the concrete grammar that Turbo strengthens in order:

Obtain arranging vector according to step (2)

At first handle the 0th subchannel, the frequency domain estimated value that obtains from step (1)

In, the frequency domain estimated value of taking out the 0th subchannel

S ₁The frequency domain estimated value of other each layer signal components beyond the layer is used for the s that the reconstruct receiver receives ₁The frequency-region signal that other each layers beyond the layer transmit, wherein,

I ∈ 1 ... N _TBe the transmit reconstruct of component of the i layer of the 0th subchannel that receiver is received, () ^TThe transposition of representing matrix or vector;

I ∈ 1 ... N _TBe the 0th subchannel that receiver is received except transmit other N the component of i layer _TThe reconstruct of-1 layer of component that transmits; Take out the balanced preceding frequency domain baseband signal of buffer memory then Deduct the s that removes of the 0th subchannel with the signal of buffer memory ₁Layer other N beyond the component that transmits _TThe reconstruction signal of-1 layer of component that transmits, namely With the signal that obtains

Premultiplication

Obtain And adjudicate, obtain the s of the 0th subchannel ₁The layer signal component

Here, C is N * N _TDimension judgement output matrix,

Represent k row vector,

Expression

I component; Will

Again carry out sign map by transmitting terminal sign map mode, upgrade former frequency domain estimated value with current mapping signal

In

Handle the s of the 0th subchannel with identical method ₂The layer signal component, until

The layer signal component, the current subchannel that each reconstruct receiver receives transmit during component the frequency domain estimated value of use latest update when other layers beyond the anterior layer

This moment, the 0th subchannel Turbo enhancing finished; Handle the 1st subchannel with identical method, until the N-1 subchannel.

ZF is balanced identical with the Turbo Enhancement Method of MMSE equilibrium.

Specific implementation is carried out taking turns Turbo to the frequency domain estimated value of each layer baseband signal component of each subchannel successively in order and is strengthened according to the following steps:

①for?k＝0，1，…，N-1

②for?

③ $Z_N^k=R_N^k-\underset{n\≠i}{\overset{N_T}{\mathrm{\Σ}}}{\hat{X}}_{N,n}^k{\left({\left(H_N^k\right)}_n\right)}^T,n=1,\·\·\·N_T$

④ $V={\left({\left(H_N^k\right)}_i\right)}^{+}{\left(Z_N^k\right)}^T$

⑤ ${\left(C_N^k\right)}_i=D\left(V\right)$

⑥ ${\hat{X}}_{N,i}^k=Q\left({\left(C_N^k\right)}_i\right)$

⑦End?for

⑧End?for?k＝0，1，…，N-1

Wherein, Q () represents sign map, and D () represents judgement, () _iI column vector of representing matrix or i the vectorial component of going, () ^TThe transposition of representing matrix or vector; Step 5. middle C is N * N _TDimension judgement output matrix,

Represent k row vector,

Expression

I component; The i layer signal component of k the subchannel of step in 6.

Value upgrade, be used for the Turbo enhancing that first round Turbo strengthens other layer signal component of k the subchannel in back.

In the step (3), it is as follows successively the frequency domain estimated value of each layer baseband signal component of each subchannel to be carried out the concrete grammar that many wheel Turbo strengthen in order:

The wheel that maximum Turbo enhancing is set is counted T, and the value of T can arrange general 2≤T≤N voluntarily according to performance and complexity needs _T+ 2*log ₂(M), N here _TBe number of transmit antennas, M is-symbol mapping system number (being also referred to as modulation system number); One takes turns after Turbo strengthens, whether the result was identical with Turbo enhancing back result before relatively Turbo strengthened, if it is inequality, carrying out next round Turbo strengthens, strengthen result and current Turbo until previous round Turbo and strengthen to come to the same thing or reach the maximum that Turbo strengthens wheel number T is set, take turns Turbo more and strengthen end.

The present invention is further processed the signal of linear equalizer output, only increase complexity seldom, substantially the advantage that has kept the easy realization simple in structure of original decorrelation receiver can make the performance of this decorrelation receiver be significantly improved simultaneously.Do not have under the situation of very big increase in complexity and amount of calculation, can obviously improve the performance of MIMO-OFDM wireless communication receiver.

Description of drawings

Fig. 1 is the fundamental block diagram of MIMO-OFDM wireless communication system.

Fig. 2 is the realization block diagram of the tape sort Turbo Enhancement Method of MIMO-OFDM wireless communication receiver of the present invention.

Fig. 3 is the errored bit curve chart of the tape sort Turbo Enhancement Method of MIMO-OFDM wireless communication receiver of the present invention when adopting MMSE balanced.

Among the figure: 1, MIMO-OFDM transmitting terminal processing module, 2, radio frequency, intermediate frequency demodulation and baseband processing module, 3, go the CP module, 4, FFT module (N point), 5, the linear equalization module, 6, the judgement output module, 7, Turbo strengthens module, 8, output module.

Embodiment

What embodiment provided is the simulation result that utilizes tape sort Turbo Enhancement Method of the present invention with the MIMO-OFDM wireless communication receiver of MMSE equilibrium.

Fig. 2 has provided the block diagram of the tape sort Turbo Enhancement Method that realizes MIMO-OFDM wireless communication receiver of the present invention, and the receiver that The present invention be directed to space division multiplex wireless communication system shown in Figure 1 improves, the N that provides at Fig. 1 _T* N _RThe basis of wideband MIMO-OFDM wireless communication system on increased Turbo and strengthened module 7 and output module 8, the effect of these two modules is as follows:

Turbo strengthens module 7: finish ordering described in the invention and Turbo Enhancement Method.

Output module 8: output signal.

This embodiment simulation parameter:

Simulated environment: MATLAB R2010a

Subchannel sum: N=2048

CP length: 128

Number of transmit antennas: 4

Reception antenna number: 4

Sign map mode: 4QAM

Sampling rate: 20M sampling/second

The wheel number that maximum Turbo strengthens: T=N _T+ log ₂(M)

The average received signal to noise ratio scope of emulation: SNR=4～20 (dB)

Error correction coding: do not use

Simulated channel environment: adopt 4 * 4 IMT2000A channels, what use in the present embodiment is a static channel sample of IMT2000A channel, this sample uses the mt19937ar randomizer to produce, and the seed in the mt19937ar randomizer is made as 2010; IMT2000A channel in the present embodiment is not considered correlation between transmitting antenna and the correlation between reception antenna.

Do not consider in the emulation that to the influence of system, the error of namely supposing all synchronization parameters all is 0 for channel estimation errors and synchronous error (comprising regularly synchronous error of carrier synchronization error, sampling rate synchronous error and frame); Virtual carrier is not set in the emulation, does not therefore consider the influence of virtual carrier; Do not consider the influence (for example device non-linear etc.) of other non-ideal factors.

Simulation result:

Fig. 3 has provided the errored bit curve of the tape sort Turbo Enhancement Method MMSE equilibrium of adopting the MIMO-OFDM wireless communication receiver that the present invention proposes, can compare with the errored bit of common MMSE equilibrium in the existing MIMO-OFDM system that carries out not that Turbo strengthens.

As seen from Figure 3, the tape sort Turbo Enhancement Method of the MIMO-OFDM wireless communication receiver of the present invention's proposition is greatly improved than the performance of common MIMO-OFDM wireless communication receiver.2 * 10 ^-2To 2 * 10 ^-3Scope in, one of the MIMO-OFDM wireless communication receiver that the present invention proposes take turns and many wheel Turbo Enhancement Method than the performance improvement about 1 to 2dB of common MIMO-OFDM wireless communication receiver.

Claims (6)

1. the tape sort Turbo Enhancement Method of a MIMO-OFDM wireless communication receiver is characterized in that, may further comprise the steps:

(1) buffer memory MIMO-OFDM wireless communication receiver receive balanced before frequency domain baseband signal R, take out the baseband signal R of buffer memory and it is carried out linear equalization, baseband signal after the equilibrium is adjudicated, obtain the information bit of each layer baseband signal component of each subchannel, and further obtain the frequency domain estimated value of each layer baseband signal component of each subchannel;

(2) calculate the ordering index of frequency domain estimated value of each layer baseband signal component of each subchannel, and sort according to the frequency domain estimated value of result of calculation to each layer baseband signal component of each subchannel;

(3) ranking results of the frequency domain estimated value of each layer baseband signal component of each subchannel that obtains according to step (2) carries out Turbo to the frequency domain estimated value of each layer baseband signal component of each subchannel successively in order and strengthens; The frequency domain estimated value of each layer baseband signal component of each subchannel of baseband signal all once strengthened to be called take turns Turbo and strengthen, according to the requirement to receiver performance and complexity aspect, carry out taking turns Turbo at least and strengthen;

In the described step (3), it is as follows successively the frequency domain estimated value of each layer baseband signal component of each subchannel to be carried out taking turns the concrete grammar that Turbo strengthens in order:

Obtain arranging vector according to step (2) At first handle the 0th subchannel, the frequency domain estimated value that obtains from step (1)

In, the frequency domain estimated value of taking out the 0th subchannel S ₁The frequency domain estimated value of other each layer signal components beyond the layer is used for the s that the reconstruct receiver receives ₁The frequency-region signal that other each layers beyond the layer transmit, wherein,

Be the transmit reconstruct of component of the i layer of the 0th subchannel that receiver is received, () ^TThe transposition of representing matrix or vector;

Be the 0th subchannel that receiver is received except transmit other N the component of i layer _TThe reconstruct of-1 layer of component that transmits; Take out the balanced preceding frequency domain baseband signal of buffer memory then

Deduct the s that removes of the 0th subchannel with the signal of buffer memory ₁Layer other N beyond the component that transmits _TThe reconstruction signal of-1 layer of component that transmits, namely

With the signal that obtains

Premultiplication

Obtain

And adjudicate, obtain the s of the 0th subchannel ₁The layer signal component

Here, C is N * N _TDimension judgement output matrix,

Represent k row vector,

Expression

I component; Will

Again carry out sign map by transmitting terminal sign map mode, upgrade former frequency domain estimated value with current mapping signal

In

Handle the s of the 0th subchannel with identical method ₂The layer signal component, until

The layer signal component, the current subchannel that each reconstruct receiver receives transmit during component the frequency domain estimated value of use latest update when other layers beyond the anterior layer

This moment, the 0th subchannel Turbo enhancing finished; Handle the 1st subchannel with identical method, until the N-1 subchannel; Wherein: N is counting of FFT, N _TThe expression number of transmit antennas,

Be the channel matrix of the 0th subchannel, () _iI column vector of representing matrix or i the vectorial component of going,

Representing matrix

Generalized inverse,

The ordering matrix of representing the i layer signal component of k subchannel.

2. according to the tape sort Turbo Enhancement Method of the described MIMO-OFDM wireless communication receiver of claim 1, it is characterized in that: the method for frequency domain estimated value that obtains each layer baseband signal component of each subchannel in the described step (1) is that the baseband signal after the equilibrium is adjudicated, obtain the information bit of each subchannel, the method that the baseband signal after the equilibrium is adjudicated is identical with the method for common MIMO-OFDM wireless communication receiver; Information bit to each subchannel after the judgement carries out sign map again by transmitting terminal sign map mode, obtains the frequency domain estimated value of each layer baseband signal component of each subchannel

N is counting of FFT.

3. according to the tape sort Turbo Enhancement Method of the described MIMO-OFDM wireless communication receiver of claim 1, it is characterized in that: in the described step (2), the method for ordering index of frequency domain estimated value of each layer baseband signal component of calculating each subchannel is as follows:

When adopting the ZF equalizer, for k subchannel, after the ordering index of the frequency domain estimated value of each layer baseband signal component is the equilibrium of each layer signal component of current subchannel Wherein, the ordering index of the frequency domain estimated value of the i layer signal component of k subchannel is K ∈ (0,1 ..., N-1), i ∈ (1,2 ..., N _T), () ⁱI row vector of representing matrix;

When adopting the MMSE equalizer, for k subchannel, after the ordering index of the frequency domain estimated value of each layer baseband signal component is the equilibrium of each layer signal component of current subchannel

Perhaps balanced back noise suppressed coefficient For k subchannel, SINR after adopting equilibrium ^kThe time, the ordering index of the frequency domain estimated value of the i layer signal component of k subchannel is

I ∈ (1,2 ..., N _T), k ∈ (0,1 ..., N-1), () _iI column vector of representing matrix; For k subchannel; NS after adopting equilibrium ⁱThe time, the ordering index of the frequency domain estimated value of the i layer signal of k subchannel is

Diag wherein _iI the diagonal element of () representing matrix (); When using balanced back noise suppressed coefficient to sort index, for k subchannel, if order

Then

To calculate

The time G that uses ^kThe result store, be used for calculating balanced back noise suppressed coefficient, to reduce amount of calculation and the complexity of system; Wherein: N _TThe expression number of transmit antennas, N _RExpression reception antenna number, Be the channel matrix of k subchannel,

Be the balanced matrix of MMSE equilibrium, It is channel matrix

Generalized inverse,

Be noise variance, E _sThe average transmit power of representing each emission symbol, () ^HExpression conjugate transpose, SNR are represented balanced back signal to noise ratio, and SINR represents balanced back signal interference noise power ratio.

4. according to the tape sort Turbo Enhancement Method of the described MIMO-OFDM wireless communication receiver of claim 1, it is characterized in that: in the step (2), sort as follows according to result of calculation to the frequency domain estimated value of each layer baseband signal component of each subchannel:

For k subchannel, to signal to noise ratio snr after the equilibrium ^kOr balanced back signal interference noise power compares SINR ^kOr balanced back noise suppressed coefficient NS ^kCarry out ascending arrangement, obtain 1 * N _TDimension ordering matrix Wherein,

For SNR ^k, SINR ^kAnd NS ^kSatisfy respectively

Perhaps

Perhaps

Wherein: N _TThe expression number of transmit antennas,

The ordering matrix of representing the i layer signal component of k subchannel.

5. according to the tape sort Turbo Enhancement Method of the described MIMO-OFDM wireless communication receiver of claim 1, it is characterized in that: in the described step (3), it is as follows successively the frequency domain estimated value of each layer baseband signal component of each subchannel to be carried out the concrete grammar that many wheel Turbo strengthen in order:

The wheel that maximum Turbo enhancing is set is counted T, the value of T can arrange voluntarily according to performance and complexity needs, one takes turns after Turbo strengthens, whether the result was identical with Turbo enhancing back result before relatively Turbo strengthened, if it is inequality, carry out next round Turbo and strengthen, strengthen result and current Turbo until previous round Turbo and strengthen to come to the same thing or reach the maximum that Turbo strengthens wheel number T is set, take turns Turbo more and strengthen end.

6. according to the tape sort Turbo Enhancement Method of the described MIMO-OFDM wireless communication receiver of claim 5, it is characterized in that: it is 2≤T≤N that the wheel that described maximum Turbo strengthens is counted T _T+ 2 * log ₂(M), N here _TBe number of transmit antennas, M is-symbol mapping system number.

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