CN100471100C

CN100471100C - Multiple-in and multiple-out communication method of signal asynchronous transmission

Info

Publication number: CN100471100C
Application number: CNB2005100212896A
Authority: CN
Inventors: 唐友喜; 孔婷; 赵宏志; 邵士海
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2005-07-19
Filing date: 2005-07-19
Publication date: 2009-03-18
Anticipated expiration: 2025-07-19
Also published as: CN1901434A

Abstract

This invention discloses a MIMO communication method for signal asynchronous emission characterizing that it applies a hierachical empty time code structure and an emitter delayes signals of different emission antennas and emits them asynchronously, a receiver applies an asynchronous MIMO test method to test signals, in which, the gain brought with time delay hierarchy is used by different time dealy to emission signals at the emission end and at the receiving end, the receiving hierarchy is increased by the MIMO test method to increase the link quality of the MIMO system.

Description

Multiple-input multiple-output communication method for signal asynchronous transmission

Technical Field

The invention belongs to the technical field of communication, and particularly relates to a communication method using multiple antennas in the communication technology.

Background

Existing Multiple Input Multiple Output (MIMO) communication methods are based on signal synchronous transmission. The MIMO communication method is one of the key technologies of a new generation of wireless communication system because it has good spectral efficiency, high system capacity and good communication quality.

The MIMO communication method employs a space-time coding technique, wherein the space-time codes used mainly include two categories: space Time Trellis Codes (STTC) and Space Time Block Codes (STBC) based on transmit diversity; non-transmit diversity based Layered Space Time Codes (LSTC).

The space-time trellis code is a coding mode which comprehensively considers the design of channel coding, modulation, transmit diversity and receive diversity and can provide larger coding gain, spectrum utilization rate and diversity gain. Space-time trellis codes perform well, but their decoding complexity is quite high. In particular, the decoding complexity of space-time trellis codes (measured by the number of trellis states of the decoder) grows exponentially with the transmission rate when the number of transmit antennas is fixed. In view of this, Alamouti proposes a simple two-antenna transmit diversity scheme and a simpler decoding algorithm. From the inspired theory, Tarkh et al apply the orthogonal theory to extend the scheme to transmit diversity systems with arbitrary number of transmit antennas, thereby providing space-time block codes. Space-time block codes have a much lower decoding complexity than space-time trellis codes, although the performance is reduced.

Layered space-time codes are techniques that divide source data into several parallel sub-streams, encode and modulate them independently, and are not based on transmit diversity. Foschini et al of Bell laboratories first proposes a diagonal Layered Space-Time code (D-BLAST), where transmitted information is Space-Time coded according to diagonal lines, and under an independent Rayleigh fading environment, this structure obtains a huge theoretical capacity, whose capacity increases linearly with the number of transmitting antennas, and can reach 90% of Shannon channel capacity, although D-BLAST has a good Space-Time characteristic and hierarchical structure, one of its drawbacks is too high in complexity and is not suitable for application. Horizontal layered space-time code H-BLAST (horizontal BLAST) and vertical layered space-time code V-BLAST (vertical BLAST) were subsequently proposed, although decoding of H-BLAST is simple, its space-time characteristics are poor; the V-BLAST has better performance and low decoding complexity, so the V-BLAST is widely applied. The system based on the V-BLAST structure has been experimentally verified in a laboratory, and the frequency spectrum efficiency of the system is as high as 40bit/s/Hz in an indoor slow fading environment.

The general structure and detection algorithm of a MIMO communication system based on a layered space-time code structure are described below.

A schematic diagram of a MIMO system based on a layered space-time code structure is shown in fig. 1, and is composed of a transmitter schematic diagram and a receiver schematic diagram. The transmitter includes: the device comprises a data transmitting module 1, a layered space-time coding module 2, a digital-to-analog conversion module 3, a radio frequency processing module 1 module 4 and M transmitting antennas 5, wherein the radio frequency processing module 1 module 4 comprises M radio frequency processing sub-modules, and the radio frequency processing sub-modules on different transmitting antennas can be different. The receiver includes: the device comprises N receiving antennas 6, a radio frequency processing 2 module 7, an analog-to-digital conversion module 8, a MIMO detection module 9, a layered space-time decoding module 10 and a data recovery module 11, wherein the radio frequency processing 2 module 7 comprises N radio frequency processing sub-modules, and the radio frequency processing sub-modules on different receiving antennas can be different.

The MIMO communication method based on the layered space-time code structure has many mature signal detection algorithms, such as a maximum likelihood algorithm, a zero forcing algorithm, a minimum mean square error algorithm, and the like. In the following, a zero forcing algorithm is taken as an example to introduce a signal detection algorithm of the MIMO communication method based on a layered space-time code structure.

As shown in fig. 1, a transmitted data 1 firstly passes through a layered space-time coding module 2 to code the transmitted data into parallel M-channel data symbol streams, and after passing through a wireless channel, the M-channel data symbol streams are simultaneously received by N receiving antennas at a receiving end, and a received signal is subjected to zero forcing detection, and finally the data is output.

The equivalent baseband transmit signal M-dimensional vector we define as a ═ (a)₁ a₂ … a_M)^T，a_kRepresenting data for the kth transmit antenna, the corresponding received signal vector is r ═ (r)₁ r₂ ... r_N)^TCan be represented as

r＝Ha+N (1)

Wherein

h_i，jRepresenting the channel fading factor from the jth transmit antenna to the ith receive antenna, assuming different h_ijIndependent of each other, N represents the gaussian noise vector at the receiving end. The direct inversion zero-forcing detection method is expressed as follows, and the estimated value of the transmitted signal vectorIs composed of

Wherein,

represents the Moore-Penrose inverse of the matrix. The principle of the method is that the inversion operation is directly carried out on a channel matrix, then the inverse matrix is used for left-multiplying a received signal vector, and then all components are decoded simultaneously. Details are given in G.D.golden, C.J.Foschini, "Detection of the same and initial laboratory using V-BLAST space-time communication architecture", IEEETRONICS LETTERS7^th Jan 1999，Vol.35 No.1.

The existing mimo communication methods are all based on signal synchronous transmission. For the mimo communication method using layered space-time codes, since signals are transmitted simultaneously at the transmitting end, the transmitting end does not have the gain caused by delay diversity, and the receiving diversity degree of the receiving end is low, thereby affecting the link quality and the system capacity. In view of the disadvantages of the existing mimo communication methods, no existing document, patent and related publications provide a mimo communication method for asynchronous signal transmission.

Disclosure of Invention

The invention aims to provide a MIMO communication method for signal asynchronous transmission, aiming at the defects of the existing MIMO communication method for signal synchronous transmission.

For convenience of describing the contents of the present invention, an explanation will be first made on the following terms, as shown in fig. 2 and 3:

1) layered space-time coding technique: performing layered space-time coding modulation on input data to form a plurality of paths of data symbol streams for output;

2) the framing technology comprises the following steps: the method comprises the steps of combining an input data symbol stream into a plurality of data frames with certain length and outputting the data frames;

3) the time delay technology comprises the following steps: the method comprises the steps of delaying an input data frame with a certain length for a period of time and then outputting the delayed data frame;

4) guard interval addition technique: the method is characterized in that a guard interval with a certain time length is added at the tail of an input data frame, so as to avoid interference between frames;

5) matched filtering technology: the method comprises the steps of matching signals on different transmitting antennas so as to distinguish the signals on the different transmitting antennas;

6) data sampling technique: sampling an input signal, and outputting discrete sampling values at different moments;

7) layered space-time decoding technique: and carrying out layered space-time decoding demodulation on the input data to obtain recovered data.

The layered space-time coding technique may be a V-BLAST coding technique, or a H-BLAST coding technique or a D-BLAST coding technique.

The layered space-time decoding technique may be a V-BLAST decoding technique, or a H-BLAST decoding technique or a D-BLAST decoding technique.

The invention provides a multiple-input multiple-output communication method for signal asynchronous transmission, which comprises a transmitting step and a receiving step:

a transmitter of a mimo communication method for asynchronous signal transmission has M (M is a positive integer) transmitting antennas (as shown in fig. 2 and 5), and the transmitting step includes:

step 1: layered space-time coding

Coding input transmitting data 1 into M paths of parallel data symbol streams by adopting a layered space-time coding technology and outputting the data symbol streams;

step 2: framing

Adopting framing technique to make M channels of data symbol stream output from step 1 respectively form several data with a certain lengthAnd (5) outputting the frame. The length of each data frame is equal, the length of the data frame is more than or equal to 2, and the length of the data frame is determined by factors such as the complexity requirement of a receiver in engineering, the error rate performance requirement of a system and the like. The concrete expression is as follows: let the ith data symbol on the kth antenna be b_k(i) Where k is 1, …, M, the length of the data frame is S, i.e. it contains S data symbols, and S ≧ 2. In the framing step, each path of data symbols is combined into a plurality of data frames with the length of S and output, and one data frame corresponding to the kth path of data symbols comprises S symbols, namely b_k(0)，b_k(1)，…，b_k(S-1)；

And step 3: time delay

Adopting time delay technique to make time delay for every data frame on M channels outputted from step 2, setting delay time of data frame on k-th transmitting antenna as tau_kThe data frame on the k-th path is delayed by tau_kWhere k is 1, …, M. Requiring a delay time tau per frame of data_kLess than a number of symbol periods, i.e. 0 ≦ τ_k<ΔT_s(Δ is a positive integer greater than 0); time delay tau on different branches_kMay be unequal, or partially unequal, and there is a set of optimal time delays τ₁，τ₂，…，τ_MOptimizing the system error rate performance; tau in engineering_kThe size is determined by factors such as the utilization rate of a system frequency spectrum, the requirement of the system error rate performance and the like;

and 4, step 4: adding guard intervals

And (3) adding a guard interval with a certain time length to the tail part of each data frame output in the step (3) by adopting a guard interval adding technology. The guard interval may be set to zero, or other data that may avoid frame-to-frame interference may be placed. The time length of the engineering protection interval is determined by the delay time of each path of data and the spectrum utilization rate of the system. Suppose that path k has been delayed by τ_kAfter the data frame, the increased time length is T_gkGuard interval of, requirement τ_k+T_gk＝τ_m+T_gmK, M ∈ {1, 2, …, M }, as shown in FIG. 4Taking a frame of data on each antenna as an example, let 0 ≦ τ₁<τ₂<…<τ_M<T_sTo eliminate frame-to-frame interference, the guard interval on the kth transmitting antenna needs to satisfy T_gk≥τ_M-τ_kSo the minimum guard interval on the mth transmit antenna may be zero;

and 5: digital to analog conversion

Converting the M paths of digital signals output by the step 4 into M paths of analog signals to be output;

step 6: transmit radio frequency processing

And (5) performing radio frequency processing on the M paths of analog signals output by the step (5) to obtain M paths of signals meeting the transmission requirement, and transmitting the signals from M transmitting antennas.

Taking a frame of data as an example on each transmitting antenna, adopting a method of setting zero in a guard interval, and after steps 1, 2, 3 and 4, obtaining a low-pass equivalent complex baseband signal corresponding to a transmitting antenna k can be expressed as:

wherein, b_k(i) For a symbol transmitted in the ith symbol duration corresponding to the kth transmit antenna, bk (i) 0,

<math> <mrow> <mi>i</mi> <mo>&NotElement;</mo> <mrow> <mo>{</mo> <mn>0,1</mn> <mo>,</mo> <mo>·</mo> <mo>·</mo> <mo>·</mo> <mo>,</mo> <mi>S</mi> <mo>-</mo> <mn>1</mn> <mo>}</mo> </mrow> <mo>;</mo> </mrow></math>

E_sfor the symbol energy, the transmission antennas in equation (4) are represented in the form of an average power distribution, and the transmission power of each transmission antenna is

T_sIs data b_k(i) A period of one symbol; g (t) is an equivalent complex baseband waveform of a transmitting antenna, and g (t) satisfies: (g), (t) is 0, and (g),

<math> <mrow> <mi>t</mi> <mo>&NotElement;</mo> <mrow> <mo>[</mo> <mn>0</mn> <mo>,</mo> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>)</mo> </mrow> <mo>,</mo> </mrow></math>

<math> <mrow> <msup> <mrow> <mo>|</mo> <mo>|</mo> <mi>g</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mo>|</mo> <mo>|</mo> </mrow> <mn>2</mn> </msup> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mn>0</mn> <msub> <mi>T</mi> <mi>s</mi> </msub> </msubsup> <mi>g</mi> <mo>*</mo> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>g</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>dt</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> </mrow></math>

wherein the superscript is^*Representing a complex conjugate.

Assuming that a receiver of a mimo communication method for asynchronous signal transmission has N (N is a positive integer) receiving antennas (as shown in fig. 3 and 6), the receiving step includes:

and 7: receive radio frequency processing

After the signals received by the receiving antenna 6 are processed by receiving radio frequency, N baseband signals r are obtained_j(t), j ═ 1, …, N; as shown in fig. 3, the j-th receiving antenna 6 of the receiver receives the signal r after the rf processing step 7_j(t) is:

wherein h is_j，k(i) Channel fading factor, n, from the kth transmit antenna to the jth receive antenna at time i_j(t) is the additive complex white gaussian noise on the jth receive antenna.

And 8: matched filtering

For N baseband signals r output in step 7_j(t), j is 1, …, N, and the baseband signal r on the jth receiving antenna is matched as shown in fig. 3_jAnd (t) outputting M paths of signals through M matched filters. Similarly, the baseband signals on the N receiving antennas respectively pass through the M matched filters to obtain M × N signals. This procedure is represented as follows: received signal r_j(t) the output at time l after passing through the matched filter of transmitting antenna M (positive integer m.ltoreq.M.ltoreq.1) is

<math> <mrow> <mfenced open='' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>y</mi> <mi>j</mi> <mi>m</mi> </msubsup> <mrow> <mo>(</mo> <mi>l</mi> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <msub> <mi>r</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> </mtd> <mtd> <mi>m</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mo>·</mo> <mo>·</mo> <mo>·</mo> <mi>M</mi> </mtd> </mtr> </mtable> </mfenced> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>6</mn> <mo>)</mo> </mrow> </mrow></math>

Substituting formula (5) into formula (6) to yield:

<math> <mfenced open='' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>y</mi> <mi>j</mi> <mi>m</mi> </msubsup> <mrow> <mo>(</mo> <mi>l</mi> <mo>)</mo> </mrow> <mo>=</mo> <msqrt> <mfrac> <msub> <mi>E</mi> <mi>s</mi> </msub> <mi>M</mi> </mfrac> </msqrt> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>s</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <munderover> <mi>Σ</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <msub> <mi>h</mi> <mrow> <mi>j</mi> <mo>,</mo> <mi>k</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>i</mi> <mo>)</mo> </mrow> <msub> <mi>b</mi> <mi>k</mi> </msub> <mrow> <mo>(</mo> <mi>i</mi> <mo>)</mo> </mrow> <msubsup> <mo>&Integral;</mo> <mrow> <mi>l</mi> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <mi>g</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>iT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>k</mi> </msub> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>7</mn> <mo>)</mo> </mrow> </mtd> </mtr> </mtable> </mfenced></math>

<math> <mfenced open='' close=''> <mtable> <mtr> <mtd> <mo>+</mo> <msubsup> <mo>&Integral;</mo> <mrow> <mi>l</mi> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <msup> <mrow> <msub> <mi>n</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <mi>g</mi> </mrow> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> </mtd> </mtr> </mtable> </mfenced></math>

is provided with

<math> <mfenced open='' close=''> <mtable> <mtr> <mtd> <msub> <mi>R</mi> <mrow> <mi>m</mi> <mo>,</mo> <mi>k</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>l</mi> <mo>-</mo> <mi>i</mi> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <mi>g</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>iT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>k</mi> </msub> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>8</mn> <mo>)</mo> </mrow> </mtd> </mtr> </mtable> </mfenced></math>

<math> <mfenced open='' close=''> <mtable> <mtr> <mtd> <msubsup> <mi>n</mi> <mi>j</mi> <mi>m</mi> </msubsup> <mrow> <mo>(</mo> <mi>l</mi> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mrow> <mi>l</mi> <mi>T</mi> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mi>T</mi> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <msub> <mi>n</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <mi>lT</mi> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>9</mn> <mo>)</mo> </mrow> </mtd> </mtr> </mtable> </mfenced></math>

Then equation (7) can be simplified to

And step 9: data sampling

And (3) continuously sampling the signal output by the matched filter in the step (8) at the time t by adopting a data sampling technology to obtain a plurality of discrete sampling values. The steps are represented as: the output signal for the mth matched filter is T + τ at T ═ (l +1)_m(l＝0，…，S-1，τ_mTime delay of signal on mth transmitting antenna) to obtain S sampling values

M is 1, …, M, j is 1, …, N, and the signals on different receiving antennas have different sampling values obtained by data sampling.

Step 10: asynchronous MIMO detection

Firstly, the sampling obtained in the data sampling step 9 on the jth receiving antennaSample value

(M1, …, M, j 1, …, N, l 0, …, S-1) to obtain a corresponding matrix expression, which is specifically expressed as follows:

introduction of M_T×M_TOf the channel correlation matrix R (l-i) having the elements R_m，k(l-i). R (l-i) satisfies:

R(l-i)＝R^H(i-l) (11)

wherein (·)^HRepresenting a complex conjugate transpose.

From the list of values of g (t) 0,

<math> <mrow> <mi>t</mi> <mo>&NotElement;</mo> <mrow> <mo>[</mo> <mn>0</mn> <mo>,</mo> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>)</mo> </mrow> </mrow></math>

and 0 is not less than tau_k<ΔT_s，

R(l-i)＝0，|l-i|>Δ (12)

Let the diagonal channel matrix of the jth receiving antenna in the corresponding time slot of the ith symbol be

h_j(l)＝diag{h_j，1(l)，h_j，2(l)，…，h_j，M(l)} (13)

The output equation (10) of the jth receive antenna matched filter bank at time when l is 0, 1, …, S-1 can be expressed in a vector form

Wherein

b(i)＝(b₁(i)，b₂(i)，…，b_M(i))^T，

Equation (14) is shown below in a more compact matrix form. Definition of

H_j＝diag{h_j(0)，h_j(1)，…，h_j(S-1)} (16)

b＝(b^T(0)，b^T(1)，…，b^T(S-1))^T (18)

Is SM_T×SM_TBlock symmetric Toeplitz matrix of (1), H_jIs SM_T×SM_TA diagonal matrix. Thus, the signal Y is extracted by matched filtering on the receiving antenna j from the symbol time slot 0 to S-1_jCan be expressed as:

sample values on the jth receiving antenna of the above equation

(M1, …, M, j 1, …, N, l 0, …, S-1) are combined. Similarly, N different matrix expressions can be obtained by performing data combination on the sampling values obtained in the data sampling step 9 on the N receiving antennas.

Then, the N matrix expressions are combined with the maximum ratio, which is specifically expressed as follows:

maximum ratio combination is carried out on matrix expressions corresponding to N different receiving antennas to obtain a combined matrix expression of the N receiving antennas

(21)

Is provided with The above formula can be changed into

Y = \sqrt{\frac{E_{s}}{M}} Hb + N - - - (22)

Finally, based on the joint matrix expression (22) of N receiving antennas, the estimated value of the code element symbol b can be recovered by using the methods of direct Zero-Forcing (ZF), ordering interference cancellation and the like

Any other estimate can be recovered

The detection method of (3) is also applicable to the detection step of the present invention.

Step 11: layered space-time decoding

Adopting a layered space-time decoding technology to obtain an estimated value of the code element symbol obtained in the step 10

And decoding to obtain recovered data.

After the steps, the MIMO communication method for signal asynchronous transmission provided by the invention can be realized.

It should be noted that:

the M data symbol streams in step 1 correspond to M transmitting antennas;

in step 5, the radio frequency processing procedures corresponding to different transmitting antennas can be different;

the purpose of the received rf processing in step 7 is to make the signal r_j(t) can meet the processing requirements of the subsequent stage circuit;

in step 7, the radio frequency processing procedures corresponding to different receiving antennas can be different;

the working process of the invention is as follows:

as shown in fig. 2 and fig. 3, the transmitted data is first encoded by the layered space-time coding module 2 to obtain M data symbol streams; then, the M paths of data symbol streams form a plurality of data frames with the length of S through the framing module 12; each path of data frame is delayed by a submodule in the delay module 13; each path of delayed data frame is added with respective guard interval after the data frame by the guard interval adding module 14; and then the processed data frame is transmitted from the transmitting antenna after passing through the digital-to-analog conversion module 3 and the radio frequency processing module 3 15. After receiving the signals, the receiving antenna 6 obtains N received signals r through the radio frequency processing 4 module 16_j(t), j ═ 1, …, N, received signal r_j(t) matching and filtering the transmitting signals on different antennas by a matching filter bank module 17, sampling the matched signals by a data sampling module 18 to obtain a group of sampling values

M is 1, …, M, j is 1, …, N, and the signals on different receiving antennas have different sampled values obtained by the data sampling module 18. The sampling value output by the data sampling module 18 is input into the asynchronous MIMO detection module, the sampling value on the jth receiving antenna is firstly combined into a matrix expression form, and then the matrix expressions on different receiving antennas are subjected to maximum ratioAnd combining, then obtaining an estimated value of the code element symbol, and finally obtaining recovered data through layered space-time decoding.

The innovation of the invention is as follows: in the existing multiple input multiple output communication method, signals are transmitted synchronously, and a MIMO detection method is adopted to recover the transmitted signals. The invention provides a multiple-input multiple-output communication method for signal asynchronous transmission, which leads the transmission signal to be transmitted asynchronously by carrying out different time delays on the transmission signal, and recovers the transmission signal at a receiving end by adopting a corresponding asynchronous MIMO detection method. The asynchronous transmission of the signal at the transmitting end utilizes the time delay diversity, the asynchronous MIMO detection algorithm at the receiving end increases the receiving diversity degree, the link quality of a multi-input multi-output system can be improved, the error rate is reduced, and the system performance is improved.

The essence of the invention is as follows: the invention provides a MIMO communication method for signal asynchronous transmission, which is characterized in that a layered space-time code structure is adopted, a transmitter asynchronously transmits signals on different transmitting antennas after delaying the signals, and a receiver detects the signals by adopting an asynchronous MIMO detection method. The transmitting end utilizes the gain brought by delay diversity by carrying out different delays on the transmitted signals; the asynchronous MIMO detection algorithm is adopted at the receiving end, so that the receiving diversity degree is increased, the link quality of a multi-input multi-output system can be improved, the error rate is reduced, and the system performance is improved.

The invention has the advantages that: the MIMO communication method for signal asynchronous transmission provided by the invention introduces delay diversity on the basis of keeping high frequency spectrum utilization rate and large system capacity of the existing MIMO communication method adopting layered space-time codes, increases the receiving diversity degree, further reduces the error rate, and can improve the link quality and the overall system performance.

In summary, the mimo communication method for asynchronous signal transmission provided by the present invention performs time delay on signals on different transmitting antennas at a transmitting end, so that the signals are transmitted asynchronously; and recovering the signal by adopting an asynchronous MIMO detection method at the receiver. Delay diversity is introduced by the transmitting terminal to different time delays of signals on different transmitting antennas, the receiving diversity degree is increased by an asynchronous MIMO detection algorithm of the receiving terminal, the link quality of a multi-input multi-output system can be improved, the error rate is reduced, and the system performance is improved.

Drawings

FIG. 1 is a schematic diagram of a conventional MIMO system based on a layered space-time code structure

Wherein, 1 is a transmitting data module, 2 is a layered space-time coding module, 3 is a digital-to-analog conversion module, 4 is a radio frequency processing 1 module, 4, 5 is a transmitting antenna, 6 is a receiving antenna, 7 is a radio frequency processing 2 module, 8 is an analog-to-digital conversion module, 9 is a MIMO detection module, 10 is a layered space-time decoding module, 11 is a data recovery module, TX 1 represents a transmitting antenna 1, TX k represents a transmitting antenna k, TX M represents a transmitting antenna M, RX 1 represents a receiving antenna 1, RX k represents a receiving antenna k, RX N represents a receiving antenna N, D/a represents digital-to-analog conversion, a/D represents analog-to-digital conversion, radio frequency 1_1 represents the 1 st sub-module of the radio frequency processing 1 module, radio frequency 1_ k represents the kth sub-module of the radio frequency processing 1 module, and radio frequency 1_ M represents the mth sub-module of the radio frequency, the radio frequency 2_1 represents the 1 st sub-module of the radio frequency processing 2 module, the radio frequency 2_ k represents the kth sub-module of the radio frequency processing 2 module, and the radio frequency 2_ N represents the nth sub-module of the radio frequency processing 2 module. FIG. 2 is a schematic diagram of a transmitter of the MIMO communication method for asynchronously transmitting signals according to the present invention

Wherein, 1 is a data transmitting module, 2 is a layered space-time coding module, 12 is a framing module, 13 is a time delay module, 14 is a module for adding a guard interval, 3 is a digital-to-analog conversion module, 15 is a radio frequency processing 3 module, 5 is a transmitting antenna, TX 1 represents a transmitting antenna 1, TX k represents a transmitting antenna k, TX M represents a transmitting antenna M, D/A represents digital-to-analog conversion, tau is a transmitting antenna₁Representing the delay, τ, of the signal on the 1 st transmitting antenna_kRepresenting the delay, τ, of the signal on the kth transmit antenna_MRepresenting the delay of the signal on the Mth transmitting antenna, the radio frequency 3_1 represents the 1 st sub-module of the radio frequency processing 3 module, and the radio frequency 3_ k represents the kth sub-module of the radio frequency processing 3 moduleSub-module, rf 3_ M represents the mth sub-module of the rf processing 3 module.

FIG. 3 is a schematic diagram of a receiver of the MIMO communication method for asynchronously transmitting signals according to the present invention

Wherein 6 is a receiving antenna, 16 is a radio frequency processing 4 module, 17 is a matched filter bank module, 18 is a data sampling module, 19 is an asynchronous MIMO detection module, 10 is a layered space-time decoding module, 11 is a data recovery module, r is₁(t) represents the signal obtained after radio frequency processing on the 1 st receiving antenna, r_N(t) represents the signal obtained after radio frequency processing on the 1 st receiving antenna,

(M-1, …, M, j-1, …, N, l-0, …, S-1) represents the sampling at time l after the signal on the jth receiving antenna passes through the transmitting antenna M-matched filter, T-1T + τ_m(M-1, …, M) represents the sampling time of the signal after the matched filter of the transmitting antenna M at different time points.

FIG. 4 is a schematic diagram of an asynchronous transmit signal of the present invention

Wherein, tau_k(k-1, …, M) denotes the delay of the signal on the kth transmit antenna, T_gk(k-1, …, M) is the length of time of the guard interval added on the kth transmit antenna, b_k(i) (k 1, …, M, i 0, …, S-1) is the symbol transmitted during the ith symbol duration for the kth transmit antenna.

FIG. 5 is a schematic block diagram of the transmission flow of the MIMO communication method of the asynchronous transmission signal of the present invention

FIG. 6 is a schematic block diagram of the receiving process of the MIMO communication method of the asynchronous transmitting signal of the present invention

The specific implementation mode is as follows:

the invention provides a multiple-input multiple-output communication method for signal asynchronous transmission,the system comprises a transmitter and a receiver, as shown in fig. 2 and fig. 3. An embodiment of the method is given below, where the number of transmit antennas M is 2, the number of receive antennas N is 2, the frame length of the data frame is S2, E _s1, the average power distribution is adopted, the baseband pulse waveform adopts rectangular wave, and the time delay of transmitting antenna is tau₁＝0，τ₂＝0.6T_s，T _s1 mus, guard interval T added_g1＝0.6T_s，T_g2And 0, the data in the guard interval is zero.

Under the condition of the above parameters, the specific implementation steps of the mimo communication method for asynchronous signal transmission provided by the present invention are described as follows, and the transmitter is shown in fig. 2:

at the transmitting end, after the transmitted data passes through the layered space-time coding 2, the framing module 12, the delay module 13 and the guard interval adding module 14, the low-pass equivalent complex baseband signals on the transmitting antenna 1 and the transmitting antenna 2 can be respectively expressed as:

the signals on the transmitting antenna 1 and the transmitting antenna 2 are sent to a wireless channel after being processed by radio frequency.

As shown in FIG. 3, at the receiving end, the receiver obtains a received signal r after a radio frequency processing step₁(t) and r₂(t), expressed as follows:

after passing through the matched filter bank module 17 and the data sampling module 18, the sampling value of the mth matched filter on the receiving antenna 1 and the receiving antenna 2 at the time point l can be represented as follows:

after the sampling values of the receiving antenna 1 and the receiving antenna 2 are input into the asynchronous MIMO detection module, the matrix expressions formed by recombining the data can be respectively expressed as:

the variables of the above formula are defined as the following formulas (15) to (19). The maximum ratio combining of the signal of the receiving antenna 1 and the receiving antenna 2 can be obtained

Y = \sqrt{\frac{1}{2}} Hb + N - - - (31)

Finally, zero forcing detection is carried out to recover the estimated value of the signal

Is shown below

Estimation of a signal

The recovered data is obtained after passing through the layered space-time decoding module 10.

The embodiment of the mimo communication method for asynchronous signal transmission can be realized by adopting C language programming, and computer simulation shows that compared with the existing mimo communication method for synchronous signal transmission, the mimo communication method has the advantages of improving the link quality of a mimo system, reducing the error rate, improving the system performance and the like.

Claims

1. A multiple input multiple output communication method of signal asynchronous transmission is characterized in that it comprises a transmitting step and a receiving step;

a transmitter of a multiple-input multiple-output communication method for asynchronous signal transmission comprises M transmitting antennas, wherein M is a positive integer, and the transmitting step comprises the following steps:

step 1: layered space-time coding

The method comprises the steps that an input transmitting data (1) is coded into M paths of parallel data symbol streams and output by adopting a layered space-time coding technology, wherein the layered space-time coding technology is a vertical layered space-time code V-BLAST coding technology, a horizontal layered space-time code H-BLAST coding technology or a diagonal layered space-time code D-BLAST coding technology;

step 2: framing

Adopting a framing technology to respectively form the M paths of data symbol streams output in the step 1 into a plurality of data frames with certain length to be output; the length of each data frame is equal, the length of the data frame is more than or equal to 2, and the length of the data frame is determined by factors including the requirement of the complexity of a receiver in engineering and the requirement of the performance of the error rate of a system; the concrete expression is as follows: let the ith data symbol on the kth antenna be b_k(i) Wherein k is 1, …, M, the length of the data frame is S, that is, S data symbols are contained, and S is more than or equal to 2; in the framing step, each path of data symbols is combined into a plurality of data frames with the length of S and output, and one data frame corresponding to the kth path of data symbols comprises S symbols, namely b_k(0)，b_k(1)，…，b_k(S-1)；

And step 3: time delay

Adopting time delay technique to make time delay for every data frame on M channels outputted from step 2, setting delay time of data frame on k-th transmitting antenna as tau_kThe data frame on the k-th path is delayed by tau_kWherein k is 1, …, M; requiring a delay time tau per frame of data_kLess than a number of symbol periods, i.e. 0 ≦ τ_k<ΔT_sΔ is a positive integer greater than 0; time delay tau on different branches_kOr not equal, or partially not equal;

and 4, step 4: adding guard intervals

Adding a guard interval with a certain time length to the tail of each data frame output in the step 3 by adopting a guard interval adding technology; setting zero in the guard interval or setting other data capable of avoiding interference between frames; the time length of the engineering protection interval is determined by the delay time of each path of data and the frequency spectrum utilization requirement of the system; suppose that path k has been delayed by τ_kAfter the data frame, the increased time length is T_gkGuard interval of, requirement τ_k+T_gk＝τ_m+T_gm，k，m∈{1，2，…，M}；

And 5: digital to analog conversion

step 6: transmit radio frequency processing

Performing radio frequency processing on the M paths of analog signals output in the step 5 to obtain M paths of signals meeting the transmission requirement, and transmitting the signals from M transmitting antennas, wherein the radio frequency processing processes corresponding to different transmitting antennas can be different;

for a frame of data on each transmitting antenna, a method of setting zero in a guard interval is adopted, and after steps 1, 2, 3 and 4, a low-pass equivalent complex baseband signal corresponding to a transmitting antenna k is obtained and can be represented as:

k＝1，…，M　　　　　　(1)

wherein, b_k(i) For symbols transmitted in the ith symbol duration corresponding to the kth transmit antenna, b_k(i)＝0，

E_sFor symbol energy, the transmission antennas in equation (1) are represented in the form of an average power distribution, and the transmission power of each transmission antenna is

wherein superscript denotes complex conjugation;

a receiver of a multiple-input multiple-output communication method for asynchronous signal transmission has N receiving antennas, wherein N is a positive integer, and the receiving step comprises the following steps:

and 7: receive radio frequency processing

The signals received by the receiving antenna (6) are processed by receiving radio frequency to obtain N baseband signals r_j(t), j is 1, …, N, and the radio frequency processing procedures corresponding to different receiving antennas are different;

the j receiving antenna (6) of the receiver receives the signal r after the radio frequency processing step 7_j(t) is:

wherein h is_j，k(i) Channel fading factor, n, from the kth transmit antenna to the jth receive antenna at time i_j(t) is additive complex white gaussian noise on the jth receive antenna;

and 8: matched filtering

For N baseband signals output in step 7r_j(t), j is 1, …, N, matched filtering, the base band signal r on j receiving antenna_j(t) outputting M paths of signals through M matched filters; similarly, the baseband signals on the N receiving antennas respectively pass through the M matched filters to obtain M × N signals; this procedure is represented as follows: received signal r_j(t) the output at time l after passing through the matched filter of the transmitting antenna m is

<math> <mrow> <msubsup> <mi>y</mi> <mi>j</mi> <mi>m</mi> </msubsup> <mrow> <mo>(</mo> <mi>l</mi> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <msub> <mi>r</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> </mrow></math>

m＝1，…M　　　　　　(3)

Wherein M is a positive integer satisfying 1. ltoreq. m.ltoreq.M;

substituting formula (2) into formula (3) to obtain:

<math> <mrow> <msubsup> <mi>y</mi> <mi>j</mi> <mi>m</mi> </msubsup> <mrow> <mo>(</mo> <mi>l</mi> <mo>)</mo> </mrow> <mo>=</mo> <msqrt> <mfrac> <msub> <mi>E</mi> <mi>s</mi> </msub> <mi>M</mi> </mfrac> </msqrt> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mi>S</mi> <mo>-</mo> <mn>1</mn> </mrow> </munderover> <munderover> <mi>Σ</mi> <mrow> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <msub> <mi>h</mi> <mrow> <mi>j</mi> <mo>,</mo> <mi>k</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>i</mi> <mo>)</mo> </mrow> <msub> <mi>b</mi> <mi>k</mi> </msub> <mrow> <mo>(</mo> <mi>i</mi> <mo>)</mo> </mrow> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <mi>g</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>iT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>k</mi> </msub> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>4</mn> <mo>)</mo> </mrow> </mrow></math>

<math> <mrow> <mo>+</mo> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <msub> <mi>n</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> </mrow></math>

is provided with

<math> <mrow> <msub> <mi>R</mi> <mrow> <mi>m</mi> <mo>,</mo> <mi>k</mi> </mrow> </msub> <mrow> <mo>(</mo> <mi>l</mi> <mo>-</mo> <mi>i</mi> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <mi>g</mi> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>iT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>k</mi> </msub> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>5</mn> <mo>)</mo> </mrow> </mrow></math>

<math> <mrow> <msubsup> <mi>n</mi> <mi>j</mi> <mi>m</mi> </msubsup> <mrow> <mo>(</mo> <mi>l</mi> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mo>&Integral;</mo> <mrow> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> <mrow> <mrow> <mo>(</mo> <mi>l</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <msub> <mi>T</mi> <mi>s</mi> </msub> <mo>+</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> </mrow> </msubsup> <msub> <mi>n</mi> <mi>j</mi> </msub> <mrow> <mo>(</mo> <mi>t</mi> <mo>)</mo> </mrow> <msup> <mi>g</mi> <mo>*</mo> </msup> <mrow> <mo>(</mo> <mi>t</mi> <mo>-</mo> <msub> <mi>lT</mi> <mi>s</mi> </msub> <mo>-</mo> <msub> <mi>τ</mi> <mi>m</mi> </msub> <mo>)</mo> </mrow> <mi>dt</mi> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mn>6</mn> <mo>)</mo> </mrow> </mrow></math>

Then equation (4) can be simplified to

And step 9: data sampling

Continuously sampling the signal output by the matched filter in the step 8 at the time t by adopting a data sampling technologyObtaining a plurality of discrete sampling values; the steps are represented as: the output signal of the mth matched filter for the jth receiving antenna is T + tau (l +1) T ═ T-_mWhere l is 0, …, S-1, τ_mObtaining S sampling values for the time delay of the signal on the mth transmitting antenna

M is 1, …, M, j is 1, …, N, and the signals on different receiving antennas have different sampling values obtained by data sampling;

step 10: asynchronous MIMO detection

Firstly, the sampling value obtained by the data sampling step 9 on the jth receiving antenna is sampled

Where M is 1, …, M, j is 1, …, N, l is 0, …, and S-1, and data combination is performed to obtain a corresponding matrix expression, which is specifically expressed as follows:

introduction of M_T×M_TOf the channel correlation matrix R (l-i) having the elements R_m.k(l-i); r (l-i) satisfies:

R(l-i)＝R^H(i-l) (8)

wherein (·)^HRepresents a complex conjugate transpose;

from the list of values of g (t) 0,

and 0 is not less than tau_k<ΔT_s，

R(l-i)＝0，|l-i|>Δ (9)

h_j(l)＝diag{h_j，1(l)，h_j，2(l)，…，h_j，M(l)} (10)

The output equation (7) of the M matched filters of the jth receiving antenna at the time when l is 0, 1, … and S-1 can be expressed in a vector form

Wherein

b(i)＝(b₁(i)，b₂(i)，…，b_M(i))^T，

The formula (11) is expressed in a more concise matrix form; definition of

H_j＝diag{h_j(0)，h_j(1)，…，h_j(S-1)} (13)

b＝(b^T(0)，b^T(1)，…，b^T(S-1))^T (15)

Is SM_T×SM_TBlock symmetric Toeplitz matrix of (1), H_jIs SM_T×SM_TA diagonal matrix; matched filtering is carried out on a receiving antenna j from a symbol time slot 0 to an S-1, and an extracted signal sampling value Y is obtained_jCan be expressed as:

sample values on the jth receiving antenna of the above equation

Wherein M is 1, …, M, j is 1, …, N.l is 0, …, S-1, and a matrix expression is obtained by data combination; similarly, the sampling values obtained in the data sampling step 9 on the N receiving antennas are subjected to data combination to obtain N different matrix expressions;

(18)

Is provided with

The above formula can be changed into

Y = \sqrt{\frac{E_{s}}{M}} Hb + N - - - (19)

And finally, based on a joint matrix expression (19) of N receiving antennas, recovering the estimated value of the symbol b by using a direct Zero Forcing (ZF) method or a sequencing interference cancellation method

Step 11: layered space-time decoding

Decoding to obtain recovered data, wherein the layered space-time decoding technique is either a vertical layered space-time code V-BLAST decoding technique or a horizontal layered space-time codeH-BLAST encoding technique, or diagonal layered space-time code D-BLAST encoding technique.