CN100518151C - Evaluating device, system and method for multiple input and multple output channels - Google Patents

Abstract

The present invention discloses multiple input/output channel estimation device and implementation method. Said channel estimation device includes controller, receive data matrix generator, spin matrix generator, local reference pilot generator, and first multiplier, second multiplier; also discloses said channel estimation device adopted multiple input/output orthogonal frequency division multiplexing (ofdm) communication system. The present invention can make plurality of transmitter simultaneously transmitting pilot frequency in same carrier wave in multiple input/output orthogonal frequency division multiplexing (ofdm) system, in total available definite pilot frequency condition, raising receiver channel estimation quality.

Description

The channel estimating apparatus of multiple-input and multiple-output, system and method

Technical field

The present invention relates to channel estimating, relate to multi-I/O OFDM channel estimation method in communication system and device particularly.

Background technology

At present, single-channel estimation has had a large amount of methods to solve, and still, these methods of expansion also do not have good solution to the situation of a plurality of channels in an OFDM (OFDM) system.

For the multi-I/O OFDM communication system, prior art is normally separated pilot tone when sending pilot frequency information in time or on the frequency, under the certain situation of total patterns available pilot frequency information, compare with single input multi-output orthogonal frequency division multiplexing communication system with the single output of single input, the pilot frequency information that this transmission arranges the method for pilot tone to cause each channel to use reduces, thereby has reduced the quality of channel estimating.And transmitter is many more, and the channel estimating quality reduces just severe more.In addition, in actual communication, usually require multi-I/O OFDM communication system and the single output of single input, single input multi-output orthogonal frequency division multiplexing communication system compatibility, and the method for cutting apart pilot frequency information in time existing or the frequency makes the multi-I/O OFDM communication system be not easy to the single output of single input, single input multi-output orthogonal frequency division multiplexing communication system compatibility.

Summary of the invention

One of purpose of the present invention provides a kind of multi-input multi-ouput channel estimation unit, comprise: controller, be used for reaching a pilot tone transmission during cycle in the reception data of pilot channel estimation device, enable to receive data matrix generator, spin matrix generator and local reference pilot generator, thereby channel estimator is started working; Receive the data matrix generator, be used for output and receive data matrix; The spin matrix generator is used to export spin matrix; Local reference pilot generator is used to produce the needed local reference pilot signal of channel estimating; First multiplier is used to realize that the spin matrix premultiplication receives data matrix; Second multiplier is used to realize that the output result of local reference pilot generator and the output result of first multiplier multiply each other; The reception data matrix of wherein said reception data matrix generator output is:

$R\left[k\right]=\left(\begin{array}{cccccc}{R}_{\mathrm{0,0}}\left[k\right],& R_{\mathrm{1,0}}\left[k\right],& .& .& .& R_{N-\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right],& R_{\mathrm{1,1}}\left[k\right],& .& .& .& R_{N-\mathrm{1,1}}\left[k\right]\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ R_{0,M-1}\left[k\right],& R_{1,M-1}\left[k\right],& .& .& .& R_{N-1,M-1}\left[k\right]\end{array}\right)$

R[k] be M * N matrix, wherein R _{J, m}[k] expression receiver j reception data on k pilot frequency carrier wave of m receiving symbol in a pilot tone transmission cycle, m=0 wherein, 1 ... M-1;

The spin data matrix of described spin matrix generator output is:

$F^M=\frac{1}{M}{\left(\begin{array}{cccccc}{F}_{\mathrm{0,0}}^M,& F_{\mathrm{1,0}}^M,& .& .& .& F_{M-\mathrm{1,0}}^M\\ F_{\mathrm{0,1}}^M,& F_{\mathrm{1,1}}^M,& .& .& .& F_{M-\mathrm{1,1}}^M\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ F_{0,M-1}^M,& F_{1,M-1}^M,& .& .& .& F_{M-1,M-1}^M\end{array}\right)}^H$

Wherein, () ^HThe conjugate transpose of representing matrix.

Above-mentioned local reference pilot generator only need produce the pilot tone that any one transmitter sends.

Another object of the present invention provides a kind of multi-I/O OFDM communication system that adopts above-mentioned multi-input multi-ouput channel estimation unit, comprising: user data memory is used for the customer traffic that buffer memory need send; Data multiplexer is used for the customer traffic of serial is become parallel data flow, and is sent by different transmitters; The pilot data generator is used to produce basic pilot data; The pilot frequency multiplexing device produces the pilot data of all transmitter needs according to basic pilot data, makes each transmitter at one time, sends on the same frequency under the pilot tone situation, and the pilot channel estimation device still can carry out channel estimating to the pilot data that receives; A plurality of OFDM transmitters are used for the user data and the pilot data that receive are carried out carrier wave mapping, inverse Fourier transform, low-pass filtering, digital-to-analogue conversion, upconversion process, and the data after will being handled by antenna opening send to air traffic channel; A plurality of OFDM receivers, be used to receive data from air traffic channel, carry out down-converted, analog-to-digital conversion, low-pass filtering, Fourier transform, carrier wave inverse mapping, and the pilot data after will handling outputs to the pilot channel estimation device, user data outputs to the data demodulation multiplexer; The pilot channel estimation device is used for the channel frequency domain response of estimating pilot frequency carrier wave; The data demodulation multiplexer is revised the amplitude and the phase place of the data of reception according to pilot channel estimation device result, then, the concurrent user data flow of input is converted to serial data stream.

Above-mentioned pilot frequency multiplexing device comprises: the twiddle factor generator is used to produce the twiddle factor of each transmitter needs, and exports to multiplier; Above-mentioned pilot tone distributor, the pilot data that is used to import duplicates, and exports to multiplier; Above-mentioned multiplier is used for the input data of the input data of pilot tone distributor and twiddle factor generator are carried out multiplying, and exports to respective orthogonal frequency division multiplexing emission machine; Wherein, the pilot data of pilot tone distributor input is a complex sequences, and the twiddle factor of twiddle factor generator input is a plural number.

Another purpose of the present invention provides a kind of channel estimation methods that is used for the orthogonal FDM communication system of above-mentioned multiple-input and multiple-output, if the transmitter number of said system is M, be expressed as transmitter 0 respectively, transmitter 1 ... transmitter i...... transmitter M-1; The receiver number is N, is expressed as receiver 0 respectively, receiver 1 ... receiver j...... receiver N-1; Comprise the steps:

The first step, transmitter emission pilot tone, the pilot tone that any two different transmitters send on same pilot frequency carrier wave in a pilot tone transmission cycle is a quadrature;

Second step, when the data that receive reach a pilot tone and send the cycle, receiver sends the reception data in cycle according to a pilot tone, construct the reception data matrix R[k of k pilot frequency carrier wave correspondence], k=0,1,2...P-1 wherein P represents a pilot frequency carrier wave number in the OFDM symbol:

$R\left[k\right]=\left(\begin{array}{cccccc}{R}_{\mathrm{0,0}}\left[k\right],& R_{\mathrm{1,0}}\left[k\right],& .& .& .& R_{N-\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right],& R_{\mathrm{1,1}}\left[k\right],& .& .& .& R_{N-\mathrm{1,1}}\left[k\right]\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ R_{0,M-1}\left[k\right],& R_{1,M-1}\left[k\right],& .& .& .& R_{N-1,M-1}\left[k\right]\end{array}\right)$

R[k] be M * N matrix, wherein R _{J, m}[k] expression receiver j reception data on k pilot frequency carrier wave of m receiving symbol in a pilot tone transmission cycle, m=0 wherein, 1 ... M-1;

The 3rd step, channel estimator are according to twiddle factor F _{I, m} ^M(i=0,1 ... M-1, m=0,1 ... M-1), generate spin matrix F ^M, here, F _{I, m} ^MExpression transmitter total number is M, transmitter i (i=0,1 ... M-1) the m of a pilot frequency distribution in the cycle (m=0,1 ... the M-1) twiddle factor that individual symbol adopted:

$F^M=\frac{1}{M}{\left(\begin{array}{cccccc}{F}_{\mathrm{0,0}}^M,& F_{\mathrm{1,0}}^M,& .& .& .& F_{M-\mathrm{1,0}}^M\\ F_{\mathrm{0,1}}^M,& F_{\mathrm{1,1}}^M,& .& .& .& F_{M-\mathrm{1,1}}^M\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ F_{0,M-1}^M,& F_{1,M-1}^M,& .& .& .& F_{M-1,M-1}^M\end{array}\right)}^H$

Wherein, () ^HThe conjugate transpose of representing matrix;

The 4th step, F ^MPremultiplication receives data matrix R[k], multiply by S then _{I, m} ^*, promptly can obtain transmitter i and receiver j (channel estimation results is expressed in matrix as for j=0, the 1...N-1) channel estimating on carrier wave k:

$C\left[k\right]=\frac{S_{i,m}^{*}\left[k\right]}{{\left(F_{i,m}^M\right)}^{*}}{F}^{M}R\left[k\right]$

Wherein, S _{I, m} ^*Expression transmitter i is at the conjugation of the pilot data of m the symbol transmission of a pilot frequency distribution in the cycle, (F _{I, m} ^M) ^*Expression F _{I, m} ^MConjugation, C[k] be one M * N matrix:

$C\left[k\right]=\left(\begin{array}{cccccc}{C}_{\mathrm{0,0}}\left[k\right],& C_{\mathrm{0,1}}\left[k\right],& .& .& .& C_{0,N-1}\left[k\right]\\ C_{\mathrm{1,0}}\left[k\right],& C_{\mathrm{1,1}}\left[k\right],& .& .& .& C_{1,N-1}\left[k\right]\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ C_{M-\mathrm{1,0}}\left[k\right],& C_{M-\mathrm{1,1}}\left[k\right],& .& .& .& C_{M-1,N-1}\left[k\right]\end{array}\right)$

C wherein _{I, j}[k] is that transmitter i is to the channel estimating of receiver j on k pilot frequency carrier wave;

The 5th step, judge the whether little pilot wave number of k in P, if less than, then return second and go on foot; If be not less than, then finish.

Adopt method and apparatus provided by the invention, can make a plurality of transmitters under the multi-input multi-output orthogonal frequency division multiplexing system on identical carrier wave, send pilot tone simultaneously.Under the certain situation of total patterns available information, the method of this transmission pilot tone can guarantee that the pilot frequency information that each channel can use is identical with single input multi-output orthogonal frequency division multiplexing communication system with the single output of single input, thereby has improved the quality that receiver channel is estimated.In addition, method and apparatus provided by the invention also has to be realized simply, easily with advantages such as the output of single input list and single input multi-output orthogonal frequency division multiplexing communication system compatibilities.

Description of drawings

Fig. 1 is a multi-input multi-output orthogonal frequency division multiplexing system schematic diagram of the present invention.

Fig. 2 is the internal structure schematic diagram of the pilot frequency multiplexing device that proposes of the present invention.

Fig. 3 is the channel estimator internal structure schematic diagram that the present invention proposes.

Fig. 4 is the flow chart of channel estimation methods of the present invention.

Embodiment

For understanding the present invention in depth, the present invention is described in detail below in conjunction with drawings and the specific embodiments.

As shown in Figure 1, comprise multi-input multi-output orthogonal frequency division multiplexing system of the present invention and (be expressed as transmitter 0 respectively by user data memory 101, data multiplexer 102, pilot tone generator 103, pilot frequency multiplexing device 104, a M OFDM transmitter 105, transmitter 1, ... transmitter M-1), a N OFDM receiver 106 (is expressed as receiver 0 respectively, receiver 1 ... receiver N-1), pilot channel estimation device 107 and data demodulation multiplexer 108 form.User data memory 101 is used for the customer traffic that buffer memory need send.In multi-input multi-output orthogonal frequency division multiplexing system, the customer traffic in the user data memory 101 outputs to data multiplexer 102.The basic role of data multiplexer 102 is that the data flow of input is divided into parallel M road by one the tunnel, exports to OFDM transmitter 0 respectively, OFDM transmitter 1 ..., OFDM transmitter M-1.In order to resist the influence of noise and decline in the signal process of transmitting, it may also be encoded, interweave input traffic and processing such as modulation.If data multiplexer is encoded, interweaved and modulate data, the data demodulation multiplexer then carries out demodulation, deinterleaving and decoding to the data that receive.Pilot tone generator 103 produces the pilot data that some transmitters need in a symbol, this pilot data is output to pilot frequency multiplexing device 104.Pilot frequency multiplexing device 104 produces the pilot data that each transmitter needs, and is distributed to OFDM transmitter 0 according to the pilot data of input, OFDM transmitter 1 ..., OFDM transmitter M-1.The function of each OFDM transmitter is all identical, comprises that user data and the pilot data to receiving carries out carrier wave mapping, inverse Fourier transform, low-pass filtering, digital-to-analogue conversion, upconversion process etc.Data through these processing send to air traffic channel by antenna opening.The data that N in a multi-input multi-output orthogonal frequency division multiplexing system OFDM receiver 106 receives from air traffic channel, wherein, each receiver all receives the data from M transmitter.Generally speaking, these data are all declined and The noise.It is all identical and all comprise following process that 106 pairs of each OFDM receivers receive the processing of data: down-converted, analog-to-digital conversion, low-pass filtering, Fourier transform, carrier wave inverse mapping etc.The dateout of OFDM receiver 106 is divided into two-way: pilot data is output to pilot channel estimation device 107, and user data then is output to data demodulation multiplexer 108.Utilize the pilot data that a pilot tone transmission cycle receives, 107 couples of radiation machine i of pilot channel estimation device (i=0,1...M-1) (j=0,1...M-1) channel frequency domain response of all pilot frequency carrier waves is estimated, and the result is outputed to data demodulation multiplexer 108 to receiver j.Data demodulation multiplexer 108 is at first revised the amplitude and the phase place of the data of reception according to the output result of pilot channel estimation device 107, then, the concurrent user data flow of input is converted to serial data stream, if data have been carried out coding, modulation at transmitting terminal.108 of data demodulation multiplexers need carry out the demodulation sign indicating number to the data that receive to be handled.

As shown in Figure 2, the pilot frequency multiplexing device 104 of the present invention's proposition is made up of pilot tone distributor 201, twiddle factor generator 202, a M multiplier 203.Pilot tone distributor 201 is divided into parallel M road to the pilot data of input by one the tunnel, and exports to corresponding multiplier.Different with data multiplexer 102, the M circuit-switched data is all identical here, and identical with the data of input.Twiddle factor generator 202 is to produce the twiddle factor that each transmitter needs at each symbol, and exports to corresponding multiplier.In Fig. 2, establish total M transmitter, transmitter r (r=0,1 ... M-1) at the s in a pilot frequency distribution cycle (s=0,1 ..M-1) the pilot data S of individual symbol transmission _{R, s}Be basic pilot data, then arbitrarily transmitter i (i=0,1 ... M-1) m (j=0,1 ... M-1) pilot data S on the individual OFDM symbol _{I, m}Can be expressed as:

$S_{i,m}=\frac{F_{i,m}^M}{F_{r,s}^M}{S}_{r,s}$

In the present embodiment, transmitter 0 a pilot frequency distribution in the cycle the 0th symbol send pilot data S _0,0Be the master data sequence, and the transmission data of transmitter 0 on k pilot frequency carrier wave of 0 symbol are S _0,0[k], k=0,1...P-1, P represent a pilot frequency carrier wave number in the OFDM symbol.S then _{I, m}Can be expressed as:

$S_{i,m}=F_{i,m}^M{S}_{\mathrm{0,0}}$

F _{I, m} ^MExpression transmitter total number is M, transmitter i (i=0,1 ... M-1) the m of a pilot frequency distribution in the cycle (m=0,1 ... M-1) individual symbol twiddle factor that basic pilot data is carried out the phase place rotation, F _{I, m} ^MSatisfy following relation:

$\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{F}_{i,m}^M{\left(F_{r,m}^M\right)}^{*}=\left\{\begin{array}{c}0,i\≠r,i=\mathrm{0,1}...M-1,r=\mathrm{0,1}...M-1\\ M,i=r,i=\mathrm{0,1}...M-1,j=\mathrm{0,1}...M-1\end{array}\right.$

Wherein, (F _{R, m} ^M) ^*Expression F _{R, m} ^MConjugation.

The main effect of multiplier 203 is that the input data of the input data of pilot tone distributor and twiddle factor generator are carried out multiplying, and exports to corresponding OFDM transmitter.The just corresponding needed pilot data of OFDM transmitter of the output of each multiplier.Need to prove that multiplier 203 is a plural number from the input (twiddle factor) of twiddle factor generator, then is a complex sequences from the input (pilot data) of pilot tone distributor.

Be provided with four transmitters, pilot frequency distribution is four symbols, and the transmission data of transmitter 0 on k pilot frequency carrier wave of the 0th symbol are S _0,0[k]=1.If twiddle factor $F_{i,m}^4=e^{-j\frac{\mathrm{\πim}}{2}},$ i＝0，1，2，3；m＝0，1，2，3。Then the transmission data of transmitter i on k pilot frequency carrier wave of m symbol are $F_{i,m}^4=e^{-j\frac{\mathrm{\πim}}{2}}.$ Specific as follows transmitter pilot frequency distribution table:

Table 1

As shown in Figure 3, the pilot channel estimation device that proposes of the present invention by controller 301, receive data matrix generator 302, spin matrix generator 303, local reference pilot generator 304, first multiplier (form by multiplier a) 305 and second multiplier (multiplier b) 306.Controller 301 effects are whether control reception data matrix generator, spin matrix generator and local reference pilot generator enable.Send the cycle when the reception data of pilot channel estimation device reach a pilot tone, controller enables to receive data matrix generator, spin matrix generator and local reference pilot generator.Thereby channel estimator is started working.Receiving 302 effects of data matrix generator is that output is given multiplier a according to the matrix of the rule definition of following formula.

$R\left[k\right]=\left(\begin{array}{cccccc}{R}_{\mathrm{0,0}}\left[k\right],& R_{\mathrm{1,0}}\left[k\right],& .& .& .& R_{N-\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right],& R_{\mathrm{1,1}}\left[k\right],& .& .& .& R_{N-\mathrm{1,1}}\left[k\right]\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ R_{0,M-1}\left[k\right],& R_{1,M-1}\left[k\right],& .& .& .& R_{N-1,M-1}\left[k\right]\end{array}\right)$

Spin matrix generator 303 is that output is given multiplier a according to the matrix of the rule definition of following formula.

$F^M=\frac{1}{M}{\left(\begin{array}{cccccc}{F}_{\mathrm{0,0}}^M,& F_{\mathrm{1,0}}^M,& .& .& .& F_{M-\mathrm{1,0}}^M\\ F_{\mathrm{0,1}}^M,& F_{\mathrm{1,1}}^M,& .& .& .& F_{M-\mathrm{1,1}}^M\\ .& & & & & \\ .& & & & & \\ .& & & & & \\ F_{0,M-1}^M,& F_{1,M-1}^M,& .& .& .& F_{M-1,M-1}^M\end{array}\right)}^H$

The effect of multiplier a is to realize that the spin matrix premultiplication of spin matrix generator 303 outputs receives the reception data matrix of data matrix generator 302 outputs, and final result is exported to multiplier b.Another input of multiplier b is from local reference pilot generator 304.Local reference pilot generator 304 effects are to produce the needed local reference pilot signal of channel estimating.It is pointed out that and adopt method provided by the invention, local reference pilot generator not to need to produce the pilot tone that each transmitter sends, only the pilot tone that needs a transmitter of generation (for example transmitter 0) to send gets final product.Thereby amount of calculation and memory space have been reduced.The effect of multiplier b is to realize the output of local reference pilot generator and the output multiplication of multiplier a.The output of local here reference pilot generator is a plural number, still is that take advantage of on the right side so this multiplier need not be distinguished premultiplication.

Be example with table 1 below, provide the flow process of channel estimating in conjunction with Fig. 4.

At first, transmitter emission pilot tone, satisfying arbitrarily, two different transmitters are quadrature in the pilot tone that sends on the same pilot frequency carrier wave in a pilot tone transmission cycle; Carry out following step then:

Step 401 receives pilot data and whether reaches a pilot tone transmission cycle, reaches a pilot tone transmission cycle if receive pilot data, the channel estimation steps 402-408 below then starting.Otherwise, be in wait state till the reception pilot data reaches a pilot tone transmission cycle.

Step 402, the structure spin matrix.Utilize the described example of table 1, spin matrix F ⁴:

$F^4=\frac{1}{4}{\left(\begin{array}{cccc}1& 1& 1& 1\\ 1& e^{-j\frac{\mathrm{\π}}{2}}& -1& e^{j\frac{\mathrm{\π}}{2}}\\ 1& -1& 1& -1\\ 1& e^{j\frac{\mathrm{\π}}{2}}& -1& e^{-j\frac{\mathrm{\π}}{2}}\end{array}\right)}^H$

Step 403, loop initialization variable k, k=0;

Step 404, structure receives data matrix R[k]. suppose receiver number N=2, then receive data matrix R[k]:

$R\left[k\right]=\left(\begin{array}{cc}{R}_{\mathrm{0,0}}\left[k\right]& R_{\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right]& R_{\mathrm{1,1}}\left[k\right]\\ R_{\mathrm{0,2}}\left[k\right]& R_{\mathrm{1,2}}\left[k\right]\\ R_{\mathrm{0,3}}\left[k\right]& R_{\mathrm{1,3}}\left[k\right]\end{array}\right)$

Step 405, the spin matrix premultiplication receives data matrix.

$F^{4}R\left[k\right]=\frac{1}{4}{\left(\begin{array}{cccc}1& 1& 1& 1\\ 1& e^{-j\frac{\mathrm{\π}}{2}}& -1& e^{j\frac{\mathrm{\π}}{2}}\\ 1& -1& 1& -1\\ 1& e^{j\frac{\mathrm{\π}}{2}}& -1& e^{-j\frac{\mathrm{\π}}{2}}\end{array}\right)}^H\left(\begin{array}{cc}{R}_{\mathrm{0,0}}\left[k\right]& R_{\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right]& R_{\mathrm{1,1}}\left[k\right]\\ R_{\mathrm{0,2}}\left[k\right]& R_{\mathrm{1,2}}\left[k\right]\\ R_{\mathrm{0,3}}\left[k\right]& R_{\mathrm{1,3}}\left[k\right]\end{array}\right)$

$=\frac{1}{4}\left(\begin{array}{cc}{R}_{\mathrm{0,0}}\left[k\right]+R_{\mathrm{0,1}}\left[k\right]+R_{\mathrm{0,2}}\left[k\right]+R_{\mathrm{0,3}}\left[k\right]& R_{\mathrm{1,0}}\left[k\right]+R_{\mathrm{1,1}}\left[k\right]+R_{\mathrm{1,2}}\left[k\right]+R_{\mathrm{1,3}}\left[k\right]\\ \left(R_{\mathrm{0,0}}\right[k]-R_{\mathrm{0,2}}[k\left]\right)+j\left(R_{\mathrm{0,1}}\right[k]-R_{\mathrm{0,3}}[k\left]\right)& \left(R_{\mathrm{1,0}}\right[k]-R_{\mathrm{1,2}}[k\left]\right)+j\left(R_{\mathrm{1,1}}\right[k]-R_{\mathrm{1,3}}[k\left]\right)\\ R_{\mathrm{0,0}}\left[k\right]-R_{\mathrm{0,1}}\left[k\right]+R_{\mathrm{0,2}}\left[k\right]-R_{\mathrm{0,3}}\left[k\right]& R_{\mathrm{1,0}}\left[k\right]-R_{\mathrm{1,1}}\left[k\right]+R_{\mathrm{1,2}}\left[k\right]-R_{\mathrm{1,3}}\left[k\right]\\ \left(R_{\mathrm{0,0}}\right[k]-R_{\mathrm{0,2}}[k\left]\right)+j\left(R_{\mathrm{0,3}}\right[k]-R_{\mathrm{0,1}}[k\left]\right)& \left(R_{\mathrm{1,0}}\right[k]-R_{\mathrm{1,2}}[k\left]\right)+j\left(R_{\mathrm{1,3}}\right[k]-R_{\mathrm{1,1}}[k\left]\right)\end{array}\right)$

Step 406: obtain channel estimate matrix C[k], and output.When basic pilot data is S _0,0The time, the following matrix notation of channel estimation results then:

$C\left[k\right]=S_{\mathrm{0,0}}^{*}\left[k\right]F^{M}R\left[k\right]$

S _0,0The conjugation of [k] multiply by F ⁴R[k] promptly can obtain channel matrix C[k].Here because S _0,0[k]=1, so, F ⁴R[k] be exactly the channel estimate matrix C[k that is asked].

Step 407 makes k=k+1, prepares for handling next pilot frequency carrier wave.

Step 408: whether judge k less than P, P is the number of pilot frequency carrier wave here.If k is not less than P, then channel estimation process finishes, otherwise, turn back to step 404.

Work as twiddle factor $F_{i,m}^M=e^{-j\frac{2\mathrm{\πim}}{M}}$ The time, the spin matrix premultiplication receives data matrix can be with each row of data matrix carry out Fourier transform or fast Fourier transform replaces to receiving.

Here, F _{I, j} ^MCan also get That is: $F_{i,j}^M=e^{j\frac{2\mathrm{\πij}}{M}}.$

When M is 2 integral number power, F _{I, m} ^MCan get M * M hadamard matrix H ^MThe element H of the capable m of i row _{I, m} ^MH ^MBe defined as follows:

$H^M=\left(\begin{array}{cc}{H}^{M/2}& H^{M/2}\\ H^{M/2}& -H^{M/2}\end{array}\right),$

Wherein $H^2=\left(\begin{array}{cc}1& 1\\ 1& -1\end{array}\right).$

Claims (11)

1, a kind of multi-input multi-ouput channel estimation unit, it is characterized in that, comprise: controller, be used for reaching a pilot tone transmission during cycle in the reception data of pilot channel estimation device, enable to receive data matrix generator, spin matrix generator and local reference pilot generator, thereby channel estimator is started working; Receive the data matrix generator, be used for output and receive data matrix; The spin matrix generator is used to export spin matrix; Local reference pilot generator is used to produce the needed local reference pilot signal of channel estimating; First multiplier is used to realize that the spin matrix premultiplication receives data matrix; Second multiplier is used to realize that the output result of local reference pilot generator and the output result of first multiplier multiply each other; The reception data matrix of wherein said reception data matrix generator output is:

$R\left[k\right]=\left(\begin{array}{cccc}{R}_{\mathrm{0,0}}\left[k\right],& R_{\mathrm{1,0}}\left[k\right],& \·\·\·& R_{N-\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right],& R_{\mathrm{1,1}}\left[k\right],& \·\·\·& R_{N-\mathrm{1,1}}\left[k\right]\\ \·& & & \\ \·& & & \\ \·& & & \\ R_{0,M-1}\left[k\right],& R_{1,M-1}\left[k\right],& \·\·\·& R_{N-1,M-1}\left[k\right]\end{array}\right)$

R[k] be M * N matrix, wherein R _{J, m}[k] expression receiver j reception data on k pilot frequency carrier wave of m receiving symbol in a pilot tone transmission cycle, m=0 wherein, 1 ... M-1;

The spin data matrix of described spin matrix generator output is:

$F^M=\frac{1}{M}{\left(\begin{array}{cccc}{F}_{\mathrm{0,0}}^M,& F_{\mathrm{1,0}}^M,& \·\·\·& F_{M-\mathrm{1,0}}^M\\ F_{\mathrm{0,1}}^M,& F_{\mathrm{1,1}}^M,& \·\·\·& F_{M-\mathrm{1,1}}^M\\ \·& & & \\ \·& & & \\ \·& & & \\ F_{0,M-1}^M,& F_{1,M-1}^M,& \·\·\·& F_{M-1,M-1}^M\end{array}\right)}^H$

Wherein, () ^HThe conjugate transpose of representing matrix.

2, device according to claim 1 is characterized in that, described local reference pilot generator only need produce the pilot tone that any one transmitter sends.

3, a kind of multi-I/O OFDM communication system that adopts the described multi-input multi-ouput channel estimation unit of claim 1 is characterized in that, comprising: user data memory is used for the customer traffic that buffer memory need send; Data multiplexer is used for the customer traffic of serial is become parallel data flow, and is sent by different transmitters; The pilot data generator is used to produce basic pilot data; The pilot frequency multiplexing device produces the pilot data of all transmitter needs according to basic pilot data, makes each transmitter at one time, sends on the same frequency under the pilot tone situation, and the pilot channel estimation device still can carry out channel estimating to the pilot data that receives; A plurality of OFDM transmitters are used for the user data and the pilot data that receive are carried out carrier wave mapping, inverse Fourier transform, low-pass filtering, digital-to-analogue conversion, upconversion process, and the data after will being handled by antenna opening send to air traffic channel; A plurality of OFDM receivers, be used to receive data from air traffic channel, carry out down-converted, analog-to-digital conversion, low-pass filtering, Fourier transform, carrier wave inverse mapping, and the pilot data after will handling outputs to the pilot channel estimation device, user data outputs to the data demodulation multiplexer; The pilot channel estimation device is used for the channel frequency domain response of estimating pilot frequency carrier wave; The data demodulation multiplexer is revised the amplitude and the phase place of the data of reception according to pilot channel estimation device result, then, the concurrent user data flow of input is converted to serial data stream.

4, multi-I/O OFDM communication system according to claim 3 is characterized in that, described pilot frequency multiplexing device comprises: the twiddle factor generator is used to produce the twiddle factor of each transmitter needs, and exports to multiplier; Described pilot tone distributor is used to duplicate the pilot data of input, and exports to multiplier; Described multiplier is used for the input data of the input data of pilot tone distributor and twiddle factor generator are carried out multiplying, and exports to respective orthogonal frequency division multiplexing emission machine; Wherein, the pilot data of pilot tone distributor input is a complex sequences, and the twiddle factor of twiddle factor generator input is a plural number.

5, multi-I/O OFDM communication system according to claim 3, it is characterized in that, described data multiplexer can also be encoded, interweave and modulate data, and is corresponding, and described data demodulation multiplexer then carries out demodulation, deinterleaving and decoding to the data that receive.

6, a kind of channel estimation methods that is used for the orthogonal FDM communication system of multiple-input and multiple-output, the transmitter number of establishing described system is M, is expressed as transmitter 0 respectively, transmitter 1 ... transmitter M-1; The receiver number is N, is expressed as receiver 0 respectively, receiver 1 ... receiver N-1; It is characterized in that, comprise the steps:

The first step, transmitter emission pilot tone, the pilot tone that any two different transmitters send on same pilot frequency carrier wave in a pilot tone transmission cycle is a quadrature;

Second step, when the data that receive reach a pilot tone and send the cycle, receiver sends the reception data in cycle according to a pilot tone, construct the reception data matrix R[k of k pilot frequency carrier wave correspondence], k=0,1,2...P-1 wherein P represents a pilot frequency carrier wave number in the OFDM symbol:

$R\left[k\right]=\left(\begin{array}{cccc}{R}_{\mathrm{0,0}}\left[k\right],& R_{\mathrm{1,0}}\left[k\right],& \·\·\·& R_{N-\mathrm{1,0}}\left[k\right]\\ R_{\mathrm{0,1}}\left[k\right],& R_{\mathrm{1,1}}\left[k\right],& \·\·\·& R_{N-\mathrm{1,1}}\left[k\right]\\ \·& & & \\ \·& & & \\ \·& & & \\ R_{0,M-1}\left[k\right],& R_{1,M-1}\left[k\right],& \·\·\·& R_{N-1,M-1}\left[k\right]\end{array}\right)$

R[k] be M * N matrix, wherein R _{J, m}[k] expression receiver j reception data on k pilot frequency carrier wave of m receiving symbol in a pilot tone transmission cycle, m=0 wherein, 1 ... M-1;

The 3rd step, channel estimator are according to twiddle factor F _{I, m} ^M, here, F _{I, m} ^MExpression transmitter total number is M, transmitter i, and at m the twiddle factor that symbol adopted of a pilot frequency distribution in the cycle,

I=0 wherein, 1 ... M-1, m=0,1 ... M-1 generates spin matrix F ^M:

$F^M=\frac{1}{M}{\left(\begin{array}{cccc}{F}_{\mathrm{0,0}}^M,& F_{\mathrm{1,0}}^M,& \·\·\·& F_{M-\mathrm{1,0}}^M\\ F_{\mathrm{0,1}}^M,& F_{\mathrm{1,1}}^M,& \·\·\·& F_{M-\mathrm{1,1}}^M\\ \·& & & \\ \·& & & \\ \·& & & \\ F_{0,M-1}^M,& F_{1,M-1}^M,& \·\·\·& F_{M-1,M-1}^M\end{array}\right)}^H$

Wherein, () ^HThe conjugate transpose of representing matrix;

The 4th step, F ^MPremultiplication receives data matrix R[k], multiply by S then _{I, m} ^*, promptly can obtain transmitter i and the channel estimating of receiver j on carrier wave k, channel estimation results is expressed in matrix as:

$C\left[k\right]=\frac{S_{i,m}^{*}\left[k\right]}{{\left(F_{i,m}^M\right)}^{*}}{F}^{M}R\left[k\right]$

Wherein, S _{I, m} ^*Show the conjugation of transmitter i, (F at the pilot data of m the symbol transmission of a pilot frequency distribution in the cycle _{I, m} ^M) ^*Expression F _{I, m} ^MConjugation, C[k] be one M * N matrix:

$C\left[k\right]=\left(\begin{array}{cccc}{C}_{\mathrm{0,0}}\left[k\right],& C_{0,1}\left[k\right],& \·\·\·& C_{0,N-1}\left[k\right]\\ C_{0,1}\left[k\right],& C_{\mathrm{1,1}}\left[k\right],& \·\·\·& C_{1,N-1}\left[k\right]\\ \·& & & \\ \·& & & \\ \·& & & \\ C_{M-\mathrm{1,0}}\left[k\right],& C_{M-\mathrm{1,1}}\left[k\right],& \·\·\·& C_{M-1,N-1}\left[k\right]\end{array}\right)$

C wherein _{I, j}[k] is that transmitter i is to the channel estimating of receiver j on k pilot frequency carrier wave;

The 5th the step, whether judge k less than the pilot wave number P, as if less than, then return the first step; If be not less than, then finish.

7, method according to claim 6, it is characterized in that, the described first step is specifically: send pilot tone on identical carrier wave simultaneously, the pilot tone transmission cycle of each transmitter is a M OFDM symbol, if transmitter r, the pilot data that sends at s symbol is basic pilot data, then any transmitter i pilot data S on m OFDM symbol _{I, m}Can be expressed as:

$S_{i,m}=\frac{F_{i,m}^M}{F_{r,s}^M}{S}_{r,s}$

Wherein, i=0,1 ... M-1, m=0,1 ... M-1; R=0,1 ... M-1, s=0,1 ... M-1; F _{I, m} ^MBe the twiddle factor that is used for basic pilot data is carried out the phase place rotation, F _{I, m} ^MSatisfy following relation:

$\underset{m=0}{\overset{M-1}{\mathrm{\Σ}}}{F}_{i,m}^M{\left(F_{r,m}^M\right)}^{*}=\left\{\begin{array}{c}0,i\≠r,i=\mathrm{0,1}...M-1,r=\mathrm{0,1}...M-1\\ M,i=r,i=\mathrm{0,1}...M-1,j=\mathrm{0,1}...M-1\end{array}\right.$

Wherein, (F _{R, m} ^M) ^*Expression F _{R, m} ^MConjugation.

8, method according to claim 7 is characterized in that, described basic pilot data is that transmitter 0 is S at the pilot data that the 0th symbol sends _0,0, and the transmission data of transmitter 0 on k pilot frequency carrier wave of 0 symbol are S _0,0[k], k=0,1...P-1, P represent a pilot frequency carrier wave number in the OFDM symbol; Transmitter i pilot data S on m OFDM symbol then _{I, m}Can be expressed as:

$S_{i,m}=F_{i,m}^M{S}_{\mathrm{0,0}}$

Wherein, i=0,1 ... M-1, m=0,1 ... M-1.

9, according to claim 6 or 8 described methods, it is characterized in that, when basic pilot data is S _0,0The time, the following matrix notation of channel estimation results then:

$C\left[k\right]=S_{\mathrm{0,0}}^{*}\left[k\right]F^{M}R\left[k\right]$

Wherein, S _0,0 ^*Expression transmitter 0 is in the conjugation of the pilot data of the 0th symbol transmission.

10, method according to claim 7 is characterized in that, and is described $F_{i,j}^M=e^{-j\frac{2\mathrm{\πij}}{M}}$ Perhaps $F_{i,j}^M=e^{j\frac{2\mathrm{\πij}}{M}}.$

11, channel estimation methods according to claim 7 is characterized in that, when M is 2 integral number power, and F _{I, j} ^MCan get M * M hadamard matrix H ^MThe element H of the capable j of i row _{I, j} ^MH ^MBe defined as follows: $H^M=\left(\begin{array}{cc}{H}^{M/2}& H^{M/2}\\ H^{M/2}& -H^{M/2}\end{array}\right)$

Wherein

$H^2=\left(\begin{array}{cc}1& 1\\ 1& -1\end{array}\right).$

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