CN102316071A - Signal processing method and apparatus thereof - Google Patents

Abstract

The invention discloses a signal processing method and an apparatus thereof. The method comprises the following steps: a receiving terminal receives a signal carrying a preset unification training code from a sending terminal; the receiving terminal carries out Discrete Fourier Transformation (DFT) window synchronization, frequency synchronization and subcarrier recovery on the signal according to the unification training code. According to the invention, by using the same unification training code, DFT window synchronization, frequency synchronization and subcarrier recovery of the signal of the receiving terminal are realized, thus cost of Orthogonal Frequency Division Multiplexing (OFDM) is reduced.

Description

Signal processing method and device

Technical field

The present invention relates to the communications field, in particular to a kind of signal processing method and device.

Background technology

Along with the development of whole world economy and culture life, the communications market increased the needs of bandwidth fast in recent years.At present, the 100G system is almost by commercialization, and therefore, industry has turned one's attention to Beyond 1T gradually.For Beyond 1T; In numerous candidate technologies; Polarization stepped multiplexing OFDM (the orthogonal frequency division multiplexing that is concerned with; OFDM) system (PDM-CO-OFDM) receives the favor of academia and industry day by day owing to its remarkable availability of frequency spectrum, the flexible network configuration mode of suitable employing.

See also Fig. 1, Fig. 1 shows a typical PDM-CO-OFDM system, at transmitting terminal; Need the data of transmission to go here and there earlier and change (S → P); Then, carry out sign map (Symbol Map), insert midamble code (Train Symbol) again according to the needs of modulation system.Through carrying out after inverse discrete Fourier transform (IDFT) and go here and there conversion (P → S), add Cyclic Prefix (Cycle Prefix) again exports radio frequency (RF) signal by digital to analog converter (DAC) at last.For PDM (Polarization Division Multiplexing, polarization division multiplexing) mode, the RF signal can be modulated at respectively on two polarization states, sends through optical channel again.

At receiving terminal, carry out demodulation to received signal respectively.RF signal after the demodulation is synchronous through at first carrying out the DFT window behind the DAC; Remove Cyclic Prefix (Cycle Prefix) after accomplishing synchronously; Go here and there then and change that (S → P), carry out DFT more then carries out Frequency Synchronization and subcarrier recovery according to midamble code (Train Symbol).For the PDM modulation, also need carry out the rotation of going of polarization.So far, accomplish synchronously, carry out symbol judgement (MIMO Process), (P → S) reception is accomplished in the back for process and string conversion.

This shows, for the receiving terminal of PDM-CO-OFDM system, carry out before the symbol judgement need through three grades of complicacies synchronously, be respectively: a, discrete Fourier transform (DFT) window are synchronous; B, Frequency Synchronization; C, subcarrier recover.And, for the PDM modulation, also need carry out the rotation of going of polarization.In order to carry out synchronously going rotation with polarization, comparatively effective method is to insert midamble code at transmitting terminal, and receiving terminal carries out synchronously according to known midamble code and polarization goes to rotate.In the prior art, for the DFT window synchronously, subcarrier recovers and polarization goes rotation, uses three kinds of different midamble code respectively, still, too much the midamble code of kind can increase the expense of OFDM.

To the midamble code of using too much kind in the correlation technique with carry out the DFT window synchronously, subcarrier recovers and polarization goes to rotate and the low excessively problem of the availability of frequency spectrum of the OFDM that causes does not propose effective solution at present as yet.

Summary of the invention

Main purpose of the present invention is to provide a kind of signal processing method and device, to address the above problem at least.

According to an aspect of the present invention, a kind of signal processing method is provided, has comprised: receiving terminal receives the signal that carries the unified midamble code that is provided with in advance from transmitting terminal; Receiving terminal according to unified midamble code to signal carry out respectively discrete Fourier transform DFT window synchronously, Frequency Synchronization and subcarrier recover.

Preferably, before receiving terminal receives the signal that carries the unified midamble code that is provided with in advance from transmitting terminal, comprising: transmitting terminal will be unified the data that midamble code is inserted the needs transmission; The data that transmitting terminal will insert after the unified midamble code are changed through digital to analog converter DAC; Transmitting terminal modulates the signal that is converted to after optical channel sends to receiving terminal.

Preferably, receive the unified midamble code S that carries in the signal and satisfy following formula:

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4},$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

Preferably; Receiving terminal according to unified midamble code signal is carried out respectively discrete Fourier transform DFT window synchronously, after Frequency Synchronization and subcarrier recover; Comprise: under the situation of signal, signal is carried out polarization remove rotary manipulation through polarization division multiplexing PDM modulation.

Preferably, it is synchronous that receiving terminal carries out discrete Fourier transform DFT window according to unified midamble code to signal, comprising: it is synchronous according to following formula signal to be carried out the DFT window:

$R_{d,x}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x},$

$R_{d,y}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y},$

$S_{d,x}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,x}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,x}^2\left|\right)},$

$S_{d,y}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,y}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,y}^2\left|\right)},$

$\hat{d}=\frac{\mathrm{Max}{|}_d\left({|R_{d,x}/S_{d,x}|}^2\right)+\mathrm{Max}{|}_d\left({|R_{d,y}/S_{d,y}|}^2\right)}{2},$

Wherein, [r _{M, x}, r _{M, y}] ^TM the sample value that obtains for analog to digital converter ADC sampling,

Be the sync bit that estimates, Max| _d() expression slip variable d makes that the value of expression formula is maximum.

Preferably; Receiving terminal carries out Frequency Synchronization according to unified midamble code to signal; Comprise: signal is carried out Frequency Synchronization: according to following formula wherein;

is the frequency offset estimating value, and Δ f is the ADC sample frequency.

Preferably, receiving terminal carries out subcarrier according to unified midamble code to signal and recovers, and comprising: calculate sub-carrier according to following formula:

$\left\{\begin{array}{c}{H}_{\mathrm{xx},k}=\frac{\left|\begin{array}{cc}{R}_{k,x,1}& C_{k,y,1}\\ R_{k,x,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{xy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,x,1}\\ C_{k,x,2}& R_{k,x,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yx},k}=\frac{\left|\begin{array}{cc}{R}_{k,y,1}& C_{k,y,1}\\ R_{k,y,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,y,1}\\ C_{k,x,2}& R_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\end{array}\right.,\mathrm{\Δ}=\left|\begin{array}{cc}{C}_{k,x,1}& C_{k,y,1}\\ C_{k,x,2}& C_{k,y,2}\end{array}\right|,$

$\left[\begin{array}{c}{C}_{k,x,1}\\ C_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{C}_{k,x,2}\\ C_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,1}\\ R_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,2}\\ R_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{R}_{m,x}\\ R_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

Wherein, H _{Xx, k}Be the channel frequency domain impulse response between k number of sub-carrier x transmitter and the x receiver, H _{Xy, k}Be the channel frequency domain impulse response between k number of sub-carrier x transmitter and the y receiver, H _{Yx, k}Be the channel frequency domain impulse response between k number of sub-carrier y transmitter and the x receiver, H _{Yx, k}It is the channel frequency domain impulse response between k number of sub-carrier y transmitter and the y receiver.

According to a further aspect in the invention, a kind of signal processing apparatus is provided, has comprised: receiver module is used to receive the signal that carries the unified midamble code that is provided with in advance from transmitting terminal; Processing module, be used for according to unified midamble code to signal carry out respectively discrete Fourier transform DFT window synchronously, Frequency Synchronization and subcarrier recover.

Preferably, the unified midamble code S that carries in the signal that receiver module receives satisfies following formula:

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4},$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

Preferably, this device also comprises: polarization removes rotary module, is used under the situation of signal through polarization division multiplexing PDM modulation, signal being carried out polarization removing rotary manipulation.

Through the present invention; In the PDM-CO-OFDM system; Use with a kind of midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover; Solved must use in the prior art three kinds of different midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover the problem that causes OFDM frequency deviation utilance to reduce, and then reached the effect of the frequency deviation utilance that has improved OFDM.

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:

Fig. 1 is the sketch map according to the PDM-CO-OFDM system of correlation technique;

Fig. 2 is the signal acceptance method flow chart according to the embodiment of the invention;

Fig. 3 be according to the preferred embodiment of the invention signal flow to sketch map;

Fig. 4 is that signal receives flow chart according to the preferred embodiment of the invention;

Fig. 5 is the structured flowchart according to the signal receiving device of the embodiment of the invention;

Fig. 6 is the structured flowchart of signal receiving device according to the preferred embodiment of the invention.

Embodiment

Hereinafter will and combine embodiment to specify the present invention with reference to accompanying drawing.Need to prove that under the situation of not conflicting, embodiment and the characteristic among the embodiment among the application can make up each other.

Fig. 2 is the signal acceptance method flow chart according to the embodiment of the invention, and is as shown in Figure 2, and this method mainly may further comprise the steps (step S202-step S204):

Step S202, receiving terminal receive the signal that carries the unified midamble code that is provided with in advance from transmitting terminal;

Step S204, receiving terminal according to unified midamble code to signal carry out respectively discrete Fourier transform DFT window synchronously, Frequency Synchronization and subcarrier recover.

In practical application; Before step S202; Transmitting terminal can insert the data of needs transmission with unifying midamble code, will insert the data of unifying after the midamble code again and change through digital to analog converter DAC, at last the signal that is converted to is modulated after optical channel sends to receiving terminal.

Wherein, receive the unified midamble code S that carries in the signal and need satisfy following formula:

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4}$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

In step S204, receiving terminal is carrying out discrete Fourier transform DFT window when synchronous according to unified midamble code to signal, and it is synchronous to carry out the DFT window to signal according to following formula:

$R_{d,x}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x},$

$R_{d,y}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y},$

$S_{d,x}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,x}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,x}^2\left|\right)},$

$S_{d,y}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,y}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,y}^2\left|\right)},$

$\hat{d}=\frac{\mathrm{Max}{|}_d\left({|R_{d,x}/S_{d,x}|}^2\right)+\mathrm{Max}{|}_d\left({|R_{d,y}/S_{d,y}|}^2\right)}{2},$

Wherein, [r _{M, x}, r _{M, y}] ^TM the sample value that obtains for analog to digital converter ADC sampling;

Be the sync bit that estimates; Max| _d() expression slip variable d makes that the value of expression formula is maximum.

When receiving terminal carries out Frequency Synchronization according to unified midamble code to signal; Can carry out Frequency Synchronization to signal according to following formula:

wherein;

is the frequency offset estimating value, and Δ f is the ADC sample frequency.

When receiving terminal carries out the subcarrier recovery based on unified midamble code to signal, the channel frequency domain shock response that can calculate each subcarrier based on following formula:

$\left\{\begin{array}{c}{H}_{\mathrm{xx},k}=\frac{\left|\begin{array}{cc}{R}_{k,x,1}& C_{k,y,1}\\ R_{k,x,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{xy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,x,1}\\ C_{k,x,2}& R_{k,x,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yx},k}=\frac{\left|\begin{array}{cc}{R}_{k,y,1}& C_{k,y,1}\\ R_{k,y,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,y,1}\\ C_{k,x,2}& R_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\end{array}\right.,\mathrm{\Δ}=\left|\begin{array}{cc}{C}_{k,x,1}& C_{k,y,1}\\ C_{k,x,2}& C_{k,y,2}\end{array}\right|,$

$\left[\begin{array}{c}{C}_{k,x,1}\\ C_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{C}_{k,x,2}\\ C_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,1}\\ R_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,2}\\ R_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{R}_{m,x}\\ R_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

Wherein, H _{Xx, k}Be the channel frequency domain impulse response between k number of sub-carrier x transmitter and the x receiver, H _{Xy, k}Be the channel frequency domain impulse response between k number of sub-carrier x transmitter and the y receiver, H _{Yx, k}Be the channel frequency domain impulse response between k number of sub-carrier y transmitter and the x receiver, H _{Yx, k}It is the channel frequency domain impulse response between k number of sub-carrier y transmitter and the y receiver.

In practical application, if transmitting terminal is before sending said signal, this signal has been carried out polarization division multiplexing (PDM) modulation, after step S204, receiving terminal can also carry out polarization to this signal and remove rotary manipulation.

Fig. 3 be according to the preferred embodiment of the invention signal flow to sketch map, as shown in Figure 3, after receiving terminal receives signal; At first signal is carried out demodulation, the RF signal after the demodulation is carried out DAC conversion, it is synchronous to carry out the DFT window again; After accomplishing synchronously, remove Cyclic Prefix (Cycle Prefix), then; Go here and there and change (S → P), and carry out DFT.From removing, at last signal is carried out channel estimating through unifying midamble code (Train Symbol) the signal behind the DFT.

Fig. 4 is that signal receives flow chart according to the preferred embodiment of the invention, and as shown in Figure 4, this flow process mainly comprises:

S402, it is synchronous to carry out the DFT window;

S404, according to formula M (d)=| R _{D, x}/ S _{D, x}| ²+ | R _{D, y}/ S _{D, y}| ²Judge whether to exist the maximum of M (d),, then carry out S406 if exist, otherwise, S402 carried out;

S406 is according to formula ${\hat{f}}_{\mathrm{Off}}=2\frac{\mathrm{Arg}\left(R_{\hat{d},x}\right)+\mathrm{Arg}\left(R_{\hat{d},y}\right)}{\mathrm{N\π}}\mathrm{\Δ\; f}$ Carry out Frequency Synchronization;

S408 is according to formula

$\left\{\begin{array}{c}{H}_{\mathrm{xx},k}=\frac{\left|\begin{array}{cc}{R}_{k,x,1}& C_{k,y,1}\\ R_{k,x,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{xy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,x,1}\\ C_{k,x,2}& R_{k,x,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yx},k}=\frac{\left|\begin{array}{cc}{R}_{k,y,1}& C_{k,y,1}\\ R_{k,y,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,y,1}\\ C_{k,x,2}& R_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\end{array}\right.,\mathrm{\Δ}=\left|\begin{array}{cc}{C}_{k,x,1}& C_{k,y,1}\\ C_{k,x,2}& C_{k,y,2}\end{array}\right|,$

$\left[\begin{array}{c}{C}_{k,x,1}\\ C_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right)$

$\left[\begin{array}{c}{C}_{k,x,2}\\ C_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right)$

$\left[\begin{array}{c}{R}_{k,x,1}\\ R_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right)$

$\left[\begin{array}{c}{R}_{k,x,2}\\ R_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{R}_{m,x}\\ R_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right)$

Carrying out subcarrier recovers;

In above-mentioned flow process, wherein:

Corresponding DFT window is synchronous, midamble code through satisfy behind the IDFT as below the relation of formula (1):

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4},$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

If [r _{M, x}, r _{M, y}] ^TBe m the sample value that receiving terminal ADC sampling obtains, the frequency deviation of establishing receiving terminal local oscillator and transmitting terminal carrier wave is f _Off, OFDM subcarrier spacing Δ f then receives signal shown in following formula (2):

$\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]=\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]\⊗\mathrm{Expj}\left(\frac{2\mathrm{\π}{f}_{\mathrm{Off}}m}{\mathrm{\Δ\; f}}\right)\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]---\left(2\right),$ Wherein, $\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]$ Time domain impulse response for channel.

According to before the midamble code 1/4th and second 1/4th; The 3rd 1/4th and the 4th 1/4th correlation characteristics are that the reception data of N are divided into four sections with length, and first section is carried out related operation with second section; The 3rd section and the 4th section is carried out related operation; Therefore because the data of transmission are random signal, its correlation is 0, and having only this N data is that related operation just can reach maximum under the situation of midamble code.

M(d _x)=|R _d，x/S _d，x| ²(3.1)， $R_{d,x}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x}+\underset{m=N/21}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x}---\left(3.2\right),$ $S_{d,x}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,x}^2\left|\right)}---\left(3.3\right);$

Can know by above-mentioned formula, make M (d when d changes _x) when getting maximum, just can obtain DFT window sync bit; During the dual-polarization attitude, can attack simultaneously two polarization states and get the average of two valuations then, can realize that thus the DFT window is synchronous.

For Frequency Synchronization, can know that by formula (3.2) signal is through shown in the DFT window following formula of relation (4) after synchronously:

$R_{\hat{d},x}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{\left|r_{m+\hat{d},x}\right|}^2\mathrm{Expj}(\mathrm{\θ}+\frac{f_{\mathrm{Off}}}{\mathrm{\Δ\; f}}\mathrm{\π})+\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{\left|r_{m+\hat{d}+N/2,x}\right|}^2\mathrm{Expj}(\mathrm{\θ}+\frac{f_{\mathrm{Off}}}{2\mathrm{\Δ\; f}}\mathrm{N\π})---\left(4\right);$ Can obtain frequency deviation f by formula (4) _OffEstimated value be shown in the following formula (5):

During dual-polarization attitude; Can get the average of two valuations; Thus, can realize Frequency Synchronization.

Recover for subcarrier, can know that by formula (1) midamble code that this midamble code is equivalent to before IDFT, add is following formula (6):

$\left[\begin{array}{c}{C}_{k,x,1}\\ C_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right)$

$\left[\begin{array}{c}{C}_{k,x,2}\\ C_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right)---\left(6\right),$

Wherein, [c _{K, x, 1}, c _{K, y, 1}] ^TBe loading data on the k number of sub-carrier of first OFDM midamble code symbol, [c _{K, x, 2}, c _{K, y, 2}] ^TLoading data on the k number of sub-carrier of second OFDM midamble code symbol.

After having compensated frequency deviation, receive signal and satisfy the relation of following formula (7): $\mathrm{DFT}([\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}])=\left[\begin{array}{cc}{H}_{\mathrm{Xx}}& H_{\mathrm{Xy}}\\ H_{\mathrm{Yx}}& H_{\mathrm{Yy}}\end{array}\right]\·\mathrm{DFT}([\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}])---\left(7\right);$

According to formula (7) the preceding N/2 part of N midamble code data receiving is carried out the DFT conversion respectively with back N/2 part and can obtain the data on former and later two OFDM symbols on each subcarrier:

$\left[\begin{array}{c}{R}_{k,x,1}\\ R_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,2}\\ R_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{R}_{m,x}\\ R_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

Data on each subcarrier of receiving terminal and the transmitting terminal loaded data that is prone to know are compared the impulse response that can obtain the channel frequency domain:

$\left\{\begin{array}{c}{H}_{\mathrm{xx},k}=\frac{\left|\begin{array}{cc}{R}_{k,x,1}& C_{k,y,1}\\ R_{k,x,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{xy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,x,1}\\ C_{k,x,2}& R_{k,x,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yx},k}=\frac{\left|\begin{array}{cc}{R}_{k,y,1}& C_{k,y,1}\\ R_{k,y,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,y,1}\\ C_{k,x,2}& R_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\end{array}\right.,\mathrm{\Δ}=\left|\begin{array}{cc}{C}_{k,x,1}& C_{k,y,1}\\ C_{k,x,2}& C_{k,y,2}\end{array}\right|.$

The signal acceptance method that adopts the foregoing description to provide; Through use same midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover; Solved must use in the prior art three kinds of different midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover the problem that causes OFDM frequency deviation utilance to reduce, and then reached the effect of the frequency deviation utilance that has improved OFDM.

Fig. 5 is the structured flowchart according to the signal receiving device of the embodiment of the invention, and this device is used to the signal acceptance method of realizing that the foregoing description provides, and as shown in Figure 5, this device mainly comprises: receiver module 10 and processing module 20.Wherein, receiver module 10 is used to receive the signal that carries the unified midamble code that is provided with in advance from transmitting terminal; Processing module 20 is connected to receiver module 10, be used for according to unified midamble code to signal carry out respectively discrete Fourier transform DFT window synchronously, Frequency Synchronization and subcarrier recover.

Preferably, the unified midamble code S that carries in the signal that receiver module 10 receives satisfies following formula:

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4},$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

In practical application, preferably, processing module 20 is being carried out discrete Fourier transform DFT window when synchronous according to unified midamble code to signal, and it is synchronous to carry out the DFT window to signal according to following formula:

$R_{d,x}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x},$

$R_{d,y}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y},$

$S_{d,x}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,x}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,x}^2\left|\right)},$

$S_{d,y}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,y}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,y}^2\left|\right)},$

$\hat{d}=\frac{\mathrm{Max}{|}_d\left({|R_{d,x}/S_{d,x}|}^2\right)+\mathrm{Max}{|}_d\left({|R_{d,y}/S_{d,y}|}^2\right)}{2},$ Wherein, [r _{M, x}, r _{M, y}] ^TM the sample value that obtains for analog to digital converter ADC sampling;

Be the sync bit that estimates; Max| _d() expression slip variable d makes that the value of expression formula is maximum.

Preferably; Processing module 20 is when carrying out Frequency Synchronization according to unified midamble code to signal; Can carry out Frequency Synchronization to signal according to following formula:

wherein;

is the frequency offset estimating value, and Δ f is the ADC sample frequency.

Preferably, processing module 20 is being carried out subcarrier when recovering according to unified midamble code to signal, the frequency domain impulse response that can calculate each sub-carrier channels according to following formula:

$\left\{\begin{array}{c}{H}_{\mathrm{xx},k}=\frac{\left|\begin{array}{cc}{R}_{k,x,1}& C_{k,y,1}\\ R_{k,x,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{xy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,x,1}\\ C_{k,x,2}& R_{k,x,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yx},k}=\frac{\left|\begin{array}{cc}{R}_{k,y,1}& C_{k,y,1}\\ R_{k,y,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,y,1}\\ C_{k,x,2}& R_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\end{array}\right.,\mathrm{\Δ}=\left|\begin{array}{cc}{C}_{k,x,1}& C_{k,y,1}\\ C_{k,x,2}& C_{k,y,2}\end{array}\right|,$

$\left[\begin{array}{c}{C}_{k,x,1}\\ C_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{C}_{k,x,2}\\ C_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,1}\\ R_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,2}\\ R_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{R}_{m,x}\\ R_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right).$

Fig. 6 is the structured flowchart of signal receiving device according to the preferred embodiment of the invention; As shown in Figure 6; This device can also comprise: polarization removes rotary module 30; Be connected to processing module 20, be used under the situation of signal, signal being carried out polarization removing rotary manipulation through polarization division multiplexing PDM modulation.

The signal receiving device that adopts the foregoing description to provide; Through use same midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover; Solved must use in the prior art three kinds of different midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover the problem that causes OFDM frequency deviation utilance to reduce, and then reached the effect of the frequency deviation utilance that has improved OFDM.

From above description; Can find out; The present invention has realized following technique effect: through use same midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover; Solved must use in the prior art three kinds of different midamble code to the signal of receiving terminal carry out the DFT window synchronously, Frequency Synchronization and subcarrier recover the problem that causes OFDM frequency deviation utilance to reduce, and then reached the effect of the frequency deviation utilance that has improved OFDM.

Obviously, it is apparent to those skilled in the art that above-mentioned each module of the present invention or each step can realize with the general calculation device; They can concentrate on the single calculation element; Perhaps be distributed on the network that a plurality of calculation element forms, alternatively, they can be realized with the executable program code of calculation element; Thereby; Can they be stored in the storage device and carry out, and in some cases, can carry out step shown or that describe with the order that is different from here by calculation element; Perhaps they are made into each integrated circuit modules respectively, perhaps a plurality of modules in them or step are made into the single integrated circuit module and realize.Like this, the present invention is not restricted to any specific hardware and software combination.

The above is merely the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1. a signal processing method is characterized in that, comprising:

Receiving terminal receives the signal that carries the unified midamble code that is provided with in advance from transmitting terminal;

Said receiving terminal according to said unified midamble code to said signal carry out respectively discrete Fourier transform DFT window synchronously, Frequency Synchronization and subcarrier recover.

2. method according to claim 1 is characterized in that, before receiving terminal receives the signal that carries the unified midamble code that is provided with in advance from transmitting terminal, comprising:

Said transmitting terminal needs said unified midamble code insertion the data of transmission;

The said data that said transmitting terminal will insert after the said unified midamble code are changed through digital to analog converter DAC;

Said transmitting terminal is modulated the back channel with the signal that is converted to and is sent to said receiving terminal.

3. method according to claim 2 is characterized in that, receives the said unified midamble code S that carries in the said signal and satisfies following formula:

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4},$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

4. method according to claim 3 is characterized in that, said signal is carried out discrete Fourier transform DFT window respectively according to said unified midamble code synchronously, after Frequency Synchronization and subcarrier recover, comprising at said receiving terminal:

Under the situation of said signal, said signal is carried out polarization remove rotary manipulation through polarization division multiplexing PDM modulation.

5. according to claim 3 or 4 said midamble code, it is synchronous that receiving terminal carries out discrete Fourier transform DFT window according to said unified midamble code to said signal, comprising:

It is synchronous according to following formula said signal to be carried out said DFT window:

$R_{d,x}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,x}^{*}{r}_{m+d+N/2,x},$

$R_{d,y}=\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y}+\underset{m=N/2+1}{\overset{3N/4}{\mathrm{\Σ}}}{r}_{m+d,y}^{*}{r}_{m+d+N/2,y},$

$S_{d,x}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,x}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,x}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,x}^2\left|\right)},$

$S_{d,y}=\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/4,y}^2\left|\right)}+\sqrt{\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+N/2,y}^2\left|\right)\left(\underset{m=1}{\overset{N/4}{\mathrm{\Σ}}}\right|r_{m+d+3N/4,y}^2\left|\right)},$

$\hat{d}=\frac{\mathrm{Max}{|}_d\left({|R_{d,x}/S_{d,x}|}^2\right)+\mathrm{Max}{|}_d\left({|R_{d,y}/S_{d,y}|}^2\right)}{2},$

Wherein, [r _{M, x}, r _{M, y}] ^TM the sample value that obtains for analog to digital converter ADC sampling;

Be the sync bit that estimates; Max| _d() expression slip variable d makes that the value of expression formula is maximum.

6. method according to claim 5 is characterized in that, said receiving terminal carries out Frequency Synchronization according to said unified midamble code to said signal, comprising:

According to following formula said signal is carried out said Frequency Synchronization:

wherein;

is the frequency offset estimating value, and Δ f is the ADC sample frequency.

7. according to the said midamble code of claim 3, according to said unified midamble code said signal is carried out subcarrier at receiving terminal and recovers, comprising:

Calculate sub-carrier according to following formula:

$\left\{\begin{array}{c}{H}_{\mathrm{xx},k}=\frac{\left|\begin{array}{cc}{R}_{k,x,1}& C_{k,y,1}\\ R_{k,x,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{xy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,x,1}\\ C_{k,x,2}& R_{k,x,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yx},k}=\frac{\left|\begin{array}{cc}{R}_{k,y,1}& C_{k,y,1}\\ R_{k,y,2}& C_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\\ H_{\mathrm{yy},k}=\frac{\left|\begin{array}{cc}{C}_{k,x,1}& R_{k,y,1}\\ C_{k,x,2}& R_{k,y,2}\end{array}\right|}{\mathrm{\Δ}}\end{array}\right.,\mathrm{\Δ}=\left|\begin{array}{cc}{C}_{k,x,1}& C_{k,y,1}\\ C_{k,x,2}& C_{k,y,2}\end{array}\right|,$

$\left[\begin{array}{c}{C}_{k,x,1}\\ C_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{C}_{k,x,2}\\ C_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,1}\\ R_{k,y,1}\end{array}\right]=\underset{m=1}{\overset{N/2}{\mathrm{\Σ}}}\left[\begin{array}{c}{r}_{m,x}\\ r_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

$\left[\begin{array}{c}{R}_{k,x,2}\\ R_{k,y,2}\end{array}\right]=\underset{m=N/2+1}{\overset{N}{\mathrm{\Σ}}}\left[\begin{array}{c}{R}_{m,x}\\ R_{m,y}\end{array}\right]\exp -j\left(\frac{4\mathrm{\π}}{N}(k-1)(m-1)\right),$

Wherein, H _{Xx, k}Be the channel frequency domain impulse response between k number of sub-carrier x transmitter and the x receiver, H _{Xy, k}Be the channel frequency domain impulse response between k number of sub-carrier x transmitter and the y receiver, H _{Yx, k}Be the channel frequency domain impulse response between k number of sub-carrier y transmitter and the x receiver, H _{Yy, k}It is the channel frequency domain impulse response between k number of sub-carrier y transmitter and the y receiver;

According to said sub-carrier said signal being carried out subcarrier recovers.

8. a signal processing apparatus is characterized in that, comprising:

Receiver module is used to receive the signal that carries the unified midamble code that is provided with in advance from transmitting terminal;

Processing module, be used for according to said unified midamble code to said signal carry out respectively discrete Fourier transform DFT window synchronously, Frequency Synchronization and subcarrier recover.

9. device according to claim 8 is characterized in that, the said unified midamble code S that carries in the said signal that said receiver module receives satisfies following formula:

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{m+N/4,x}\\ s_{m+N/4,y}\end{array}\right]e^{\mathrm{j\θ}},$ $1\≤m\≤\frac{N}{4},$

$\left[\begin{array}{c}{s}_{m,x}\\ s_{m,y}\end{array}\right]=\left[\begin{array}{c}{s}_{N-m,x}\\ s_{N-m,y}\end{array}\right],$ $1\≤m\≤\frac{N}{2},$ Wherein, m representes the sequence number of midamble code, and θ is be not equal to k π arbitrarily angled, and N is 2 times that the length of said unified midamble code equals sub-carrier number, and x and y are two orthogonal polarisation state.

10. according to Claim 8 or 9 described devices, it is characterized in that said device also comprises:

Polarization removes rotary module, is used under the situation of said signal through polarization division multiplexing PDM modulation, said signal being carried out polarization removing rotary manipulation.

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