CN104022980A - OFDM (orthogonal frequency division multiplexing) system signal to interference plus noise power ratio blind estimation method and system - Google Patents

Abstract

The invention relates to an OFDM (orthogonal frequency division multiplexing) system signal to interference plus noise power ratio blind estimation method and system. The method comprises the following steps: accurately dividing a received OFDM signal into a multi-path overlapping transmitting signal, gauss background noise and pulse interference, calculating the average power of the single received multi-path signal by acquiring a self-correlation function of the quantity of separated subcarriers of a kth signal, calculating the sum of the average power of the received OFDM digital signal according to the average power of the single received multi-path signal, and finally calculating the statistics estimation of the signal to interference plus noise power ratio. By adopting the method, a relatively small number of calculation steps are used, so that the signal to interference plus noise power ratio estimation time is reduced. Moreover, the allocation of signal channel resources and the signal channel iteration decoding can be carried out according to the signal to interference plus noise power ratio estimation value, so that the transmission efficiency of the OFDM system can be improved.

Description

A kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method and system

Technical field

The present invention relates to the blind estimation technique of a kind of ofdm system Signal to Interference plus Noise Ratio.Relate in particular to ofdm system Signal to Interference plus Noise Ratio blind estimating method and system under a kind of impulse disturbances impact.

Background technology

OFDM (Orthogonal Frequency Division Multiplexing is OFDM) is as a kind of quadrature carrier modulation technique, there is the higher availability of frequency spectrum and good anti-multipath interference performance, be widely used in the 4th third-generation mobile communication (4G), power line communication (Power-Line-Communication, PLC) and various Digital Subscriber Line (Digital-Subscriber-Line, DSL) etc.OFDM modulation adopts a minute pattern for frame transmission, a sinusoidal subcarrier that OFDM frame comprises L MAQM or MPSK modulation.First OFDM is mapped as digital information multiple constellation point, carry out inverse discrete Fourier transform (IDFT) and obtain corresponding digital baseband signal, then the digital baseband signal that adds Cyclic Prefix (Cyclic Prefix, CP) after processing, D/A (D/A) is sent it into channel continuously.To in based on OFDM technical communication systematic research process, Signal to Interference plus Noise Ratio (SINR, Signal to Interference plus Noise Ratio) estimate it is an important content wherein, it is as the important indicator of weighing signal of communication quality, for the communication technologys such as power control, Dynamic Resource Allocation for Multimedia algorithm and iterative decoding provides necessary channel condition information, thereby improve ofdm system transmission performance.Noise and Interference is to affect the principal element that SINR estimates accuracy, except the background noise based on Gauss model, also there is in actual applications many non-Gaussian signals and interference, for example from nature or the artificial factors such as phase mutual interference between thunder and lightning, automobile engine, static release and communication network internal unit.These disturb generally there is burst, in short-term with strongly disturbing feature, shortly formed with large irregular pulse or the noise spike of amplitude by the duration, be referred to as impulse disturbances.The non-Gaussian feature of impulse disturbances, usually causes based on Gauss and supposes that the performance of designed SINR method of estimation significantly degenerates.When this performance degradation reaches certain degree and can not be out in the cold time, just must redesign corresponding treatment step according to the statistical property of disturbing, to improve SINR estimated performance.

Ofdm system SINR method of estimation under impulse disturbances impact can be divided into data assists and auxiliary two classes of non-data, and non-data-aided method of estimation is generally also referred to as blind estimation.Data-aided method of estimation realizes simple, but needs the about fixed sequence of timed sending, and Shortcomings in efficiency of transmission particularly, in distributed collaborative communication, sends the obstacle in training sequence existence mechanism.Blind estimating method overcomes data-aided deficiency, adopts maximal possibility estimation or cyclo-stationary analytical method to obtain the accurate estimation to SINR, occupies in actual applications main flow.Chinese patent literature " CN10225586A " discloses a kind of blind SNR estimating method based on MIMO-OFDM signal cycle smooth performance, its smooth performance based on ofdm signal, suitably choose the length of ofdm signal cyclic suffix, make the auto-correlation function of each transmitted signal have different zero points, by selecting different cycle frequencys, mimo channel is changed into a plurality of single-input single-output channels, then analyze the periodic auto-correlation function that receives signal regularity of energy distribution, theoretical in conjunction with close approximation, finally realize the blind estimation of signal to noise ratio.This technical scheme calculation procedure is comparatively complicated, make the blind estimating step of signal to noise ratio comparatively loaded down with trivial details, consuming time longer, and estimated accuracy is also weak.

Summary of the invention

For this reason, technical problem to be solved by this invention is that in prior art, the blind estimation calculation procedure of ofdm system Signal to Interference plus Noise Ratio is comparatively complicated, blind estimation is consuming time longer, and estimated accuracy is not high, thereby proposes a kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method and system based on correlation analysis.

For solving the problems of the technologies described above, technical scheme of the present invention is:

An ofdm system Signal to Interference plus Noise Ratio blind estimating method, comprises the following steps:

Receive digital signal: the OFDM digital signal by the transmitting of antenna reception OFDM transmitter, is designated as y, y by described OFDM digital signal _kfor k the OFDM digital signal receiving, the transmitted signal r that it is superposeed by multipath _k, Gaussian Background noise n _kwith impulse disturbances v _kaddition forms, i.e. y _k=r _k+ n _k+ v _k, wherein: x _kbe k transmitted signal, a _ibe the fading channel coefficient of i paths, r _kfor the stack of multipath signal, L _hexponent number for channel impulse response;

Calculate the average power of single receiving multipath signals: definition auto-correlation function, obtain the be separated by auto-correlation function of sub-carrier number L of k signal, for:

$\begin{array}{c}{R}_y(k,k+L)=E\left(y_k{y^{*}}_{k+L}\right)\\ =E\left[(r_k+n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\\ =E\left[r_k{r}_{k+L}^{*}\right]+E[r_k{n}_{k+L}^{*}+r_k{v}_{k+L}^{*}]+E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\end{array},$

Wherein, L is ofdm signal sub-carrier number, k ∈ [0, L-1], E (y _ky ^* _k+L) for receiving the arithmetic average after the conjugated signal of signal and displacement L multiplies each other; Because reception signal, background noise and the impulse disturbances of diverse location are uncorrelated mutually, with $E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]$ Result is zero, $R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right];$ According to described L _hthe intersymbol interference that individual component causes, obtains: $\left\{\begin{array}{c}{r}_k\≠r_{k+L},k=\mathrm{0,1},...,L_h-2\\ r_k=r_{k+L},k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.,$ L _cpfor the circulating prefix-length of ofdm signal, can obtain described auto-correlation function and be:

$R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right]=\left\{\begin{array}{c}\underset{i=0}{\overset{k}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=0,...,L_h-2\\ \underset{i=0}{\overset{L_h-1}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.;$

In this formula, as k ∈ [L _h-1, L _cp-1] time, calculate gained represent the average power of multipath reception signal; Because L under normal passage situation _cp>=L _h, therefore there is k=L _cp-1 makes set up, obtain the average power S of single receiving multipath signals _r=R _y(k, k+L), k=L _cp-1;

The average power sum of the OFDM digital signal that calculating receives: calculate k ∈ [0, L+L _cpthe average power sum S of the OFDM digital signal-1], i.e. receiving described in acquisition _y:

S _y=R _y(k, k)=S _r+ S _n+ S _v, S here _rfor the average power of single multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

Calculate Signal to Interference plus Noise Ratio estimator: the average power S that utilizes described single receiving multipath signals _raverage power sum S with the described OFDM digital signal receiving _ycalculate the statistic of Signal to Interference plus Noise Ratio and estimate, be designated as

Estimated result feedback: according to result of calculation, carries out channel resource allocation and channel iterative decoding.

The step of the average power of the single receiving multipath signals of described calculating also comprises: the exponent number L that calculates described channel impulse response _hvalue, make λ _k=R _y(k, k+L), k ∈ [0, L _cp-1], apply red pond information criterion and calculate described L _h: $\mathrm{AIC}\left(k\right)=-2\log \left(L_k^{(L-k)N}\right)+2V(k,L),$ Described L _kbe designated as definition V (k, L)=k (2L-k), by search AIC (k), k ∈ [0, L _cp-1], obtain the k value of minimum value position, gained k value is the exponent number L of described channel impulse response _hoptimization estimate.

Described a kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method, further comprising the steps of:

Calculate the average power of a plurality of receiving multipath signals: known channel exponent number L _hprerequisite under, obtain the average power S of the multipath reception signal of different value of K _r=R _y(k, k+L), k ∈ [L _h-1, L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{L_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L_{\mathrm{cp}}-L_h+1);$

The average power sum of the OFDM digital signal that calculating receives: calculate k ∈ [L _h-1, L+L _cp-1], obtain the average power sum S of described k the OFDM digital signal receiving _y, S _y=R _y(k, k)=S _r+ S _n+ S _v, S _rfor the average power of multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

The arithmetic average of the average power sum of the OFDM digital signal that calculating receives: according to the result of the average power sum of paid-in a plurality of OFDM digital signals, i.e. S _y=R _y(k, k), k ∈ [L _h-1, L+L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{{L+L}_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L+L_{\mathrm{cp}}-L_h+1);$

Signal to Interference plus Noise Ratio optimization is estimated: the statistic of the Signal to Interference plus Noise Ratio after calculation optimization is estimated to be designated as

The blind estimating system of ofdm system Signal to Interference plus Noise Ratio, comprises with lower module:

Digital signal reception module: the OFDM digital signal by the transmitting of antenna reception OFDM transmitter, is designated as y, y by described OFDM digital signal _kfor k the OFDM digital signal receiving, the transmitted signal r that it is superposeed by multipath _k, Gaussian Background noise n _kwith impulse disturbances v _kaddition forms, i.e. y _k=r _k+ n _k+ v _k, wherein: x _kbe k transmitted signal, a _ibe the fading channel coefficient of i paths, r _kfor the stack of multipath signal, L _hexponent number for channel impulse response;

The average power of single receiving multipath signals is calculated module: definition auto-correlation function, obtain the be separated by auto-correlation function of sub-carrier number L of k signal, for:

$\begin{array}{c}{R}_y(k,k+L)=E\left(y_k{y^{*}}_{k+L}\right)\\ =E\left[(r_k+n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\\ =E\left[r_k{r}_{k+L}^{*}\right]+E[r_k{n}_{k+L}^{*}+r_k{v}_{k+L}^{*}]+E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\end{array},$

Wherein, L is ofdm signal sub-carrier number, k ∈ [0, L-1], E (y _ky ^* _k+L) for receiving the arithmetic average after the conjugated signal of signal and displacement L multiplies each other; Because reception signal, background noise and the impulse disturbances of diverse location are uncorrelated mutually, with $E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]$ Result is zero, $R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right];$ According to described L _hthe intersymbol interference that individual component causes, obtains: $\left\{\begin{array}{c}{r}_k\≠r_{k+L},k=\mathrm{0,1},...,L_h-2\\ r_k=r_{k+L},k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.,$ L _cpfor the circulating prefix-length of ofdm signal, can obtain described auto-correlation function and be:

$R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right]=\left\{\begin{array}{c}\underset{i=0}{\overset{k}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=0,...,L_h-2\\ \underset{i=0}{\overset{L_h-1}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.;$

In this formula, as k ∈ [L _h-1, L _cp-1] time, calculate gained represent the average power of multipath reception signal; Because L under normal passage situation _cp>=L _h, therefore there is k=L _cp-1 makes set up, obtain the average power S of single receiving multipath signals _r=R _y(k, k+L), k=L _cp-1;

The average power sum computing module of the OFDM digital signal receiving: calculate k ∈ [0, L+L _cpthe average power sum S of the OFDM digital signal-1], i.e. receiving described in acquisition _y;

S _y=R _y(k, k)=S _r+ S _n+ S _v, S here _rfor the average power of single multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

Signal to Interference plus Noise Ratio estimator computing module: the average power S that utilizes described single receiving multipath signals _raverage power sum S with the described OFDM digital signal receiving _ycalculate the statistic of Signal to Interference plus Noise Ratio and estimate, be designated as

Estimated result feedback module: according to result of calculation, carries out channel resource allocation and channel iterative decoding.

The average power of described single receiving multipath signals is calculated module and is comprised: the exponent number L of channel impulse response _hcomputing module, makes λ _k=R _y(k, k+L), k ∈ [0, L _cp-1], apply red pond information criterion and calculate described L _h: $\mathrm{AIC}\left(k\right)=-2\log \left(L_k^{(L-k)N}\right)+2V(k,L),$ Described L _kbe designated as $L_k=\frac{{\mathrm{\Π}}_{i=k+1}^L{\mathrm{\λ}}_i^{\frac{1}{L-k}}}{\frac{1}{L-k}{\mathrm{\Σ}}_{i=k+1}^L{\mathrm{\λ}}_i},$ Definition V (k, L)=k (2L-k), by search AIC (k), k ∈ [0, L _cp-1], obtain the k value of minimum value position, gained k value is the exponent number L of described channel impulse response _hoptimization estimate.

The described blind estimating system of a kind of ofdm system Signal to Interference plus Noise Ratio, also comprises with lower module:

The average power of a plurality of receiving multipath signals is calculated module: known channel exponent number L _hprerequisite under, obtain the average power S of the multipath reception signal of different value of K _r=R _y(k, k+L), k ∈ [L _h-1, L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{L_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L_{\mathrm{cp}}-L_h+1);$

The average power sum computing module of the OFDM digital signal receiving: calculate k ∈ [L _h-1, L+L _cp-1], obtain the average power sum S of described k the OFDM digital signal receiving _y, S _y=R _y(k, k)=S _r+ S _n+ S _v, S _rfor the average power of multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

The arithmetic average computing module of the average power sum of the OFDM digital signal receiving: according to the result of the average power sum of paid-in a plurality of OFDM digital signals, i.e. S _y=R _y(k, k), k ∈ [L _h-1, L+L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{{L+L}_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L+L_{\mathrm{cp}}-L_h+1);$

Signal to Interference plus Noise Ratio is optimized estimation module: the statistic of the Signal to Interference plus Noise Ratio after calculation optimization is estimated to be designated as

Technique scheme of the present invention has the following advantages compared to existing technology:

A kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method and system, the transmitted signal, Gaussian Background noise and the impulse disturbances that the ofdm signal receiving are accurately divided into multipath stack, by obtaining the be separated by auto-correlation function of sub-carrier number L of k signal, calculate the average power of single receiving multipath signals, and according to the average power of single receiving multipath signals, calculating the average power sum of the OFDM digital signal receiving, the statistic that finally calculates Signal to Interference plus Noise Ratio is estimated.Calculation procedure is few, thereby saves Signal to Interference plus Noise Ratio estimated time, and estimated accuracy is high.In addition can also accurately extract channel exponent number.Finally can carry out according to Signal to Interference plus Noise Ratio estimated value distribution and the channel iterative decoding of channel resource, promote the efficiency of transmission of ofdm system.

Accompanying drawing explanation

For content of the present invention is more likely to be clearly understood, below according to a particular embodiment of the invention and by reference to the accompanying drawings, the present invention is further detailed explanation, wherein

Fig. 1 is the flow chart of a kind of ofdm system Signal to Interference plus Noise Ratio of the present invention blind estimating method;

Fig. 2 is a kind of ofdm system Signal to Interference plus Noise Ratio of the present invention blind estimating method performance chart compared to existing technology;

Fig. 3 is a kind of ofdm system Signal to Interference plus Noise Ratio of the present invention blind estimating method performance chart compared to existing technology;

Fig. 4 is a kind of ofdm system Signal to Interference plus Noise Ratio of the present invention blind estimating method performance chart compared to existing technology;

Fig. 5 is a kind of ofdm system Signal to Interference plus Noise Ratio of the present invention blind estimating method performance chart compared to existing technology;

Fig. 6 is the structured flowchart of the blind estimating system of a kind of ofdm system Signal to Interference plus Noise Ratio of the present invention.

Embodiment

Embodiment 1

Shown in Figure 1, as one embodiment of the present of invention, a kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method, comprises the following steps:

Receive digital signal: the OFDM digital signal by the transmitting of antenna reception OFDM transmitter, is designated as y, y by described OFDM digital signal _kfor k the OFDM digital signal receiving, the transmitted signal r that it is superposeed by multipath _k, Gaussian Background noise n _kwith impulse disturbances v _kaddition forms, i.e. y _k=r _k+ n _k+ v _k, wherein: x _kbe k transmitted signal, a _ibe the fading channel coefficient of i paths, r _kfor the stack of multipath signal, L _hfor the exponent number of channel impulse response, background noise n _kobeying average is zero, and variance is normal distribution, impulse disturbances v _kobeying average is zero, and variance is non-Gaussian Profile;

Calculate the average power of single receiving multipath signals: definition auto-correlation function, obtain the be separated by auto-correlation function of sub-carrier number L of k signal, for:

$\begin{array}{c}{R}_y(k,k+L)=E\left(y_k{y^{*}}_{k+L}\right)\\ =E\left[(r_k+n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\\ =E\left[r_k{r}_{k+L}^{*}\right]+E[r_k{n}_{k+L}^{*}+r_k{v}_{k+L}^{*}]+E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\end{array},$

Wherein, L is ofdm signal sub-carrier number, k ∈ [0, L-1], E (y _ky ^* _k+L) for receiving the arithmetic average after the conjugated signal of signal and displacement L multiplies each other; Because reception signal, background noise and the impulse disturbances of diverse location are uncorrelated mutually, with $E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]$ Result is zero, $R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right];$ According to described L _hthe intersymbol interference that individual component causes, obtains: $\left\{\begin{array}{c}{r}_k\≠r_{k+L},k=\mathrm{0,1},...,L_h-2\\ r_k=r_{k+L},k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.,$ L _cpfor the circulating prefix-length of ofdm signal, can obtain described auto-correlation function and be:

$R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right]=\left\{\begin{array}{c}\underset{i=0}{\overset{k}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=0,...,L_h-2\\ \underset{i=0}{\overset{L_h-1}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.;$

In this formula, as k ∈ [L _h-1, L _cp-1] time, calculate gained represent the average power of multipath reception signal; Because L under normal passage situation _cp>=L _h, therefore there is k=L _cp-1 makes set up, obtain the average power S of single receiving multipath signals _r=R _y(k, k+L), k=L _cp-1;

The average power sum of the OFDM digital signal that calculating receives: calculate k ∈ [0, L+L _cpthe average power sum S of the OFDM digital signal-1], i.e. receiving described in acquisition _y;

S _y=R _y(k, k)=S _r+ S _n+ S _v, S here _rfor the average power of single multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

Calculate Signal to Interference plus Noise Ratio estimator: the average power S that utilizes described single receiving multipath signals _raverage power sum S with the described OFDM digital signal receiving _ycalculate the statistic of Signal to Interference plus Noise Ratio and estimate, be designated as

Estimated result feedback: according to result of calculation, carries out channel resource allocation and channel iterative decoding.Carrying out the classic algorithm MAP of Turbo iterative decoding and Log-MAP algorithm while realizing, need to obtain Signal to Interference plus Noise Ratio (SINR) information that receives signal.Above-mentioned algorithm, as soft input, soft output (Soft-Input Soft-Output, SISO) decoding algorithm, need to receive prior information at input, exports posterior information simultaneously.Calculating forward-facing state probability with rear all relevant with branch metric during to state probability, and Signal to Interference plus Noise Ratio parameter is depended in the calculating of branch metric.If Signal to Interference plus Noise Ratio mismatch, i.e. decoding Signal to Interference plus Noise Ratio used does not conform to the Signal to Interference plus Noise Ratio in actual channel, can cause the reduction of decoding performance.In addition resource allocation algorithm be all the in the situation that in channel, Signal to Interference plus Noise Ratio being known just, according to the seriousness of noise jamming, optimize the transmission of assignment information, with this, obtain the lifting of transmission performance.

The step of the average power of the single receiving multipath signals of described calculating also comprises: the exponent number L that calculates described channel impulse response _hvalue, make λ _k=R _y(k, k+L), k ∈ [0, L _cp-1], apply red pond information criterion and calculate described L _h: $\mathrm{AIC}\left(k\right)=-2\log \left(L_k^{(L-k)N}\right)+2V(k,L),$ Described L _kbe designated as definition V (k, L)=k (2L-k), by search AIC (k), k ∈ [0, L _cp-1], obtain the k value of minimum value position, gained k value is the exponent number L of described channel impulse response _hoptimization estimate.

Described a kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method, further comprising the steps of:

Calculate the average power of a plurality of receiving multipath signals: known channel exponent number L _hprerequisite under, obtain the average power S of the multipath reception signal of different value of K _r=R _y(k, k+L), k ∈ [L _h-1, L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{L_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L_{\mathrm{cp}}-L_h+1);$

The average power sum of the OFDM digital signal that calculating receives: calculate k ∈ [L _h-1, L+L _cp-1], obtain the average power sum S of described k the OFDM digital signal receiving _y, S _y=R _y(k, k)=S _r+ S _n+ S _v, S _rfor the average power of multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

The arithmetic average of the average power sum of the OFDM digital signal that calculating receives: according to the result of the average power sum of paid-in a plurality of OFDM digital signals, i.e. S _y=R _y(k, k), k ∈ [L _h-1, L+L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{{L+L}_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L+L_{\mathrm{cp}}-L_h+1);$

Signal to Interference plus Noise Ratio optimization is estimated: utilize the statistic of the Signal to Interference plus Noise Ratio after the result calculation optimization of arithmetic average of the average power sum of OFDM digital signal that above-mentioned calculating receives and the average power sum of the OFDM digital signal that calculating receives to estimate to be designated as for arithmetic average, its statistical property obtaining is compared single computing can be more accurate.

Contrast prior art adopts cyclo-stationary to estimate the method for Signal to Interference plus Noise Ratio, the application has carried out Performance Ratio (Cyclostationarity Analysis curve represents the cyclo-stationary method that Chinese patent literature " CN10225586A " proposes, and Correlation Coefficient Analysis curve represents this method) at Fig. 2-Fig. 5.As seen from Figure 2, identical in other parameters, in the different situation of the noise of only having powerful connections, this method can obtain the estimated accuracy of 15dB nearly and promotes.Fig. 3 shows that impulse disturbances power is different, and in the identical situation of other parameters, at impulse disturbances power, hour this method performance boost is not remarkable, but now impulse disturbances for the impact of communication system not serious, so can ignore.And when impulse disturbances power is larger, this method has the improvement of 15dB in performance.Fig. 4 shows that impulse disturbances probability of happening is different, and under other parameter same cases, this method can obtain the performance improvement of 15-20dB in estimated accuracy.Finally, Fig. 5 shows that other parameters are identical, but the asynchronous performance comparison of data volume of each computing.From curvilinear path, can clearly see even this method is only calculated Signal to Interference plus Noise Ratio with 100 OFDM frames, its estimated accuracy obtaining is also than adopting 1000 OFDM frame estimated results of cyclo-stationary method to come highly, illustrate that this method is not only in estimated accuracy, aspect operand, also there is advantage, be easier to engineering application.

Embodiment 2

As shown in Figure 6, the blind estimating system of a kind of ofdm system Signal to Interference plus Noise Ratio, comprises with lower module:

Digital signal reception module: the OFDM digital signal by the transmitting of antenna reception OFDM transmitter, is designated as y, y by described OFDM digital signal _kfor k the OFDM digital signal receiving, the transmitted signal r that it is superposeed by multipath _k, Gaussian Background noise n _kwith impulse disturbances v _kaddition forms, i.e. y _k=r _k+ n _k+ v _k, wherein: x _kbe k transmitted signal, a _ibe the fading channel coefficient of i paths, r _kfor the stack of multipath signal, L _hfor the exponent number of channel impulse response, background noise n _kobeying average is zero, and variance is normal distribution, impulse disturbances v _kobeying average is zero, and variance is non-Gaussian Profile;

The average power of single receiving multipath signals is calculated module: definition auto-correlation function, obtain the be separated by auto-correlation function of sub-carrier number L of k signal, for:

$\begin{array}{c}{R}_y(k,k+L)=E\left(y_k{y^{*}}_{k+L}\right)\\ =E\left[(r_k+n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\\ =E\left[r_k{r}_{k+L}^{*}\right]+E[r_k{n}_{k+L}^{*}+r_k{v}_{k+L}^{*}]+E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\end{array},$

Wherein, L is ofdm signal sub-carrier number, k ∈ [0, L-1], E (y _ky ^* _k+L) for receiving the arithmetic average after the conjugated signal of signal and displacement L multiplies each other; Because reception signal, background noise and the impulse disturbances of diverse location are uncorrelated mutually, with $E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]$ Result is zero, $R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right];$ According to described L _hthe intersymbol interference that individual component causes, obtains: $\left\{\begin{array}{c}{r}_k\≠r_{k+L},k=\mathrm{0,1},...,L_h-2\\ r_k=r_{k+L},k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.,$ L _cpfor the circulating prefix-length of ofdm signal, can obtain described auto-correlation function and be:

$R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right]=\left\{\begin{array}{c}\underset{i=0}{\overset{k}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=0,...,L_h-2\\ \underset{i=0}{\overset{L_h-1}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.;$

In this formula, as k ∈ [L _h-1, L _cp-1] time, calculate gained represent the average power of multipath reception signal; Because L under normal passage situation _cp>=L _h, therefore there is k=L _cp-1 makes set up, obtain the average power S of single receiving multipath signals _r=R _y(k, k+L), k=L _cp-1;

The average power sum computing module of the OFDM digital signal receiving: calculate k ∈ [0, L+L _cpthe average power sum S of the OFDM digital signal-1], i.e. receiving described in acquisition _y;

S _y=R _y(k, k)=S _r+ S _n+ S _v, S here _rfor the average power of single multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

Signal to Interference plus Noise Ratio estimator computing module: the average power S that utilizes described single receiving multipath signals _raverage power sum S with the described OFDM digital signal receiving _ycalculate the statistic of Signal to Interference plus Noise Ratio and estimate, be designated as

Estimated result feedback module: according to result of calculation, carries out channel resource allocation and channel iterative decoding.According to result of calculation, carries out channel resource allocation and channel iterative decoding.Carrying out the classic algorithm MAP of Turbo iterative decoding and Log-MAP algorithm while realizing, need to obtain Signal to Interference plus Noise Ratio (SINR) information that receives signal.Above-mentioned algorithm, as soft input, soft output (Soft-Input Soft-Output, SISO) decoding algorithm, need to receive prior information at input, exports posterior information simultaneously.Calculating forward-facing state probability with rear all relevant with branch metric during to state probability, and Signal to Interference plus Noise Ratio parameter is depended in the calculating of branch metric.If Signal to Interference plus Noise Ratio mismatch, i.e. decoding Signal to Interference plus Noise Ratio used does not conform to the Signal to Interference plus Noise Ratio in actual channel, can cause the reduction of decoding performance.In addition resource allocation algorithm be all the in the situation that in channel, Signal to Interference plus Noise Ratio being known just, according to the seriousness of noise jamming, optimize the transmission of assignment information, with this, obtain the lifting of transmission performance.

The average power of described single receiving multipath signals is calculated module and is comprised: the exponent number L of channel impulse response _hcomputing module, makes λ _k=R _y(k, k+L), k ∈ [0, L _cp-1], apply red pond information criterion and calculate described L _h: $\mathrm{AIC}\left(k\right)=-2\log \left(L_k^{(L-k)N}\right)+2V(k,L),$ Described L _kbe designated as $L_k=\frac{{\mathrm{\Π}}_{i=k+1}^L{\mathrm{\λ}}_i^{\frac{1}{L-k}}}{\frac{1}{L-k}{\mathrm{\Σ}}_{i=k+1}^L{\mathrm{\λ}}_i},$ Definition V (k, L)=k (2L-k), by search AIC (k), k ∈ [0, L _cp-1], obtain the k value of minimum value position, gained k value is the exponent number L of described channel impulse response _hoptimization estimate.

The described blind estimating system of a kind of ofdm system Signal to Interference plus Noise Ratio, also comprises with lower module:

The average power of a plurality of receiving multipath signals is calculated module: known channel exponent number L _hprerequisite under, obtain the average power S of the multipath reception signal of different value of K _r=R _y(k, k+L), k ∈ [L _h-1, L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{L_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L_{\mathrm{cp}}-L_h+1);$

The average power sum computing module of the OFDM digital signal receiving: calculate k ∈ [L _h-1, L+L _cp-1], obtain the average power sum S of described k the OFDM digital signal receiving _y, S _y=R _y(k, k)=S _r+ S _n+ S _v, S _rfor the average power of multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

The arithmetic average computing module of the average power sum of the OFDM digital signal receiving: according to the result of the average power sum of paid-in a plurality of OFDM digital signals, i.e. S _y=R _y(k, k), k ∈ [L _h-1, L+L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{{L+L}_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L+L_{\mathrm{cp}}-L_h+1);$

Signal to Interference plus Noise Ratio is optimized estimation module: utilize the statistic of the Signal to Interference plus Noise Ratio after the result calculation optimization of arithmetic average of the average power sum of OFDM digital signal that above-mentioned calculating receives and the average power sum of the OFDM digital signal that calculating receives to estimate to be designated as SINR

Obviously, above-described embodiment is only for example is clearly described, and the not restriction to execution mode.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without also giving all execution modes.And the apparent variation of being extended out thus or change are still among the protection range in the invention.

Claims (6)

1. an ofdm system Signal to Interference plus Noise Ratio blind estimating method, is characterized in that, comprises the following steps:

Receive digital signal: the OFDM digital signal by the transmitting of antenna reception OFDM transmitter, is designated as y, y by described OFDM digital signal _kfor k the OFDM digital signal receiving, the transmitted signal r that it is superposeed by multipath _k, Gaussian Background noise n _kwith impulse disturbances v _kaddition forms, i.e. y _k=r _k+ n _k+ v _k, wherein: x _kbe k transmitted signal, a _ibe the fading channel coefficient of i paths, r _kfor the stack of multipath signal, L _hexponent number for channel impulse response;

Calculate the average power of single receiving multipath signals: definition auto-correlation function, obtain the be separated by auto-correlation function of sub-carrier number L of k signal, for:

$\begin{array}{c}{R}_y(k,k+L)=E\left(y_k{y^{*}}_{k+L}\right)\\ =E\left[(r_k+n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\\ =E\left[r_k{r}_{k+L}^{*}\right]+E[r_k{n}_{k+L}^{*}+r_k{v}_{k+L}^{*}]+E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\end{array},$

Wherein, L is ofdm signal sub-carrier number, k ∈ [0, L-1], E (y _ky ^* _k+L) for receiving the arithmetic average after the conjugated signal of signal and displacement L multiplies each other; Because reception signal, background noise and the impulse disturbances of diverse location are uncorrelated mutually, with $E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]$ Result is zero, $R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right];$ According to described L _hthe intersymbol interference that individual component causes, obtains: $\left\{\begin{array}{c}{r}_k\≠r_{k+L},k=\mathrm{0,1},...,L_h-2\\ r_k=r_{k+L},k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.,$ L _cpfor the circulating prefix-length of ofdm signal, can obtain described auto-correlation function and be:

$R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right]=\left\{\begin{array}{c}\underset{i=0}{\overset{k}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=0,...,L_h-2\\ \underset{i=0}{\overset{L_h-1}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.;$

In this formula, as k ∈ [L _h-1, L _cp-1] time, calculate gained represent the average power of multipath reception signal; Because L under normal passage situation _cp>=L _h, therefore there is k=L _cp-1 makes set up, obtain the average power S of single receiving multipath signals _r=R _y(k, k+L), k=L _cp-1;

The average power sum of the OFDM digital signal that calculating receives: calculate k ∈ [0, L+L _cpthe average power sum S of the OFDM digital signal-1], i.e. receiving described in acquisition _y:

S _y=R _y(k, k)=S _r+ S _n+ S _v, S here _rfor the average power of single multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

Calculate Signal to Interference plus Noise Ratio estimator: the average power S that utilizes described single receiving multipath signals _raverage power sum S with the described OFDM digital signal receiving _ycalculate the statistic of Signal to Interference plus Noise Ratio and estimate, be designated as

Estimated result feedback: according to result of calculation, carries out channel resource allocation and channel iterative decoding.

2. a kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method according to claim 1, is characterized in that, the step of the average power of the single receiving multipath signals of described calculating also comprises: the exponent number L that calculates described channel impulse response _hvalue, make λ _k=R _y(k, k+L), k ∈ [0, L _cp-1], apply red pond information criterion and calculate described L _h: $\mathrm{AIC}\left(k\right)=-2\log \left(L_k^{(L-k)N}\right)+2V(k,L),$ Described L _kbe designated as definition V (k, L)=k (2L-k), by search AIC (k), k ∈ [0, L _cp-1], obtain the k value of minimum value position, gained k value is the exponent number L of described channel impulse response _hoptimization estimate.

3. according to a kind of ofdm system Signal to Interference plus Noise Ratio blind estimating method described in claim 1 and 2, it is characterized in that, further comprising the steps of:

Calculate the average power of a plurality of receiving multipath signals: known channel exponent number L _hprerequisite under, obtain the average power S of the multipath reception signal of different value of K _r=R _y(k, k+L), k ∈ [L _h-1, L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{L_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L_{\mathrm{cp}}-L_h+1);$

The average power sum of the OFDM digital signal that calculating receives: calculate k ∈ [L _h-1, L+L _cp-1], obtain the average power sum S of described k the OFDM digital signal receiving _y, S _y=R _y(k, k)=S _r+ S _n+ S _v, S _rfor the average power of multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

The arithmetic average of the average power sum of the OFDM digital signal that calculating receives: according to the result of the average power sum of paid-in a plurality of OFDM digital signals, i.e. S _y=R _y(k, k), k ∈ [L _h-1, L+L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{{L+L}_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L+L_{\mathrm{cp}}-L_h+1);$

Signal to Interference plus Noise Ratio optimization is estimated: the statistic of the Signal to Interference plus Noise Ratio after calculation optimization is estimated to be designated as

4. the blind estimating system of ofdm system Signal to Interference plus Noise Ratio, is characterized in that, comprises with lower module:

Digital signal reception module: the OFDM digital signal by the transmitting of antenna reception OFDM transmitter, is designated as y, y by described OFDM digital signal _kfor k the OFDM digital signal receiving, the transmitted signal r that it is superposeed by multipath _k, Gaussian Background noise n _kwith impulse disturbances v _kaddition forms, i.e. y _k=r _k+ n _k+ v _k, wherein: x _kbe k transmitted signal, a _ibe the fading channel coefficient of i paths, r _kfor the stack of multipath signal, L _hexponent number for channel impulse response;

The average power of single receiving multipath signals is calculated module: definition auto-correlation function, obtain the be separated by auto-correlation function of sub-carrier number L of k signal, for:

$\begin{array}{c}{R}_y(k,k+L)=E\left(y_k{y^{*}}_{k+L}\right)\\ =E\left[(r_k+n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\\ =E\left[r_k{r}_{k+L}^{*}\right]+E[r_k{n}_{k+L}^{*}+r_k{v}_{k+L}^{*}]+E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]\end{array},$

Wherein, L is ofdm signal sub-carrier number, k ∈ [0, L-1], E (y _ky ^* _k+L) for receiving the arithmetic average after the conjugated signal of signal and displacement L multiplies each other; Because reception signal, background noise and the impulse disturbances of diverse location are uncorrelated mutually, with $E\left[(n_k+v_k)(r_{k+L}^{*}+n_{k+L}^{*}+v_{k+L}^{*})\right]$ Result is zero, $R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right];$ According to described L _hthe intersymbol interference that individual component causes, obtains: $\left\{\begin{array}{c}{r}_k\≠r_{k+L},k=\mathrm{0,1},...,L_h-2\\ r_k=r_{k+L},k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.,$ L _cpfor the circulating prefix-length of ofdm signal, can obtain described auto-correlation function and be:

$R_y(k,k+L)=E\left[r_k{r}_{k+L}^{*}\right]=\left\{\begin{array}{c}\underset{i=0}{\overset{k}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=0,...,L_h-2\\ \underset{i=0}{\overset{L_h-1}{\mathrm{\Σ}}}{\left|a_i\right|}^2{\mathrm{\σ}}_x^2,k=L_h-1,L_h,...,L_{\mathrm{cp}}-1\end{array}\right.;$

In this formula, as k ∈ [L _h-1, L _cp-1] time, calculate gained represent the average power of multipath reception signal; Because L under normal passage situation _cp>=L _h, therefore there is k=L _cp-1 makes set up, obtain the average power S of single receiving multipath signals _r=R _y(k, k+L), k=L _cp-1;

The average power sum computing module of the OFDM digital signal receiving: calculate k ∈ [0, L+L _cpthe average power sum S of the OFDM digital signal-1], i.e. receiving described in acquisition _y:

S _y=R _y(k, k)=S _r+ S _n+ S _v, S here _rfor the average power of single multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

Signal to Interference plus Noise Ratio estimator computing module: the average power S that utilizes described single receiving multipath signals _raverage power sum S with the described OFDM digital signal receiving _ycalculate the statistic of Signal to Interference plus Noise Ratio and estimate, be designated as

Estimated result feedback module: according to result of calculation, carries out channel resource allocation and channel iterative decoding.

5. the blind estimating system of a kind of ofdm system Signal to Interference plus Noise Ratio according to claim 1, is characterized in that, the average power of described single receiving multipath signals is calculated module and comprised: the exponent number L of channel impulse response _hcomputing module, makes λ _k=R _y(k, k+L), k ∈ [0, L _cp-1], apply red pond information criterion and calculate described L _h: $\mathrm{AIC}\left(k\right)=-2\log \left(L_k^{(L-k)N}\right)+2V(k,L),$ Described L _kbe designated as definition V (k, L)=k (2L-k), by search AIC (k), k ∈ [0, L _cp-1], obtain the k value of minimum value position, gained k value is the exponent number L of described channel impulse response _hoptimization estimate.

6. according to the blind estimating system of a kind of ofdm system Signal to Interference plus Noise Ratio described in claim 4 and 5, it is characterized in that, also comprise with lower module:

The average power of a plurality of receiving multipath signals is calculated module: known channel exponent number L _hprerequisite under, obtain the average power S of the multipath reception signal of different value of K _r=R _y(k, k+L), k ∈ [L _h-1, L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{L_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L_{\mathrm{cp}}-L_h+1);$

The average power sum computing module of the OFDM digital signal receiving: calculate k ∈ [L _h-1, L+L _cp-1], obtain the average power sum S of described k the OFDM digital signal receiving _y, S _y=R _y(k, k)=S _r+ S _n+ S _v, S _rfor the average power of multipath reception signal, S _naverage power and S for Gaussian Background noise _vaverage power for impulse disturbances;

The arithmetic average computing module of the average power sum of the OFDM digital signal receiving: according to the result of the average power sum of paid-in a plurality of OFDM digital signals, i.e. S _y=R _y(k, k), k ∈ [L _h-1, L+L _cp-1], it is done sums on average, ${\stackrel{\‾}{S}}_r=\underset{k=L_h-1}{\overset{{L+L}_{\mathrm{cp}}-1}{\mathrm{\Σ}}}{R}_y(k,k+L)/(L+L_{\mathrm{cp}}-L_h+1);$

Signal to Interference plus Noise Ratio is optimized estimation module: the statistic of the Signal to Interference plus Noise Ratio after calculation optimization is estimated to be designated as