CN102724148B - Method, device and system for information channel estimating - Google Patents

Abstract

The invention discloses a method for information channel estimating. The method includes: loading a combination of sent signals of the exiting (K-1) lines on a Kth line when the Kth line is newly added into a combination of the exiting (K-1) lines; measuring signal to noise ratio of the Kth line loaded with the combination of the signals; and calculating a crosstalk information channel of the Kth line loaded with the combination of the signals according to the coefficient of the combination of sent signals of the exiting (K-1) lines and the measured signal to noise ratio. The invention further discloses a device and a system for information channel estimating. The device is not needed to be re-designed, and the device is short in measuring time, high in accuracy and good in robustness.

Description

A kind of method, apparatus and system of channel estimating

Technical field

The present invention relates to network communication field, specifically, relate to a kind of method, apparatus and system of channel estimating.

Background technology

The data transmission technology of Digital Subscriber Line (DSL) to be a kind of with twisted pair telephone be transmission medium.X Digital Subscriber Line (xDSL), as the combination of this transmission technology, comprises high-speed digital subscriber line (HDSL), single-line high speed digital subscriber line (SHDSL), ADSL (ADSL) etc.Wherein, except utilizing the SHDSL etc. of base band transmission, adopt other xDSL of pass band transfer to utilize frequency multiplexing technique, can coexist in on a pair twisted-pair feeder with Plain Old Telephone Service (POTS).

The frequency band used along with the xDSL of pass band transfer is more and more higher, and crosstalk (Crosstalk) problem of high band also shows particularly outstanding.Prior art provides a kind of vectorial Digital Subscriber Line (vectored-DSL) technology to solve xDSL cross-interference issue, as shown in Figure 1.In the downstream direction, x is the signal vector that the joint transceiving equipment (can be Digital Subscriber Line Access Multiplexer DSLAM) of N × 1 sends, y is the signal vector that the opposite equip. (can be user side equipment) of N × 1 receives, and n is the noise vector of N × 1.Shared channel channel transfer matrices is expressed as

H _ij(1≤i≤N, 1≤j≤N) represents line to j to the crosstalk transfer function of line to i, h _ii(1≤i≤N) represents the channel transfer functions of line to i, and N is demand pairs, i.e. number of users.By introducing a vectorial precoder represented with W in joint transceiving equipment side, then the signal vector that opposite equip. receives is

$\tilde{y}=\mathrm{HWx}+n$

If vectorial precoder can make HW be pair of horns matrix, as diag (H), then crosstalk can be eliminated.In order to eliminate crosstalk, first must estimate channel, obtaining channel transfer matrices.

In prior art, be utilize signal errors to estimate channel, require that equipment must can provide signal errors.But the equipment of many online operations does not support this function, signal errors cannot be utilized to estimate channel, thus can not crosstalk counteracting be carried out.

Summary of the invention

The technical problem that the embodiment of the present invention will solve is: the method, apparatus and system providing a kind of channel estimating, overcomes the shortcoming that existing channel estimation technique requirement equipment must can provide signal errors.

For solving the problems of the technologies described above, the embodiment of the present invention provides a kind of method of channel estimating, comprise: when K article of circuit newly adds in the Vector Groups of existing K-1 article circuit, described K article of circuit loads the combination of the transmission signal of described existing K-1 article of circuit; Measure the signal to noise ratio being loaded with K article of circuit of the combination of described transmission signal; According to the coefficient of combination and the signal to noise ratio of described measurement of the transmission signal of described existing K-1 bar circuit, calculate the crosstalk channels of described K article of circuit.

The embodiment of the present invention also provides a kind of joint transceiving equipment, comprising:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Receiving element, for receiving the signal to noise ratio being loaded with K article of circuit of the combination of described transmission signal described in opposite equip. measurement;

Computing unit, for the coefficient of combination and the signal to noise ratio of described reception of the transmission signal according to described existing K-1 bar circuit, calculates the crosstalk channels of described K article of circuit.

The embodiment of the present invention also provides a kind of system of channel estimating, comprising: joint transceiving equipment and opposite equip.;

Described joint transceiving equipment comprises:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Receiving element, for receiving the signal to noise ratio being loaded with K article of circuit of the combination of described signal described in opposite equip. measurement;

Computing unit, for the coefficient of combination and the signal to noise ratio of described reception of the transmission signal according to described existing K-1 bar circuit, calculates the crosstalk channels of described K article of circuit;

Described opposite equip., comprising:

Measuring unit, for being loaded with the signal to noise ratio of K article of circuit of the combination of described signal described in measuring;

Transmitting element, for sending the signal to noise ratio of described measurement to described joint transceiving equipment.

The embodiment of the present invention also provides a kind of joint transceiving equipment, comprising:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Transmitting element, for sending the coefficient of the combination of the transmission signal of described existing K-1 bar circuit to opposite equip.;

Receiving element, for receiving the crosstalk channels being loaded with K article of circuit of the combination of described signal described in the calculating of described opposite equip..

The embodiment of the present invention also provides a kind of system of channel estimating, comprising: joint transceiving equipment and opposite equip.;

Described joint transceiving equipment comprises:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Transmitting element, for sending the coefficient of the combination of the transmission signal of described existing K-1 bar circuit to opposite equip.;

Receiving element, for receiving the crosstalk channels being loaded with K article of circuit of the combination of described signal described in the calculating of described opposite equip.;

Described opposite equip., comprising:

Measuring unit, for measuring the signal to noise ratio of described K article of circuit;

Receiving element, for receiving the coefficient of the combination of the transmission signal of the described existing K-1 bar circuit that described joint transceiving equipment sends;

Computing unit, for the coefficient of combination and the signal to noise ratio of described measurement of the transmission signal according to described existing K-1 bar circuit, calculates the crosstalk channels of described K article of circuit;

Transmitting element, for sending the crosstalk channels of described calculating to described joint transceiving equipment.

The technical scheme provided as can be seen from the invention described above embodiment, the invention provides a kind of method, apparatus and system of channel estimating, utilize the equipment of existing network can provide the feature of signal to noise ratio (SNR) parameter, calculated the crosstalk effect of circuit by the combination of transmission signal of the All other routes of the SNR parameter measured and loading.The technical scheme that the embodiment of the present invention provides, do not need redesign equipment, and Measuring Time is short, and precision is high and have good robustness.

Accompanying drawing explanation

Fig. 1 is the schematic diagram that in prior art, vectored-DSL technology solves xDSL crosstalk;

Fig. 2 is the method schematic diagram of the embodiment of the present invention one channel estimating;

Fig. 3 is the system schematic of the embodiment of the present invention two channel estimating;

Fig. 4 is the structural representation of the loading unit of the embodiment of the present invention two joint transceiving equipment;

Fig. 5 is the system schematic of the embodiment of the present invention three channel estimating;

Fig. 6 is the structural representation of the loading unit of the joint transceiving equipment of the embodiment of the present invention three.

Detailed description of the invention

The embodiment of the present invention, had both gone for estimating crosstalk channel when new user reaches the standard grade, and also went for carrying out the scene such as following the tracks of to crosstalk channels.All add Vector Groups (vector group) for new user to be below described.Suppose existing K-1 bar circuit in a Vector Groups, when K article of new line requires to add this Vector Groups, other K-1 article circuit can be estimated by the signal to noise ratio (SNR) that K article of circuit is measured respectively to the crosstalk of K article of circuit.

Be illustrated in figure 2 the method schematic diagram of the embodiment of the present invention one channel estimating.The step that the present embodiment carries out channel estimating is as follows:

Step 101: the combination loading the transmission signal of other circuit on a circuit of channel;

This step is specially joint transceiving equipment on certain sub-band of the down direction of circuit K, injects the combination of all or part of signal of the transmission signal of circuit 1 to circuit K-1 simultaneously.Be loaded with the signal of which circuit, which circuit just can be calculated by the embodiment of the present invention the crosstalk of K article of circuit.Each sub-band is carry out above-mentioned process side by side.

Here example is combined as with whole signals of the transmission signal of Load Line 1 to circuit K-1.Suppose that SNR pendulous frequency required on circuit K is N, each SNR measurement needs the time of lasting L symbol (symbol), and other K-1 bar circuit has entered showtime state.Assuming that measure the signal sent needed for l symbol on period i-th article of circuit at the n-th SNR be so on this circuit, the actual signal sent is when K article of circuit joins Vector Groups, other circuit continues to send original signal, then have:

$x_i^{\left(n\right)}\left(l\right)=s_i^{\left(n\right)}\left(l\right),\&ForAll;i<K.$

By adding every other 1 to the combination of transmission signal of K-1 article of circuit on the transmission signal of K article of circuit, then K article of circuit be loaded after transmission signal be:

$x_K^{\left(n\right)}\left(l\right)=s_K^{\left(n\right)}\left(l\right)+\mathrm{\&epsiv;}\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{z}_i^{\left(n\right)}{s}_i^{\left(n\right)}\left(l\right).$

Wherein, for measuring the combination coefficient of period i-th circuit at the n-th SNR, and meet:

$\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|z_i^{\left(n\right)}\right|}^2=1.$

The quadratic sum of the absolute value of combination coefficient is 1, is a preferred embodiment of the present invention, also can be other coefficient.

ε is step-length, is to make the impact of signal on K article of circuit of loading be unlikely to produce extra error code, being not less than zero after requiring to add the signal of loading here in the SNR tolerance limit of the receiving terminal of K article of circuit.Generally, the Signal to Noise Ratio Margin of circuit is set to 6dB, to be on the safe side, should ensure that the receiving terminal SNR reduction of K article of circuit after loading is not more than 3.5dB.The present embodiment arranges ε by formula below, to meet above-mentioned requirements:

$\mathrm{\&epsiv;}=\underset{i}{\min }\frac{1}{2}\frac{1}{\sqrt{{\mathrm{SNR}}_K^{\left(0\right)}}}\frac{{\mathrm{\&sigma;}}_K}{{\mathrm{\&sigma;}}_i},$

Wherein, represent the transmitted power (transmitted power of the known each bar circuit of joint transceiving equipment) on i-th circuit; represent the signal to noise ratio of K article of circuit receiving terminal when not being loaded signal.

Step 102: measure the signal to noise ratio being loaded circuit;

This step is specially the signal to noise ratio in the above-mentioned same sub-band of the down direction of opposite equip. measurement circuitry K, and signal to noise ratio directly measures to obtain.

Step 103: according to the coefficient of combination and the signal to noise ratio of measurement of the transmission signal of other circuit, calculates the crosstalk channels being loaded circuit.

This step be specially joint transceiving equipment be loaded according to the circuit K that opposite equip. feeds back after signal to noise ratio and the crosstalk channels of coefficient calculations circuit K of combination of transmission signal of other circuit; Or the coefficient of the combination of the transmission signal of other circuit is sent to opposite equip. for joint transceiving equipment, the crosstalk channels of the coefficient calculations circuit K of the combination of the transmission signal of the signal to noise ratio after opposite equip. is loaded according to the circuit K measured and other circuit of reception.

Calculate the derivation being loaded the crosstalk channels of circuit as follows:

The formula of the transmission signal after being loaded according to K article of circuit in step 101, then the signal that the opposite equip. of K article of circuit receives is:

$y_k^{\left(n\right)}\left(l\right)=\underset{i=1}{\overset{K}{\mathrm{\&Sigma;}}}{h}_{K,i}{x}_i^{\left(n\right)}\left(l\right)+w_K^{\left(n\right)}\left(l\right)$

$=h_{K,K}{s}_K^{\left(n\right)}\left(l\right)+\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}(h_{K,i}+\mathrm{\&epsiv;}{z}_i^{\left(n\right)}{h}_{K,K})s_i^{\left(n\right)}\left(l\right)+w_K^{\left(n\right)}\left(l\right).$

Wherein, the signal power of reception is:

${\mathrm{signal}}_K=\frac{1}{L}\underset{l=1}{\overset{L}{\mathrm{\&Sigma;}}}{\left|h_{K,K}{s}_K^{\left(n\right)}\left(l\right)\right|}^2$

$\&ap;{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2.$

The noise power received is:

${\mathrm{noise}}_K=\frac{1}{L}\underset{l=1}{\overset{L}{\mathrm{\&Sigma;}}}|{y_K^{\left(n\right)}\left(l\right)-h_{K,K}{s}_K^{\left(n\right)}\left(l\right)|}^2$

$\&ap;\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{|h_{K,i}+\mathrm{\&epsiv;}{z}_i^{\left(n\right)}{h}_{K,K}|}^2{\mathrm{\&sigma;}}_i^2+{\mathrm{\&sigma;}}_{W_K}^2,$

Wherein, represent the power of ambient noise.

According to above-mentioned two formula, when the transmitted power of each bar circuit is equal, namely sNR measured by the opposite equip. of K article of circuit can be represented by following formula:

$\frac{1}{{\mathrm{SNR}}_K^{\left(n\right)}}=\frac{\mathrm{nois}{e}_K}{{\mathrm{signal}}_K}$

$\&ap;\frac{1}{{\mathrm{\&sigma;}}_K^2}(\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{|\frac{h_{K,i}}{h_{K,K}}{\mathrm{\&sigma;}}_i+\mathrm{\&epsiv;}{z}_i^{\left(n\right)}{\mathrm{\&sigma;}}_i|}^2+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2})$

$=\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{|\frac{h_{K,i}}{h_{K,K}}+\mathrm{\&epsiv;}{z}_i^{\left(n\right)}|}^2+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2}$

$={\left|\right|\stackrel{\&OverBar;}{a}+\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2}$

And work as ${\mathrm{\&sigma;}}_i^2={\mathrm{\&sigma;}}_K^2$ Time, step-length is

$\mathrm{\&epsiv;}=\underset{i}{\min }\frac{1}{2}\frac{1}{\sqrt{{\mathrm{SNR}}_K^{\left(0\right)}}},$

Definition $\stackrel{\&OverBar;}{a}={[{\stackrel{\&OverBar;}{a}}_1...{\stackrel{\&OverBar;}{a}}_{K-1}]}^T,$ ${\stackrel{\&OverBar;}{b}}^{\left(n\right)}={[{\stackrel{\&OverBar;}{b}}_1^{\left(n\right)}...{\stackrel{\&OverBar;}{b}}_{K-1}^{\left(n\right)}]}^T,$ ${\stackrel{\&OverBar;}{a}}_i=\frac{h_{K,i}}{h_{K,K}},$ ${\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}=z_i^{\left(n\right)}.$ According to Pythagorean theorem, have

${\left|\right|\stackrel{\&OverBar;}{a}+\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2={\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+2\mathrm{\&epsiv;Re}\left\{{\stackrel{\&OverBar;}{b}}^{{\left(n\right)}^H}\stackrel{\&OverBar;}{a}\right\}.$

Will with be decomposed into real part and imaginary part respectively, namely $a_{R,i}=\mathrm{Re}\left\{{\stackrel{\&OverBar;}{a}}_i\right\},$ $a_{I,i}=\mathrm{Im}\left\{{\stackrel{\&OverBar;}{a}}_i\right\},$ $b_{R,i}^{\left(n\right)}=\mathrm{Re}\left\{{\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}\right\},$ $b_{I,i}^{\left(n\right)}=\mathrm{Im}\left\{{\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}\right\},$ Then have

$\mathrm{Re}\left\{{\stackrel{\&OverBar;}{b}}^{{\left(n\right)}^H}\stackrel{\&OverBar;}{a}\right\}=\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}[a_{R,i}{b}_{R,i}^{\left(n\right)}+a_{I,i}{b}_{I,i}^{\left(n\right)}]$

$=b^{{\left(n\right)}^H}a,$

Wherein, a=[a _{r, 1}... a _{r, K-1}a _{i, 1}... a _{i, K-1}] ^t, conveniently, a is defined _i=[a] _i, according to above-mentioned two formula, can obtain

${\left|\right|\stackrel{\&OverBar;}{a}+\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2={\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+2\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a.$

According to the expression formula of above formula and SNR above, have

${\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+2\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2}=\frac{1}{{\mathrm{SNR}}_K^{\left(n\right)}}.$

Therefore,

$\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2}=\frac{1}{2}\frac{1}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2.$

Again due to ${\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}=z_i^{\left(n\right)},$ Then

$\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2}=\frac{1}{2}\frac{1}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\mathrm{\&epsiv;}}^2\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|z_i^{\left(n\right)}\right|}^2.$

Definition $c^{\left(n\right)}=\frac{1}{2}\frac{{\mathrm{\&sigma;}}_K^2}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\mathrm{\&epsiv;}}^2\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|z_i^{\left(n\right)}\right|}^2,$ Then

$\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2}=c^{\left(n\right)},\&ForAll;n.$

Define the matrix P that a size is M × N, and its element p _{m, n}=[P] _{m, n}meet

$\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_{m,n}=0,\&ForAll;m.$

It, as the combinatorial matrix of SNR, has

$\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{c}^{\left(n\right)}=\mathrm{\&epsiv;}\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{b}^{{\left(n\right)}^H}a+(\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2{\mathrm{\&sigma;}}_K^2})\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n},\&ForAll;m.$

Due to $\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_{m,n}=0,\&ForAll;m,$ Then have

$\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{c}^{\left(n\right)}=\mathrm{\&epsiv;}\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{b}^{{\left(n\right)}^H}a,\&ForAll;m.$

To each n, there is the formula of an above-mentioned form.All these formula are merged into a matrix, have

$P\left[\begin{array}{c}{c}^{\left(1\right)}\\ .\\ .\\ .\\ c^{\left(N\right)}\end{array}\right]=\mathrm{\&epsiv;P}\left[\begin{array}{c}{b}^{{\left(1\right)}^H}\\ .\\ .\\ .\\ b^{{\left(N\right)}^H}\end{array}\right]a.$

Definition c=[c ⁽¹⁾... c ^(N)] ^twith B=[b ⁽¹⁾... b ^(N)] ^h. therefore, have

εPBa＝Pc.

Then the least square solution of a is

a＝ε ^-1pinv(PB)Pc，

Wherein, pinv (.) represents pseudo-inverse operation.

After solving a, then basis with a=[a _{r, 1}... a _{r, K-1}a _{i, 1}... a _{i, K-1}] ^t, just can obtain through the normalized crosstalk channels of direct channels, as shown in the formula expression:

$\frac{h_{K,i}}{h_{K,K}}=a_i+j{a}_{K-1+i}$

According to above-mentioned derivation, the concrete steps calculating crosstalk channels are as follows:

Select suitable combinatorial matrix, according to the coefficient of the combination of the transmission signal on each bar circuit, calculate G=pinv (PB) P; According to the coefficient of combination and the SNR of measurement of the transmission signal on each bar circuit, calculate according to above-mentioned result of calculation, calculate a=ε ^-1gc; Finally, draw through the normalized crosstalk channels of direct channels $\frac{h_{K,i}}{h_{K,K}}=a_i+j{a}_{K-1+i},\&ForAll;i.$

And when the transmitted power of each bar circuit is unequal, the SNR measured by the opposite equip. of K article of circuit can be represented by following formula:

$\frac{1}{{\mathrm{SNR}}_K^{\left(n\right)}}=\frac{\mathrm{nois}{e}_K}{{\mathrm{signal}}_K}$

$\&ap;\frac{1}{{\mathrm{\&sigma;}}_K^2}(\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{|\frac{h_{K,i}}{h_{K,K}}{\mathrm{\&sigma;}}_i+\mathrm{\&epsiv;}{z}_i^{\left(n\right)}{\mathrm{\&sigma;}}_i|}^2+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2})$

$=\frac{1}{{\mathrm{\&sigma;}}_K^2}({\left|\right|\stackrel{\&OverBar;}{a}+\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2}),$

Definition $\stackrel{\&OverBar;}{a}={[{\stackrel{\&OverBar;}{a}}_1...{\stackrel{\&OverBar;}{a}}_{K-1}]}^T,$ ${\stackrel{\&OverBar;}{b}}^{\left(n\right)}=[{{\stackrel{\&OverBar;}{b}}_1^{\left(n\right)}...{\stackrel{\&OverBar;}{b}}_{K-1}^{\left(n\right)}]}^T,$ ${\stackrel{\&OverBar;}{a}}_i=\frac{h_{K,i}}{h_{K,K}}{\mathrm{\&sigma;}}_i,$ ${\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}=z_i^{\left(n\right)}{\mathrm{\&sigma;}}_i.$ According to Pythagorean theorem, have

${\left|\right|\stackrel{\&OverBar;}{a}+\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2={\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+2\mathrm{\&epsiv;Re}\left\{{\stackrel{\&OverBar;}{b}}^{{\left(n\right)}^H}\stackrel{\&OverBar;}{a}\right\}.$

Will with be decomposed into real part and imaginary part respectively, namely $a_{R,i}=\mathrm{Re}\left\{{\stackrel{\&OverBar;}{a}}_i\right\},$ $a_{I,i}=\mathrm{Im}\left\{{\stackrel{\&OverBar;}{a}}_i\right\},$ $b_{R,i}^{\left(n\right)}=\mathrm{Re}\left\{{\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}\right\},$ $b_{I,i}^{\left(n\right)}=\mathrm{Im}\left\{{\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}\right\},$ Then have

$\mathrm{Re}\left\{{\stackrel{\&OverBar;}{b}}^{{\left(n\right)}^H}\stackrel{\&OverBar;}{a}\right\}=\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}[a_{R,i}{b}_{R,i}^{\left(n\right)}+a_{I,i}{b}_{I,i}^{\left(n\right)}]$

$=b^{{\left(n\right)}^H}a,$

Wherein, a=[a _{r, 1}... a _{r, K-1}a _{i, 1}... a _{i, K-1}] ^t, $b^{\left(n\right)}={\left[\begin{array}{cc}{b}_{R,1}^{\left(n\right)}...b_{R,K-1}^{\left(n\right)}& b_{I,1}^{\left(n\right)}...b_{I,K-1}^{\left(n\right)}\end{array}\right]}^T.$ Conveniently, a is defined _i=[a] _i, according to above-mentioned two formula, can obtain

${\left|\right|\stackrel{\&OverBar;}{a}+\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2={\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+2\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a.$

According to the expression formula of above formula and SNR above, have

${\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2+2\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2}=\frac{{\mathrm{\&sigma;}}_K^2}{{\mathrm{SNR}}_K^{\left(n\right)}}.$

Therefore,

$\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2}=\frac{1}{2}\frac{{\mathrm{\&sigma;}}_K^2}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\left|\right|\mathrm{\&epsiv;}{\stackrel{\&OverBar;}{b}}^{\left(n\right)}\left|\right|}^2.$

Again due to ${\stackrel{\&OverBar;}{b}}_i^{\left(n\right)}=z_i^{\left(n\right)}{\mathrm{\&sigma;}}_i,$ Then

$\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2}=\frac{1}{2}\frac{{\mathrm{\&sigma;}}_K^2}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\mathrm{\&epsiv;}}^2\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|z_i^{\left(n\right)}\right|}^2{\mathrm{\&sigma;}}_i^2.$

Definition $c^{\left(n\right)}=\frac{1}{2}\frac{{\mathrm{\&sigma;}}_K^2}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\mathrm{\&epsiv;}}^2\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|z_i^{\left(n\right)}\right|}^2{\mathrm{\&sigma;}}_i^2,$ Then

$\mathrm{\&epsiv;}{b}^{{\left(n\right)}^H}a+\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2}=c^{\left(n\right)},\&ForAll;n.$

Define the matrix P that a size is M × N, and its element p _{m, n}=[P] _{m, n}meet

$\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_{m,n}=0,\&ForAll;m.$

It, as the combinatorial matrix of SNR, has

$\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{c}^{\left(n\right)}=\mathrm{\&epsiv;}\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{b}^{{\left(n\right)}^H}a+(\frac{1}{2}{\left|\right|\stackrel{\&OverBar;}{a}\left|\right|}^2+\frac{1}{2}\frac{{\mathrm{\&sigma;}}_{W_K}^2}{{\left|h_{K,K}\right|}^2})\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n},\&ForAll;m.$

Due to $\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{p}_{m,n}=0,\&ForAll;m,$ Then have

$\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{c}^{\left(n\right)}=\mathrm{\&epsiv;}\underset{n}{\mathrm{\&Sigma;}}{p}_{m,n}{b}^{{\left(n\right)}^H}a,\&ForAll;m.$

To each n, there is the formula of an above-mentioned form.All these formula are merged into a matrix, have

$P\left[\begin{array}{c}{c}^{\left(1\right)}\\ .\\ .\\ .\\ c^{\left(N\right)}\end{array}\right]=\mathrm{\&epsiv;P}\left[\begin{array}{c}{b}^{{\left(1\right)}^H}\\ .\\ .\\ .\\ b^{{\left(N\right)}^H}\end{array}\right]a.$

Definition c=[c ⁽¹⁾... c ^(N)] ^twith B=[b ⁽¹⁾... b ^(N)] ^h. therefore, have

εPBa＝Pc.

Then the least square solution of a is

a＝ε ^-1pinv(PB)Pc

Wherein, pinv (.) represents pseudo-inverse operation.

After solving a, then basis with a=[a _{r, 1}... a _{r, K-1}a _{i, 1}... a _{i, K-1}] ^t, just can obtain through the normalized crosstalk channels of direct channels, as shown in the formula expression:

$\frac{h_{K,i}}{h_{K,K}}=\frac{1}{{\mathrm{\&sigma;}}_i}(a_i+j{a}_{K-1+i}),$

According to above-mentioned derivation, the concrete steps now calculating crosstalk channels are as follows:

Select suitable combinatorial matrix, according to the coefficient of the transmitted power on each bar circuit with the combination of transmission signal, calculate G=pinv (PB) P; According to the transmitted power on each bar circuit, the coefficient of combination sending signal and the SNR of measurement, calculate $c^{\left(n\right)}=\frac{1}{2}\frac{{\mathrm{\&sigma;}}_K^2}{{\mathrm{SNR}}_K^{\left(n\right)}}-\frac{1}{2}{\mathrm{\&epsiv;}}^2\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left(z_i^{\left(n\right)}\right)}^2{\mathrm{\&sigma;}}_i^2;$ According to above-mentioned result of calculation, calculate a=ε ^-1gc; Finally, draw through the normalized crosstalk channels of direct channels

In order to make performance when general, best performance, can select matrix P and B in advance.Carry out following selection especially:

The coefficient defining normalized discrete cosine transform is as follows:

$u_{n,m}=\left\{\begin{array}{cc}\sqrt{\frac{2}{N}}\cos \left(\frac{\mathrm{\&pi;}(n+0.5)m}{N}\right)& t>1,n>1,\\ \frac{1}{\sqrt{N}}& \mathrm{otherwise}.\end{array}\right.$

Above-mentioned coefficient is write as matrix form, and the DC terms removing the first row obtains:

Selected U ^has detectable signal matrix: B=U ^h.Like this, setting SNR

Combinatorial matrix is: the reason why P=U. so selects is, makes the error of channel estimating minimum when the SNR fed back is interfered.A reason in addition selects such matrix that us can be made not need to calculate the pseudoinverse of PB matrix product.G matrix in the algorithm can directly be obtained by matrix P.As shown in the formula.The computational complexity of algorithm can be reduced like this.

G＝pinv(PB)P

＝pinv(UU ^H)P

＝P.

In addition, if the quantity of user is the n power of 2, we can select Walsh-Hadamard sequence to generate matrix B.Another benefit is like this that the multiplication in computational process just can replace with simple addition and subtraction because Walsh-Hadamard sequence has a positive and negative formation.As long as what the Arbitrary Matrix B certainly meeting this method requirement can be correct calculates channel matrix, this method is not limited to above-mentioned system of selection.

Utilize different combination coefficients, repetition step 101 and step 102 should be no less than 2K-1 time, just can calculate every other K-1 article circuit to the crosstalk of K article of circuit.The number of times of above-mentioned repetition step 101 and step 102 determines according to the number (number of the crosstalk namely will measured) of the All other routes loaded.

Above-mentioned whole process can repeatedly, and constantly update crosstalk channels, the object of repetition is to improve precision or carrying out line trace.

Can also according to the crosstalk channels calculated, the crosstalk counteracting precompensation wave filter of design first approximation, as shown in the formula:

Wherein, offdiag (X)=X-diag (X).

The method of the channel estimating that the present embodiment provides, by the combination being loaded the transmission signal of the SNR parameter of circuit and other circuit of loading of measuring, calculates the crosstalk effect being loaded circuit.The present embodiment does not need redesign equipment, and Measuring Time is short, and precision is high and have good robustness.

Be illustrated in figure 3 the system schematic of the embodiment of the present invention two channel estimating, this system at least comprises joint transceiving equipment 1 and opposite equip. 2.

Wherein, joint transceiving equipment 1 comprises: loading unit 11, receiving element 12 and computing unit 13.Loading unit 11, for loading the combination of the transmission signal of other circuit on a circuit of channel; Receiving element 12, for receiving the signal to noise ratio being loaded circuit that opposite equip. is measured; Computing unit 13, for the coefficient of combination and the signal to noise ratio of reception of the transmission signal according to other circuit, calculates the crosstalk channels being loaded circuit.

Correspondingly, opposite equip. 2 comprises measuring unit 21, transmitting element 22.Measuring unit 21, for being loaded the signal to noise ratio of circuit described in measuring; Transmitting element 22, for sending the signal to noise ratio of measurement to joint transceiving equipment.

Be illustrated in figure 4 the structural representation of the loading unit of the present embodiment joint transceiving equipment.The loading unit 11 of joint transceiving equipment may further include: the first computing unit 111 and the first loading unit 112.First computing unit 111, for calculating the combination of transmission signal and the product of step-length of other circuit; First loading unit 112, for being loaded the combination of transmission signal and the product of step-length that circuit load other circuit.

First computing unit 111 can further include: the second computing unit 1111, for according to the transmitted power of each bar circuit and the signal-to-noise ratio computation step-length that is loaded when circuit is not loaded.

The computing unit 13 of the present embodiment joint transceiving equipment, also for the transmitted power according to step-length and each bar circuit, calculates the crosstalk channels being loaded circuit.

The system of the channel estimating that the present embodiment provides and equipment, by the combination being loaded the transmission signal of the SNR parameter of circuit and other circuit of loading of measuring, calculate the crosstalk effect being loaded circuit.The present embodiment does not need redesign equipment, and Measuring Time is short, and precision is high and have good robustness.

Be illustrated in figure 5 the system schematic of the embodiment of the present invention three channel estimating.This system at least comprises joint transceiving equipment 3 and opposite equip. 4.

Wherein, joint transceiving equipment 3 comprises: loading unit 31, transmitting element 32 and receiving element 33.Loading unit 31, for loading the combination of the transmission signal of other circuit on a circuit of channel; Transmitting element 32, for sending the coefficient of the combination of the transmission signal of other circuit described to opposite equip.; Receiving element 33, for receiving the crosstalk channels being loaded circuit that opposite equip. calculates.

Correspondingly, opposite equip. 4 comprises: measuring unit 41, receiving element 42, computing unit 43 and transmitting element 44.Measuring unit 41, for measuring the signal to noise ratio being loaded circuit; Receiving element 42, for receiving the coefficient of the combination of the transmission signal of other circuit that joint transceiving equipment sends; Computing unit 43, for the coefficient of combination and the signal to noise ratio of measurement of the transmission signal according to other circuit, calculates the crosstalk channels being loaded circuit; Transmitting element 44, for sending the crosstalk channels of calculating to joint transceiving equipment.

Be illustrated in figure 6 the structural representation of the loading unit of the present embodiment joint transceiving equipment.The loading unit 31 of joint transceiving equipment may further include: the first computing unit 311 and the first loading unit 312.First computing unit 311, for calculating the combination of transmission signal and the product of step-length of other circuit; First loading unit 312, for being loaded the combination of transmission signal and the product of step-length that circuit load other circuit.

First computing unit 311 can further include: the second computing unit 3111, for according to the transmitted power of each bar circuit and the signal-to-noise ratio computation step-length that is loaded when circuit is not loaded.

The transmitting element 32 of the present embodiment joint transceiving equipment 3, also for sending the transmitted power of step-length and each bar circuit to opposite equip..

Correspondingly, the receiving element 42 of the present embodiment opposite equip. 4, also for receiving the step-length and the transmitted power of each bar circuit that joint transceiving equipment sends; Computing unit 43, also for the transmitted power according to the step-length received and each bar circuit, calculates the crosstalk channels being loaded circuit.

The system of the channel estimating that the present embodiment provides and equipment, by the combination being loaded the transmission signal of the SNR parameter of circuit and other circuit of loading of measuring, calculate the crosstalk effect being loaded circuit.The present embodiment does not need redesign equipment, and Measuring Time is short, and precision is high and have good robustness.

The above; be only the present invention's preferably detailed description of the invention, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.

Claims (18)

1. a method for channel estimating, is characterized in that, comprising:

When K article of circuit newly adds the Vector Groups of existing K-1 article circuit, described K article of circuit loads the combination of the transmission signal of described existing K-1 article of circuit;

Measure the signal to noise ratio being loaded with K article of circuit of the combination of described transmission signal;

According to the coefficient of combination and the signal to noise ratio of described measurement of the transmission signal of described existing K-1 bar circuit, calculate the crosstalk channels of described K article of circuit.

2. the method for a kind of channel estimating as claimed in claim 1, is characterized in that, described K article of circuit loads the combination of the transmission signal of described existing K-1 article of circuit, specifically comprises: according to formula the transmission signal of K article of circuit adds the combination of the transmission signal of existing 1 to the K-1 article circuit, and wherein, ε is step-length, for measuring the combination coefficient of period i-th circuit at the n-th SNR, for measuring the signal sent needed for l symbol on period i-th article of circuit at the n-th SNR, it is the actual signal sent on K article of circuit.

3. the method for a kind of channel estimating as claimed in claim 2, is characterized in that, described in meet $\underset{i=1}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|z_i^{\left(n\right)}\right|}^2=1.$

4. the method for a kind of channel estimating as claimed in claim 2, is characterized in that, described ε meets wherein, represent the transmitted power on i-th circuit; represent the signal to noise ratio of kth bar circuit receiving terminal when not being loaded signal.

5. the method for a kind of channel estimating as claimed in claim 2, described ε is set to a value, makes the receiving terminal SNR decreasing value of K article of circuit after being loaded with the combination sending signal be not more than 3.5dB.

6. the method for a kind of channel estimating as described in any one of claim 1 to 5, is characterized in that, the crosstalk channels of described K article of circuit is the normalized crosstalk channels of direct channels through described K article of circuit.

7. a joint transceiving equipment, is characterized in that, comprising:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Receiving element, for receiving the signal to noise ratio being loaded with K article of circuit of the combination of described transmission signal described in opposite equip. measurement;

Computing unit, for the coefficient of combination and the signal to noise ratio of described reception of the transmission signal according to described existing K-1 bar circuit, calculates the crosstalk channels of described K article of circuit.

8. a kind of joint transceiving equipment as claimed in claim 7, is characterized in that, described loading unit comprises:

First computing unit, for calculating the combination of transmission signal and the product of step-length of described existing K-1 bar circuit;

First loading unit, for loading the combination of the transmission signal of described existing K-1 article of circuit and the product of described step-length on described K article of circuit.

9. a kind of joint transceiving equipment as claimed in claim 8, is characterized in that, described first computing unit comprises further:

Second computing unit, for step-length according to the transmitted power of each article of circuit and the signal-to-noise ratio computation of described K article of circuit when not being loaded the combination of described transmission signal.

10. a kind of joint transceiving equipment as claimed in claim 9, is characterized in that, described computing unit, also for the transmitted power according to described step-length and described each bar circuit, calculates the crosstalk channels of described K article of circuit.

The system of 11. 1 kinds of channel estimating, is characterized in that, comprising: joint transceiving equipment and opposite equip.;

Described joint transceiving equipment comprises:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Receiving element, for receiving the signal to noise ratio being loaded with K article of circuit of the combination of described transmission signal described in opposite equip. measurement;

Computing unit, for the coefficient of combination and the signal to noise ratio of described reception of the transmission signal according to described existing K-1 bar circuit, calculates the crosstalk channels of described K article of circuit;

Described opposite equip., comprising:

Measuring unit, for being loaded with the signal to noise ratio of K article of circuit of the combination of described transmission signal described in measuring;

Transmitting element, for sending the signal to noise ratio of described measurement to described joint transceiving equipment.

The system of 12. a kind of channel estimating as claimed in claim 11, is characterized in that, described computing unit, also for the transmitted power according to step-length and each bar circuit, calculates the crosstalk channels of described K article of circuit.

13. 1 kinds of joint transceiving equipment, is characterized in that, comprising:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Transmitting element, for sending the coefficient of the combination of the transmission signal of described existing K-1 bar circuit to opposite equip.;

Receiving element, for receiving the crosstalk channels being loaded with K article of circuit of the combination of described transmission signal described in the calculating of described opposite equip..

14. a kind of joint transceiving equipment as claimed in claim 13, it is characterized in that, described loading unit comprises:

First computing unit, for calculating the combination of transmission signal and the product of step-length of described existing K-1 bar circuit;

First loading unit, for loading the combination of the transmission signal of described existing K-1 article of circuit and the product of described step-length on described K article of circuit.

15. a kind of joint transceiving equipment as claimed in claim 14, is characterized in that, described first computing unit comprises further:

Second computing unit, for step-length according to the transmitted power of each article of circuit and the signal-to-noise ratio computation of described K article of circuit when not being loaded the combination of described transmission signal.

16. a kind of joint transceiving equipment as claimed in claim 15, is characterized in that, described transmitting element, also for sending the transmitted power of described step-length and described each bar circuit to described opposite equip..

The system of 17. 1 kinds of channel estimating, is characterized in that, comprising: joint transceiving equipment and opposite equip.;

Described joint transceiving equipment comprises:

Loading unit, for loading the combination of the transmission signal of existing K-1 article circuit on K article of circuit; Described K article of circuit is the circuit newly added;

Transmitting element, for sending the coefficient of the combination of the transmission signal of described existing K-1 bar circuit to opposite equip.;

Receiving element, for receiving the crosstalk channels being loaded with K article of circuit of the combination of described transmission signal described in the calculating of described opposite equip.;

Described opposite equip., comprising:

Measuring unit, for measuring the signal to noise ratio of described K article of circuit;

Receiving element, for receiving the coefficient of the combination of the transmission signal of the described existing K-1 bar circuit that described joint transceiving equipment sends;

Computing unit, for the coefficient of combination and the signal to noise ratio of described measurement of the transmission signal according to described existing K-1 bar circuit, calculates the crosstalk channels of described K article of circuit;

Transmitting element, for sending the crosstalk channels of described calculating to described joint transceiving equipment.

The system of 18. a kind of channel estimating as claimed in claim 17, is characterized in that, the transmitting element of described joint transceiving equipment, also for sending the transmitted power of step-length and each bar circuit to described opposite equip.;

The computing unit of described opposite equip., also for the transmitted power according to described step-length and described each bar circuit, calculates the crosstalk channels of described K article of circuit.