CN102664835B - Multicell channel estimation method based on interference elimination route by route - Google Patents

Abstract

The invention relates to a multicell channel estimation method based on interference elimination route by route, provides a thought of interference elimination based ona route, and in this thought framework, provides two specific methods which can be used to eliminate interference. After analysis, the multicell channel estimation method based on interference elimination route by route not only can get a channel impulse response with high accuracy, but also has a low computational complexity. Therefore, the method provided by the invention can getthe channel impulse response with high accuracy in the case of low computational complexity, and a good basis for joint detection is provided.

Description

Based on disturb the multi-cell channel estimation method of eliminating by footpath

Technical field

The present invention relates to CDMA mobile telecommunication technical field, be specifically related to a kind of based on disturb the multi-cell channel estimation method of eliminating by footpath.

Background technology

TD-SCDMA (Time Division-Synchronous Code Division Multiple-Access) is one of Third Generation Mobile Communication Technical Standand, adopts time division duplex.TD-SCDMA has adopted many advanced persons' the communication technology, as smart antenna, dynamic channel allocation, joint-detection etc.

In the TD-SCDMA of 3GPP specification system, data are with burst form transmission.Midamble code (being also referred to as training sequence) length is 144chips, is to be inserted in the middle of two 352chips data fields, carries out channel estimating for receiving terminal.In TD-SCDMA system, have the orthogonal but not completely orthogonal basic midamble sequence of 128 standards, they are divided into 32 groups.In each community, in four basic midamble sequences of base station from given group, choose one.Adjacent cell is used accurate orthogonal but not completely orthogonal midamble sequence, and the midamble code of same community different user is to be obtained through cyclic shift by certain basic midamble sequence.In the multi-cell downlink transmitting scene of identical networking, the signal that user side (UE) is received not only comprises the signal that this cell base station sends, and has also comprised the signal that base station, adjacent cell sends.Therefore,, in the time that UE carries out channel estimating, the nonorthogonality of midamble sequence has just caused presence of intercell interference.In like manner, in many cell uplinks transmitting scene of identical networking, the signal that base station end is received not only comprises the signal that this community user sends, and comprise the signal that adjacent cell user sends, in the time that channel estimating is carried out in base station, the nonorthogonality of midamble sequence can cause presence of intercell interference equally.

Traditional Steiner channel estimation methods, can adopt FFT/IFFT to simplify calculating.Due in the time estimating the channel impulse response of a certain community, the signal of other community users is all as white noise processing, and the gross power of Noise and Interference is excessive, has therefore affected the accuracy of channel estimating.Thereby use Steiner algorithm only can obtain the poor channel impulse response of initial accuracy (CIR), but this initial CIR can be used as the input of more accurate channel estimation method.

Parallel interference elimination algorithm based on chip is exactly to use traditional Steiner algorithm to obtain initial CIR, and initial CIR is carried out to noise reduction process.Then the midamble signal of reconstruct adjacent cell, and it is removed in CIR from noise reduction one by one chip.Due to this parallel interference removing method one by one chip carry out, therefore computation complexity is higher.In the traditional joint channel estimation algorithm of another kind, channel estimate matrix is made up of the interference user in adjacent cell, although precision of channel estimation is improved, needs to carry out matrix inversion operation in estimation procedure, and computation complexity is high.

Summary of the invention

The deficiency existing in order to overcome above-mentioned prior art, the object of the present invention is to provide a kind of based on disturb the multi-cell channel estimation method of eliminating by footpath, really realize the multi-cell channel estimation method that a kind of high accuracy, low complex degree are provided, based on disturb the multi-cell channel estimation method of eliminating by footpath.

In order to achieve the above object, the technical solution adopted in the present invention is:

Based on disturb a multi-cell channel estimation method of eliminating by footpath, step is as follows:

Step 1: adopt following formula

$\hat{h}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(e_{\mathrm{mid}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basic}}\right)}\right)$

Obtain the initial cir value of current service cell wherein, e _midrepresent the midamble sequence that receiving terminal is received, m _basicrepresent the basic midamble sequence that community is used;

Step 2: initial CIR is carried out to noise reduction process, select power in initial CIR and exceed the element of setting thresholding, thus the predominating path of separation and Extraction Chu Ge community;

Step 3: adjacent community, current service cell is also adopted successively to the method for step (1) and (2), obtain the CIR of adjacent community after noise reduction process and its predominating path;

Step 4: by footpath eliminate adjacent area interference, and then obtain final CIR.

When the method for the adjacent area interference of described elimination is parallel interference removing method, disturb the step of eliminating as follows:

Step 1: first set the midamble code that current service cell uses and be designated as m ₁, the midamble that adjacent community is used is designated as respectively m ₂, m ₃..., m _n, the predominating path number of current service cell and adjacent community respectively is N ₁, N ₂..., N _n, wherein n is greater than 1 integer;

Step 2: obtain the channel impulse response y that comprises presence of intercell interference, by N=N ₁+ N ₂+ ... + N _nthe individual element composition of selecting, is expressed as:

$y={[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),\·\·\·{,\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),\·\·\·,{\tilde{h}}_2(N_1-1)\·\·\·,{\tilde{h}}_n\left(0\right),{\tilde{h}}_n\left(1\right),\·\·\·,{\tilde{h}}_n(N_1-1)]}^T$

Wherein be followed successively by the predominating path of current service cell and adjacent community, i is more than or equal to 1 integer that is less than or equal to n;

Step 3: obtain the interference matrix B of N × N, B=R-E, matrix R represents the weighing factor matrix between current service cell and adjacent each footpath, minizone, wherein E is unit matrix, R _ijrepresent path to path weighing factor, j is more than or equal to 1 integer that is less than or equal to n, wherein i community to the weighing factor matrix of j community by following formula

$R_{\mathrm{ij}}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basicj}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basici}}\right)}\right)$

Calculate;

Step 4: the initial value β that iteration is set ⁽⁰⁾=y, sets predefine stopping criterion for iteration, comprises maximum iteration time, precision of channel estimation requirement;

Step 5: obtain β according to following iterative formula ^(l), l=0,1

β ^(l)＝y-Bβ ^(l-1),l＝1,2,…,∞.

Step 6: if β ^(l)meet predefined stopping criterion for iteration, iteration finishes, otherwise returns to step (3);

Step 7: by iteration result β ^(l)the predominating path substitution of Zhong Ge community, through in the CIR of noise reduction process, obtains the final CIR eliminating through interference of multiple communities.

When the method for the adjacent area interference of described elimination is method for eliminating serial interference, disturb the step of eliminating as follows:

Step 1: first set the midamble code that current service cell uses and be designated as m ₁, the midamble that adjacent community is used is designated as respectively m ₂, m ₃..., m _n, the predominating path number of current service cell and adjacent community respectively is N ₁, N ₂..., N _n, wherein n is greater than 1 integer;

Step 2: obtain the channel impulse response y that comprises presence of intercell interference, by N=N ₁+ N ₂+ ... + N _nthe individual element composition of selecting, is expressed as:

$y={[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),\·\·\·{,\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),\·\·\·,{\tilde{h}}_2(N_1-1)\·\·\·,{\tilde{h}}_n\left(0\right),{\tilde{h}}_n\left(1\right),\·\·\·,{\tilde{h}}_n(N_1-1)]}^T$

Wherein be followed successively by the predominating path of current service cell and adjacent community, i is more than or equal to 1 integer that is less than or equal to n;

Step 3: the y matrix that in eliminating for parallel interference, step 1 obtains, sorts from big to small and selects power maximum diameter h by power _i, i is more than or equal to 1 integer that is less than or equal to n;

Step 4: obtain the interference matrix B of N × N, B=R-E, matrix R represents the weighing factor matrix between current service cell and adjacent each footpath, minizone, wherein E is unit matrix, R _ijrepresent path to path weighing factor, j is more than or equal to 1 integer that is less than or equal to n, wherein i community to the weighing factor matrix of j community by following formula

$R_{\mathrm{ij}}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basicj}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basici}}\right)}\right)$

Calculate;

Step 5: according to following formula, by footpath eliminate h _ito other footpaths h _jinterference.

h _j→h _j-R _jih _i

Step 6: to the rearrangement of y matrix, remove the footpath of having selected, select power maximum diameter, return to step 4, until all footpaths were all selected in y matrix, obtain the final CIR eliminating through interference of multiple communities.

The thinking that provides a kind of interference based on path to eliminate is provided, under this thinking framework, the concrete grammar that provides two kinds of operable interference to eliminate.By analysis, based on disturbing the multi-cell channel estimation method of eliminating not only can obtain high-precision channel impulse response by footpath, and there is lower computation complexity.Therefore method provided by the invention can, the in the situation that of lower computation complexity, obtain high-precision channel impulse response, and then provides good basis for joint-detection.

Brief description of the drawings

Fig. 1 is TD-SCDMA burst structure.

Fig. 2 is two cell system models.

Embodiment

Below in conjunction with drawings and Examples, the present invention will be described in more detail.

Based on disturb the multi-cell channel estimation method of eliminating by footpath, step is as follows:

Step 1: adopt following formula

$\hat{h}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(e_{\mathrm{mid}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basic}}\right)}\right)$

Obtain the initial cir value of current service cell wherein, e _midrepresent the midamble sequence that receiving terminal is received, m _basicrepresent the basic midamble sequence that community is used;

Step 2: initial CIR is carried out to noise reduction process, select power in initial CIR and exceed the element of setting thresholding, thus the predominating path of separation and Extraction Chu Ge community;

Step 3: adjacent community, current service cell is also adopted successively to the method for step (1) and (2), obtain the CIR of adjacent community after noise reduction process and its predominating path;

Step 4: by footpath eliminate adjacent area interference, and then obtain final CIR.

When the method parallel interference removing method of the adjacent area interference of described elimination, disturb the step of eliminating as follows:

Step 1: first set the midamble code that current service cell uses and be designated as m ₁, the midamble that adjacent community is used is designated as respectively m ₂, m ₃..., m _n, the predominating path number of current service cell and adjacent community respectively is N ₁, N ₂..., N _n, wherein n is greater than 1 integer;

Step 2: obtain the channel impulse response y that comprises presence of intercell interference, by N=N ₁+ N ₂+ ... + N _nthe individual element composition of selecting, is expressed as:

$y={[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),\·\·\·{,\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),\·\·\·,{\tilde{h}}_2(N_1-1)\·\·\·,{\tilde{h}}_n\left(0\right),{\tilde{h}}_n\left(1\right),\·\·\·,{\tilde{h}}_n(N_1-1)]}^T$

Wherein be followed successively by the predominating path of current service cell and adjacent community, i is more than or equal to 1 integer that is less than or equal to n;

Step 3: obtain the interference matrix B of N × N, B=R-E, matrix R represents the weighing factor matrix between current service cell and adjacent each footpath, minizone, wherein E is unit matrix, R _ijrepresent path to path weighing factor, j is more than or equal to 1 integer that is less than or equal to n, wherein i community to the weighing factor matrix of j community by following formula

$R_{\mathrm{ij}}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basicj}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basici}}\right)}\right)$

Calculate;

Step 4: the initial value β that iteration is set ⁽⁰⁾=y, sets predefine stopping criterion for iteration, comprises maximum iteration time, precision of channel estimation requirement;

Step 5: obtain β according to following iterative formula ^(l), l=0,1

β ^(l)＝y-Bβ ^(l-1),l＝1,2,…,∞.

Step 6: if β ^(l)meet predefined stopping criterion for iteration, iteration finishes, otherwise returns to step (3);

Step 7: by iteration result β ^(l)the predominating path substitution of Zhong Ge community, through in the CIR of noise reduction process, obtains the final CIR eliminating through interference of multiple communities.

When the method for the adjacent area interference of described elimination is method for eliminating serial interference, disturb the step of eliminating as follows:

Step 1: first set the midamble code that current service cell uses and be designated as m ₁, the midamble that adjacent community is used is designated as respectively m ₂, m ₃..., m _n, the predominating path number of current service cell and adjacent community respectively is N ₁, N ₂..., N _n, wherein n is greater than 1 integer;

Step 2: obtain the channel impulse response y that comprises presence of intercell interference, by N=N ₁+ N ₂+ ... + N _nthe individual element composition of selecting, is expressed as:

$y={[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),\·\·\·{,\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),\·\·\·,{\tilde{h}}_2(N_1-1)\·\·\·,{\tilde{h}}_n\left(0\right),{\tilde{h}}_n\left(1\right),\·\·\·,{\tilde{h}}_n(N_1-1)]}^T$

Wherein be followed successively by the predominating path of current service cell and adjacent community, i is more than or equal to 1 integer that is less than or equal to n;

Step 3: the y matrix that in eliminating for parallel interference, step 1 obtains, sorts from big to small and selects power maximum diameter h by power _i, i is more than or equal to 1 integer that is less than or equal to n;

Step 4: obtain the interference matrix B of N × N, B=R-E, matrix R represents the weighing factor matrix between current service cell and adjacent each footpath, minizone, wherein E is unit matrix, R _ijrepresent path to path weighing factor, j is more than or equal to 1 integer that is less than or equal to n, wherein i community to the weighing factor matrix of j community by following formula

$R_{\mathrm{ij}}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basicj}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basici}}\right)}\right)$

Calculate;

Step 5: according to following formula, by footpath eliminate h _ito other footpaths h _jinterference.

h _j→h _j-R _jih _i

Step 6: to the rearrangement of y matrix, remove the footpath of having selected, select power maximum diameter, return to step 4, until all footpaths were all selected in y matrix, obtain the final CIR eliminating through interference of multiple communities.

Taking two cell pattern shown in Fig. 2 as example, wherein, the applicable midamble code in current service cell is m particularly ₁, the midamble that adjacent cell is used is m ₂.Supposing has 4 users in current service cell, also there are 4 users adjacent service community.In a certain time slot, maximum number of user is 8 (K _cell=8), the length of CIR is 16 (W=16).M.1225, under the Pedestrian A (PedA) defining at Rec.ITU-R respectively and two kinds of channels of Vehicular A (VehA), adopt based on disturb the multi-cell channel estimation method of eliminating by footpath.The channel parameter of two kinds of channels is as shown in table 1.Other parameter of simulating scenes is as shown in table 2.

Table 1

Table 2

Parameter	Value
		Noise?Power	-104dBm
Noise?Figure	9dB
		NodeB?Power	34dBm
PhyCH?Power	22dBm

Antenna?Gain	11dB
		Cell?Radius	866m

Suppose that the predominating path number of current service cell is N through extracting ₁, the predominating path number of adjacent cell is N ₂.

Adopt parallel interference removing method to disturb elimination, step is as follows:

(1) obtain the channel impulse response y that comprises presence of intercell interference, by N ₁+ N ₂the individual element of selecting can be expressed as:

$y={[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),\·\·\·{,\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),\·\·\·,{\tilde{h}}_2(N_1-1)]}^T$

Wherein for the predominating path of Serving cell, for the predominating path of adjacent cell.

(2) obtain (N ₁+ N ₂) × (N ₁+ N ₂) interference matrix B, B=R-E.Matrix R represents the weighing factor between each footpath, minizone, wherein r _ijrepresent the weighing factor of path j to path i.Because only exist presence of intercell interference, and there is no the interference in community.Therefore the diagonal blocks N in R matrix ₁× N ₁matrix and N ₂× N ₂matrix except diagonal entry be 1, other elements are 0.Contrary diagonal piece represents respectively the weighing factor matrix R of Serving cell to adjacent cell ₁₂and the weighing factor matrix R of adjacent cell to Serving cell ₂₁, following formula calculates respectively.

$R_{12}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basic}2}\right)}{\mathrm{FFT}\left(m_{\mathrm{basic}1}\right)}\right)$

$R_{21}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basic}1}\right)}{\mathrm{FFT}\left(m_{\mathrm{basic}2}\right)}\right)$

(3) the initial value β of iteration is set ⁽⁰⁾=y, sets predefine stopping criterion for iteration, as maximum iteration time, and precision of channel estimation requirement etc.

(4) obtain β according to the iterative formula in parallel interference removal process (4) ^(l), l=0,1 ...

(5) if β ^(l)meet predefined stopping criterion for iteration, iteration finishes, otherwise returns to step (4)

(6) by iteration result β ^(l)in before N ₁in the CIR of the Serving cell of the substitution process noise reduction process that individual element is corresponding, obtain the final CIR of Serving cell.In like manner, by iteration result β ^(l)in after N ₂in the CIR of the adjacent cell of the substitution process noise reduction process that individual element is corresponding, obtain the final CIR of adjacent cell.

Adopt method for eliminating serial interference to disturb elimination, step is as follows:

(1) for the y matrix that in parallel interference elimination, step 1 obtains, sort from big to small by power; ,

(2) select power maximum diameter h _i

(3) eliminated by parallel interference in the R matrix that obtains of step 2, according to the formula in serial interference elimination step (3), by footpath eliminate h _ito other footpaths h _jinterference.

(4) to the rearrangement of y matrix, remove the footpath of having selected, select power maximum diameter, return to step 3, until all footpaths were all selected in y matrix.

Adopt MSE (mean square error) and correlation coefficient ρ to weigh the precision of channel estimating in this scheme.

Wherein

$\mathrm{mse}=\sqrt{E\left({(\hat{h}-h)\·}^2\right)}$

$\mathrm{\ρ}=\left|\frac{\mathrm{cov}(\hat{h},h)}{\sqrt{\mathrm{cov}(\hat{h},h)\mathrm{cov}(h,h)}}\right|.$

The thought that provides a kind of interference based on path to eliminate is provided, under this thought frame, provides two kinds by the elimination of footpath parallel interference with by footpath method for eliminating serial interference.Through simulation analysis, based on disturbing the multi-cell channel estimation method of eliminating not only can improve the accuracy of channel estimating by footpath, and with compare by chip interference elimination method, ZF integrated processes and least mean-square error unified algorithm, there is lower computation complexity.Therefore method provided by the invention can, the in the situation that of low computation complexity, obtain high-precision channel impulse response, and then provides good basis for joint-detection.

Claims (2)

1. based on disturb a multi-cell channel estimation method of eliminating by footpath, it is characterized in that, step is as follows:

Step 1: adopt following formula

$\hat{h}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(e_{\mathrm{mid}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basic}}\right)}\right)$

Obtain the initial cir value of current service cell wherein, e _midrepresent the midamble sequence that receiving terminal is received, m _basicrepresent the basic midamble sequence that community is used;

Step 2: initial CIR is carried out to noise reduction process, select power in initial CIR and exceed the element of setting thresholding, thus the predominating path of separation and Extraction Chu Ge community;

Step 3: adjacent community, current service cell is also adopted successively to the method for step 1 and 2, obtain channel impulse response (CIR) and its predominating path of adjacent community after noise reduction process;

Step 4: by footpath eliminate adjacent area interference, and then obtain final CIR;

The method of the adjacent area interference of described elimination is that parallel interference removing method disturbs elimination, and step is as follows:

Step 4.1: first set the midamble code that current service cell uses and be designated as m ₁, the midamble that adjacent community is used is designated as respectively m ₂, m ₃..., m _n, the predominating path number of current service cell and adjacent community respectively is N ₁, N ₂..., N _n, wherein n is greater than 1 integer;

Step 4.2: obtain the channel impulse response y that comprises presence of intercell interference, by N=N ₁+ N ₂+ ... + N _nthe individual element composition of selecting, is expressed as:

$y=[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),...,{\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),...,{\tilde{h}}_2(N_2-1)...,{\tilde{h}}_n\left(0\right),{\tilde{h}}_n\left(1\right),...{\tilde{h}}_n(N_n-1){]}^T$

Wherein be followed successively by the predominating path of current service cell and adjacent community, i is more than or equal to 1 integer that is less than or equal to n;

Step 4.3: obtain the interference matrix B of N × N, B=R-E, matrix R represents the weighing factor matrix between current service cell and adjacent each footpath, minizone, wherein E is unit matrix, R _ijrepresent path to path weighing factor, j is more than or equal to 1 integer that is less than or equal to n, wherein i community to the weighing factor matrix of j community by following formula

$R_{\mathrm{ij}}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basicj}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basici}}\right)}\right)$

Calculate;

Step 4.4: the initial value β that iteration is set ⁽⁰⁾=y, sets predefine stopping criterion for iteration, comprises maximum iteration time, precision of channel estimation requirement;

Step 4.5: obtain β according to following iterative formula ^(l), l=0,1

β ^(l)＝y-Bβ ^(l-1),l＝1,2,…,∞.

Step 4.6: if β ^(l)meet predefined stopping criterion for iteration, iteration finishes, otherwise returns to step 4.3;

Step 4.7: by iteration result β ^(l)the predominating path substitution of Zhong Ge community, through in the CIR of noise reduction process, obtains the final CIR eliminating through interference of multiple communities.

2. based on disturb a multi-cell channel estimation method of eliminating by footpath, it is characterized in that, step is as follows:

Step 1: adopt following formula

$\hat{h}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(e_{\mathrm{mid}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basic}}\right)}\right)$

Obtain the initial cir value of current service cell wherein, e _midrepresent the midamble sequence that receiving terminal is received, m _basicrepresent the basic midamble sequence that community is used;

Step 2: initial CIR is carried out to noise reduction process, select power in initial CIR and exceed the element of setting thresholding, thus the predominating path of separation and Extraction Chu Ge community;

Step 3: adjacent community, current service cell is also adopted successively to the method for step 1 and 2, obtain channel impulse response (CIR) and its predominating path of adjacent community after noise reduction process;

Step 4: by footpath eliminate adjacent area interference, and then obtain final CIR;

The method of the adjacent area interference of described elimination is for adopting method for eliminating serial interference to disturb elimination, and step is as follows:

Step 4.1: first set the midamble code that current service cell uses and be designated as m ₁, the midamble that adjacent community is used is designated as respectively m ₂, m ₃..., m _n, the predominating path number of current service cell and adjacent community respectively is N ₁, N ₂..., N _n, wherein n is greater than 1 integer;

Step 4.2: obtain the channel impulse response y that comprises presence of intercell interference, by N=N ₁+ N ₂+ ... + N _nthe individual element composition of selecting, is expressed as:

$y=[{\tilde{h}}_1\left(0\right),{\tilde{h}}_1\left(1\right),...,{\tilde{h}}_1(N_1-1),{\tilde{h}}_2\left(0\right),{\tilde{h}}_2\left(1\right),...,{\tilde{h}}_2(N_2-1)...,{\tilde{h}}_n\left(0\right),{\tilde{h}}_n\left(1\right),...{\tilde{h}}_n(N_n-1){]}^T$

Wherein be followed successively by the predominating path of current service cell and adjacent community, i is more than or equal to 1 integer that is less than or equal to n;

Step 4.3: for the y matrix obtaining in parallel interference removal process 4.2, sort from big to small and select power maximum diameter h by power _i, i is more than or equal to 1 integer that is less than or equal to n;

Step 4.4: obtain the interference matrix B of N × N, B=R-E, matrix R represents the weighing factor matrix between current service cell and adjacent each footpath, minizone, wherein E is unit matrix, R _ijrepresent path to path weighing factor, j is more than or equal to 1 integer that is less than or equal to n, wherein i community to the weighing factor matrix of j community by following formula

$R_{\mathrm{ij}}=\mathrm{IFFT}\left(\frac{\mathrm{FFT}\left(m_{\mathrm{basicj}}\right)}{\mathrm{FFT}\left(m_{\mathrm{basici}}\right)}\right)$

Calculate;

Step 4.5: according to following formula, by footpath eliminate h _ito other footpaths h _jinterference;

h _j→h _j-R _jih _i

Step 4.6: to the rearrangement of y matrix, remove the footpath of having selected, select power maximum diameter, return to step 4.4, until all footpaths were all selected in y matrix, obtain the final CIR eliminating through interference of multiple communities.