CN1949682B - Method and apparatus for cancellation eliminating common-frequency cell signal interference based on serial interference - Google Patents

Abstract

The invention provides a serial interference offset-based same-frequency cell signal interference eliminating method and device, for each cell, superposing the reconstructed signal of the cell in the previous-stage interference eliminating course and the residual signal obtained after removing all cell interfering signals in the current-stage interference eliminating course, and restoring the received signal of the cell; then reconstructing cell interfering signal by the demodulation symbol generated, based on combined detection; removing the reconstructed signal of the cell in the current-stage interference eliminating course from the input signal and obtaining the residual signal; according to serial progression, repeating executing the above steps. And the invention can eliminate the influence of same-frequncy cell signals and improve the signal receving performance of the cell on the mal-condition that the powers of the adjacent same-frequency cells are higher than that of the cell.

Description

Eliminate the method and apparatus that common-frequency cell signal disturbs based on counteracting serial interference

Technical field

The present invention relates to a kind of TD SDMA (Time Division SynchronousCode-Division Multiple Access that is used for, abbreviation TD-SCDMA) method and apparatus of co-channel interference is eliminated in the serial of mobile communication system, specifically, relate to a kind of serial to greatest extent and eliminate of the influence of co-channel interference signal, improve the method and apparatus of receiver receptivity useful signal.

Background technology

In Direct-Spread code division multiple access (the being called for short DS-CDMA) system, owing to adopted CDMA (Code Division Multiple Access), objectively exist different districts to adopt the possibility of identical networking, this just means that certain base station (NodeB) may be subjected to the interference of travelling carriage (UE) signal in a plurality of co-frequency neighbor cells, and perhaps certain travelling carriage may be subjected to the interference of a plurality of co-frequency cell base station signals.Because the propagation delay difference of unlike signal, and the existence of scrambler, the spreading code set that causes each signal to adopt not is complete quadrature, and this interference that is caused by the non-zero cross-correlation coefficient often is called as multiple access and disturbs (Multiple Access Interference is called for short MAI).Common matched filter (Matched Filter is called for short MF, and traditional Rake receiver just meets the MF principle) or the multi-user detection device (Multi-user Detector is called for short MUD) of adopting recovers spread spectrum and adds around preceding data in the cdma system.Traditional Rake receiver can't effectively suppress multiple access to be disturbed, and Multiuser Detection can be eliminated the influence that MAI brings preferably.

Multi-user test method mainly is divided into two kinds: linear multi-user detects and non-linear Multiuser Detection.Linear multi-user detects (joint detection receiver) owing to need finish the operation that sytem matrix is inverted, spreading factor (Spread Factor when the cdma system employing, when abbreviation SF) big, scrambler length quantity long or interference user is too many, the dimension of sytem matrix will increase, and the operand of matrix inversion will become and can't accept.In this case, non-linear multi-user test method (Interference Cancellation) can obtain receptivity preferably with lower implementation complexity.Non-line multi-user test method mainly is divided into two kinds: parallel interference is eliminated (Parallel Interference Cancellation is called for short PIC) and serial interference elimination (Successive Interference Cancellation is called for short SIC).By contrast, it is short that PIC has the time-delay handled, and do not need each sub-district carried out advantages such as power ordering; And the resource that SIC consumes still less, and stability is better when each cell signal difference power distance is big, performance is better.

As scheme shown in the l, be the frame structure schematic diagram of TD-SCDMA system.This structure is according to low spreading rate time division duplex (LCR-TDD) pattern (1.28Mcps) among 3G collaborative project (3GPP) the standard TS 25.221 (Release 4), perhaps provides among China Wireless Telecommunication Standar (CWTS) standard TSM 05.02 (Release3).The spreading rate of TD-SCDMA system is 1.28Mcps, each radio frames (RadioFrame) 10 ₀, 10 ₁Length be 5ms, i.e. 6400 chips (for 3GPP LCR-TDD system, each radio frames length is 10ms, and the subframe (Subframe) that can be divided into two length be 5ms, and wherein each subframe comprises 6400 chips).Wherein, the radio frames in each TD-SCDMA system (the perhaps subframe in the LCR system) 10 ₀, 10 ₁(TS0～TS6) 11 can be divided into 7 time slots again ₀-11 ₆, and two pilot time slots: descending pilot frequency time slot (DwPTS) 12 and uplink pilot time slot (UpPTS) 14, and protection interval (Guard) 13.Further, the TS0 time slot 11 ₀Be used to bearing system broadcast channel and other possible downlink traffic channel; And TS1～TS6 time slot 11 ₁-11 ₆Then be used to carry the uplink and downlink Traffic Channel.It is synchronous that uplink pilot time slot (UpPTS) 14 and descending pilot frequency time slot (DwPTS) time slot 12 are used to set up initial uplink and downlink respectively.TS0～TS6 time slot 11 ₀-11 ₆Length is 0.675ms or 864 chips, wherein comprises data segment DATA1 (17) and DATA2 (19) that two segment length are 352 chips, and a middle segment length is the training sequence of 144 chips (chip)---in lead sign indicating number (Midamble) sequence 18.The Midamble sequence is significant at TD-SCDMA, comprise cell ID, channel estimating and synchronously modules such as (comprising Frequency Synchronization) all to use it.DwPTS time slot 12 comprises 20 and descending synchronous code (SYNC-DL) code words 15 that length is 64 chips in protection interval of 32 chips, and its effect is cell ID and sets up initial synchronisation; And UpPTS time slot uplink synchronous code (SYNC-UL) code word 16 that to comprise a length be 128 chips, subscriber terminal equipment utilizes it to carry out relevant up access procedure.

Two parts data segment DATA1 (17) of TD-SCDMA descending time slot and DATA2 (19) institute data carried by data adopt spreading code and scrambler to carry out spread spectrum and add around.Under the situation that has co-channel interference, because spreading code (Spreading Code) and scrambler (Scrambling Code) length that the TD-SCDMA system adopts are all relatively lacked (all having only 16chip), the spreading code and the their cross correlation between the scrambler of different districts are undesirable, joint-detection device (the Joint Detection of traditional Rake receiver or single sub-district, be called for short JD) can't effectively suppress the influence of adjacent cell interfering signal, caused the deterioration of TD-SCDMA system receptivity.In order to make the TD-SCDMA system obtain the higher system capacity, must improve its receptivity under co-channel interference.The present invention introduces the method for counteracting serial interference, effectively raises under the co-channel interference condition receptivity of TD-SCDMA system.

Summary of the invention

The object of the present invention is to provide a kind of method and apparatus of eliminating the common-frequency cell signal interference based on counteracting serial interference, can be with less implementation complexity, to a great extent, particularly co-frequency neighbor cell power is higher than under the mal-condition of this sub-district, eliminate the influence of common-frequency cell signal, improve the receptivity of this cell signal.

The invention provides a kind of method of eliminating the common-frequency cell signal interference based on counteracting serial interference, characteristics are, this sub-district and each co-frequency neighbor cell adopt the method for each cell signal of demodulation symbol reconstruct that produces based on joint-detection respectively separately, interference eliminated is carried out in serial, and it may further comprise the steps:

Step 1, to each sub-district, promptly current this sub-district and M co-frequency neighbor cell, sub-district received signal recovery unit is with the reconstruction signal of this sub-district in the s-1 level interference cancellation process With the residual signal after all cell interfering signal before the removal in the s level interference cancellation process

Stack recovers the received signal of each sub-district

${\hat{e}}_j^s={\hat{r}}_{j-1}^s+{\hat{x}}_j^{s-1}$

Wherein, s=1,2 ..., S, and S represents the progression of the counteracting serial interference of default;

j＝1，2，…，M，M+1；

Step 2, according to the sampling on current reception data I/Q road input

With the signal sum after the s-1 level interference eliminated, channel estimating and interference reconstruction unit (Channel Estimation andInterference Generation Unit, abbreviation CEIGU) employing is based on the method for each cell signal of demodulation symbol reconstruct of joint-detection (JD) generation, the reconstruct of each sub-district received signal is finished in serial successively, obtains the reconstruction signal of each sub-district of s level:

${\hat{x}}_j^s=(x_{(j,1)}^s,x_{(j,2)}^s,...,x_{(j,Z)}^s);$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1, Z are the length of sample sequence;

This step 2 specifically comprises:

Step 2.1, active path separate;

Step 2.2, generation channel impulse response;

Step 2.3, produce demodulation symbol, comprising based on joint-detection:

Step 2.4, reconstruct cell signal;

Step 3, to each sub-district, the sub-district reconstruction signal is removed the unit successively with the reconstruction signal of this sub-district in the s level interference cancellation process From input signal In remove, obtain the residual signal after this area interference of removal of s level

${\hat{r}}_j^s={\hat{e}}_j^s-{\hat{x}}_j^s;$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1;

Step 4, according to the SIC progression that system is provided with in advance, repeated execution of steps 1～3 is up to the SIC operation of finishing all grades.

In the described step 1, when s=1, promptly carry out first order interference eliminated, the reconstruction signal of this sub-district is made as 0.

In the described step 1, when j=1, promptly carry out the interference eliminated of first sub-district, the residual signal before removing in the then described interference cancellation process after all cell interfering signal is 0.

Employing described in the step 2 specifically comprises based on the method for the demodulation symbol reconstruct cell signal of joint-detection generation:

Step 2.1, active path separate;

Step 2.1.1, at each sub-district, with back 128 chip data of the middle guiding code sequence in the input signal (Midamble sign indicating number) part

By matched filter, respectively with basic middle guiding code sequence (Basic Midamble) BM=(m of this sub-district ₁, m ₂..., m ₁₂₈) pursue bit circulation xor operation, calculate the each power (DelayProfile is called for short DP) on each path by bit XOR result:

${\mathrm{DP}}_k=\underset{n=1}{\overset{128}{\mathrm{\Σ}}}\left|\right|r_n^{\mathrm{BM}}*m_{(n-k+1)\mathrm{mod}128}\left|\right|;$

Step 2.1.2, detect active path by the active path detector:

Power DP on each path (Path) and certain threshold Th are compared; Selection is an active path more than or equal to the pairing path of power DP of thresholding Th, otherwise is invalid path; The final detected L bar of active path detector active path is: P _Eff=(p ₁, p ₂..., p _L);

Step 2.2, generation channel impulse response (Channel Impulse):

Step 2.2.1, calculate channel estimating on each path (Channel Estimation is called for short ChE) by matched filter and channel estimator:

Basic middle guiding code sequence according to current area is BM=(m ₁, m ₂..., m ₁₂₈), and the data of back 128 chips of the part of the middle guiding code sequence in the input signal that receives are

The channel estimating ChE that calculates on each path is:

${\mathrm{ChE}}_k=\underset{n=1}{\overset{128}{\mathrm{\Σ}}}{r}_n^{\mathrm{BM}}*m_{(n-k+1)\mathrm{mod}128};$

Step 2.2.2, according to the channel estimating that obtains among active path that obtains among the step 2.1.2 and the step 2.2.1, generate channel impulse response H=(h by the channel impulse response device ₁, h ₂..., h _T), its length T is represented the maximum delay that system supports, and the locational value of this channel impulse response active path is the channel estimation value on this path, and the locational value of non-active path is zero, that is:

$h_i=\left\{\begin{array}{cc}{\mathrm{ChE}}_i& {\mathrm{DP}}_i\&GreaterEqual;\mathrm{Th}\\ 0& {\mathrm{DP}}_i<\mathrm{Th}\end{array}\right.;$

Step 2.3, produce demodulation symbol based on joint-detection:

Step 2.3.1, the data division in the input signal is carried out descrambling, de-spreading operation by matched filter:

According to the position P of active path, the scrambler ScC of current area and the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, adopts matched filter to the data division in the input signal

Carry out descrambling, de-spreading operation, the symbol that obtains after descrambling, the despreading is:

$U=({\hat{u}}^1,{\hat{u}}^2,...,{\hat{u}}^N);$

${\hat{u}}^n=({\hat{u}}_1^n,{\hat{u}}_2^n,...,{\hat{u}}_L^n);$

${\hat{u}}_l^n=(u_{(l,1)}^n,u_{(l,2)}^n,...,u_{(l,K)}^n);$

$u_{(l,k)}^n=\underset{i=1}{\overset{\mathrm{SF}}{\mathrm{\&Sigma;}}}{r}_{p_k+(k-1)\&CenterDot;\mathrm{SF}+i}\&times;\mathrm{conj}\left(c_i^n\right)\&times;\mathrm{conj}\left({\mathrm{ScC}}_i\right);$

Wherein,

Represent n the pairing symbol of activated code channel,

Represent n the symbol on the activated code channel l bar active path, K represents the number of symbol, u _{(l, k)} ⁿThe symbol of representing n activated code channel of the 1st k symbol of active path;

Step 2.3.2, the symbol that is obtained after to descrambling, despreading by maximal ratio combiner carry out high specific and merge, and obtain demodulation symbol:

According to channel impulse response, i.e. channel estimating on the active path, maximal ratio combiner carries out the high specific union operation to the descrambling on the different paths, symbol after the despreading, obtains the demodulation symbol on each activated code channel:

$Y=({\hat{y}}^1,{\hat{y}}^2,...,{\hat{y}}^N);$

${\hat{y}}^n=(y_1^n,y_2^n,...,y_K^n);$

$y_k^n=\underset{l=1}{\overset{L}{\mathrm{\&Sigma;}}}\mathrm{conj}\left({\mathrm{ChE}}_l\right)\&times;u_{(l,k)}^n;$

Wherein,

Represent n the pairing demodulation symbol of activated code channel, u _{(l, k)} ⁿThe symbol of representing n activated code channel of the 1st k symbol of active path;

Step 2.3.3, joint-detection:

Dot product result and the channel impulse response of the scrambler that step 2.3.3.1, sytem matrix maker adopt according to current area, the spreading code of activation carry out convolution, generation sytem matrix (System ResponseMatrix):

According to the scrambler ScC of the current area that generates by scrambling code generator and spreading code maker, the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, and by the channel impulse response H that obtains among the step 2.2.2, calculates sytem matrix A by the sytem matrix maker:

$b^n=H\&CircleTimes;(\mathrm{ScC}.*C_n);$

B＝[b ¹，b ²，…，b ^N] ^T；

Wherein, [] ^TThe representing matrix transposition, the number of the B matrix in the A matrix need to equal the symbol numbers of joint-detection;

Step 2.3.3.2, combined detector adopt ZF linear block balance device algorithm (Zero-ForcingBlock Linear Equalizer, be called for short ZF-BLE) or minimum Mean Square Error Linear block equalizers algorithm (Minimum Mean Square Error Block Linear Equalizer, be called for short MMSE-BLE) carry out the joint-detection operation, obtain demodulation symbol;

Adopt described ZF linear block balance device algorithm, the demodulation symbol that obtains is:

$\hat{d}={(A^H\&CenterDot;A)}^{-1}\&CenterDot;A^H\&CenterDot;\hat{r};$

Wherein, A represents sytem matrix, The I/Q road signal of expression input,

The demodulation symbol that the expression joint-detection obtains.

Adopt described minimum Mean Square Error Linear block equalizers algorithm, the demodulation symbol that obtains is:

$\hat{d}={(A^H\&CenterDot;A+{\mathrm{\&sigma;}}^2\&CenterDot;I)}^{-1}\&CenterDot;A^H\&CenterDot;\hat{r};$

Wherein, A represents sytem matrix, The I/Q road signal of expression input, σ ²The expression noise variance,

The demodulation symbol that the expression joint-detection obtains, I represents diagonal matrix.

Step 2.3.4, symbol judgement device carry out symbol judgement to the demodulation symbol that is produced by combined detector, and the estimated value that obtains sending symbol is:

$D=({\hat{d}}^1,{\hat{d}}^2,...,{\hat{d}}^N);$

${\hat{d}}^n=(d_1^n,d_2^n,...,d_K^n);$

Wherein

The court verdict of representing n the pairing demodulation symbol of activated code channel.

Among the step 2.3.4, described symbol judgement comprises hard decision and soft-decision:

Described hard decision is operated by demodulation symbol hard decision device, and the result who obtains behind the hard decision is:

$d_k^n=\mathrm{sign}\left(y_k^n\right)=\left\{\begin{array}{cc}1& y_k^n\&GreaterEqual;0\\ -1& y_k^n<0\end{array}\right.;$

Described soft-decision is operated by demodulation symbol soft-decision device, and the result who obtains behind the soft-decision is:

$d_k^n=\tanh \left(\frac{m\&CenterDot;y_k^n}{{\mathrm{\&sigma;}}^2}\right);$

Wherein, m represents the average of received signal amplitude, σ ²The noise variance of expression received signal, tanh represents hyperbolic tangent function.

Step 2.4, reconstruct cell signal:

Step 2.4.1, the result of symbol judgement is modulated the spread spectrum operation, obtains the chip sequence on the activated code channel by the modulation frequency multiplier:

Scrambler ScC, the spread spectrum codes C hC=(C on the activated code channel according to the current area employing ₁, C ₂..., C _N),

Result to symbol judgement modulates and spread spectrum by the modulation frequency multiplier, obtains the estimated value that transmits of chip-level on each activated code channel:

$V=({\hat{v}}^1,{\hat{v}}^2,...,{\hat{v}}^N);$

${\hat{v}}^n=(v_1^n,v_2^n,...,v_{K\&times;\mathrm{SF}}^n);$

Wherein

The estimated value that transmits of representing n the chip-level on the activated code channel;

Step 2.4.2, finish the reconstruct of acknowledge(ment) signal on some activated code channels by the acoustic convolver correspondence:

By acoustic convolver the channel impulse response that obtains in chip sequence on each activated code channel that obtains among the step 2.4.1 and the step 2.2 is finished convolution operation, obtains the reconstruction signal on each activated code channel:

$W=({\hat{w}}^1,{\hat{w}}^2,...,{\hat{w}}^N);$

${\hat{w}}^n=(w_1^n,w_2^n,...,w_{K\&times;\mathrm{SF}}^n);$

${\hat{w}}^n=H\&CircleTimes;{\hat{v}}^n;$

Wherein,

Represent n the reconstruction signal on the code channel,

The estimated value that transmits of representing n the chip-level on the activated code channel;

Step 2.4.3, the reconstruction signal on each activated code channel is superposeed, finish activated code channel and merge, thereby finish the reconstruct of cell signal, obtain the reconstruction signal of sub-district by activated code channel signal superimposer

${\hat{x}}^s=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\hat{w}}^n$

Represent n the reconstruction signal on the code channel;

Step 2.4.4, reconstruction signal weighting: with this sub-district reconstruction signal

Multiply by specific weighted factor ρ ^s, reduce because the incorrect performance loss that causes of symbol judgement:

${\hat{x}}^s={\hat{x}}^s\&times;{\mathrm{\&rho;}}^s.$

In this method, when respectively each co-frequency neighbor cell being carried out signal reconstruction, the basic cell information of required current co-frequency neighbor cell comprises basic middle guiding code sequence, and the spreading code of scrambler and activation etc. is that system is known, or obtain by detection.

Corresponding with said method, the present invention also provides a kind of and eliminates the device that common-frequency cell signal disturbs based on counteracting serial interference (SIC), and described device comprises the sub-district received signal recovery unit that connects successively, removes the unit based on CEIGU and the sub-district reconstruction signal of JD;

Described sub-district received signal recovery unit is successively for current this sub-district and M co-frequency neighbor cell, with the reconstruction signal of this sub-district in the s-1 level interference cancellation process With the residual signal after all cell interfering signal before the removal in the s level interference cancellation process Stack recovers the received signal of each sub-district successively

${\hat{e}}_j^s={\hat{r}}_{j-1}^s+{\hat{x}}_j^{s-1}$

Wherein, s=1,2 ..., S, and S represents the progression of the counteracting serial interference of default; J=1,2 ..., M, M+1.

When s=1, promptly carry out first order interference eliminated, the reconstruction signal of this sub-district is made as 0.

When j=1, promptly carry out the interference eliminated of first sub-district, the residual signal before removing in the then described interference cancellation process at the corresponding levels after all cell interfering signal is 0.

Described CEIGU based on JD is according to the sampling input on current reception data I/Q road With the signal sum after the s-1 level interference eliminated, adopt the processing method of the demodulation symbol reconstruct cell signal that produces based on JD, the reconstruct of each sub-district received signal is finished in serial successively, obtains the reconstruction signal of each sub-district of s level:

${\hat{x}}_j^s=(x_{(j,1)}^s,x_{(j,2)}^s,...,x_{(j,Z)}^s);$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1, Z are the length of sample sequence.

Described CEIGU based on JD comprises the active path separator that connects by circuit, channel impulse response device, based on the demodulation symbol generating apparatus and the cell signal reconfiguration device of joint-detection;

Described sub-district reconstruction signal is removed the unit to each sub-district, successively with the reconstruction signal of this sub-district in the s level interference cancellation process

From input signal

In remove, obtain the residual signal after this area interference of removal of s level

${\hat{r}}_j^s={\hat{e}}_j^s-{\hat{x}}_j^s;$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1.

Described active path separator comprises first matched filter and the active path detector that connects successively;

Back 128 chip data BM=(m of the middle guiding code sequence in the input receiving inputted signal of this first matched filter ₁, m ₂..., m ₁₂₈), with the basic middle guiding code sequence of current area

Pursue bit circulation xor operation, calculate each power by bit XOR result:

${\mathrm{DP}}_k=\underset{n=1}{\overset{128}{\mathrm{\&Sigma;}}}\left|\right|r_n^{\mathrm{BM}}*m_{(n-k+1)\mathrm{mod}128}\left|\right|;$

This active path detector compares the power DP value on each path of first matched filter output respectively with certain threshold Th; Selection is an active path more than or equal to the pairing path of power DP of thresholding Th, otherwise is invalid path; The final detected L bar of active path detector active path is: P _Eff=(p ₁, p ₂..., p _L).

Described channel impulse response device comprises second matched filter, channel estimator and the channel impulse response device that connects successively;

Back 128 chip data BM=(m of the middle guiding code sequence in the input receiving inputted signal of this second matched filter ₁, m ₂..., m ₁₂₈), in conjunction with the basic middle guiding code sequence of current area

The channel estimating ChE that calculates on each path by channel estimator is:

${\mathrm{ChE}}_k=\underset{n=1}{\overset{128}{\mathrm{\&Sigma;}}}{r}_n^{\mathrm{BM}}*m_{(n-k+1)\mathrm{mod}128};$

The input of this channel impulse response device also connects the output of effective path detector; Described channel impulse response device generates channel impulse response H=(h according to active path and channel estimating ₁, h ₂..., h _T):

$h_i=\left\{\begin{array}{cc}{\mathrm{ChE}}_i& {\mathrm{DP}}_i\&GreaterEqual;\mathrm{Th}\\ 0& {\mathrm{DP}}_i<\mathrm{Th}\end{array}\right.;$

Wherein, the length T of channel impulse response is represented the maximum delay that system supports.

Described demodulation symbol generating apparatus based on joint-detection comprises the 3rd matched filter, maximal ratio combiner, joint-detection device and the symbol judgement device that connects successively;

Data division in the input receiving inputted signal of the 3rd matched filter, and be connected with the active path detector, described the 3rd matched filter is according to the position P of active path, the scrambler ScC of current area and the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N), Wherein N represents the number of activated code channel, and SF represents spreading factor, to the data division in the input signal

Carry out descrambling, de-spreading operation, the symbol that obtains after descrambling, the despreading is:

$U=({\hat{u}}^1,{\hat{u}}^2,...,{\hat{u}}^N);$

${\hat{u}}^n=({\hat{u}}_1^n,{\hat{u}}_2^n,...,{\hat{u}}_L^n);$

${\hat{u}}_l^n=(u_{(l,1)}^n,u_{(l,2)}^n,...,u_{(l,K)}^n);$

$u_{(l,k)}^n=\underset{i=1}{\overset{\mathrm{SF}}{\mathrm{\&Sigma;}}}{r}_{p_k+(k-1)\&CenterDot;\mathrm{SF}+i}\&times;\mathrm{conj}\left(c_i^n\right)\&times;\mathrm{conj}\left({\mathrm{ScC}}_i\right);$

Wherein

Represent n the pairing symbol of activated code channel,

Represent n the symbol on the activated code channel l bar active path, K represents the number of symbol;

The input of this maximal ratio combiner is connecting channel impulse response device also, it is according to channel impulse response, it is the channel estimating on the active path, descrambling on the different paths of the 3rd matched filter output, the symbol after the despreading are carried out the high specific union operation, obtain the demodulation symbol on each activated code channel:

$Y=({\hat{y}}^1,{\hat{y}}^2,...,{\hat{y}}^N);$

${\hat{y}}^n=(y_1^n,y_2^n,...,y_K^n);$

$y_k^n=\underset{l=1}{\overset{L}{\mathrm{\&Sigma;}}}\mathrm{conj}\left({\mathrm{ChE}}_l\right)\&times;u_{(l,k)}^n;$

Wherein,

Represent n the pairing demodulation symbol of activated code channel, The symbol of representing n activated code channel of the 1st k symbol of active path;

This joint-detection device comprises scrambling code generator and spreading code maker, sytem matrix maker and the combined detector that connects successively;

The scrambler ScC of the current area that described scrambling code generator and spreading code maker generate, and the spread spectrum codes C hC=(C that activates ₁, C ₂..., C _N), Wherein N represents the number of activated code channel, and SF represents spreading factor;

The input of described sytem matrix maker is the output of connecting channel impulse response device also, it is according to scrambler ScC, the spread spectrum codes C hC of activation of the current area that is generated by scrambling code generator and spreading code maker, and, calculate sytem matrix A by the channel impulse response H that the channel impulse response device generates:

$b^n=H\&CircleTimes;(\mathrm{ScC}.*C_n);$

B＝[b ¹，b ²，…，b ^N] ^T；

Wherein, [] ^TThe representing matrix transposition, the number of the B matrix in the A matrix need to equal the symbol numbers of joint-detection;

The input of described combined detector is connected system matrix maker and maximal ratio combiner respectively; Adopt ZF linear block balance device algorithm or minimum Mean Square Error Linear block equalizers algorithm to carry out the joint-detection operation, obtain demodulation symbol

Described combined detector adopts ZF linear block balance device algorithm, detects the demodulation symbol that obtains and is:

$\hat{d}={(A^H\&CenterDot;A)}^{-1}\&times;A^H\&CenterDot;\hat{r};$

Wherein, A represents sytem matrix,

The I/Q road signal of expression input,

The demodulation symbol that the expression joint-detection obtains.

Described combined detector adopts minimum Mean Square Error Linear block equalizers algorithm, detects the demodulation symbol that obtains to be:

$\hat{d}={(A^H\&CenterDot;A+{\mathrm{\&sigma;}}^2\&CenterDot;I)}^{-1}\&times;A^H\&CenterDot;\hat{r};$

Wherein, A represents sytem matrix, The I/Q road signal of expression input, σ ²The expression noise variance, The demodulation symbol that the expression joint-detection obtains, I represents diagonal matrix.

This symbol judgement device carries out symbol judgement to the demodulation symbol of maximal ratio combiner output, obtains sending the estimated value of symbol:

$D=({\hat{d}}^1,{\hat{d}}^2,...,{\hat{d}}^N);$

${\hat{d}}^n=(d_1^n,d_2^n,...,d_K^n);$

Wherein

The court verdict of representing n the pairing demodulation symbol of activated code channel.

Described symbol judgement device is a demodulation symbol hard decision device, and the hard decision result who adopts this demodulation symbol hard decision device to obtain is:

$d_k^n=\mathrm{sign}\left(y_k^n\right)=\left\{\begin{array}{cc}1& y_k^n\&GreaterEqual;0\\ -1& y_k^n<0\end{array}\right.;$

Described symbol judgement device is a demodulation symbol soft-decision device, and the soft-decision result who adopts this demodulation symbol soft-decision device to obtain is:

$d_k^n=\tanh \left(\frac{m\&CenterDot;y_k^n}{{\mathrm{\&sigma;}}^2}\right);$

Wherein, m represents the average of received signal amplitude, σ ²The noise variance of expression received signal, tanh represents hyperbolic tangent function.

Described cell signal reconfiguration device comprises modulation frequency multiplier, a N acoustic convolver and the activated code channel signal superimposer that connects successively;

Scrambler ScC, the spread spectrum codes C hC=(C on the activated code channel that this modulation frequency multiplier adopts according to current area ₁, C ₂..., C _N),

Court verdict to the output of symbol judgement device is modulated and spread spectrum, obtains the estimated value that transmits of chip-level on each activated code channel:

$V=({\hat{v}}^1,{\hat{v}}^2,...,{\hat{v}}^N);$

${\hat{v}}^n=(v_1^n,v_2^n,...,v_{K\&times;\mathrm{SF}}^n);$

Wherein

The estimated value that transmits of representing n the chip-level on the activated code channel;

This N acoustic convolver input be connecting channel impulse response device also, it obtains the reconstruction signal on each activated code channel to finishing convolution operation by chip sequence on each activated code channel of modulation frequency multiplier output and the channel impulse response that is generated by the channel impulse response device:

$W=({\hat{w}}^1,{\hat{w}}^2,...,{\hat{w}}^N);$

${\hat{w}}^n=(w_1^n,w_2^n,...,w_{K\&times;\mathrm{SF}}^n);$

${\hat{w}}^n=H\&CircleTimes;{\hat{v}}^n;$

Wherein, Represent n the reconstruction signal on the code channel, The estimated value that transmits of representing n the chip-level on the activated code channel;

This activated code channel signal superimposer superposes to the reconstruction signal on each activated code channel, finishes the activated code channel merging, thereby finishes the reconstruct of cell signal, obtains the reconstruction signal of sub-district

${\hat{x}}^s=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\hat{w}}^n$

Represent n the reconstruction signal on the code channel.

Further, described cell signal reconfiguration device also comprises a weighting multiplier, and its input connects the output of activated code channel signal superimposer, and this weighting multiplier is to the sub-district reconstruction signal of activated code channel signal superimposer output

Multiply by specific weighted factor ρ ^s, reduce because the incorrect performance loss that causes of symbol judgement:

${\hat{x}}^s={\hat{x}}^s\&times;{\mathrm{\&rho;}}^s.$

The SIC progression S that this device is provided with in advance according to system, and the residual signal after disturbing is removed in each sub-district of calculating of a last SIC level

To each SIC level, repeat and eliminate the operation that common-frequency cell signal disturbs, until the SIC operation of finishing all grades.

A kind of method and apparatus of eliminating the common-frequency cell signal interference based on counteracting serial interference provided by the invention, can be with less implementation complexity, to a great extent, particularly co-frequency neighbor cell power is higher than under the mal-condition of this sub-district, eliminate the influence of common-frequency cell signal, improve the receptivity of this cell signal.

Description of drawings

The TD-SCDMA system frame structure schematic diagram that Fig. 1 provides for 3GPP standard in the background technology;

Fig. 2 is the structural representation that employing counteracting serial interference method provided by the invention is eliminated co-channel interference;

Fig. 3 is the structural representation of the CEIGU based on the joint-detection demodulation result provided by the invention.

Embodiment

Below in conjunction with Fig. 2～Fig. 3, the specific embodiment by optimizing is described in detail the present invention.

Serial interference elimination with a time slot of TD-SCDMA is an example, supposes that the received signal of this time slot is

Wherein, r ₁～r ₃₅₂The received signal of expression data segment DATA1, r ₁₁₃ ^BM, r ₁₁₄ ^BM..., r ₁₂₈ ^BM, r ₁ ^BM... r ₁₂₈ ^BMThe middle guiding code sequence signal that expression receives, r ₃₅₃～r ₇₀₄The received signal of expression data segment DATA2.

As shown in Figure 3, be the structural representation of the CEIGU based on the joint-detection demodulation result provided by the invention, concrete operating procedure is as follows:

Step 1, active path separate:

Step 1.1, at each sub-district, by matched filter 410_1, the basic middle guiding code sequence with this sub-district pursues bit circulation xor operation, rated output DP respectively with back 128 chip data of the middle guiding code sequence in input signal part;

If the basic middle guiding code sequence of current area is BM=(m ₁, m ₂..., m ₁₂₈), the data of back 128 chips of the middle guiding code sequence part in the input signal of reception are

Then the computing formula of the power DP on each path is:

${\mathrm{DP}}_k=\underset{n=1}{\overset{128}{\mathrm{\&Sigma;}}}\left|\right|r_n^{\mathrm{BM}}*m_{(n-k+1)\mathrm{mod}128}\left|\right|;$

Step 1.2, active path detector 490 detection active paths by being connected with matched filter 410_2:

Power DP on each path and certain threshold Th are compared; Selection is an active path more than or equal to the pairing path of power DP of thresholding Th, otherwise is invalid path; The final detected L bar of active path detector active path is: P _Eff=(p ₁, p ₂..., p _L);

Step 2, generation channel impulse response:

The ChE that step 2.1, the matched filter 410_2 that passes through connection successively and channel estimator 480 calculate on each paths:

If the basic middle guiding code sequence of current area is BM=(m ₁, m ₂..., m ₁₂₈), the data of back 128 chips of the middle guiding code sequence part in the input signal of reception are

Then the channel estimating ChE on each path is:

${\mathrm{ChE}}_k=\underset{n=1}{\overset{128}{\mathrm{\&Sigma;}}}{r}_n^{\mathrm{BM}}*m_{(n-k+1)\mathrm{mod}128};$

Step 2.2, generate channel impulse responses by channel impulse response device 470:

Channel impulse response device 470 connects the output of effective path detector 490 and channel estimator 480 respectively, according to the active path and the channel estimating of output respectively, generates channel impulse response H=(h ₁, h ₂..., h _T), its length T is represented the maximum delay that system supports, and the locational value of this channel impulse response active path is the channel estimation value on this path, and the locational value of non-active path is zero, that is:

$h_i=\left\{\begin{array}{cc}{\mathrm{ChE}}_i& {\mathrm{DP}}_i\&GreaterEqual;\mathrm{Th}\\ 0& {\mathrm{DP}}_i<\mathrm{Th}\end{array}\right.;$

Step 3, produce demodulation symbol based on matched filter;

Step 3.1, the data division in the input signal is carried out descrambling, de-spreading operation by matched filter 410_3:

The input of this matched filter 410_3 also connects effective path detector 490, according to position P, the scrambler ScC of current area of the active path of its output and the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, and matched filter 410_3 is to the data division in the input signal

Carry out descrambling, de-spreading operation, the symbol that obtains after descrambling, the despreading is:

$U=({\hat{u}}^1,{\hat{u}}^2,...,{\hat{u}}^N);$

${\hat{u}}^n=({\hat{u}}_1^n,{\hat{u}}_2^n,...,{\hat{u}}_L^n);$

${\hat{u}}_l^n=(u_{(l,1)}^n,u_{(l,2)}^n,...,u_{(l,K)}^n);$

$u_{(l,k)}^n=\underset{i=1}{\overset{\mathrm{SF}}{\mathrm{\&Sigma;}}}{r}_{p_k+(k-1)\&CenterDot;\mathrm{SF}+i}\&times;\mathrm{conj}\left(c_i^n\right)\&times;\mathrm{conj}\left({\mathrm{ScC}}_i\right);$

Wherein, Represent n the pairing symbol of activated code channel, Represent n the symbol on the activated code channel l bar active path, K represents the number of symbol;

Step 3.2, carry out high specific by the symbol that obtains after 420 pairs of descramblings of maximal ratio combiner, the despreading and merge, obtain demodulation symbol:

The input of this maximal ratio combiner 420 connects matched filter 410_3 and channel impulse response device 470 respectively, according to channel impulse response, it is the channel estimating on the active path, descrambling, the symbol after the despreading on 420 pairs of different paths of maximal ratio combiner carry out the high specific union operation, obtain the demodulation symbol on each activated code channel:

$Y=({\hat{y}}^1,{\hat{y}}^2,...,{\hat{y}}^N);$

${\hat{y}}^n=(y_1^n,y_2^n,...,y_K^n);$

$y_k^n=\underset{l=1}{\overset{L}{\mathrm{\&Sigma;}}}\mathrm{conj}\left({\mathrm{ChE}}_l\right)\&times;u_{(l,k)}^n;$

Wherein,

Represent n the pairing demodulation symbol of activated code channel,

The symbol of representing n activated code channel of the 1st k symbol of active path;

Step 3.3, joint-detection:

Dot product result and the channel impulse response of the scrambler that step 3.3.1, sytem matrix maker 590 adopt according to current area, the spreading code of activation carry out convolution, the generation sytem matrix:

The input of this sytem matrix maker 590 connects scrambling code generator and spreading code maker 580 and channel impulse response device 470 respectively, according to the scrambler ScC of the current area that is generated by scrambling code generator and spreading code maker 580, the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, and by the channel impulse response H that channel impulse response device 470 generates, calculates sytem matrix A:

$b^n=H\&CircleTimes;(\mathrm{ScC}.*C_n);$

B＝[b ¹，b ²，…，b ^N] ^T；

Wherein, [] ^TThe representing matrix transposition, the number of the B matrix in the A matrix need to equal the symbol numbers of joint-detection;

Step 3.3.2, combined detector 530 adopt ZF linear block balance device algorithm or minimum Mean Square Error Linear block equalizers algorithm to carry out the joint-detection operation, obtain demodulation symbol;

The input of this combined detector 530 is connected system matrix maker 590 and maximal ratio combiner 420 respectively;

Combined detector 530 adopts described ZF linear block balance device algorithm, and the demodulation symbol that obtains is:

$\hat{d}={(A^H\&CenterDot;A)}^{-1}\&times;A^H\&CenterDot;\hat{r};$

Wherein, A represents sytem matrix, The I/Q road signal of expression input,

The demodulation symbol that the expression joint-detection obtains.

Combined detector 530 adopts described minimum Mean Square Error Linear block equalizers algorithm, and the demodulation symbol that obtains is:

$\hat{d}={(A^H\&CenterDot;A+{\mathrm{\&sigma;}}^2\&CenterDot;I)}^{-1}\&times;A^H\&CenterDot;\hat{r};$

Wherein, A represents sytem matrix, The I/Q road signal of expression input, σ ²The expression noise variance, The demodulation symbol that the expression joint-detection obtains, I represents diagonal matrix.

430 pairs of demodulation symbols that produced by combined detector 530 of step 3.4, symbol judgement device carry out symbol judgement, and the estimated value that obtains sending symbol is:

$D=({\hat{d}}^1,{\hat{d}}^2,...,{\hat{d}}^N);$

${\hat{d}}^n=(d_1^n,d_2^n,...,d_K^n);$

Wherein

The court verdict of representing n the pairing demodulation symbol of activated code channel.

In the step 3.4, described symbol judgement comprises hard decision and soft-decision, and described symbol judgement device 430 can be a demodulation symbol hard decision device, also can be demodulation symbol soft-decision device;

Described hard decision is operated by demodulation symbol hard decision device, and the result who obtains behind the hard decision is:

$d_k^n=\mathrm{sign}\left(y_k^n\right)=\left\{\begin{array}{cc}1& y_k^n\&GreaterEqual;0\\ -1& y_k^n<0\end{array}\right.;$

Described soft-decision is operated by demodulation symbol soft-decision device, and the result who obtains behind the soft-decision is:

$d_k^n=\tanh \left(\frac{m\&CenterDot;y_k^n}{{\mathrm{\&sigma;}}^2}\right);$

Wherein, m represents the average of received signal amplitude, σ ²The noise variance of expression received signal, tanh represents hyperbolic tangent function.

Step 4, reconstruct cell signal:

Step 4.1, modulate the spread spectrum operation, obtain the chip sequence on the activated code channel by the result of modulation frequency multiplier 440 pairs of symbol judgements:

The input bound symbol decision device 430 of this modulation frequency multiplier 440, scrambler ScC, the spread spectrum codes C hC=(C on the activated code channel that it adopts according to current area ₁, C ₂..., C _N),

Court verdict to 430 outputs of symbol judgement device is modulated and spread spectrum, obtains the estimated value that transmits of chip-level on each activated code channel:

$V=({\hat{v}}^1,{\hat{v}}^2,...,{\hat{v}}^N);$

${\hat{v}}^n=(v_1^n,v_2^n,...,v_{K\&times;\mathrm{SF}}^n);$

Wherein

The estimated value that transmits of representing n the chip-level on the activated code channel;

Step 4.2, finish the reconstruct of acknowledge(ment) signal on some activated code channels by N acoustic convolver 460 correspondences:

The input of this N acoustic convolver 460 connects modulation frequency multiplier 440 and channel impulse response device 470 respectively, and chip sequence and channel impulse response on each activated code channel of output are finished convolution operation, obtains the reconstruction signal on each activated code channel:

$W=({\hat{w}}^1,{\hat{w}}^2,...,{\hat{w}}^N);$

${\hat{w}}^n=(w_1^n,w_2^n,...,w_{K\&times;\mathrm{SF}}^n);$

${\hat{w}}^n=H\&CircleTimes;{\hat{v}}^n;$

Wherein,

Represent n the reconstruction signal on the code channel,

The estimated value that transmits of representing n the chip-level on the activated code channel;

Step 4.3, the reconstruction signal on each activated code channel is superposeed, finish activated code channel and merge, thereby finish the reconstruct of cell signal, obtain the reconstruction signal of sub-district by the activated code channel signal superimposer that is connected with N acoustic convolver 460 450

${\hat{x}}^s=\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{\hat{w}}^n;$

Step 4.4, the weighting multiplier that links to each other with the output of activated code channel signal superimposer 450 are to sub-district reconstruction signal weighting: with this sub-district reconstruction signal

Multiply by specific weighted factor ρ ^s, reduce because the incorrect performance loss that causes of symbol judgement:

${\hat{x}}^s={\hat{x}}^s\&times;{\mathrm{\&rho;}}^s.$

As shown in Figure 2, eliminate the structural representation of co-channel interference for adopting the counteracting serial interference method, its core concept is the signal of each co-frequency cell of serial reconstruct, and finishes interference signal on this basis and eliminate, and concrete steps are as follows:

For current this sub-district, establish and have M co-frequency neighbor cell; Current reception data I/Q road sampling is input as

Wherein, N is the length of sample sequence; The progression of the counteracting serial interference of default is S;

Step 1, to each sub-district, sub-district received signal recovery unit 320 is with the reconstruction signal of this sub-district in the s-1 level interference cancellation process

With the residual signal after all cell interfering signal before the removal in the s level interference cancellation process

Stack recovers the received signal of this sub-district

${\hat{e}}_j^s={\hat{r}}_{j-1}^s+{\hat{x}}_j^{s-1};$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1;

In the described step 1, this sub-district received signal recovery unit 320 of each cell reuse;

In the described step 1, if carry out first order interference eliminated, promptly during s=1, the reconstruction signal of this sub-district is 0; If first carries out the sub-district of interference eliminated, promptly during j=1, the residual signal before removing in the then described interference cancellation process after all cell interfering signal is 0;

Step 2, according to the processing method of as described in Figure 3 the demodulation symbol reconstruct cell signal that produces based on JD, based on the CEIGU 500 of JD received signal according to each sub-district of the s level that obtains in the step 1

The reconstruct of each sub-district received signal is finished in corresponding serial, obtains the reconstruction signal of each sub-district of s level:

${\hat{x}}_j^s=(x_{(j,1)}^s,x_{(j,2)}^s,...,x_{(j,N)}^s);$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1;

In the described step 2, this CEIGU of each cell reuse finishes interference signal reconstruct;

Step 3, to each sub-district, the sub-district reconstruction signal is removed unit 330 reconstruction signal of this sub-district in the interference cancellation process at the corresponding levels is removed from input signal, obtains removing the residual signal after this area interference; Be that the sub-district reconstruction signal is removed the reconstruction signal of unit 330 with this sub-district in the s level interference cancellation process

From input signal

In remove, obtain the residual signal after this area interference of removal of s level

${\hat{r}}_j^s={\hat{e}}_j^s-{\hat{x}}_j^s;$

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1;

In the described step 3, this sub-district reconstruction signal of each cell reuse is removed unit 330.

Step 4, according to the SIC progression S that system is provided with in advance, repeated execution of steps 1～3 is up to the SIC operation of finishing all grades.

In this method, when respectively each co-frequency neighbor cell being carried out signal reconstruction, the basic cell information of required current co-frequency neighbor cell comprises basic middle guiding code sequence, and the spreading code of scrambler and activation etc. is that system is known, or obtain by detection.

The obviously clear and understanding of those of ordinary skill in the art, the most preferred embodiment that the present invention lifted only in order to explanation the present invention, and is not limited to the present invention, the present invention for the technical characterictic among each embodiment, can combination in any, and do not break away from thought of the present invention.According to a kind of method and apparatus of eliminating the common-frequency cell signal interference based on counteracting serial interference disclosed by the invention, can there be many modes to revise disclosed invention, and except the above-mentioned optimal way that specifically provides, the present invention can also have other many embodiment.Therefore, all genus are conceived getable method of institute or improvement according to the present invention, all should be included within the interest field of the present invention.Interest field of the present invention is defined by the appended claims.

Claims (28)

1. eliminate the method that common-frequency cell signal disturbs based on counteracting serial interference for one kind, it is characterized in that, this sub-district and each co-frequency neighbor cell adopt the method for each cell signal of demodulation symbol reconstruct that produces based on joint-detection respectively separately, and interference eliminated is carried out in serial, comprises following steps:

Step 1, to each sub-district, promptly current this sub-district and M co-frequency neighbor cell, sub-district received signal recovery unit (320) is with the reconstruction signal of this sub-district in the s-1 level interference cancellation process With the residual signal after all cell interfering signal before the removal in the s level interference cancellation process Stack recovers the received signal of each sub-district

Wherein, s=1,2 ..., S, and S represents the progression of the counteracting serial interference of default; J=1,2 ..., M, M+1;

Step 2, according to the sampling on current reception data I/Q road input

With the signal sum after the s-1 level interference eliminated, channel estimating and interference reconstruction unit (500) adopt the method for each cell signal of demodulation symbol reconstruct that produces based on joint-detection, the reconstruct of each sub-district received signal is finished in serial successively, obtains the reconstruction signal of each sub-district of s level:

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1, Z are the length of sample sequence;

This step 2 specifically comprises:

Step 2.1, active path separate;

Described step 2.1 comprises following substep:

Step 2.1.1, at each sub-district, with back 128 chip data of the middle guiding code sequence in input signal part By matched filter (410_1), respectively with the basic middle guiding code sequence BM=(m of this sub-district ₁, m ₂..., m ₁₂₈) pursue bit circulation xor operation, calculate the each power DP on each path by bit XOR result:

Step 2.1.2, detect active path by active path detector (490):

Power DP on each path and certain threshold Th are compared; Selection is an active path more than or equal to the pairing path of power DP of thresholding Th, otherwise is Invalid path; The final detected L bar of active path detector (490) active path is: P _Eff=(p ₁, p ₂..., p _L); Step 2.2, generation channel impulse response;

Described step 2.2 comprises following substep:

Step 2.2.1, calculate channel estimating ChE on each path by matched filter (410_2) and channel estimator (480):

Basic middle guiding code sequence according to current area is BM=(m ₁, m ₂..., m ₁₂₈), and the data of back 128 chips of the part of the middle guiding code sequence in the input signal that receives are The channel estimating ChE that calculates on each path is:

Step 2.2.2, according to the channel estimating that obtains among active path that obtains among the step 2.1.2 and the step 2.2.1, generate channel impulse response H=(h by channel impulse response device (470) ₁, h ₂..., h _T), its length T is represented the maximum delay that system supports, and the locational value of this channel impulse response active path is the channel estimation value on this path, and the locational value of non-active path is zero, that is:

Step 2.3, produce demodulation symbol based on joint-detection;

Described step 2.3 specifically comprises:

Step 2.3.1, the data division in the input signal is carried out descrambling, de-spreading operation by matched filter (410_3):

According to the position P of active path, the scrambler ScC of current area and the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, adopts matched filter (410_3) to the data division in the input signal

Carry out descrambling, de-spreading operation, the symbol that obtains after descrambling, the despreading is:

Wherein, Represent n the pairing symbol of activated code channel,

Represent n the symbol on the activated code channel l bar active path, K represents the number of symbol, u _{(l, k)} ⁿThe symbol of representing n activated code channel of k symbol of l active path;

Step 2.3.2, the symbol that is obtained after to descrambling, despreading by maximal ratio combiner (420) carry out high specific and merge, and obtain demodulation symbol:

According to channel impulse response, i.e. channel estimating on the active path, maximal ratio combiner (420) carries out the high specific union operation to the descrambling on the different paths, symbol after the despreading, obtains the demodulation symbol on each activated code channel:

Wherein,

Represent n the pairing demodulation symbol of activated code channel, u _{(l, k)} ⁿThe symbol of representing n activated code channel of k symbol of l active path;

Step 2.3.3, joint-detection;

Step 2.3.4, demodulation symbol is carried out symbol judgement, obtains sending the estimated value of symbol by symbol judgement device (430):

Wherein,

The court verdict of representing n the pairing demodulation symbol of activated code channel;

Step 2.4, reconstruct cell signal;

Described step 2.4 comprises following substep:

Step 2.4.1, the result of symbol judgement is modulated the spread spectrum operation, obtains the chip sequence on the activated code channel by modulation frequency multiplier (440):

Scrambler ScC, the spread spectrum codes C hC=(C on the activated code channel according to the current area employing ₁, C ₂..., C _N),

Result to symbol judgement modulates and spread spectrum by modulation frequency multiplier (440), obtains the estimated value that transmits of chip-level on each activated code channel:

Wherein The estimated value that transmits of representing n the chip-level on the activated code channel;

Step 2.4.2, finish the reconstruct of acknowledge(ment) signal on some activated code channels by acoustic convolver (460) correspondence:

By acoustic convolver (460) channel impulse response that obtains in chip sequence on each activated code channel that obtains among the step 2.4.1 and the step 2.2 is finished convolution operation, obtains the reconstruction signal on each activated code channel:

Wherein,

Represent n the reconstruction signal on the code channel,

The estimated value that transmits of representing n the chip-level on the activated code channel;

Step 2.4.3, the reconstruction signal on each activated code channel is superposeed, finish activated code channel and merge, thereby finish the reconstruct of cell signal, obtain the reconstruction signal of sub-district by activated code channel signal superimposer (450)

Represent n the reconstruction signal on the code channel;

Step 3, to each sub-district, the sub-district reconstruction signal is removed unit (330) successively with the reconstruction signal of this sub-district in the s level interference cancellation process From input signal In remove, obtain the residual signal after this area interference of removal of s level

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1;

Step 4, according to the counteracting serial interference progression that system is provided with in advance, repeated execution of steps 1～3 is up to the counteracting serial interference operation of finishing all grades.

2. the method for disturbing based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 1 is characterized in that in the step 1, when s=1, promptly carry out first order interference eliminated, the reconstruction signal of this sub-district is 0.

3. the method for eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 1, it is characterized in that, in the step 1, when j=1, promptly carry out the interference eliminated of first sub-district, the residual signal before removing in the then described interference cancellation process after all cell interfering signal is 0.

4. the method for disturbing based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 1 is characterized in that described step 2.3.3 comprises following substep:

Dot product result and the channel impulse response of the scrambler that step 2.3.3.1, sytem matrix maker (590) adopt according to current area, the spreading code of activation carry out convolution, the generation sytem matrix:

According to the scrambler ScC of the current area that generates by scrambling code generator and spreading code maker (580), the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, and by the channel impulse response H that obtains among the step 2.2.2, calculates sytem matrix A by sytem matrix maker (590):

B＝[b ¹，b ²，…，b ^N] ^T；

Wherein, [] ^TThe representing matrix transposition, the number of the B matrix in the A matrix need to equal the symbol numbers of joint-detection;

Step 2.3.3.2, combined detector (530) adopt ZF linear block balance device algorithm or minimum Mean Square Error Linear block equalizers algorithm to carry out the joint-detection operation, obtain demodulation symbol

5. the method for disturbing based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 4 is characterized in that, among the step 2.3.3.2, adopts described ZF linear block balance device algorithm, the demodulation symbol that obtains

For:

Wherein, A represents sytem matrix,

The I/Q road signal of expression input,

The demodulation symbol that the expression joint-detection obtains.

6. the method for disturbing based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 4 is characterized in that, among the step 2.3.3.2, adopts described minimum Mean Square Error Linear block equalizers algorithm, the demodulation symbol that obtains

For:

Wherein, A represents sytem matrix, The I/Q road signal of expression input, σ ²The expression noise variance,

The demodulation symbol that the expression joint-detection obtains, I represents diagonal matrix.

7. the method for eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 1, it is characterized in that among the step 2.3.4, described symbol judgement is a hard decision, by demodulation symbol hard decision device demodulation symbol is carried out symbol judgement, the hard decision result who obtains is:

8. the method for eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 1, it is characterized in that among the step 2.3.4, described symbol judgement is a soft-decision, by demodulation symbol soft-decision device demodulation symbol is carried out symbol judgement, the soft-decision result who obtains is:

Wherein, m represents the average of received signal amplitude, σ ²The noise variance of expression received signal, tanh represents hyperbolic tangent function.

9. the method for disturbing based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 1 is characterized in that described step 2.4 also comprises step 2.4.4, to the sub-district reconstruction signal

Multiply by specific weighted factor ρ ^s, be weighted operation:

10. eliminate the device that common-frequency cell signal disturbs based on counteracting serial interference for one kind, it is characterized in that, comprise successively the sub-district received signal recovery unit (320) that connects, remove unit (330) based on the channel estimating of joint-detection and interference reconstruction unit (500) and sub-district reconstruction signal;

Described sub-district received signal recovery unit (320) is successively for current this sub-district and M co-frequency neighbor cell, with the reconstruction signal of this sub-district in the s-1 level interference cancellation process

With the residual signal after all cell interfering signal before the removal in the s level interference cancellation process

Stack recovers the received signal of each sub-district successively

Wherein, s=1,2 ..., S, and S represents the progression of the counteracting serial interference of default; J=1,2 ..., M, M+1;

Described channel estimating and interference reconstruction unit (500) based on joint-detection are according to the sampling input on current reception data I/Q road With the signal sum after the s-1 level interference eliminated, adopt the processing method of the demodulation symbol reconstruct cell signal that produces based on joint-detection, the reconstruct of each sub-district received signal is finished in serial successively, obtains the reconstruction signal of each sub-district of s level:

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1, Z are the length of sample sequence;

Described channel estimating and interference reconstruction unit (500) based on joint-detection comprise the active path separator that connects by circuit, channel impulse response device, based on the demodulation symbol generating apparatus and the cell signal reconfiguration device of joint-detection;

Described active path separator comprises first matched filter (410_1) and the active path detector (490) that connects successively;

Back 128 chip data BM=(m of the middle guiding code sequence in the input receiving inputted signal of described first matched filter (410_1) ₁, m ₂..., m ₁₂₈), with the basic middle guiding code sequence of current area Pursue bit circulation xor operation, calculate each power DP by bit XOR result:

Described active path detector (490) compares the power DP value on each path of first matched filter (410_1) output respectively with certain threshold Th; Selection is an active path more than or equal to the pairing path of power DP of thresholding Th, otherwise is Invalid path; The final detected L bar of active path detector (490) active path is: P _Eff=(p ₁, p ₂..., p _L);

Described channel impulse response device comprises second matched filter (410_2), channel estimator (480) and the channel impulse response device (470) that connects successively;

Back 128 chip data BM=(m of the middle guiding code sequence in the input receiving inputted signal of described second matched filter (410_2) ₁, m ₂..., m ₁₂₈), in conjunction with the basic middle guiding code sequence of current area

The channel estimating ChE that calculates on each path by channel estimator (480) is:

The input of described channel impulse response device (470) also connects the output of effective path detector (490); This channel impulse response device (470) generates channel impulse response H=(h according to active path and channel estimating ₁, h ₂..., h _T):

Wherein, the length T of channel impulse response is represented the maximum delay that system supports;

Described demodulation symbol generating apparatus based on joint-detection comprises the 3rd matched filter (410_3), maximal ratio combiner (420), joint-detection device and the symbol judgement device (430) that connects successively;

Described cell signal reconfiguration device comprises modulation frequency multiplier (440), acoustic convolver (460) and the activated code channel signal superimposer (450) that connects successively;

Described sub-district reconstruction signal is removed unit (330) to each sub-district, successively with the reconstruction signal of this sub-district in the s level interference cancellation process

From input signal In remove, obtain the residual signal after this area interference of removal of s level

Wherein, s=1,2 ..., S, j=1,2 ..., M, M+1.

11. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 10 is characterized in that when s=1, promptly carry out first order interference eliminated, the reconstruction signal of this sub-district is 0.

12. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 10, it is characterized in that, when j=1, promptly carry out the interference eliminated of first sub-district, the residual signal before removing in the described interference cancellation process after all cell interfering signal is 0.

13. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 14, it is characterized in that, data division in the input receiving inputted signal of described the 3rd matched filter (410_3), and be connected with active path detector (490);

The 3rd matched filter (410_3) is according to the position P of active path, the scrambler ScC of current area and the spread spectrum codes C hC=(C of activation ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor, to the data division in the input signal Carry out descrambling, de-spreading operation, the symbol that obtains after descrambling, the despreading is:

Wherein, Represent n the pairing symbol of activated code channel, Represent n the symbol on the activated code channel l bar active path, K represents the number of symbol, u _{(l, k)} ⁿThe symbol of representing n activated code channel of k symbol of l active path.

14. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 14, it is characterized in that, the input of described maximal ratio combiner (420) is connecting channel impulse response device (470) also, it is according to channel impulse response, it is the channel estimating on the active path, descrambling on the different paths of the 3rd matched filter (410_3) output, the symbol after the despreading are carried out the high specific union operation, obtain the demodulation symbol on each activated code channel:

Wherein,

Represent n the pairing demodulation symbol of activated code channel, u _{(l, k)} ⁿThe symbol of representing n activated code channel of the 1st k symbol of active path.

15. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 14, it is characterized in that described joint-detection device comprises scrambling code generator and spreading code maker (580), sytem matrix maker (590) and the combined detector (530) that connects successively.

16. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 15 is characterized in that the scrambler ScC of the current area that described scrambling code generator and spreading code maker (580) generate, and the spread spectrum codes C hC=(C that activates ₁, C ₂..., C _N),

Wherein N represents the number of activated code channel, and SF represents spreading factor.

17. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 15, it is characterized in that, the input of described sytem matrix maker (590) is the output of connecting channel impulse response device (470) also, it is according to scrambler ScC, the spread spectrum codes C hC of activation of the current area that is generated by scrambling code generator and spreading code maker (580), and, calculate sytem matrix A by the channel impulse response H that channel impulse response device (470) generates:

B＝[b ¹，b ²，…，b ^N] ^T；

Wherein, [] ^TThe representing matrix transposition, the number of the B matrix in the A matrix need to equal the symbol numbers of joint-detection.

18. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 15 is characterized in that the input of described combined detector (530) is connected system matrix maker (590) and maximal ratio combiner (420) respectively; Adopt ZF linear block balance device algorithm or minimum Mean Square Error Linear block equalizers algorithm to carry out the joint-detection operation, obtain demodulation symbol

19. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 18 is characterized in that described combined detector (530) adopts ZF linear block balance device algorithm, detects the demodulation symbol that obtains and is:

Wherein, A represents sytem matrix, The I/Q road signal of expression input,

The demodulation symbol that the expression joint-detection obtains.

20. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 18 is characterized in that described combined detector (530) adopts minimum Mean Square Error Linear block equalizers algorithm, detects the demodulation symbol that obtains and is:

Wherein, A represents sytem matrix, The I/Q road signal of expression input, σ ²The expression noise variance,

The demodulation symbol that the expression joint-detection obtains, I represents diagonal matrix.

21. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 14, it is characterized in that, described symbol judgement device (430) carries out symbol judgement to the demodulation symbol of maximal ratio combiner (420) output, obtains sending the estimated value of symbol:

Wherein

The court verdict of representing n the pairing demodulation symbol of activated code channel.

22. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 21 is characterized in that described symbol judgement device (430) is a demodulation symbol hard decision device, the hard decision result who adopts this demodulation symbol hard decision device to obtain is:

23. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 21 is characterized in that described symbol judgement device (430) is a demodulation symbol soft-decision device, the soft-decision result who adopts this demodulation symbol soft-decision device to obtain is:

Wherein, m represents the average of received signal amplitude, σ ²The noise variance of expression received signal, tanh represents hyperbolic tangent function.

24. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 14 is characterized in that scrambler ScC, the spread spectrum codes C hC=(C on the activated code channel that described modulation frequency multiplier (440) adopts according to current area ₁, C ₂..., C _N), Court verdict to symbol judgement device (430) output is modulated and spread spectrum, obtains the estimated value that transmits of chip-level on each activated code channel:

Wherein The estimated value that transmits of representing n the chip-level on the activated code channel.

25. the device that disturbs based on counteracting serial interference elimination common-frequency cell signal as claimed in claim 14 is characterized in that the number of described acoustic convolver (460) is N, a corresponding N activated code channel; The input of this N acoustic convolver (460) is gone back connecting channel impulse response device (470) respectively;

A described N acoustic convolver (460) obtains the reconstruction signal on each activated code channel to finishing convolution operation by chip sequence on each activated code channel of modulation frequency multiplier (440) output and the channel impulse response that is generated by channel impulse response device (470):

Wherein, Represent n the reconstruction signal on the code channel,

The estimated value that transmits of representing n the chip-level on the activated code channel.

26. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 14, it is characterized in that, described activated code channel signal superimposer (450) superposes to the reconstruction signal on each activated code channel, finishing activated code channel merges, with the reconstruct of cell signal, obtain the reconstruction signal of sub-district

Represent n the reconstruction signal on the code channel.

27. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 14, it is characterized in that, described cell signal reconfiguration device also comprises a weighting multiplier, and its input connects the output of activated code channel signal superimposer (450);

This weighting multiplier is to the sub-district reconstruction signal of activated code channel signal superimposer (450) output

Multiply by specific weighted factor ρ ^s:

28. the device of eliminating the common-frequency cell signal interference based on counteracting serial interference as claimed in claim 10, it is characterized in that, the counteracting serial interference progression S that is provided with according to system, and the residual signal after disturbing is removed in each sub-district of calculating of a last serial Interference Cancellation level

To each counteracting serial interference level, repeat and eliminate the operation that common-frequency cell signal disturbs, until the counteracting serial interference operation of finishing all grades.