CN101494467A - Multiuser serial interference delete receiver and method with improved constringency performance - Google Patents

Abstract

The invention discloses a multi-user serial interference deletion receiver with improved convergence performance and a method thereof. In the receiver, an interference deletion unit adds reconstructing signals corresponding to users in a former iterated order with residual signals which are connected with all the front interference deletion units in series and are obtained after the interference is eliminated from receiving signals; added data signals are detected and the detected data is used for generating an estimation value of the user data; and the reconstructed signals generated by the estimation value of the user data are subtracted from the added data signals so as to obtain the residual signals which are then transmitted to a latter interference deletion unit. In addition, stepped iteration is carried out to the reconstructing signals generated by the estimation value of the user data, and the estimation value of the user data obtained by the last step iteration is input into a judging unit for judgment so as to obtain a restoring signal of the user. The interference deletion unit comprises a nonlinear processing module, and the estimation value of the user data is determined according to the credibility of the user data detected currently so as to lead the receiver to be converged fast.

Description

Multiuser serial interference delete receiver and method with improved constringency performance

Technical field

The present invention relates to the signal reception technique in CDMA (code division multiple access) communication system, relate in particular to a kind of multiuser serial interference delete receiver and method with improved constringency performance.

Background technology

Cdma system is an interference-limited system, and multiple access disturbs all the time and exists, therefore need seek suitable receiver technology and eliminate interference, and be the effective way that anti-multipath decline, elimination are disturbed and handle based on the time domain that Rake (RAKE) receives.In the CDMA spread spectrum system, channel width is far longer than the flat fading bandwidth of channel.Being different from traditional modulation technique need eliminate intersymbol interference between adjacent-symbol with equalization algorithm, and the CDMA spreading code just requires it that good autocorrelation performance is arranged when selecting.Like this, the time delay expansion that occurs in the wireless channel can be regarded as just by the transmission once more of the number of delivering a letter.Owing to contain utilizable information in multipath signal, cdma receiver can be by merging the signal to noise ratio that multipath signal improves received signal.What RAKE receiver was done is exactly: by each the road signal in a plurality of correlation detector receiving multipath signals, and they are combined, the multipath structure that therefore can make full use of signal in time domain improves the output signal-to-noise ratio of system, thereby becomes the anti-multipath decline technology that extensively is employed in the present cdma system.

Serial interference delete receiver is to estimate multiple access earlier to insert interference between interference and footpath, deletes the interference that estimates then in order successively.Multistage serial interference delete device is exactly to disturb to be estimated successively and delete in multistage.

And the grouping serial interference delete is exactly on the basis of serial interference delete, and the user is divided into groups according to the quality of condition of acceptance, and the group that condition of acceptance is good at first detects.Carry out the parallel interference deletion in the group, carry out serial interference delete between group, compare serial interference delete like this, can reduce system's time delay.

To utilizing RAKE receiver to carry out our discovery in the research of (grouping) serial interference delete, how to recover rightly to disturb, make it to approach original interference signal, be the key of decision (grouping) serial interference delete receiver performance.Owing in the multi-user system, all be to disturb for other users of some users, recovering so rightly to disturb is exactly will be in the iterative process of interference delete, each user's of reconstruct the information exactly of trying one's best.In traditional multi-user interference delete procedure, to directly carry out hard decision to user's data, obviously such processing is not quite reasonable, particularly less or disturbing the bigger iteration initial stage in signal to noise ratio, the diffusion phenomena that direct hard decision can make the mistake finally make whole interference delete iterative algorithm not restrain.

Summary of the invention

In view of above situation, the technical problem to be solved in the present invention is exactly to propose a kind of multiuser serial interference delete receiver and method with improved constringency performance, makes that the user's reconstruct data in the iterative process is more reasonable, thereby has quickened the convergence of receiver.

In order to address the above problem, the invention provides a kind of multiuser serial interference delete receiver with improved constringency performance, the decision unit that the interference delete unit that comprises the polyphone with at least one iteration stages links to each other with output with afterbody polyphone interference delete unit, wherein

The interference delete unit, the residual signals addition that each the interference delete unit that is used for will going up the reconstruction signal of an iteration stages respective user and be connected in the front obtains after removing from received signal and disturbing, data-signal after the addition is detected, utilize detected data to generate the estimated value of described user data, and from the data-signal after the described addition, deduct the reconstruction signal that is generated by described user data estimated value, obtain residual signals and send one interference delete unit, back to

And, interference delete unit on each iteration stages of corresponding same subscriber signal, be used for the described reconstruction signal that is generated by described user data estimated value is carried out iteration step by step, and the corresponding described decision unit of the estimated value of the described user data that the afterbody iteration is obtained input adjudicates, and obtains described user's restoring signal;

Described interference delete unit comprises the Nonlinear Processing module, is used for determining according to the confidence level of the current user data that detects the estimated value of described user data.

Described Nonlinear Processing module is the signal to noise ratio according to the iteration sum of series respective user of current interference delete unit correspondence, determines that through judgement still be the estimated value that is directly obtained described user data by described detected data.

The tupe that described Nonlinear Processing module is configured is as follows:

When detected user data sequence is z _{G, p}={ z _{G, p, i}, i=0,1 ..., during N-1, for permanent width of cloth modulation system, through the user data sequence after the Nonlinear Processing ${\tilde{Z}}_{g,p}=\left\{{\tilde{z}}_{g,p,i}\right\},i=\mathrm{0,1},\·\·\·,N-1$ Expression formula be:

Wherein, DEC () represents hard decision, arg () ∈ (π, π] expression calculated complex the main value argument, η _k∈ (π, π] (and k=0,1 ..., 2 ^M-1) be the main value argument of size for the permanent width of cloth modulation constellation points of M, ξ is the threshold value by the signal to noise ratio decision of current iteration sum of series respective user.

The algorithm of described threshold xi is as follows:

$\mathrm{\ξ}=\frac{1}{14}+\frac{3}{{\mathrm{\η}}_2}\·[g+{\log }_{10}(\mathrm{SNR}+{\mathrm{\η}}_1)]$

Wherein, g represents the rank of interference delete iteration, and SNR represents the signal to noise ratio of respective user, η ₁And η ₂Be two and be used for controlling the constant that ξ satisfies 1/14＜ξ＜1/2.

Described interference delete unit is that unique user or one group of users'data signals are detected.

Described testing process comprises that Rake RAKE receives and despreading.

Corresponding to above-mentioned receiver, the present invention and then a kind of multiuser serial interference delete method of reseptance with improved constringency performance is provided, after serial interference delete receiver was received the upward signal that the user sends, the concrete steps of carrying out multiuser serial interference delete were as follows:

Steps A, for a user on the iteration stages, the reconstruction signal and the received signal removal of respective user in the last iteration stages are come the residual signals addition that obtains after each user's of front the interference, data-signal after the addition is detected, detected data are carried out generating after the Nonlinear Processing estimated value of described user data, and from the data-signal after the described addition, deduct the reconstruction signal that is generated by described user data estimated value, obtain residual signals;

Step B, repeating step A, all users' signal all carried out detection on all iteration stages, and the estimated value of each user data that the afterbody iteration is obtained is adjudicated respectively, obtains the restoring signal of respective user;

In the described steps A detected data being carried out Nonlinear Processing, is the estimated value of determining user data according to the confidence level of the current user data that detects.

The described estimated value of utilizing detected data to generate user data is the signal to noise ratio according to current iteration sum of series respective user, determines that through judgement still be the estimated value that is directly obtained described user data by described detected data.

The algorithm of described Nonlinear Processing is as follows:

When detected user data sequence is z _{G, p}={ z _{G, p, 1}, i=0,1 ..., during N-1, for permanent width of cloth modulation system, through the user data sequence after the Nonlinear Processing ${\tilde{Z}}_{g,p}=\left\{{\tilde{z}}_{g,p,i}\right\},i=\mathrm{0,1},\·\·\·,N-1$ Expression formula be:

Wherein, DEC () represents hard decision, arg () ∈ (π, π] expression calculated complex the main value argument, η _k∈ (π, π] (and k=0,1 ..., 2 ^M-1) be the main value argument of size for the permanent width of cloth modulation constellation points of M, ξ is the threshold value by the signal to noise ratio decision of current iteration sum of series respective user.

The algorithm of described threshold xi is as follows:

$\mathrm{\ξ}=\frac{1}{14}+\frac{3}{{\mathrm{\η}}_2}\·[g+{\log }_{10}(\mathrm{SNR}+{\mathrm{\η}}_1)]$

Wherein, g represents the rank of interference delete iteration, and SNR represents the signal to noise ratio of respective user, η ₁And η ₂Be two and be used for controlling the constant that ξ satisfies 1/14＜ξ＜1/2.

Described steps A is that unique user or one group of users'data signals are detected.

Described testing process comprises that Rake RAKE receives and despreading.

Advantage and characteristics that the present invention is main are as follows:

1. the present invention is based on existing serial interference delete structure, be convenient to realize that this structure can reduce the interference of strong user to weak user to greatest extent, can realize multi-user's interference delete accurately and effectively;

2. the recovered part to multipath channel has adopted the lower RAKE receiver of complexity, and the equalization methods that uses in the existing cdma system is the RAKE reception, has kept the existing certain compatibility of cdma system;

3. the Nonlinear Processing module of setting up is used for the user data that will offer reconstructed module is carried out Nonlinear Processing, has reduced the generation of error diffusion phenomenon, has obtained good systematic function.

Description of drawings

Be described in detail in conjunction with the following drawings and understand principle of the present invention, step, characteristics and advantage helping, in the accompanying drawing:

Fig. 1 is the system configuration schematic diagram with multiuser serial interference delete receiver of improved constringency performance of the present invention;

Fig. 2 is interference delete unit ICU among Fig. 1 of the present invention _{(g, p)}The composition structure chart;

Fig. 3 is the flow chart with multiuser serial interference delete method of reseptance of improved constringency performance of the present invention;

Fig. 4 illustrates the bit error rate performance of technical scheme of the present invention under simulation scenarios.

Embodiment

In (grouping) serial interference delete algorithm of time domain, user's detection data confidence level is different in each (grouping) serial interference delete iteration rank.Under the condition of (grouping) serial interference delete algorithmic statement, the rank of iteration is high more, and signal to noise ratio is high more, and user's detection data confidence level is just high more so.Therefore, main thought of the present invention is to set up a nonlinear function, the confidence level of the judgement mode of user's detection data and data is closely connected is in the same place.Like this, make our serial (grouping serial) interference delete algorithm restrain rapidly, receiver can obtain the quite good detecting performance with less iterations.

Below, with reference to Fig. 1 the structure of the multi-user with improved constringency performance (grouping) serial interference delete receiver of the present invention's proposition is described.

The difference of serial interference delete and grouping serial interference delete only is, in the grouping interference delete, the user will divide into groups according to signal to noise ratio, at first the strongest user's group of signal to noise ratio is detected, and successively each group is detected according to the ordering of signal to noise ratio size then.What all users in the group used is the parallel interference deletion, and when certain group detected, delete all users' of group reconstruct data, so what carry out between the group is serial interference delete.Parallel interference deletion in the group can reduce system's time delay, and the serial interference delete between group can reduce the interference of strong user to weak user to greatest extent.If in the grouping serial interference delete algorithm, have only a user in each grouping, so just become the serial interference delete reception.So serial interference delete is a special case of grouping serial interference delete.

Because adopt the structure of (grouping) serial interference delete, thus define a unified structure the interference delete unit (Interference Cancellation Unit, ICU).Because serial interference delete and grouping serial interference delete receiver structure are closely similar, principle is also basic identical, so each interference delete unit in the up serial interference delete receiver of CDMA shown in Figure 1, both can be regarded as unique user had been handled, and also can be regarded as one group of user is handled.For some module I CU among Fig. 1 _{(g, p)}, two inputs are arranged: residual signals E _{G, p}With in the upper level iteration to this user's (group) reconstruction signal I _{G-1, p}ICU _{(g, p)}Three output: I are arranged _{G, p}Provide reconstruction signal, E to this user of next stage iteration (group) _{G, p+1}Provide residual signals,, just use the 3rd output if the detection data of iteration at the corresponding levels are adjudicated to the next user of iteration at the corresponding levels (group)

Here, residual signals E _{G, p}As an input signal of ICU at the corresponding levels unit, being appreciated that into it is that total received signal has deducted the pairing reconstruction signal of the user who has detected, and the difference that obtains.Because detecting the user data that is recovered each time is not entirely accurate certainly, so still keeping the portion of energy of useful user data in this difference.For first ICU unit of the first order of (grouping) serial interference delete, residual error E _1,1Just equal the received signal R of system, for remaining ICU unit, residual error E _{G, p+1}=E _{G, p}+ I _{G-1, p}-I _{G, p}In addition, the one-time detection of finishing all users is exactly the one-level iteration, and promptly each row ICU unit has all been carried out one-time detection and carried out the one-level iteration exactly among Fig. 1.As for reconstruction signal above-mentioned, in the interference delete iterative process, some users are through (Nonlinear Processing of the present invention belongs to a kind of method of part judgement) after hard decision or the Nonlinear Processing, user data obtains all or the recovery of part, these data will be passed through spread spectrum again then, and carry out convolution with channel again, so just obtained reconstruction signal.This reconstruction signal is the part of this user in received signal, also is the interference to other users.

Fig. 2 is unit ICU among Fig. 1 _{(g, p)}The detailed structure view of an embodiment.In this embodiment, when detecting, this ICU unit carries out RAKE (Rake) to subscriber signal earlier and receives processing to user's (group).

At first, the residual signals E of input _{G, p}Will with the upper level iteration in to the present user's that will detect (group) reconstruction signal I _{G-1, p}Addition.Carry out channel equalization by the RAKE technology, then through obtaining detected burst Z after the despreading resume module _{G, p}Before user's data is carried out spread spectrum, multipath reconstruct, use a nonlinear function (Nonlinear Function) user's data to be handled the burst after obtaining handling

Processing by nonlinear function interrelates the user's data fed back and the confidence level of detection, thereby the algorithm of whole serial iteration is restrained at faster speed. Can be used for carrying out the hard decision of data, perhaps be used for producing user's's (group) reconstruction signal I _{G, p}Residual signals E _{G, p+1}Calculation expression be: E _{G, p+1}=E _{G, p}+ I _{G-1, p}-I _{G, p}

ICU shown in Figure 2 _{(g, p)}The Nonlinear Processing module that the unit uses is to interrelate for the user data that will be fed back and the confidence level of the current user data that detects.Obviously, guarantee that at algorithm the progression of serial interference delete is high more under the convergence condition, signal to noise ratio is high more, and the user data confidence level after the despreading is just high more in the ICU module so.When user's data was adjudicated, at first the threshold value that obtains according to calculated in advance obtained decision region and non-decision region.In fact this decision region is exactly the subregion on the signal constellation (in digital modulation), and data drop in the decision region, just thinks that these data of user are credible, can carry out hard decision; If drop on non-decision region, just think that data are insincere, do not keep it constant with regard to not carrying out hard decision.Threshold value can adaptive adjustment decision region and the size of non-decision region.And high more according to the progression of serial interference delete, signal to noise ratio is high more, and the user data confidence level after the despreading is with regard to high more principle in the ICU module so, and in this case, threshold value can be so that decision region enlarges; Otherwise threshold value can so that decision region dwindle.

And the progression of this credibility and iteration is the non-linear relation of a complexity.We set up a nonlinear function and simulate this effect, at first suppose among Fig. 2 through RAKE receive and despreading after detected user data sequence be z _{G, p}={ z _{G, p, i}, i=0,1 ..., N-1 is so for permanent width of cloth modulation such as BPSK, QPSK and 8PSK, through the user data sequence after the nonlinear function processing ${\tilde{Z}}_{g,p}=\left\{{\tilde{z}}_{g,p,i}\right\},i=\mathrm{0,1},\·\·\·,N-1$ Expression formula be:

Wherein, DEC () represents hard decision, and arg () ∈ (π, π] be the main value argument of calculating a plural number.η _k∈ (π, π] (and k=0,1 ..., 2 ^MDoes-1) being size, (may I ask: M represent the received signal amplitude for the main value argument of the permanent width of cloth modulation constellation points of M?), such as η in BPSK _k∈ { 0, π }.ξ is a threshold value by the decision of iteration sum of series signal to noise ratio, and it is modeled as following form:

ξ＝f(g，SNR) (2)

Wherein, g is the rank of interference delete iteration, and SNR is this user's a signal to noise ratio.

As an example, functional expression (2) specific design is become following form:

$\mathrm{\ξ}=\frac{1}{14}+\frac{3}{{\mathrm{\η}}_2}\·[g+{\log }_{10}(\mathrm{SNR}+{\mathrm{\η}}_1)]---\left(3\right)$

Wherein, η ₁And η ₂Be two constants, they are used to control ξ and satisfy condition: 1/14＜ξ＜1/2.See easily,, also reasonably enlarging by the decision region that ξ determined along with the rising of iterations and signal to noise ratio.

Based on above-mentioned receiver structure, the present invention provides multi-user's (grouping) serial interference delete that has improved constringency performance accordingly method of reseptance again, see also Fig. 3, this figure is the flow chart that has multi-user's (grouping) serial interference delete method of reseptance of improved constringency performance among the present invention, and its specific implementation process is as follows:

After step 1, receiver were received the upward signal that the user sends, received signal was admitted to interference delete receiver.Because this receiver is (grouping) serial structure, so on each iteration stages g, the user of front (grouping) ICU _{(g, p)}User's (grouping) ICU with the back _{(g, p+1)}Be cascaded structure, and offer an input of user's (grouping) the residual signals E of back _{G, p+1}, its calculation expression is: E _{G, p+1}=E _{G, p}+ I _{G-1, p}-I _{G, p}

Step 2, each interference delete unit ICU _{(g, p)}Input be residual signals E _{G, p}With in the upper level iteration to this user's (group) reconstruction signal I _{G-1, p}, after these two the input additions, be input to the deconvolution of carrying out multipath channel in the RAKE receiver and handle.

Step 3, RAKE receiver will be carried out despreading to the signal chip after handling.Data after the despreading are carried out the processing of part judgement by the Nonlinear Processing module, and through after this module, a part of believable data have obtained the primary signal estimated value through hard decision, and another part is considered to insecure data and remains unchanged.

Step 4, the output of nonlinear function module

Can input to two modules.If the interference delete iterative process is proceeded, this output will be sent into the signal reconstruction module so, and will be just right Carry out spread spectrum again, and carry out convolution, reconstruct the contribution I of this user (group) in the signal that receiver received with multipath channel _{G, p}

Step 5, according to the uniform definition of interference delete, the detected circulation of finishing of all users just is called the one-level iteration of interference delete.The last residual signals that produces of upper level iteration is directly sent into the next stage iteration, continues on for the interference delete algorithm.If according to system's setting, the number of times of interference delete is enough, and iterative process just finishes so,

Just input to judging module, all data are carried out hard decision, obtain this user's restore data.

Below, specify the performance of multi-user interference delete receiver of the present invention by an example.The analogue system of setting up is as follows:

The common cdma system backward channel of additional CP or ZP is not encoded, and radio frequency carrier frequency is 2GHz, and channel adopts the M.1225 vehicle-mounted A channel model of regulation, the BPSK modulation.Chip transmits according to time slot, 2048 chips of each time slot, and spreading rate is 1.2288Mchip/s.Adopt ideal communication channel to estimate in the emulation.Number of users is 16, spread spectrum coefficient SF=16, and we simulate the HRPD system and use scrambler to distinguish user's the practice, and using length is 2 ⁴²The truncated code of-1 m sequence is as the sign of distinguishing the user.Two coefficients in the above-mentioned formula (3) are set at respectively: η ₁=2, η ₂=98.Adopt the system configuration of serial interference delete.

16 users' average error rate performance as shown in Figure 4, under two criterion situations, the iteration before the 5th is vastly improved the performance of system, to the 7th iteration, algorithm is near convergence.

Theory analysis and emulation prove that all our receiver performance of design is better, and complexity is low, and industrial applicibility is preferably arranged.

Claims (12)

1, a kind of multiuser serial interference delete receiver with improved constringency performance, it is characterized in that, the decision unit that the interference delete unit that comprises the polyphone with at least one iteration stages links to each other with output with afterbody polyphone interference delete unit, wherein

The interference delete unit, the residual signals addition that each the interference delete unit that is used for will going up the reconstruction signal of an iteration stages respective user and be connected in the front obtains after removing from received signal and disturbing, data-signal after the addition is detected, utilize detected data to generate the estimated value of described user data, and from the data-signal after the described addition, deduct the reconstruction signal that is generated by described user data estimated value, obtain residual signals and send one interference delete unit, back to

And, interference delete unit on each iteration stages of corresponding same subscriber signal, be used for the described reconstruction signal that is generated by described user data estimated value is carried out iteration step by step, and the corresponding described decision unit of the estimated value of the described user data that the afterbody iteration is obtained input adjudicates, and obtains described user's restoring signal;

Described interference delete unit comprises the Nonlinear Processing module, is used for determining according to the confidence level of the current user data that detects the estimated value of described user data.

2, receiver as claimed in claim 1, it is characterized in that, described Nonlinear Processing module is the signal to noise ratio according to the iteration sum of series respective user of current interference delete unit correspondence, determines that through judgement still be the estimated value that is directly obtained described user data by described detected data.

3, receiver as claimed in claim 2 is characterized in that, the tupe that described Nonlinear Processing module is configured is as follows:

When detected user data sequence is z _{G, p}={ z _{G, p, i}, i=0,1 ..., during N-1, for permanent width of cloth modulation system, through the user data sequence after the Nonlinear Processing ${\tilde{Z}}_{g,p}=\left\{{\tilde{z}}_{g,p,i}\right\},$ I=0,1 ..., the expression formula of N-1 is:

Wherein, DEC () represents hard decision, arg () ∈ (π, π] expression calculated complex the main value argument, η _k∈ (π, π] (and k=0,1 ..., 2 ^M-1) be the main value argument of size for the permanent width of cloth modulation constellation points of M, ξ is the threshold value by the signal to noise ratio decision of current iteration sum of series respective user.

4, receiver as claimed in claim 3 is characterized in that, the algorithm of described threshold xi is as follows:

$\mathrm{\ξ}=\frac{1}{14}+\frac{3}{{\mathrm{\η}}_2}\·[g+{\log }_{10}(\mathrm{SNR}+{\mathrm{\η}}_1)]$

Wherein, g represents the rank of interference delete iteration, and SNR represents the signal to noise ratio of respective user, η ₁And η ₂Be two and be used for controlling the constant that ξ satisfies 1/14＜ξ＜1/2.

5, receiver as claimed in claim 1 is characterized in that, described interference delete unit is that unique user or one group of users'data signals are detected.

6, receiver as claimed in claim 1 is characterized in that, described testing process comprises that Rake RAKE receives and despreading.

7, a kind of multiuser serial interference delete method of reseptance with improved constringency performance is characterized in that, after serial interference delete receiver was received the upward signal that the user sends, the concrete steps of carrying out multiuser serial interference delete were as follows:

Steps A, for a user on the iteration stages, the reconstruction signal and the received signal removal of respective user in the last iteration stages are come the residual signals addition that obtains after each user's of front the interference, data-signal after the addition is detected, detected data are carried out generating after the Nonlinear Processing estimated value of described user data, and from the data-signal after the described addition, deduct the reconstruction signal that is generated by described user data estimated value, obtain residual signals;

Step B, repeating step A, all users' signal all carried out detection on all iteration stages, and the estimated value of each user data that the afterbody iteration is obtained is adjudicated respectively, obtains the restoring signal of respective user;

In the described steps A detected data being carried out Nonlinear Processing, is the estimated value of determining user data according to the confidence level of the current user data that detects.

8, method as claimed in claim 7, it is characterized in that, the described estimated value of utilizing detected data to generate user data is the signal to noise ratio according to current iteration sum of series respective user, determines that through judgement still be the estimated value that is directly obtained described user data by described detected data.

9, method as claimed in claim 8 is characterized in that, the algorithm of described Nonlinear Processing is as follows:

When detected user data sequence is z _{G, p}={ z _{G, p, i}, i=0,1 ..., during N-1, for permanent width of cloth modulation system, through the user data sequence after the Nonlinear Processing ${\tilde{Z}}_{g,p}=\left\{{\tilde{z}}_{g,p,i}\right\},$ I=0,1 ..., the expression formula of N-1 is:

Wherein, DEC () represents hard decision, arg () ∈ (π, π] expression calculated complex the main value argument, η _k∈ (π, π] (and k=0,1 ..., 2 ^M-1) be the main value argument of size for the permanent width of cloth modulation constellation points of M, ξ is the threshold value by the signal to noise ratio decision of current iteration sum of series respective user.

10, method as claimed in claim 9 is characterized in that, the algorithm of described threshold xi is as follows:

$\mathrm{\ξ}=\frac{1}{14}+\frac{3}{{\mathrm{\η}}_2}\·[g+{\log }_{10}(\mathrm{SNR}+{\mathrm{\η}}_1)]$

Wherein, g represents the rank of interference delete iteration, and SNR represents the signal to noise ratio of respective user, η ₁And η ₂Be two and be used for controlling the constant that ξ satisfies 1/14＜ξ＜1/2.

11, method as claimed in claim 7 is characterized in that, described steps A is that unique user or one group of users'data signals are detected.

12, method as claimed in claim 7 is characterized in that, described testing process comprises that Rake RAKE receives and despreading.

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