Background technology
Along with development of times, people comprise the requirement to communication quality and class of business etc. to the requirement of communication, and are also more and more higher.The third generation (3G) mobile communication system is grown up in order to satisfy this requirement just.It is as basic point of departure with global general-use, system synthesis, and attempt to set up the mobile comprehensive service digital network in a whole world, the function of various mobile communication system such as comprehensive honeycomb, wireless, paging, cluster, mobile data, mobile-satellite, aerial and sea, provide and the professional compatibility of fixed telecommunication network, multiple speech and the non-speech service that quality is suitable, carry out the global roaming of pocket personal terminal, thus realize human dream of anywhere, any time and anyone ideal that communicates.
That most critical is radio transmission techniques (RTT) in the 3-G (Generation Three mobile communication system).The RTT candidate motion that International Telecommunications Union in 1998 collects: except that 6 satellite interface technical schemes, the terrestrial wireless interfacing has 10 schemes, is divided into two big class: CDMA and TDMA (time division multiple access), and wherein CDMA occupies an leading position.In CDMA technology, International Telecommunications Union has accepted 3 kinds of standards at present altogether, i.e. TD-SCDMA (TD SDMA) standard of the CDMA 2000 of the W-CDMA (Wideband Code Division Multiple Access (WCDMA)) of Europe and Japan, the U.S. and China.
Compare with other 3G (Third Generation) Moblie standard, TD-SCDMA has adopted many exclusive advanced technologies, and all has outstanding advantage aspect the technology, economic two.TD-SCDMA adopts time division duplex (Time Division Duplex, abbreviation TDD), smart antenna (Smart Antenna), joint-detection technology such as (Joint Detection), availability of frequency spectrum height, can solve the problem of high population density area frequency resource anxiety, and have potential advantages aspect the multimedia services such as asymmetric mobile data such as internet browsing and video request program.
TD-SCDMA and other cdma systems are with the same, it all is a kind of CDMA multi-user mobile system, different channels adopts the mode of spread spectrum to carry out message transmission by different timeslices or by different binary code sequences under same frequency, the information of any one channel transmits and all can cause interference to other channels like this, all is a kind of noise concerning the reception of other channels.In cdma system, the address code sequence that each channel all has own distinctive confession to discern mutually.And also should be mutually orthogonal between the spectrum-spreading address code sequence of each channel.The requirement of this orthogonality all is consistent concerning any multi-address system.If channel is a desirable linear session frequency indiffusion system, simultaneity factor inside has strict synchronized relation again, guarantees that then the orthogonality of each station address intersymbol still can realize.
And actual mobile telecommunication channel is typical random time-varying channel, wherein exists the frequency diffusion of the randomness that is produced by Doppler effect, reaches the time diffusion of the randomness that is produced by the multipath transmisstion effect.The former can make received signal produce frequency selective fading, and promptly received signal different spectral component has different random fluctuation variations.The latter makes the decline of received signal generation time selectivity, and promptly received signal level can have different random fluctuations to change in time.Described these 2 kinds of declines also will reduce the capacity of system significantly except the performance of meeting severe exacerbation system.Particularly the diffusion of the time of channel makes signal can not arrive acceptance point simultaneously, and the signal between same user's adjacent-symbol is overlapped each other, and produces intersymbol interference (ISI); The diffusion of the time of channel also can worsen multiple access interference (MAI) in addition, this is because when be zero the relative time delay between the different user signal, its orthogonality is easy to guarantee, any orthogonal code can be used, but when the relative time delay between signal is non-vanishing, still keep its orthogonality will become very difficult; Moreover same frequency sub-district adjacent or at a distance, no matter be signal from its base station or subscriber terminal equipment, also can form neighbor cell or interchannel interference (ACI) to the base station of this locality or the signal of subscriber terminal equipment.
For the purpose of image, claim that the auto-correlation function value at spreading code initial point place is the main peak of correlation function; Claim the auto-correlation outside the initial point, or cross-correlation function value is the submaximum of correlation function.
Therefore the interference in the cdma system comes from the relevant submaximum of spreading code, intersymbol interference (ISI) is from the autocorrelative submaximum of spreading code, multiple access disturbs (MAI) submaximum from cross-correlation, and neighbor cell or interchannel interference (ACI) come from the non-orthogonal relevant submaximum that brings of the signal of adjacent or sub-district, distant place usually.
As shown in Figure 1, be the example of a typical cell mobile communication systems.This system is by a plurality of sub-districts 100
1-100
z(100) constitute, a base station (Base Station) 101 is wherein respectively arranged in each sub-district
1-101
z(101), the subscriber terminal equipment (User Equipment is abbreviated as UE) 102 that in this sub-district service range, has some simultaneously
1-102
K(102).Each subscriber terminal equipment 102 by with affiliated Serving cell 100 in base station 101 keep being connected, finish and other communication equipment between communication function.The channel that communicates between subscriber terminal equipment 102 and the base station 101 is called as up channel from the channel of terminal equipment 102 101 directions to the base station, and 101 channels to terminal equipment 102 directions are called as down channel from the base station.
As shown in Figure 2, be the frame structure schematic diagram of TD-SCDMA system.This structure is according to providing in low spreading rate time division duplex (LCR-TDD) pattern (1.28Mcps) among 3G collaborative project (3GPP) the standard TS 25.221 (Release 4).The spreading rate of TD-SCDMA system is 1.28Mcps, and the length of each radio frames (Radio Frame) 200 is 10ms, and is divided into two subframes 201 that structure is identical
0, 201
1(201), the length of each subframe is 5ms, i.e. 6400 chips.Wherein, the subframe 201 in each TD-SCDMA system can be divided into 7 time slots again (TS0~TS6) 202
0-202
6, two pilot time slots: descending pilot frequency time slot (DwPTS) 203 and uplink pilot time slot (UpPTS) 205, and protection interval (Guard) 204.Further, the TS0 time slot 202
0Be used to bearing system broadcast channel and other possible downlink traffic channel; And TS1~TS6 time slot 202
1-202
6Then be used to carry the uplink and downlink Traffic Channel.It is synchronous that uplink pilot time slot (UpPTS) 205 and descending pilot frequency time slot DwPTS time slot 203 are used to set up initial uplink and downlink respectively.TS0~TS6 time slot 202
0-202
6Length is 0.675ms or 864 chips, wherein comprise data segment Data Partl (208) and Data Part2 (210) that two segment lengths are 352 chips, and a middle segment length is the training sequence of 144 chips---in lead sign indicating number (Midamble) sequence 209.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.The protection that DwPTS time slot 203 comprises 32 chips at interval 211 and one long be descending synchronous code (SYNC-DL) code word 206 of 64 chips, its effect is cell ID and sets up initial synchronisation; And the UpPTS time slot comprise one long be uplink synchronous code (SYNC-UL) code word 207 of 128 chips, subscriber terminal equipment utilizes it to carry out relevant up access procedure.At TS1~TS6 time slot 202
1-202
6Between a Switching Point (transfer point) 212 is arranged.When the up-downgoing ratio was 3: 3, Switching Point (transfer point) 212 was positioned at TS3~TS4 time slot 202
3-202
4Between, at this moment, the employed up Dedicated Traffic Channel of user terminal is dispensed on TS1~TS3 time slot 202
1-202
3In, the descending TS4~TS6 time slot 202 that then is distributed in usually
4-202
6In.
As shown in Figure 3, the base station 101
1, base station 101
2With base station 101
3Be synchronous, promptly while transmitting downstream synchronous code (SYNC-DL) is respectively SYNC-DL
1(301), SYNC-DL
2(302) and SYNC-DL
3(303); Sub-district 100
1In subscriber terminal equipment 102
1After delay after a while, receive base station 101
1The descending synchronous code SYNC-DL that sends
1(304); Because base station 101
2Apart from terminal equipment 102
1More farther, terminal equipment 102
1Receive base station 101
2The SYNC-DL that is sent
2(302) can be more a little later; Simultaneously, SYNC-DL
2(302) signal incoming terminal equipment 102
1Shi Huiyu SYNC-DL
1(304) overlapping of back, thus the reception of this lap is formed interference; Terminal equipment 102
1Emission uplink synchronous code SYNC-UL after postponing a period of time
1(305), delay base station 101 in the time of one section
1Received this SYNC-UL
1(306); Base station 101
3Be and base station 101
1The base station that distance is farther; If described distance is enough far away, base station 101
3The SYNC-DL that is launched
3(303) arrive base station 101
1The time, meeting and base station 101
1Search SYNC-UL
1(305) search window is overlapping, and therefore to signal SYNC-UL
1(306) form interference, especially SYNC-UL
1(306) part of signal front, the interference that is subjected to is bigger; When base station 101
3With base station 101
1Between when having the direct projection path, in the base station 101
1The place, interference signal SYNC-DL
3(303) power can be far longer than the signal SYNC-UL of terminal equipment
1(306).
As shown in Figure 4, provided SYNC-DL
3(303) signal is to SYNC-UL
1(306) reception forms an example of disturbing.In this example with base station 101
1The SYNC-UL that receives
1(306) initial position is an initial point, uses uplink synchronous code SYNC-UL
1As the local code sequence, slide with respect to the signal that receives, calculate the absolute value of correlation; Wherein, the local code sequence is called correlation delay, SYNC-DL with respect to the delay that signal slip between is produced
3(303) amplitude is SYNC-UL
1(306) 5 times, and SYNC-DL
3(303) arrive base station 101
1During the place, 37 chips of rear section and SYNC-UL
1(306) 37 of forward part chips are overlapping.The absolute value 400 of the correlation at initial point 0 place is the absolute value of auto-correlation main peak among Fig. 4, and the absolute value of other all non-zero correlations is the absolute value of relevant submaximum.As can be seen from Figure 4, under strongly disturbing situation, main peak 400 is difficult to be distinguished from correlated results, especially Zui Da relevant submaximum 401 its numerical value even greater than main peak 400.
Code division multiple access system is the system of a self-interference, forms mutually between the intrasystem signal and disturbs, and therefore, how correctly to parse the real information of institute's receive channel in disturbed signal, is the important topic that system faces.
In the prior art, between the energy value of each chip of the signal that receives, and be used to this signal is carried out despreading and be equal weight between each chip of the local code sequence used.Yet in the practical communication environment, the interference profile that the various piece of a burst is suffered is also inequality, and the interference that the part that has is subjected to is many, and the interference that some places are subjected to is less.
In cdma system, information data can use spreading code that it is carried out spread spectrum before emission.The method of spread spectrum is to use by spread spectrum data to multiply by spreading code.Spreading code can equivalence becomes by+1 and-1 sequence that is constituted.Suppose that spread spectrum code sequence C is [+1 ,-1 ,+1 ,-1], and be B by the data of spread spectrum, the burst behind the spread spectrum then, promptly the B sequence is [+B ,-B ,+B ,-B].
The signal A sequence of supposing one other channel is [+A ,+A ,-A ,-A], and this A sequence is to use local code sequence E[+1 ,+1 ,-1-1] data A is carried out spread spectrum obtain.Suppose that because time delay, last 1 chip in the B sequence and the 1st chip of A sequence are overlapping, the signal that receives of receiving terminal then, promptly the S sequence is [+B ,-B ,+B ,-B+A ,+A ,-A ,-A].
When receiving terminal will receive data A, use local code sequence E[+1 ,+1 ,-1-1], the S sequence is carried out despreading, the relative S sequence of local code sequence E is slided; Herein, when correlation delay is 3, the A sequence alignment in local code sequence E and the signal S sequence, calculate correlation, promptly earlier local code sequence E is multiplied each other in twos with the corresponding position step-by-step of S sequence, addition again, promptly (B+A) * 1+A * 1+ (A) * (1)+(A) * (1)=-B+4A; Divided by the length 4 of sequence E, then despreading result is A-B/4 then.As seen,, will occur anti-phasely, the situation of despreading mistake will take place when the amplitude of B during greater than 4 times of A.
On the other hand, when visible prior art uses the local code sequence that burst is carried out despreading, be to wait power between each chip.In the burst, each several part is subjected to the distribution of interference of other signals and inequality but in fact.
Obviously, the 1st of the A sequence the chip is subjected to the interference that the B sequence causes; When the amplitude of B was far longer than A, this interference was strong; And 3 chips are not subjected to the interference of B after the A sequence.And this point, in the example depicted in fig. 3 also can be apparent: base station 101
1The uplink synchronous code SYNC-UL that receives
1(306), the part of its front has been subjected to coming from base station 101
3The SYNC-DL that is launched
3(303) very strong interference, and remaining part is not subjected to the interference of this signal; Equally, terminal equipment 102
1The descending synchronous code SYNC-DL that receives
1(304), the part of its back has been subjected to coming from base station 101
2The SYNC-DL that is launched
2(302) than strong jamming, the part of its front then is not subjected to the interference of this signal, and, terminal equipment 102
1The closer to the base station 101
1, SYNC-DL
1(304) the part that is interfered later is few more.
Embodiment
Below by Fig. 5~Fig. 9, introduce an embodiment of the present utility model in detail, so that further understand content of the present utility model.
As shown in Figure 5, the utility model provides to reduce in a kind of code division multiple access system and receives the method for disturbing, and it comprises following steps:
Required array and parameter in step 1, the initialization computational process:
Step 1.1, initialization length are the array C of G, this array C be used for depositing receiver receives will be by the signal of despreading, G is that this will be by the length of the signal of despreading;
Step 1.2, initialization length are the array E of L, and this array E is used for depositing the local code sequence, and L is the length of local code sequence;
Step 1.3, initializing variable Option, S, H
1, H
2, D
1, D
2, q, Result_R and Result_Q;
Step 1.3.1, the value that Option is set are 1 or 2, and being used for the right to choose value sequence is sequence C weighting to the received signal or to local code sequence E weighting;
Step 1.3.2, the value of S is set between 0 to 2, representative value is 1, because may still exist part to disturb among the result after weighting is relevant, and the pairing weights sum of this correlated results also may be very little, to obtain the despreading result be will be divided by described weights sum because correlated results carries out normalization, and this very little inverse with value will amplify the part interference that still exists, therefore, when described parameter S is used for regulating normalization, this and the influence that is worth;
Step 1.3.3, H is set
1, H
2, whether effectively it is respectively applied for judges correlation Lower Threshold and Upper threshold;
Step 1.3.4, D is set
1, D
2, it is respectively local code sequence E carries out correlation delay with respect to burst C minimum value and maximum;
Step 1.3.5, q=D is set
1, the correlation delay variable that q is adopted when representing to carry out correlation computations, its span is [D
1, D
2];
Step 1.3.6, Result_R, Result_Q are set, it returns the despreading result after the normalization respectively, and the delay between pairing local code sequence E and the burst C;
Step 1.4, initialization length are (D
2-D
1+ 1) array Y and R, array R are used for leaving in the process that correlation delay q changes, the correlated results sequence that calculates, and numerical value Y is used to deposit the sequence of the weights sum of described correlated results correspondence;
The value of step 2, judgement parameter Option is 1 or 2:
If Option=1, then execution in step 3, promptly be equivalent to the weights sequence that will be initialised and be provided with burst C is weighted;
If Option=2, then execution in step 4, promptly be equivalent to the weights sequence that will be initialised and be provided with local code sequence E is weighted;
Step 3, initialization length are the weights sequence array W of G;
Step 3.1, W is set
i, 0≤W wherein
i≤ 1, i=1,2 ..., G;
Step 3.2, calculate when correlation delay is q, the weighting correlation that burst C and local code sequence E right to use value sequence W are weighted, and deposit the result in R
Q-D1+1, promptly the sequence E of sequence W, C and process q position delay multiplies each other and addition by the position of correspondence:
Calculate the weights sum that has been used in the correlation computations, and deposit Y in
Q-D1+1, that is:
This weights sum will be used to correlated results is carried out normalization; Wherein, the span of i be 1 and 1+q in the minimum value of maximum in q+L and the G; If i<0 or i>G, then W
iAnd C
iAll value is 0; If i-q<0 or i-q>L, then E
I-qValue is 0; ∑ is represented summation, and min represents to minimize, and max represents maximizing;
Step 3.3, change correlation delay q and with it as next retardation, judge whether that all delays had all carried out correlation computations; That is: q=q+1 is set, judges that more whether q is greater than D
2:
If q≤D
2, then return step 3.2, continue next retardation is carried out correlation computations;
If q>D
2, then execution in step 5;
Step 4, initialization length are the weights sequence array W of L;
Step 4.1, W is set
i, 0≤W wherein
i≤ 1, i=1,2 ..., L;
Step 4.2, calculate when correlation delay is q, the weighting correlation that burst C and local code sequence E right to use value sequence W are weighted, and deposit the result in R
Q-D1+1, promptly the sequence E and the sequence W of sequence C and process delay multiply each other and addition by the position of correspondence:
Calculate the weights that have been used in the correlation computations and, and deposit Y in
Q-D1+1, that is:
This weights sum will be used to correlated results is carried out normalization; Wherein, the span of i be 1 and 1+q in the minimum value of maximum in q+L and the G; If i<0 or i>G, then C
iValue is 0; If i-q<0 or i-q>L, then W
I-qAnd E
I-qAll value is 0;
Step 4.3, change correlation delay q and with it as next retardation, and judge whether that all delays had all carried out correlation computations; That is: q=q+1 is set, judges that more whether q is greater than D
2:
If q≤D
2, then return step 4.2, continue next retardation is carried out correlation computations;
If q>D
2, then execution in step 5;
Step 5, judge whether contain the signal that effective use local code sequence E carries out spread spectrum among the burst C, promptly judge whether to exist R
iSatisfy H
1≤ | R
i|≤H
2, i=1 wherein, 2 ..., D
2-D
1+ 1, " || absolute value is asked in expression:
If not, then execution in step 5.1: returning correlated results is 0, that is: Result_R=0 is set, and returns Result_R;
If then execution in step 5.2: in the effective correlated results that calculates, seek out the value of absolute value maximum, carry out normalized, and it is returned as last despreading result, and return the value of the pairing correlation delay q of this correlated results simultaneously, it comprises following steps:
Step 5.2.1, in array R, seek and satisfy H
1≤ | R
i|≤H
2R under the condition
iMaximum, and deposit it in Result_R, i=1 wherein, 2 ..., D
2-D
1+ 1;
Step 5.2.2, with the R that stores among the Result_R
iPairing i value deposits Result_Q in;
Step 5.2.3, initialization also are provided with variable V, if Y
Result_QBe zero, V=L then is set; Otherwise V=Y is set
Result_QResult_R=Result_R * S * L ÷ V is set; Result_Q=Result_Q+D is set
1-1; Return Reault_R and Result_Q.
In the step 3.1 in the foregoing description, the W in the weights sequence is set
iValue comprises following steps:
Step 3.1.1, respectively measure and the estimated signal sequence in C
iSuffered interference;
Step 3.1.2, according to C in the burst
iThe corresponding W that is provided with of suffered interference
i, if C
iThe interference that is subjected to is bigger, then W
iBe set to the smaller value in 0 to 1 scope; If C
iThe interference that is subjected to is less, then W
iBe set to the higher value in 0 to 1 scope, wherein, i=1,2 ..., G.
Among the above-mentioned steps 3.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, wherein, i=1,2 ..., G.
In the step 3.1 in the foregoing description, to W in the weights sequence
iThe setting of value also can may further comprise the steps:
The transmit leg of main interference signal is by the emission information of this interference signal of recipient of signaled burst C among step 3.1.1, the burst C;
The position that this signal of emission information calculations of the main interference signal that the signaling that step 3.1.2, basis receive is represented is occurred in burst C, the corresponding W that is provided with
i, if C
iSuffered interference is bigger, then W
iBe set to the smaller value in 0 to 1 scope; If C
iSuffered interference is less, then W
iBe set to the higher value in 0 to 1 scope, wherein, i=1,2 ..., G.
Among the above-mentioned steps 3.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, wherein, i=1,2 ..., G.
In addition, in the step 3.1 in the foregoing description, W in the weights sequence
iThe setting of value also can comprise following steps by the recipient's of burst C upper layer module configuration:
Step 3.1.1, measurement are also judged the position that high reject signal occurred among the burst C;
Step 3.1.2, corresponding W the position of high reject signal appears, in burst C
iBe set to the smaller value in 0 to 1 scope; And other positions among the burst C, corresponding W
iBe set to the higher value in 0 to 1 scope, wherein, i=1,2 ..., G.
Among the above-mentioned steps 3.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, wherein, i=1,2 ..., G.
Further, in the TD-SCDMA system, if the high reject signal among the burst C is the descending synchronous code SYNC-DL of other sub-districts, and the local code sequence is when being uplink synchronous code SYNC-UL, then described step 3.1, weights sequence W comprises following steps by the typical method of the recipient's of burst C upper layer module configuration:
Step 3.1.1, in burst C, find the position of causing the descending synchronous code SYNC-DL of interference to occur, and determine the chip position among the pairing burst C of last chip that this descending synchronous code SYNC-DL occurs it;
Step 3.1.2, to all the chip C before the position among the determined burst C among the step 3.1.1
i, corresponding weights W
iAll be set to the smaller value in 0 to 1 scope; And at thereafter all chip C
i, corresponding weights W
iAll be set to the higher value in 0 to 1 scope, wherein, i=1,2 ..., G.
Among the above-mentioned steps 3.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, wherein, i=1,2 ..., G.
In the step 4.1 in the foregoing description, weights sequence W value is set comprises following steps:
Step 4.1.1, respectively measure and the estimated signal sequence in C
iSuffered interference;
Step 4.1.2, according to C in the burst
iThe corresponding W that is provided with of suffered interference
I-q, if C
iSuffered interference is bigger, then W
I-qBe set to the smaller value in 0 to 1 scope; If C
iSuffered interference is less, then W
I-qBe set to the higher value in 0 to 1 scope, wherein, i-q=1,2 ..., L.
Among the above-mentioned steps 4.1.2, described W
I-qThe representative value of the smaller value in 0 to 1 scope is 0; Described W
I-qThe representative value of the higher value in 0 to 1 scope is 1, wherein, i-q=1,2 ..., L.
In the step 4.1 in the foregoing description, weights sequence W value is set comprises following steps:
The transmit leg of main interference signal is by the emission information of this interference signal of recipient of signaled burst C among step 4.1.1, the burst C;
The position that this signal of emission information calculations of the main interference signal that the signaling that step 4.1.2, basis receive is represented is occurred in burst C, the corresponding W that is provided with
I-q, if C
iSuffered interference is bigger, then W
I-qBe set to the smaller value in 0 to 1 scope; If C
iSuffered interference is less, then W
I-qBe set to the higher value in 0 to 1 scope, wherein, i-q=1,2 ..., L.
Among the above-mentioned steps 4.1.2, described W
I-qThe representative value of the smaller value in 0 to 1 scope is 0; Described W
I-qThe representative value of the higher value in 0 to 1 scope is 1, wherein, i-q=1,2 ..., L.
In the step 4.1 in the foregoing description, the setting of weights sequence W also can be by the recipient's of burst C upper layer module configuration, and the weights sequence W that upper layer module disposed can be not change with the variation of lagged variable q, and it comprises following steps:
Step 4.1.1, initialization also are provided with variable f, wherein, and 1≤f≤L;
Step 4.1.2, at weights sequence W
iIn, when 1≤i≤f, W
iBe set to the smaller value in 0 to 1 scope; When f<i≤L, W
iBe set to the higher value in 0 to 1 scope, i=1,2 ..., L.
Among the above-mentioned steps 4.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, i=1, and 2 ..., L.
Further, above-mentioned step 4.1.2 also can be: at weights sequence W
iIn, when 1≤i≤f, W
iBe set to the higher value in 0 to 1 scope; When f<i≤L, W
iBe set to the smaller value in 0 to 1 scope, i=1,2 ..., L.
Among the above-mentioned steps 4.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, i=1, and 2 ..., L.
Further, in the TD-SCDMA system, if the interference signal among the burst C is the descending synchronous code SYNC-DL of other sub-districts, when the local code sequence is uplink synchronous code SYNC-UL, in the then described step 4.1, weights sequence W comprises following steps by the typical method of the recipient's of burst C upper layer module configuration:
Step 4.1.1, initialization also are provided with variable:
, j=1 wherein, 2 ..., 8;
Step 4.1.2, at weights sequence W
iIn, when 1≤i≤f, W
iBe set to the smaller value in 0 to 1 scope; When f<i≤L, W
iBe set to the higher value in 0 to 1 scope, i=1,2 ..., L.
Among the above-mentioned steps 4.1.1, preferred, described j value is 2, then
Among the above-mentioned steps 4.1.2, described W
iThe representative value of the smaller value in 0 to 1 scope is 0; Described W
iThe representative value of the higher value in 0 to 1 scope is 1, i=1, and 2 ..., L.
According to above-mentioned steps 4.1 described collocation methods, when j equals 2, W
iValue be 0 or 1 o'clock, be equivalent to and only adopt half SYNC-UL sign indicating number sequence of back that signal is carried out despreading.
Fig. 6 shows the modular structure figure that is applied to be weighted to the received signal in the cdma system despreading, corresponding to Option=2 among Fig. 5, promptly is equivalent to the part that right to use value sequence W is weighted local code sequence E.Burst 800 modules receive and have stored the burst C that receives, and element among the C are outputed to serial shift registers 801 modules chronologically; Weights series generates 812 modules and generates weights sequence W, and with W and line output; The local code sequence generates 803 modules and generates local code sequence E, and with E and line output; After the multiplier 814 of respective numbers calculates the product of each respective element in each respective element and local code sequence E among the weights sequence W, further the multiplier 815 by respective numbers multiplies each other with current each respective element that leaves in serial shift registers 801 modules of burst C, afterwards, output to summation 816 modules and sue for peace, output to weighting sequence of correlation values 807 modules afterwards; Meanwhile, the weights sequence generates element among the weights sequence W that 812 modules export and also will output to another one 818 modules of suing for peace and sue for peace, and outputs to weights and sequence 809 modules afterwards; The sequence that weights and sequence 809 modules are preserved is Y; The sequence that weighting sequence of correlation values 807 modules are preserved is R.
The variation of the correlation delay q that is adopted during correlation computations in the step 4.3 is by burst 800 modules output signal sequence C chronologically, and then makes the C sequence generate local code sequence E that 803 modules are produced with respect to the local code sequence by serial shift registers 801 modules to slide and realize; In two inputs of each multiplication in the multiplier 814, the sequence number that comes from each element in each element and local code sequence E among the weights sequence W is identical.The every slip of data in serial shift registers 801 modules once, weights and sequence 809 modules and weighting sequence of correlation values 807 modules are just preserved once current result of calculation respectively.
Fig. 7 shows the modular structure figure that is applied in the CMDA system weighting correlated results be carried out normalized.In the upper-layer configured 823 module execution in step 1.3 to parameter S, H
1And H
2Setting, and with H
1And H
2Output to maximum value search 820 modules, S is outputed to normalization 822 modules; The sequence R that is preserved in maximum value search 820 block search weighting sequence of correlation values 807 modules seeks out the R value at H
1And H
2Between maximum, and the result of this search outputed to route searching result 821; Maximum value search 820 modules are exported to weights and sequence 809 modules with the R value pairing element sequence number in sequence that searches simultaneously, and weights and sequence 809 modules are exported to normalization 822 modules according to this sequence number with the pairing weights sum of this maximum; Normalization 822 modules are carried out normalization according to the weights sum that parameter S, weights and sequence 809 modules of upper-layer configured 823 block configuration provide to the R value that maximum value search 820 modules are provided, and with 824 outputs of final correlated results.If maximum value search 820 block search are to the R value that satisfies condition, then route searching result 821 is the value of the correlation delay q between pairing burst C of this R value and the local code sequence E; If do not search the R value that satisfies condition, then route searching result 821 is " not finding ".
Fig. 8 and Fig. 9 have provided respectively and have used method provided by the utility model effectively to reduce SYNC-DL
3(303) signal is to SYNC-UL
1(306) reception forms 2 examples disturbing.In two examples all with base station 101
1The SYNC-UL that receives
1(306) initial position is an initial point, uses uplink synchronous code SYNC-UL
1As local code sequence E, slide with respect to the burst C that receives, calculate the absolute value of correlation; Wherein, SYNC-DL
3(303) amplitude is SYNC-UL
1(306) 5 times, and SYNC-DL
3(303) arrive base station 101
1During the place, 37 chips of rear section and SYNC-UL
1(306) 37 of forward part chips are overlapping.Ordinate among the figure is the absolute value of sequence R.
Corresponding to the foregoing description, in Fig. 8, Option is set to 2 in the step 1; F among the step 4.1.1 is set to 2, and promptly the equal value of the first two of weights sequence W/one is 0, and back 1/2nd equal values are 1.As can be seen from Figure 8, even under strongly disturbing situation, main peak 600 also can be distinguished from correlated results, and its value is greater than the relevant submaximum 601 of maximum; Simultaneously, other relevant submaximums are obviously weakened, and promptly most interference signals are by filtering.
Corresponding to the foregoing description, in Fig. 9, Option is set to 1 in the step 1; And in the step 3.1, among the burst C corresponding to abscissa be 40 chip places before all parts, the equal value of element among its corresponding weights sequence W is 0; The element value of the remainder among the weights sequence W is 1.As can be seen from Figure 9, under strongly disturbing situation, correlated results is not interfered, and main peak 700 is easy to be distinguished, and interfere information is by filtering.
Below by a specific embodiment, compare with background technology, further specify the utility model:
In cdma system, information data can use spreading code that it is carried out spread spectrum before emission.The method of spread spectrum is to use by spread spectrum data to multiply by spreading code.Spreading code can equivalence becomes by+1 and-1 sequence that is constituted.Suppose that spread spectrum code sequence C is [+1 ,-1 ,+1 ,-1], and be B by the data of spread spectrum, the burst behind the spread spectrum then, promptly the B sequence is [+B ,-B ,+B ,-B].
The signal A sequence of supposing one other channel is [+A ,+A ,-A ,-A], and this A sequence is to use local code sequence E[+1 ,+1 ,-1-1] data A is carried out spread spectrum obtain.Suppose that because time delay, last 1 chip in the B sequence and the 1st chip of A sequence are overlapping, the signal that receives of receiving terminal then, promptly the S sequence is [+B ,-B ,+B ,-B+A ,+A ,-A ,-A].
In background technology, when receiving terminal will receive data A, use local code sequence E[+1 ,+1 ,-1-1], the S sequence is carried out despreading, the relative S sequence of local code sequence E is slided; Herein, when correlation delay is 3, the A sequence alignment in local code sequence E and the signal S sequence, calculate correlation, promptly earlier local code sequence E is multiplied each other in twos with the corresponding position step-by-step of S sequence, addition again, promptly (B+A) * 1+A * 1+ (A) * (1)+(A) * (1)=-B+4A; Divided by the length 4 of sequence E, then despreading result is A-B/4 then.As seen,, will occur anti-phasely, the situation of despreading mistake will take place when the amplitude of B during greater than 4 times of A.
And adopt the utility model method, can reduce the weights of the 1st chip of local code sequence E by the method for weighting, and then reduce of the interference of B sequence the A sequence; It is [w that weights sequence W promptly is set
1, w
2, w
3, w
4], w wherein
1Be taken at the smaller value in 0 to 1 scope, w
2, w
3And w
4Be taken at the higher value in 0 to 1 scope.Right to use value sequence W is to local code sequence E weighting, and the local code sequence E after the weighting is [w
1, w
2,-w
3,-w
4].When correlation delay is 3, use the local code sequence E after the weighting that the S sequence that receives is carried out despreading, correlated results be (B+A) * w
1+ A * w
2+ (A) * (w
3)+(-A) * (w
4)=A * (w
1+ w
2+ w
3+ w
4)-B * w
1Again divided by weights sum (w
1+ w
2+ w
3+ w
4), the result who obtains the weighting despreading is A-B * w
1÷ (w
1+ w
2+ w
3+ w
4).As can be seen, because w
1Be taken at the smaller value in 0 to 1 scope, so even the amplitude of B is far longer than A, the suffered interference of despreading result also can be very little; And special, work as w
1When getting representative value 0, the despreading result will not be subjected to any interference.
The method of above-mentioned method for local code sequence E is weighted, in addition, the utility model also can be weighted burst S.The weights sequence W that be provided with this moment is [w
1, w
2, w
3, w
4, w
5, w
6, w
7], will position corresponding weights: the w that A sequence and A sequence may be subjected to larger interference can not appear in the S sequence
1, w
2, w
3And w
4Be set to the smaller value in 0 to 1 scope, get representative value 0 herein; The weights that the A sequence is interfered the part correspondence less: w
5, w
6And w
7Be set to the higher value in 0 to 1 scope, get representative value 1 herein.Then the burst S after the weighting is [0,0,0,0 ,+A ,-A ,-A], and being easy to calculate correlated results is 3A.In the time of the A sequence alignment among local code sequence E and the sequence S, pairing weights sequence is [w
4, w
5, w
6, w
7], i.e. [0,1,1,1], then weights and be 3, therefore with correlated results 3A divided by after 3, promptly correct despreading goes out data A.
Therefore the utility model is equivalent to reduce or removes a part of burst or the influence of a part of local code sequence in despreading is calculated, and when the interference that is subjected to is very strong, can improve the correctness and the reliability of despreading.For example in the TD-SCDMA system, when the descending synchronous code SYNC-DL of the adjacent base station that is occurred received the situation of the strong interference that uplink synchronous code SYNC-UL caused to this cell base station, effect of the present utility model was very tangible; Because this moment, the energy of SYNC-DL is far longer than the energy of SYNC-UL, and just disturbs the part of SYNC-UL front, if by existing decoding technology, SYNC-UL can't be by correct despreading; And in a sub-district, the uplink synchronous code SYNC-UL number that the base station received simultaneously is also few, be generally 1, even this means that the front is subjected to the strong part of disturbing in the uplink synchronous code SYNC-UL signal that receives of deletion base station, and only to the part despreading of back, but can be correctly reliably despreading go out information.
A kind of device that the weighting correlated results is carried out normalized that the utility model provides, simply, be easy to realize, made full use of the interference profile information in the sign indicating number sequence of received signal, with the flexible setting of the weights that correlation computations is weighted, reached and reduced the purpose that receives interference.
Though above described the utility model by embodiment, those of ordinary skills know, the utility model has many distortion and variation and does not break away from spirit of the present utility model, appended claim will comprise these distortion and variation.