CN1373576A - Fast capture method and device for reverse random access channel - Google Patents
Fast capture method and device for reverse random access channel Download PDFInfo
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Abstract
A fast capture method and device for reverse random access channel for WCDMA system is characterized by use of Hadamard transform instead of traditional active association integrator, resulting in high speed and less hardware resource.
Description
(1) technical field:
The invention belongs to 3G (Third Generation) Moblie Wideband Code Division Multiple Access (WCDMA) (WCDMA) technical field, relate in particular to a kind of quick capturing method and device of reverse random access channel.
(2) background technology:
Wideband Code Division Multiple Access (WCDMA) (WCDMA) is Radio Transmission Technology (RTT) scheme that 3-G (Generation Three mobile communication system) standardization body (3rd GenerationPartnership Project (3GPP)) proposes.Catching of frequency expansion sequence is first function that receiver need be finished in the CDMA mobile communication systems, only carried out catching and following the tracks of of frequency expansion sequence, make to send the big code phase of frequency expansion sequence consistent with the code phase of local frequency expansion sequence (synchronously), could realize correct data demodulates.In actual communication systems, because the influence of multiple access interference, noise jamming and multipath effect, quick and effective frequency expansion sequence is caught and is become very difficult.Therefore, fast and effectively the frequency expansion sequence catching method is one of key technology that realizes Wideband Code Division Multiple Access (WCDMA) communication.
The catching of frequency expansion sequence is meant frequency expansion sequence that receiver receives and the phase place initial synchronisation between the local frequency expansion sequence, its importance in spread spectrum system is not only because catching and being the prerequisite of data demodulates synchronously of frequency expansion sequence is the first step of system's operation; And because the unknown phase interval that the frequency expansion sequence that receiver receives is spoken between the local frequency expansion sequence is bigger usually, and it is longer to search for these required times fully, therefore, how to obtain fast and effectively synchronously, be a key index of system.Therefore, the main performance index of catching is capture time and acquisition probability, and its performance will influence power system capacity.
Any one frequency expansion sequence grabber, its taproot unit all is a detector, whether accurately this detector can be relevant or noncoherent (demodulation carrier wave).Detector adopts the correlation intergal device to realize usually, and the correlation intergal device can adopt passive integrator (as matched filter) or active correlation intergal device (removing correlator as integration) to realize again.Output result to detector can adopt different decision rule (as Bayes (Bayes) criterion, Newman-Pearson (Neyman-Pearson) criterions etc.) judge whether the frequency expansion sequence grabber has captured correct phase point, different decision rule has determined to be used as in the frequency expansion sequence grabber whether the choosing of threshold value of acquisition success of judgement frequency expansion sequence.Each used time of detection of detector can be that fix or variable in the frequency expansion sequence grabber.Further say, after detecting for the first time, can also verify that checking is in order to strengthen original synchronous hypothesis, to reduce contingent false alarm probability.Usually we call single to the catching method that does not have verifying logic and stay method, and the catching method that one or more verifying logics are arranged is called the method for repeatedly staying.The single method of staying can adopt the complete period to be correlated with or the partial periodicity correlation technique detects, and this is relevant with concrete frequency expansion sequence length and system complexity.Repeatedly stay method almost without any exception in detecting for the first time shorter partial periodicity of employing time relevant, to accelerate acquisition procedure, because the relevant high shortcoming of false alarm probability of partial periodicity can be improved by verifying logic.
Another one importance in the frequency expansion sequence grabber is exactly the search strategy to the unknown phase interval, i.e. the process in all unknown phase intervals between the specific search sending and receiving frequency expansion sequence of detector employing.This traversal search process can be continuous or discrete.Usually we are divided into limited junior unit to all unknown phase intervals, detect a unit at every turn.Search plan can be serial successively, also can be parallel, perhaps and go here and there combination, perhaps from certain specific zone, expands to whole zone gradually.
Existing frequency expansion sequence catching method mainly adopts the active correlation intergal catching method or the matching wave filter capture method of serial search, parallel search, memory parallel search and hybrid parallel search fully.Serial search correlation intergal catching method is that the frequency expansion sequence that receives is carried out one by one phase search, and till frequency expansion sequence phase place that receives and local frequency expansion sequence Phase synchronization, though the method is simple, capture time is but very long.Fully parallel search correlation intergal catching method and matching wave filter capture method are maximum quick capturing methods of usefulness up to now, and their capture time is short, but realizes circuit complexity (needed hardware resource is many).Memory parallel search correlation intergal and hybrid parallel search correlation intergal catching method also are the methods of catching fast, they combine the advantage of serial search correlation intergal and complete parallel search correlation intergal catching method, made a balance and select between hardware resource and systematic function.Above-mentioned several catching method has plenty of to be realized simply, but capture time is long.It is short to have plenty of capture time, need expend a large amount of hardware resources but implement.
Purpose of the present invention is exactly at above-mentioned the deficiencies in the prior art, reverse random access channel is caught fast in a kind of WCDMA of being applicable to communication system new method and device are proposed, and the additional result analysis, can reach and can either save hardware resource, can realize the purpose of catching fast again.
In the WCDMA communication system, the channel architecture of reverse random access channel as shown in Figure 1.Among the figure, prefix part is produced after through the scrambler spread spectrum by prefix signature, and the prefix signature is to be to obtain after the long Kazakhstan moral sign indicating number sequence of 16 chips repeats 256 times by length, and the total length of prefix signature just is that 4096 chips are long, and prefix is signed and always had 16.Prefix part adopts Quadrature Phase Shift Keying (QPSK) band spectrum modulation.Have only 4096 chips long because prefix inserts the length of part, receiving terminal must will utilize the long prefix of 4096 chips at an access slot, and promptly 5120 chip lengths search correct phase point in the time.
(3) summary of the invention:
Method of the present invention realizes by following scheme: the prefix signature according to Random Access Channel is the characteristic that is obtained for 256 times by the long Kazakhstan moral sign indicating number sequence extension of 16 chips, after the baseband signal that receives is passed through I, the demodulation of Q scrambler respectively, carry out the long quick Kazakhstan moral code conversion (FHT) of 16 chips respectively, can obtain 16 correlated results simultaneously the prefix signature.With the result of conversion through 256 times add up (being equivalent to total correlation length is 1024 chips), square and after I, the addition of Q two-way correlated results handle, getting maximum from 16 compares with the double threshold of being with proof scheme, when testing result is all bigger than given thresholding, illustrate that grabber has captured correct phase point and correct prefix signature.
The inventive method step can be described below:
1. the data that receive at first are buffered in the data register, read the long data of 16 chips at every turn and give the scrambler demodulation.
2. the I road and the Q roadbed band signal data that receive are removed scrambler processing (scrambler demodulation), exactly with local spectrum-spreading code generator scrambler that produces and the relevant treatment that receives 4096 chip lengths of signal work.
3. scrambler demodulated I, Q two paths of data are carried out 16 long quick Kazakhstan moral code conversions (FHT) respectively, breathe out the relevant of moral sign indicating number sequence with quick realization.I behind the FHT, Q two-way result are carried out respectively square, and last, the results added with after I, Q two-way square obtains detecting court verdict.The concrete operations of 16 long Kazakhstan moral code conversions as shown in Figure 2.Among the figure 1,2 ... 16 expression length are the 1st of 16 Kazakhstan moral sign indicating number sequence, the 2nd ... the 16th.
4. the court verdict that obtains after the incoherent detection carries out maximum and chooses, and this is because length is the quick Kazakhstan moral code conversion of 16 chips, and just in time corresponding 16 correlations of input signal with 16 prefix signatures need therefrom select of maximum.
5. be the false alarm probability that reduces grabber, thereby shorten capture time, the dual-threshold judgement method that the present invention has adopted the band back to verify.Being about to the court verdict that step 4 obtains at first compares with threshold value 1, do like this that can to exclude be not correct phase point obviously, if court verdict greater than threshold value 1, then compares this value again with threshold value 2, like this, can obtain higher detection probability and lower false alarm probability.Grabber is adjudicated the whether setting of the required threshold value of acquisition success and is adopted Newman-Pearson (Neyman-Pearson) criterion.
6. if the court verdict of detector output is greater than threshold value, system enters tracking mode, otherwise grabber changes the phase state of local scrambling generator, and repeating step 1-6 is to proceed detection to next unknown phase state.
Apparatus of the present invention comprise data register, scrambler demodulator, breathe out moral code converter (FHT), accumulator, squarer, adder, maximum-value selector, comparator 1 and comparator 2, validator and phase search controller.
It is characterized in that adopting the dual-threshold judgement of band back checking, i.e. the output of maximum-value selector is connected with comparator 1 earlier, is connected with comparator 2 by validator again.
The invention provides in the WCDMA system quick capturing method and device based on the reverse random access channel of quick Kazakhstan moral code conversion, it has effectively utilized the characteristics of reverse random access channel among the WCDMA, by adopting the moral code conversion of quick Kazakhstan to replace traditional active correlation intergal device, can shorten the correlation intergal time greatly, realize catching fast; Simultaneously, adopt and breathe out the traditional correlation intergal device of moral code conversion replacement, can also save the needed hardware resources of acquisition equipment in a large number.The needed hardware resource of the inventive method and existing catching method is compared as follows:
We suppose that the unknown phase state range that grabber need be searched for is 200 chips, if search precision is 1/2 chip, then having 400 unknown phase points needs search.
If adopt the catching method of existing serial phase search correlation intergal, can not satisfy the WCDMA system to of the requirement (seeing accompanying drawing 4) of mean acquisition time needs less than 5120 chip lengths times.
If adopt the quick capturing method of parallel fully phase search correlation intergal, then, need 400*16*2=12800 parallel correlator for 400 unknown phase points.
If adopt the quick capturing method of traditional hybrid parallel phase search correlation intergal, suppose that correlation length gets 1024 chips, the prefix part of 4096 chip lengths can be divided into 4 serial related intervals altogether so.The search of 400/4=100 unknown phase point must be finished in each interval.Simultaneously, because 16 prefixes signature is arranged, and I, Q two-way walk abreast, so the number of the parallel correlator that needs is 100*16*2=3200 altogether.
If use matched filter to realize, need there be two groups of 16 different matched filters to realize matched filterings simultaneously to I, Q two paths of data signal and 16 prefix signatures to the catching of reverse random access channel among the WCDMA.And in fact digital matched filter is exactly a multistage parallel accumulator, and the number of accumulator is corresponding with the correlation length of detector, long if correlation length is got 1024 chips, and a matched filter just needs 1023 accumulators to realize so.Just need 1023*2*16 accumulator altogether.
Beneficial effect of the present invention: adopt the inventive method, breathe out moral code conversion realization to breathing out the related operation of moral sign indicating number sequence, not only save correlation time, can also finish being correlated with simultaneously to 16 prefix signatures with quick.Because the Kazakhstan moral sign indicating number sequence of reverse random access channel prefix is that 16 chips are long among the WCDMA, like this, only need 4 grades of conversion just can finish the relevant of the long Kazakhstan moral sign indicating number sequence of 16 chips.Because every grade of conversion needs 8 accumulators, then whole conversion only needs 32 accumulators just passable.To 16 available signatures and two branch roads of I, Q, need 32*16*2=1024 accumulator and 2 Kazakhstan moral transcoders (corresponding to I, Q two-way) just passable altogether, to compare with above-mentioned quick capturing method, required hardware resource has reduced greatly.
(4) description of drawings:
Fig. 1 is the channel architecture of uplink random access channel in the WCDMA system;
Fig. 2 is for to catch theory diagram fast based on the reverse random access channel of quick Kazakhstan moral code conversion;
Fig. 3 is for to catch the realization block diagram fast based on the reverse random access channel of quick Kazakhstan moral code conversion;
Fig. 4 is the detection probability performance map;
Fig. 5 is the false alarm probability performance map;
Fig. 6 is mean acquisition time figure;
(5) preferred forms:
Further specify the present invention below in conjunction with drawings and Examples.
Fig. 3 is the realization block diagram of WCDMA reverse random access channel quick capturing method of the present invention and device.
Apparatus of the present invention comprise with lower module: module 101,103 is respectively I, Q two paths of data register.The data that receive at first are buffered in the data register, read the long data of 16 chips at every turn, give the scrambler demodulation module, and promptly the scrambler demodulator 102,104.The I road and the Q roadbed band signal data that receive are carried out the scrambler demodulation; Module 105 and 106 is respectively I road and the Q road scrambling generator that is used for the scrambler demodulation.Module 107 and 108 is used for scrambler demodulated I, Q two paths of data, carrying out length respectively is the quick Kazakhstan moral code conversion (FHT) of 16 chips, the FHT module is exactly to replace traditional correlator with breathing out the moral code conversion, realization is to breathing out the relevant of moral sign indicating number sequence, compare with traditional correlation technique, adopt and breathe out the moral code conversion fast, can not only shorten correlation time, and can also obtain the correlation (corresponding 16 prefixes signature) of all 16 Hadamard sequences simultaneously.
Module 109-124 is that accumulator is that 16 I circuit-switched data (respectively corresponding 16 prefixes signature) behind the FHT is carried out respectively adding up for 256 times, and 125-140 module (accumulator) is to 16 Q circuit-switched data (corresponding respectively 16 prefixes signature) behind the FHT carry out respectively adding up for 256 times (in order to obtain and the corresponding spread processing gain of accumulation length); The module that I after adding up, Q two paths of data (16 prefixes signatures are arranged respectively) are carried out square is 141-172 (squarer); To square after I, Q two paths of data (16 prefixes signatures the are arranged respectively) module of carrying out addition be 173-188 (adder); Arrive this, WCDMA reverse random access channel of the present invention is caught fast and is adorned the incoherent detection that has realized I, Q two paths of signals, has obtained 16 court verdicts (corresponding 16 prefixes signature); Module 189 (maximum-value selector) is used for 16 statistical decision results are selected, and selects maximum; This value is compared in comparator 1 module 190 with thresholding 1 earlier, if greater than thresholding 1, testing result is just delivered to authentication module 191 (validator), compare in comparator module 192 with thresholding 2 again, if greater than thresholding 2, then correct phase point and the employed prefix signature of current mobile station have been caught in explanation, and system just enters tracking mode.Otherwise acquisition equipment continues the next unknown phase point of search under phase search controller module 193 (phase search controller) control.
The hardware resource of the inventive method and above-mentioned other several quick capturing methods more as mentioned above, their performances under the same conditions are more respectively as Fig. 4, shown in 5,6.
Claims (6)
1. the quick capturing method of a reverse random access channel, it is characterized in that: the prefix signature according to Random Access Channel is the characteristic that is obtained for 256 times by the long Kazakhstan moral sign indicating number sequence extension of 16 chips, the baseband signal that receives is being passed through I respectively, after the demodulation of Q scrambler, carry out the long quick Kazakhstan moral code conversion (FHT) of 16 chips respectively, can obtain 16 correlated results simultaneously to the prefix signature, with the result of conversion through 256 times add up (being equivalent to total correlation length is 1024 chips), square and I, after the addition of Q two-way correlated results is handled, getting maximum from 16 compares with the double threshold of being with proof scheme, when testing result is all bigger than given thresholding, illustrate that grabber has captured correct phase point and correct prefix signature.
2. require the quick capturing method of described a kind of reverse random access channel as right 1, it is characterized in that: the frequency expansion sequence of Random Access Channel is to be obtained for 256 times by 16 long Kazakhstan moral sign indicating number sequence extension.
3. require the quick capturing method of described a kind of reverse random access channel as right 1, it is characterized in that: use 16 long quick Kazakhstan moral code conversions (FHT) to ask the method for correlation to replace traditional relevant method that adds up with matched filtering.
4. require the quick capturing method of described a kind of reverse random access channel as right 1, it is characterized in that: relatively replace simple gate limit relatively with double threshold, obtain the purpose of short capture time, high detection probability with this.
5. the quick catching device of a reverse random access channel is characterized in that: this device comprises data register, scrambler demodulator, breathes out moral code converter (FHT), accumulator, squarer, adder, maximum-value selector, comparator 1 and comparator 2, validator and phase search controller.
6. require the quick catching device of described a kind of reverse random access channel as right 1, it is characterized in that: adopt the dual-threshold judgement of band back checking, i.e. the output of maximum-value selector is connected with comparator 1 earlier, is connected with comparator 2 by validator again.
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008049321A1 (en) * | 2006-10-20 | 2008-05-02 | Huawei Technologies Co., Ltd. | Method for initiating and detecting reserve access and device thereof |
| CN100387096C (en) * | 2004-12-23 | 2008-05-07 | 华为技术有限公司 | Method for determining capture threshold of random access channel through physical layer |
| CN100393168C (en) * | 2004-08-04 | 2008-06-04 | 中兴通讯股份有限公司 | CDMA system random access threshold multi-path selection method |
| WO2009092298A1 (en) * | 2008-01-09 | 2009-07-30 | Huawei Technologies Co., Ltd. | Channel searching device, method and system |
| CN101128004B (en) * | 2006-08-18 | 2010-10-27 | 华为技术有限公司 | Detection method, terminal and network device for random access |
| WO2010148809A1 (en) * | 2009-12-21 | 2010-12-29 | 中兴通讯股份有限公司 | Mehod and system for recognizing random access burst signal |
| CN111565161A (en) * | 2020-04-28 | 2020-08-21 | 北京升哲科技有限公司 | Baseband transmitter, baseband receiver, modulation and demodulation system and terminal |
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2002
- 2002-03-27 CN CNB021165033A patent/CN1163008C/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100393168C (en) * | 2004-08-04 | 2008-06-04 | 中兴通讯股份有限公司 | CDMA system random access threshold multi-path selection method |
| CN100387096C (en) * | 2004-12-23 | 2008-05-07 | 华为技术有限公司 | Method for determining capture threshold of random access channel through physical layer |
| CN101128004B (en) * | 2006-08-18 | 2010-10-27 | 华为技术有限公司 | Detection method, terminal and network device for random access |
| WO2008049321A1 (en) * | 2006-10-20 | 2008-05-02 | Huawei Technologies Co., Ltd. | Method for initiating and detecting reserve access and device thereof |
| CN101166362B (en) * | 2006-10-20 | 2011-03-16 | 华为技术有限公司 | Method and equipment for originating and detecting reverse access |
| WO2009092298A1 (en) * | 2008-01-09 | 2009-07-30 | Huawei Technologies Co., Ltd. | Channel searching device, method and system |
| CN101217817B (en) * | 2008-01-09 | 2010-09-15 | 华为技术有限公司 | Channel searching device, method and system |
| WO2010148809A1 (en) * | 2009-12-21 | 2010-12-29 | 中兴通讯股份有限公司 | Mehod and system for recognizing random access burst signal |
| RU2515227C2 (en) * | 2009-12-21 | 2014-05-10 | Зти Корпорейшн | Method and system for determining packet message signal |
| CN111565161A (en) * | 2020-04-28 | 2020-08-21 | 北京升哲科技有限公司 | Baseband transmitter, baseband receiver, modulation and demodulation system and terminal |
| WO2021217896A1 (en) * | 2020-04-28 | 2021-11-04 | 北京升哲科技有限公司 | Baseband transmitter, baseband receiver, modulation and demodulation system, and terminal |
| CN111565161B (en) * | 2020-04-28 | 2022-05-27 | 北京升哲科技有限公司 | Baseband transmitter, baseband receiver, modulation and demodulation system and terminal |
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