CN1604662A - Method and equipment for detecting middle guiding code sequence in TD-SCDMA system - Google Patents

Abstract

It is a kind of Midamble code sequence detection method and apparatus for TD-SCDMA mobile communication system. It can reach high detection probability and low missing probability under the condition of low signal-to-noise ratio and the under the environment of having frequency diffusion and time diffusion. It can also generate rejection mark and exclude a batch of wrong input incident, such as wrong code set sequence number input, wrong synchronous Information input and local oscillator has large frequency deviation, so to realize the reduction of initializing community research time in TD-SCDMA system. This invention includes the module and steps such as Midamble receives signal sample extraction, Midamble code sequence generation, slide association, delay envelope calculation, multi-frame combination, path selection, similar value calculation, maximum value detection, confidence level calculation and compare, the generation of detection rejection mark, and generation of detection Midamble code sequence number.

Description

Detect the method and apparatus of middle guiding code sequence in the TDS-CDMA system

Technical field

The present invention relates to a kind of wireless communication system of being applied to, be particularly related to a kind of TD SDMA (Time Division Synchronous Code-Division Multiple Access that is applied to, abbreviation TD-SCDMA) in the mobile communication system, the method and apparatus of in search of initial zone (Initial Cell Search) process, leading sign indicating number (Midamble) sequence in the detection of subscriber terminal equipment.

Background technology

Nineteen forty-six, the Bell Laboratory of the U.S. has just proposed the service area of mobile phone is divided into several sub-districts, and a base station is established in each sub-district, constitutes honeycomb (Cellular) the mobile communication new ideas of cellular communication system.1978, this system succeedd in the Chicago,U.S test, and formally puts it into commercial operation in nineteen eighty-three.The employing of cellular system makes identical frequency to reuse, thereby has increased the capacity of mobile communication system greatly, has adapted to the desirability that mobile communication subscriber increases suddenly.The development of cell mobile communication systems experienced one from the simulation net to digital network, from frequency division multiple access (FDMA) to time-division multiple access (TDMA) with the process of code division multiple access (CDMA).

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, and wherein CDMA occupies an leading position.In CDMA technology, International Telecommunications Union has accepted 3 kinds of standards at present altogether, i.e. the TD-SCDMA standard of the CDMA 2000 of the W-CDMA 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, TDD), smart antenna (Smart Antenna), joint-detection technology such as (JointDetection), the availability of frequency spectrum is very high, 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.

As shown in Figure 1, be the example of a typical cell mobile communication systems.This system is by a plurality of sub-districts 10 ₁-10 _N(10) constitute, a base station (Base Station) 11 is wherein respectively arranged in each sub-district ₁-11 _N(11), the subscriber terminal equipment (UserEquipment) 12 that in this sub-district service range, has some simultaneously ₁-12 _N(12).Each subscriber terminal equipment 12 by with affiliated Serving cell 10 in base station 11 keep being connected, finish and other communication equipment between communication function.

Each after subscriber terminal equipment 12 starts, general and do not know its residing position and should select which base station 11 (perhaps the sub-district 10) to carry out relevant up access (Uplink Access) and operate.The process that subscriber terminal equipment selects the sub-district to insert is commonly referred to as " search of initial zone " (InitialCell Search) process.The purpose that subscriber terminal equipment 12 carries out search of initial zone is to select suitable working frequency points, and on this frequency, obtain with certain sub-district 10 in the down-going synchronous of base station 11, understand the relevant system broadcast message that this base station 11 sends simultaneously---according to these information, subscriber terminal equipment 12 could begin relevant up access procedure, and final set up with this base station 11 between be connected.

As shown in Figure 2, be the frame structure schematic diagram of TD-SCDMA system.This structure is according to low spreading rate (LCR) tdd mode (1.28Mcps) among 3G collaborative project (3GPP) the standard TS 25.221 (Release 4), perhaps provides among China Wireless Telecommunication Standar (CWTS) the standard TSM 05.02 (Release 3).The spreading rate of TD-SCDMA system is 1.28Mcps, each radio frames (RadioFrame) 20 ₀, 20 ₁(20) length is 5ms, i.e. 6400 chips (for 3GPP LCR-TDD system, each radio frames length is 10ms, and the subframe (subframe) that can be divided into two length be 5ms, and wherein each subframe comprises 6400 chips).Wherein, the radio frames in each TD-SCDMA system (the perhaps subframe in the LCR system) 20 can be divided into 7 time slots again (TS0～TS6) 21 ₀-21 ₆(51), and two pilot time slots: descending pilot frequency time slot (DwPTS) 22 and uplink pilot time slot (UpPTS) 24, and protection (Guard) 23 at interval.Further, the TS0 time slot 21 ₀Be used to bearing system broadcast channel and other possible downlink traffic channel; And TS1～TS6 time slot 21 ₁-21 ₆Then be used to carry the uplink and downlink Traffic Channel.It is synchronous that UpPTS time slot 24 and DwPTS time slot 22 are used to set up initial uplink and downlink respectively.TS0～TS6 time slot 21 ₀-21 ₆Length is 0.675ms or 864 chips, wherein comprises data segment DATA1 (27) and DATA2 (29) 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 28.The Midamble sequence is significant at TD-SCDMA, comprise cell ID, channel estimating and synchronously modules such as (comprising Frequency Synchronization) all to use it.DwPTS time slot 22 comprise one long be descending synchronous code (SYNC-DL) code word 25 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 26 of 128 chips, subscriber terminal equipment utilizes it to carry out relevant up access procedure.

According to the relevant definition among 3GPP standard TS 25.224 (Release 4) or the CWTS standard TSM 05.08 (Release3), in the TD-SCDMA system, after finishing initial frequency selection, on each candidate's frequency, initial cell search procedure can be divided into following four steps:

First step, DwPTS search: by with after 32 SYNC-DL code words 25 are carried out relevant treatment or similar processing with the received signal sequence altogether, obtain (roughly) synchronizing information of DwPTS time slot, detect most possible SYNC-DL code word simultaneously;

Second step, scrambler and Midamble codeword sequence detect: after obtaining the DwPTS coarse position information, can receive according to TD-SCDMA frame structure user terminal and to be positioned at TS0 (21 ₀) go up the Midamble part received signal 28 on the P-CCPCH channel.Because each SYNC-DL code word 25 corresponding code character (CodeGroup), 4 possible Midamble codeword sequences have been comprised, therefore by after the received signal of these 4 possible code words and the last Midamble part of TS0 is carried out relevant treatment or similar processing, can the system of detecting adopt wherein which Midamble codeword sequence; Because there are one-to-one relationship in scrambler (Scrambling Code) and Midamble code word, so scrambler obtains after also can detecting the Midamble codeword sequence simultaneously;

Third step, the control multi-frame is synchronous: in the TD-SCDMA system by SYNC-DL sign indicating number 25 being carried out QPSK (quarternary phase-shift keying (QPSK)) modulation and determining to control the beginning of multi-frame (Control Multi-frame) according to the phase modulation pattern on the SYNC-DL code word 25 in continuous four frames.User terminal is by determining that to the detection that receives modulation phase pattern on the SYNC-DL character signal control multi-frame is synchronous;

The 4th step, read BCCH information: after acquisition control multi-frame was synchronous, just can know had BCCH (broadcast channel) system broadcast message to exist on which frame; User terminal carries out demodulation (Demodulation) and decoding (Decoding) to the reception data on the P-CCPCH (Primary Common Control Physical Channel) of these frames, carries out Cyclic Redundancy Check then; If verification is passed through, then this piece BCCH information is considered to effectively and is delivered to high level, and the initial cell process successfully finishes.

Wherein, in described Cell searching second step, the detection performance of Midamble codeword sequence comprises the search probability of success and search time etc. for the performance of whole search of initial zone, all important influence.When designing the detection method of Midamble codeword sequence in described second step, should consider following requirement:

(1) correct detection probability (Correct DetectionProbability) that requires the Midamble codeword sequence near the target working point enough high (for example, be higher than 95%) so that follow-uply can utilize this Midamble codeword sequence to carry out operate as normal about module (comprising channel estimating, route searching/tracking, automatic frequency control AFC and Cell searching third step module etc.) as training sequence;

(2) require the probability probability of false detection (False Detection Probability) enough low (for example, being lower than 1%) of (when input information is correct) Midamble codeword sequence error detection again.Because detecting output, wrong Midamble codeword sequence will cause follow-up relevant module cisco unity malfunction, and generally these modules (for example often need the process long period, through behind the dozens or even hundreds of frame) could find that its input Midamble codeword sequence is wrong, and then return search of initial zone second step or before step carry out the detection of Midamble codeword sequence again---and this will prolong the time of search of initial zone greatly, and may not satisfy the maximum constraints of system to this search time;

(3) in addition, for some wrong input conditions, it is excessive to comprise that described cell search first step is exported SYNC-DL mistake, DwPTS coarse synchronization mistake or local oscillator (Local Oscillator) frequency shift suddenly, and situation such as automatic gain control (AGC) is unusual, preferably require described Cell searching second step can in time find these situations, and step re-execute relevant operation before returning.For example, at International Patent Application Publication No. WO03/028399, denomination of invention is among " small region search method and communication terminal device " (CELL SEARCH METHOD AND COMMUNICATION TERMINAL APPARATUS), a kind of rapid method and apparatus of described cell search first step of carrying out in the TD-SCDMA system is mainly disclosed, it is relevant at first each SYNC-DL sign indicating number and received signal to be slided in this method, and finds the SYNC-DL of correlation maximum and correspondence position thereof as output.Notice in this method, in order to improve successful detection probability as much as possible, do not adopt any maximum related value and threshold value are made comparisons after the method for output again, and always export a SYNC-DL testing result.Like this, when communication environment more abominable, for example (Signal to Interference plus Noise Ratio SINR) is worth when hanging down the synchronizing information of the SYNC-DL testing result of the suddenly possible output error of described cell search first step and/or mistake to Signal Interference and Noise Ratio.In this case, if described Cell searching second step can not will should be got rid of in the mistake input, offer the subsequent module use but continue to produce (mistake) Midamble codeword sequence testing result, will with above-mentioned (2) in analyzed like that cause the lengthening greatly of search of initial zone time because mistake spreads;

(4) require still can keep preferable performance under should be in the various mobile communication system common abominable communication environments of designed Midamble codeword sequence detection method.Multipath fading be frequency diffusion (Frequency Dispersive) phenomenon to ubiquity in the mobile communication propagation channel, can cause the SINR value of received signal bigger fluctuating can occur within a short period of time.On the other hand,, can life period spread (Time Dispersive) phenomenon again simultaneously, promptly produce serious intersymbol interference (Inter-Symbol Interference, ISI) problem for CDMA broadband communication systems such as (code division multiple accesss).A good detection algorithm should performance in these cases should not have big deterioration;

(5) owing to be operated in the search of initial zone stage, many synchronizing processes, for example time synchronized and Frequency Synchronization etc., often accurately do not finish as yet, so require Midamble codeword sequence detection method that certain robustness (Robustness) should be arranged, overcome the detection mis-behave problem that above-mentioned non-accurate stationary problem may cause.

Existing Midamble codeword sequence detection method at search of initial zone second step design of TD-SCDMA system, often only considered the part requirement in above-mentioned five designing requirements, for example require (1), this will cause detection algorithm other parts reduction of property indexes (for example probability of false detection is too high), perhaps cause it to produce serious mis-behave in some cases.For example, at International Patent Application Publication No. WO03/032512, denomination of invention is in " capture circuit of low spreading rate mode mobile communication system " (ACQUISITION CIRCUIT FOR LOW CHIP RATE OPTION FOR MOBILETELECOMMUNICATION SYSTEM), discloses a kind of circuit arrangement that carries out search of initial zone in the TD-SCDMA system.But in the wherein relevant device of Cell searching second step, just the output of the Midamble codeword sequence of correlation maximum, so fail the fine previous designs requirement (2) and (3) of satisfying; Simultaneously, since receive Midamble signal section position according to cell search first step rapid in detected DwPTS position directly provide, owing to do not consider because time synchronized inaccuracy that may exist and the influence of multipath fading fast, so this device also fails finely to satisfy previous designs and require (4) and (5).

Summary of the invention

The object of the present invention is to provide a kind of method and apparatus that is applied to the detection middle guiding code sequence of subscriber terminal equipment in TD SDMA (TD-SCDMA) mobile communication system, it can and exist in the mobile communication environment of frequency diffusion and time diffusion under low signal-to-noise ratio (SINR) condition, reaches to have higher correct detection probability; Has very low probability of false detection; And can be with a series of wrong incoming events of higher probability debug.

The present invention at first provides the detection method of leading sign indicating number in a kind of TD-SCDMA of being applied to system customer equipment receiver, and this method may further comprise the steps:

In lead sign indicating number (Midamble) codeword sequence received signal sampling extraction step, according to the relevant timing information that provides suddenly by initial cell search first step, according to certain sample mode, lead near part and the received signal of yard codeword sequence in extracting in the present frame, obtain a sample sequence r;

In lead sign indicating number (Midamble) codeword sequence and generate a step, according to by the determined code character of the rapid detected down-going synchronous of initial cell search first step (SYNC-DL) sign indicating number, for leading sign indicating number (Midamble) codeword sequence among each candidate in this code character, generate a sequence s respectively;

The slip correlation step, lead in will receiving sign indicating number (Midamble) signal sample sequence r respectively with each candidate in lead sign indicating number (Midamble) codeword sequence s slide by certain mode relevant after, obtain the output sequence C that is correlated with;

Time delay envelope calculation procedure is calculated respectively corresponding to the time delay envelope D that leads sign indicating number (Midamble) codeword sequence among each candidate according to relevant output sequence C;

The multiframe combining step, with each envelope D respectively with preceding frame in obtain, merge by certain merging mode corresponding to the time delay envelope D that leads sign indicating number (Midamble) codeword sequence in the same candidate, and preserve amalgamation result; After the merging of F frame,, obtain a time delay envelope DP corresponding to leading sign indicating number (Midamble) codeword sequence among each candidate;

The Path selection step, after merging according to multiframe, lead the time delay envelope DP of sign indicating number (Midamble) codeword sequence in corresponding each candidate, carry out Path selection by certain routing criterion, obtain set of paths S;

The likelihood value calculation procedure is led sign indicating number (Midamble) codeword sequence in corresponding each candidate, respectively the value that is positioned on the selected path S among the time delay envelope DP is merged, and obtains corresponding " likelihood value " H;

Maximum detects step, finds out in the candidate of " likelihood value " H maximum and leads sign indicating number (Midamble) codeword sequence, and its sequence number is M;

The confidence level calculation procedure according to leading " likelihood value " of leading sign indicating number (Midamble) codeword sequence in sign indicating number (Midamble) codeword sequence and other all candidates in the maximum likelihood value, calculates " confidence level " R of maximum likelihood value Midamble codeword sequence;

Comparison step compares " confidence level " R and a default thresholding T;

Detect refusal sign output step,, the value that output detects " refusal " sign is set according to the comparative result of comparison step;

Midamble codeword sequence sequence number output step, when output detection " refusal " is masked as " vacation " (when accepting testing result), the sequence number M of output maximum likelihood value Midamble codeword sequence;

Further, the invention provides the checkout gear of the Midamble codeword sequence in a kind of TD-SCDMA of being applied to system receiver, described device comprises:

Midamble received signal sampling extractor according to the relative synchronous information that is provided suddenly by initial cell search first step, extracts Midamble part and near received signal thereof in the present frame by certain mode, obtains a sample sequence;

Midamble codeword sequence maker according to by the determined code character of the rapid detected SYNC-DL sign indicating number of initial cell search first step, for each candidate Midamble codeword sequence in this code character, generates a sequence respectively;

Sliding correlation detector, will receive the Midamble signal sample sequence respectively with each candidate Midamble codeword sequence slide by certain mode relevant after, obtain relevant output sequence;

Time delay envelope calculator calculates time delay envelope corresponding to each candidate Midamble codeword sequence respectively according to relevant output sequence;

Multiframe combiner, with each envelope respectively with frame before in obtain, merge by certain mode corresponding to the time delay envelope of same candidate Midamble codeword sequence, and preserve amalgamation result; After some frames merging,, obtain a time delay envelope corresponding to each candidate Midamble codeword sequence;

Path selector is used for carrying out Path selection according to time delay envelope after the multiframe merging, corresponding each candidate Midamble codeword sequence by certain criterion;

The likelihood value calculator is used for corresponding each candidate Midamble codeword sequence, respectively the value on the selected path in the time delay envelope is merged, and obtains corresponding " likelihood value ";

Maximum value detector is used to find out " likelihood value " maximum candidate Midamble codeword sequence;

The confidence level calculator is used for " likelihood value " according to maximum likelihood value Midamble codeword sequence and other all candidate Midamble codeword sequences, calculates " confidence level " of maximum likelihood value Midamble codeword sequence;

Comparator is used for " confidence level " result of calculation and a default thresholding are compared, and according to comparative result the value that output detects " refusal " sign is set;

The method and apparatus of the detection Midamble codeword sequence of realizing according to the present invention that is used for TD-SCDMA system subscriber terminal equipment, can and exist in the mobile communication environment of frequency diffusion and time diffusion under low SINR condition, reach higher correct detection probability and very low probability of false detection.Simultaneously, this method and apparatus can also produce the incoming event that the refusal sign is got rid of a collection of mistake, situations such as for example wrong code character sequence number input, the synchronizing information input of mistake and local oscillator frequency deviation are excessive, thus reach the purpose that shortens the search of initial zone time in the TD-SCDMA system effectively.

The description of the method and apparatus that objects and advantages of the present invention detect by Midamble codeword sequence in search of initial zone second step in the following TD-SCDMA system, it is more and more obvious to become.

Description of drawings

Fig. 1 is the rough schematic of a typical cell mobile communication systems;

Fig. 2 is the frame structure schematic diagram of TD-SCDMA system;

Fig. 3 is the schematic flow sheet of the detection method according to the present invention;

Fig. 4-1,4-2,4-3 are for realizing the slide structured flowchart of 3 kinds of devices of correlation step of the present invention;

Fig. 5-1,5-2,5-3 are the schematic diagram of realizing 3 kinds of methods of Path selection step of the present invention;

Fig. 6 is the circuit theory diagrams of the checkout gear according to the present invention;

Fig. 7 is the flow chart that applies the present invention to a kind of method in the TD-SCDMA system initial cell search procedure; And

Fig. 8 is the schematic diagram that applies the present invention to the another kind of pipeline organization method in the TD-SCDMA system initial cell search procedure.

Embodiment

Following according to Fig. 3, Fig. 4-1,4-2,4-3, Fig. 5-1,5-2,5-3, and Fig. 6～Fig. 8 illustrate better embodiment of the present invention.

As shown in Figure 3, be the schematic flow sheet of detection method of the present invention.At first, subscriber terminal equipment obtains corresponding code character according to the rapid detected descending synchronous code of initial cell search first step (SYNC-DL sign indicating number), and generates 4 candidate Midamble codeword sequence s (step 300) in this code character; Then, frame count is changed to 1 (step 301); Then, as step 302, the relative synchronous information that provides during subscriber terminal equipment is will be according to initial cell search first step rapid, receive " search window " interior Midamble codeword sequence, with and near the sampled value of data, obtain sample sequence r.Wherein, in order to overcome the mis-behave that is caused owing to the sampling time deviation, the sampling rate of sampler should be higher than the spreading rate (Chip Rate) of system here, promptly adopts over-sampling (Oversampling) method.Here recommendation employing multiple is 2 over-sampling speed, and promptly corresponding each chip obtains two sampled values.Although adopt higher over-sampling speed meeting (limited) further to improve performance, also high many of its corresponding Digital Signal Processing complexity.On the other hand, according to the rapid given DwPTS position of initial cell search first step, and the frame structure of TD-SCDMA system (as shown in Figure 2), subscriber terminal equipment can be derived the residing position of Midamble codeword sequence on the TS0 time slot, and receives data sampling that should section Midamble codeword sequence.Simultaneously, for following consideration, subscriber terminal equipment may also need to receive the interior data sampling of some chips of Midamble signal section front and back, because:

(1) the DwPTS position synchronous information that provides of first step may be very inaccurate, might have the synchronism deviation in several chip range; Need set up one so-called " search window " this moment near the SYNC-DL synchronous points, solve the synchronism deviation problem that may exist;

(2) for quick multidiameter fading channel, the Strength Changes in each bar footpath is very fast, has a kind of possibility to be, has weakened in previous detected that (the strongest) path of first step, and have other new strong footpath to occur nearby; At this moment, also need to set up one " search window ", catch near those strong footpaths that may occur the synchronous points, to guarantee good detection performance.

General, described " search window " should comprise L chip and R the sampled data that chip is interior afterwards before the Midamble signal section that length is 144 chips, comprises the interior data sampling of L+R+144 chip so altogether.The oversampler method of corresponding 2 times of speed will receive 2 * (L+R+144) individual data samplings altogether.Wherein, parameter L and R are and are greater than or equal to zero integer, and their value is by the decision of factors such as system design and actual working environment, and the recommendation value is L=R=16.Wherein, Midamble signal section position described here is the original position P by the rapid resulting DwPTS part of initial cell search first step _DwPTSDerived.According to the frame structure of TD-SCDMA system, the original position P of Midamble signal section _MidambleCan obtain as follows:

P _Midamble=P _DwPTS-352-16 (chip);

As a kind of alternative method, also can only extract the data sampling that receives in back 128 chips in the Midamble signal section that length is 144 chips (128 chips of a certain end perhaps) according to the cycle characteristics of the formation of Midamble codeword sequence in the TD-SCDMA system.Accordingly, in order to reach and aforementioned " search window " similar effect, the cycle characteristics that utilizes the Midamble codeword sequence to have, in slip correlation step as described later, need to adopt in the described slip correlation step in " circular correlation " (Periodic Correlation) back, need to adopt the method for " circular correlation " (Periodic Correlation).Compare with preceding a kind of method, this method need not receive the data sampling in the extra L+R chip, so that complexity is compared is low; But owing to only adopted 128 chip lengths relevant, so its performance is compared the loss of 10*log is arranged (144/128) ≈ 0.5dB with preceding a kind of method.

Subsequent, subscriber terminal equipment slides relevantly in described search window with all candidate Midamble codeword sequences Midamble signal data sample sequence respectively, and obtains a collection of related data result (step 303).Consider according to different applied environments and realization, can adopt different slip correlation techniques to realize this step here.With reference to figure 4-1 to 4-3, be depicted as the structured flowchart of 3 kinds of possible relevant devices that slide.At first, receive analog baseband signal, obtain the data sampling in corresponding training sequence signal section and front and back " search window " thereof by behind the over-sampling device 40.Then, these data samplings pass through a series of delayers 41 successively ₁-41 _2*N-2Corresponding to 2 times of fast sampling clocks, have 2 * (N-1) such delayers, their input clock and sampling clock are consistent.Wherein, at i constantly, from the input and the 2nd, 4 of first delayer of a left side ..., 2 * (N-1) output, constituted one and longly be the sequence r of N _i: { r _{I-2 (N-1)}, r _{I-2 (N-2)}..., r _i, the corresponding interior reception data sampling of a nearest N chip.On the other hand, producing another length by training sequence maker 43 is the codeword sequence s:{s of N ₁, s ₂..., s _N, its index (code word sequence number) is provided by system's high level or other module detects gained.This codeword sequence obtains another behind the device 44 and longly is the sequence s*:{s of N through gripping altogether ₁ ^*, s ₂ ^*..., s _N ^*.Then, received signal sequence r _iGrip codeword sequence s* together through an a collection of N complex multiplier 42 _1-NAfter pursuing element and multiplying each other, obtain one and longly be the output sequence y of N _i: { y _{I, 1}, y _{I, 2}..., y _{I, N}.According to selected correlation length, the value of parameter N is chosen as 144 or 128 here.

Above-mentioned correlated process is undertaken by " slip " mode: that is every a sampling clock, receiving sequence is slided one when sampling kind to the right at interval, the receiving sequence that this length that is equivalent to be used to be correlated with is N has been upgraded a data sampling in time, simultaneously a collection of N the related data (sequences y altogether of this correlator output _i).It should be noted that then described " slip " also undertaken by endless form if adopt the method for " circular correlation "; At this moment, can also adopt the fast Fourier transform (FFT) method to realize the slip correlated process of this endless form at frequency domain (Frequency Domain)---but this method needs a series of plural rotary manipulation, and hardware is realized complicated.So suggestion is here adopted and is finished described slip correlation step based on the correlation technique of time domain (Time Domain).

Several correlation technique based on time domain described below all is according to receiving sequence y _iAnd codeword sequence s generates a correlation C _i:

(A1) total correlation (Full Correlation) method (realizing) by installing 45:

Shown in Fig. 4-1, with sequences y _iIn all N element, by obtaining relevant output C after adder 46 additions _iCan be expressed as with formula:

$C_i=\underset{k=1}{\overset{N}{\mathrm{\Σ}}}{y}_{i,k};$

When there is bigger frequency departure in subscriber terminal equipment local oscillator and base station place oscillator, adopt said method will cause certain associated loss (Coherent Loss), this associated loss L can be expressed as with formula:

$L=\frac{\sin \left(\mathrm{\π\Δf}{T}_{c}N\right)}{N\×\sin \left(\mathrm{\π\Δf}{T}_c\right)}$

In the following formula, parameter N is a correlation length, and parameter Δ f is a frequency departure, T _cBe system's chip width.For Midamble codeword sequence situation in the TD-SCDMA system (be N=144 or N=128, spreading rate 1/T _c=1.28Mcps), only recommend (just to adopt said method promptly ± 2～4kHz) time less than ± 1～2ppm as frequency deviation f.When local oscillator original frequency deviation too high and can not satisfy this and require the time, if adopt our rule need before this method of realization, add a frequency coarse adjustment process, otherwise because the associated loss that frequency departure causes will make this total correlation method cause severe exacerbation.

(A2) part correlation (Partial Correlation) and square merging method (realizing) by installing 47:

Shown in Fig. 4-2, sequences y _iAt first be divided into N/P cross-talk sequence, wherein every cross-talk sequence length is P.This P cross-talk sequence is respectively by an a collection of N/P adder 48 then _1-N/PAfter the addition, obtain N/P part correlation output { p ₁, p ₂..., p _N/P.Said process can be used following formulate:

$p_k=\underset{j=1}{\overset{P}{\mathrm{\Σ}}}{y}_{i,(k-1)\×P+j},k=\mathrm{1,2},\·\·\·,N/P;$

Adopt this part correlation method, the influence that can bring Chinese People's Anti-Japanese Military and Political College's frequency departure effectively.Corresponding TD-SCDMA system, according to some different initial frequency deviation scopes, the sub-sequence length P value of recommendation is as follows: (1) initial frequency deviation is at ± 2.5ppm (promptly ± 5kHz): P≤72; (2) initial frequency deviation is at ± 5ppm (promptly ± 10kHz): P≤36; (3) initial frequency deviation is at ± 10ppm (promptly ± 20kHz): P≤16.

Then, these part correlation data obtain relevant output C by a square merging _iThis is by a collection of squarer 49 _1-N/P, and adder 50 realizes.This merging mode can be expressed as with formula:

$C_i=\underset{k=1}{\overset{N/P}{\mathrm{\Σ}}}{\left|p_k\right|}^2$

In the following formula, the mould Value Operations is asked in symbol " || " expression.Except square merging mode, also can adopt incoherent (Non-Coherent) merging methods such as mould value merging, reach similar effects.

(A3) part correlation and difference merge (Differential Combining) method (realizing by installing 51):

Shown in Fig. 4-3, at first the same with said method A2, by an a collection of N/P adder 52 _1-N/PObtain a collection of part correlation output { p ₁, p ₂..., p _N/P.Then, grip multiplier 53 altogether by a collection of N/P _1-(N/P-1)And an adder 54, obtain relevant output C in difference merging mode _iSaid process can be expressed as with formula:

$C_i=\underset{k=1}{\overset{N/P-1}{\mathrm{\Σ}}}(p_k^{*}\×p_{k+1});$

In the following formula, symbol " * " expression conjugate operation.Compare with square merging mode among the preceding method A2, increase although its difference merges the complexity of mode, it can obtain good slightly performance, simultaneously its relevant output C _iPhase value in comprised phase information, the words that are necessary can be used to carry out frequency departure and estimate.

By described slip correlation step 303, when list entries length was 2 * (L+R+144) individual samplings, it can produce totally 2 * (L+R+1) individual subsequence r by being shifted _iLike this, corresponding each candidate Midamble codeword sequence, process can obtain a collection of totally 2 * (L+R+1) individual relevant outputs respectively after sliding and being correlated with, and remembers that they are: C ^m: { C ₁ ^m, C ₂ ^m..., C _{2 * (L+R+1)} ^m, wherein subscript m represents the Midamble codeword sequence sequence number (m=1,2,3,4) in the code character.Similarly, when adopting method of cyclic correlation, only consider relative cyclic shift-L chip and+totally 2 * (L+R+1) individual subsequence r in the R chip _i, still can obtain a collection of totally 2 * (L+R+1) individual relevant outputs after being correlated with through sliding like this.

Then, as step 304, corresponding to each candidate Midamble codeword sequence, subscriber terminal equipment is according to slip correlated results output C ^m, calculate the length that is positioned at described search window accordingly respectively and be 2 * (L+R+1) time delay envelope (Delay Profile).If time delay envelope sequence D ^m: { D ₁ ^m, D ₂ ^m..., D _{2 * (L+R+1)} ^m, then described time delay envelope computational process can adopt one of following several method to obtain:

Method B1: square acquisition of the mould value by asking corresponding relevant output, and available following formulate:

$D_k^m={\left|C_k^m\right|}^2,$ For k=1,2 ..., 2 * (L+R+1), m=1,2,3,4;

Method B2: the mould value that also can get relevant output valve produces the time delay envelope, that is:

$D_k^m=\left|C_k^m\right|,$ For k=1,2 ..., 2 * (L+R+1), m=1,2,3,4;

Method B3: perhaps also can directly get relevant output valve as the time delay envelope, that is:

$D_k^m=C_k^m,$ For k=1,2 ..., 2 * (L+R+1), m=1,2,3,4;

Corresponding aforementioned slip correlation technique A1, can adopt above method B1 or method B2 to come the calculation delay envelope, because because influences such as frequency departure and Doppler (Doppler) frequency displacement, phase reference in the consecutive frame generally changes, so the method that can not adopt relevant (Coherent) to merge.And for aforementioned slip correlation technique A2, because output has been a mould value, so can adopt above-mentioned any method to come the calculation delay envelope.At last, for aforementioned slip correlation technique A3, owing to the phase reference variation issue that has overcome by difference merging mode in the adjacent frame, so can adopt said method B3 to come the calculation delay envelope.

Then, whether step 305 judgment frame is counted greater than 1: if not, then preserve the time delay envelope of present frame; If, then by step 306, each time delay envelope that present frame is produced respectively with frame before in obtain, merge corresponding to the time delay envelope of same candidate Midamble codeword sequence, and preserve amalgamation result.Described delay packet complexing also can adopt the method by the element addition to realize.

Then, shown in step 307, frame count is added 1, and in step 308 judgment frame counting whether greater than a parameter value F: if not, then get back to step 302, and in next frame, repeat the operation among the abovementioned steps 302-307; If, show and handle F the frame that be over, and finished altogether signal extraction in F the frame, relevant, the time delay envelope of sliding calculates and the multiframe merging process, and carries out the judgement of relevant Midamble codeword sequence with entering subsequent step.Time delay envelope sequence after the multiframe of note gained merges is DP ^m(m=1,2,3,4).Wherein, parameter value F is a positive integer, and representative is carried out relevant Midamble and detected used total data frame number, and the F value is big more, and it is just good more to detect performance, but its complexity and time delay have also increased.Therefore, parameter F should and realize according to applied environment considering to determine that it recommends value is between 3～5.

Then, shown in step 309, corresponding each the candidate Midamble codeword sequence of subscriber terminal equipment, the time delay envelope according to after the multiframe merging carries out Path selection by certain criterion.With reference to figure 5-1 to Fig. 5-3, be depicted as the several method that carries out Path selection according to the time delay envelope.The method of described Path selection comprises:

Method C1, the routing resource first is shown in Fig. 5-1: by a series of X paths of choosing mould value maximum in the time delay envelope after relatively.Wherein, parameter X is a positive integer, and the value of recommendation is between 1～5.Especially, as a kind of special circumstances, desirable X=1 promptly directly chooses that paths of mould value maximum.

Method C2, routing resource second is shown in Fig. 5-2: at first by a series of paths that relatively obtain mould value maximum, and remember that its mould value is P _Max(unit: dB); Choose all mould values then greater than (P _Max-T ₁) (unit: path dB).Wherein, parameter T ₁Be a default threshold value, its value be one greater than 0 arithmetic number, for example desirable T ₁=3dB.

Method C3, routing resource the third, shown in Fig. 5-3: the mean value of the mould value in all paths in the calculation delay envelope at first, and be designated as P _Avg(unit: dB); Choose all mould values then greater than (P _Max+ T ₂) (unit: path dB).Wherein, parameter T ₂Be a default threshold value, its value be one greater than 0 arithmetic number, for example desirable T ₂=6dB.

Notice that above-mentioned each method can be used in combination, for example, can adopt method second to obtain a collection of path earlier, and then according to the method first, if gained path values number greater than X, the X paths of delivery value maximum therein more then.

Subsequent, as step 310, subscriber terminal equipment will carry out addition by the path values on the selected path of step 309, obtain " likelihood value " (Likelihood) H ^m(m=1 wherein, 2,3,4 respectively corresponding 4 candidate Midamble codeword sequences).If the Path selection index value result who is obtained by step 309 is S ^m, likelihood value H then ^mThe available following formulate of calculating:

$H^m=\left|\underset{k\∈S^m}{\mathrm{\Σ}}D{P}_k^m\right|,$ For m=1,2,3,4;

Note the path values DP in the following formula in the time delay envelope _k ^mMay be a plural number, the situation when for example adopting aforementioned slip correlation technique A3 and time delay envelope computational methods B3 be so may need delivery value (perhaps similar operations) to remove phase information.

Subsequent, shown in step 311, subscriber terminal equipment is found out the candidate Midamble codeword sequence of likelihood value maximum, remembers that its sequence number is M (1≤M≤4), and then this step is operated available following formulate:

$M=\arg \underset{m}{\max }\left\{H^m\right\}$

In the following formula, function m ax () is illustrated in the sequence by a series of computings of comparing the back maximizing.

Then, shown in step 312, subscriber terminal equipment is according to " likelihood value " of maximum likelihood value Midamble codeword sequence M and other all candidate Midamble codeword sequences, and " confidence level " that calculate Midamble codeword sequence M (Reliability) and is designated as R.Wherein, calculate the likelihood value that " confidence level " R can be taken as Midamble codeword sequence M, the ratio of the likelihood value of other all candidate Midamble codeword sequences with all, that is adopt following formula to obtain:

$R=\frac{H^M}{\underset{m\≠M}{\mathrm{mean}}\left\{H^m\right\}};$

In the following formula, function m ean () represents to average calculating.

In addition, as a kind of alternative selection, " confidence level " R also can be calculated as follows:

$R=\frac{H^M}{\underset{m\≠M}{\max }\left\{H^m\right\}};$

Then, as step 313, subscriber terminal equipment will be compared by " confidence level " R and default threshold T of step 312 calculating gained: if R 〉=T, then enter step 314, output Midamble codeword sequence sequence number M will export detection " refusal " sign simultaneously and be changed to " vacation " (False), indicate in second step (Accept) testing result of Midamble codeword sequence testing process " acceptance ", promptly produce " acceptance " signal, and successfully finish; Otherwise, if R＜T, then enter step 315, to export detection " refusal " and (Rejection) indicate and be changed to " very " (True), promptly produce " refusal " signal, and indicate that second step detects to fail, that is all candidate Midamble codeword sequences equal " insincere ", this moment the cell search procedure before will turning back to, for example initial cell search first step is rapid or the frequency search phase, carries out relevant search, synchronously and work such as detection again.

Here, the value of threshold parameter T is one and is greater than or equal to 1 arithmetic number that it is to Midamble detection algorithm performance important influence.When the value of T is big more, mean that thresholding is strict more, thereby the probability of false detection that the Midamble codeword sequence detects is just low more, the ability of the incoming event of debug simultaneously is also strong more, but this moment, correct detection probability also can be subjected to a certain degree influence.On the other hand, when the value of T more little, mean that thresholding is loose more, though this moment, correct detection probability can improve, but probability of false detection also can increase simultaneously, and the elimination ability to wrong incoming event has also weakened---under the extreme case, a kind of special circumstances as Midamble codeword sequence detection method disclosed in this invention, when choosing T=1.0, to always accept testing result and can not be changed to " very " detecting " refusal " sign, though this moment, correct detection probability was higher, probability of false detection also can correspondingly increase, and this detection method no longer possesses the ability of debug input simultaneously.In sum, at concrete applied environment with realize to consider, should carefully select thresholding T, carry out between each design objective repeatedly compromise after, make the overall performance of Midamble codeword sequence detection algorithm reach optimum.For example, for following method and parameter combinations: slip correlation technique A1, time delay envelope computational methods B1, routing resource C1 and multiframe merge frame number F=5, and the recommendation value of described threshold parameter T is 2.0.

In addition, as a kind of possibility, if cell search first step rapid (detecting the probability of success in order to improve) passes to SYNC-DL code word and the corresponding synchronous positional information thereof of second step greater than a candidate, then second step can be carried out related detection to them successively by parallel or serial mode, if wherein all detect and all produce " refusal " signal, then second step also will produce " refusal " signal.Otherwise, if wherein have at least one-time detection to produce " acceptance " signal, then second step also will produce " acceptance " if signal---have more than one-time detection to produce " acceptance " signal, promptly produced a plurality of " confidence levels " higher Midamble codeword sequence, then can get wherein the output of that the highest Midamble codeword sequence of " likelihood value " as second step.

Further, utilize and disclosed in this inventionly a kind ofly divide the detection method of carrying out the Midamble codeword sequence in the synchronous time division multi-address system, can also be used to realize some other miscellaneous function at sign indicating number.For example:

(1) when adopting slip correlation technique A3 and time delay envelope computational methods B3, the phase value of the time delay envelope path values after can merging by multipath (for the Midamble codeword sequence output M of likelihood value maximum), carry out rough frequency departure and estimate that its computing formula is as follows:

$\mathrm{\Δ}\hat{f}=\frac{1}{2\mathrm{\π}{T}_{c}P}\×\arg \left\{\underset{k\∈S^M}{\mathrm{\Σ}}{D}_k\right\}$

In the following formula, the phase value operation of a plural number is got in function arg () representative, its codomain be [π, π), Represent frequency departure to estimate, and other parameter is still continued to use aforementioned related definition.The frequency departure estimated value of gained Can be used to carry out once rough frequency adjustment.

(2) utilize the time delay envelope D that is produced ^M(for the Midamble codeword sequence output M of likelihood value maximum) can provide (comparing with the rapid output of initial cell search first step) synchronizing information and path position information more accurately.Particularly, at corresponding Path selection results set S ^MIn, contain a collection of based on the resulting active path positional information of Midamble codeword sequence M, these information are than more accurate by the rapid resulting sync bit of initial cell search first step, because it only is that the correlated results of 64 chips is resulting that the latter is based on length, and only comprise the positional information of a power maximum path.

The subsequent module of search of initial zone second step, as (Tracking) such as route searching (Path Search) module and synchronous tracking modules, can utilize this synchronizing information and path position to start working, thereby accelerate their initial convergence process, and improve its accuracy as initial information.

Figure 6 shows that according to the present invention in TD-SCDMA system initial cell search procedure second step, detect the structured flowchart of a kind of device of Midamble codeword sequence.Wherein, Midamble received signal sampling extractor 60 receives the sample sequence in the corresponding Midamble signal " search window " in the present frame according to relevant timing information; Midamble codeword sequence maker 61 generates 4 candidate Midamble sequence code words according to the code character sequence number; A collection of sliding correlation detector 62 ₁-62 ₄To receive the Midamble signal sample sequence slides relevant in " search window " with all candidate Midamble codeword sequences respectively; A collection of time delay envelope calculator 63 ₁-63 ₄Relevant output result calculates respectively corresponding to the time delay envelope in " search window " of each candidate Midamble codeword sequence according to sliding; A collection of multiframe combiner 64 ₁-64 ₄With each envelope respectively with frame before in obtain, merge corresponding to the time delay envelope of same candidate Midamble codeword sequence, and preserve amalgamation result; A collection of path selector 65 ₁-65 ₄According to time delay envelope after the multiframe merging, corresponding each candidate Midamble codeword sequence, carry out Path selection by certain criterion; A collection of likelihood value calculator 66 ₁-66 ₄, be used for corresponding each candidate Midamble codeword sequence, respectively the value on the selected path in the time delay envelope is merged, obtain corresponding " likelihood value "; Maximum value detector 69 is used to find out " likelihood value " maximum candidate Midamble codeword sequence; " confidence level " calculator 67 calculates " confidence level " of maximum likelihood value Midamble codeword sequence according to " likelihood value " of maximum likelihood value Midamble codeword sequence and other all candidate Midamble codeword sequences; Comparator 68 is used for " confidence level " result of calculation and a default thresholding are compared, and according to comparative result the value that output detects " refusal " sign is set.

Figure 7 shows that the flow chart that applies the present invention to a kind of method in the TD-SCDMA system initial cell search procedure.Wherein, step 70 represents initial cell search first step rapid, carries out SYNC-DL codeword detection and (rough) frame synchronization.Enter step 71 then, correspond to search of initial zone second step, according to the code character of determining by the SYNC-DL code word, and relative synchronous information, carry out the detection of Midamble codeword sequence.Wherein, after step 71 adopts by a kind of Midamble codeword sequence detection method disclosed by the invention and device, in step 72, can whether produce " refusal " signal and control relevant handling process: if " refusal " of second step is masked as " vacation " according to second step, show that second step has successfully detected one " confidence level " higher Midamble codeword sequence, can start subsequent module this moment, comprise route searching (Path Search), follow the tracks of synchronously (Tracking), automatic frequency control (AFC) and search of initial zone third step etc. utilize this Midamble codeword sequence to detect and carry out relevant work; On the other hand, if " refusal " of second step is masked as " very ", show that second step fails to detect one " confidence level " enough high Midamble codeword sequence, this has multiple reason and causes, and comprising: (1) SINR is low excessively; (2) input SYNC-DL code word mistake; (3) input synchronizing information mistake; (4) frequency mistake; Or the like.At this moment, as shown in Figure 7, can get back to first step and carry out related detection and Synchronous Processing (select, also can get back to more the frequency search phase of front is carried out relevant search again) again, and re-execute second step according to new result as another kind.If the number of times of finding second step refusal greater than certain threshold value C after (step 73), then subscriber equipment will be abandoned the search on this frequency, and continue the enterprising line search of next frequency (perhaps carrying out other system, as the search of W-CDMA and gsm system).Adopt the benefit of this control flow to be, for those wrong abnormal conditions, by by a kind of Midamble codeword sequence detection method disclosed by the invention and device, can as early as possible these situations be got rid of, avoid error propagation and cause subsequent step to carry out meaningless operation.Can shorten the whole search of initial zone time effectively like this, this has crucial meaning for the search of initial zone in the often more abominable TD-SCDMA system of operational environment.

The schematic diagram that applies the present invention to the another kind of pipeline organization method in the TD-SCDMA system initial cell search procedure shown in Figure 8.(Serial) working method is relative with " serial " shown in Figure 7, here the first step and second step have adopted a kind of " walking abreast " working method, promptly except the starting stage, the first step and second step simultaneously by a kind of " streamline " (Pipeline) mode work.With reference to figure 8, each first step and the operation of second step all are to finish by handling altogether the data of F frame, and wherein F is a positive integer, for example desirable F=5.At first, only first step work (corresponding step 800) in initial F frame, and its result is passed to second step in the beginning of the F frame of following.In subsequent F frame, the result of F frame first step before second step (step 810) basis carries out relevant the processing; Simultaneously first step (step 801) carries out relevant work (perhaps, also the output result and the result of first step before can be merged to improve accuracy by certain mode) again; After this F frame disposes, judge whether second step has produced the refusal signal: if not, then should " streamline " working method successfully finish, proceed the follow-up relevant initial cell search procedure of finishing dealing with; If then in following F frame, second step will be carried out related detection according to the output result of this first step again and be handled.It shown in Fig. 8 latter event.Similarly, in the F frame of following, first step (step 802) and second step operation (step 811) still concurrent working.If behind this F frame end, second step still produces the refusal signal, then above process will constantly be carried out by this " streamline " mode, produce acknowledge(ment) signal up to certain second step.For example, in Fig. 8, behind subsequent F frame, second step (step 812) does not produce " refusal " signal (that is accepting Midamble codeword sequence testing result), and then " streamline " mode successfully finishes, and system's control will start follow-up relevant module; Simultaneously, the output result of this first step (step 803) is dropped." streamline " mode is as shown in Figure 8 compared with " serial " mode of routine as shown in Figure 7, though complexity increases (because the first step and second step need to handle simultaneously), its search time, (particularly under abominable operational environment) but can shorten greatly.For example, if in " serial " working method shown in Figure 7, the first step and second step each need execution to finish for N time, promptly needs 2*N time altogether; Then by as shown in Figure 8 " streamline " mode, only need just can finish for N+1 time.When the N value is big, can save for nearly 50% search time by the work of " streamline " mode.And the key of realization " streamline " mode as shown in Figure 8, be to provide " acceptance " or " refusal " signal in second step, the judgement foundation that stops or proceed as " streamline "---and a kind of Midamble sequence code word detection method and the device that propose according to the present invention can satisfy above-mentioned requirements well.

So far, described a kind of preferred forms of the present invention in conjunction with the accompanying drawings in detail.Those of ordinary skill in the art should recognize, here be used to describe various logical units of the present invention, module, circuit and algorithm steps etc., can adopt electronic hardware (electronic hardware), computer software (computer software) or their combination to put into effect.Here all being to describe according to their function usually to various elements, unit, module, circuit and step, adopting hardware or software during realization actually, is that concrete application and the design constraint by whole system decides.Those of ordinary skill in the art should recognize the interchangeability of hardware and software under specific circumstances, and can adopt best mode to realize a kind of method that detects the Midamble training sequence in TD-SCDMA system initial cell search procedure described in the invention at concrete application.

For example, here be used to describe various logical units of the present invention, module, circuit and algorithm steps etc., can be in the following ways or their combination realize, comprising: digital signal processor (DSP), special purpose integrated circuit (ASIC), field programmable gate array (FPGA) or other programmable logic device, (discrete) gate (gate) or transistor (transistor) logic of separating, the hardware component (for example register and FIFO) that separates, carry out the processor of a series of firmwares (firmware) instruction, traditional programming software (programmable software) and relevant processor (processor) etc.Wherein, processor can be microprocessor (microprocessor), also can be traditional processor, controller (controller), microcontroller (microcontroller) or state machine (state machine) etc.; Software module can be present in RAM memory, flash memory (flashmemory), ROM memory, eprom memory, eeprom memory, register, hard disk, moveable magnetic disc, CD-ROM or any existing known storage medium.

The obviously clear and understanding of those of ordinary skill in the art, the most preferred embodiment that the present invention lifted only in order to explanation the present invention, and is not limited to the present invention, the present invention for the technical characterictic among each embodiment, can combination in any, and do not break away from thought of the present invention.According to a kind of detection method and equipment that is applied to the Midamble sequence in the TD-SCDMA mobile communication system disclosed by the invention, can there be many modes to revise disclosed invention, and except the above-mentioned optimal way that specifically provides, the present invention can also have other many embodiment.Therefore, all genus are conceived getable method of institute or improvement according to the present invention, all should be included within the interest field of the present invention.Interest field of the present invention is defined by the following claims.

Claims (33)

1. detect the method for middle guiding code sequence in the TDS-CDMA system, this method comprises the following step:

1: middle guiding code sequence received signal sampling extraction step, according to the relevant timing information that provides suddenly by initial cell search first step, according to certain sampling and receive mode, extract near part and the received signal of middle guiding code sequence in the present frame, obtain a sample sequence r;

2: middle guiding code sequence generates step, according to by the determined code character of the rapid detected descending synchronous code of initial cell search first step, for each candidate's middle guiding code sequence in this code character, generates a sequence s respectively;

3: the slip correlation step, with lead in receiving coded signal sample sequence r respectively with each candidate middle guiding code sequence s slide by certain mode relevant after, obtain relevant output sequence C;

4: time delay envelope calculation procedure, calculate time delay envelope D respectively according to relevant output sequence C corresponding to each candidate's middle guiding code sequence;

5: the multiframe combining step, with each envelope D respectively with former frame in obtain, merge by certain merging mode corresponding to the time delay envelope D of same candidate middle guiding code sequence, and preserve amalgamation result; After the merging of F frame,, obtain a time delay envelope DP corresponding to each candidate's middle guiding code sequence;

6: the Path selection step, according to time delay envelope DP after the multiframe merging, corresponding each candidate middle guiding code sequence, carry out Path selection by certain routing criterion, obtain set of paths S;

7: the likelihood value calculation procedure, lead a yard codeword sequence in corresponding each candidate, respectively the value that is positioned on the selected path S among the time delay envelope DP is merged, obtain corresponding " likelihood value " H;

8: maximum detects step, finds out the candidate middle guiding code sequence of " likelihood value " H maximum, and its sequence number is M;

9: the confidence level calculation procedure according to " likelihood value " of maximum likelihood value middle guiding code sequence and other all candidate middle guiding code sequences, calculates " confidence level " R of maximum likelihood value middle guiding code sequence;

10: comparison step compares " confidence level " R and a default thresholding T;

11: detect refusal sign output step,, the value that output detects " refusal " sign is set according to the comparative result of comparison step;

12: middle guiding code sequence sequence number output step, when output detection " refusal " is masked as " vacation ", accept testing result, the sequence number M of output maximum likelihood value middle guiding code sequence.

2. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 1, it is characterized in that in the step 1, described sampling and receive mode are: according to certain sampling rate, receive middle guiding code sequence in the search window, with and near the sampled value of data; This search window comprise length be 144 chips in lead L chip before the coded signal part position, and the sampled data in R chip afterwards reaches and comprises the interior data sampling of L+R+144 chip altogether.

3. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 2, it is characterized in that the multiple of described sampling rate is 2, can sample and receive the individual data chip of 2 (L+R+144).

4. as detecting the method for middle guiding code sequence in claim 2 or the 3 described TDS-CDMA system, it is characterized in that described L and R value are 16.

5. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 2, it is characterized in that, lead coded signal part position in described and be original position P by the rapid resulting descending pilot frequency time slot part of initial cell search first step _DwPTSDerived; Its derived expression: in lead coded signal part original position be P _Midamble=P _DwPTS-352-16.

6. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 1, it is characterized in that, in the step 1, described sampling and receive mode: extract and receive length and be and lead in 144 chips in the coded signal part in back 128 chips, or the interior data sampling of 128 chips of middle a certain end.

7. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 1, it is characterized in that in the step 3, described slip correlation step comprises:

3.1: with each length is that the candidate middle guiding code sequence s of N gets conjugation, obtains the sequence s* of length N;

3.2: at i constantly, with the sample sequence r that receives _iPursue element with sequence s* and multiply each other, obtaining a length is the output sequence y of N _i

3.3: according to certain correlation technique, obtain relevant output C _i

8. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 7, it is characterized in that described correlation technique is: with sequences y _iIn all N element, by obtaining relevant output C after the addition _i, that is: $C_i=\underset{k=1}{\overset{N}{\mathrm{\Σ}}}{y}_{i,k}.$

9. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 7, it is characterized in that described correlation technique comprises the following step:

3.3.1: with sequences y _iBe divided into N/P cross-talk sequence, P is every cross-talk sequence length;

3.3.2: with the addition of described N/P cross-talk sequence, obtain N/P part correlation output { p ₁, p ₂..., p _N/P, that is: $p_k=\underset{j=1}{\overset{P}{\mathrm{\Σ}}}{y}_{i,(k+1)\×P+j},k=\mathrm{1,2},\·\·\·,N/P;$

3.3.3: with above-mentioned part correlation dateout square merging, obtain relevant output C _i, that is:

$C_i=\underset{k=1}{\overset{N/P}{\mathrm{\Σ}}}{\left|p_k\right|}^2.$

10. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 7, it is characterized in that described correlation technique comprises the following step:

3.3.1: with sequences y _iBe divided into N/P cross-talk sequence, P is every cross-talk sequence length;

3.3.2: with the addition of described N/P cross-talk sequence, obtain N/P part correlation output { p ₁, p ₂..., p _N/P, that is: $p_k=\underset{j=1}{\overset{P}{\mathrm{\Σ}}}{y}_{i,(k-1)\×P+j},k=\mathrm{1,2},\·\·\·,N/P;$

3.3.3: with above-mentioned part correlation dateout conjugate multiplication, and addition, obtain relevant output C _i, that is: $C_i=\underset{k=1}{\overset{N/P-1}{\mathrm{\Σ}}}(p_k^{*}\×p_{k+1}).$

11. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 8, it is characterized in that, step 4, the calculating of time delay envelope is by asking corresponding relevant output C _iSquare acquisition of mould value, that is: $D_k^m={\left|C_k^m\right|}^2,k=\mathrm{1,2},\·\·\·,2\×(L+R+1),m=\mathrm{1,2,3,4},$ Wherein, m represents the middle guiding code sequence sequence number in the code character.

12. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 8, it is characterized in that, step 4, the calculating of time delay envelope is to get relevant output C _iThe mould value obtain, that is: $D_k^m=\left|C_k^m\right|,k=\mathrm{1,2},\·\·\·,2\×(L+R+1),m=\mathrm{1,2,3,4},$ Wherein, m represents the middle guiding code sequence sequence number in the code character.

13. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 9, it is characterized in that, step 4, the calculating of time delay envelope is directly to get relevant output valve C _iAs the time delay envelope, that is: $D_k^m=C_k^m,k=\mathrm{1,2},\·\·\·,2\×(L+R+1),m=\mathrm{1,2,3,4},$ Wherein, m represents the middle guiding code sequence sequence number in the code character.

14. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 10, it is characterized in that, step 4, the calculating of time delay envelope is directly to get relevant output valve C _iAs the time delay envelope, that is: $D_k^m=C_k^m,k=\mathrm{1,2},\·\·\·,2\×(L+R+1),m=\mathrm{1,2,3,4},$ Wherein, m represents the middle guiding code sequence sequence number in the code character.

15. as detecting the method for middle guiding code sequence in the arbitrary described TDS-CDMA system of claim 11 to 14, it is characterized in that, step 5, the multiframe combining step comprises the following step:

5.1: whether judgment frame is counted greater than 1, as not, preserves the time delay envelope of present frame, and directly carry out step 5.3;

5.2: in this way, then each time delay envelope that present frame is produced obtains respectively with in the frame before, merges corresponding to the time delay envelope of same candidate's middle guiding code sequence, and preserves amalgamation result;

5.3: frame count is added 1;

5.4: whether judgment frame is counted greater than a parameter value F, in this way, and then corresponding to each candidate's middle guiding code sequence, a time delay envelope DP of note gained, and descend preface step 6; As not, then carry out the sampling of middle guiding code sequence received signal extract, slide relevant, time delay envelope, and the step that merges of multiframe again.

16. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 15, it is characterized in that described F value is between 3～5.

17. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 15, it is characterized in that the time delay envelope merges in the step 5.2, adopt method by the element addition.

18. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 15, it is characterized in that, step 6, Path selection comprises the following step:

6.1: by a series of paths that relatively obtain time delay envelope mould value maximum, and remember that its mould value is P _Max

6.2: choose all mould values greater than (P _Max-T ₁) the path, establishing this Path selection results set is S, parameter T1 is a default threshold value; Its value be one greater than 0 arithmetic number, desirable T ₁=3dB.

19. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 15, it is characterized in that, step 6, Path selection comprises the following step:

6.1: the mean value of the mould value in all paths in the calculation delay envelope, and be designated as P _Avg

6.2: choose all mould values greater than (P _Max+ T ₂) the path, establishing this Path selection results set is S, parameter T2 is a default threshold value, its value be one greater than 0 arithmetic number, desirable T ₂=6dB.

20. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 15, it is characterized in that step 6, Path selection step, be the X paths of choosing mould value maximum in the time delay envelope after relatively by a series of, establishing this Path selection results set is S.

21. as detecting the method for middle guiding code sequence in claim 18 or the 19 described TDS-CDMA system, it is characterized in that, after the step 6.2, as the path values number selected greater than X, then choose the X paths of mould value maximum more therein, establishing this Path selection results set is S.

22. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 20, it is characterized in that described parameter X is a positive integer, the value of recommendation is between 1～5.

23. as detecting the method for middle guiding code sequence in the arbitrary described TDS-CDMA system of claim 18 to 20, it is characterized in that, step 7, the likelihood value calculation procedure, lead a yard codeword sequence in corresponding each candidate, respectively the value that is positioned on the selected path S among the time delay envelope DP is merged, obtain likelihood value H ^m, $H^m=\left|\underset{k\∈S^m}{\mathrm{\Σ}}{\mathrm{DP}}_k^m\right|,m=\mathrm{1,2,3,4}.$

24. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 23, it is characterized in that, step 8, maximum detects step, and user terminal is found out the middle guiding code sequence of likelihood value maximum, remembers that its sequence number is M, 1≤M≤4, $M=\arg \underset{m}{\max }\left\{H^m\right\}.$

25. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 24, it is characterized in that, step 9, the confidence level calculation procedure, confidence level R:

$R=\frac{H^M}{\underset{m\≠M}{\mathrm{mean}}\left\{H^m\right\}};$

Function m ean () represents to average calculating.

26. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 25, it is characterized in that step 10, comparison step is that a R and a preset value T are compared, and obtains a comparative result, this preset value T is an arithmetic number, and T 〉=1.

27. detect the method for middle guiding code sequence in the TDS-CDMA system as claimed in claim 26, it is characterized in that step 11 detects the output of refusal sign and comprises following steps:

11.1: if R 〉=T then exports middle guiding code sequence sequence number M, will export detection " refusal " sign simultaneously and be changed to " vacation ", sign Cell searching second step middle guiding code sequence testing process " acceptance " testing result promptly produces " acceptance " signal, and successfully finishes;

11.2: if R＜T, then will export detection " refusal " sign and be changed to " very ", and promptly produce " refusal " signal, the sign Cell searching second step middle guiding code sequence testing process detects failure, that is the middle guiding code sequence of all candidates equal " insincere ", the cell search procedure before turning back to.

28. detect the device of middle guiding code sequence in the TDS-CDMA system, this device comprises a middle guiding code sequence received signal extractor, leads a yard codeword sequence maker in one;

This middle guiding code sequence received signal extractor with should in lead the input that yard equal circuit of the output of codeword sequence maker is connected a sliding correlation detector unit;

The output of this sliding correlation detector unit circuit successively connects a time delay envelope unit calculator, a multiframe combiner unit, a likelihood value unit calculator;

The output of described multiframe combiner unit also circuit connects the input of a path selector unit, and the circuit of output terminal of this path selector unit connects an input of this likelihood value unit calculator;

The output of this likelihood value unit calculator connects the input of a confidence level calculator and a maximum value detector respectively, and this maximum value detector output also circuit connect another input of confidence level calculator;

The output of described confidence level calculator also circuit connects a comparator.

29. detect the device of middle guiding code sequence in the TDS-CDMA system as claimed in claim 28, it is characterized in that described sliding correlation detector unit comprises 4 sliding correlation detectors that are connected in parallel.

30. detect the device of middle guiding code sequence in the TDS-CDMA system as claimed in claim 29, it is characterized in that, described time delay envelope unit calculator comprises 4 time delay envelope calculators that are connected in parallel, and each time delay envelope calculator correspondence this each sliding correlation detector that is connected in series.

31. detect the device of middle guiding code sequence in the TDS-CDMA system as claimed in claim 30, it is characterized in that, described multiframe combiner unit comprises 4 multiframe combiners that are connected in parallel, and each multiframe combiner correspondence this each time delay envelope calculator that is connected in series.

32. detect the device of middle guiding code sequence in the TDS-CDMA system as claimed in claim 31, it is characterized in that, described likelihood value unit calculator comprises 4 likelihood value calculators that are connected in parallel, and this each likelihood value calculator correspondence this each multiframe combiner that is connected in series.

33. detect the device of middle guiding code sequence in the TDS-CDMA system as claimed in claim 32, it is characterized in that, described path selector unit comprises 4 path selectors, and this each path selector corresponding circuits is connected between this each multiframe combiner and this each likelihood value calculator.

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