CN100362892C - Method and apparatus of initial cell search in time division synchronous CDMA system - Google Patents
Method and apparatus of initial cell search in time division synchronous CDMA system Download PDFInfo
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- CN100362892C CN100362892C CNB2004100256936A CN200410025693A CN100362892C CN 100362892 C CN100362892 C CN 100362892C CN B2004100256936 A CNB2004100256936 A CN B2004100256936A CN 200410025693 A CN200410025693 A CN 200410025693A CN 100362892 C CN100362892 C CN 100362892C
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Abstract
The present invention relates to a method and a device for service life division synchronous code division multiple access (TD-SCDMA) mobile communication systems to carry out initial sub-zone searches, which comprises a 1 bit relevant method and a relevant device applied to the first step of initial sub-zone searches and a serial/concurrent iteration method comprising the first step and the second step of initial sub-zone searches and has corresponding low processing complexity and a good performance, and the present invention can effectively shorten the initial sub-zone search time of TD-SCDMA systems under bad propagation condition. In the present invention, the 1 bit relevant method comprises steps and modules of path symbol extraction, reverse rotation, bit exclusiveor, 1 number statistics, power calculation, etc.; the serial/concurrent iteration method comprising the first step and the second step of initial sub-zone searches can make up performance loss brought by the 1 bit relevant method and the relevant device with low complexity of the present invention at certain degree.
Description
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, subscriber terminal equipment carries out the method and apparatus of search of initial zone (InitialCell Search).
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 is abbreviated as UE) 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 time division duplex (LCR-TDD) pattern (1.28Mcps) among 3G collaborative project (3GPP) the standard TS 25.221 (Release 4), perhaps provides among China Wireless Telecommunication Standar (CWTS) standard TSM 05.02 (Release3).The spreading rate of TD-SCDMA system is 1.28Mcps, each radio frames (RadioFrame) 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 uplink pilot time slot (UpPTS) 24 and descending pilot frequency time slot 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.The protection that DwPTS time slot 22 comprises 32 chips at interval 30 and 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) on P-CCPCH (Primary Common Control Physical Channel) channel on Midamble part received signal 28.Because each SYNC-DL code word 25 corresponding code character (Code Group), 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 (broadcast channel) information: after acquisition control multi-frame was synchronous, just can know had the BCCH 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 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.
The method of search of initial zone and device design thereof are one of important topics in the TD-SCDMA system design.On the one hand, because subscriber terminal equipment carries out often having only before the search of initial zone (even without any) system information seldom, and (for example may face more abominable channel circumstance, when the user is in cell edge or is in the shadow region), therefore require designed initial cell searching method to have good performance, can find Target cell within a short period of time, have robustness (robustness) preferably again simultaneously, can adapt to various start environment; On the other hand, require this design to have rational complexity again, avoid since the software/hardware resource consumption too much or power consumption a series of problems of implementation of bringing such as too big.
Especially, in the TD-SCDMA system, the rapid design of aforementioned initial cell search first step is particularly crucial to global design: because this moment subscriber terminal equipment also without any timing information, so often need by after in whole radio frames, carrying out carrying out a series of slip associative operations and subsequent treatment between received signal and one or more (maximum 32) alternative SYNC-DL code word, could determine the SYNC-DL code word that relevant timing information and power are the strongest, begin the relevant processing of search of initial zone second step then.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 TERMINALAPPARATUS), 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.
Prior art as shown in Figure 3 is a kind of rapid correlator of TD-SCDMA system initial cell search first step that is applied to.At first, receive data through at first sampling, analog-to-digital conversion and base-band digital matched filtering after, obtain receiving of the input of data signal samples stream as this correlator.Wherein, sampling rate generally is chosen as certain multiple of spreading rate, for example adopts 2 times of over-samplings, promptly carries out 2 samplings in each chip-spaced; Analog-to-digital conversion (ADC) is used for input analog sampling value is quantified as corresponding digital value, offers digital baseband unit and carries out a series of processing; The base-band digital matched filter is mainly used in outer interference of filtering band and noise, and typical value of the quantizing bit number M of its output digital signal is 6 or 8.After correlator receives the data sampling input, at first by 31 pairs of inputs of despining device I/Q two-way sampled value a
nCarry out obtaining b after the despining
nThis operation is corresponding with the rotary manipulation of transmitter terminal.Particularly, available following formula sign is operated in despining:
b
n＝a
n*(-j)
n (n＝0，1，2，…)
Wherein, a
nAnd b
nBe respectively input, the output symbol of despining device 31, subscript n is the input sample sequence number, and j is-1 unit root.In fact, with complex representation symbol a
nAnd b
n(wherein the corresponding I of real part road is an in-phase component, and the corresponding Q of imaginary part road is a quadrature component): a
n=ai
n+ j*aq
n, b
n=bi
n+ j*bq
n, then following formula is set up:
bi
n＝ai
n，bq
n＝aq
n (n＝4k，k＝0，1，2，…)
bi
n＝aq
n，bq
n＝-ai
n (n＝4k+1，k＝0，1，2，…)
bi
n＝-ai
n，bq
n＝-aq
n (n＝4k+2，k＝0，1，2，…)
bi
n＝-aq
n，bq
n＝ai
n (n＝4k+3，k＝0，1，2，…)
Therefore, this despining device can pass through realizations such as the exchange of I/Q road, negate and counting unit.Data sampling after the despining is divided into I and Q two-way, is moved into two groups of registers group 32 that respectively contain 64 M bit register respectively
1-64With 34
1-64As shown in Figure 3: in n-hour, each new data sample is moved into Q bit register 32 respectively
1With 34
1, the value of each register in each registers group is moved into the register on the right simultaneously.With the I road is example, this means register 32
iOriginal storing value is moved into register 32
I+1In, i=1 wherein, 2 ..., 63, and register 32
64In original storing value be dropped.Subsequent, the storing value of each register in two groups of registers group is according to the corresponding bit in the candidate SYNC-DL code word, respectively by a collection of " keeping/get negative " unit 33
1-64With 35
1-64Suppose that the storing value in the two groups of registers group in I road and Q road is respectively { bi
N, bi
N-1..., bi
N-63And { bq
N, bq
N-1..., bq
N-63; And hypothesis candidate SYNC-DL code word is { s
1, s
2..., s
64, s wherein
kValue be 0 or 1 (k=1,2 ..., 64), " keeping/get negative " unit 33 of the k on the I road then
kInput bi
N+1-k, s
kWith output ui
kConcern that available following formula characterizes:
Ui
k=bi
N+1-kIf s
k=1;
Ui
k=-bi
N+1-kIf s
k=0 (k=1,2 ..., 64)
Similarly, the k on the Q road " keeping/get negative " unit 35
kInput bq
N+1-k, s
kWith output uq
kConcern that available following formula characterizes:
Uq
k=bq
N+1-kIf s
k=1;
Uq
k=-bq
N+1-kIf s
k=0 (k=1,2 ..., 64)
Then, gained intermediate object program { ui
1, ui
2..., ui
64And { uq
1, uq
2..., uq
64Be transfused to two adders 36 respectively
1With 36
2, obtaining two adder output ci and cq, described additional calculation can characterize with following formula:
ci＝ui
1+ui
2+…+ui
64
cq＝uq
1+uq
2+…+uq
64
At last, the output ci of two adders and cq are admitted to a power calculator 37, output correlated results performance number p
NAvailable following formula characterizes:
p
N＝ci
2+cq
2
Correlator like this, has as shown in Figure 3 just been finished the correlation value calculation of n-hour.When a new sampled value input is arranged at every turn, this correlator just can produce a correlated results output through behind the aforesaid operations; Along with the continuous input that receives data sampling stream, this correlator has just produced a series of relevant outputs, thereby has finished " slip " correlated process like this.Then, the subsequent treatment module will be finished relevant synchronous and measuring ability according to these relevant outputs through after a series of processing.
Though though this device can reach optimum in theory performance, its complexity is very high, this means and to consume a lot of processor resources and more power consumption.Suppose 2 times of fast data samplings of received signal input employing (promptly corresponding each chip has two input samples inputs), and 6 bit quantizations are adopted in each sampling, because the SYNC-DL code word size is 64, the relevant addition and subtraction of each 64 12-bit of reality/imaginary part that needs of corresponding 64 samplings is operated, and carries out the relevant treatment needs of each SYNC-DL like this:
64*2*6400*2＝1,638,400
First step is finished in individual 12-bit addition and subtraction operation.For the search of initial zone of TD-SCDMA system,, therefore adopt correlator configuration as shown in Figure 3 will make the entire process process more complicated or consuming time owing to carry out the search and the synchronizing process of 32 SYNC-DL sign indicating numbers possibly simultaneously.Because if will carry out the relevant treatment of all 32 code words simultaneously, then in 5ms, finish altogether:
1,638,400*32＝52,428,800
Individual 12-bit addition and subtraction operation---this is that generally institute is unapproachable for present commercial software/hardware disposal ability.Therefore,, often can only in each 5ms, only carry out the relevant treatment of a collection of several SYNC-DL code words (for example 2 or 4 code words), and all alternative SYNC-DL code words are divided into many batches handle in order to realize this device.The purpose of doing like this is the requirement that reduces the software/hardware disposal ability, but the cost of being paid is to have elongated to carry out the rapid time that spends of initial cell search first step.Therefore, how reducing the complexity of this correlator, guarantee again synchronously simultaneously and detect performance to meet design requirement, is one of key issue that is faced in the initial cell search procedure design of TD-SCDMA system.
Carry out slip relevant treatment that all SYNC-DL code words are carried out in the entire frame, at International Patent Application Publication No. WO01/074103, denomination of invention is among " a kind of cell initial method of CDMA digital mobile communication system " (METHOD OF CELL INITIAL SEARCH IN CDMA DIGITALMOBILE TELECOMMUNICATION SYSTEM), disclose a kind of method that adopts so-called " feature window " (Characteristic Window), carried out carrying out in the TD-SCDMA system method of the first step in the search of initial zone.The main thought of this method is, utilizes the peculiar power envelope characteristic of DwPTS part in the TD-SCDMA frame structure, and it is synchronous to carry out rough DwPTS earlier, is carrying out the slip relevant treatment of all alternative SYNC-DL code words then near this synchronous points.Relevant owing to avoided in entire frame, sliding, so its processing complexity is compared reduction greatly with aforementioned schemes.The performance of this scheme depends on the validity of its " feature window " method to a great extent, but owing to only adopted power information, cause this method based on the DwPTS envelope trait, under low Signal to Interference plus Noise Ratio (SINR) condition, particularly during SINR＜0dB, be difficult to find at short notice correct DwPTS position; On the other hand, since distinctive each the time slot relative power envelope of TDD signal rise and fall may be bigger characteristic, when receiving the data of entire frame, often require the method for the gain controlling (AGC) of employing segmentation to adjust input signal---under the situation of this AGC effect, it is still obvious whether the power envelope characteristic of DwPTS part still can be retained or it is characterized in that, still remains further to be studied.In sum, although this scheme based on " feature window " can effectively reduce the rapid processing complexity of TD-SCDMA system initial cell search first step, but its performance in actual working environment has been subjected to the restriction of several factors, thereby remains further practice test.
Summary of the invention
The object of the present invention is to provide a kind of method and apparatus that carries out search of initial zone that is applied to subscriber terminal equipment in TD SDMA (TD-SCDMA) mobile communication system, can finish the detection of frame synchronization and synchronization code word within a short period of time under low Signal to Interference plus Noise Ratio (SINR) condition.
The present invention at first provide a kind of TD-SCDMA of being applied to system customer equipment receiver, carry out initial cell search first step " 1 bit " correlation process method in rapid, said method comprising the steps of:
Extract road symbol step, extract synchronous (I) and the sign bit on quadrature (Q) branch road of input data sampling stream respectively;
The despining step is carried out the despining operation with the sign bit on I/Q road, according to certain rules comprising possible I/Q road bit exchange and bit inversion operation;
Bit xor operation step is pursued the bit xor operation with candidate SYNC-DL code word respectively with nearest 64 sign bits in I/Q road;
Statistics " 1 " number step, the number of adding up " 1 " among the two groups of XOR output in the I/Q road result respectively;
The power calculation step, the statistics according to the I/Q road calculates related power.
Corresponding with said method, the present invention also provide a kind of TD-SCDMA of being applied to system customer equipment receiver, carry out initial cell search first step " 1 bit " relevant apparatus in rapid, described device comprises one or several " 1 bit " sub-relevant apparatus, be used for according to input data sampling stream and candidate's synchronization code word, produce corresponding a collection of correlated results output;
Wherein, described each " 1 bit " sub-relevant apparatus comprises:
Two sign bit extractors are used for extracting respectively synchronous (I) and the sign bit on quadrature (Q) branch road that the input data sampling flows;
A despining device is used for the sign bit on I/Q road is carried out the despining operation according to certain rules, comprising possible I/Q road bit exchange and bit inversion operation;
Two 64 bit shift registers are used for preserving respectively current 64 the data sampling bits in I/Q road, and the I/Q road bit after each despining is moved into;
Two batches of bit XOR unit are used for the value of two 64 bit shift registers is pursued the bit xor operation with candidate SYNC-DL code word respectively;
Two " 1 " number counters are used for adding up respectively the number that the two groups of XORs in I/Q road are exported results " 1 ";
A power calculator, the statistics according to the I/Q road calculates related power.
Further, the present invention also provide a kind of TD-SCDMA of being applied to system customer equipment receiver, carry out serial iteration method search of initial zone, that comprise first, second step, said method comprising the steps of:
The present invention also provide a kind of TD-SCDMA of being applied to system customer equipment receiver, carry out simultaneous iteration search of initial zone, that comprise first, second step, said method comprising the steps of:
Realize according to the present invention be used for TD-SCDMA system subscriber terminal equipment the method and apparatus that carries out search of initial zone, has relatively low relevant complexity, and can be under more abominable propagation conditions, reach the higher detection probability, can shorten the search of initial zone time in the TD-SCDMA system effectively simultaneously.Particularly, the invention provides relatively low correlation process method of a kind of complexity and device thereof, can solve the excessive problem of the rapid relevant treatment amount of calculation of TD-SCDMA system initial cell search first step preferably; Though this application process and device thereof can be introduced the performance loss of certain (about 2dB), by TD-SCDMA provided by the invention system initial cell search first step suddenly with the iterative processing scheme of second step, can address this problem preferably.
Objects and advantages of the present invention are by following description to the method and apparatus of search of initial zone in the TD-SCDMA system, and 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 rapid relevant apparatus that belongs to prior art of a kind of TD-SCDMA of being applied to system's initial cell search first step;
Fig. 4 is according to the flow chart that is applied to rapid " 1 bit " correlation technique of TD-SCDMA system initial cell search first step of the present invention;
Fig. 5 is for realizing the structured flowchart that is applied to rapid " 1 bit " the sub-relevant apparatus of TD-SCDMA system initial cell search first step of the present invention;
Fig. 6 is for realizing the structured flowchart of the TD-SCDMA of being applied to system's initial cell search first step of the present invention " 1 bit " relevant apparatus rapid, that comprise several " 1 bit " sub-relevant apparatus;
Fig. 7 is for realizing the TD-SCDMA of being applied to system's initial cell search first step of the present invention structured flowchart rapid, that comprise the synchronizer of " 1 bit " relevant apparatus;
Fig. 8 is in TD-SCDMA system initial cell search first step is rapid, uses the floating-point related algorithm and uses the present invention's simulation performance comparative result curve chart under the same conditions;
Fig. 9 is the flow chart that applies the present invention to a kind of serial iteration method in TD-SCDMA system first, second step of search of initial zone;
Figure 10 is the schematic diagram that applies the present invention to an example of a kind of serial iteration method in TD-SCDMA system first, second step of search of initial zone;
Figure 11 is the flow chart that applies the present invention to a kind of simultaneous iteration in TD-SCDMA system first, second step of search of initial zone;
Figure 12 is the schematic diagram that applies the present invention to an example of a kind of simultaneous iteration in TD-SCDMA system first, second step of search of initial zone;
Figure 13 carries out the performance chart of TD-SCDMA system search of initial zone first and second steps for using serial iteration method of the present invention.
Embodiment
Following according to Fig. 4～Figure 13, better embodiment of the present invention is described.
As shown in Figure 4, rapid " 1 bit " correlation technique of the TD-SCDMA system that is applied to initial cell search first step that proposes for the present invention.The core concept of this method is only to adopt the sign bit of input data sampling, be that each bit of I/Q road is handled, rather than employing many bits relevant treatment as shown in Figure 3, do that so a series of corresponding processing units are simplified greatly, reduce the processing expenditure and the power consumption of software/hardware.The flow process of this " 1 bit " correlation technique is described below in conjunction with Fig. 4.At first in step 40, according to the sampling input that receives data I/Q road, sign bit extractor (as among Fig. 5 50) extracts the sign bit { ai of I/Q circuit-switched data respectively
n, aq
n, wherein subscript n is the input sample sequence number, and ai
nAnd aq
nRepresent the sign bit on I and the Q road respectively.Described extraction sign bit step can be undertaken by following relation:
If input＞=0, then output=1; Otherwise, output=0
Perhaps,
If input＞=0, then output=0; Otherwise, output=1
Then, in step 41, despining device (as among Fig. 5 51) is to the I/Q road sign bit { ai of gained
n, aq
nCarry out the despining operation, obtain { bi
n, bq
n, bi wherein
nAnd bq
nRepresent respectively on I and the Q road through the sign bit after the despining operation.Its method is consistent with the described despining operation of the Fig. 3 in the aforementioned background art, but owing to only relate to bit operating here, so original " getting negative " operation available " bit negate " simple realization, that is:
bi
n＝ai
n，bq
n＝aq
n (n＝4k，k＝0，1，2，…)
bi
n＝aq
n，bq
n＝~ai
n (n＝4k+1，k＝0，1，2，…)
bi
n＝~ai
n，bq
n＝~aq
n (n＝4k+2，k＝0，1，2，…)
bi
n＝~aq
n，bq
n＝ai
n (n＝4k+3，k＝0，1，2，…)
Wherein, operator ~ x represents the inversion operation to bit x, that is ~ 0=1, ~ 1=0.Subsequent, in step 42, in n-hour, with two groups of nearest 64 bit { bi of the shift register on the I/Q road (52 among Fig. 5,53) reception
N, bi
N-1..., bi
N-63And { bq
N, bq
N-1..., bq
N-63, by two batches of bit XOR unit (54 among Fig. 5 and 55), respectively with candidate SYNC-DL code word { s
1, s
2..., s
64(s wherein
kValue be 0 or 1, subscript k=1,2 ..., 64) corresponding bit carry out bit XOR (bitexclusive OR) operation, obtain two groups of XORs output { ui on the I/Q road
1, ui
2..., ui
64And { uq
1, uq
2..., uq
64.Particularly, on the I road, respectively with bi
N+k-1Code word bits s with correspondence
kCarry out XOR, obtain output:
ui
k＝bi
N+1-ks
k (k＝1，2，…，64)
Wherein, operator represents xor operation, and its I/O is closed and is:
00＝0
01＝1
10＝1
11＝0
Similarly, on the Q road, respectively with bq
N+k-1Code word bits s with correspondence
kCarry out XOR, obtain output:
uq
k＝bq
N+1-ks
k (k＝1，2，…，64)
Then, in step 43, use " 1 " number counter (56 among Fig. 5) to add up two groups of xor operation result { ui on I road and the Q road respectively
1, ui
2..., ui
64And { uq
1, uq
2..., uq
64In the number of " 1 ", obtain exporting ci and cq.This step can be characterized by with formula:
ci＝ui
1+ui
2+…+ui
64
cq＝uq
1+uq
2+…+uq
64
Because input ui
kAnd uq
kBe a bit, so output ci and the equal value of cq are in [0,64] scope.At last, in step 44,, calculate n-hour related power output p by power calculator (57 among Fig. 5) according to input ci and cq value
N, wherein computing formula is as follows:
p
N＝(32-ci)
2+(32-cq)
2
Correlator like this, has as shown in Figure 3 just been finished the correlation value calculation of n-hour.When a new sampled value input is arranged at every turn, this correlator just can produce a correlated results output through behind the aforesaid operations; Along with the continuous input that receives data sampling stream, this correlator has just produced a series of relevant outputs, thereby has finished " slip " correlated process like this.Then, the subsequent treatment module will be finished relevant synchronous and measuring ability according to these relevant outputs through after a series of processing.
As shown in Figure 5, for realizing rapid " 1 bit " the sub-relevant apparatus 500 of the TD-SCDMA of being applied to system's initial cell search first step of the present invention
1Structured flowchart.This device has been realized " 1 bit " correlation technique as shown in Figure 4.After this device receives the data sampling input, at first by two sign bit extractors 50
1With 50
2, extract synchronous (I) and the sign bit on quadrature (Q) branch road that the input data sampling flows respectively.Then, carry out the despining operation by 51 pairs of despining devices input I/Q two-way sampled value, because the despining operation is the cycle with 4, and input I/Q road is a bit, so can adopt means simple realization such as truth table.Then, will be moved into two 64 bit shift registers 52 and 53 through the I/Q road bit after the despining respectively.Wherein, each 64 bit shift register has been preserved the sign bit of nearest 64 I or the sampling of Q circuit-switched data, when having new data sampling sign bit to enter, carry out a shifting function (shift out abandon the oldest sign bit) at every turn, and new data sampling sign bit is moved into.Then, by two batches of bit XOR unit 54
1-64With 55
1-64, be used for the bit value of two the 64 bit shift registers in I/Q road is pursued the bit xor operation with candidate SYNC-DL code word respectively.Then, by two " 1 " number counters 56
1With 56
2Be used for adding up respectively the two groups of XOR output results' in I/Q road " 1 " number, this operates on some digital signal processor (DSP) can perhaps also can adopt the combination simple realization of a series of logic gates based on hardware using simply with one or several instruction realizations.At last, by power calculator 57, the statistics according to above-mentioned I/Q road calculates related power.This power calculation provides in front, and available two squarers and three add/subtracter realizes; Perhaps also can adopt look-up table and an adder to reduce complexity.The wherein said logical block of tabling look-up is used to realize function f (x)=(32-x)
2, wherein the span of integer x is [0,64].
As shown in Figure 6, for realizing the TD-SCDMA of being applied to system's initial cell search first step of the present invention structured flowchart rapid, that comprise " 1 bit " relevant apparatus of several described " 1 bit " sub-relevant apparatus.This device has comprised the sub-relevant apparatus 500 of n (n＞=1) individual aforesaid " 1 bit "
1-nWherein, receive data sampling stream and be admitted to this n " 1 bit " sub-relevant apparatus; Simultaneously, each " 1 bit " sub-relevant apparatus is handled a candidate SYNC-DL code word, and the SYNC-DL code word that each " 1 bit " sub-relevant apparatus is handled has nothing in common with each other.Like this, adopt relevant apparatus as shown in Figure 6, just can realize finishing simultaneously a plurality of SYNC-DL code words are carried out " slip " relevant process.Notice that because described " 1 bit " sub-correlator has relatively low complexity, it is relevant therefore to allow to handle a plurality of SYNC-DL code words simultaneously in every frame, and still keeps reasonably total complexity.On the other hand,, before the next frame data arrive, adopt same relevant apparatus as shown in Figure 6, can continue to handle a collection of or several candidate SYNC-DL code words in addition if the time allows.Like this, adopt " 1 bit " relevant apparatus shown in 6, just can realize in a frame, carrying out the relevant treatment of a plurality of SYNC-DL code words with rational complexity.Particularly, according to conditions such as software/hardware resources, the designer can be divided into B with all pending N candidate SYNC-DL code words and criticize, and handles the individual candidate SYNC-DL of ceil (N/B) code word at most for every batch, and wherein ceil (x) function returns the smallest positive integral that is greater than or equal to input variable x; And in continuous M (M＞=1) frame, finish the relevant treatment of a collection of candidate SYNC-DL code word and corresponding subsequent synchronously and detect and handle at every turn.Like this, through the data processing of M*B frame at least, and, just can finish the rapid process of TD-SCDMA system initial cell search first step through after the final judgement.
As shown in Figure 7, for realizing that the present invention is applied to the rapid and structured flowchart that comprise a kind of synchronizer of " 1 bit " relevant apparatus of TD-SCDMA system initial cell search first step.How this installation drawing uses " 1 bit " provided by the invention relevant apparatus if having embodied, realize the rapid processing procedure of whole TD-SCDMA system's initial cell search first step.At first, receive data sampling,, in each frame, produce the related power envelope result output of a collection of correspondence according to current pending candidate SYNC-DL code word through correlator 70.Correlator described here promptly uses low complex degree of the present invention " 1 bit " relevant apparatus to realize.Then, correlation decimator 71 is according to the related power envelope that is generated in every frame, by the part correlation value and the corresponding position thereof of extracting someway wherein.For example, can be according to as International Patent Application Publication No. WO03/028399, denomination of invention being disclosed a kind of method among " small region search method and communication terminal device " (CELL SEARCH METHOD AND COMMUNICATION TERMINAL APPARATUS), each frame (for example is divided into some segments, every section 4 chip lengths, totally 1600 " segments "), and search for maximum related value piecemeal, and the maximum in only keeping every section.The purpose of doing like this is the purpose of saving memory space in order to reach.Because if keep all the related power envelopes in every frame, suppose to adopt 2 times of over-samplings, then corresponding each SYNC-DL code word needs altogether:
6400*2＝12,800
Individual memory cell; Therefore, (particularly when handling under the situation of a plurality of SYNC-DL code words in every frame) needs more memory spending, to realizing causing bigger burden.Therefore, in TD-SCDMA system initial cell search first step was rapid, this correlation decimator 71 was necessary.Certainly, except a kind of method of above-mentioned introduction, also can adopt other to select method and reach similar purpose.Then, by interframe combiner 72,, merge by certain mode with related power envelope continuous multiple frames, after selecting through the correlation decimator.In order to suppress to disturb and The noise, improve correct detection probability, be necessary related power output result based on a plurality of frames, adjudicate; And merging method described here is meant the related power envelope in continuous multiple frames output, according to the method for selecting of correlation decimator 71, by certain way they is superimposed upon in the scope corresponding to a frame.For example, corresponding aforementioned a kind of correlation of introducing is selected method, the related power value of selecting in corresponding same section in all frames can be carried out addition, so just obtained corresponding to the power envelope after the stack in the frame scope, this power envelope contains 1600 performance numbers (difference is corresponding each " segment ") altogether.Then, to each candidate SYNC-DL code word, power envelope maximum value search device 73 is according to the corresponding related power envelope of the output of interframe combiner, search for a relevant peaks of performance number maximum, and write down the performance number and the corresponding sync bit thereof of this relevant peaks.For example, a kind of method and corresponding interframe combiner selected for aforementioned introduction, this means will be in the related power envelope that contains 1600 performance numbers of corresponding each SYNC-DL candidate codewords, search for a maximum, write down the position (i.e. " segment " sequence number in a frame) of its appearance simultaneously.At last, after obtaining the relevant peaks of all candidate SYNC-DL code words, by relevant peaks maximum value search device 74, one or more relevant peaks performance number that search is wherein maximum, and export the appearance position and the corresponding candidate SYNC-DL code word of its (), so just finished the rapid whole process of TD-SCDMA system initial cell search first step.It is to be noted, general, as long as search of initial zone finds a sub-district that signal is the strongest to insert, but relevant peaks maximum value search device 74 can be configured to export more than a sync bit and SYNC-DL code word thereof, why do like this, be because (particularly when subscriber terminal equipment is in the edge of a plurality of sub-districts) to have the relevant peaks power ratio of a plurality of candidate SYNC-DL code words more approaching, first step is just all exported them like this, and do further judgement, thereby reach the raising correct detection probability by follow-up cell search procedure (for example search of initial zone second step), and the purpose that shortens search time.
As shown in Figure 8, in TD-SCDMA system initial cell search first step is rapid, uses the floating-point related algorithm and use the present invention, simulation performance comparative result curve chart under the same conditions.Wherein, the method that provides in the invention preamble introduction, International Patent Application Publication No. WO03/028399 has been provided for correlation decimator wherein and interframe merging method.Channel condition is white Gaussian noise channel (AWGN).Need to prove in addition, so-called " floating-point arithmetic ", be meant the quantification treatment of not carrying out the M bit for received signal, and all processing modules all adopt the reception data sampling input of relocatable---therefore, the performance of so-called " floating-point arithmetic " should be under the identical prerequisite of other condition, carries out the upper limit of the algorithm performance after any quantification treatment; In other words, any algorithm through quantification treatment, institute under the same conditions reaches performance, can not be better than the performance of corresponding " floating-point arithmetic ".In fact, according to relevant simulation result and practical experience, in mobile communication system, generally get the algorithm performance that M=6 ~ 8 bit quantizations are handled, the performance of " floating-point arithmetic " of very approaching correspondence, this also is the reason why existing most of mobile communication system are operated in this quantizing bit number scope.As a comparison, " 1 bit " relevant programme that the present invention proposes, owing to only the sign bit that receives data sampling has been carried out handling (can regard a kind of " 1 bit " quantization scheme as), can make a series of associated processing devices be able to a certain degree simplification, thereby greatly reduce the complexity of the relevant treatment of TD-SCDMA system initial cell search first step in rapid; And, therefore also can reduce the complexity of subsequent treatment module in the first step to a certain extent owing to be used to represent that the bit number of exporting related power also can reduce accordingly.But, handling the reduction of complexity, must be to be cost with certain performance sacrifice: as shown in Figure 8, and in order to reach 90% correct detection probability, " floating-point arithmetic " needs the Signal to Interference plus Noise Ratio of pact-7.5dB, uses the Signal to Interference plus Noise Ratio that method of the present invention then needs pact-6.0dB; Both compare, the mis-behave about 1.5dB of having an appointment between method provided by the invention and the optimal performance theoretically attainable(OPTA), and this can be regarded as the performance loss cost that has adopted low complex degree of the present invention " 1 bit " relevant apparatus.Similarly, under other a series of dissemination channel conditions, relevant simulation result (not providing here) has also shown similar mis-behave phenomenon.Mandatory declaration be, use the method for TD-SCDMA provided by the invention system search of initial zone, although compared a small amount of deterioration with theoretical optimum, under most conditions, its performance or acceptable, and can satisfy requirement of system design substantially.In fact, by the present invention further propose based on the method and apparatus that TD-SCDMA system first, second step of search of initial zone is carried out iterative processing, can remedy this performance loss preferably, this embodies obtaining in the relevant description to Fig. 9～13 below.
As shown in Figure 9, for applying the present invention to the flow chart of a kind of serial iteration method in TD-SCDMA system first, second step of search of initial zone.At first, in step 90, it is rapid to carry out initial cell search first step, has adopted synchronizer as shown in Figure 7 to realize that this step detects one or more SYNC-DL code word and sync bit thereof.Then, in step 91, carry out search of initial zone second step,, detect the Midamble code word in all corresponding code characters, and according to " reliability " of detects code word, generation " acceptance " or " refusal " indicates promptly according to the output in the step 90.Wherein, search of initial zone second step of described generation the " refusal " sign, can be based on being 03151479.0 as number of patent application, realizing of the method and apparatus that provided among the method and apparatus of middle guiding code sequence " in the TDS-CDMA system detect " (MIDAMBLE SEQUENCE DETECTION METHOD AND APPARATUS IN TD-SCDMASYSTEM) is provided name: this method and apparatus is by comparing the relevant output of other candidate Midamble code word in the relevant output group of maximum likelihood Midamble code word, can quantize to calculate " reliability " of the Midamble code word that detects, and by being worth with after a default threshold value compares, produce " acceptance " or " refusal " sign---that is, if detected Midamble code word has higher " reliability ", then search of initial zone second step produces one " acceptance " sign; Otherwise, will produce one " refusal " sign, this situation means two kinds of typical case: (1) channel circumstance at that time is abominable, and Signal to Interference plus Noise Ratio is crossed ratio; Perhaps rapid detected SYNC-DL code word of (2) initial cell search first step or corresponding frame synchronization position are wrong.Therefore, this search of initial zone second step method and device can judge whether continue to carry out subsequent step, and step re-executes before perhaps should returning, and perhaps should abandon search because signal quality is too poor.The flow chart of a kind of serial iteration method has as shown in Figure 9 reflected this consideration just.As shown in the figure, judge in step 92: if second step of the search of initial zone in the step 91 produces " acceptance " sign, this method stops, and will continue to carry out follow-up search of initial zone step, for example search of initial zone third step this moment; Otherwise,, then carry out next step 93 if second step of the search of initial zone in the step 91 produces " refusal " sign.In step 93, the number of times that search of initial zone second step is produced " refusal " sign increases by one, and will be worth with a default thresholding C compare (wherein C is a positive integer), if " refusal " number of times is no more than this thresholding, then return step 90, it is rapid to re-execute initial cell search first step, produces another batch SYNC-DL code word and does detection with corresponding frame synchronization position for search of initial zone second step; Otherwise, then stop this Cell searching, carry out subsequent operation, for example on next frequency, restart one time initial cell search procedure.Along with the increase of first, second step iteration execution number of times of search of initial zone, the correct probability that detects also can increase (seeing below the simulation result that literary composition provides); But, also should control the upper limit of iterations, search in the time of the frequency overspending of poor signal quality avoiding.Therefore, the selection of threshold value C should be taken all factors into consideration according to practical situations and design object; For TD-SCDMA system multi-frequency point search of initial zone scheme, the suggestion value of C is 1 here, that is allows the processing that repeats of first, second step of search of initial zone at most.
As shown in figure 10, be the schematic diagram of an example applying the present invention to a kind of serial iteration method in TD-SCDMA system first, second step of search of initial zone.At first in step 100, it is rapid to carry out initial cell search first step; Then, according to its SYNC-DL code word that provides and frame synchronization result, in step 101, carry out initial cell second step.In the example shown, search of initial zone second step has here produced " refusal " signal.According to the serial iteration method of first, second step of initial cell Cell searching of the present invention, subsequent to re-execute initial cell search first step in step 102 rapid.Then in step 103, according in step 102, producing SYNC-DL codeword detection result and corresponding frame synchronization output again, carry out search of initial zone second step again again---current search of initial zone second step of carrying out has been accepted detected Midamble code word.In this example, after having carried out the iterative processing of first, second step of search of initial zone, search of initial zone second step has produced " acceptance " sign, so iterative process finishes, to continue to carry out follow-up initial cell step, for example the search of initial zone third step carries out the synchronous of relevant multi-frame.
As shown in figure 11, for applying the present invention to the flow chart of a kind of simultaneous iteration in TD-SCDMA system first, second step of search of initial zone.Corresponding with the described a kind of serial iteration method that is applied in TD-SCDMA system first, second step of search of initial zone, also can be in iterative process first, second step of executed in parallel search of initial zone, to reach the purpose that under abominable channel circumstance, shortens first, second step spended time of initial cell.As shown in figure 11: at first, in step 110, it is rapid to carry out initial cell search first step, has adopted synchronizer as shown in Figure 7 to realize that this step detects one or more SYNC-DL code word and sync bit thereof.Then, in step 111, carry out search of initial zone second step, promptly according to the output in the first step in this iteration, detect the Midamble code word in all corresponding code characters, and, produce " acceptances " or " refusal " and indicate according to " reliability " of detection code word.Simultaneously, in this step 111, initial cell search first step also reruns suddenly simultaneously, produces another group SYNC-DL code word and sync bit thereof.Then, judge in step 112: if second step of the initial cell in the step 111 produces " acceptance " sign, this method stops, and will continue to carry out follow-up search of initial zone step, for example search of initial zone third step this moment; Otherwise,, then carry out next step 113 if produce " refusal " sign in step 2.In step 113, the number of times that search of initial zone second step is produced " refusal " sign increases by one, and will be worth with a default thresholding C compare (wherein C is a positive integer), if " refusal " number of times is no more than this thresholding, then return step 111, re-execute first, second step of search of initial zone---at this moment, search of initial zone second step should be carried out relevant the processing according to initial cell search first step in the preceding iteration rapid output SYNC-DL code word and corresponding frame synchronization position; Otherwise, then stop this Cell searching, will carry out subsequent operation, for example on next frequency, restart one time initial cell search procedure.In order to improve parallel efficiency, the time that should require first, second step of search of initial zone to be spent should try one's best approaching: for example, both all spend F frame, and wherein F is a positive integer.Compare with aforementioned a kind of serial iteration method, described simultaneous iteration is owing to carry out first, second step of initial cell simultaneously, so shortened search time,, compared at most with the serial iteration method and can save general approximately search time particularly under abominable channel circumstance; Certainly, its cost is the raising that the software/hardware disposal ability is required, because relevant design will provide the ability of carrying out first, second step of initial cell simultaneously.In addition, the selection of threshold value C in the described simultaneous iteration is consistent with relevant consideration in aforementioned a kind of serial iteration method.
As shown in figure 12, be the schematic diagram of an example applying the present invention to a kind of simultaneous iteration in TD-SCDMA system first, second step of search of initial zone.At first in step 120, it is rapid to carry out initial cell search first step; Then, according to its SYNC-DL code word that provides and frame synchronization result, in step 121, it is rapid to re-execute initial cell search first step; Simultaneously, search of initial zone second step according to a preceding iteration, be also executed in parallel of the rapid output SYNC-DL code word of initial cell search first step and frame synchronization position in the step 121.In the example shown, search of initial zone second step has here produced " refusal " signal.Simultaneous iteration according to first, second step of initial cell Cell searching of the present invention, subsequent first, second step of search of initial zone that re-executes in step 122, wherein search of initial zone second step is carried out according to the rapid output of initial cell search first step in the preceding iterative step 121.In the example shown, search of initial zone second step has here produced " refusal " signal once more.Because the C value is greater than 1, therefore do not withdraw from and still carry out next iteration, that is in step 123, re-execute first, second step of search of initial zone, wherein search of initial zone second step is carried out according to the rapid output of initial cell search first step in the preceding iterative step 122.In the example shown, current search of initial zone second step has produced " acceptance " sign finally, so iterative process finishes, will continue to carry out follow-up initial cell step, and for example the search of initial zone third step carries out the synchronous of relevant multi-frame.
As shown in figure 13, carry out the performance chart of TD-SCDMA system search of initial zone first and second steps for using serial iteration method of the present invention.Wherein, the relevant treatment in the initial cell first step has adopted " 1 bit " of the present invention correlation technique; Initial cell second step then is search of initial zone second step of a kind of generation the " refusal " sign that provided in the patent application 03151479.0.Simulation result has provided the simulation performance curve of corresponding 1～4 iterative processing.Channel condition is white Gaussian noise channel (AWGN).As seen from Figure 13, along with the increase of iterations, the correct detection probability index of gained is also improved constantly; Wherein, the performance boost amplitude maximum of iterations from 1 time to 2 times.Especially, the simulation performance curve of corresponding 2 iteration, the performance (with reference to figure 8) when having approached to adopt " floating-point " correlation technique.Therefore, adopt the alternative manner of TD-SCDMA provided by the invention system search of initial zone first and second steps, can remedy effectively because the performance loss of having adopted " 1 bit " relevant treatment of the low complex degree that the present invention proposes to bring.
By above-mentioned relevant explanation at Fig. 3～Figure 13 as seen, according to the present invention realize be used for TD-SCDMA system subscriber terminal equipment the method and apparatus that carries out search of initial zone, have relatively low relevant complexity and good performance, and can under more abominable propagation conditions, shorten the search of initial zone time in the TD-SCDMA system effectively.
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 the method and apparatus of the described in the invention a kind of TD-SCDMA of being applied to system search of initial zone 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 method and apparatus that is applied to the search of initial zone 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 (18)
1. the initial cell searching method in the TDS-CDMA system, it comprises:
Step 1: be applied to rapid " 1 bit " correlation step of initial cell search first step, this step 1 comprises:
1.1 extract road symbol step: according to the sampling input that receives data sync I road and quadrature Q road, the sign bit extractor extracts the sign bit { ai of I road and Q circuit-switched data respectively
n, aq
n;
Wherein subscript n is the input sample sequence number, and ai
nAnd aq
nRepresent the sign bit on I and the Q road respectively;
1.2 despining step: the despining device is to the I road and the Q road sign bit { ai of gained
n, aq
nCarry out the despining operation, obtain { bi
n, bq
n;
1.3 bit xor operation step: in n-hour, two groups of nearest 64 bit { bi that the shift register on I road and the Q road is received
N, bi
N-1..., bi
N-63And { bq
N, bq
N-1..., bq
N-63, by two batches of bit XOR unit, respectively with candidate SYNC-DL code word { s
1, s
2..., s
64Corresponding bit carry out the bit xor operation, obtain the two groups of XORs output { ui on I road and the Q road
1, ui
2..., ui
64And { uq
1, uq
2..., uq
64; S wherein
kValue be 0 or 1, subscript k=1,2 ..., 64;
1.4 statistics " 1 " number step: use " 1 " number counter to add up two groups of xor operation result { ui on I road and the Q road respectively
1, ui
2..., ui
64And { uq
1, uq
2..., uq
64In the number of " 1 ", obtain exporting ci and cq;
1.5 power calculation step:, calculate n-hour related power output p by power calculator according to input ci and cq value
N
2. the initial cell searching method in the TDS-CDMA system as claimed in claim 1 is characterized in that, in the described step 1.1, extracts sign bit and is undertaken by following relation:
If input＞=0, then output=1; Otherwise, output=0;
Perhaps,
If input＞=0, then output=0; Otherwise, output=1.
3. the initial cell searching method in the TDS-CDMA system as claimed in claim 1 or 2 is characterized in that, described bit despining operation can realize by exchange of I/Q road and bit inversion operation, that is:
bi
n＝ai
n，bq
n＝aq
n，n＝4k，k＝0，1，2，…
bi
n＝aq
n，bq
n＝~ai
n，n＝4k+1，k＝0，1，2，…
bi
n＝~ai
n，bq
n＝~aq
n，n＝4k+2，k＝0，1，2，…
bi
n＝~aq
n，bq
n＝ai
n，n＝4k+3，k＝0，1，2，…
Wherein, operator ~ x represents the inversion operation to bit x.
4. the initial cell searching method in the TDS-CDMA system as claimed in claim 1 or 2,
It is characterized in that in the step 1.3, described shift register receives two groups of nearest 64 bit { bi
N, bi
N-1..., bi
N-63And { bq
N, bq
N-1..., bq
N-63, be meant: will move into two 64 bit shift registers respectively through the I/Q road bit after the despining; Wherein, each 64 bit shift register has been preserved the sign bit of nearest 64 I or the sampling of Q circuit-switched data, when having new data sampling sign bit to enter, carries out a shifting function at every turn, the oldest sign bit shifted out abandon, and new data sampling sign bit is moved into.
5. the initial cell searching method in the TDS-CDMA system as claimed in claim 1 or 2,
It is characterized in that in the step 1.3, the bit xor operation on the I road is characterized by:
On the I road, respectively with bi
N+k-1Code word bits s with correspondence
kCarry out XOR, obtain output:
Ui
k=bi
N+1-k s
k, k=1,2 ..., 64, wherein, represents xor operation.
6. the initial cell searching method in the TDS-CDMA system as claimed in claim 5 is characterized in that, in the step 1.3, the bit xor operation on the Q road is characterized by:
On the Q road, respectively with bq
N+k-1Code word bits s with correspondence
kCarry out XOR, obtain output:
uq
k＝bq
N+1-ks
k，k＝1，2，…，64。
7. the initial cell searching method in the TDS-CDMA system as claimed in claim 4 is characterized in that step 1.4 is characterized by with formula:
ci＝ui
1+ui
2+…+ui
64
cq＝uq
1+uq
2+…+uq
64。
8. the initial cell searching method in the TDS-CDMA system as claimed in claim 7 is characterized in that, ci and cq value are in [0,64] scope.
9. the initial cell searching method in the TDS-CDMA system as claimed in claim 5 is characterized in that step 1.5 is characterized by with formula:
p
N＝(32-ci)
2+(32-cq)
2。
10. the initial cell searching method in the TDS-CDMA system as claimed in claim 1 is characterized in that, also comprises rapid, the second step serial iteration step of initial cell search first step, and this step comprises:
2.1 rapid corresponding to initial cell search first step, carry out initial cell search first step rapid after, detect one or more SYNC-DL code word and sync bit thereof;
2.2 corresponding to search of initial zone second step, according to the output in the step 2.1, detect in all corresponding code characters in lead a yard code word, and, produce " acceptances " or " refusal " and indicate according to " reliability " of detection code word;
2.3 if step 2.2 produces " acceptance " sign, then continue to carry out follow-up search of initial zone step; Otherwise if step 2.2 produces " refusal " sign, then execution in step 2.4;
Increase by one 2.4 search of initial zone second step is produced the number of times of " refusal " sign, and the value and a default thresholding C that will be somebody's turn to do " refusal " number of times compare, this C value is a positive integer, if " refusal " number of times is no more than this thresholding, then return step 2.1, re-execute the initial cell first step; Otherwise, then stop this Cell searching, carry out subsequent operation.
11. the initial cell searching method in the TDS-CDMA system as claimed in claim 1 is characterized in that, also comprises rapid, the second step parallel iteration step of initial cell search first step, this parallel iteration step comprises:
3.1 rapid corresponding to initial cell search first step, carry out initial cell search first step rapid after, detect one or more SYNC-DL code word and sync bit thereof;
3.2 executed in parallel corresponding to first and second step of search of initial zone, on the one hand, search of initial zone second step is the output in rapid according to a preceding initial cell search first step, detect in the corresponding code character in lead a yard code word, and, produce " acceptances " or " refusal " and indicate according to " reliability " of detection code word; On the other hand, initial cell search first step reruns suddenly, produces another group SYNC-DL code word and sync bit thereof;
3.3 if step 3.2 produces " acceptance " sign, then continue to carry out follow-up search of initial zone step; Otherwise if step 3.2 produces " refusal " sign, then execution in step 3.4;
Increase by one 3.4 search of initial zone second step is produced the number of times of " refusal " sign, and will be worth with a default thresholding C and compare, this C value is a positive integer, is no more than this thresholding as if " refusal " number of times, then return step 3.2, re-execute first, second step of initial cell; Otherwise, then stop this Cell searching, carry out subsequent operation.
12. the search of initial zone device in the TDS-CDMA system, it comprises: 1 or some " 1 bit " sub-relevant apparatus, the input separately that is somebody's turn to do " 1 bit " sub-relevant apparatus connects the sampled data output, is characterised in that, should comprise by " 1 bit " sub-relevant apparatus:
The sign bit extractor receives the sampled data input from I branch road, Q branch road, and extracts the sign bit of I road and Q circuit-switched data;
With the despining device that this sign bit extractor signal is connected, its I road and Q road sign bit to gained carries out the despining operation;
The shift register that is connected with the despining device receives nearest 64 bits from I road and Q road;
Two batches of bit XOR unit, these two batches of bit XOR unit connect shift registers and candidate SYNC-DL code word interface, and will above-mentioned 64 bits recently respectively with candidate SYNC-DL code word { s
1, s
2..., s
64Corresponding bit carry out the bit xor operation;
Two " 1 " number counters, these two " 1 " number counters are connected with the output port of above-mentioned two batches of bit XOR unit respectively, add up on the I/Q road number of " 1 " among two groups of xor operation results respectively, obtain exporting ci and cq;
With described two power calculators that " 1 " number counter is connected, it calculates n-hour related power output p according to above-mentioned output
N
13. the search of initial zone device in the TDS-CDMA system as claimed in claim 12 is characterized in that, described sign bit extractor comprises the symbol extraction device of 2 parallel connections, extracts the sign bit of I road, Q circuit-switched data respectively.
14. the search of initial zone device as in claim 12 or the 13 described TDS-CDMA system is characterized in that, described despining device has comprised I/Q road switched circuit and bit negate circuit.
15. the search of initial zone device as in claim 12 or the 13 described TDS-CDMA system is characterized in that described shift register comprises the shift register of 2 parallel connections, they receive nearest 64 bits from I road and Q road respectively.
16. as the search of initial zone device in claim 12 or the 13 described TDS-CDMA system, it is characterized in that, described shift register receives two groups of nearest 64 bits, is meant: will move into this two 64 bit shift registers respectively through I road after the despining and Q road bit; Wherein, each 64 bit shift register has been preserved the sign bit of nearest 64 I or the sampling of Q circuit-switched data, when having new data sampling sign bit to enter, carries out a shifting function at every turn, the oldest sign bit shifted out abandon, and new data sampling sign bit is moved into.
17. the search of initial zone device as in claim 12 or the 13 described TDS-CDMA system is characterized in that described power calculator comprises some squarers and some adding/subtracter.
18. as the search of initial zone device in claim 12 or the 13 described TDS-CDMA system, it is characterized in that, described power calculator comprises table look-up logical block and adder, and the wherein said logical block of tabling look-up is used to realize function f (x)=(32-x)
2, wherein the span of integer x is [0,64].
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| CN100377504C (en) * | 2005-07-14 | 2008-03-26 | 凯明信息科技股份有限公司 | First-step search of initial zone in time division synchronizing CDMA system |
| CN101247625B (en) * | 2007-02-12 | 2012-04-25 | 华为技术有限公司 | Terminal access method and apparatus under time-sharing channel structure |
| CN101299839B (en) * | 2007-04-30 | 2012-05-30 | 华为技术有限公司 | Method and apparatus for resource allocation and terminal access in time-division sharing channel |
| CN101572590B (en) * | 2008-05-04 | 2013-02-27 | 中兴通讯股份有限公司 | Method for sending frame control message |
| CN101854714B (en) * | 2010-05-13 | 2012-09-05 | 清华大学 | Method for achieving wireless communication timing coarse synchronization by using 1bit quantification and hard decision |
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| CN1292611A (en) * | 1999-07-05 | 2001-04-25 | 松下电器产业株式会社 | Communication terminal device and basic station device |
| WO2001074103A1 (en) * | 2000-03-27 | 2001-10-04 | China Academy Of Telecommunications Technology | Method of cell initial search in cdma digital mobile telecommunication system |
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| WO2003063538A1 (en) * | 2002-01-21 | 2003-07-31 | Siemens Mobile Communications S.P.A. | Method and mobile station to perform the initial cell search in time slotted systems |
| CN1505292A (en) * | 2002-12-02 | 2004-06-16 | 北京三星通信技术研究有限公司 | Method of time synchronization detection and time synchronization for orthogonal frequency division multiplexing communication system |
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| CN1292611A (en) * | 1999-07-05 | 2001-04-25 | 松下电器产业株式会社 | Communication terminal device and basic station device |
| WO2001074103A1 (en) * | 2000-03-27 | 2001-10-04 | China Academy Of Telecommunications Technology | Method of cell initial search in cdma digital mobile telecommunication system |
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