CN100508428C - A method and apparatus for increasing synchronous detection precision - Google Patents

Abstract

The invention is a method and device for improving synchronous detecting precision, used in synchronous detection based on ascending time gap in CDMA system, and its method includes the steps: antenna data segment obtaining to determine the data segment where the synchronous code exists; matching filtration: for detecting if there is ascending synchronous access at protective intervals and ascending guide frequency time gap intervals, firstly making shift relation between NSYNC_UL ascending synchronous codes and with antenna received data at protective intervals and ascending guide frequency time gas intervals and obtaining related power sequence; signature identification: detecting and judging the total related frequency sequence and only in the situation of meeting preset detecting conditions can it determine there is ascending synchronous access; fast physical access channel arrangement: making priority processing according to many ascending synchronous signatures in each subframe. It gives a multiple sampling-based method and device fro improving synchronous detecting precision, improving the synchronous detecting precision.

Description

A kind of method and apparatus that improves synchronous detecting precision

Technical field

The present invention relates to the method and apparatus that a kind of wireless communication system inserts at random, relate in particular in the code division multiple address communication system method and apparatus based on the synchronous detecting of uplink pilot time slot.

Background technology

At synchronization CDMA (Code Division Multiple Access, code division multiple access) in the up link of communication system, a plurality of user terminal UE (User Equipment) send signal to base station (Node B), in order to prevent the phase mutual interference between the different user signal, need carry out synchronous detecting and control to each user, guarantee that it arrives the base station simultaneously.

The radio frames of synchronous CDMA communications system comprises some subframes; in each subframe except a plurality of conventional time slots; also comprise 3 special time slots; be descending pilot frequency time slot (DwPTS), protection (GP) time slot and uplink pilot time slot (UpPTS) at interval; wherein UpPTS is ascending pilot frequency and design synchronously, yard is made up of at interval with the protection of this time slot inside uplink synchronous (SYNC_UL).

In synchronous CDMA communications system, what insert at random that synchronous detecting refers to is exactly the process of setting up of uplink synchronous.After user terminal UE start, must at first set up down-going synchronous with the sub-district.Only under the condition of down-going synchronous, could begin to set up uplink synchronous.

Being based upon in the random access procedure of uplink synchronous finished, and relates to ascending pilot channel (UpPCH) and Physical Random Access Channel (PRACH).User terminal UE is when inserting at random, at first in uplink pilot time slot (UpPTS), send uplink synchronous (SYNC_UL) sign indicating number, if base station node B can successfully detect this SYNC_UL sign indicating number, then the physical access channel (FPACH) in descending correspondence goes up to user terminal UE transmission acknowledge message, user terminal UE can go up to base station node B at the Physical Random Access Channel of distributing (PRACH) and send access information then, last base station node B sends to user terminal UE with the information of necessity again, and call setup is finished.

Detect the SYNC_UL sequence in search window after, base station node B estimates corresponding time delay, answers user terminal UE by sending adjustment information then, makes user's terminal UE adjust launch time when launching next time.This finishes in ensuing several subframes by FPACH.Sent after the PRACH, uplink synchronous is set up.Uplink synchronous when the uplink synchronous process also can be used for uplink loss rebulids.

Synchronous detecting is discerned the SYNC_UL sign indicating number by the antenna data of analyzing protection interval and uplink pilot time slot.If detect an effective SYNC_UL sign indicating number, then finish relevant parameters and measure task.

In following document, introduced prior art about synchronous detecting:

[1] patent " Synchronization detection circuit for radio communication; has matched filter to output correlation val UE between spreading code anddata obtained by sampling spread signal using one-chip cycle samplingclock ". United States Patent (USP), publication number: US 20030152138, the open date: on August 14th, 2003; Japan Patent, publication number: JP 2003234677, open date: on August 22nd, 2003; Chinese patent, publication number: CN 1437323, open date: on August 20th, 2003

[2] patent " Synchronization detecting apparatus has synchronizationdetector which detects synchronization using demodulated synchronizationsignal depending on channel estimation result using pilot signal ". United States Patent (USP), publication number: US 20020093988, the open date: on July 18th, 2002; Japan Patent, publication number: JP 2002217775, open date: on August 2nd, 2002

[3] patent " is caught a kind of method and apparatus of Random Access Channel preamble " in the WCDMA system. Chinese patent, and publication number: 1389995, the open date: on January 8th, 2003

[4] Zhou Haijun, Yan Xiaoli, Xiong Simin, Xie Xianzhong. " the access performance analysis at random of TD-SCDMA system ". Post and Telecommunications Institutes Of Chongqing's journal, the 14th the 4th phase of volume, in December, 2002, the 19th～23 page

In existing technology, synchronization detection process is based on single-time sampling, i.e. the only corresponding sampled point of a chip (chip).Like this, then bigger if sampled point departs from the output peak value of root raised cosine filter to the Signal to Interference plus Noise Ratio influence that receives data, thus the synchronous detecting performance is reduced.

Summary of the invention

Purpose of the present invention promptly is at the existing problem of above-mentioned single-time sampling, a kind of method and apparatus that improves synchronous detecting precision is provided, in order to overcome the shortcoming of single-time sampling in the synchronous CDMA communications system random access procedure, solve the synchronous detecting precision problem that exists in the prior art, utilize uplink synchronous (SYNC_UL) sign indicating number in the uplink pilot time slot (UpPTS), provide a kind of method and apparatus of the raising synchronous detecting precision based on multiple sampling, thereby improved the performance of synchronous detecting.

Technical scheme of the present invention is as follows:

A kind of method that improves synchronous detecting precision is used for the synchronous detecting of code division multiple address communication system based on uplink pilot time slot, and it may further comprise the steps:

A) antenna data segment is obtained, in order to determine the data segment at uplink synchronous code place;

B) matched filtering: with the N of current area _{SYNC_UL}Individual uplink synchronous code respectively with protection at interval and the reception of the antenna on uplink pilot time slot interval data be shifted relevantly, obtain the related power sequence;

C) signature identification, in order to the total correlation power sequence is detected judgement, under the situation that satisfies the predetermined detection condition, just judging has uplink synchronous to insert;

D) physical access channel arrangement in every subframe, is carried out processed according to the rank of a plurality of uplink synchronous signatures.

Described method, wherein, described step a) also comprises: detection window comprises protection interval and uplink pilot time slot, and described data segment comprises L _DataIndividual chip, comprising protecting at interval and the number of chips summation of uplink pilot time slot, length is L _Data* SR sampled point, SR are sample rate, i.e. the sampling number of a chip.

Described method, wherein, described sample rate SR value is 2,4,8.

Described method, wherein, described step b) also comprises the following steps:

B1) the real number uplink synchronous code is carried out the plural number processing, i.e. employed plural uplink synchronous code in the system $\underset{\&OverBar;}{s}=({\underset{\&OverBar;}{s}}_1,{\underset{\&OverBar;}{s}}_2,...,{\underset{\&OverBar;}{s}}_{L_{\mathrm{sync}\_\mathrm{ul}}})$ Can be by the real number uplink synchronous code $s=({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="C200410027884E00221.png"\; state="\{\{state\}\}">s</figure-callout>}}_1,s_2,...,s_{L_{\mathrm{sync}\_\mathrm{ul}}})$ Obtain, promptly

s _i＝j ⁱ·s _i s _i∈{1，-1}，i＝1，2，...，L _{sync_ul}

(1)

L in the formula _{SYNC_UL}The length of expression SYNC_UL sign indicating number;

B2) correlated series of calculating uplink synchronous code and antenna data, the correlated series of each antenna is expressed as

$R^{\left(\mathrm{ka}\right)}=\underset{k,n}{\mathrm{\&Sigma;}}{r}_n^{\left(\mathrm{ka}\right)}\&CenterDot;{\left({\underset{\&OverBar;}{s}}_{k+i}\right)}^{*}---\left(2\right)$

In the formula

The reception data of representing Ka antenna, () ^*The expression conjugate operation, subscript Ka represents the antenna sequence number, Ka=0,1 ..., Ka-1, Ka are antenna number;

B3) calculate the related power sequence of each antenna correspondence, promptly

$R_P^{\left(\mathrm{ka}\right)}={\left(\mathrm{Re}\right[R^{\left(\mathrm{ka}\right)}\left]\right)}^2+{\left(\mathrm{Im}\right[R^{\left(\mathrm{ka}\right)}\left]\right)}^2---\left(3\right)$

Re[in the formula] expression gets real part computing, Im[] expression gets imaginary-part operation.

Described method, wherein, described step c) comprises the following steps:

C1) the total correlation power sequence calculates, and the related power sequence addition of each antenna obtains the total correlation power sequence, promptly

$R_{\mathrm{Power}}=\underset{\mathrm{ka}=0}{\overset{\mathrm{Ka}-1}{\mathrm{\&Sigma;}}}{R}_P^{\left(\mathrm{ka}\right)}---\left(4\right)$

Ka is an antenna number in the formula, and subscript ka represents the antenna sequence number.

C2) peak value detects, at total correlation power sequence R _PowerIn search maximum power value P_peak and corresponding peak value position Po_peak thereof, define a signal peak window, this window is included peak, window length is

T;

Leading window of definition before peak value window, window is long to be W ₁

Lag windwo of definition after peak value window, window is long to be W ₂

The function that peak value detects is to be used for difference between maximum power value and leading, that lag windwo the is interior average power in the detection peak window, if the difference between the average power in maximum power value and leading, the lag windwo is greater than a certain threshold value, then the peak value testing conditions is set up;

C3) collision detection, at first to the uplink synchronous identification of signing, whether the detection peak window exists other higher total correlation power peak outward then, if its value is lower than given parameter, then can thinks access interference does not take place, and the uplink synchronous signature is effectively; The end position of collision detection window width from signal peak window starting position to the total correlation power sequence; If detect access interference, then the base station does not send response physical access channel (FPACH).

Described method, wherein, described step d) comprises that also all uplink synchronous signatures are kept in the formation in order, and each subframe all responds the signature of specific quantity, and Xiang Ying signature does not then continue to be kept in the formation, and its comparative lifetime adds 1; The initial value of each signature comparative lifetime is 0, and the rule of response of signature is as follows:

D1) at first select the reliable signature of comparative lifetime maximum;

D2) if there is not reliable signature, then select prominent normal signature;

If exist a plurality of signatures to satisfy above-mentioned rule, then optional signature responds, and after the response, this signature is promptly deleted from formation, and the comparative lifetime of each signature can not surpass a certain specified threshold in the formation, otherwise with deleted.

A kind of device that improves synchronous detecting precision, it comprises following a few part:

One signal receiving device (101), be connected with antenna, convert digital baseband signal to after the processing such as the amplification of wireless signal this signal receiving device of process (101) that this antenna receives, filtering, down-conversion, analog to digital conversion, wherein sample rate is selected in analog to digital conversion;

One matched filter (102), and local uplink synchronous code generating apparatus (103), this this locality uplink synchronous code generating apparatus (103) produces the N that adopt this sub-district _{SYNC_UL}Individual uplink synchronous code; Described matched filter (102) is then used this N _{SYNC_UL}Individual uplink synchronous code respectively with protection at interval and each antenna data on the uplink pilot time slot interval be shifted relevantly, and obtain the related power sequence of each antenna;

One signature recognition device (104), this signature recognition device (104) is at first with the related power sequence addition of each antenna, obtain the total correlation power sequence, then the total correlation power sequence being carried out peak value respectively detects and collision detection, thereby determine whether to exist effective uplink synchronous signature, promptly the user inserts;

One physical access channel arrangement (105), this physical access channel arrangement (105) responds the uplink synchronous signature in order successively according to the priority level of signature, promptly distributes corresponding physical access channel channel.

A kind of method and apparatus that improves synchronous detecting precision provided by the present invention, owing to adopt uplink synchronous (SYNC_UL) sign indicating number that utilizes in the uplink pilot time slot (UpPTS), provided a kind of method and apparatus of the raising synchronous detecting precision based on multiple sampling, thereby improved the performance of synchronous detecting, improved the precision of synchronous detecting.

Description of drawings

To elaborate to the specific embodiment of the invention by reference with in conjunction with each accompanying drawing of following the present invention, so that purpose of the present invention, technical scheme and advantage are clearer, easy to understand, in the accompanying drawing:

Fig. 1 is the schematic diagram of physical channel wireless frame structure in the synchronous CDMA communications system of the inventive method;

Fig. 2 is the schematic diagram of uplink pilot time slot (UpPTS) structure of the inventive method;

Fig. 3 is the schematic diagram of peak value testing conditions during the synchronous detecting signature of the inventive method is discerned;

Fig. 4 is the schematic diagram of collision detection condition during the synchronous detecting signature of the inventive method is discerned;

Fig. 5 is the sync detection device structured flowchart of apparatus of the present invention.

Embodiment

Be described in further detail below in conjunction with the enforcement of accompanying drawing technical scheme:

The device of raising synchronous detecting precision of the present invention consists of the following components:

A. signal receiving device (101)

B. matched filter (102)

C. local uplink synchronous (SYNC_UL) sign indicating number generating apparatus (103)

D. the recognition device (104) of signing

E. physical access channel (FPACH) arrangement (105)

Convert digital baseband signal to after the processing such as the amplification of the wireless signal process signal receiving device (101) that antenna receives, filtering, down-conversion, analog to digital conversion, wherein sample rate is selected in analog to digital conversion; The function of local uplink synchronous (SYNC_UL) sign indicating number generating apparatus (103) is to produce the N that adopt this sub-district _{SYNC_UL}Individual SYNC_UL sign indicating number; Matched filter (102) is then used this N _{SYNC_UL}Individual SYNC_UL sign indicating number respectively with protection at interval and each antenna data on the uplink pilot time slot interval be shifted relevantly, and obtain the related power sequence of each antenna; Signature recognition device (104) is at first with the related power sequence addition of each antenna, obtain the total correlation power sequence, then the total correlation power sequence is carried out peak value respectively and detect and collision detection, thereby determine whether to exist effective SYNC_UL signature (user's access); Physical access channel (FPACH) arrangement (105) responds the SYNC_UL signature in order successively according to the priority level of signature, promptly distributes corresponding FPACH channel.

The method of raising synchronous detecting precision of the present invention is as follows:

The first step, antenna data segment is obtained

This step is used for determining the data segment at uplink synchronous (SYNC_UL) place, and detection window comprises protection (GP) and uplink pilot time slot (UpPTS) at interval, and data segment comprises L _DataIndividual chip comprises promptly and protecting at interval and the number of chips summation of uplink pilot time slot that length is L _Data* SR sampled point, SR are sample rate, i.e. the sampling number of a chip.The synchronization accuracy of considering synchronous CDMA communications system is generally 1/8 chip, then SR desirable 1,2,4,8, the situation of SR=1 is existing Synchronous Detection based on single-time sampling, and SR=2,4,8 situation then are the Synchronous Detection based on multiple sampling proposed by the invention.The SR value is big more, and then synchronous detecting precision is high more, but computation complexity and memory data output are also big more, so choosing of SR value be decided according to actual conditions.

Second step, matched filtering

Whether there to be SYNC_UL to insert in order detecting on protection interval and uplink pilot time slot interval, at first to need N with current area _{SYNC_UL}Individual SYNC_UL sign indicating number respectively with protection at interval and the reception of the antenna on uplink pilot time slot interval data be shifted relevantly, obtain the related power sequence.

Matched filtering can comprise the following steps:

1. real number SYNC_UL sign indicating number is carried out the plural number processing, i.e. employed plural SYNC_UL sign indicating number in the system $\underset{\&OverBar;}{s}=({\underset{\&OverBar;}{s}}_1,{\underset{\&OverBar;}{s}}_2,...,{\underset{\&OverBar;}{s}}_{L_{\mathrm{sync}\_\mathrm{ul}}})$ Can be by real number SYNC_UL sign indicating number

$s=({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="C200410027884E00221.png"\; state="\{\{state\}\}">s</figure-callout>}}_1,s_2,...,s_{L_{\mathrm{sync}\_\mathrm{ul}}})$ Obtain, promptly

s _i＝j ⁱ·s _i s _i∈{1，-1}，i＝1，2，...，L _{sync_ul} (1)

L in the formula _{SYNC_UL}The length of expression SYNC_UL sign indicating number.

2. calculate the correlated series of SYNC_UL sign indicating number and antenna data.The correlated series of each antenna is expressed as

$R^{\left(\mathrm{ka}\right)}=\underset{k,n}{\mathrm{\&Sigma;}}{r}_n^{\left(\mathrm{ka}\right)}\&CenterDot;{\left({\underset{\&OverBar;}{s}}_{k+i}\right)}^{*}---\left(2\right)$

In the formula

The reception data of representing ka antenna, () ^*The expression conjugate operation, subscript ka represents the antenna sequence number, ka=0,1 ..., KA-1, Ka are antenna number.

3. calculate the related power sequence of each antenna correspondence, promptly

$R_P^{\left(\mathrm{ka}\right)}={\left(\mathrm{Re}\right[R^{\left(\mathrm{ka}\right)}\left]\right)}^2+{\left(\mathrm{Im}\right[R^{\left(\mathrm{ka}\right)}\left]\right)}^2---\left(3\right)$

Re[in the formula] expression gets real part computing, Im[] expression gets imaginary-part operation.

The 3rd step, signature identification (Signature Identification)

This step can comprise the following steps: again

1. the total correlation power sequence calculates

The related power sequence addition of each antenna obtains the total correlation power sequence, promptly

$R_{\mathrm{Power}}=\underset{\mathrm{ka}=0}{\overset{\mathrm{Ka}-1}{\mathrm{\&Sigma;}}}{R}_P^{\left(\mathrm{ka}\right)}---\left(4\right)$

Ka is an antenna number in the formula, and subscript ka represents the antenna sequence number.

Signature identification detects judgement to the total correlation power sequence exactly, and under the situation that described below testing conditions satisfies, just judging has SYNC_UL to insert.

2. peak value detects

At total correlation power sequence R _PowerIn search maximum power value (peak-peak) P_peak and corresponding peak value position Po_peak thereof.

Define a signal peak window (peak window), this window is included peak, and window length is

A definition leading window (pre-window) before peak value window, window is long to be W ₁

A definition lag windwo (post-window) after peak value window, window is long to be W ₂

The function that peak value detects is to be used for difference between maximum power value and leading, that lag windwo the is interior average power in the detection peak window, if the difference between the average power in maximum power value and leading, the lag windwo is greater than a certain threshold value, then the peak value testing conditions is set up.

3. collision detection

When having only a user to insert, the total correlation power in the peak value window is very high, and the total correlation power outside the peak value window is very low.If when existing a plurality of users to insert, outside peak value window, also has higher total correlation power so.Therefore at first need the identification of signing to SYNC_UL, whether the detection peak window exists other higher total correlation power peak outward then, if its value is lower than given parameter, then can thinks access interference (collision) does not take place, and SYNC_UL signs effective.The end position of collision detection window width from signal peak window starting position to the total correlation power sequence.

When considering up access, two user terminal UE have used identical SYNC_UL sign indicating number, access interference will occur like this.If detect access interference, then base station node B does not send response physical access channel (FPACH).

In the 4th step, physical access channel (FPACH) is arranged

In every subframe, may detect a plurality of SYNC_UL signatures, and the FPACH number that every subframe disposed in the sub-district may be less than detected number of signature, therefore need carry out processed according to the rank of signature.

All SYNC_UL signatures are kept in the formation in order, and each subframe all responds the signature of specific quantity, and Xiang Ying signature does not then continue to be kept in the formation, and its " comparative lifetime " adds 1.The initial value of each signature " comparative lifetime " is 0.The rule of response of signature is as follows:

1. at first select " comparative lifetime " maximum reliable signature;

2. if there is not reliable signature, then select prominent normal signature.

If exist a plurality of signatures to satisfy above-mentioned rule, then optional signature responds.After the response, this signature is promptly deleted from formation." comparative lifetime " of each signature can not surpass a certain specified threshold in the formation, otherwise with deleted.

The radio frames of synchronous CDMA communications system comprises some subframes; in each subframe except a plurality of conventional time slots; also comprise 3 special time slots; be descending pilot frequency time slot (DwPTS), protection (GP) time slot and uplink pilot time slot (UpPTS) at interval; wherein uplink pilot time slot is ascending pilot frequency and design synchronously, yard is made up of at interval with the protection of this time slot inside uplink synchronous (SYNC_UL).As depicted in figs. 1 and 2.

Concrete, the method step of raising synchronous detecting precision of the present invention is as follows:

The first step, antenna data segment is obtained

This step is used for determining the data segment at uplink synchronous (SYNC_UL) place, and detection window comprises protection (GP) and uplink pilot time slot (UpPTS) at interval, and data segment comprises L _DataIndividual chip (the number of chips summation that promptly comprises protection interval and uplink pilot time slot), length is L _Data* SR sampled point, SR are sample rate, i.e. the sampling number of a chip.The synchronization accuracy of considering synchronous CDMA communications system is generally 1/8 chip, and then SR desirable 1,2,4,8.The situation of SR=1 is existing Synchronous Detection based on single-time sampling.SR=2,4,8 situation then are the Synchronous Detection based on multiple sampling proposed by the invention.The SR value is big more, and then synchronous detecting precision is high more, but computation complexity and memory data output are also big more, so choosing of SR value be decided according to actual conditions.

The data segment that obtains is expressed as

N=0,1 ..., L _Data* SR-1.

Each element be plural number, subscript ka represents the antenna sequence number, ka=0,1 ..., Ka-1, Ka are antenna number.

Second step, matched filtering

Whether there to be SYNC_UL to insert in order detecting on protection interval and uplink pilot time slot interval, at first to need N with current area _{SYNC_UL}Individual SYNC_UL sign indicating number respectively with protection at interval and the reception of the antenna on uplink pilot time slot interval data be shifted relevantly, obtain the related power sequence.

The effect of matched filtering is SYNC_UL sign indicating number and the antenna data of calculation base station (Node B)

I=0,1 ..., L _DataThe correlation of * SR-1.

The length of SYNC_UL sign indicating number is L _{SYNC_UL}Individual chip, at SR sampling situation, then must be with L _{SYNC_UL}The real number SYNC_UL sign indicating number of individual chip

I=0,1 ..., L _{Sync_ul}-1 converts the L of SR sampling correspondence to _{SYNC_UL}The real number SYNC_UL sign indicating number that * SR is ordered

K=0,1 ..., L _{Sync_ul}* SR-1, promptly

(5)

Wherein subscript sync represents SYNC_UL sign indicating number sequence number, sync=0, and 1 ..., N _{Sync_ul}-1 (each sub-district comprises N _{SYNC_UL}Individual SYNC_UL sign indicating number).

The related operation result of the data of sync SYNC_UL sign indicating number and ka antenna is expressed as I=0,1 ..., (L _{Sync_ul}+ L _Data) * SR-1, corresponding related power sequence table is shown

I=0,1 ..., (L _{Sync_ul}+ L _Data) * SR-1, wherein the related operation length of SR sampling situation is (L _{SYNC_UL}+ L _Data) * SR.Usually get L _{Sync_ul}≤ L _Data≤ 2L _{Sync_ul}

Matched filtering can comprise following concrete steps:

1. real number SYNC_UL sign indicating number is carried out the plural number processing, promptly

$\mathrm{Sync}\_{\mathrm{code}}_k^{\left(\mathrm{sync}\right)}=R\_\mathrm{sync}\_{\mathrm{code}}_k^{\left(\mathrm{sync}\right)}\&times;{\left(j\right)}^{m+1}---\left(6\right)$

In the formula

Expression is rounding operation down, (j) ^M+1Be equivalent to the plural number processing of uplink synchronous code.

2. calculate the correlated series of SYNC_UL sign indicating number and antenna data, promptly

$\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\underset{k,n}{\mathrm{\&Sigma;}}\mathrm{Rx}\_{\mathrm{sync}}_n^{\left(\mathrm{ka}\right)}\&CenterDot;{(\mathrm{Sync}\_{\mathrm{code}}_{k+i}^{\left(\mathrm{sync}\right)})}^{*}$

i＝0，1，…，(L _{sync_ul}+L _data)×SR-1 (8)

k＝0，1，…，L _{sync_ul}×SR-1

n＝0，1，…，L _data×SR-1

3. calculate the related power sequence of each antenna correspondence, promptly

$\mathrm{Rx}\_{\mathrm{pow}}_i^{(\mathrm{ka},\mathrm{sync})}={\left(\mathrm{Re}\right[\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}\left]\right)}^2+{\left(\mathrm{Im}\right[\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}\left]\right)}^2---\left(9\right)$

Re[in the formula] expression gets real part computing, Im[] expression gets imaginary-part operation.

In engineering was used, in order to reduce computation complexity, related operation can adopt fast fourier transform/inverse transformation (FFT/IFFT) method to realize, wherein FFT/IFFT all is FFT/IFFT of plural number.As mentioned above, antenna data length is L _Data* SR, so the figure place of FFT/IFFT adopts L _Data* SR.

In order to calculate L _DataThe convenience of * SR position FFT/IFFT can be at the L of SR sampling correspondence _{SYNC_UL}The plural SYNC_UL sign indicating number of * SR point

(L is added in the back _Data-L _{Sync_ul}) * SR position " 0 ", polishing is to L _Data* SR position.Usually get L _{Sync_ul}≤ L _Data≤ 2L _{Sync_ul}

Particularly, with L _Data=2L _{Syc_ul}Be example, adopt the FFT/IFFT method to realize that the step of related operation is as follows:

①

②

③

④ $\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{bef}}_i^{(\mathrm{ka},\mathrm{sync})}{|}_{i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,L_{\mathrm{data}}\&times;\mathrm{SR}-1}=\mathrm{IFFT}\left[\mathrm{FFT}\right[\mathrm{Rx}\_\mathrm{data}\_\mathrm{be}{f}^{\left(\mathrm{ka}\right)}]$

FFT[in the formula] the expression fast fourier transform, IFFT[] the expression invert fast fourier transformation.

⑤ $\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{aft}}_i^{(\mathrm{ka},\mathrm{sync})}{|}_{i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,L_{\mathrm{data}}\&times;\mathrm{SR}-1}=\mathrm{IFFT}\left[\mathrm{FFT}\right[\mathrm{Rx}\_\mathrm{data}\_a{\mathrm{ft}}^{\left(\mathrm{ka}\right)}]$

$\&CenterDot;\mathrm{FFT}[\mathrm{Inv}\_\mathrm{sync}\_{\mathrm{code}}^{\left(\mathrm{sync}\right)}]]---\left(14\right)$

⑥ $\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{bef}}_n^{(\mathrm{ka},\mathrm{sync})}---\left(15\right)$

i＝0，1，…，L _{sync_ul}×SR-1，n＝0，1，…，L _{sync_ul}×SR-1

⑦ $\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{bef}}_n^{(\mathrm{ka},\mathrm{sync})}+\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{aft}}_n^{(\mathrm{ka},\mathrm{sync})}---\left(16\right)$

i＝(L _data-L _{sync_ul})×SR，…，L _data×SR-1

n＝(L _data-L _{sync_ul})×SR，…，L _data×SR-1

⑧ $\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{aft}}_n^{(\mathrm{ka},\mathrm{sync})}---\left(17\right)$

i＝L _data×SR，…，(L _{sync_ul}+L _data)×SR-1

n＝0，1，…，L _{sync_ul}×SR-1

More preferably, N that adopt the sub-district _{SYNC_UL}Individual SYNC_UL sign indicating number determines, therefore when utilizing the FFT/IFFT method to carry out related operation, can be in advance the FFT result of SYNC_UL sign indicating number be calculated, and promptly precomputes FFT[Inv_sync_code ^(sync)], and be stored on the memory device, directly call during in order to related operation, thereby further reduce computation complexity.

The 3rd step, signature identification (Signature Identification)

This step can comprise the following steps: again

1. the total correlation power sequence calculates

The related power sequence addition of each antenna gets the total correlation power sequence, promptly

$\mathrm{Rx}\_{\mathrm{power}}_i^{\left(\mathrm{sync}\right)}=\underset{\mathrm{ka}=0}{\overset{\mathrm{Ka}-1}{\mathrm{\&Sigma;}}}\mathrm{Rx}\_{\mathrm{pow}}_i^{(\mathrm{ka},\mathrm{sync})},i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,(L_{\mathrm{sync}\_\mathrm{ul}}+L_{\mathrm{data}})\&times;\mathrm{SR}-1---\left(18\right)$

Ka is an antenna number in the formula, and subscript ka represents the antenna sequence number, and subscript sync represents SYNC_UL sign indicating number sequence number.

Signature identification detects judgement to the total correlation power sequence exactly, and under the situation that described below testing conditions satisfies, just judging has SYNC_UL to insert.

2. peak value detects

As shown in Figure 3.

Peak value testing conditions: P_peak-max[P_aver_befo, P_aver_afte] Pd (dB)

Wherein Pd is the peak value detection threshold.

At total correlation power sequence Rx_power ^(sync)In search maximum power value (peak-peak) P_peak and corresponding peak value position Po_peak thereof.

Extremely

Be signal peak window (peakwindow);

Extremely

Be leading window (pre-window), corresponding average power is P_aver_befo, W ₁For window is long in advance;

Extremely

Be lag windwo (post-window) that corresponding average power is P_aver_afte, W ₂For lag window long.

The function of this testing conditions is to be used for difference between the average power in maximum power value and leading, the lag windwo in the detection peak window, if P_peak-P_aver_befo〉Pd and P_peak-P_aver_afte〉Pd, then peak value testing conditions establishment.

The value of T should be 3 integral multiple.

3. collision detection

As shown in Figure 4.

Collision detection condition: P_peak-Pside 〉=Pc (dB)

Wherein Pc is the collision detection thresholding.

When having only a user to insert, the total correlation power in the peak value window is very high, and the total correlation power outside the peak value window is very low.If when existing a plurality of users to insert, outside peak value window, also has higher total correlation power so.Therefore at first need the identification of signing to SYNC_UL, whether the detection peak window exists other higher total correlation power peak outward then, if its value is lower than given threshold value, then can thinks access interference (collision) does not take place, and SYNC_UL signs effective.The end position of collision detection window width from signal peak window starting position to the total correlation power sequence.

When considering up access, two user terminal UE have used identical SYNC_UL sign indicating number, access interference will occur like this.If detect access interference, then base station node B does not send response physical access channel (FPACH).If P_peak-Pside＜Pc (dB) then judges access interference to occur.

In the 4th step, physical access channel (FPACH) is arranged

In each subframe, may detect a plurality of SYNC_UL signatures, and the FPACH number that every subframe disposed in the sub-district may be less than detected number of signature, therefore need carry out processed according to the rank of signature.

All SYNC_UL signatures are kept in the formation in order, and each subframe all responds the signature of specific quantity, and Xiang Ying signature does not then continue to be kept in the formation, and its comparative lifetime adds 1.The initial value of each signature comparative lifetime is 0.The rule of response of signature is as follows:

1. at first select " comparative lifetime " maximum reliable signature;

2. if there is not reliable signature, then select prominent normal signature.

If exist a plurality of signatures to satisfy above-mentioned rule, then optional signature responds, and after the response, this signature is promptly deleted from formation.The comparative lifetime of each signature can not surpass a certain specified threshold in the formation, otherwise with deleted.

The device of raising synchronous detecting precision of the present invention consists of the following components, as shown in Figure 5:

A. signal receiving device (101)

Convert digital baseband signal to after the processing such as the amplification of the wireless signal process signal receiving device that antenna receives, filtering, down-conversion, analog to digital conversion, wherein sample rate is selected in analog to digital conversion.

B. matched filter (102)

The N that matched filter utilizes this sub-district to adopt _{SYNC_UL}Individual uplink synchronous

(SYNC_UL) sign indicating number respectively with protection at interval each antenna data on (GP) and uplink pilot time slot (UpPTS) the time slot interval be shifted relevantly, and obtain the related power sequence of each antenna.

C. local uplink synchronous (SYNC_UL) sign indicating number generating apparatus (103)

The function of local uplink synchronous (SYNC_UL) sign indicating number generating apparatus is to produce the N that adopt this sub-district _{SYNC_UL}Individual SYNC_UL sign indicating number.

D. the recognition device (104) of signing

The signature recognition device is at first with the related power sequence addition of each antenna, obtain the total correlation power sequence, then the total correlation power sequence is carried out peak value respectively and detect and collision detection, thereby determine whether to exist effective uplink synchronous (SYNC_UL) signature (user's access).

E. physical access channel (FPACH) arrangement (105)

Physical access channel (FPACH) arrangement responds uplink synchronous (SYNC_UL) signature in order successively according to the priority level of signature, promptly distributes corresponding FPACH.

Adopt the method for the invention and device, overcome the shortcoming of single-time sampling in the wireless communication system random access procedure, solve the synchronous detecting precision problem that exists in the prior art, provide a kind of method and apparatus of the raising synchronous detecting precision based on multiple sampling, thereby improved the performance of synchronous detecting.Choosing of sample rate be decided according to actual conditions, and it is all multifactor promptly to need to take all factors into consideration synchronous detecting precision, computation complexity and memory data output etc.

The present invention is applicable to synchronization CDMA (code division multiple access) communication system, be particularly useful for TD-SCDMA system (1.28Mcps TDD) and 3.84McpsTDD system in the 3-G (Generation Three mobile communication system), but be applicable to the frequency division multiple access of employing synchronization CDMA and the system of time division multiple access too, any engineer with knowledge background such as signal processing, communications, can design the method and apparatus that corresponding synchronous detects according to the present invention, it all should be included in thought of the present invention and the scope.

Claims (7)

1, a kind of method that improves synchronous detecting precision is used for the synchronous detecting of code division multiple address communication system based on uplink pilot time slot, and it may further comprise the steps:

A) antenna data segment is obtained, in order to determine the data segment at uplink synchronous code place;

B) matched filtering: with the N of current area _{SYNC_UL}Individual uplink synchronous code respectively with protection at interval and the reception of the antenna on uplink pilot time slot interval data be shifted relevantly, obtain the related power sequence;

C) signature identification, in order to the total correlation power sequence is detected judgement, under the situation that satisfies the predetermined detection condition, just judging has uplink synchronous to insert; Described detection comprises that peak value detects and collision detection, satisfies the predetermined detection condition and is meant: when peak value detects, the maximum power value in the peak value window of definition and definition in advance, the difference between the interior average power of lag windwo is greater than a certain threshold value; When collision detection, if there is the outer higher total correlation power peak of peak value window, its value is lower than given parameter;

D) physical access channel arrangement in every subframe, is carried out processed according to the rank of a plurality of uplink synchronous signatures.

2, method according to claim 1 is characterized in that, described step a) also comprises:

Detection window comprises protection interval and uplink pilot time slot, and described data segment comprises L _DataIndividual chip, comprising protecting at interval and the number of chips summation of uplink pilot time slot, length is L _DataAn x SR sampled point, SR are sample rate, i.e. the sampling number of a chip.

3, method according to claim 2 is characterized in that, described sample rate SR value is 2,4,8.

4, method according to claim 1 is characterized in that, described step b) also comprises the following steps:

B1) the real number uplink synchronous code is carried out the plural number processing, i.e. employed plural uplink synchronous code in the system, $\underset{\&OverBar;}{s}=({\underset{\&OverBar;}{s}}_1,{\underset{\&OverBar;}{s}}_2,\&CenterDot;\&CenterDot;\&CenterDot;,{\underset{\&OverBar;}{s}}_{L_{\mathrm{SYNC\; UL}}})$ Can be by the real number uplink synchronous code $s=(s_1,s_2,\&CenterDot;\&CenterDot;\&CenterDot;,{\underset{\&OverBar;}{s}}_{L_{\mathrm{SYNC\; UL}}})$ Obtain, promptly

${\underset{\&OverBar;}{s}}_i=j^i\&CenterDot;s_i$ S _i∈{1，-1}，i＝1，2，...，L _{SYNC_UL} (1)

L in the formula _{SYNC_UL}The length of expression uplink synchronous code;

B2) correlated series of calculating uplink synchronous code and antenna data, the correlated series of each antenna is expressed as

$R^{\left(\mathrm{ka}\right)}=\underset{k,n}{\mathrm{\&Sigma;}}{r}_n^{\left(\mathrm{ka}\right)}\&CenterDot;{\left({\underset{\&OverBar;}{s}}_{k+i}\right)}^{*}---\left(2\right)$

In the formula

The reception data of representing ka antenna, () ^*The expression conjugate operation, subscript ka represents the antenna sequence number, ka=0,1 ..., Ka-1, Ka are antenna number;

B3) calculate the related power sequence of each antenna correspondence, promptly

$R_P^{\left(\mathrm{ka}\right)}={\left(\mathrm{Re}\left[R^{\left(\mathrm{ka}\right)}\right]\right)}^2+{\left(\mathrm{Im}\left[R^{\left(\mathrm{ka}\right)}\right]\right)}^2---\left(3\right)$

Re[in the formula] expression gets real part computing, Im[] expression gets imaginary-part operation.

5, method according to claim 1 is characterized in that, described step c) comprises the following steps:

C1) the total correlation power sequence calculates, and the related power sequence addition of each antenna obtains the total correlation power sequence, promptly

$R_{\mathrm{Power}}=\underset{\mathrm{ka}=0}{\overset{\mathrm{Ka}-1}{\mathrm{\&Sigma;}}}{R}_P^{\left(\mathrm{ka}\right)}---\left(4\right)$

Ka is an antenna number in the formula, and subscript ka represents the antenna sequence number.

C2) peak value detects, at total correlation power sequence R _PowerIn search maximum power value P_peak and corresponding peak value position Po_peak thereof, define a signal peak window, this window is included peak, window is long to be a mouthful T;

Leading window of definition before peak value window, window is long to be W ₁

Lag windwo of definition after peak value window, window is long to be W ₂

The function that peak value detects is to be used for difference between maximum power value and leading, that lag windwo the is interior average power in the detection peak window, if the difference between the average power in maximum power value and leading, the lag windwo is greater than a certain threshold value, then the peak value testing conditions is set up;

C3) collision detection, at first to the uplink synchronous identification of signing, whether the detection peak window exists other higher total correlation power peak outward then, if its value is lower than given parameter, then can thinks access interference does not take place, and the uplink synchronous signature is effectively; The end position of collision detection window width from signal peak window starting position to the total correlation power sequence; If detect access interference, then the base station does not send the response physical access channel.

6, method according to claim 1, it is characterized in that described step d) comprises that also all uplink synchronous signatures are kept in the formation in order, each subframe all responds the signature of specific quantity, Xiang Ying signature does not then continue to be kept in the formation, and its comparative lifetime adds 1; The initial value of each signature comparative lifetime is 0, and the rule of response of signature is as follows:

D1) at first select the reliable signature of comparative lifetime maximum;

D2) if there is not reliable signature, then select prominent normal signature;

If exist a plurality of signatures to satisfy above-mentioned rule, then optional signature responds, and after the response, this signature is promptly deleted from formation, and the comparative lifetime of each signature can not surpass a certain specified threshold in the formation, otherwise with deleted.

7, a kind of device that improves synchronous detecting precision, it comprises following a few part:

One signal receiving device (101), be connected with antenna, convert digital baseband signal to after the processing such as the amplification of wireless signal this signal receiving device of process (101) that this antenna receives, filtering, down-conversion, analog to digital conversion, wherein sample rate is selected in analog to digital conversion;

One matched filter (102), and local uplink synchronous code generating apparatus (103), this this locality uplink synchronous code generating apparatus (103) produces the N that adopt this sub-district _{SYNC_UL}Individual uplink synchronous code; Described matched filter (102) is then used this N _{SYNC_UL}Individual uplink synchronous code respectively with protection at interval and each antenna data on the uplink pilot time slot interval be shifted relevantly, and obtain the related power sequence of each antenna;

One signature recognition device (104), this signature recognition device (104) is at first with the related power sequence addition of each antenna, obtain the total correlation power sequence, then the total correlation power sequence being carried out peak value respectively detects and collision detection, thereby determine whether to exist effective uplink synchronous signature, promptly the user inserts;

One physical access channel arrangement (105), this physical access channel arrangement (105) responds the uplink synchronous signature in order successively according to the priority level of signature, promptly distributes corresponding physical access channel.

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