CN100508428C - A method and device for improving synchronization detection accuracy - 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 method and device for improving synchronization detection accuracy

technical field

The present invention relates to a method and device for random access in a wireless communication system, in particular to a method and device for synchronous detection based on uplink pilot time slots in a code division multiple access communication system.

Background technique

In the uplink of a synchronous CDMA (Code Division Multiple Access, Code Division Multiple Access) communication system, multiple user terminals UE (User Equipment) send signals to the base station (Node B), in order to prevent mutual interference between different user signals , it is necessary to perform synchronous detection and control on each user to ensure that they arrive at the base station at the same time.

The wireless frame of the synchronous CDMA communication system includes several subframes, and in each subframe, in addition to multiple regular time slots, it also includes 3 special time slots, namely the downlink pilot time slot (DwPTS), the guard interval (GP) Slot and uplink pilot time slot (UpPTS), where UpPTS is designed for uplink pilot and synchronization, and consists of uplink synchronization (SYNC_UL) code and guard interval inside the time slot.

In a synchronous CDMA communication system, random access synchronization detection refers to the establishment process of uplink synchronization. After the user terminal UE is turned on, it must first establish downlink synchronization with the cell. Uplink synchronization can only be established under the condition of downlink synchronization.

The establishment of uplink synchronization is completed in the random access process, involving uplink pilot channel (UpPCH) and physical random access channel (PRACH). When the user terminal UE performs random access, it first sends an uplink synchronization (SYNC_UL) code in the uplink pilot time slot (UpPTS). Send a confirmation message to the user terminal UE on the incoming channel (FPACH), and then the user terminal UE can send access information to the base station NodeB on the allocated physical random access channel (PRACH), and finally the base station NodeB sends the necessary information To the user terminal UE, the call setup is completed.

After detecting the SYNC_UL sequence in the search window, the base station Node B estimates the corresponding delay, and then replies to the user terminal UE by sending adjustment information, so that the user terminal UE adjusts the transmission time when it transmits next time. This is done over the next few subframes via FPACH. After the PRACH is sent, uplink synchronization is established. The uplink synchronization process can also be used to re-establish uplink synchronization when uplink synchronization is lost.

Synchronous detection identifies the SYNC_UL code by analyzing the guard interval and the antenna data of the uplink pilot time slot. If a valid SYNC_UL code is detected, the corresponding parameter measurement task is completed.

The prior art on synchronization detection is described in the following documents:

[1] Patent "Synchronization detection circuit for radio communication, has matched filter to output correlation val UE between spreading code and data obtained by sampling spread signal using one-chip cycle sampling clock". U.S. patent, publication number: US 2003015:2208, publication date 3 August 14, 2003; Japanese patent, publication number: JP 2003234677, publication date: August 22, 2003; Chinese patent, publication number: CN 1437323, publication date: August 20, 2003

[2] Patent "Synchronization detecting apparatus has synchronization detector which detects synchronization using demodulated synchronization signal depending on channel estimation result using pilot signal". U.S. patent, publication number: US 20020093988, publication date: July 1, 2002; : JP 2002217775, publication date: August 2, 2002

[3] Patent "A method and device for capturing random access channel preamble in WCDMA system". Chinese patent, publication number: 1389995, publication date: January 8, 2003

[4] Zhou Haijun, Yan Xiaoli, Xiong Simin, Xie Xianzhong. "TD-SCDMA System Random Access Performance Analysis". Journal of Chongqing University of Posts and Telecommunications, Volume 14, Issue 4, December 2002, Pages 19-23

In the prior art, the synchronous detection process is based on single sampling, that is, one chip (chip) corresponds to only one sampling point. In this way, if the sampling point deviates from the output peak value of the root-raised cosine filter, it will greatly affect the signal-to-interference-noise ratio of the received data, thereby degrading the synchronous detection performance.

Contents of the invention

The purpose of the present invention is to provide a method and device for improving the accuracy of synchronous detection in order to overcome the shortcomings of single sampling in the random access process of a synchronous CDMA communication system in order to solve the problems in the prior art. Due to the existing problem of synchronization detection accuracy, using the uplink synchronization (SYNC_UL) code in the uplink pilot time slot (UpPTS), a method and device for improving synchronization detection accuracy based on multiple sampling are given, thereby improving the synchronization detection accuracy. performance.

Technical scheme of the present invention is as follows:

A method for improving the accuracy of synchronous detection, used for synchronous detection based on uplink pilot time slots in a code division multiple access communication system, comprising the following steps:

a) Antenna data segment acquisition to determine the data segment where the uplink synchronization code is located;

b) Matched filtering: use the N _{SYNC_UL} uplink synchronization codes of the current cell to shift and correlate with the data received by the antenna on the guard interval and the uplink pilot time slot interval respectively, and obtain the correlation power sequence;

c) signature identification, which is used to detect and judge the total correlation power sequence, and only judge that there is uplink synchronous access when the predetermined detection condition is met;

d) For fast physical access channel arrangement, in each subframe, priority processing is performed according to the levels of multiple uplink synchronization signatures.

The method, wherein, the step a) also includes: the detection window includes a guard interval and an uplink pilot time slot, and the data segment includes L _data chips, which include the guard interval and the uplink pilot time slot The sum of the number of chips has a length of L _data × SR sampling points, and SR is the sampling rate, that is, the number of sampling points of one chip.

The method, wherein the sampling rate SR is 2, 4, 8.

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

b1) Complexize the real uplink synchronization code, that is, the complex uplink synchronization code used in the system $\underset{\&OverBar;}{\mathrm{the\; s}}=({\underset{\&OverBar;}{\mathrm{the\; s}}}_1,{\underset{\&OverBar;}{\mathrm{the\; s}}}_2,...,{\underset{\&OverBar;}{\mathrm{the\; s}}}_{L_{\mathrm{sync}\_\mathrm{ul}}})$ Uplink Synchronization Code $\mathrm{the\; s}=({\mathrm{the\; <figure-callout\; id="1"\; label="s"\; filenames="C200410027884E00221.png"\; state="\{\{state\}\}">s</figure-callout>}}_1,{\mathrm{the\; s}}_2,...,{\mathrm{the\; s}}_{L_{\mathrm{sync}\_\mathrm{ul}}})$ get, ie

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

(1)

In the formula, L _{SYNC_UL} represents the length of the SYNC_UL code;

b2) Calculate the correlation sequence between the uplink synchronization code and the antenna data, and the correlation sequence of each antenna is expressed as

${\mathrm{<span\; class="notranslate">\; R</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{<span\; class="notranslate">\; (</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

表示第Ka个天线的接收数据，(·)^*表示共轭运算，上标Ka表示天线序号，Ka＝0，1，…，Ka-1，Ka为天线数；In the formula

Represents the received data of the Ka-th antenna, (·) ^* represents the conjugate operation, the superscript Ka represents the serial number of the antenna, Ka=0, 1,..., Ka-1, Ka is the number of antennas;

b3) Calculate the correlation power sequence corresponding to each antenna, namely

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Re</span>}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; R</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Im</span>}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; R</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, Re[·] represents the operation of taking the real part, and Im[·] represents the operation of taking the imaginary part.

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

c1) Calculation of the total correlation power sequence, adding the correlation power sequences of each antenna to obtain the total correlation power sequence, that is

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; power</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; Ka</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In the formula, Ka is the number of antennas, and the superscript ka represents the serial number of the antennas.

T；c2) Peak detection, search for the maximum power value P_peak and its corresponding peak position Po_peak in the total correlation power sequence R _Power , define a signal peak window, the window includes the peak position, and the window length is

T;

Define a leading window before the peak window, and the window length is W ₁ ;

Define a hysteresis window after the peak window, the window length is W ₂ ;

The function of peak detection is to detect the difference between the maximum power value in the peak window and the average power in the leading and lagging windows, if the difference between the maximum power value and the average power in the leading and lagging windows is greater than a certain gate limit, then the peak detection condition is established;

c3) Collision detection, firstly perform signature identification on the uplink synchronization, and then detect whether there are other higher total correlation power peaks outside the peak window, if the value is lower than the given parameter, it can be considered that no access conflict has occurred, and the uplink synchronization The signature is valid; the collision detection window width is from the start position of the signal peak window to the end position of the total correlation power sequence; if an access conflict is detected, the base station does not send a response Fast Physical Access Channel (FPACH).

The method, wherein, the step d) also includes storing all uplink synchronization signatures in the queue in order, each subframe responds to a specific number of signatures, and the unresponsive signatures continue to be stored in the queue, which is relatively The lifetime is increased by 1; the initial value of the relative lifetime of each signature is 0, and the signature response rules are as follows:

d1) First select the reliable signature with the largest relative lifetime;

d2) If there is no reliable signature, select the normal signature with the highest power;

If there are multiple signatures that meet the above rules, choose a signature to respond. After the response, the signature will be deleted from the queue. The relative lifetime of each signature in the queue cannot exceed a certain threshold, otherwise it will be deleted .

A device for improving the accuracy of synchronous detection, which includes the following parts:

A signal receiving device (101), connected with an antenna, the wireless signal received by the antenna is converted into a digital baseband signal after being amplified, filtered, down-converted, analog-to-digital converted, etc. by the signal receiving device (101), wherein the sampling rate is Select in the analog-to-digital conversion;

A matched filter (102), and a local uplink synchronization code generating device (103), the local uplink synchronization code generating device (103) generates N _{SYNC_UL} uplink synchronization codes adopted by the community; the matched filter (102) Then use the N _{SYNC_UL} uplink synchronization codes to perform shift correlation with the guard interval and the data of each antenna on the uplink pilot time slot interval, and obtain the correlation power sequence of each antenna;

A signature recognition device (104), the signature recognition device (104) first adds up the correlation power sequences of each antenna to obtain a total correlation power sequence, and then performs peak detection and collision detection on the total correlation power sequence to determine whether there is Valid uplink synchronization signature, that is, user access;

A fast physical access channel arrangement device (105), the fast physical access channel arrangement device (105) sequentially responds to the uplink synchronization signature according to the priority level of the signature, that is, allocates the corresponding fast physical access channel channel.

A method and device for improving synchronization detection accuracy provided by the present invention, due to the use of the uplink synchronization (SYNC_UL) code in the uplink pilot time slot (UpPTS), provides a method for improving synchronization detection accuracy based on multiple sampling The method and the device thereby improve the performance of synchronous detection and the precision of synchronous detection.

Description of drawings

Specific embodiments of the present invention will be described in detail by referring to and in conjunction with the accompanying drawings of the present invention below, so that the purpose, technical solutions and advantages of the present invention are clearer and easier to understand. In the accompanying drawings:

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

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

Fig. 3 is the schematic diagram of the peak detection condition in the synchronous detection signature identification of the inventive method;

Fig. 4 is the schematic diagram of the conflict detection condition in the synchronous detection signature identification of the method of the present invention;

Fig. 5 is a structural block diagram of the synchronous detection device of the device of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the implementation of technical scheme is described in further detail:

The device for improving synchronous detection accuracy described in the present invention is made up of the following several parts:

A. Signal receiving device (101)

B. Matched filter (102)

C. Local uplink synchronization (SYNC_UL) code generating device (103)

D. Signature recognition device (104)

E. Fast Physical Access Channel (FPACH) Scheduling Device (105)

The wireless signal received by the antenna is converted into a digital baseband signal after being amplified, filtered, down-converted, and analog-to-digital converted by the signal receiving device (101), wherein the sampling rate is selected in the analog-to-digital conversion; the local uplink synchronization (SYNC_UL) code The function of generating device (103) is to produce the _{N SYNC_UL} codes that this community adopts; Carry out shift correlation and obtain the correlation power sequence of each antenna; the signature recognition device (104) first adds the correlation power sequences of each antenna to obtain the total correlation power sequence, and then performs peak detection and collision detection on the total correlation power sequence respectively , thereby determining whether there is an effective SYNC_UL signature (user access); Fast Physical Access Channel (FPACH) arrangement device (105) responds to the SYNC_UL signature in sequence according to the priority level of the signature, that is, allocates the corresponding FPACH channel.

The method for improving synchronous detection accuracy described in the present invention is as follows:

The first step is to obtain the antenna data segment

This step is used to determine the data segment where the uplink synchronization (SYNC_UL) is located. The detection window includes the guard interval (GP) and the uplink pilot time slot (UpPTS). The data segment includes L _data chips, that is, includes the guard interval and the uplink pilot The total number of chips in a time slot has a length of L _data × SR sampling points, and SR is a sampling rate, that is, the number of sampling points in one chip. Considering that the synchronization accuracy of a synchronous CDMA communication system is usually 1/8 chip, then SR can be 1, 2, 4, 8, and the case of SR=1 is the existing synchronization detection technology based on single sampling, SR=2 , 4, and 8 are the synchronous detection technology based on multiple sampling proposed by the present invention. The larger the SR value, the higher the synchronization detection accuracy, but the greater the computational complexity and data storage capacity, so the selection of the SR value should be determined according to the actual situation.

The second step, matched filtering

In order to detect whether there is SYNC_UL access in the interval between the guard interval and the uplink pilot time slot, it is first necessary to use the N _{SYNC_UL} SYNC_UL codes of the current cell to shift and correlate with the data received by the antenna on the guard interval and the uplink pilot time slot interval respectively , to get the correlation power sequence.

Matched filtering can include the following steps:

1. Complexize the real SYNC_UL code, that is, the complex SYNC_UL code used in the system $\underset{\&OverBar;}{\mathrm{the\; s}}=({\underset{\&OverBar;}{\mathrm{the\; s}}}_1,{\underset{\&OverBar;}{\mathrm{the\; s}}}_2,...,{\underset{\&OverBar;}{\mathrm{the\; s}}}_{L_{\mathrm{sync}\_\mathrm{ul}}})$ Can be coded by real SYNC_UL

$\mathrm{the\; s}=({\mathrm{the\; <figure-callout\; id="1"\; label="s"\; filenames="C200410027884E00221.png"\; state="\{\{state\}\}">s</figure-callout>}}_1,{\mathrm{the\; s}}_2,...,{\mathrm{the\; s}}_{L_{\mathrm{sync}\_\mathrm{ul}}})$ get, ie

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

In the formula, L _{SYNC_UL} represents the length of the SYNC_UL code.

2. Calculate the correlation sequence between the SYNC_UL code and the antenna data. The correlation sequence of each antenna is expressed as

${\mathrm{<span\; class="notranslate">\; R</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}{\mathrm{<span\; class="notranslate">\; r</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>{<span\; class="notranslate">\; (</span>{\underset{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; *</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

表示第ka个天线的接收数据，(·)^*表示共轭运算，上标ka表示天线序号，ka＝0，1，…，KA-1，Ka为天线数。In the formula

Indicates the received data of the kath antenna, (·) ^* indicates the conjugate operation, the superscript ka indicates the serial number of the antenna, ka=0, 1, ..., KA-1, and Ka is the number of antennas.

3. Calculate the correlation power sequence corresponding to each antenna, namely

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Re</span>}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; R</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Im</span>}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; R</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, Re[·] represents the operation of taking the real part, and Im[·] represents the operation of taking the imaginary part.

The third step, signature identification (Signature Identification)

This step may further include the following steps:

1. Total correlation power sequence calculation

The correlation power sequence of each antenna is added to obtain the total correlation power sequence, that is,

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; power</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; Ka</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In the formula, Ka is the number of antennas, and the superscript ka represents the serial number of the antennas.

Signature recognition is to detect and judge the total correlation power sequence. Only when the detection conditions described below are met, it is judged that there is SYNC_UL access.

2. Peak detection

The maximum power value (maximum peak value) P_peak and its corresponding peak position Po_peak are searched in the total correlation power sequence R _Power .

Define a signal peak window (peak window), which includes the peak position, and the window length is

A pre-window (pre-window) is defined before the peak window, and the window length is W ₁ .

A lag window (post-window) is defined after the peak window, and the window length is W ₂ .

The function of peak detection is to detect the difference between the maximum power value in the peak window and the average power in the leading and lagging windows, if the difference between the maximum power value and the average power in the leading and lagging windows is greater than a certain gate limit, the peak detection condition is established.

3. Conflict detection

When only one user is connected, the total correlation power inside the peak window is high, while the total correlation power outside the peak window is very low. There may also be a higher total correlation power outside the peak window if there are multiple user accesses. Therefore, it is first necessary to identify the signature of SYNC_UL, and then detect whether there are other higher total correlation power peaks outside the peak window. If the value is lower than the given parameter, it can be considered that no access conflict (collision) has occurred, and the SYNC_UL signature is valid . The collision detection window width is from the beginning position of the signal peak window to the end position of the total correlation power sequence.

Considering uplink access, two user terminals UE use the same SYNC_UL code, so access conflict will occur. If an access collision is detected, the base station Node B does not send a response Fast Physical Access Channel (FPACH).

The fourth step, fast physical access channel (FPACH) arrangement

In each subframe, multiple SYNC_UL signatures may be detected, and the number of FPACHs configured in each subframe in the cell may be less than the number of detected signatures, so it needs to be prioritized according to the signature level.

All SYNC_UL signatures are stored in the queue in order, and each subframe responds to a specific number of signatures, and the unresponsive signatures continue to be stored in the queue, and their "relative lifetime" is increased by 1. The initial value of each signature's "relative lifetime" is 0. The signature response rules are as follows:

① First select the reliable signature with the largest "relative lifetime";

② If there is no reliable signature, select the normal signature with the highest power.

If there are multiple signatures that meet the above rules, choose one signature to respond. Upon response, the signature is removed from the queue. The "relative lifetime" of each signature in the queue cannot exceed a certain threshold, otherwise it will be deleted.

The wireless frame of the synchronous CDMA communication system includes several subframes, and in each subframe, in addition to multiple regular time slots, it also includes 3 special time slots, namely the downlink pilot time slot (DwPTS), the guard interval (GP) Slot and uplink pilot time slot (UpPTS), where the uplink pilot time slot is designed for uplink pilot and synchronization, and consists of uplink synchronization (SYNC_UL) code and guard interval inside the time slot. As shown in Figure 1 and Figure 2.

Specifically, the steps of the method for improving the accuracy of synchronous detection described in the present invention are as follows:

The first step is to obtain the antenna data segment

This step is used to determine the data segment where the uplink synchronization (SYNC_UL) is located, the detection window includes the guard interval (GP) and the uplink pilot time slot (UpPTS), and the data segment includes L _data chips (that is, includes the guard interval and the uplink pilot The total number of chips in the time slot), the length is L _data × SR sampling points, and SR is the sampling rate, that is, the number of sampling points in one chip. Considering that the synchronization accuracy of a synchronous CDMA communication system is usually 1/8 chip, SR can be 1, 2, 4, 8. The case of SR=1 is the existing synchronous detection technology based on single sampling. The case of SR=2, 4, 8 is the synchronous detection technology based on multiple sampling proposed by the present invention. The larger the SR value, the higher the synchronization detection accuracy, but the greater the computational complexity and data storage capacity, so the selection of the SR value should be determined according to the actual situation.

n＝0，1，…，L_data×SR-1。

的每一元素均为复数，上标ka表示天线序号，ka＝0，1，…，Ka-1，Ka为天线数。The obtained data segment is expressed as

n=0, 1, . . . , L _data × SR-1.

Each element of is a complex number, the superscript ka indicates the serial number of the antenna, ka=0, 1, ..., Ka-1, and Ka is the number of the antenna.

The second step, matched filtering

In order to detect whether there is SYNC_UL access in the interval between the guard interval and the uplink pilot time slot, it is first necessary to use the N _{SYNC_UL} SYNC_UL codes of the current cell to shift and correlate with the data received by the antenna on the guard interval and the uplink pilot time slot interval respectively , to get the correlation power sequence.

i＝0，1，…，L_data×SR-1的相关性。The function of matched filtering is to calculate the SYNC_UL code and antenna data of the base station (Node B)

Correlation of i=0, 1, . . . , L _data × SR-1.

The length of the SYNC_UL code is L _{SYNC_UL} chips. For the case of SR double sampling, the real number SYNC_UL code of L _{SYNC_UL} chips must be

i＝0，1，…，L_{sync_ul}-1转换成SR倍采样对应的L_{SYNC_UL}×SR点的实数SYNC_UL码

k＝0，1，…，L_{sync_ul}×SR-1，即

i=0, 1,..., L _{sync_ul} -1 is converted into the real number SYNC_UL code of L _{SYNC_UL} × SR points corresponding to SR times sampling

k=0, 1, ..., L _{sync_ul} × SR-1, namely

(5)

The superscript sync indicates the sequence number of the SYNC_UL code, and sync=0, 1, ..., N _{sync_ul} -1 (each cell includes N _{SYNC_UL} SYNC_UL codes).

i＝0，1，…，(L_{sync_ul}+L_data)×SR-1，其中SR倍采样情况的相关运算长度为(L_{SYNC_UL}+L_data)×SR。通常取L_{sync_ul}≤L_data≤2·L_{sync_ul}。The correlation operation result of the sync-th SYNC_UL code and the data of the ka-th antenna is expressed as i=0, 1,..., (L _{sync_ul} +L _data )×SR-1, the corresponding correlation power sequence is expressed as

i=0, 1, . . . , (L _{sync_ul} +L _data )×SR−1, where the correlation operation length in the case of SR multiple sampling is (L _{SYNC_UL} +L _data )×SR. Usually L _{sync_ul} ≤ L _data ≤ 2·L _{sync_ul} .

Matched filtering can include the following specific steps:

1. Complexize the real SYNC_UL code, namely

$\mathrm{<span\; class="notranslate">\; Sync</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; code</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; R</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; code</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&times;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

In the formula

表示下取整运算，(j)^m+1相当于上行同步码的复数化处理。

Indicates the bottom rounding operation, (j) ^m+1 is equivalent to the pluralization processing of the uplink synchronization code.

2. Calculate the correlation sequence between the SYNC_UL code and the antenna data, namely

$\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; cor</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; sync</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&CenterDot;</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Sync</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; code</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; )</span>}^{<span\; class="notranslate">\; *</span>}$

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 correlation power sequence corresponding to each antenna, namely

$\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; pow</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Re</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; cor</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; Im</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; cor</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In the formula, Re[·] represents the operation of taking the real part, and Im[·] represents the operation of taking the imaginary part.

In engineering applications, in order to reduce the computational complexity, correlation operations can be implemented using fast Fourier transform/inverse transform (FFT/IFFT) methods, where FFT/IFFT are complex FFT/IFFT. As mentioned above, the antenna data length is L _data × SR, so the number of bits of the FFT/IFFT is L _data × SR.

后面添加(L_data-L_{sync_ul})×SR位“0”，补齐至L_data×SR位。通常取L_{sync_ul}≤L_data≤2·L_{sync_ul}。For the convenience of calculating L _data × SR bit FFT/IFFT, the complex SYNC_UL code corresponding to L _{SYNC_UL} × SR point can be sampled at SR times

Add (L _data -L _{sync_ul} )×SR bit “0” to the end, and fill up to L _data ×SR bit. Usually L _{sync_ul} ≤ L _data ≤ 2·L _{sync_ul} .

Specifically, taking L _data = 2·L _{syc_ul} as an example, the steps to realize the correlation operation by using the FFT/IFFT method are as follows:

①

②

③

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

In the formula, FFT[·] represents fast Fourier transform, and IFFT[·] represents inverse fast Fourier transform.

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

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

⑥ $\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{bef}}_{\mathrm{no}}^{(\mathrm{ka},\mathrm{sync})}---\left(15\right)$

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

⑦ $\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{bef}}_{\mathrm{no}}^{(\mathrm{ka},\mathrm{sync})}+\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{aft}}_{\mathrm{no}}^{(\mathrm{ka},\mathrm{sync})}---\left(16\right)$

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

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

⑧ $\mathrm{Rx}\_{\mathrm{cor}}_i^{(\mathrm{ka},\mathrm{sync})}=\mathrm{Rx}\_\mathrm{cor}\_{\mathrm{aft}}_{\mathrm{no}}^{(\mathrm{ka},\mathrm{sync})}---\left(17\right)$

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

n=0, 1, ..., L _{sync_ul} × SR-1

Preferably, the N _{SYNC_UL} codes used by a subdistrict are definite, so when using the FFT/IFFT method to perform correlation operations, the FFT results of the SYNC_UL codes can be calculated in advance, that is, the FFT [Inv_sync_code ^{(sync )} ], and stored on the storage device, in case of direct call for related operations, thereby further reducing the computational complexity.

The third step, signature identification (Signature Identification)

This step may further include the following steps:

1. Total correlation power sequence calculation

The correlation power sequence of each antenna is added to obtain the total correlation power sequence, that is,

$\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; power</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}}{\overset{\mathrm{<span\; class="notranslate">\; Ka</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}\mathrm{<span\; class="notranslate">\; Rx</span>}<span\; class="notranslate">\; \_</span>{\mathrm{<span\; class="notranslate">\; pow</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; ka</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0,1</span>}<span\; class="notranslate">\; ,</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; ,</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; sync</span>}<span\; class="notranslate">\; \_</span>\mathrm{<span\; class="notranslate">\; ul</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; data</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; SR</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 18</span>}<span\; class="notranslate">\; )</span>$

In the formula, Ka is the number of antennas, the superscript ka represents the serial number of the antenna, and the superscript sync represents the serial number of the SYNC_UL code.

Signature recognition is to detect and judge the total correlation power sequence. Only when the detection conditions described below are met, it is judged that there is SYNC_UL access.

2. Peak detection

As shown in Figure 3.

Peak detection condition: P_peak-max[P_aver_befo, P_aver_afte]>Pd(dB)

Where Pd is the peak detection threshold.

The maximum power value (maximum peak value) P_peak and its corresponding peak position Po_peak are searched in the total correlation power sequence Rx_power ^(sync) .

至

为信号峰值窗口(peakwindow)；

to

is the signal peak window (peakwindow);

至

为超前窗口(pre-window)，对应的平均功率为P_aver_befo，W₁为超前窗长；

to

is the advance window (pre-window), the corresponding average power is P_aver_befo, and W ₁ is the length of the advance window;

至

为滞后窗口(post-window)，对应的平均功率为P_aver_afte，W₂为滞后窗长。

to

is the post-window, the corresponding average power is P_aver_afte, and W ₂ is the length of the post-window.

The function of this detection condition is to detect the difference between the maximum power value in the peak window and the average power in the leading and lagging windows. If P_peak-P_aver_befo>Pd and P_peak-P_aver_afte>Pd, the peak detection condition is established.

T的取值应为3的整数倍。

The value of T should be an integer multiple of 3.

3. Conflict detection

As shown in Figure 4.

Conflict detection condition: P_peak-Pside≥Pc(dB)

Wherein Pc is the collision detection threshold.

When only one user is connected, the total correlation power inside the peak window is high, while the total correlation power outside the peak window is very low. There may also be a higher total correlation power outside the peak window if there are multiple user accesses. Therefore, it is first necessary to perform signature identification on SYNC_UL, and then detect whether there are other higher total correlation power peaks outside the peak window. If its value is lower than a given threshold, it can be considered that no access conflict (collision) has occurred. The signature is valid. The collision detection window width is from the beginning position of the signal peak window to the end position of the total correlation power sequence.

Considering uplink access, two user terminals UE use the same SYNC_UL code, so access conflict will occur. If an access collision is detected, the base station Node B does not send a response Fast Physical Access Channel (FPACH). If P_peak-Pside<Pc(dB), it is determined that an access conflict occurs.

The fourth step, fast physical access channel (FPACH) arrangement

In each subframe, multiple SYNC_UL signatures may be detected, and the number of FPACHs configured in each subframe in the cell may be less than the number of detected signatures, so priority processing needs to be performed according to the level of the signatures.

All SYNC_UL signatures are stored in the queue in order, and each subframe responds to a specific number of signatures, and the unresponsive signatures continue to be stored in the queue, and their relative lifetimes are increased by 1. The initial value of the relative lifetime of each signature is 0. The signature response rules are as follows:

① First select the reliable signature with the largest "relative lifetime";

② If there is no reliable signature, select the normal signature with the highest power.

If there are multiple signatures that meet the above rules, choose one signature to respond, and after the response, the signature will be deleted from the queue. The relative lifetime of each signature in the queue cannot exceed a certain threshold, otherwise it will be deleted.

The device for improving synchronous detection accuracy described in the present invention is made up of the following several parts, as shown in Figure 5:

A. Signal receiving device (101)

The wireless signal received by the antenna is converted into a digital baseband signal after being amplified, filtered, down-converted, and analog-to-digital converted by the signal receiving device, and the sampling rate is selected in the analog-to-digital conversion.

B. Matched filter (102)

The matched filter uses the N _{SYNC_UL} uplink synchronization adopted by this cell

The (SYNC_UL) code is shifted and correlated with the data of each antenna on the guard interval (GP) and the uplink pilot time slot (UpPTS) time slot interval, and the correlation power sequence of each antenna is obtained.

C. Local uplink synchronization (SYNC_UL) code generating device (103)

The function of the local uplink synchronization (SYNC_UL) code generator is to generate N _{SYNC_UL} SYNC_UL codes used by the cell.

D. Signature recognition device (104)

The signature identification device first adds the correlation power sequences of each antenna to obtain the total correlation power sequence, and then performs peak detection and collision detection on the total correlation power sequence respectively, so as to determine whether there is a valid uplink synchronization (SYNC_UL) signature (user access ).

E. Fast Physical Access Channel (FPACH) Scheduling Device (105)

The fast physical access channel (FPACH) arrangement device responds to the uplink synchronization (SYNC_UL) signature in sequence according to the priority level of the signature, that is, allocates the corresponding FPACH.

By adopting the method and device of the present invention, the shortcoming of single sampling in the random access process of the wireless communication system is overcome, the problem of synchronous detection accuracy in the prior art is solved, and an improved synchronous detection based on multiple sampling is provided The method and device of precision, thereby improving the performance of synchronous detection. The selection of the sampling rate should be determined according to the actual situation, that is, it is necessary to comprehensively consider many factors such as synchronization detection accuracy, computational complexity, and data storage capacity.

The present invention is applicable to synchronous CDMA (Code Division Multiple Access) communication system, is particularly applicable to the TD-SCDMA system (1.28Mcps TDD) and the 3.84McpsTDD system in the third generation mobile communication system, but is also applicable to the frequency that adopts synchronous CDMA For the systems of division multiple access and time division multiple access, any engineer with knowledge backgrounds such as signal processing and communication can design corresponding synchronous detection methods and devices according to the present invention, which should be included in the idea and scope of the present invention.

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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