CN104022862A - Fast timing synchronizing method of full-duplex communication system - Google Patents
Fast timing synchronizing method of full-duplex communication system Download PDFInfo
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- CN104022862A CN104022862A CN201410308546.3A CN201410308546A CN104022862A CN 104022862 A CN104022862 A CN 104022862A CN 201410308546 A CN201410308546 A CN 201410308546A CN 104022862 A CN104022862 A CN 104022862A
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Abstract
The invention relates to a fast timing synchronizing method of a full-duplex communication system, which belongs to the technical field of the timing synchronization of wireless communication. The method is characterized by comprising the steps: adopting two identical PN code sequences as pilot signals through a transmitting-terminal data frame, receiving the signal through a receiving terminal, delaying the signal for a PN code period, aligning a second PN code with a first PN code of the delayed received signal, multiplying the first PN code and the second PN code by taking the first PN code and the second PN code as corresponding sampling points, counting the quantity of the multiplied values which are greater than a set threshold value in the length of the PN code period, carrying out the multiplication operation of the corresponding sampling points on the delayed receiving signal and the local PN code sequence if the statistic quantity is greater than a critical value of the quantity, then counting the quantity of the multiplied values which are greater than the set threshold value in the length of one PN code period, and if the statistic quantity still exceeds the critical value of the set quantity, determining the head part of a delaying unit as a timing synchronizing point. By adopting the method, the timing synchronization is realized by ingeniously utilizing the self-correlation characteristic of the PN code and the random characteristic of the noise, the multiplication times can be reduced, the operand is reduced, the accumulation operation is not needed by adopting the threshold value comparison way, and the timing synchronizing point can be rapidly and accurately found.
Description
Technical field
The present invention relates to a kind of quick time synchronization method of full duplex communication system, specifically relate to a kind of PN code synchronization acquiring method of delay multiplication.
Background technology
Timing Synchronization is one of key technology of full duplex communication system, and the performance of Timing Synchronization directly affects communication quality.The Timing Synchronization algorithm of radio communication is mainly divided into 3 classes: based on training sequence synchronized algorithm, based on Cyclic Prefix synchronized algorithm and blind synchronized algorithm, at present the most frequently used is exactly the synchronized algorithm based on training sequence.In the classic algorithm of the synchronized algorithm based on training sequence, the PN code sequences that adopt, as training sequence, have determined the quality of Timing Synchronization more to the performance of PN code synchronization acquistion.A lot of scholars to PN code synchronization acquistion done a large amount of research, for example, the Li Caixia of University Of Hebei, " OFDM Timing Synchronization algorithm " (ISSN1000-1565 that the teacher such as Zheng Xiaokun and Han Xiaoxia delivers on University Of Hebei's journal (natural science edition), Vol.31, No.6, November2011, 31 (6)) in the synchronized algorithm proposing, adopted sliding correlation method to catch PN code, use sliding correlation method, when the phase difference of two PN codes or time difference are when very large, its relative sliding velocity is very slow, to such an extent as to the overlong time of search Timing Synchronization point, especially long to the capture time of long PN code, have to adopt some special shorter code sequences, in addition, adopt the relevant each sampled point that slides to need to carry out the multiply-add operation that length is a PN code, operand is larger.
Summary of the invention
The present invention is directed to above defect and deficiency, propose a kind of quick time synchronization method of full duplex communication system, the method is compared with conventional method under the prerequisite of accurately catching, and speed is faster, and operand is less, and hardware is realized simpler.
The inventive method realizes by following concrete technical scheme.
A quick time synchronization method for full duplex communication system, is realized by following system, and this system comprises delay unit, multiplying unit 1, threshold value comparing unit 1, multiplying unit 2, threshold value comparing unit 2 and local PN code generation unit, wherein:
Delay unit, completes time delay to received signal, and delay time is the cycle of a PN code;
Multiplying unit 1, completes the reception signal after former reception signal and time delay is carried out to pointwise phase multiplication;
Threshold value comparing unit 1, completes and receives signal and receive after the time delay multiplying (corresponding sampled point phase multiplication) of signal, adds up the quantity that is greater than setting threshold in this PN code Cycle Length multiplying value;
Local PN code generation unit, completes and produces and receive identical PN code in signal;
Multiplying unit 2, does multiplication (corresponding sampled point multiplies each other) computing to the reception signal of a PN code Cycle Length in delay unit and the local PN code producing;
Threshold value comparing unit 2, adds up the quantity that is greater than setting threshold in multiplying unit 2 multiplied value out;
The method step is as follows:
(1) transmitting terminal framing
Transmitting terminal adds two identical PN code sequences as pilot signal in the frame head part of frame data, and PN code Cycle Length is K;
(2) setting threshold and the critical value that is greater than number of thresholds
According to system emulation and actual test, the decision threshold arranging after multiplication (corresponding sampled point multiplies each other) computing is corr_threshold, and setting the critical value that is greater than the quantity of threshold value in K multiplied value of a PN code Cycle Length is N;
(3) receive signal lag multiplying
PN code cycle K of time delay to received signal, and receive signal and the former reception signal that signal does after time delay and do multiplication (corresponding sampled point multiplies each other) computing;
(4) threshold value comparative statistics
The relatively value after multiplication (corresponding sampled point multiplies each other) computing and the size of threshold value corr_threshold, the quantity that statistics is greater than threshold value corr_threshold in K multiplication value of a PN code length is M;
(5) time delayed signal and the multiplying of local PN code
If the quantity M of statistics exceedes the critical value N of setting, do multiplication (corresponding sampled point multiplies each other) computing with signal and the local PN code producing of time delay again, execution step (6), the quantity M of statistics is not more than the critical value N of setting else if, returns to (3) step;
(6) Timing Synchronization point judgement
Multiplication value after comparison step (5) multiplying and the size of threshold value corr_threshold, and to add up the quantity that is greater than threshold value corr_threshold in K multiplication value of a PN code length be L, if statistical magnitude L is still greater than critical value N, just find Timing Synchronization point, Timing Synchronization completes, otherwise returns to (3) step.
Described PN code be have with the similar automatic correlative property of white noise+1 and-1 bipolar coding sequence forming.
Time synchronization method provided by the present invention, the ingenious stochastic behaviour that has utilized PN code autocorrelation performance and noise has been realized Timing Synchronization, greatly reduce multiplication number of times, operand and complexity are reduced, adopt the mode of threshold value comparison, without carrying out accumulating operation, can quick and precisely find Timing Synchronization point.
Brief description of the drawings
The structure chart of one frame data when Fig. 1 is transmitting terminal framing of the present invention, frame header is divided and is comprised 2 identical PN code sequences, and wherein the length of each PN code sequence is K, after framing, launches.
Fig. 2 is the structured flowchart of receiving terminal PN code acquisition procedure in the inventive method.
Fig. 3 is the time delay graph of a relation that receives signal in the inventive method and receive signal, receives signal by a PN code cycle of delay unit time delay in figure, and second the PN code that receives signal alignd with first PN code that receives signal after time delay.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described, but be not limited to this.
Embodiment:
The embodiment of the present invention as shown in Figure 2, a kind of quick time synchronization method of full duplex communication system, realized by following system, this system comprises delay unit, multiplying unit 1, threshold value comparing unit 1, multiplying unit 2, threshold value comparing unit 2 and local PN code generation unit, wherein:
Delay unit, completes time delay to received signal, and delay time is the cycle of a PN code;
Multiplying unit 1, completes the reception signal after former reception signal and time delay is carried out to pointwise phase multiplication;
Threshold value comparing unit 1, completes and receives signal and receive after the time delay multiplying (corresponding sampled point phase multiplication) of signal, adds up the quantity that is greater than setting threshold in this PN code Cycle Length multiplying value;
Local PN code generation unit, completes and produces and receive identical PN code in signal;
Multiplying unit 2, does multiplication (corresponding sampled point multiplies each other) computing to the reception signal of a PN code Cycle Length in delay unit and the local PN code producing;
Threshold value comparing unit 2, adds up the quantity that is greater than setting threshold in multiplying unit 2 multiplied value out;
The method step is as follows:
(1) transmitting terminal framing
Transmitting terminal adds two identical PN code sequences as pilot signal in the frame head part of frame data, and PN code Cycle Length is K;
(2) setting threshold and the critical value that is greater than number of thresholds
According to system emulation and actual test, the decision threshold arranging after multiplication (corresponding sampled point multiplies each other) computing is corr_threshold, and setting the critical value that is greater than the quantity of threshold value in K multiplied value of a PN code Cycle Length is N;
(3) receive signal lag multiplying
PN code cycle K of time delay to received signal, and receive signal and the former reception signal that signal does after time delay and do multiplication (corresponding sampled point multiplies each other) computing;
(4) threshold value comparative statistics
The relatively value after multiplication (corresponding sampled point multiplies each other) computing and the size of threshold value corr_threshold, the quantity that statistics is greater than threshold value corr_threshold in K multiplication value of a PN code length is M;
(5) time delayed signal and the multiplying of local PN code
If the quantity M of statistics exceedes the critical value N of setting, do multiplication (corresponding sampled point multiplies each other) computing with signal and the local PN code producing of time delay again, execution step (6), the quantity M of statistics is not more than the critical value N of setting else if, returns to (3) step;
(6) Timing Synchronization point judgement
Multiplication value after comparison step (5) multiplying and the size of threshold value corr_threshold, and to add up the quantity that is greater than threshold value corr_threshold in K multiplication value of a PN code length be L, if statistical magnitude L is still greater than critical value N, just find Timing Synchronization point, Timing Synchronization completes, otherwise returns to (3) step.
Claims (1)
1. a quick time synchronization method for full duplex communication system, is realized by following system, and this system comprises delay unit, multiplying unit 1, threshold value comparing unit 1, multiplying unit 2, threshold value comparing unit 2 and local PN code generation unit, wherein:
Delay unit, completes time delay to received signal, and delay time is the cycle of a PN code;
Multiplying unit 1, completes the reception signal after former reception signal and time delay is carried out to pointwise phase multiplication;
Threshold value comparing unit 1, completes and receives signal and receive after the time delay multiplying of signal, adds up the quantity that is greater than setting threshold in this PN code Cycle Length multiplying value;
Local PN code generation unit, completes and produces and receive identical PN code in signal;
Multiplying unit 2, does multiplying to the reception signal of a PN code Cycle Length in delay unit and the local PN code producing;
Threshold value comparing unit 2, adds up the quantity that is greater than setting threshold in multiplying unit 2 multiplied value out;
The method step is as follows:
(1) transmitting terminal framing
Transmitting terminal adds two identical PN code sequences as pilot signal in the frame head part of frame data, and PN code Cycle Length is K;
(2) setting threshold and the critical value that is greater than number of thresholds
According to system emulation and actual test, the decision threshold arranging after multiplying is corr_threshold, and setting the critical value that is greater than the quantity of threshold value in K multiplied value of a PN code Cycle Length is N;
(3) receive signal lag multiplying
PN code cycle K of time delay to received signal, and receive signal and the former reception signal that signal does after time delay and do multiplying;
(4) threshold value comparative statistics
The relatively value after multiplying and the size of threshold value corr_threshold, the quantity that statistics is greater than threshold value corr_threshold in K multiplication value of a PN code length is M;
(5) time delayed signal and the multiplying of local PN code
If the quantity M of statistics exceedes the critical value N of setting, do multiplying with signal and the local PN code producing of time delay again, execution step (6), the quantity M of statistics is not more than the critical value N of setting else if, returns to (3) step;
(6) Timing Synchronization point judgement
Multiplication value after comparison step (5) multiplying and the size of threshold value corr_threshold, and to add up the quantity that is greater than threshold value corr_threshold in K multiplication value of a PN code length be L, if statistical magnitude L is still greater than critical value N, just find Timing Synchronization point, Timing Synchronization completes, otherwise returns to (3) step.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101534280A (en) * | 2009-04-15 | 2009-09-16 | 大唐微电子技术有限公司 | Timing synchronous receiving method and device thereof |
| CN101577604A (en) * | 2006-07-20 | 2009-11-11 | 上海高清数字科技产业有限公司 | PN carrier acquisition device and method |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101577604A (en) * | 2006-07-20 | 2009-11-11 | 上海高清数字科技产业有限公司 | PN carrier acquisition device and method |
| CN101534280A (en) * | 2009-04-15 | 2009-09-16 | 大唐微电子技术有限公司 | Timing synchronous receiving method and device thereof |
Non-Patent Citations (1)
| Title |
|---|
| 李加升: "基于IEEE802.11a的OFDM定时同步算法及FPGA实现", 《计算机工程与科学》 * |
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