CN106953823B - A kind of wireless communication high-precision frame synchornization method based on synchronizing sequence - Google Patents
A kind of wireless communication high-precision frame synchornization method based on synchronizing sequence Download PDFInfo
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- CN106953823B CN106953823B CN201710137590.6A CN201710137590A CN106953823B CN 106953823 B CN106953823 B CN 106953823B CN 201710137590 A CN201710137590 A CN 201710137590A CN 106953823 B CN106953823 B CN 106953823B
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- synchronizing sequence
- base band
- wireless communication
- sync bit
- band data
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2656—Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
Abstract
The invention discloses a kind of wireless communication high-precision frame synchornization method based on synchronizing sequence, low-pass filtering is carried out to baseband signal first, carry out thick synchronization and data storage respectively later, thick synchronism output has the sync bit of certain error, data storage is to do data preparation in order to which subsequent progress essence synchronizes, the synchronous main points of essence be carried out it is non-it is down-sampled under cross-correlation, all information of synchronizing sequence are utilized, it is thus possible to obtain most accurate sync bit.Frame synchronization precision of the present invention is high, suitable for having the wireless communication system of fixed frame format.
Description
Technical field
The present invention relates to a kind of wireless communication high-precision frame synchornization method based on synchronizing sequence, belongs to wireless communication skill
Art.
Background technique
In wireless communication technique, especially with orthogonal frequency division multiplexing (Orthogonal Frequency Division
Multiplexing, OFDM) technology be representative the modulation scheme with fixed frame structure, transmitting terminal and receiving end must be in skies
The start position that the synchronization of progress radio frames in time on mouth, i.e. receiving end determine radio frames transmitted by transmitting terminal, thus
Receiving end can distinguish the position of each different transmission symbols of entire radio frames, prepare for subsequent demodulation.Frame synchronization is main
Have based on cyclic prefix and based on the two methods of synchronizing sequence, in the frame synchornization method based on synchronizing sequence: receiving
Base band data carry out cross-correlation with the synchronizing sequence that is locally stored, the peak value for finding cross-correlation output valve corresponds to synchronous sequence
The corresponding position of column, according to position of the synchronizing sequence in entire radio frames, to release the starting point of radio frames.
In order to match with the structure of radio frames, the length of synchronizing sequence is generally large；Simultaneously for transmission rate request
High system, sample rate is higher, then the base band data rate of system is big.In order to reduce the calculation times of cross correlation algorithm, drop
Low complex degree, current frame synchronization algorithm mostly can be down-sampled to base band data progress, then carry out cross-correlation.Although reducing in this way
Complexity, but has lost the precision of frame synchronization, certain error is caused to system.
Summary of the invention
Goal of the invention: synchronous in order to solve frame synchronization (the being classified as thick synchronization below) bring done after above-mentioned reduction sample rate
The inaccurate problem in position, while synchronous complexity is reduced as far as possible, the invention proposes a kind of based on the wireless of synchronizing sequence
Communicate high-precision frame synchornization method, compared to slightly synchronize be simply added into the very low module of complexity can on thick synchronous foundation,
Obtain accurate frame synchronization position.
In order to overcome the deficiencies in the prior art, the present invention provides one kind
Technical solution: to achieve the above object, the technical solution adopted by the present invention are as follows:
A kind of wireless communication high-precision frame synchornization method based on synchronizing sequence is used in a wireless communication system, to nothing
Synchronizing sequence in line frame is detected, and accurately determines wireless frame start position, solves radio frames time domain in wireless communication
On precise timing synchronization problem, while overcome the problems, such as general essence synchronous institute with resource consumption it is big；It specifically includes as follows
Step:
(1) low-pass filtering is carried out to the base band data received, eliminates the interference of asynchronous sequence signal；Using based on following
Ring prefix or frame synchornization method based on synchronizing sequence are slightly synchronized, and it is (i.e. thick synchronous to be navigated to obtain thick sync bit
Synchronizing sequence is receiving the start position in data frame), the original synchronizing sequence obtained according to thick sync bit is stored, this is original
The length of synchronizing sequence is L point；
(2) start the n-th point of original synchronizing sequence starting point forward, length is the data of L+2N+1 as base band number
According to storing the base band data；
(3) base band data of the original synchronizing sequence to L point and L+2N+1 point carries out cross-correlation calculation and (it is mutual to carry out 2N+1
Close), the cross-correlation calculation is down-sampled to the progress of original synchronizing sequence, therefore contains all information of original synchronizing sequence,
Improve the precision of precise synchronization position；
(4) peak value of cross correlation results is searched for, and finds the corresponding position of the peak value to get corresponding serial number is arrived；Mutually
The serial number for closing result is counted from the starting point of base band data, corresponding 1~2N+1 of serial number；The corresponding position of the peak value found is turned
It changes biasing into, i.e., subtracts N in serial number, so the range of biasing is (- N, N)；
(5) thick sync bit is added with biasing, as a result as final smart sync bit.
Preferably, in the step (2), N is the absolute value of thick synchronous worst error, i.e., slightly synchronous worst error is ± N；
Therefore, we are when positioning base band data, as long as expanding N number of point respectively before and after original synchronizing sequence may include all possibility
Synchronizing sequence, so peak value must can be found when doing L point cross-correlation calculation.
In the present invention, firstly, certain requirement has been done in the initial position and length to base band data, so that the base band number taken out
According to the range that can cover original synchronizing sequence completely；Secondly, using complete original synchronous sequence when carrying out cross-correlation calculation
Column, so that whole sampling point informations of original synchronizing sequence are utilized in cross-correlation calculation, it is ensured that the synchronous accuracy of essence；Separately
Outside, biasing is interpreted as the gap of smart sync bit Yu thick sync bit by we, and thick sync bit is added with biasing, can be obtained
To smart sync bit.
It should be noted that transmitting terminal of the present invention in system, it is necessary to stringent to send the wireless communication with fixed frame format
Number, and position of the synchronizing sequence in frame format cannot change
The utility model has the advantages that the wireless communication high-precision frame synchornization method provided by the invention based on synchronizing sequence, has as follows
A little, this essence synchronized algorithm is accurately found out between thick sync bit and actual synchronization position on the basis of traditional thick synchronization
Deviation, to calculate smart synchronous point, with it is thick it is synchronous compared be only added to 2N+1 L point cross-correlation, resource consumption is extremely low, together
It is high to walk precision；The present invention has rational design, and synchronous effect is obvious, and algorithm complexity is low.
Detailed description of the invention
Fig. 1 is implementation flow chart of the invention；
Fig. 2 is the range schematic diagram for the base band data that the present invention stores.
Specific embodiment
Below with reference to LTE SISO system, the present invention will be further explained.
LTE SISO system is divided into 10ms using strictly frame format, one radio frames of system, and each radio frames are divided into 10
A subframe, each subframe are divided into 2 time slots, include 7 OFDM symbols in each time slot, each symbol uses 2048 point IFFT tune
System, in addition cyclic prefix, a radio frames share 307200 points, and systematic sampling rate is 30.72MSamples/s, synchronizing sequence
It is added in first OFDM symbol of radio frames, length L is 2048, and synchronizing sequence here selects PSS sequence, and bandwidth is
0.465MHz, transmitter in strict accordance with frame format and must continue to send the radio frames for having PSS sequence, and receiver just can be carried out
Subsequent essence is synchronous.
In receiving end, by down coversion, base band data is obtained by ADC, filters out synchronizing sequence using low-pass filter first
Out-of-band interference signal eliminates the influence to subsequent synchronisation algorithm, gives two moulds simultaneously by the signal of low-pass filter
Block: thick synchronization module and base band data memory module, the selection of thick synchronization module is more, be based primarily upon at present it is down-sampled (can be with
Selecting down-sampled 16 times) progress cross-correlation obtains thick sync bit to base band data later, and the length of cross-correlator at this time is removed for L
It is here 128, which can generate certain error with down-sampled multiple；Base band data memory module is according to thick sync bit
It sets, stores the base band data in synchronizing sequence location, but do not know that the starting point of synchronizing sequence is located at stored base band data
Which point.
After storing data, the auto-correlation of L point is carried out, 2N+1 cross-correlation is carried out here, down-sampled 16 times the case where
Under, worst error 8, so N=8, carries out 17 L point cross-correlation altogether.
The search that peak value is carried out after cross-correlation, finds the corresponding coordinate of peak value, and 0~2N+1 is converted into biasing ,-N~N,
Thick sync bit is added with biasing again, the synchronous position of final essence can be obtained.
The above is only a preferred embodiment of the present invention, it should be pointed out that: for the ordinary skill people of the art
For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also answered
It is considered as protection scope of the present invention.
Claims (1)
1. a kind of wireless communication high-precision frame synchornization method based on synchronizing sequence, it is characterised in that: for being in wireless communication
In system, the synchronizing sequence in radio frames is detected, wireless frame start position is determined, specifically comprises the following steps:
(1) low-pass filtering is carried out to the base band data received, using based on cyclic prefix or based on the frame synchronization of synchronizing sequence
Method is slightly synchronized, and thick sync bit is obtained, and stores the original synchronizing sequence obtained according to thick sync bit, the original synchronization
The length of sequence is L point；
(2) start the n-th point of original synchronizing sequence starting point forward, length is the data of L+2N+1 as base band data,
Store the base band data；
(3) cross-correlation calculation is carried out to original synchronizing sequence and base band data；
(4) peak value of cross correlation results is searched for, and finds the corresponding position of the peak value to get corresponding serial number is arrived；Cross-correlation knot
The serial number of fruit is counted from the starting point of base band data, corresponding 1~2N+1 of serial number；The corresponding position of the peak value found is converted into
Biasing, i.e., subtract N in serial number, so the range of biasing is (- N, N)；
(5) thick sync bit is added with biasing, as a result as final smart sync bit；
In the step (2), N is the absolute value of thick synchronous worst error, i.e., slightly synchronous worst error is ± N.
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| CN109218247B (en) * | 2018-11-27 | 2020-11-24 | 威胜信息技术股份有限公司 | Timing synchronization method based on novel synchronization sequence |
| CN112398566B (en) * | 2020-11-16 | 2022-05-24 | 中国电子科技集团公司第二十九研究所 | High-precision arrival time calculation method and device for burst communication system |
| CN112702296B (en) * | 2020-12-18 | 2022-11-11 | 上海微波技术研究所（中国电子科技集团公司第五十研究所） | FPGA (field programmable Gate array) realization method and system for data synchronization parallelization in millimeter wave communication |
| CN114765528B (en) * | 2021-01-15 | 2023-09-26 | 烽火通信科技股份有限公司 | Frame synchronization method, device, equipment and readable storage medium |
| CN115333571B (en) * | 2022-06-22 | 2023-12-19 | 飞芯智控(成都)科技有限公司 | Synchronous processing method and device for frequency hopping communication system |
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| WO2006137023A3 (en) * | 2005-06-24 | 2007-03-08 | Koninkl Philips Electronics Nv | Method and apparatus for synchronization in wireless communication system |
| CN101778088A (en) * | 2010-03-12 | 2010-07-14 | 中国科学院声学研究所 | Training sequence frame timing synchronized method based on pseudo-random sequence modulation based |
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| CN1773979A (en) * | 2004-11-09 | 2006-05-17 | 华为技术有限公司 | Orthogonal frequency division multiplexing accurate time synchronizing, frame synchronizing and synchronous tracking method |
| WO2006137023A3 (en) * | 2005-06-24 | 2007-03-08 | Koninkl Philips Electronics Nv | Method and apparatus for synchronization in wireless communication system |
| CN101778088A (en) * | 2010-03-12 | 2010-07-14 | 中国科学院声学研究所 | Training sequence frame timing synchronized method based on pseudo-random sequence modulation based |
| CN102143117A (en) * | 2011-03-31 | 2011-08-03 | 福州大学 | Time-frequency synchronization joint estimation method based on multi-carrier receiver of digital television media broadcast (DTMB) system |
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