A Time Synchronization Method Based on Autocorrelation and Differential Correlation
A differential correlation and time synchronization technology, applied in the field of time synchronization, time synchronization based on autocorrelation and differential correlation, can solve the problems of loss of performance gain, reduction of synchronization sequence length, etc.
Active Publication Date: 2016-11-30
RUN TECH CO LTD BEIJING
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[0008] Although the performance of the classic piecewise correlation autocorrelation method is better than that of the direct autocorrelation method in the middle and high frequency partial scene, and the performance is only reduced by about 3dB compared with the latter in the low frequency partial scene, due to the piecewise correlation, artificial Reduced synchronization sequence length, thus losing performance gain
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[0095] The flow chart of the present invention sees in detail Figure 18 , the operation steps are as follows:
[0096] 1. Rotate the local synchronization sequence l to the right by N d Bit or head padding N d zero, get l_off; here N d It is a variable parameter, ranging from 0 to L / 2, and can be preset to L / 4. It can also be determined by the application scenario. The larger the frequency offset, the larger the value should be; L is the length of the local synchronization sequence 1.
[0097] 2. Intercept a sequence r1 of length L from the head of the received data (sequence to be synchronized) of length P;
[0098] 3. Carry out the conjugate point multiplication of r1 and the local sequence l and then sum (conjugate point multiplication and summation is correlation) to obtain corr1;
[0099] 4. From the received data from N d Intercept the sequence r2 of length L;
[0100] 5. The conjugate point multiplication of r2 and the local sequence l_off is summed to obtai...
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The invention discloses a time synchronization method based on autocorrelation differential correlation. This method is: 1) The receiving end shifts the local synchronization sequence l of length L to the right by N d and generate a sequence l_off of length L; 2) Intercept the sequence r1 of length L from the head of the sequence to be synchronized and correlate with sequence l to obtain corr1; 3) From the Nth sequence of the sequence to be synchronized d Correlate the sequence r2 with length L and sequence l_off to get corr2; 4) correlate corr1 and corr2 to get the correlation result of the first point of the sequence to be synchronized; 5) shift the sequence to be synchronized to the right by 1 bit at a time to update sequence r1 , r2; then the correlation calculation updates corr1 and corr2 and calculates the correlation results of the remaining points; 6) Select a number of points whose correlation results are greater than the set threshold or the maximum as the synchronization points for verification, determine the synchronization sequence, and time the sequence to be synchronized Synchronize. The invention has strong adaptability and high performance gain.
Description
technical field [0001] The present invention relates to a time synchronization method, in particular to a time synchronization method based on autocorrelation differential correlation; it belongs to the field of communication, especially the field of wireless communication Background technique [0002] In current communication systems, it is often necessary to perform time-domain auto / cross-correlation processing on data to determine synchronous data. Usually time synchronization is to perform auto / cross-correlation processing on the known sequence. The known sequence here refers to the synchronization sequence, that is, the known information (synchronization sequence) and communication data are sent, and the received sequence is the sequence to be synchronized. The correlation between the local sequence and the synchronization sequence contained in the sequence to be synchronized needs to be used for synchronization. [0003] The current basic principles of time synchroniz...
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IPC IPC(8): H04L7/00
Inventor 周维邓敬贤李锡忠
Owner RUN TECH CO LTD BEIJING