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Timing synchronous method and device based on frequency domain difference mirror image correlation in LTE (long time evaluation) system
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A technology of image correlation and timing synchronization, which is applied in the field of communication and can solve problems such as increased calculation amount and synchronization signal interference
Inactive Publication Date: 2012-05-23
SHANGHAI RES CENT FOR WIRELESS COMM
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The disadvantages of this method are: (1) Since the index number of the synchronization sequence has not been known, the correlation operation needs to traverse each group of synchronization sequences in the synchronization sequence set, so the amount of calculation increases linearly with the number of synchronization sequence groups in the synchronization set; (2) in In a synchronized cell network, the synchronization signals sent by multiple cells become interference signals with each other
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Embodiment 1
[0043] This embodiment provides a timing synchronization method based on frequency domain differential image correlation in an LTE system. The process of the method is as follows figure 1 shown, including:
[0044] (1) Store the received signal sequence in the time domain.
[0045] The time-domain received signal sequence used for cell search and synchronization is denoted as y(i), i is the index number of the sequence, i=0, 1, 2, ..., T-1, and T is the The number of sample points of the received signal sequence.
[0046] (2) Obtain the frequency domain received signal sequence.
[0047] Perform FFT transformation on the time-domain received signal sequence y(i) to obtain the frequency-domain received signal; record the FFT transformation of K continuous time-domain received signals starting from i as the starting point as Y i (k), wherein, k is the frequency domain received signal Y i(k) subcarrier index, k=0, 1, 2, . . . , N-1, where N is the size of the FFT transform. ...
Embodiment 2
[0062] This embodiment provides a specific implementation process of the method described in the first embodiment. Wherein, the size of the FFT transform is N=64, and the subcarrier index k=0, 1, . . . , 63 of the frequency domain signal. The length of the primary synchronous signal (PSS) is L=62, and the recorded primary synchronous signal sequence is PSS(n), n=0, 1,..., 61, corresponding to the mapping method of the primary synchronous signal in the frequency domain subcarrier Such as figure 2 shown. Wherein, k=0 is a DC subcarrier, and k=32 is an empty subcarrier. image 3 and Figure 4 The 64 time-domain received signal sequences starting from i and the frequency-domain received signal after FFT transformation are given respectively.
[0063] Assume that the time-domain received signal sequence used for cell search stored after the user starts to receive data is y(i), i=0, 1, ... 4800-1, that is, T=4800; it is equivalent to the receiver storing The data of half a wir...
Embodiment 3
[0076] This embodiment provides a device for implementing the timing synchronization method described in Embodiment 1, such as Figure 5 As shown, the device includes a storage module, an FFT transformation module, a frequency-domain differential image correlation module, and a timing synchronization module.
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Abstract
The invention discloses a timing synchronous method and a device based on a frequency domain difference mirror image correlation in an LTE system. The method comprises the following steps of: firstly, receiving and storing a time domain receiving signal sequence which is sent by a base station and used for cell search and synchronization by a mobile user in the LTE system; secondly, performing FFT (fast Fourier transform) for the time domain receiving signal and obtaining a frequency domain receiving signal; thirdly, performing frequency domain difference mirror image correlation for the frequency domain receiving signal and obtaining a mirror image correlation result; fourthly, judging if an obvious peak value interval exists according to the absolute value of the mirror image correlation result, if yes, finding the position of the maximum relative peak according to the absolute value of the mirror image correlation result so as to finish the timing synchronization, otherwise, returning to the first step to detect continuously. The timing synchronous method and the device effectively eliminate the multi-path effect of the time domain, do not depend on a local synchronous sequence, make the synchronous signals sent by a plurality of cells in the synchronous network be available, and improve the accuracy of timing.
Description
technical field [0001] The invention belongs to the technical field of communication, and relates to a timing synchronization method and device based on frequency domain differential image correlation in an LTE system. Background technique [0002] When a mobile user accesses a cell, timing synchronization is required to determine the timing of receiving signals. In order to enable the user to effectively judge the timing of receiving signals, the cellbase station periodically sends synchronization signals, and the set of synchronization signals is known at the base station and the user end. However, the mobile user does not know which group in the synchronization signal set it is before accessing the cell, so the mobile user needs to find an effective method to obtain the timing information of the signal according to the received signal sequence on the premise of knowing the synchronization signal set , to complete the timing synchronization process. [0003] Zadoff-Chu ...
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