A Timing Frequency Synchronization Method Based on Improved Park Frequency Domain Training Sequence

Abstract

The invention discloses a timing and frequency synchronization method based on an improved Park frequency domain training sequence. Before OFDM data symbols are sent, a training sequence is sent first. The training sequence transmits pseudo-random real numbers in all sub-carriers in the frequency domain, and the corresponding The time-domain training symbol structure has conjugate symmetry. The FS-Park synchronization method first uses the time-domain training symbols for timing synchronization, and then performs fractional frequency offset estimation based on the cyclic prefix in the time domain, and uses the cross-correlation of the training sequence in the frequency domain. The integer frequency offset is estimated, and the total frequency offset is obtained as the sum of the integer frequency offset and the fractional frequency offset, and the synchronization is completed. The present invention designs a new training sequence so as to obtain an ideal time-domain training symbol structure. Then, based on the training sequence and its corresponding time domain training symbols, integer multiples and fractional multiples of frequency offsets are respectively performed, and timing synchronization estimation is performed.

Description

technical field [0001] The invention belongs to the technical field of OFDM system synchronization, and in particular relates to a timing frequency synchronization method based on an improved Park frequency domain training sequence. Background technique [0002] As the core technology of 4G, Orthogonal Frequency Division Multiplexing (OFDM) is a multi-carrier transmission technology that divides the entire frequency band into multiple orthogonal sub-carriers to combat frequency selective fading and improve frequency band utilization. At the same time, it is extremely sensitive to timing and frequency offset. On the one hand, the carrier frequency offset caused by the Doppler effect or the difference between the local carrier frequencies at the two ends is usually compensated by carrier synchronization; on the other hand, the timing offset caused by the difference The rotation of the carrier phase is caused, and timing synchronization can be used to determine the start and e...

AI Technical Summary

Problems solved by technology

Then, based on the training sequence and its corresponding time-domain training symbols, integer multiples and fractional frequency offsets are respectively performed, and timing synchronization estimation is performed. By sending pseudo-random real numbers in each subcarrier in the frequency domain, a conjugate symmetric The structured training symbol effectively solves the problem of large secondary peaks around the main peak in the Park method, and the frequency offset estimation range reaches -N / 2~N / 2

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