Timing frequency synchronization method based on improved Park frequency domain training sequence

Abstract

The invention discloses a timing frequency synchronization method based on an improved Park frequency domain training sequence. The timing frequency synchronization method comprises the following steps: firstly sending a training sequence before an OFDM data symbol is sent, wherein all the sub carriers of the training sequence in the frequency domain respectively send a pseudorandom real number, and structure of a corresponding time domain training symbol is conjugate symmetric; performing timing synchronization by an FS-Park synchronization method firstly by using the time domain training symbol, then performing estimation on fractional part of frequency offset based on a cyclic prefix in the time domain and performing estimation on integral frequency offset by utilizing cross correlationof the training sequence in the frequency domain, obtaining the total frequency offset, namely the sum of the integral frequency offset and the fractional part of frequency offset, and completing synchronization. The timing frequency synchronization method disclosed by the invention designs a new training sequence, and then a more ideal time domain training symbol structure is obtained; and thenbased on the training sequence and the corresponding time domain training symbol thereof, the integral frequency offset and the fractional part of frequency offset are estimated respectively, 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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