Improved M-part timing synchronization and frequency offset method based on CAZAC sequence

Abstract

The invention discloses an M-part timing synchronization and frequency offset method based on a CAZAC sequence, and the method comprises the steps: dividing the CAZAC sequence to obtain a CAZAC leader sequence meeting conjugate antisymmetry, obtaining a CAZAC training sequence, and obtaining a receiving signal according to the CAZAC training sequence; constructing each timing metric matrix by using a received signal and a CAZAC training sequence, and screening a symbol timing estimation value; performing weighted summation on the symbol timing estimation value to obtain a timing deviation estimation value; meanwhile, according to symbol timing estimation values and conjugate antisymmetry between adjacent symbols, an integer frequency offset estimation value and a decimal frequency offset estimation value are obtained, and finally timing synchronization and frequency offset estimation are conducted through the decimal frequency offset estimation value, the integer frequency offset estimation value and the symbol timing estimation value. According to the invention, by constructing the leader sequence and combining the combination characteristics of the sequence, accurate and stable timing synchronization can be realized, the problem of timing and frequency offset joint synchronization in a satellite-ground large dynamic environment is solved, the symbol estimation and frequency offset performance is improved, and the anti-noise interference capability is improved.

Description

technical field [0001] The invention relates to the technical field of satellite communications, in particular to an improved M-part timing synchronization and frequency offset method based on a CAZAC sequence. Background technique [0002] CAZAC sequence is the abbreviation of constant envelope zero autocorrelation sequence, which is widely used in the synchronization algorithm of OFDM system. For example, in the terrestrial cellular mobile communication system, LTE uses the ZC sequence in the CAZAC sequence as the primary synchronization sequence. CAZAC has the characteristics of constant envelope, ideal periodic autocorrelation, and good cross-correlation. Common CAZAC sequences include ZC sequence, Chirp-Like sequence, Colomb sequence and Frank sequence, etc.; [0003] The fourth-generation communication system mainly uses the ZC sequence as the main synchronization sequence, which has a good autocorrelation peak under the condition of low signal-to-noise ratio. However...

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Problems solved by technology

[0004]Aiming at the above-mentioned deficiencies in the prior art, the present invention provides an improved M-part timing synchronization and frequency offset method based on CAZAC sequences, using specific training symbols The time domain structure, combined with the improved CAZAC sequence, solves the problem of downlink timing and frequency offset synchronization in the large dynamic environment of the satellite and the ground, and improves the ability to resist noise interference

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