Carrier synchronization system and method of combining pilot frequency and iterative decoding

Abstract

The invention discloses a carrier synchronization system and a method of combining pilot frequency and iterative decoding. The system comprises a Turbo coding module, a multiplex module, a modulation module, a carrier estimation module, a demodulation module and an extension Turbo decoding module. The method includes the steps of receiving sequences, initial estimation, correcting signals, quadrature phase shift keying (QPSK) demodulation, data demultiplexing, Turbo decoding, hard decision, decoding termination conditions, data multiplexing, QPSK modulation and fine estimation. The carrier synchronization system and the method of the combining the pilot frequency and the iterative decoding have the advantages that the defect that in prior art, the frequency estimation accuracy is low caused by the fact that pilot frequency with the same number and maximum likelihood algorithm are utilized is overcome, the carrier frequency estimation accuracy is improved, simultaneously the disadvantage that in prior art, the output of a Turbo decoder is required to be recoded or subjected to nonlinear transformation is overcome, and the algorithm complexity of combining Turbo decoding and carrier synchronization process is reduced.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and further relates to a carrier synchronization system and method of joint pilot and iterative decoding in the technical field of channel coding. In the fields of military communication, satellite communication, telemetry communication and the like, the invention can realize carrier recovery by means of the soft information output by the iterative decoder in the pilot frequency and encoding system, and ensure the reliability of communication. Background technique [0002] In recent years, due to the high coding gain and low working threshold of Shannon limit codes such as Turbo codes and Low Density Parity Check codes, they have been paid attention to, but their excellent performance can only be reflected under precise synchronization conditions. However, under conditions of low SNR / very low SNR and large frequency offset, in order to correctly decode Shannon limit codes such as T...

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the initial estimation only uses the two pilots before and after for phase estimation, which leads to the fact that under the condition of large frequency offset, the estimation accuracy requirement of decoding cannot be met, so only a small range of frequency offset can be corrected (ΔfT s ≤7×10 -4 ), and at the same time, it is necessary to re-encode the information after the test judgment, which has a high complexity

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