Carrier synchronizer for demodulating low signal-to-noise ratio burst signals

Abstract

The invention discloses a carrier synchronizer for demodulating low signal-to-noise ratio burst signals. The carrier synchronizer comprises an input cache module, an initial frequency deviation estimation module, a frequency deviation partition preset module, N two-way capture tracking modules, N unwrapping phase ambiguity and soft de-mapping modules, an iterative decoding module and an optimal judgment module. Each two-way capture tracking module corresponds to one unwrapping phase ambiguity and soft de-mapping module. Initial frequency deviation is estimated based on preceding heads of the burst signals, then, after an initial frequency deviation estimation result is preset in a partition mode, two-way capture tracking is utilized to conduct carrier synchronization, the optimal judgment module selects an optimal carrier to conduct synchronous output according to judgment soft information statistical values output by the iterative decoding module, and eventually the iterative decoding module conducts decoding on the carrier and outputs a final result. By the adoption of the carrier synchronizer, optimization design is conducted on burst signal carrier synchronization under the low signal-to-noise ratio, and the problem of low signal-to-noise ratio carrier synchronization of TDMA system communication is solved.

Description

Technical field

[0001] The invention discloses a carrier synchronizer for demodulating burst signals with low signal-to-noise ratio. Background technique

[0002] The core issue in the demodulation of burst signals with low SNR is carrier synchronization. Carrier synchronization methods can be divided into feedback type closed-loop carrier synchronization and feedforward type open-loop carrier synchronization. For burst signal demodulation, traditional feedback-type closed-loop carrier synchronization has problems such as long acquisition time and “hanging”, which cannot meet application requirements well. Therefore, open-loop carrier synchronization methods based on parameter estimation are generally used. The adaptive signal-to-noise ratio range of open-loop carrier synchronization is mainly limited by the parameter estimation accuracy, and the parameter estimation accuracy depends on the estimation algorithm and the length of the preamble used for estimation. However, under ...

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