Low signal-to-noise ratio short frame burst communication open loop demodulation method and device

Abstract

The invention discloses a low signal-to-noise ratio short frame burst communication open loop demodulation method and a low signal-to-noise ratio short frame burst communication open loop demodulationdevice, and belongs to the technical field of direct sequence spread spectrum demodulation technologies. According to the method, a segmented data processing mode is used for firstly demodulating dispreading data, then performing supply-zero FFT to estimate a frequency offset variation rate and frequency offset and perform compensation. A method of exhaustion is used for accurately estimating andcompensating each frequency offset, the polarity of a frame header is used for performing defuzzification on the phase, to complete correct demodulation of the data. Compared with the prior art, themethod and the device provided by the invention overcome the disadvantages that traditional phase-locked loop coherent demodulation devices are fuzzy in phase and slow in convergence speed, the frequency offset and the frequency offset variation rate can be quickly searched and compensated, the phase discrimination and phase correction can be completed, the short time is ensured, and a direct sequence spreading signal can be normally demodulated under the condition of a low signal-to-noise ratio.

Description

technical field [0001] The present invention relates to a carrier phase tracking and coherent demodulation method (hereinafter referred to as the demodulation device), in particular to a low signal-to-noise ratio short-frame burst communication open-loop demodulation method and device, suitable for high dynamics, low signal-to-noise ratio, etc. The invention relates to open-loop search, tracking and symbol coherent demodulation of carrier frequency offset and frequency offset change rate of short-frame burst direct sequence spread spectrum system in the environment, belonging to the field of demodulation technology in direct sequence spread spectrum communication. Background technique [0002] The communication between high-speed aircraft and ground equipment or high-speed aircraft has the characteristics of long communication distance, large link attenuation, and low signal-to-noise ratio, so the direct sequence spread spectrum communication system is often used; and this ki...

AI Technical Summary

Problems solved by technology

[0025] Traditional BPSK coherent demodulation modules usually use phase-locked loops, such as square loops, Costas (Costas) loops, etc., to achieve carrier tracking, but they cannot effectively solve the "inverted π" problem, that is, the restored local carrier and the required The coherent carrier wave may be in the same phase or reversed. This phase uncertainty will cause the demodulated digital baseband signal to be just opposite, and the judged digital symbols will all be wrong.

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