Hybrid spread spectrum communication system based on low density parity code (LDPC) encoding and method thereof

Abstract

The invention discloses a hybrid spread spectrum communication system based on low density parity code (LDPC) encoding and a method thereof. The problems of leakage capture, high leakage capture probability, slow convergence of a phase-locked loop and low decoding performance of the existing synchronous capture method are mainly solved. The system comprises a transmitting part and a receiving part, wherein the transmitting part is used for carrying out pretreatment on original information; the pretreatment data are subjected to frequency hopping treatment and transmitted after being modulated and filtered by a base band; the receiving part is used for obtaining a synchronization point position and a frequency offset value in the received signal through synchronous capture, and intercepting useful data to carry out de-hopping according to the synchronization point position; the base band demodulates and filters; the filtering data are subjected to frequency offset compensation according to the frequency offset value; the data after frequency offset compensation are subjected to dispreading and frequency offset rectification; the frequency offset rectification data are decoded and the decoding result is output. The hybrid spread spectrum communication system has the advantages of being strong in burst error resisting ability, high in real-time synchronization capture speed, high in capture accuracy, high in convergence speed of the phase-locked loop, and good in decoding performance, and can be applied to reliable communication under the condition of very low powder spectral density.

Description

technical field [0001] The invention belongs to the technical field of communication, and further relates to a direct sequence spread spectrum and frequency hopping hybrid spread spectrum communication method in wireless communication, which can be used for coding, modulation, transmission and reception, demodulation, and decoding of wireless signals in a wireless communication system. Realize ultra-wideband fast frequency hopping and reliable communication under extremely low power spectral density. Background technique [0002] Spread spectrum communication technology, referred to as spread spectrum communication, is a broadband communication method. The data to be sent is spread to a wide frequency band by using a pseudo-random PN sequence and then transmitted. At the receiving end, the same pseudo-random sequence as that at the transmitting end is used. Perform relevant processing to restore the original data. Spread spectrum includes direct sequence spread spectrum DS,...

AI Technical Summary

Problems solved by technology

[0006] 1. The synchronous capture method misses capture and has a high probability of wrong capture;

[0007] 2. The implementation of the phase-locked loop is complex, and the convergence of tracking mixed spread spectrum signals is slow;

[0008] 3. The short code of the hybrid spread spectrum communication channel is easily affected by the channel environment, and the decoding performance is low

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