A demodulation method and system for dynamic threshold judgment based on qpsk modulation with frame synchronization code implicit in information code

Abstract

The present invention is a demodulation method and system based on the dynamic threshold judgment of QPSK modulation that the frame synchronization code is implicit in the information code, which is different from the fixed format of the synchronization symbol plus the data symbol of the traditional data frame. Sequencing is implicit in the modulation and demodulation process. When modulating at the sending end, the amplitude of the signal is modulated by using the synchronization code sequence, so that the synchronization code sequence is implied in the information sequence. When demodulating at the receiving end, the signal corresponding to the synchronization code sequence is extracted from the received signal, and the method of correlation detection can be used to realize the frame synchronization of the system. After the synchronization is achieved, the received signal is coherently demodulated, and a dynamic threshold judgment The method makes a judgment and restores the original information bits. The transmission rate of the system is improved by embedding the frame synchronization code in the modulation, and the dynamic threshold judgment is used in the demodulation to improve the bit error rate performance of the demodulation.

Description

technical field [0001] The present invention is a demodulation method and system for dynamic threshold judgment based on frame synchronization code implicit in QPSK modulation of information code, which belongs to the technical field of wireless communication, and relates to a method for efficient transmission and demodulation of information code, and the specific content is frame synchronization code The dynamic threshold judgment method of QPSK modulation implicit in the information code ensures that the transmission system achieves a lower bit error rate and improves the reliability of communication. Background technique [0002] In a digital time division multiplex communication system, in order to correctly separate the signals of each time slot, the start mark of each frame must be provided at the sending end, and the process of detecting and obtaining this mark at the receiving end is called frame synchronization. There are two types of frame synchronization: start-st...

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Problems solved by technology

The frame synchronization code is implicitly transmitted in the information code to improve the utilization rate of channel resources; in the demodulation, the information of the frame synchronization code is fully utilized to dynamically adjust the judgment threshold, which solves the problem of poor bit error rate performance when judging under a fixed threshold The problem

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