Timing Synchronization Method of cpfsk Signal at Any Rate

Abstract

The invention discloses an any-rate CPFSK (Continuous Phase Frequency Shift Key) signal timing synchronization method which is implemented according to the following technical scheme: an MSD unit demodulates baseband signals which are subjected to resampling processing, and a feedback signal unit carries out processing on a demodulation result so as to acquire feedback signals; a correlation operation unit carries out a correlation operation on the feedback signals and a leading branch, a real-time branch and a lagging branch of CPFSK signals, and a correlation result is subjected to coherent integration and then sent to a code ring discriminator so as to acquire phase discrimination information; a loop filter filters the phase discrimination information, and a filtering result is sent to an NCO; and a resampling unit adjusts an integration interval under control of output enable signals of the NCO, and the phase of the CPFSK signals is changed, thereby achieving a purpose of timing synchronization. According to the invention, advantages of MSD demodulation are utilized, a likelihood function envelope is detected to acquire a timing error, tracking is carried out on code Doppler by using a delay locked loop, and accurate CPFSK signal timing synchronization can be realized under a low signal to noise ratio.

Description

technical field [0001] The present invention relates to a timing synchronization technology in the wireless communication field, in particular to a method for timing synchronization of an arbitrary rate continuous phase frequency shift keying (Continuous Phrase Frequency ShiftKey, CPFSK) modulated signal based on multi-symbol detection (MSD) decision feedback. Background technique [0002] Continuous Phase Frequency Shift Keying (CPFSK) is a special case of Continuous Phase Modulation (CPM). Different from traditional modulation methods, the CPM modulation signal has no phase mutation at the moment of symbol alternation, which can minimize the spectrum width. At the same time, CPM is still a constant envelope modulation, which is not sensitive to the nonlinear effect of the power amplifier and can greatly save transmission power. [0003] Traditional CPM signals are usually demodulated by differential frequency discrimination. Although this method has a simple structure, it ...

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Problems solved by technology

However, due to the use of local '1' and '0' likelihood detection sequences to detect the received signal separately, the phase detection curve obtained under low SNR is not ideal, and the synchronization performance cannot meet the requirements of MSD demodulation

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