Symbol timing method and system of continuous phase modulation signals

Abstract

The invention provides a symbol timing method and system of continuous phase modulation signals. The method comprises the following steps: S1, setting N counters, which separately correspond to N sampling moments of a code element period, wherein N represents a sampling point number of each code element; S2: obtaining sampling data of an I path and a Q path of signal waveforms of baseband data of the continuous phase modulation signals, and judging whether the I path and the Q path of signal waveforms have monotonicity at each sampling moment, and if not, performing definite value accumulation on the corresponding counters; and S3: after a certain sampling time, comparing the count values of the N counters, and using the sampling moment corresponding to the maximum numerical value as a starting moment of the code element. The symbol timing method and system of continuous phase modulation signals provided by invention have the advantages that the computational burden is small, and that the precision satisfies the optimal demodulation requirements.

Description

technical field [0001] The present invention relates to the field of communication technology, in particular to a symbol timing method and system for continuous phase modulation signals. Background technique [0002] Minimum shift keying (MSK) and Gaussian minimum shift keying (GMSK) are continuous phase modulation (CPM) with a modulation index of 1 / 2, where the MSK frequency impulse response is a rectangular pulse, and the GMSK frequency impulse response is a Gaussian minimum frequency shift keying pulse. MSK / GMSK has a constant envelope and continuous phase, which makes its out-of-band radiation power small and its spectral density concentrated, and because its phase has memory, it has a certain error correction capability. Therefore, MSK / GMSK has higher frequency band utilization and higher power utilization, and is suitable for transmission in wireless communication channels. MSK has become a main modulation method in the Link16 data link of the United States because o...

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Problems solved by technology

[0004] The literature "Vitetta Joint Phase and Timing Recovery With CPM signals." (Michele Morelli, Umberto Mengali and Giorgio M.IEEE Trans.Commun, 1997; 45(7)) jointly estimates carrier phase and symbol timing based on the maximum likelihood algorithm , however, the algorithm has high complexity and a large amount of computation

The literature "A GMSK bit synchronization algorithm for DSP realization." (Lai Wenqiang, Zhao Jianye. Radio Engineering, 2004; 34 (2)) Aiming at the all-digital GMSK differential demodulation receiver, a timing synchronization method with simple structure is proposed. But when "0" and "1" are not equal, the performance will drop

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