System and method for realizing iterative timing synchronization of continuous phase modulation signal

Abstract

The invention discloses a system and a method for realizing iterative timing synchronization of a continuous phase modulation (CMP) signal; the system is provided with a sender, and is composed of a maximum likelihood detector, a de-interleaver, a channel decoder and an information destination which are connected in order, and an interleaver which is used for interleaving an output signal of the channel decoder and feeding back the interleaved output signal to the maximum likelihood detector; a built-up circuit of the maximum likelihood detector comprises a match filter set, a demodulator, and a timing synchronization loop circuit arranged between the match filter set and the demodulator; a detecting method based on a maximum likelihood criterion is used for demodulating the received CPM signal, detecting and computing a timing error value and adjusting the time delay, and outputting a bit likelihood ratio of each symbol. Based on a timing error detecting method of the maximum likelihood criterion, a soft information assistance fed back by the channel decoder is used for realizing the timing synchronization to obtain an accurate timing deviation estimation; meanwhile, an iterativeprocess is used between the demodulation and the decoding to maximally improve an error bit ratio of the system; and the system and method for realizing iterative timing synchronization of the CMP signal can be applied in long-distance communication with the requirement of high performance.

Description

technical field [0001] The present invention relates to a system and method for realizing iterative timing synchronization of a continuous phase modulation CPM (Continuous phase modulation) signal, which is used to solve the problems of time delay estimation, time offset correction and clock jitter in the digital communication system of continuous phase modulation , belonging to the technical field of digital communication. Background technique [0002] Timing synchronization is an important part of digital communication. Although there are many discussions about linear modulation timing methods, there are very few literatures describing synchronization algorithms for nonlinear continuous phase modulation signals. [0003] see figure 1 , introduces the structure of the traditional CPM digital communication system, where t is the system time, and the received signal at the receiving end is r(t). The timing synchronization loop circuit in the figure is used to calculate the...

AI Technical Summary

Problems solved by technology

[0013] In view of this, the object of the present invention is to provide a system and method for realizing iterative timing synchronization of continuous phase modulation signals, which are used to solve the time delay estimation and time offset correction in the continuous phase modulation CPM digital communication system, and the clock in the system Jitter problem, so as to improve the signal-to-noise ratio threshold of the synchronous loop under low signal-to-noise ratio conditions, and thus increase the signal-to-noise ratio threshold for the normal operation of the system

Images