Research Of Timing Synchronization Technology In High-rate Data Transmission System

Timing synchronization is the process of extracting symbol timing informationfrom received baseband signals, which is a key technology in communication systems.In modern digital communication systems, a good timing synchronization algorithmshould have both high efficiency and high precision these two advantages. In practicaldigital communication systems, especially in satellite communication systems,Multiple Phase Shift Keying (MPSK) and Continuous Phase Modulation (CPM) aretwo widely used modulation technologies. This is because the former can achievehigh-rate data transmission and has a good performance in anti-jamming, and the latercan offer power and bandwidth efficiency advantages. Since these two modulationtechniques have been widely studied and used in satellite communication systems,which promotes the research of their synchronization technology. This paper is justbased on the above background, and it mainly studies the timing synchronizationalgorithm which applies to MPSK signals and CPM signals.In this paper, first, it describes the basic principle of satellite communications andtiming synchronization technology, after that the features of both feedback andfeedforward algorithms are given respectively. Among them, feedback algorithms hasgood performance in tracking timing information, eliminating timing jitter andreducing system overhead and the features of feedforward algorithms are: no feedbackloop, fast capture and short synchronized time. For MPSK signals, the article mainlystudies the Gardner timing synchronization algorithm which is based on the structureof phase-locked loop (PLL). In the final part of chapter III, the paper investigatesGardner algorithm’s performance in QPSK system and TCM8PSK system by computersimulation. For CPM signals, the article first briefly introduces several typical timingestimation algorithms. Then, it concentrates on a data aided algorithm with joint timingsynchronization and carrier frequency offset estimation which based on feedforwardstructure, and this algorithm can be applied to a mixed receiver for GMSK signals. Thereceiver can demodulate not only non-coherent signals, but also coherent signals. Inthe final part of chapter IV, the paper gives the acquisition performance of this GMSKreceiver through computer simulation.