The Research Of Sychronization Technology In Digital Receiver

Synchronization is a challenging and very important task in digitalcommunication. In digital communication system, a hierarchy of synchronizationproblem has to be considered, whether communication systems can work validly andreliably or not depends on synchronization technology, so it is a key technology incommunication system. This paper deals with the estimation and adjustment of carrierfrequency offset, phase error and symbol timing error, then completessynchronization in the digital receiver according to the research work's actual needs.The synchronization technology in the digital receiver is introduced in this paperfirstly, including carrier synchronization and symbol synchronization.Synchronization algorithm mainly includes two kinds: opened loop algorithm andclosed loop algorithm. Then, the author studies some typical carder synchronizationalgorithm and symbol synchronization algorithm.This paper aims to researching appropriate synchronization scheme for thedigital receiver and putting forward synchronization algorithm based on thepredecessor's achievement. The main job and contribution of this paper contains suchaspects as follows:1. The dissertation has studied the appropriate digital receiver signal model, andtestified the importance of synchronization technology in the digital receiver.2. The dissertation puts forward a new carder synchronization algorithm basedon adaptive step. In order to solve the Maximum Likelihood(ML) estimationalgorithm's non-linear optimization problem, this new algorithm is designed,combined with particle swarm optiminzalton algorithm(PSO). The algorithm cansearch and realize the estimation accurately.3. In terms of symbol synchronization algorithm, in order to solve the symbolsynchronization problem of the changing symbol rate communications system, thepaper presents a symbol rate adaptive synchronization scheme, a new scheme whichcombined with symbol rate estimation using wavelet transform is designed. Theauthor also constructs its realization diagram, and then simulated the key modules. 4. The paper constructs an integrity synchronization simulation system withMATLAB, specified the whole process from signal model production tosynchronization system output simulation ,which provides a very useful MATLABsimulation platform for studying the synchronization algorithm in digital receiver.5. The paper introduced the hardware debug platform for synchronizationalgorithm in detail, and the platform is a digital receiver which is designed based onconcept of software radio. The digital receiver function includes: frequency scanning,specified frequency signal interception, identification and demodulation, whichprovides reference for the digital receiver hardware design.