Study On Carrier Synchronization In Burst Mode Communication

Burst mode transmission is characteristic of short signal duration and long time interval. Is is a communication mode that is being widely adopted, of which carrier synchronization is a key technology. In the communication process, the output instability of local oscillator and temperature drift, as well as the doppler shift resulting from the relative motion between mobile stations and base stations, are to causing large carrier frequency offset. As the communication technologies rapidly developing, the space electromagnetic environment becomes more complex, filling channels with different kinds of signals, which has a negative effect on normal transmissions. The purpose of this paper, is to discuss the impact of narrowband interference on carrier synchronization, and to come up with an effective algorithm aiming at the problem.First, as a base for the next chapters, the classification of carrier recovery algorithoms and several performance indexes for algorithm evaluations are introduced. Then, the open-loop feedforward carrier synchronization methods are discussed, which includes data-aided(Kay, Fitz, M&M etc.), non data-aided(AR spectrum estimation) and code-aided(EM). Also, the estimation range and accuracy of some of the above algorithms are simulated and analysed. At last, the influnce of narrowband interference on carrier synchronization is investigated, leading to the conclusion that some classic estimation schemes do not work well in the presence of such interference. So a novel carrier synchronization method, which is based on specially designed training sequence and spectrum analysis, is raised against the jamming signal. The new algorithm is featured with a feedforward structure, which is easy for digital implementation, and has a reletively wide estimation range and satisfactory estimation accuray, thus successfully overcoming the impacts of the narrowband interference on freqency offset estimation.