Research On Synchronization In Mobile Multimedia Broadcasting System Based On OFDM

This paper makes a deep research on the timing and frequency synchronization technology in wireless OFDM receiver under frequency selective and time selective fading channels.First, the development of mobile multimedia broadcasting technology worldwide is introduced briefly, followed by the summarization of the basic idea and mathematical principles of OFDM technology. Then the basic characteristics and key parameters of wireless channel model are discussed. With the aid of coherent demodulation and digital signal processing theory, the influences of symbol timing, carrier frequency and sampling clock offset to wireless OFDM system are analyzed in detail. In the study of China Mobile Multimedia Broadcasting system, two improved symbol timing and carrier synchronization algorithms with high efficiency are proposed based on its specific frame structure and existed timing and frequency synchronization algorithms in traditional OFDM system, which gain better correlation results than traditional algorithms. All the algorithms in this paper are simulated and compared sufficiently with Matlab and the simulation results show that the proposed algorithms are robust under frequency selective and time selective fading channels. Finally, taking the practical physical layer transmission control mechanisms into account, a total solution is proposed to the whole architecture for the timing and frequency synchronization module in CMMB system receiver, which is tested and verified by demodulating data acquired in field test. The test results show that the proposed architecture is suitable for CMMB system in burst transmission mode and mobile reception condition.