Research On Synchronization Algorithms Of Distributed MIMO-OFDM System

Because OFDM can change frequency selective channel into parallel narrow band channels, making channel equalization simple, and MIMO can compensate for the defect of high bit error rate created by the OFDM in the deep fading channel. The conbination of MIMO-OFDM , which can increase data transmission rate and system reliabiligy, is expected to to become the core technology B3G/4G.This paper first introduces the basic principles of OFDM and MIMO.Based on it,This paper gives a detailed analysis of MIMO-OFDM and its key technologies, analyzes the common method to resolve the variety of MIMO-OFDM synchronization error, and gives the MIMO channel model.The technology of synchronization is the primary problem in any MIMO- OFDM cellular system. Resoving the synchronization of MIMO-OFDM ,we need to study the effects on the system performance caused by the various synchronization error. Under the premise of providing the MIMO-OFDM system model, this paper gives a detailed analysis of the impacts on the system performance, which are produced by timing within the FFT window, timing within the cyclic prefix and the carrier frequency offset and the MSIR to quantify the synchronization error.In the distributed MIMO-OFDM system, due to the different timing offset and frequency offset between transmittiong antenna and receiving antenna, then the primary mission of synchronization is to estimate every timing offset and frequency offset between transmitiong antenna and receiving antenna simultaneously. This paper based on the basic idea that conjugate symmetry train sequence could improve the precise estimation of timing and frequency offset, propose a algorithm using partitioned conjugate symmetry train sequence weighted by pseudorandom sequence to resolve the time and frequency synchronization. Via using the technology of receive diversity and iterarive processing, the performance of estimation of frequency offset could be improved ulteriorly. The algorithm could simultaneously estimate the time and frequency offset every antenna pair.