Ofdm Transmission System, Channel Estimation

Orthogonal Frequency Division Multiplexing(OFDM) is regarded as the core technology of the next generation mobile communication and now become a hot research in the field of communications. But,Receiving system can get the transmitter signal correctly, Channel estimation is one of the key technology. The Channel estimation has directly impact on the performance of the entire system.This paper mainly research the Channel estimation algorithms of the OFDM system. Channel estimation algorithm has been divided two aspects: One is the Pilot-based algorithm and the other is blind channel estimation algorithm based on Sub-space Decomposition. In performance, the former is obviously better than the latter. And the channel estimation of the Pilot directly affect the accuracy of the sub-channels estimation. Channel estimation include MMSE algorithm, LS algorithm, ML algorithm. The MMSE and ML are significantly higher than LS in the computational complexity and the Higher Order spectrum can be completely eliminated the white Gaussian noise, in theory. So,this paper introduce a Higher Order spectrum-based channel estimation algorithm to improve the accuracy of the channel estimation. Simulation results show the effectiveness of the algorithm.