High Effective MAP Algorithm for MIMO-OFDM Systems

For MIMO-OFDM systems, maximum a posteriori probability (MAP) channel estimation algorithm induces large matrix inversion and product operation when it is applied to multiple-input multiple-output with orthogonal frequency division multiplexing (MIMO-OFDM) systems. And the data transmission efficiency will be reduced with the increasing number of transmit antennas. According to these problems, a high effective MAP algorithm for MIMO-OFDM is proposed. This algorithm which uses the characteristic of Expectation maximum (EM) algorithm decrease high complexity. To improve the data transmission efficiency and the performance of channel estimation, joint estimation is carried out over multiple OFDM symbols. Besides, depending on the spatial independence of MIMO channel in angle domain, the dimension-reduced MAP algorithm will be enhanced. Simulation results indicate the proposed algorithm obtains better the performance of estimation and higher data transmission efficiency.