MIMO-OFDM with pilot-aided channel estimation for WiMax systems

This paper describes a channel estimation scheme for Multiple Input Multiple Output (MIMO)-Orthogonal Frequency Division Multiplexing (OFDM) systems based on training sequence. We first develop an approach to channel estimation which is crucial for the decoding of the transmitted data. We then discuss the implementation of the proposed method for WiMax systems under various channel conditions. The efficiency of the new algorithm is demonstrated through the simulation of the MIMO-OFDM system for two and four transmit antennas and different number of receive antennas. The Space-Time Coding with 192 information subcarriers per codeword is used as defined in the WiMax standard. Through simulations, it is shown that the proposed method has between 1.5 dB and 2dB loss compared to the ideal case where the channel coefficients are known at the receiver. In summary, with the proposed channel estimation technique, combining diversity using Space-Time Codes with OFDM is proved to be a promising technique for the present and future wireless communications.