Design of orthogonal space-time block codes for MIMO-OFDM systems with full diversity and fast ML decoding

In this paper, a design of orthogonal space-time block codes (OS-TBC) is proposed for MIMO-OFDM systems operating in frequency-selective fading channels. By stacking the repeated symbols as entries of an OSTBC matrix, the proposed OSTBC can achieve full diversity in frequency-selective fading channels. Moreover, the ML decoding can be performed separately on each symbol, i.e., single-symbol decoding. Simulation results show that for two transmit antennas the proposed OSTBC can achieve a higher diversity gain than the Alamouti code yet maintaining a single-symbol decoding simplicity.