Time-frequency double differential space-time coding for MIMO-OFDM systems

Differential space-time modulation has been proposed recently in the literature for multiple-antenna systems over Rayleigh fading channels, where neither the transmitter nor the receiver knows the fading coefficients. Among existing schemes, double differential space-time (DDST) coding is of special interest because it is applicable to continuous fast time varying channels. However the performance of DDST degrades considerably in frequency-selective channels. A novel time-frequency double differential space-time coding scheme is proposed for multi-antenna orthogonal frequency division multiplexing (OFDM) system, which is robust for time-varying frequency-selective Rayleigh fading channels. The new coding scheme adopts the double differential coding method in both time and frequency domains. A corresponding suboptimal yet low-complexity non-coherent detection approach is also proposed. System performance is evaluated with simulations.