Performance of differential space-frequency modulation under time-varying frequency-selective fading channels
In this paper two differential subcarrier grouping schemes named MSSG and SSSG are firstly analyzed under the same mathematic model. Then we describe two differential space-frequency modulation schemes combining differential space-time modulation and orthogonal frequency division multiplexing. They are F-DSFM in which differential encoding is carried out in frequency direction and T-DSFM in which differential encoding is carried out in time direction. Analysis and simulation results show that F-DSFM is suit for strong time- selective fading channels and T-DSFM is suit for strong frequency-selective fading channels, under time-varying frequency-selective channels subcarrier grouping scheme SSSG is better than MSSG especially for low data rate transmission.