Performance evaluation of MIMO-OFDM system based on time-switched transmit diversity

In this paper,a time-switched space-time(TSST) coded orthogonal frequency division multiplexing(OFDM) scheme against the time-varying channels is proposed.In the TSST-OFDM scheme,it is equipped with four transmit antennas,but only double of them are used for coding in every time slot.It is shown that the signal to inter-antenna interference ratio is a function of Doppler frequency in time-varying channels for a given space-time code.The analyses and simulations results validate that the proposed scheme not only gets timeswitched diversity and lower decoding complexity,but also suffers less time-varying impairments.Hence,it exhibits better performance than quasi-orthogonal space-time coded scheme.