Performance comparison of various ISI cancellation SFBC-OFDM decoders in highly frequency selective channel

The Alamouti coded Space Frequency Block Code (SFBC) based Orthogonal Frequency Division Multiplexing (OFDM) scheme is upon analyzed by assuming that the Channel Frequency Response (CFR) remains constant over Alamouti code period (two adjacent OFDM subcarriers). But when the channel is highly frequency selective, this assumption does not hold good and causes inter-symbol-interferences (ISI). Thus, due to the ISI effect, the simple Alamouti decoder is not sufficient to recover the original transmitted signal from the mixed transmitted signals at the receiver side. In this paper, we have investigated several ISI cancellation SFBC OFDM decoders which include SIC, ZF and DF Finally, the performances of the above decoders are compared on the basis of symbol error rate (SER) in highly frequency selective channel environments.