An SFBC-OFDM Receiver to Combat Multiple Carrier Frequency Offsets in Cooperative Communications

In this paper, a new space-frequency combination technique is proposed for Alamouti coded Orthogonal Frequency Division Multiplexing (OFDM) in the context of cooperative communications. Since cooperative antennas are distributed, there may exist multiple carrier frequency offsets (MCFOs) which cause problems for conventional space-frequency decoding. The proposed algorithm, taking cues from existing MCFO-compensating algorithms [13][19], combines two sets of separately synchronized signal to mitigate inter-carrier interference (ICI). Iterative interference cancellation and a maximum-ratio-combining-like technique are also deployed to further improve performance with low computational complexity. It is observed that the proposed method achieves better bits error rate (BER) performance and has a superior tolerance of multiple CFOs, compared to existing methods.