Low-Complexity Data-Detection Algorithm in Cooperative SFBC-OFDM Systems With Multiple Frequency Offsets

This paper addresses the problem of data detection in cooperative space-frequency block-coding (SFBC) orthogonal frequency-division multiplexing (OFDM) systems in the presence of multiple carrier frequency offsets (CFOs). A new ordered-successive parallel interference cancellation (OSPIC) detector is proposed. This method consists of first carrying out coarse ordered interference cancellation detection, where the interference components are successively eliminated, and then performing fine interference cancellation detection using parallel interference reduction. Simulation results show that the proposed detector significantly outperforms existing detectors and performs close to that of CFO-free systems for practical signal-to-noise ratios (SNRs). To further reduce the computational complexity, a minimum mean-square error (MMSE)-based reduced-complexity OSPIC (RC-OSPIC) detector is proposed. Compared with the MMSE detector, which requires a full-size complex matrix inversion, the proposed RC-OSPIC detector performs better and is computationally much more effective.