Data Detection in Cooperative STBC-OFDM Systems With Multiple Frequency Offsets

This paper addresses the problem of data detection in cooperative space-time block coded (STBC) orthogonal frequency division multiplexing (OFDM) systems in the presence of multiple carrier frequency offsets (CFO). An enhanced iterative maximum-likelihood detector (EIMLD) is proposed. This method consists of first removing inter-carrier interference (ICI), and then performing iterative symbol detection and inter-symbol interference reduction. Simulation results show that EIMLD significantly outperforms existing iterative methods. Comparisons with the zero-forcing and minimum-mean square error detectors, which require complex matrix inversion, are also carried out.