Space-time-frequency block coding over Rayleigh fading channels for OFDM systems

In this paper, a novel space-time-frequency code scheme - bit-interleaved space-time-frequency block coding (BI-STFBC) - being fit for OFDM system is considered for frequency-selective Rayleigh fading channels. Incorporating subcarrier grouping and choosing appropriate system parameters, we convert out system into a set of group STF (GSTF) system, within which STF coding is considered. Code bits are bit-wise interleaved across every grouping subcarrier before being grouped and mapped to space-time-frequency code, followed the unitary constellation-rotating precodes. The spectral efficiency and pairwise error probability (PEP) are also considered. Comparing with the existing alternatives, the proposed scheme can attain maximum diversity with low decoding flexibility. Simulation results confirmed the effectiveness of the proposed scheme.