Turbo Frequency Domain Equalization for Single Carrier Space-Time Block Coded Transmissions

In this paper, we propose a linear minimum mean square error (MMSE)-based turbo frequency domain equalization (FDE) scheme for single carrier space-time block coded (STBC) transmissions. In the proposed iterative receiver, FDE is performed for each individual tone after space-time (ST) decoding and exchanges extrinsic information with the soft in soft out (SISO) decoder according to the turbo principle. Due to the tone-wise equalization, no matrix inversion is required in the computation of the FDE weight coefficients compared to the conventional turbo FDE and resulting in a lower complexity. We also consider an approximate implementation of the proposed scheme suffering from little performance loss in exchange for further complexity reduction. The simulation results demonstrate that high performance improvement can be obtained using the proposed iterative scheme compared with the non-iterative one.