Efficient Block Square-Root Adaptive Equalization for STBC and Diversity Combining Systems

In this paper, a weighted space-time block-coding (STBC)-like matrix-wise block adaptive frequency-domain equalization (WSB-FDE), which has a flexibility over the STBC-like matrix-wise block length as compared to a normalized least- mean-square (NLMS)-FDE and a recursive-least-square (RLS)- FDE, is proposed for the cyclic-prefixed STBC single-carrier systems equipped with a diversity combining. In the WSB-FDE, the STBC-like matrix-wise block is first formulated from received blocks. The correction terms of the equalizer coefficients in each block are then updated so as to minimize a weighted squared- norm of the a posteriori error vector for the formulated block. Moreover, a square-root adaptive algorithm based on an unitary Givens rotations is proposed to achieve the numerical stability and computational efficiency in update procedure of the WSB- FDE. Finally, simulation results show in a typical urban (TU) channel that the bit-error-rate (BER) performance of the WSB- FDE is superior to that of the RLS-FDE as the STBC-like matrix- wise block length increases.