Minimal transmit redundancy FIR zero-forcing equalizer for space-time correlated noise ISI MIMO channel with space-time modulated code

摘要

A systematic method for designing FIR zero-forcing equalizer (ZFE) of space-time modulated coded (STMC) system based on non-maximally decimated filterbank is proposed. The physical channel considered is assumed to be MIMO with intersymbol interference (ISI) and span-time correlated noise. STMC is a space-time block code (STBC). Most of the STBC system required a Iong guard period to avoid inter-block interference but, with our designed equalizer, the guard period is not always necessary This can greatly enhance the spectral efficient of STMC especially when the channel dispersion is large. In our derivation, we first proposed some existence condition for the FIR ZFE of STMC. These include the maximal code rate STMC for given channel and the minimal required filter order. A verification method for the equalizability of given STMC precoder is also proposed. After that a parameterized solution of FIR ZFE of STMC is derived. Base on this parameterized result, the optimal FIR ZFE is obtained. By observing these results, we found that FIR ZFE can he further improved by adding a simple permutation in the system.