Robust Coding Methods For Space-Time Wireless Communications

Abstract

Space-time coding can exploit the presence of multiple transmit and receive antennasto increase diversity, spectral efficiency, and received power, to improvethe performance in wireless communication systems. Thus far, most work on space-time coding has assumed highly idealized channel fading conditions (e.g., quasi-static or ideal fast fading)as well as perfect channel state information at the receiver. Both of these assumptionsare often questionable in practice. In this dissertation, we present a new and general coding architecture for multi-antennacommunications, which is designed to perform well under a wide variety of channel fading conditionsand which (when differentially encoded) does not require accurate channel estimatesat the receiver. The architecture combines serial concatenation of short, full-diversityspace-time block codes with bit-interleaved coded modulation. Under slow fadingconditions, we show that codes constructed in this way achieve full diversity and perform close to the best known space-time trellis codes of comparable complexity. Under fast fading conditions, we show that these same codes can achieve higher diversity than all previously knowncodes of the same complexity. When used with differential space-time modulation, thesecodes can be reliably detected with or without channel estimates at the transmitter or receiver. Moreover, when iterative decoding is applied, the performance of these codes couldbe further improved.