Robust Coding Methods for Space-time Wireless Communications

HONG, ZHIHONG. Robust Coding Methods For Space-Time Wireless Communications. (Under the direction of Dr. Brian L. Hughes.) Space-time coding can exploit the presence of multiple transmit and receive antennas to increase diversity, spectral e±ciency, and received power, to improve the 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 assumptions are often questionable in practice. In this dissertation, we present a new and general coding architecture for multi-antenna communications, which is designed to perform well under a wide variety of channel fading conditions and which (when di®erentially encoded) does not require accurate channel estimates at the receiver. The architecture combines serial concatenation of short, full-diversity spacetime block codes with bit-interleaved coded modulation. Under slow fading conditions, 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 known codes of the same complexity. When used with di®erential space-time modulation, these codes 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 could be further improved. Robust Coding Methods For Space-Time Wireless Communications by Zhihong Hong A dissertation submitted to the Graduate Faculty of North Carolina State University in partial ful ̄llment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering Raleigh 2002 Professor Brian L. Hughes , Chair Professor Hamid Krim Professor Don L. Ridgeway Professor J. Keith Townsend