Multiple antenna wireless communication systems: Capacity, coding and receiver design

This dissertation investigates information theoretic and signal processing aspects of multiple antenna systems.; When the channel state information (CSI) is available at both transmitter and receiver, the average capacity of a multiple antenna system in Rayleigh fading, subjected to an average transmit power constraint, is derived. It is shown that the optimal power adaptation rule in this case is the matrix generalization of the well-known water-filling algorithm. An integral equation, termed the cut-off equation, is also derived which determines the cut-off transmission value associated with this matrix water-filling algorithm.; When only the receiver has knowledge of CSI, the average capacity of a multiple antenna system is considered for Rician fading. When the transmitter has no knowledge of fading at all, the exact capacity is derived and evaluated for several special cases. When the transmitter has knowledge of the Rice factor, but not the exact CSI, lower and upper bounds are obtained for the capacity of multiple antenna systems in the presence of Rician fading.; It is proved that in the presence of quasi-static, independent Rayleigh fading, asymptotically as the noise power vanishes, the diversity gain of a space-time code in the multiple-access channel is exactly the same as what it would be in a single-user channel. A number of low-complexity signal processing techniques that improve the performance of space-time coded multi-user systems are also proposed.; Both uplink and downlink schemes, and also both space-time block and trellis coded systems are considered in these designs, paying special attention to CDMA-based multiuser systems. Several non-linear, turbo schemes that achieve performance competitive with that of a single-user channel even for high levels of multiple-access interference (MAI) are proposed for the uplink. The concept of space-time decoding along each resolvable path separately and then RAKE combining the space-time decoded outputs is introduced for multipath CDMA systems.; For the forward link, receivers that either completely ignore the MAI or blind adaptive receivers that learn about the MAI from the received signal itself are proposed. It is verified, via simulations, that the proposed signal processing schemes can provide significant performance gains compared to existing schemes.