Low-Complexity Incremental Transmission for Multiple-Antenna Wireless Systems

In designing next-generation wireless systems, there is desire to increase the transmission rate by increasing the number of antennas while at the same time managing the complexity of the system. In this thesis, we develop and analyze low-complexity schemes that we call incremental multiple-input multiple-output (IMIMO) for exploiting multiple antennas for reliable high rate communications. Unlike multiple-input multiple-output (MIMO) communications without feedback, the schemes we propose do not require a space-time encoder or decoder because they only use one transmit antenna at a time and they exploit automatic repeat request (ARQ) feedback. We develop an outage analysis that demonstrates IMIMO can outperform MIMO without feedback in some wide regimes. Using partial channel state information obtained at the transmitter (CSIT) from the ARQ feedback, we propose simple power control policies to further improve the performance of IMIMO. We also explore receive antennae selection to further simplify the system. Finally, we analyze these systems in the limit of large number of transmit and receive antennas, and large number of transmissions which gives some useful insights for designing IMIMO systems.