Mitra, Urbashi U of Southern California
With the emerging ubiquity of wireless communications, we continue to seek to provide high fidelity transmission of heterogenous data on demand. To fulfill this objective, significant improvements must be made over current wireless systems. The principal aim of the proposed research is to extend the state of the art of modulation and associated receiver designs for multiple-input/multiple-output wireless systems via the generalization of such channels. Spurred by the substantial capacity advantages promised by theoretical analysis for the use of multiple transmit and receive antenna systems, significant attention has been devoted to the design and analysis of spacetime coding and modulation schemes. Experimental transmit diversity systems have offered further hope that the gap between existing systems and theory can be bridged. The proposed research shall encompass commercial wireless systems such as cellular communication networks as well as more speculative systems such as ad hoc sensor networks. Abstractly, these two networks represent extremes in terms of network parameter information and control. A cellular communication system can be characterized as having a simple hierarchy with a basestation as central controller, modest power constraints, highly reliable users, and modest density of users per cell, and possessor of near-complete parameter information of all active users. In contrast, a sensor network will likely have a nested hierarchy of clusterheads communicating with a small set of nodes, severe power limitations, unreliable nodes, and dense deployments. We shall consider three main research foci: collaborative communication for sensor networks; transmit diversity schemes for interference channels; and the coupling of space-time methods with multimedia systems.
