Various types of ad hoc wireless networks have been the subject of much recent interest. For our purposes, these networks can be characterized as a set of nodes that communicate with each other over wireless channels using little or no fixed infrastructure. In such a network, to reach its destination, a message may need to be forwarded over several intermediate links. Examples of this type network include mobile ad hoc networks (MANET's), sensor networks, and various hybrid ad hoc/cellular architectures. Such networks have the advantages of being rapidly deployable and requiring little or no fixed infrastructure. However, efficiently utilizing this type of network is a challenging task due, in part, to the interference between nodes, the time-varying nature of the communication channels, the energy limitations of untethered nodes, and the lack of centralized control via, for example, base stations.
This project is part of ongoing research with the goal of furthering understanding of basic performance trade-offs for ad hoc networks. This work takes a cross layer view and considers both physical layer limitations as well as higher layer performance metrics such as packet throughput. Techniques from queueing theory, optimization, and information theory will be utilized in this work. In contrast with our previous work on problems of this type in single-hop wireless settings, or, that is, models more appropriate for cases such as cellular networks, where all communication is to or from a single point, in this project, we are focusing on multi-hop ad hoc networks, with multiple transmitters and multiple receivers. In this environment, several new issues complicate the analysis. These include the routing and forwarding of traffic within the network and the scheduling of transmission and reception by each node. Specific problems that are being addressed include characterizing network stability and identifying adaptive resource allocation policies which maximize packet throughput.
