After WLAN's phenomenal commercial success, multihop wireless networks, including wireless sensor networks, wireless mesh networks, and mobile ad-hoc networks, are expected to lead in the next wave of deployment. From a user's perspective, not only do these networks enable ubiquitous communication, but also they should provide means to support diverse application requirements, particularly, the ability to differentiate various types of data flows and ensure quality of service. The objective of this project is to design distributed algorithms and network protocols to solve several fundamental problems in multihop wireless networks, including end-to-end weighted bandwidth allocation, bandwidth assurance, and performance/overhead tradeoff in traffic differentiation. The study covers a variety of network conditions, including single-commodity or multi-commodity flows, single-path or multi-path routing, and static or highly-dynamic wireless networks. The research focuses on two hop-by-hop, routing-independent, light-weight approaches based on aggregate state and packet labels, respectively. Without maintaining any per-flow state, these approaches are able to implement traffic differentiation under aggregate or weighted maxmin models and have great flexibility in adaptation based on network/traffic conditions. The research results are expected to have significant intellectual and practical impact. Wireless sensor networks, mesh networks, and mobile ad-hoc networks will provide a pervasive communication infrastructure for modern societies and dramatically change the way people interact with cyberspace and physical environment. Traffic-differentiation capability allows these networks to meet diverse application requirements, which will promote their entrance into the marketplace. As an educational effort, this project actively involves senior undergrads and minority students.
After WLAN's phenomenal commercial success, multihop wireless networks, including wireless sensor networks, wireless mesh networks, and mobile ad-hoc networks, are expected to lead in the next wave of deployment. From a user's perspective, not only do these networks enable ubiquitous communication, but also they should provide means to support diverse application requirements, particularly, the ability to differentiate various types of data flows and ensure quality of service. This project makes contributions in designing distributed algorithms and network protocols to solve several fundamental problems in multihop wireless networks, including end-to-end weighted bandwidth allocation, bandwidth assurance, and performance/overhead tradeoff in resource management. Traffic differentiation in multihop wireless networks is drastically different from its counterpart in wired networks. Our work in the past five years has expanded the theoretical and engineering knowledge about how to achieve wireless traffic differentiation effectively and efficiently. The intellectual outcome is summarized as follows: First, we make a few key findings on the deficiency of current wireless technologies (such as 802.11 DCF) in their bandwidth distribution among competing flows. Second, we introduce several fundamental technologies for weighted bandwidth allocations in multihop wireless networks, including proportional increase synchronized multiplicative decrease, queue spreading, packet labeling, four localized maxmin conditions, dynamic weight adaption and proportional packet scheduling, to name a few. Third, we design an array of fully distributed protocols to implement the aforementioned technologies in realistic wireless settings; many of them are designed for the popular 802.11 networks. Fourth, we perform comprehensive evaluation on our solutions, mostly by simulations on ns2 and sometimes backing simulations with experiments on a small testbed. Wireless sensor networks, mesh networks, and mobile ad-hoc networks will provide a pervasive communication infrastructure for modern societies and dramatically change the way people interact with cyberspace and physical environment. The research under this project advances the state-of-the-art wireless technologies in complex application scenarios. The educational outcome includes curriculum enhancement and student training. New course materials have been developed on routing, packet scheduling and bandwidth management in wireless networks, and they are incorporated into the networking courses. Two Ph.D. students who worked on this project have graduated. Four undergraduate students participated in the research. They worked on weekly reading/experimental assignments, and one of them joined the graduate program. As an outreach activity, research results from this project were presented to field engineers in the city’s transportation department.
