For almost all the applications of wireless networks, the central optimization goal is to maximize network lifetime. Since each node in wireless networks is battery powered, energy conservation at each node is the primary concern that will greatly affect network lifetime. For the optimization goal of maximizing network lifetime in wireless networks, this project will integrate research and education to investigate some novel approaches for the coverage problems and the dominating set problems in wireless networks. Furthermore, the relationships between the solutions to the coverage problems and the solutions to the dominating set problems will be studied. The research work will focus on: designing new distributed and localized approximations for the coverage problems, developing new methods of constructing stable backbones in mobile or static wireless networks with the consideration of maintenance, integrating the proposed approaches for the coverage problems and the dominating set problems into coherent schemes so that new models can be derived to solve both the coverage problems and the dominating set problems. The research will be conducted from both theoretical and simulation aspects. The research component of this project will have a strong impact on both theoretical and practical aspects of optimization theory as well as wireless networks. It will accelerate the realization of the optimization goal in wireless networks. The education component of this project is a starting point to integrate research and education for the purpose of attracting both undergraduate and graduate students to the areas of optimization theory and wireless networks. The approaches proposed in this project and the findings as a result will be used as additional teaching materials to excite the students and to attract more potential students to conduct research in these areas.
This project is a theoretical and experimental interdisciplinary effort that aims to achieve the optimization goal of maximizing network lifetime for wireless networks. The primary investigated problems are the coverage problems and the Connected Dominating Set (CDS) problems in wireless networks. For the first set of problems, a series of algorithms and protocols were proposed for the complete coverage problem, the partial coverage problem, the k-coverage problem, and the target coverage problem. The effects of lowering down the control complexities and increasing the frequency of putting wireless nodes into active and sleep states alternatively to extend network lifetime were comprehensively investigated. The tradeoff between the two expenses was studied and general guidelines were derived for different application scenarios. The lack of fixed or pre-defined infrastructures in wireless networks motivates the investigation of the second set of problems. A CDS is a best candidate to serve as a virtual backbone for a wireless network. This project studies how to construct and maintain CDSs considering several constraints such as size, diameter, load-balance, fault tolerance, and routing flexibility. A series of CDS construction algorithms were designed and corresponding protocols for the employment of CDSs in wireless networks were proposed to facilitate routing, topology control, continuous data collection, data aggregation, event monitoring, indexing and data dissemination, area query processing, etc. This project has a strong impact on both theoretical and practical aspects of wireless networks. The project integrates research and education to attract both undergraduate and graduate students to the area of wireless networks. The proposed approaches and the findings in this project were used as additional teaching materials in related courses. Some specific research problems identified in this project were assigned to some graduate students as thesis topics.
