Research On Theories And Technologies Of Coverage And Topology Control For Wireless Sensor Networks

Recent advances in micro-electro-mechanical systems (MEMS) technology, wireless communications, and digital electronics have enabled the development of the wireless sensor networks (WSNs), which connectes the real world and information world, and deeply change the interaction between people and nature. How to choose coverage and topology control schemes for different applications are the fundamental issues in wireless sensor networks. The coverage and topology control schemes direct affect the energy-efficiency, communication-bandwidth and process-ability which are all limited in WSNs. They also determine the improvement of the QoS of apperception, surveillance, sense and communication in WSNs.In this dissertation, the key problems about coverage deployment and topology control method are studied, and four main issues are covered: First, some recent novel theories and algorithms for wireless sensor networks coverage and topology control problems are reviewed, and the taxonomy is described. And then, we analyze optimal coverage for routing in three-dimensional wireless sensor networks, propose a novel model for dynamic wireless sensor network infrastructures, and consider the topology control problem in mobile wireless sensor networks respectively. Meanwhile, relevant protocols and algorithms are presented. Moreover, the simulation results of each protocol and algorithm are analyzed. The work of this dissertation is supported by the National Natural Science Foundation of China (No. 60572037) and the Innovation Foundation of Science and Technology for Excellent Doctorial Candidates of Beijing Jiaotong University under Grant No.48013. The main innovations in the thesis are outlined as following:(1) For optimal coverage for routing in three-dimensional wireless sensor networks which is a NP-hard combinatorial optimization problem, we proposed a new solution used techniques from Computational Geometry, Graph Coloring and established a new model for optimal coverage. We also proposed an energy-efficient distributed heuristic algorithm to find the optimal coverage routing path. Based on the model and algorithm, we presented a three-dimensional optimal coverage routing protocol in a distributed manner. To evaluate the performance of the algorithm, a time complexity analysis was given for each operation. In the end, we analyzed the coverage quality and compared the network lifetime with several typical protocols. Simulation results show that proposed routing protocol has low time complexity and it is considerably effective, scalable and robust.(2) We proposed a novel model for dynamic wireless sensor network infrastructures. Based on this model, we obtained the average connectivity results used methods from the mean-field and continuum theory. To evaluate the performance of the analytical model, we also gave the comparison results of the degree distribution, average path length, clustering coefficient and network congestion which are typical topology property parameters. Simulation results show that proposed analytical model is considerably effective, practicable and precise.(3) We present a fully distributed routing protocol, Cooperative Energy-efficient Topology Control (Co-ETC), whose goal is to achieve energy efficiency in mobile wireless sensor networks. Based on underlying routing graph, the proposed scheme allows each node (with or without mobility) to locally select communication neighbors and dynamically adjust its transmission radius accordingly, such that all nodes together self-form an energy-efficient topology. The simulation results indicated that the proposed scheme was feasible. Compared with existing state-of-the-art algorithms and protocols, Co-ETC has better energy-efficiency. Moreover, it can adapt to mobile environment well. The patent for invention of the Co-ETC routing protocol has been requested (Accept No.: 200710121122.6).