The Research Of Topology Control Based On Energy Balance For Wireless Sensor Networks

Wireless Sensor Networks (WSN) as a new network technology developing rapidly and attracting popular significance, integrates technologies from different disciplines like sensors, computer science, communication and micro-electronics, and is clearly characterized by interdisciplinary. Thus WSN has indicated an extensive application prospect in the fields of national defense, environmental monitoring, precision agriculture and healthcare. Nevertheless, some weak points with WSN could be seen in the same time as it does not need fixed facilities, and its systems and junctions could only carry limited power, and communication might be easily interfered as WSN is based on data. Therefore, how to guarantee the connectivity of networks, how to improve energy consumption efficiency of networks and how to prolong the lifecycle of networks are the problems demanding urgent solutions. Topology control for WSN is not only the basis for the running and application for other protocols, but a crucial technology as well to guarantee networks connectivity and to raise energy consumption efficiency of networks and prolong the lifecycle of networks.In view of the influences by the balance of node energy consumption on the lifecycle of networks and the method of dynamic topology optimization and graph theories, this thesis, mainly based on the technologies and theories concerning topology control for WSN, aims from a new angle at the research of topology construction and topology maintenance of topology control. And relevant arithmetic is also put forward for topology construction of isomorphic and isomerous WSN and static and dynamic topology maintenance of WSN. Some new methods and thinking for research could be witnessed in this thesis and it mainly consists of the following aspects:①Not only is the lifecycle of WSN connected with each networks node, but with balance of node energy consumption in the whole WSN. In the thesis, the author, considering the need of efficiently balancing networks node energy by means of networks topology control, creates a topology control arithmetic EBDTCA based on balanced distribution of energy. And two factors of communication energy loss between nodes and surplus energy are introduced to building cost models of the communication link road. The said arithmetic, which does not need accurate graphic information about nodes, could finish in a mode of distribution partial topology optimization of nodes, and adjust powers between nodes through regional network topology information and thus result in the optimization of the whole WSN. EBDTCA is a lightweight, distribution-based and topology-controlled arithmetic. It is shown by emulation experiments that such EBDTCA, compared with classic topology-controlled arithmetic, can more efficiently prolong the lifecycle of WSN.②On the basis of EBDTCA, the author extends the thinking of dynamic topology optimization to isomerous WSN. Given the fact that one-way communication link roads exist in isomerous WSN, the author betters EBDTCA and further puts forward the new arithmetic EADTC. Such EADTC could adapt itself to the isomerous WSN caused by the difference between the initial energy and communication capability of nodes, could guarantee the network connectivity and build network topology structure with the minimum cost and could finally optimize network topology in terms of the surplus energy of nodes. Emulation experiments show that such arithmetic could dramatically prolong the lifecycle of networks.③Triggering conditions for topology maintenance are deeply analyzed and indices to which attention should be attached during designing the topology maintenance mechanism are put forward. Given the need of building the preparatory plan for static topology maintenance and the principal of existence and the principal of exclusion, the author brings forward the calculation way to construct the minimum spanning tree sets. On the basis of constructing minimum spanning tree sets for each nodes distributed, the author furthermore raises the calculation way to build preparatory topology plans for networks, and thus realize the time static slice-based topology maintenance strategies. The static topology maintenance could satisfactorily adapt the requirement of real-timing by WSN. The result of emulation experiment of static topology maintenance strategies demonstrates it is basically possible that energy on each node is consumed in balance. In the mean time shortening of network lifecycle in emulation experiment and variance of node surplus energy going too far are analyzed as well in the thesis.④On account of the difference of static and dynamic topology maintenance technologies, the existing model for predetermining node energy consumption rate has its own problem that there would be great difference between its actual application and assumption. The way of predetermining calculation for node energy consumption, integrated with MAC Layer Protocol, is created. Based on the new calculation way, a parameter,βV ar(u)describing the imbalance between network node energy, called deviation degree of surplus node energy is also pulled in to build the calculation way for dynamic topology maintenance. In line with various application requirements by WSN, frequency in operating dynamic topology maintenance could be regulated and controlled by adjustingβV arLimit. Such dynamic topology-controlled arithmetic has a quite strong adaptation. In addition, this arithmetic, by way of regulating the triggering frequency of topology network maintenance throughβV arLimit, could well fit poor networks in which data packets are easily missed. Robustness of this way of calculation is clear. Emulation result indicates that the topology control integrating dynamic topology maintenance and EBDTCA could more efficiently balance energy consumption on nodes and further prolong the lifecycle of networks.In the thesis topology control is divided into topology construction and topology maintenance. The energy-based calculation way for topology construction and static and dynamic topology maintenance technologies for isomorphic and isomerous WSN are researched, which are analyzed from the angle of theories as well. The emulation result also proves the validity of such way of calculation.