Research On Power Adjustment Based Topology Control Technology In Wireless Sensor Networks

As a combination of computing, communication and sensor technologies, wireless sensornetworks (WSNs) have been a hot research spot in the field of computer science because itsunique features and broad application prospects. Wireless sensor networks are typicallylarge-scale, self-organized, random deployed, with limited resource and frequently changedtopologies, and thus topology control plays an important role in wireless sensor networks. InWSNs, topology control not only ensures the coverage and connectivity of the network but alsoimproves the energy efficiency, prolongs the network lifetime, reduces the conflict andinterference of signals, increases the network capacity, reduces the complexity of routingcomputation and enhances the reliability and scalability of the network.In this paper, power adjustment based topology control technology is studied deeply. Theresearch includes proximity graph based power control algorithms, fault tolerance of the targettopology, adaptivity to the network environment and application scenario, the energy holeproblem in WSNs and parallel transmission strategies used for power control. The main contentsand innovations include the following aspects:(1) On the basis of the analysis on proximity graph based topology control algorithms, aβ-Skeleton based power control algorithm named β-STC is proposed. Simulation results showthat β-STC improves the energy efficiency and reduces the network delay compared with RNGand GG model.(2) The fault tolerance of topology control algorithms are studied, and a k-fault tolerancepower control algorithm named HFTPC is proposed. The sensor nodes in the network are dividedinto clusters. The nodes in clusters construct the topology using the RNG model; the backbonenetwork composed of cluster heads maintains k-connectivity by k-CCHA algorithm. Simulationresults show that HFTPC algorithm mitigates the competition of wireless channel, reducescommunication interference and gets better real time performance.(3) On the basis of the analysis on the influence of path loss exponent and energy controlcoefficient on the minimum covering district, a distributed and adaptive power assignmentstrategy named LA-TPA is proposed. It contains a topology construction phase and a topologymaintenance phase. Simulation results show that both path loss exponent and energy control coefficient have a significant influence on target topologies. The target topologies meeting therequirements of various applications can be obtained by adopting different energy controlcoefficient. In addition, when the path loss exponent and energy control coefficient are3and1.6,the target topology constructed by LA-TPA is better than XTC and STC.(4) A novel power based energy hole analysis model is proposed. And the main presentmitigation strategies of energy hole problem are analyzed using this model. On this basis, animmune clone selection algorithm based power control strategy is proposed to mitigate the energyhole problem in wireless sensor networks. Simulation results show that the proposed algorithmmitigates the energy hole problem, improves the energy efficiency, prolongs the lifetime of thenetwork.(5) Aiming at the exposed node and the hidden node problem caused by power controlstrategies, a parallel transmission MAC protocol named MAC4PC is proposed to increase thespace utilization and improve network throughput. Simulation results show that, the performancemetrics of MAC4PC is much better that present parallel transmission MAC protocols.