Research On Topology Control Of Wireless Sensor Networks

In recent years, technological advances in wireless communication, micro electromechanical system(MEMS)and micro sensor have enabled the development of low-cost,low-power, multifunctional tiny sensor nodes to communicate unrestricted in short distances.These tiny sensor nodes, which consist of sensing, data processing, geographical location andcommunicating components. These sensors have the ability to communicate either amongeach other or directly to an external base-station(BS). A Wireless Sensor Network(WSN)contains hundreds or thousands of these tiny sensor nodes for monitoring of specifiedparameters in the target area, in a WSN, sensor nodes self-organized build a network andtransmit the sensing information to the sink node in single-hop or multi-top manner.The application of wireless sensor networks involved in military, medical, environment,industrial and other fields, it has features such as flexible networking, self-organizing,adaptability to environment etc. these features makes the application prospect of wirelesssensor networks is widely optimistic. However, WSN have several restrictions, such aslimited energy, limited computing capacity and limited bandwidth resources. Currently,extensive research has focused on design energy efficient algorithms and protocols to saveenergy and to prolong the network lifetime. Among them, the topology control to improve thenetwork energy efficiency, reduce the node communication interference, prolong the networklifetime plays a very important role.The goal of topology control is to dynamically change the network topology througheither changing the nodes transmitter power, introducing hierarchies in the network or bysimply turning some nodes off for a certain amount of time，and maintain some importantproperty of the network, e.g. connectivity and coverage, at the same time, reduce the energyconsumption of the nodes, to prolong the life of wireless sensor network. At present, researchon topology control is divided into two parts: power control and hierarchical clusteringalgorithm. Low Energy Adaptive Clustering Hierarchy(LEACH) is the most classic to thebased on clustering hierarchical routing algorithm, aims to balance each sensor node energyconsumption and prolong the network lifetime in wireless sensor network.This dissertation discussed the working principle of LEACH algorithm，it has theproblem that the nodes with less residual energy become the cluster heads, which distributionare uneven and nodes energy consumption within a cluster is not uniform in LEACH.Because of these problems, resulting in accelerated death of the nodes and the energyefficiency decreases. Based on this， we propose an improved LEACH algorithm to solve thisproblem, called LEACH-B algorithm. This method take into consideration the residual energy of the nodes, the cluster head distribution and distance from the BS. And then the improvedalgorithm is simulated using MATLAB software, and the simulation results are analyzed.Through the result of the simulation of the LEACH-B algorithm, this method is improvedenergy efficiency, balance the network energy consumption more effective, thus effectivelyprolong the lifetime of the network.