The Study Of Wireless Sensor Network Low-power Routing Protocol Based On Particle Swarm Optimization

With the great progress in micro-electromechanical systems, embedded technology, sensor technology and wireless communication technology, wireless sensor network (WSN) has been well developed. Currently, WSN has become the research focus in the IT field, and has been widely used in many fields. However, the energy, storage, computing and communication capabilities of sensor nodes are so limited. Thus how to gather information and transmit it to the base station in an energy-efficient way becomes the primary objective of WSN routing designing. At present, most wireless sensor network is using clustering routing protocol to reduce energy consumption of the network. But they only pay attention to reducing energy consumption of a single node. Because of this, the low-power routing protocol of wireless sensor network based on particle swarm optimization (PSO-LP) is investigated, which improves the classic clustering routing protocols-LEACH. Compared with the LEACH protocol, the PSO-LP protocol not only pays attention to reducing the energy consumption of a single node but also to energy-balanced in the entire network.Firstly, improve the fitness function of particle swarm optimization (PSO) particle. The fitness function decides the overall performance of selected cluster head, which mainly considering the remaining energy of the elected cluster head node, the average distance between the node of the cluster members and elected cluster head, the equilibrium extent of cluster member nodes’remaining energy and the base station location. Considering of the remaining energy makes the node having sufficient energy to be the cluster head node. The average distance between the cluster members and elected cluster head is more nearer, the energy consumption in transmission between them is more less. Considering the equilibrium degree of the residual energy avoids the algorithm into a local optimum, which makes the particles having a greater ability to search the optimal solution region and the energy consumption of the entire network having been balanced. Base station position influences the energy consumption of cluster head node.Secondly, in order to avoid the failure of a single cluster head overloading, the PSO-LP protocol combined the single cluster head with double cluster head, and elected two cluster heads as the master and vice cluster head respectively. The master cluster head is responsible for receiving and integrating the data of the member nodes and sends them. The vice cluster head is responsible for sending the received information from the cluster head to the base station. Then, two cluster heads of the same cluster maintain information with each other, when any cluster head of the two cluster heads failures due to abnormal reasons (this case in practical applications is likely to occur) or the energy bellowing to the limit threshold. Another cluster head assumes the function of the two clusters within a cluster at the same time.When the energy of the two cluster heads is all less then the limit threshold, re-elect the cluster heads. So it can avoid the empty phenomenon of network or the information confusing because of one cluster head’sudden failure, and each cluster don’t wait for re-election of cluster periodically, which makes the data transmission phase lasting longer and ensure that the entire network having a higher throughput and longer life cycle at lower power levels.Finally, it uses single and multi-channel hybrid routing strategy in the data transmission phase:the nodes of the cluster members take a single hop to communicate with the cluster head directly; the inter-cluster routing takes a combination of single-hop and multi-hop, the master and vice cluster head cooperated, the main cluster head fusions the cluster members’information and sends to the base station with a single hop or multi-hop way, the vice cluster head communicate with the base station directly. The transmission achieves multi-path to the sink node, so it can save the nodes’energy and extend the network life cycle, ensure the robustness of the routing.The MATLAB simulation results prove that the life cycle of PSO-LP protocol is increased greatly compared with classical LEACH and LEACH-PSO protocol; and after the same cycle, the remaining energy of PSO-LP is higher than LEACH and LEACH-PSO, which shows the efficiency of the PSO-LP in balancing energy consumption of the network.