Research And Improvement On Clustering Routing Algorithms For Wireless Sensor Network

With the rapid development of wireless communication, sensor and network, the size of wireless sensor becomes very small, the capability for computation becomes very strong, but the cost becomes very low. The changes make the large-scale deployment of wireless sensors possible. A network made of many sensors can do something that traditional networks can’t do by cooperation with each other. WSNs are usually deployed in the severe environment such as wild. A huge number of nodes are sown randomly. It’s almost impossible to maintain the nodes by man. All the nodes look after themselves after deployment. Once the power is run out, the node dies. How to make the most use of the limited amount of energy of sensor node is the starting point of all research about WSN including routing algorithm design. This paper is aimed at researching and improving clustering routing algorithm for WSN based on LEACH.Firstly, the characteristic, architecture, node structure, protocol stack, etc of WSN is outlined. Then, several classical clustering routing algorithms such as LEACH, PEGASIS, TEEN, LEACH-C are analyzed in detail. Against the disadvantages of existing routing algorithms, an improved one, LEACH-PSOT, based on LEACH is proposed and simulated at last.LEACH takes a distributed and random way to cluster all the nodes and can’t make sure the number of cluster heads is optimal. Without considering the location of nodes, the nodes can’t be clustered evenly, so some nodes have to communicate with remote cluster heads and consume more energy. LEACH-PSOT uses particle swarm optimization (PSO) algorithm to cluster centrally on the sink node. It takes into consideration not only the remained energy of nodes but also the distance between node and cluster head; When LEACH is in the steady stage, all data is sent to cluster heads and then sent to sink. The distance between cluster head and sink is usually far. According to the first order radio model, the energy consumed for sending is in direct proportion to the fourth power of distance between source and destination when the distance is far enough. In such circumstances, the multi-hop route is better than the single-hop route. LEACH-PSOT organizes all cluster heads as a spanning tree. Only the root node of the spanning tree can communicate with sink directly. Other cluster head can only send data to its parent node and finally to sink through the root node. This kind of tree-based multi-hop communication can reduce the number of nodes which communicate with sink directly and lower the energy consumed by far-distance communication. When the data is relayed, it can be aggregated to lower energy consumption further. Simulation shows that LEACH-PSOT can reduce and balance energy consumption effectively and extend the lifetime of WSN.