The Research Of Routing Protocol In Wireless Sensor Network

Wireless sensor network(WSN),which is the integration of micro-sensors, embedded computing, modern networks and wireless communication technologies, is a novel computing model and promote the development of science and technology and social progress. Through the real-time collaboration of the integrated micro-sensors, it can be used for sensing and processing information, and then can provide a large amount of reliable information. it has broad application prospects not only in military applications, environmental monitoring but also in disaster rescue , space exploration and so on.Routing protocol is a mechanism which transmits the data from the source nodes to the destination nodes. In wireless sensor network, the energy of the node is very limited and not easy to recharge, so the foremost goal of the routing protocol design is to reduce the energy consumption and extend the lifetime.According to the comparison and analysis of various types of typical routing protocols, this thesis focused on LEACH (low energy adaptive clustering hierarchy) protocol. Since the LEACH protocol has some shortcomings when the cluster heads communicate with the base station directly, this thesis proposed an improved LEACH protocol based on a spanning tree—LEACH-T protocol. In the LEACH-T protocol, it generated a tree constituted by the cluster-heads and makes the base station as the root of the tree. Every node in the network selects a parent which has the lowest depth from its neighbor cluster-heads, and then forwards the packets to its parent. If a node is not within the communication zone of any cluster-heads, it can be allowed to select another leaf node as its parent. The cluster-heads not only receive the data from the leaf nodes, but also receive packets transmitted by the cluster-heads which have higher depth in the tree. After that, the cluster-heads perform local data fusion to reduce energy dissipation, and then send those packets along the tree path till the base station.Simulate the performance of the LEACH-T protocol based on the TinyOS platform and the results show that, compared to the original LEACH, LEACH-T is more energy efficient and can prolong the network lifetime.Finally, we prolong the network lifetime in the terms of balancing the load, and propose the multi-path based GEAR protocol—MGEAR protocol. MGEAR established multi-path from the source node to the destination node. The simulation under TinyOS platform shows that, compared to GEAR, MGEAR protocol can extend network lifetime.