Energy Efficient Protocol For Wireless Sensor Networks

Wireless sensor network, which is made by the convergence of sensor, nested computation, networks and wireless communication technologies, is a novel technology about acquiring and processing information. It can be used for sensing, collecting and processing information of monitored objects. Wireless sensor network has promising application future, and it is also one of the most important technologies in 21^st.In this paper, the issues of the routing protocols of wireless sensor network are discussed. The numbers of sensor nodes in wireless sensor networks are numerous and single node is extraordinarily limited in resource. Therefore, energy efficiency is a dominant consideration in deciding the routing technique of sensor networks. The characters and protocols of wireless sensor networks are researched. A new hierarchical routing protocol is proposed, which is energy efficient in data gathering (EEDGP). It improves the disadvantages of network lifetime and network expansibility in LEACH.In EEDGP, sink node takes the responsibility of discovering global optimal routing. It partitions the network into several clusters based on the density of nodes, remain energy of node, average remain energy of network and distances between the nodes. Each cluster contains a cluster-head and some common nodes, and cluster-head is responsible for transmitting sensed data to sink node. Sink node uses Prim algorithm to build a minimum tree which is composed of the sink node and the cluster-heads, and the root of the routing-tree is the sink node. While one of the cluster-heads wants to send data to the sink node, it transmits the data to its upper nodes in the tree. Intuitively, cluster-head uses multi-hop to transmit the sensed data to the sink node. In one cluster, the protocol adopts the same algorithm to build a minimum tree whose root is the cluster head. Based on the quantity of nodes in one cluster, the sink node creates TDMA schedule for each cluster. Each a few turns, the sink node re-chooses cluster-heads and partitions the network. So the protocol performs well by distribute energy dissipation evenly throughout the sensors.At last, the protocol is simulated on Network Simulator (NS2). Simulations show that EEDGP prolongs the network lifetime as much as 2.5 times than LEACH, and it can achieve better network expansibility.