The Research Of Energy-Efficient Protocol For Large Wireless Sensor Networks

Wireless senor network(WSN) is a late-model wireless network with non-infrastructure and self-organization. With the development of micro-electronic, sensor technology and communication technology, WSN developed very rapidly and has made a great progress in recent years. It has been successfully used in some military and civilian applications. WSN has a bright future for its extensive use. But for the characteristics of WSN such as hardware resource limitation, power capacity limitation, data-central, self-organization, multi-hop routing, dynamic topology, dense distribution with numerous nodes etc, many active routing protocols used in other networks are not suitable for WSN, especially for large WSN. Under this circumstance, this paper focuses on the research of protocols for large WSN. Firstly, we describe the architecture and correlative concepts of WSN, and then analyze the characteristics, performance evaluation criterions and effective factors in designing the routing protocols of WSN. We pay attention to the study of some proposed classical protocols and a comprehensive evaluation of them. We find the directed diffusion algorithm with data-central and good expansibility is propitious to large WSN, but the directed diffusion routing creation mainly depends on the plain flooding, which will consume much energy resource and especially more serious in large WSN. To resolve this problem, we propose a new improvable routing protocol—Directed Diffusion Based on Clustering routing protocol (DDBC).DDBC is an energy-efficient routing protocol that can reduce network topology by clustering and save energy by suppressing the redundant message in plain flooding. We adopt the passive clustering strategy after the study of clustering mechanisms and algorithms. Passive clustering means it is necessary to create network topology only when there are data-requests in network, and the creation and maintenance are both local-happen and need no extra control commands, this results in energy saving. In clustering strategy, the selection of cluster heads and gateway node are most important. In this paper, we select the cluster head by using a mechanism named "first declaration wins"; the gateway node is selected according to the rule that makes trade-offs between the network robust and the energy-efficiency. We present DDBC and its implementation algorithm in detail in this paper. We also simulate the routing protocol in NS2, the results show that DDBC is more energy-efficient and has a good performance even when the number of nodes increased in large scale.