Research And Design Of Energy Efficient Routing Algorithm In Wireless Sensor Networks Based On Zigbee Protocol

Sensor nodes'energy is the most important resource for wireless senor networks, which decides the lifetime of the network directly. So the first principle in designing routing protocol in wireless sensor networks is saving energy, so as to effectively prolong the network lifetime. The paper sets forth the basic theories about wireless sensor networks and its routing protocol, discusses in detail the hierarchical routing protocols which perform better in energy saving. The paper takes the classical hierarchical routing protocol LEACH as the object for further research and the basis for further improvement. And an improved algorithm named LEACH-improved is proposed according to the problems exist in LEACH. The main works of this paper are as follows:1. To deal with the problems exist in the cluster head election scheme of LEACH, in LEACH-improved, temporary cluster head and final cluster head these two concepts are introduced in the first round cluster head election. In the first round, the final cluster head is decided depending on the results of the competition between temporary cluster heads that are in the same cluster radius according to their energy. This scheme can make a uniform distribution of cluster heads, avoid the elected cluster heads from being too centralized. In LEACH-improved, besides the first round execution, the cluster heads in other rounds are selected by the cluster heads in the last round according to their cluster members'residual energy. And this mechanism can prevent the nodes with low energy from becoming cluster heads.2. On account of the problems exist in the cluster reconstruction mechanism of LEACH, LEACH-improved adopts the local cluster reconstruction strategy. In this algorithm, in every round, each cluster elects its new cluster head and reconstructs the cluster independently. This method can eliminate the energy consumption caused by large-scale cluster reconstructions.3. To solve the problem in the data communication mechanism of LEACH, in the algorithm LEACH-improved, a hierarchical tree structure network with sink as the root is formed by all the final cluster heads to realize multihops routing between final cluster heads and the sink. As a result, energy costs brought about by long-distance data communications in cluster heads have been eliminated.4. Based on TinyOS platform, LEACH-improved is designed and realized with the language nesC. The performance of the two algorithms LEACH-improved and LEACH are compared by using the TOSSIM simulator. The results show that LEACH-improved performs better than LEACH in saving nodes'energy, balancing network load, and prolonging the network lifetime. LEACH-improved algorithm is also tested in the paper by using Micaz nodes and other experiment equipments, and the result indicates that this algorithm has realized multihops routing between sensor nodes and the sink node. In a word, the correctness and validity of the proposed algorithm has been validated.