Research Of Energy-Efficient Routing Technologies In Wireless Sensor Network

Wireless sensor network is an extremely important research field in computer networks at present, and has an extensive application prospect. However, as wireless sensor nodes are characterized by limited energy availability, energy efficiency is a key issue in designing the network. Efficiently using nodes’ limited energy and extending network lifetime as possible is the basic content of application research on wireless sensor networks. For the basic research content, several key technologies about energy-efficient routing are studied.1. For the optimal deployment of heterogeneous nodes and routing of monitoring data in heterogeneous sensor networks, a clustering heterogeneous network routing algorithm based on the mixed integer programming (CHNMIP) is proposed. Firstly, in order to minimize the sum of equivalent path distance from common nodes to sink, convert the optimal deployment of heterogeneous nodes into a mixed integer programming problem. Solve the problem using the decomposition algorithm, which can ensure the heterogeneous nodes are optimally deployed as possible and the solution process has the polynomial complexity. And then all common nodes are dynamically clustered, and the monitoring data is transferred to corresponding cluster heads or heterogeneous nodes along the optimal path. CHNMIP overcomes the defects of the traditional routing algorithms for heterogeneous networks, such as not ideal deployment of heterogeneous nodes, and single transmission path. In addition, CHNMIP reduces and balances energy consumption of network, and prolongs the network lifetime.2. For the wireless sensor network with unignorable aggregation overhead, a compressing minimal energy-consumption adaptive aggregation routing algorithm(CMEAAT) is proposed. Firstly, a propagation tree is constructed whose performance is between SPT and MST, so as to adapt to different types of networks. And then the aggregation benefits of nodes are defined according to aggregation overhead and transmission overhead. Data are aggregated only at the nodes where the aggregation benefits are greater than zero, so as to avoid unnecessary aggregation overhead. It solves the problem of excessive aggregation in the existing aggregation routing algorithms. In addition, the adaptively aggregated data is further compressed using the embedded zero-tree coding algorithm based on the second generation wavelets(EZC-SGW) to reduce transmission overhead. The simulation results show CMEAAT can effectively reduce energy overhead and prolong the network lifetime, compared with the traditional aggregation routing algorithms.3. As the dynamic programming algorithm has high computation efficiency, and is very suitable for multi-hop transmission of wireless sensor networks, the lowest energy consumption routing algorithm(LECR), the energy balancing and lowest energy-consumption routing algorithm(EB-LECR), and the least delay and low energy-consumption routing algorithm (LD-LECR) are respectively proposed on the basis of the dynamic programming idea. Firstly, a real network is converted into a standard dynamic programming model where all nodes are clearly divided into several discrete stages through adding virtual nodes. And then solve the optimal transmission path step by step using the dynamic programming algorithm according to the design goal of network. It overcomes the defects of traditional routing algorithms such as the higher computation complexity. The simulation results indicate the proposed routing algorithms are superior to the traditional algorithms in the aspects of energy overhead, energy balancing and time delay, etc.This paper is supported by the National Natural Science Foundation of China (No.60672137,90304018,61171075), the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20060497015), the State Key Laboratory of Software Development Environment (No.SKLSDE-2009KF-2-02), and the New Century Educational Talents Plan (No.NCET-08-0806),.