Research On Energy Optimized Routing Algorithms For Wireless Sensor Networks

Wireless sensor nodes are usually powered by limited batteries, and wireless sensor networks are generally deployed in unmanned outdoors or complex and dangerous regions. So, constrained energy is a prominent feature for wireless sensor networks. Optimizing the energy consumption of sensor nodes to extend the network lifetime is one key step to make wireless sensor networks into practical applications. Since the radio transceiver typically consumes more energy than any other hardware component onboard a sensor node, design of energy optimized routing algorithms is of great importance to prolong network lifetime.Based on analysis of energy consumption for data transmission, according to existing problems of energy optimized routing, and considering efficiency and balance of energy consumption of nodes, complexity of implementation, different network architectures and application requirements, this dissertation proposes planar and hierarchical energy optimized routing algorithms from the perspectives of energy cost, field theory of physics, fuzzy logic and non-uniform clustering. The proposed algorithms are also achieved and the performances are verified. The main work and contributions of this dissertation include:Firstly, considering the efficiency and balance of energy consumption of sensor nodes comprehensively, this dissertation has designed a new criterion of energy cost and proposed a distributed, energy optimized routing algorithm based on energy cost. In the algorithm, energy cost is computed according to the information of neighbor nodes, and the forward neighbor node with the minimum energy cost is selected as next hop, with lower computational complexity. Combined with the application of wireless sensor networks in coal mine, the energy cost based routing algorithm is proposed for long chain-type wireless sensor network in underground mine.Secondly, according to the many-to-one feature of data flow in wireless sensor networks, learning from the concept of field in physics, two multi-sink energy optimized routing algorithms are proposed based on virtual potential field and virtual electrostatic field. The virtual potential field is constructed based on the hop count of nodes to Sinks and the residual energy of nodes. The corresponding positive and negative charges are assigned to Sinks and data of sensor nodes depending on the residual energy of Sink's neighbors and sensor nodes. Based on this, the virtual electrostatic field is constructed. In the algorithm, the routing decision is made according to virtual force in the field and the method of mathematical physics is used to find the energy optimized routing.Thirdly, single-hop long-range forwarding scheme is proved to consume less energy within the one-hop communication range of the source sensor node or a current forwarder. The method is proposed to use social welfare function to predict the inequality of neighbors'residual energy. Parameters, such as the degree of closeness of node to the shortest path, degree of closeness of node to Sink and degree of energy balance, are put into fuzzy logic system. The fuzzy logic based routing algorithm is proposed to realize energy optimized, multi-factor, fuzzy routing decision.Lastly, an energy optimized clustering routing algorithm is proposed for wireless sensor networks. The corresponding energy optimized strategies are designed for three phases during the clustering routing, which includes cluster head election, inter-cluster routing and cluster formation. In the algorithm, cluster head is elected based on weights of node's residual energy, density and centrality. Energy optimized inter-cluster routing is constructed based on minimum hop count and residual energy of cluster heads. Cluster formation is made according to relay traffic of cluster head and distance between sensor node and cluster head.This dissertation mainly researches on the energy optimized routing algorithm for wireless sensor networks. Multiple energy optimized routing algorithms are proposed from different aspects, and effectiveness of algorithms is validated by simulations.