Research On Energy-Efficient Routing Algorithm And Distributed Scheduling Approaches In WSNs

The advances in wireless communication technology, microelectronic technology and sensor technology have promoted the development of wireless sensor networks(WSNs) technology. The WSNs have been paid more attention in both academic and industrial fields, and used in a variety of military and civil applications. As a result, WSNs have become the frontiers of research in measurement and control.One of the most important goals in WSNs research is to decrease energy consumption and maximize network life to meet application requirements. So, routing protocol and distributed scheduling approaches in WSNs are considered in this research. It can be described in four parts.1. To solve the problems of limited energy and unbalanced energy consumption with clustering routing algorithms, this thesis proposes an Energy-Efficient Link Clustering (EELC) routing algorithm based on local competition by multi-weights. Though, EELC doesn't need the whole network information, it can build the link structure from low residual energy node to high residual energynode. Theoretical analysis and simulation results prove that the proposed algorithm can effectively keep a good balance of energy consumption and achieve the better topology control. Moreover, it significantly improves the lifetime of networks.2. To solve the problems of the link instability and asymmetry in WSNs, the multiple time scales link estimation (MTSLE) algorithm is proposed. Long and short time scales link estimations are taken into account. Then, to build the topology structure by both stable link and bursty link, a bursty links discovery strategy is designed to achieve opportunistic routing. Meanwhile, the algorithm also considers a multi-path ACK policy for packet duplication caused by the asymmetry bursty links to reduce the number of duplicate packets. Experimental results show that MTSLE not only reduces the average path length but also saves energy and improves the packet reception rate to some extent. Furethermore, the multi-path strategy also solves the problem of packet duplication.3. In receiver-initiated asynchronous sensor network MAC protocol, the sender wastes a lot of time on idle listening while establishing communication. A new asynchronous MAC protocol for low duty-cycled is presented, named Two-way Rendezvous MAC (TR-MAC) algorithm. TR-MAC adopts dynamic beacon packet interval mechanism to establish two-way time rendezvous and time estimation scheme based on time margin. TR-MAC is implemented under the UPMA frameworkin TinyOS. Experiments have been achieved to evaluate the performance of the proposed protocol. The results show that TR-MAC can further reduce the duty cycles of nodes and network latency, and improve network performance thereby.4. Up to now, the evaluation method for low power protocol based on simulation are lack of accuracy. And, at the same time, the over methods based on experiments are difficult to achieve large-scale evaluation. So, an evaluation framework combining test and simulation is presented. It combines the testbed for evaluation of low power protocols(TELPP) and TinyOS Simulator(TOSSIM) for protocol evaluation. The design and deployment of the TELPP's hardware and software are realized to carry out the link experiments and energy consumption tests. Finally, the channel model and energy model are estabilished in the tests, and then the whole evaluation framework and its verification and validation are achieved.