| As a new information acquisition and processing technology, wireless sensor network has made a wide range of applications in military, environmental monitoring, smart furniture and space exploration and so on. Wireless sensor network can be described as an autonomy system consisting of lots of sensor nodes designed to intercommunicate via wireless radio, and it can collaborate in real-time monitoring, perceiving and collecting information of various environmental or monitoring objects, and transfer this information to the base station. It does not require a fixed network support, and has rapid deployment, survivability, and other characteristics, so it has a very broad application prospect.Wireless sensor network is composed of many sensor nodes which have low power wireless transceiver. Due to the node energy limited, and the node is in a relatively poor environmental commonly, and it does not have energy supplement, so efficient using of energy in wireless sensor network routing protocol is research emphasis. Based on the analysis and study of LEACH protocol, and according to some shortcomings of LEACH protocol, an improved algorithm is proposed in this paperThe improved algorithm is consisted of two algorithms which are new clustering algorithm based on load-balance and residual energy and multi-hop routing algorithm based on Greedy Algorithm. The clustering algorithm based on load-balance and residual energy is to improve the shortcomings of LEACH protocol in cluster head selection, cluster size and single-hop routing, main content are as follows:(1) In the cluster head selection, in addition to the first round of random selection of cluster head, in the later round the most energy cluster node will be selected as cluster head, because the cluster head consumes more energy, and the most residual energy node select as cluster head, so the cluster can realize the load balance.(2) According to shortcoming of single-hop routing, cluster head of the improved algorithm is divided into near cluster head and far cluster head, near cluster head communicate with base station directly, far cluster head communicates with base station through near cluster head, this can avoid long-distance communication that consume large amounts of energy.(3) In the cluster size, in order to avoid load imbalance caused by too many cluster nodes, the improved algorithm make limited at the maximum number of far node cluster and near node cluster. Near cluster head should receive and forward data of far cluster head, so it consumes more energy. In order to further realize load balancing, the maximum number of far node cluster is less than the maximum number of far node cluster.Multi-hop routing algorithm based on Greedy Algorithm is to select communication path between near cluster head and far cluster head, the far cluster head which has the nearest distance with near cluster head is selected as the next hop of near cluster head, the far cluster head which has the nearest distance with far cluster head is selected as the next hop of far cluster head, the far cluster head which has selected as next hop should be marked, and the marked far cluster head can not be selected as next hop again. Until all cluster heads are marked, the multi-hop routing path of near cluster head and far cluster head has selected completed.Finally, LEACH protocol and the improved algorithm simulate in MATLAB, and make Performance analysis and comparison in number of nodes alive, total energy consumption in network and a round of node death distribution. The results show that, compared with LEACH protocol, the improved algorithm prolongs the network life cycle, raises energy utilization and has good load balance. |
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