Study On Key Technology In Hierarchical Wireless Sensor Network

As the information sensing layer of Internet of things, wireless sensor network (WSN) has a broad application prospect. The key technology of static WSN, such as energy saving, is the current research hot spot. The topic of this paper originates from the items such as NSFC (Natural Science Foundation of China) and National Science and Technology Major Project, and has important theoretical significance and practical significance.In this paper, the energy-saving technology and related protocols are researched in depth, and the following innovative research findings are completed:According to the characteristics of WSN like limited energy, a multi-hop routing protocol of WSN based on double cluster head alternation and compressed sensing (DCHACS) is proposed. In DCHACS, a two-step cluster head selection mechanism is adopted:in first step, a distributed algorithm is used to select the temporary cluster head, and the temporary cluster head utilizes the neighbor cluster optimization algorithm to dynamically adjust the size of the clusters; In second step, local information such as residual energy and location information of nodes is used to re-select better cluster heads. In the data transmission phase, the double cluster head alternation mechanism is adopted to reduce the burden of cluster head, the compressed sensing theory is used to aggregate data, and the cluster head replacement mechanism is adopted to replace old cluster head with the new one under certain conditions. Finally, DCHACS presents an energy-efficient inter-cluster routing algorithm. The simulation results show that DCHACS is able to significantly enhance the clustering performance of network, make the distribution of cluster’s size more uniform, prominently reduce the number of lost packets due to the death of cluster head, and prolong the network’s lifetime.According to the hot spot problem of WSN multi-hop communication, a non-uniform grid partition mechanism based on particle swarm optimization (NuGPM) is proposed. NuGPM adopts the network topology based on grid, and the particle swarm optimization (PSO) algorithm is used to search the best width-combination of grids in all layers. When using the PSO algorithm to solve the optimization problem, NuGPM tactfully constructs the new particle and simplifies the complexity of the algorithm; particle correction algorithm is adopted to make cross-border particles to satisfy the constraint conditions again; The optimal evaluation function and weight coefficient are designed to find the most optimal solution, and balance the lifetime of network as much as possible, so as to improve the hot spot problem of WSN multi-hop communication. The simulation results show that NuGPM is able to balance the energy consumption of whole network, and improve the hot spot problem of WSN multi-hop communication effectively.A cross-layer protocol based on dispatching compensation and topology control (DCTC) is proposed to solve the hot spot problem of WSN multi-hop communication. In DCTC, the network layer adopts the clustering topology based on grid, and MAC layer adopts Time Division Multiple Access (TDMA) mechanism. A simplified lifetime model of grid is used to reduce the complexity of the algorithm. Based on energy balance model and distributed iterative algorithm, DCTC takes comprehensive consideration of cross-layer optimization between network layer and MAC layer, and presents three mechanisms, such as TDMA dispatching compensation, dynamic topology control, and mixed strategy, to precisely calculate the number of compensation time slot and active nodes for every layer grids. The analyzing results show that the three mechanisms proposed in DCTC are able to balance the energy consumption of network with the cost of reducing network’s throughput. The simulation results show that DCTC is able to balance the energy consumption of network, and significantly improve the hot spot problem of WSN multi-hop communication.A network deployment strategy of WSN based on energy balance is proposed. The general model of energy balance is presented firstly. Because the general model utilizes approximation law to calculate the number of nodes which is needed to deploy for every layer grids, the calculation requests loop iteration and is very complicated. Then, the redundant nodes rotation dormancy mechanism is adopted to improve the general model. The improved model of energy balance can reduce the complexity of the algorithm, and obtain the same performance improvement. With the increase of network scale, however, it is need to deploy a large number of redundant nodes in the monitoring area near base station to achieve energy balance. In order to reduce the deployment cost, a suboptimal deployment strategy under constraint condition is presented, and PSO algorithm is used to serch the most optimal number of redundant nodes under onstraint condition. To achieve energy balance under suboptimal deployment strategy, the supplementary deployment strategy and cross-layer optimization mechanism is adopted to further extend the lifetime of network. The simulation results show that the network deployment strategy proposed in this paper is able to improve the hot spot problem of WSN multi-hop communication effectively.Finally, the full text is summarized, and the further research about the hot spot problem of WSN multi-hop communication is prospected.