| As a kind of wireless self-organizing network developed by the end of the 20 th century,the wireless sensor network is a transmission technology integrating sensor technology,micro-electro-mechanical system technology,wireless communication technology,embedded computing technology and distributed information processing.Compared with the traditional public network communication technology,the wireless sensor network is widely applied to the fields of military,medical,agriculture,environment,intelligence and the like in the characteristics of task or data as the center and is easy to arrange,low in energy consumption,low in cost,convenient to control and the like.In the field of farmland,the traditional data acquisition on the basis of manual collection and cable has been unable to meet the demand of agricultural production in real-time,accuracy and convenience.The combination of the wireless sensor network technology and the application of the agriculture field is an important driving force to promote the transformation of modern agriculture.Therefore,it is an important research field to design and optimize the structure of wireless sensor network.In view of the characteristics of farmland monitoring environment,such as special deployment,large scale and complex influence of environmental factors on crop growth,this paper takes LEACH protocol,which is the core protocol of hierarchical routing protocol in wireless sensor networks,as the research object,and improves the protocol adaptively from the aspects of network modeling,node type,cluster head selection and its rotation mechanism,routing algorithm and so on.The main research results are as follows:(1)When crops grow in the farmland environment,their growth conditions are affected by various environmental factors.Therefore,this paper sets up different types of sensor nodes during the initialization of the network,and simulates the energy consumption algorithm under different parameters generated by sensor nodes of different orders of magnitude in practical applications.(2)Due to the growth characteristics of crops,the farmland environment is usually arranged in the planting area regularly.The density and number of sensor nodes in the area will affect the quality of data collection.Therefore,the network is divided into uniform virtual grids according to the scope of farmland monitoring,and the nodes of each cluster are uniform by grid fusion.(3)After studying the characteristics of LEACH protocol in cluster head election algorithm,we find its shortcomings and make improvements.In the new cluster head election,the residual energy,node density and node center degree are taken into account,and the probability of cluster head election is determined from three aspects.The rotation mechanism of cluster head takes into account the residual energy of the current cluster head node,which improves the reuse rate of the node.Combined with the form of virtual lattice,the energy consumption caused by control information transmission between nodes can be effectively reduced.(4)The biggest characteristic of farmland environment is large scale and wide distribution of crops.The single hop transmission mode between LEACH protocol cluster head and base station not only consumes energy,but also is unreliable transmission.Therefore,a multi-hop transmission based on greedy algorithm between nodes in stable point stage is designed,in which the peripheral algorithm of jumping out of routing hole is improved.Finally,considering the disadvantages of the surrounding algorithm,an algorithm to avoid routing voids is designed,and the ordinary node is introduced to replace the cluster head node to participate in the multi-hop algorithm.The algorithm makes the data transmission effective communication,saves energy consumption and improves the network life cycle. |
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