Research On Optimization Of Node Localization Algorithm Based On DV-Hop In Wireless Sensor Networks

Wireless sensor networks(WSNs)have broad application prospects in smart manufacturing,smart home,smart medical care,car networking and smart transportation,smart ecological environment,etc.,and node positioning technology is one of the key technologies of WSNs.The WSNs node positioning algorithm is mainly divided into two categories,which are ranging-based positioning algorithm and ranging-free positioning algorithm.Among them,the traditional DV-Hop positioning algorithm belongs to the positioning algorithm without ranging.The positioning of the unknown node only needs to be estimated based on the average hop distance of the anchor node closer to the distance multiplied by the number of hops.Its estimation is prone to increase positioning error and low positioning accuracy problem.In view of the shortcomings of the traditional DV-Hop positioning algorithm,this paper proposes the following optimization and improvement methods.? In view of the fact that the hop count information in the traditional DV-Hop positioning algorithm is counted as 1 hop,the traditional APIT interior point test has in-to-out and out-to-in misjudgment,and position failure caused by edge effects,etc.,proposes a Node positioning optimization method based on DV-Hop and interior point testing.First,according to the edge effect,when the number of anchor nodes is greater than 3,the node positioning adopts the optimized APIT interior point test algorithm,determines whether the direction of the unknown node and the anchor node are on the same side through the vector cross product,and applies the cosine theorem to calculate the unknown node and the anchor node whether the angle value formed is equal to the sum of the internal angles of the triangle,so as to obtain the precise positioning of the nodes.Secondly,when the number of anchor nodes is less than 3,the node positioning adopts the optimized DV-Hop algorithm,the hop count calculation is optimized by multi-communication radius division,and the average hop distance calculation is weighted.The weighted values are the anchor node hop count,anchor node and unknown Node hops.Finally,according to calculation in three stages,the estimated position of the node is obtained.? Aiming at the problems of low positioning accuracy and large positioning error in the traditional three-dimensional DV-Hop positioning algorithm,a node positioning optimization method based on hop distance and signal strength is proposed.First,optimize the hop count information in the distance vector exchange,calculation the hop count between anchor nodes by constructing the theoretical hop count,correction factor,and calculate the anchor node weight value by calculating the unknown node hop count.Second,estimate the average hop distance and introduce the signal strength RSSI ranging,The distance formula adjusts the corresponding logarithm,performs the first-order partial derivative evaluation,the exact node distance value,the correction factor of the anchor node further optimizes the error value of the theoretical distance and the actual distance.Finally,the weighted minimum is applied according to the calculated values of the first two stages Two times,get the estimated position of the unknown node.The optimized DV-Hop positioning algorithm,traditional DV-Hop positioning algorithm,traditional APIT interior point test positioning algorithm and traditional three-dimensional DV-Hop positioning algorithm were simulated and analyzed in the same environment.The results show that the optimized node positioning method effectively improves positioning accuracy and reduces positioning errors.