无线传感器网络DV-hop定位算法的改进

Improvement on DV-hop Location Algorithm in WSN

DV-hop算法是无线传感器网络中典型的非测距定位算法,其核心思想是将平均跳距与跳数的乘积作为2个节点间的距离,即采用节点间跳段距离代替实际直线距离参与位置计算。跳段距离计算过程中的误差累计是影响DV-hop算法定位精度的主要因素。本文提出基于门限跳数的信标节点选择策略和基于权的平均跳距优化策略,通过这2种策略减少跳段距离计算过程中的误差累计,提高定位精度。改进后的DV-hop算法通过门限跳数优化信标节点的选取,仅将小于门限跳数的信标节点当作位置计算的有效节点,从跳数角度减少了误差累计;此外,改进后的DV-hop算法在未知节点平均跳距选取上,以最佳跳距替代最近信标节点的平均跳距,更加真实地反映了实际距离,从平均跳距角度减少了误差累计。仿真结果表明,改进后的算法在不同的信标节点数、不同的节点通信半径以及不同的节点稀疏程度下,均能得到更高的定位精度。

DV-hop algorithm is a typical range-free localization algorithm in wireless sensor networks, its core idea is to use the hop count multiplied by the average distance per hop to estimate the distance between two nodes. That is to say, hop distance is regarded as the actual distance in the position calculation. The errors accumulation in the process of hop distance calculation is the main factor on influencing the DV-hop algorithm localization accuracy. The paper presents selection strategy of beacon node based on threshold hop count and optimization strategy of average hop distance based on weight. Those strategies reduce error ac- cumulation in the process of hop distance calculation and improve the positioning accuracy. The improved DV-hop algorithm opti- mizes a scheme for selection of beacon node by threshold hop count. In the scheme, only those beacon nodes whose hop count is less than threshold hop count are used for the position calculation, so error accumulation is reduced from hop count. And for the selection of average hop distance for the unknown node, the algorithm regards optimal hop distance as average hop distance of the nearest beacon node, so error accumulation is reduced from average hop distance. Simulations are performed and the results show that the enhanced DV-hop algorithm greatly improves localization accuracy for different number of beacon nodes, different commu- nication radius and different node density.