LTE系统中的Mean-OTDOA定位算法

Mean-OTDOA location algorithm in LTE system

由于LTE蜂窝网中远近效应的影响,终端测量到的邻近基站信号的定位参数会存在较大的偏差,导致OTDOA定位方法(到达时间差定位法)估计的终端位置存在较大误差。基于此,提出一种改进的Mean-OTDOA定位算法。首先估计终端与各基站的时延,然后对终端与多基站的距离测量值进行平均,作为OTDOA定位方法中的参考距离,最后利用泰勒级数展开法对终端位置进行估计。仿真结果表明,该算法可提高终端的定位精度,在基站数目为5、测量误差标准差为50 m时,本算法的均方根误差比OTDOA算法降低了5.2039 m,且随着基站数目的增加,定位精度的改善程度优于OTDOA算法。

Near-far effects lead to large deviation of the location factors of neighbor base stations in LTE cellular network measured by terminal,so the terminal location estimated with OTDOA positioning method exists large error.Based on this,this paper proposed an improved Mean-OTDOA location algorithm.Firstly,it estimated the delay between the terminal and the base station,then it averaged the mearsured distance as a reference distance of the OTDOA positioning method,and finally used the Taylor series expansion method to estimate the location of the terminal.Simulation results show this algorithm can improve the positioning accuracy of the terminal.When the number of the base station is 5 and the standard deviation of the measurement error is 50 m,the root mean square error （RMSE） of the proposed algorithm is 5.2039 m smaller than that of OTDOA algorithm,and with the increasing number of base stations,the positioning accuracy are better than that of OTDOA algorithm.