蜂窝网络中用户移动参数对越界率的影响

INFLUENCE OF PARAMETERS IN USER MOBILITY MODELS UPON CELL-CROSSING RATE IN A CELLULAR NETWORK

越界率是衡量无线蜂窝网络性能的重要指标之一。主要考察用户移动模型中3个要素(速度、方向和蜂窝小区的信号覆盖范围)对用户越界率的影响。这种影响的检测是分别在简单移动模型和支持突发事件影响的移动模型上进行多组实验所得的,分别画出了两种移动模型下用户最大速度、最小速度以及平均速度的变化、BS的信号覆盖范围和用户移动方向改变频率与用户越界率之间的曲线图。通过对比两种不同移动模型下的实验数据,发现用户的越界率与用户的移动速度和BS的信号覆盖范围关系较大,而用户移动方向的改变频率对越界率的影响相对较弱。

Cell-crossing rate is one of the most important criteria for measuring wireless cellular network performance.In this paper we mainly investigate the impact of three essential factors in user mobility model（speed,direction and signal coverage of cellular base station-BS） on the crossing rate.Two mobility models are used in detecting such impacts,the simple mobility model（SMM） and the mobility model with effect of unexpected event（MM/EUE）,and the results are obtained from a couple of experiments.From the results we draw the plotted curves with regard to two kinds of mobility models respectively,they reflect the maximum speed,minimum speed and average speed variation of users,and the relationship between users cell-crossing rate and signal coverage of BS and the frequency change of user＇s moving direction.Through comparison on the experimental data derived from two different mobility models,a conclusion could be drawn that the users crossing rate is closely related to user＇s moving speed and signal coverage of BS,while the impact of frequency change of user＇s moving direction on crossing rate is relatively weaker.