平台水平移动对高空平台通信系统性能的影响  

The Effect of the Platform Horizontal Displacement on the Performance of HAP Communication System

作　　者：李树锋[1] 魏急波[1] 马东堂[1] 

机构地区：[1]国防科学技术大学电子科学与工程学院,湖南长沙410073

出　　处：《空军工程大学学报（自然科学版）》2011年第3期73-77,共5页Journal of Air Force Engineering University(Natural Science Edition)

基　　金：教育部博士点基金资助项目(20094307110004)

摘　　要：基于飞艇或飞行器的高空平台(HAP)通信系统面临的一个主要的挑战是平台位置保持。平台保持准静止位置的代价较大。因而,通常建议平台保持在一个位置圆柱内。本文推导终端采用固定指向天线时平台水平最大偏移距离计算公式,并分析有限和无限呼叫持续时间条件下覆盖区蜂窝内呼叫的切换概率。研究表明,平台最大水平偏移距离随着终端波束带宽的增大而增加;相同的波束带宽条件下,平台高度越低,要求的最大偏移距离越小。此外,当最大偏移距离较小时,平台的水平移动只在蜂窝边界附近区域产生切换,且越靠近边界呼叫切换概率越大。蜂窝内平均呼叫切换概率随着平台最大偏移距离的增加而增大;呼叫持续时间内平台移动距离越大,蜂窝内平均呼叫切换概率越大。当呼叫持续时间或平台速度趋于无穷大时,切换概率达到最大值。Platform position maintaining is a major challenge for the airship or aircraft based High Altitude Platform（HAP） communication systems.The platform maintaining a stationary position will introduce a high price.Hence,a position cylinder is suggested for the position maintaining of the platform.This paper derives the computation formula for the maximum distance of the HAP horizontal displacement when a fixed pointing antenna is adopted at the terminal,and simultaneously the handover probability in a cellular of the service area under limited and un-limited average call durations is analyzed.The study results show that the maximum distance for the HAP horizontal displacement increases with the user beam-width.Under the condition of the same beam-width,the higher the altitude of the platform,and the smaller the maximum distance for the platform displacement is required.Moreover,the horizontal displacement can only generate handover in the area near the edge of the cellular.The calls which are nearer to the cell edge have higher handover probability.The average handover probability increases with the maximum distance for the HAP displacement.The larger the HAP displacement during the call duration,the greater the average handover probability is.When the call duration time and the platform speed tend to infinite,the handover probability reaches to the maximum value.

关 键 词：高空平台 切换 水平移动 

分 类 号：TN929.5[电子电信—通信与信息系统]