Cell handover algorithm based on prediction in HAPS communication system
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摘要:
在平流层的环境中,高空平台(HAPS)的扰动特性严重影响了通信系统的小区切换性能。在平台扰动和终端移动的场景中,基于固定门限的切换算法容易增加不必要的切换次数,切换性能较差。建立HAPS覆盖模型,用户终端根据其速度动态选择切换检测周期,提出基于接收信号强度差分最小均方预测的自适应切换算法,推导了无线链路失败率的上限。仿真结果表明,相比传统固定门限的切换算法,本文算法有效降低了不必要的切换,同时还可将无线链路失败率控制在1%以下,能够适应多种通信场景。
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关键词:
- 高空平台 (HAPS) /
- 覆盖模型 /
- 预测 /
- 最小均方 /
- 切换
Abstract:In the environment of stratosphere, the quasi-stationary characteristics of high altitude platform station (HAPS) seriously affect handover performance of the communication system. In the scenes of platform disturbance and mobility of terminal, the handover algorithm based on fixed thresholds is easy to increase the number of unnecessary handover and shows poor handover performance. HAPS coverage model was established, and the handover detection period can be changed with speed of user terminals. Then the adaptive handover algorithm was proposed to trigger handover based on signal strength, which is predicted by differential least mean square method. The upper limit of the radio link failure rates was also derived. The results of simulation indicate that compared with traditional fixed-threshold methods, the proposed algorithm effectively reduces the unnecessary handover, and keeps radio link failure rate under 1%, which makes it adaptable to a variety of communication scenarios.
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Key words:
- high altitude platform station (HAPS) /
- coverage model /
- prediction /
- least mean square /
- handover
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表 1 仿真参数列表
Table 1. List of simulation parameters
仿真参数 数值 平台高度/km 22 平台位置变化范围/m 水平±400,垂直±700 平台姿态变化范围/(°) 摆动角±1,偏航角±1 小区波束发射功率/mW 10 蜂窝层数 5 小区半径/km 3.15 频率/GHz 2.1 带宽/MHz 20 路径损耗模型 自由空间损耗,路径损耗指数为2 阴影衰落分布 对数正态分布,标准差为1~5 dB 用户终端速度/(km·h-1) 5~120 用户初始位置 距离小区边缘1 km处 仿真时间/s 200 -
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