高功率效率小細胞網路的最佳基地台密度之研究

Abstract

基地台布建位置最佳化在各個世代的蜂巢式網路中一直是一個重要的問題。傳統評估蜂巢式網路效能的方法牽涉到大規模的系統模擬。在此篇論文中，我們利用隨機幾何理論，從功率效率的觀點研究單層的小細胞網路。我們推導出了平均用戶傳輸速率與功率效率，並且證實了最大化功率效率的基地台密度是存在的。分析與模擬的結果都指出使用啟動關閉技術的小細胞網路的功率效率顯著地優於全部基地台都啟動的小細胞網路。另外，數值結果顯示平均用戶傳輸速率與功率效率會受到通道衰退效應的影響，但最佳基地台密度卻不易因通道衰退效應而改變。我們所找到的最佳基地台密度對每單位面積要布建多少基地台才能提升功率效率提出洞見。

How to optimally deploy base stations (BSs) in a given area is a long-standing and important problem in each generation of cellular networks. Classical approaches for performance evaluation of cellular networks involves extensive system simulations. In this thesis, using stochastic geometry theory, the optimal BS density of a small cell network with one tier is investigated from a power efficient point of view. The average user rate and the power efficiency for the all-on and on-off power management schemes are derived and the existence of the optimal BS density maximizing the power efficiency for a given user density is verified. Both analytical and simulated results indicate that the on-off power management scheme is significantly superior to the all-on power scheme in terms of power efficiency. In addition, numerical results show that the average user rate and the power efficiency depend on fading conditions, while the optimal BS density is not sensitive to the severity of fading. The optimal BS densities for the two power management scheme provide a good insight on the guideline of how many BSs per unit area should be actively operated or deployed for achieving high power efficiency.