具覆蓋率限制異質性小細胞網路之功率控制

Abstract

本論文的主旨在開發一個異質性無線網絡的模型和分析架構，其功率控制法具有 針對不同情況相應的一些可適性策略以利實際的複雜環境。為了評估網路覆蓋率以 及不同環境下的平均頻譜效能，在本論文中，我們模擬了一個由多層基地台和分散 用戶組成的異質性網路。在每個不同的用戶連結機制以及具有功率控制的環境下， 每層基地台中的閒置基地台機率、網路覆蓋率的緊下界、平均頻譜效率都被推導而 出。此外，我們還進一步發現功率傳輸量以及基地台之間的直接關係，其給予建造 者達到其覆蓋率約束的期望。換句話說，它不僅節省了功率，也減少了在相應功率 控制策略下我們需要的基地台之數量。最後，我們通過使用異質性網路中的功率控 制，將我們以前的建模和分析架構應用於具有閒置基地台考量的蜂窩網絡，並提供 數值模擬和數學表示以驗證我們的發現。我們最後也得出結論，哪種類型的環境將 適合我們的功率控制方案，這可以作為一些研究人員嘗試在蜂窩網絡進行功率控制 時的建議。

In this thesis, we develop a general modeling and analyzing framework for a heterogeneous wireless network (HetNet) which has some power control strategies for different situations to adapt the complex environment in practice. In order to evaluate the link coverage and the mean spectrum efficiency in different environment, we consider a HetNet consisting of multiple tiers of BSs and randomly distributed users. In each user association scenario, the void probabilities of the BSs in each tier are found and the tight lower bounds on the link coverage and the mean spectrum efficiency by using power control with coverage constraints are all derived. Furthermore, we also find the relationship between the transmit power and the density of BSs, which gives the builders a guideline to achieve their coverage constraint. In other words, it not only saves power but also reduces the number of BSs we need under corresponding strategies. Finally, we apply our previous modeling and analysis framework to the HetNet with the void cell phenomenon by using power control in the HetNet and provide the numerical simulations and mathematical representation to validate our findings. We also conclude that which kind of environment would be suitable for our power control scheme, which can be viewed as an advice for some researchers trying to apply power control in HetNets.