針對毫微微基地台之LTE行動網路省電機制

Abstract

有效減少行動網路的能量消耗不僅可以為行動網路業者帶來更多的利潤，更符合目前節能減碳的全球趨勢。大型主基地台是行動無線網路的最主要耗能單位，而毫微微基地台(Femtocell Base Station)，具有低功耗，低花費以及使用者自行佈建等優點，如能夠使大部分使用者藉由毫微微基地台取得連線而非主基地台，可以使整體行動網路大幅降低耗電量。 而為了朝綠色通訊邁進，減少主基地台的耗電量是在不遠的將來中最重要的課題。我們認為包含毫微微基地台之兩階層式行動網路將會是減少總能量消耗的最主要架構。在本論文中，我們在此兩階層式的行動網路中發展了一個動態調整網路架構的演算法(GDCA)，根據使用者活動情形來做開關超微型基地台以一種近似於呼吸的開關方式，以求更有效的利用超微型基地台來替代較為耗能的主基地台來服務使用者。 在一定使用者連線品質要求下，GDCA此機制允許毫微微基地台在一定低使用者連線需求的情況下完全的關閉，而在高使用者連線需求的情況下完全開啟服務，如此動態且智能的開關為的就是更能夠有效利用毫微微基地台省電的優勢，來使整體網路架構達到節能的效果。本論文提供完整的分析模型以及細部的節能演算法架構。而模擬結果也顯示我們提出的GDCA演算法能替整體網路架構帶來相當好的省電效果。

Femtocell access points are low-power wireless access nodes connecting standard devices to the core network using broadband digital subscriber line connections. Many literatures already pointed out that most of the energy consumption of current communication networks is due to the contribution of base stations (BSs) and such situation is becoming worse as more base stations are to be deployed to cope with wireless traffic growth. It is thus crucial in the near future to reduce the energy consumption of the base stations for green information and communication technology. A two-tier macro-femtocell network should be the key network architecture to reduce the total energy consumption of these BSs. In this thesis, we develop a green dynamic configuration algorithm (GDCA) in such a two-tier network environment. The GDCA scheme allows a femtocell access point to completely turn itself off, without supporting any communication activity when it is able to save more power. To improve the energy efficiency of femtocell BSs while maintain the required Quallity of services, the GDCA scheme can also intelligently also turn itself on when necessary. A complete analytical model and the detailed power saving algorithm are developed in this thesis. Simulation results show that the proposed GDCA scheme can provide a much better power consumption performance when compared with existing ones.