Green Distributed Antenna Systems

Abstract

Energy saving is an important factor which must be taken into account when planning a mobile distribution network. Distributed Antenna System (DAS) is a part of mobile distribution infrastructure which is used to extend the coverage of mobile base stations. DAS is a subject of the present study whose goal is to optimize DAS solutions for indoor and outdoor scenarios in terms of energy consumption while preserving the required Quality-of-Service (QoS). The project outdoor scenario is built on an example of a football stadium (Friends Arena in Stockholm) and the indoor scenario on an example of an office building (Electrum). The propagation model is build under realistic assumptions. The energy efficiency is defined as Joule/bit. Taking into account the radio part only, it is shown that increasing the number of antennas allows to improve the energy efficiency. It is also shown that by adjusting the positions of the antennas using an optimization algorithm, one can further improve the energy efficiency. It is finally shown that taking into account both radio and optical parts, there is an upper bound for the energy efficiency (as a function of the number of antennas), i.e. there is generally an optimal number of antennas which provide the best energy efficiency with a fixed QoS for the system.This thesis is a part of the joint project ¿Green Distributed Antenna Systems¿ between Wireless@KTH, Acreo AB and MIC Nordic AB