The Green Access Technology Of Distributed Antenna System

With the rapid development of the mobile communications market， the energyconsumption of the communications industry showed a rapid growth trend． Thecommunications industry energy conservation is essential，not only to reduce environmentalpollution， but also for enterprises to reduce operating costs． Researchers havemulti-angle-studied the green access technology of wireless communication from timedomain，frequency domain and spatial domain．Distributed antenna system as a kind ofcollaborative communication network is regarded as one of the core technology fornext-generation wireless communication system．The sharp increase in the number of users ofmobile communications makes the traditional cell evolved into micro-cell and pico-cellcovering a radius of just a few hundred meters，which will lead to the cost of networkconstruction and operation．The distributed antenna systems separate antennas from the signalprocessing unit．The antennas of the base station only retain minimal hardware unit．Thesignal will be send back to the base station flat for processing．Thereby，we can reduce thecost and allocate network resources flexibly．The number and position of remote antennas of the distributed antenna system is closelyrelated to the capacity and energy consumption of the entire system．This papers firstly definethe energy efficiency of the system，which is the ratio of ergodic channel capacity and totaltransmit power of the cell．We can use it to measure the green index of the distributed antennasystem．Thereafter，this papers respectively derive theoretical optimal solution of the systemenergy efficiency value with evenly distribute users and unevenly distribute users．The theoryexperimental results show that we can find the optimal number of antennas and accessposition which enables the system to the best energy efficiency value with evenly distributeusers．And when users distribute unevenly，the more the number of antennas are，the betterenergy efficiency value the system can obtain．At the same time，this papers use KMEANSalgorithm to carry out simulation experiments．We obtain similar results compared with thetheoretical results，which verifies the validity of the results．...