D2D Relay Assisted BSs ON/OFF Switching for Energy Saving in Dense Small Cell Networks

• Main Authors: Rui-yu Chen, 陳瑞俞
• Other Authors: Wei-Kuang Lai
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/rqpx5s

碩士 === 國立中山大學 === 資訊工程學系研究所 === 107 === The deployment of small cells seems a promising and inevitable trend to satisfy the increasing traffic demands. In fact, the deployment of dense small cells in hot spot area plays a key role in frequency reuse enhancement in 5G scenarios. Although the energy consumption of a single small cell is much less than a single large-scale base station, the considerable number of non-stop small cells will still cause huge energy consumption. The OPEX (Operation Expenditure) is a heavy burden for operators. And the carbon footprint is not eco-friendly. Thus, ITU (International Telecommunication Union) proposed the concept of green communication. The main purpose is to reduce the energy consumption in both manufacturing and operating of the huge energy required telecommunication industry. In traditional cellular network environments, the traffic demands have the characteristics of spatial and temporal fluctuations since users will move separately or get together. In light load scenarios, all the BSs (Base Station) require staying active and will lead to unnecessary energy consumption. Different from previous studies, this thesis is based on the small cell switching on/off mechanism proposed by 3GPP (Third Generation Partnership Project) combining relay techniques. This thesis proposed CIR (Capacity Improvement Relay) and CER (Coverage Extension Relay) algorithm to increase the opportunity for BSs to switch off. CIR aims to enhance the RBs efficiency to reserve more RBs for offloading neighbor cell’s load. CER aims to extend service coverage and assemble loads from neighbor cells. In light load environments, about 45% of BSs can be turned off through CER. In medium load, the inefficient allocation with only cellular mode will deplete RBs in BSs faster. With CIR, more remaining RBs provides more space to grab users from light load neighbor BSs. The final switched off BSs ratio remains at 25%. In high load, even if no BSs can be turned off, the final user satisfied ratio is higher than purely CUE mode because of allocating RBS efficiently with CIR.