Energy Efficient Network Organization Technology In Heterogeneous Network

In recent years, the rapid proliferation of internet-connected smart devices has led to an explosive surge in mobile data traffic, which increase both capital and operational expenses, particularly the cost of energy, and greenhouse gas emissions. Pushed by such needs of energy reduction, topics of energy efficiency (EE) have thus attracted wide attentions. Thus, this paper focuses on the EE network organization technology in heterogeneous cellular network (HCN), including large-scale network deployment (such as network planning, base station(BS) deployment optimization) and small-scale wireless resource management technology and optimization (such as resource allocation,cell association strategy and interference coordination strategy). The specific research contents are as follows:Firstly, this paper considers the energy efficient network deployment strategy and focuses on minimizing the area power consumption (APC)under the constraints of rate coverage. Firstly, the relationship between signal interference noise ratio (SINR) coverage, rate coverage, power consumption and the BS deployment density of the system is deduced.Then, based on the obtained theoretical results, the closed-form expressions of the rate coverage probability and optimal BS density for each tier are derived. Both the analytical and simulation results show that larger energy saving is possible by appropriately biasing the HCN deployment.Secondly, this paper studies the EE-oriented partial spectrum reuse(PSR) scheme, aiming at minimizing the network energy cost under the constraints of SINR coverage, delay and downlink rate. In addition,backhaul is the bottleneck of small cell performance, and thus we take it into consideration. Specifically, this paper first derives the total expected delay for a typical user by considering retransmissions over the wireless link, as well as the backhaul delay incurred from wired backhaul.Furthermore, this paper minimizes the whole delay experienced by the users from the perspective of small cell density. Then we get the optimized density and PSR factor of small base station by joint solution.Both the analytical and simulation results show that significant energy saving can be achieved through tolerable sacrifice of delay performance with careful designs according to our analysis.Finally, focusing on the load unbalance as well as the severe inter-tier interference problems, this paper studies small-scale interference coordination strategy based on EE. We propose a novel framework to analyze EE with joint low power transmission, user association and resource partitioning in a two-tier HCN. This work offers some valuable insights and guidelines on optimal system performance for practical network design.