Energy Optimization of a Cellular Network with QoS Guarantee

The problem of energy optimization in a cellular network has been studied from different perspectives: sleep patterns, network interference, association of users and base stations, allocation of resources (bandwidth and power), etc. All these aspects have been discussed individually in previous works. However, none of the existing works has succeeded in proposing an accurate solution to an exact mathematical model that takes into account several of these parameters simultaneously. In this work, we propose a modeling of several network parameters (i.e., base station transmission power and activity, user assignment, bandwidth allocation, interference, and data rate) and their interaction in order to minimize the network energy consumption. An exact solution of the proposed model, which solves the energy optimization problem in an LTE network, is presented afterward. The proposed solution guarantees to satisfy all the users with a minimum quality of service (data rate), assuming a proper call admission mechanism has been put in place. The accurate solution allows energy savings of up to 50\% in a moderately loaded network, which leads to energy savings of up to twice than of the heuristic proposed by Piunti \textit{et al.} (2015). Moreover, a strategy to solve the model using column generation method is proposed and investigated. Various numerical results are presented on hexagonal and randomly generated cellular networks