A Centralised Approach to Power On-Off Optimisation for Heterogeneous Networks

The design of centralized algorithms and techniques allowing for an efficient utilisation of infrastructure in terms of energy consumption is one of the key challenges in heterogeneous networks (HetNets). In this study the energy efficiency in the HetNet scenario is formulated as an optimisation problem and an iterative improvement algorithmic approach to power on-off of network cells is devised and evaluated. The algorithm is based on the simulated annealing search approach and the obtained network configuration solutions are compared to a baseline configuration scenario where all cells are powered on. The optimization search is guided by an objective function which is defined on outage throughput and energy efficiency. Simulation results show that significant energy reductions gains can be achieved by switching off macro cells and with no loss of the cell edge user throughput. In some scenarios the algorithm generates solutions which considerably increase network throughput. The gains are more pronounced in configurations where pico cells are deployed at hot zones of user clusters.