Distributed power on-off optimisation for heterogeneous networks - A comparison of autonomous and cooperative optimisation

The design of distributed algorithms and techniques allowing for an efficient utilisation of infrastructure in terms of energy consumption is one of the key challenges in heterogeneous networks or 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 network is divided into clusters of cells, and the algorithm, which employs simulated annealing search, is executed by the clusters in a distributed manner. Four different variations of autonomous and cooperative optimisation are devised 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 the distributed cooperative algorithms perform better than the baseline in nearly all cases both in terms of outage throughput and energy efficiency. Furthermore, coordination among clusters has a strong impact on the speed and the performance of the obtained solutions.