Analytical framework for power saving evaluation in two-tier heterogeneous mobile networks

Reducing the power consumption of base stations in mobile networks is an important issue. We investigate the power saving evaluation in two-tier heterogeneous mobile networks which consist of femtocells overlaid by macrocells. In the heterogeneous mobile networks, base stations without traffic load are allowed to enter the sleep mode to save power. The power saving probability that a base station enters the sleep mode and the average total power consumption of this network are complex joint-effects of various factors. Successful modelling of these complex joint-effects is critical to mobile network operators when they pursue the design of green mobile networks. In this paper we propose an analytical framework to facilitate systematic analysis. Based on the proposed analytical framework, we investigate the power saving probabilities and the average total power consumption in terms of several parameters, including the new traffic arrival rate per user, the maximum transmission power of a femtocell, the number of femtocells within a macrocell, and the number of users in the network. Numerical results show that the proposed analytical framework provides a useful and efficient method to facilitate systematic analysis and design of green mobile networks. Simulation results validate the accuracy of the proposed analytical framework.