A State Transition-Aware Energy-Saving Mechanism for Dense WLANs in Buildings

With the explosive growth of smart terminals, access points (APs) are densely deployed in the buildings of enterprise, campus, hotel, and so on, to provide sufficient coverage and capacity for peak user demands. However, existing studies show that during the off-peak periods, not all the capacity is needed and a large fraction of low-utilization or idle APs cause a great deal of energy waste in these buildings. Although many solutions have been proposed to switch on/off the APs according to the user needs, few works consider the energy cost by state transition. In this paper, we propose a state transition-aware energy-saving mechanism for dense wireless local area networks, which can dynamically switch the APs' states to meet the user needs while controlling the switching frequency and balancing the number of associated users of each AP. First of all, we analyze the most recent user behaviors, which are used to design the energy-saving mechanism. Then, we model the proposed mechanism in order to set relevant parameters reasonably. Finally, evaluation results show that comparing with a typical static strategy, the energy consumption is reduced by 24.3%, and the average available bandwidth is increased by 27.8%. Meanwhile, the switching frequency is reduced by 14.3% as well.