Power-saving strategy for balancing energy and delay performance in WLANs

In wireless local area networks (WLANs), power conservation for mobile devices is considered as one of the most important issues because it effectively prolongs the battery life of mobile devices. The IEEE 802.11 standard specifies a power-saving mode that allows mobile nodes to adaptively operate in sleep and wake modes to reduce the overall energy consumption. In the IEEE 802.11 power-saving mode, the access point (AP) can adjust the number of nodes in wake mode at every beacon interval. In this paper, we first investigate how the number of nodes in wake mode affects both energy consumption and delay performance in WLANs. We then propose a balanced power-saving strategy, which determines an appropriate number of nodes in wake mode based on a trade-off between energy consumption and packet delay. Through a performance analysis and extensive simulations, we show that our proposed scheme effectively reduces overall energy consumption while retaining low packet delay.