A MAC Layer Dynamic Power Management Scheme for Multiple Users in a WLAN

To prolong the lifetime of battery powered wireless devices, standard protocols for WLANs have the provision for such devices to transition to a "sleep" state periodically. Being in the "sleep" state entails minimal power consumption by a wireless device but it also increases the average packet delay that the device encounters. This paper proposes a simple, centralized, dynamic, scalable and adaptive algorithm to optimize the duration of sleep states of wireless nodes operating in the infrastructure mode in a WLAN, with the objective of minimizing their power consumption with respect to a QoS constraint namely average packet delay. The algorithm dynamically adjusts the sleep duration of a node to its average packet arrival rate and its average packet delay constraint. The performance of this algorithm is compared with a common power saving protocol implemented in WLANs like 802.11, namely, a static sleep mechanism where the sleep duration of a devise is set to be equal to the average delay constraint of the devise. Simulation results prove the power efficiency of the adaptive sleep algorithm over the static sleep scheme especially for non uniform traffic.