An opportunistic power-saving mode and scheduler design for wireless local area networks
J. Lee, Catherine Rosenberg, Edwin K. P. Chong · 2006
Minimizing energy consumption is crucial for portable wireless stations because they operate on a limited battery supply. The mechanism called power-saving mode (PSM) allows a network interface on a wireless station to enter the sleep mode whenever possible to reduce its energy consumption. At the same time, there has been a growing popularity in multi-rate wireless systems that can exploit the time-varying nature of the radio environment to increase the overall performance of the system under certain QoS/fairness requirements of users. The primary objective in these so-called systems is to increase the system throughput by giving priority to a mobile station experiencing better channel condition. In this work, we propose an opportunistic Power-Saving Mode and a corresponding scheduler design for wireless local area networks, which improves the energy consumption of PSM stations while maintaining throughput maximization, by exploiting time-varying channel conditions. We identify the challenges in the design and implementation of the PSM and the scheduler. We design a channel probing scheme and a scheduler called OEES (Opportunistic Energy Efficient Scheduler), which considers throughput maximization first and then focuses on minimizing energy consumption. Extensive simulations show that our scheme saves a significant amount of energy while maintaining throughput maximization.