Demystifying 802.11n Power Consumption

This paper report what the authors believe to be the first measurements of the power consumption of an 802.11n NIC across a broad set of operating states (Channel width; transmit power, rates, antennas, MIMO streams, sleep, and active modes). The authors find the popular practice of racing to sleep (By sending data at the highest possible rate) to be a useful heuristic to save energy, but that it does not always hold. This paper contributes three other useful heuristics: wide channels are an energy-efficient way to increase rates; multiple RF chains are more energy-efficient only when the channel is good enough to support the highest MIMO rates; and single antenna operation is always most energy-efficient for short packets.