Exploiting Additional Active Time of WiFi Interface to Reduce Power Consumption of Smartphones

Power saving mode mechanism in IEEE 802.11 is designed for reducing power consumption by switching WiFi interface of mobile device between active-state and sleep-state alternately. Since the power consumption in active-state is significantly higher than that in sleep-state, switching between both states should be done carefully; e.g., low priority packets such as delay tolerant packet should not trigger switching to active-state for increasing power saving effect. Delay tolerant traffic, however, also equally affects behaviors of the mechanism since the mechanism is operated within the MAC layer. To overcome this issue, we propose Scrooge which separates delay tolerant traffic from delay sensitive traffic to prevent delay tolerant traffic from impacting on behavior of power saving mechanism. Thus, delay tolerant packets never affect the behavior of power saving mode mechanism. Our prototype implementation improves power saving performance by up to 95% without significant transmission delay under common applications´ traffic patterns.