Sleeping mobile AP: a novel energy efficient Wifi tethering scheme

Wifi tethering enables Wifi-only devices to access the Internet by sharing the WWAN (e.g., 3G and LTE) connection of a smartphone where there is no available Wifi access point. However, the current tethering schemes have a limitation as they consume a significant portion of the battery power for providing Wifi clients with the Internet connection. In this paper, we propose a new tethering scheme that reduces the energy consumption of a mobile AP (MAP) without substantial throughput and delay degradation. To improve energy efficiency, the proposed scheme adaptively adjusts the sleep and wake-up periods based on the bandwidth asymmetric feature of the MAP. Further, it provides a longer idle time enough to put the clients into a sleep mode by combining idle periods between subsequent packets, and conserves their energy as well. Our evaluation based on the prototype implementation on commercial smartphones shows that the proposed scheme reduces the energy consumption of the MAP and the client smartphones by up to 56.0 and 8.3 %, respectively.