The Taub Faculty of Computer Science Events and Talks

Contemporary mobile devices are equipped with multiple wireless interfaces, such as WiFi, Bluetooth, WiMax, ZigBee, NFC, etc. All these technologies differ dramatically one from another in maximum transmission range, bandwidth and power demands. Among all subsystems operating inside mobile devices, wireless communication is known as being particularly power-hungry, accounting for 50-70% of the total power consumption in small handheld devices, such as smartphones, and for 10% in laptops. Given the varying characteristics of different wireless technologies, an obvious question arises: Can we utilize the presence of multiple interfaces on contemporary mobile devices in order to improve their wireless networking capabilities in general and power efficiency in particular? In this thesis, we investigate this question from multiple perspectives: theoretical, more practical and fully experimental. On the theoretical side, we formulate a novel optimization problem. A solution to this problem defines a network topology where some devices turn off their power-hungry interface while every device still remains connected to the rest of the network by at least one interface. Through theoretical analysis and practical implementation, we show that the proposed approach achieves significant energy savings, which increase with the size (and the density) of the network. On the more experimental side of our work, we perform a combined power and throughput performance study of WiFi and Bluetooth in smartphones. In the process, we discover several interesting phenomena, some of which counter previous conventions, and draw some operative suggestions for researchers and smartphone developers.