Taming the power hog in wireless broadband access

Lin Zhong

Advancement in wireless and semiconductor technologies has equipped modern mobile devices
with wireless broadband access. Yet wireless broadband interfaces are among the largest power
consumers on mobile devices, which are constrained in both battery lifetime and heat dissipation
capability.

While extensive research has addressed this with network solutions, we have recently investigated
complementary, system solutions. In this talk, we will begin with an analysis of the fundamental ways
modern wireless broadband access wastes energy. We then present our recent research results in
addressing three of such wastes. First, we demonstrate that 802.11 interfaces can enter power-saving
modes even during active data communication to reduce temporal waste. Second, we present a
multi-antenna system that reduces directional waste with directional antennas. Finally, we show that
context information can be employed to judiciously combine multiple wireless interfaces with
complementary power characteristics to reduce protocol waste. We intend these techniques to be
implemented in wireless network interfaces and to require no change or cooperation from the network
infrastructure.