Wi-FM: Resolving Neighborhood Wireless Network Affairs by Listening to Music

摘要

FM radio, typically broadcast in the 87.5 to 108.0Mhz range, is widely available in urban areas and beyond. Contrary to GPS, it effectively penetrates buildings, contrary to 3G/4G or TV, FM radio receivers are becoming freely available in mobile devices. Indeed, nearly every smart phone and many other consumer electronics today have a built-in FM chip. In this paper, we demonstrate that this ubiquitous in-the-air and on-device FM radio availability presents a unique opportunity to address some of the fundamental wireless networking problems. In particular, we focus on the problem commonly arising in home networks where devices from neighboring, yet autonomous and non-collaborative, Wi-Fi networks systematically "step on each other's feet", i.e., interfere and degrade each other's performance. We show that the digital signal that accompanies broadcast FM radio has sufficient structure to enable effective scheduling relative to it. It thus provides a common reference for neighboring devices to harmonize their transmissions, yet without requiring any explicit communication among them. To the best of our knowledge, our system is the first to enable such mutually-beneficial, autonomous, and implicit harmonization among Wi-Fi devices across administrative network bounds.