The continual proliferation of mobile devices has stimulated the development of opportunistic encounter-based networking and has spurred a myriad of proximity-based applications. These devices are envisioned as an increasingly important information interface between neighboring users. A primary cornerstone of such applications is to build up a bridge connecting devices efficiently and effectively. In this thesis, we address two challenging topics in this area named neighbor discovery and spatial-awareness device interaction. In the first work, we design a deterministic neighbor discovery protocol named BlindDate for both asynchronous symmetry problem and asynchronous asymmetry problem. Through theoretical analysis and extensive experiments, BlindDate is shown to guarantee a discovery...[ Read more ]

The continual proliferation of mobile devices has stimulated the development of opportunistic encounter-based networking and has spurred a myriad of proximity-based applications. These devices are envisioned as an increasingly important information interface between neighboring users. A primary cornerstone of such applications is to build up a bridge connecting devices efficiently and effectively. In this thesis, we address two challenging topics in this area named neighbor discovery and spatial-awareness device interaction. In the first work, we design a deterministic neighbor discovery protocol named BlindDate for both asynchronous symmetry problem and asynchronous asymmetry problem. Through theoretical analysis and extensive experiments, BlindDate is shown to guarantee a discovery latency of 9/10(1+δ)²x² where δ is a small fraction of slot length and 1/x is the duty cycle, which advances the state-of-the-art in both average performance and worst-case bound. In the second work, we are enlightened by the fact that neighboring devices share similar ambient information as they are spatially close. Thus, we design a novel neighbor discovery protocol named AIR. AIR exploits ambient acoustic information to complete neighbor discovery in shorter time. Using low power acoustic sensing, our protocol substantially increases the probability of devices discovering each other the first time they turn the radio on, which significantly decreases the average discovery latency. In the third work, we propose a novel system for initiating device interactions in close proximity with zero prior configuration. We utilize built-in microphones and speakers on commodity devices for the purpose of initiating device interactions by a simple waving gesture. Our experimental results show its feasibility and potential to be applied on applications ranging from Person-to-Person interactions to Person-to-Device interactions.