BlueSky: Realizing Buried Potential of Bluetooth to Sustain a Large-scale Multi-hop Network

Abstract: Traditionally, Bluetooth has been deemed unsuitable for sustaining a large-scale multi-hop network. There are two main reasons: severe frequency channel collisions under a large-scale network and high complexity of designing an efficient formation protocol. In this work, we reconsider this viewpoint from a practical usability perspective and aim to realize the buried potential of Bluetooth. Firstly, we find that the collision probability under a low-overhead network is fairly small, which is acceptable for practical applications. Secondly, we propose BlueSky, a complete system solution to provide necessary networking functionalities for Bluetooth. In BlueSky, we develop a connection maintenance mechanism for mitigating the influence of collisions and a network formation protocol for reliable packet transmissions. We implement BlueSky on Windows Mobile using 100 commercial smartphones. Comprehensive usability evaluations demonstrate the negligible overheads of BlueSky and its good network performance. In particular, 90%-95% of the whole 100 nodes can participate in the communication smoothly.