SERVOUS: Cross-Technology Neighbour Discovery and Rendezvous for Low-Power Wireless Devices

Cross-technology communication (CTC) supports a direct message exchange between different wireless technologies, enabling explicit interaction between devices with incompatible physical layer (PHY). State-of-the-art work typically
neglects the integration of CTC alongside the native communication stack of a device. As result, current schemes assume that CTC can be carried out at any time and that devices know their neighbours in advance, which is unrealistic or impractical for most duty-cycled low-power wireless systems. In this paper, we fill this gap and present SERVOUS, a cross-technology neighbour discovery and rendezvous protocol allowing a device to autonomously discover and communicate
with surrounding nodes operating on another PHY, while still operating at low duty cycle. SERVOUS reuses a fraction of the radio idle time to discover the presence of
nearby appliances capable of CTC and learns their configuration. It then exploits the Chinese remainder theorem to determine the minimum amount of idle time that needs to be reused to guarantee a cross-technology rendezvous, and can
adjust itself to maximize energy efficiency while satisfying specific application requirements. We base SERVOUS on low-power probing to minimize the channel utilization and integrate it into IEEE 802.15.4 and Bluetooth Low Energy devices
running Contiki. We further evaluate the performance of SERVOUS experimentally and show its ability to let heterogeneous low-power wireless devices interact with each other using CTC, without affecting their native communications.