WiBle: Physical-Layer Cross-Technology Communication with Symbol Transition Mapping

Abstract

Recent advances on Physical-layer Cross-Technology Communication (PHY-CTC) have achieved high throughput direct communication across different wireless technologies. These PHY-CTC works are commonly achieved by emulating the target signal waveform of the receiver. However, signal emulation suffers from inherent unreliability due to imperfect emulation, and it only supports few communication channels. When applied in WiFi to Bluetooth Low Energy (BLE) scenario, it will face two challenges: i) a BLE receiver can not tolerate any bit error in a frame, while emulation errors are easy to appear; and ii) the BLE device performs channel hopping while most BLE channels are unavailable for emulation based CTC.To address these challenges, we present WiBle, a high reliable and all-channel supporting PHY-CTC from WiFi to BLE. The key technical insight of WiBle is symbol transition mapping: When a symbol is transmitted by a WiFi sender and flows into a BLE receiver, it will leave some unique signatures which can be leveraged to extract information. More specifically, it is observed that the phase shifts of BLE received signal can be mapped to the transitions of WiFi symbols. Therefore, by carefully selecting the symbols at the WiFi sender, we can generate the desired phase shifts for correct BLE GFSK demodulation and achieve reliable CTC. Evaluation results on both USRP and commodity chip show that WiBle outperforms state-of-the-art CTCs by higher reliability (> 95% frame reception ratio), wider channel coverage (supporting all 40 BLE channels), and higher throughput (974.3Kbps), under a full range of configurations including indoor/outdoor and LoS/NLoS settings.