Poster: Bidirectional Physical-Layer CTC between Wi-Fi and BLE COTS devices

Bidirectional Cross-technology Communication (CTC) between WiFi and BLE demonstrates a wide range of applications prospects, such as temperature/humidity monitoring in smart home, LE-Audio relaying by WiFi APs, etc. However, existing CTC techniques between WiFi and BLE only support one-way transmission and are unable to be implemented on Commercial Off-The-Shelf (COTS) devices. This paper proposes BiCross, a bidirectional CTC scheme between WiFi and BLE which requires only software update on COTS devices. In essence, BiCross first presents a channel-specific symbol mapping technique to support all-channel reliable downlink CTC for BLE channel hopping. Then, BiCross leverages the spectrum scan capacity of WiFi Network Interface Cards (NICs) and analyzes the spectral characteristics of BLE frames to achieve uplink CTC. Finally, BiCross solves the problem of discontinuous and uncertain interval of spectrum analysis on commodity WiFi NICs through the design of BLE payload symbols and CRC-based error correction. The evaluation results demonstrate that BiCross achieves high reliability (downlink FRR > 95%, uplink FRR > 90%) and high throughput (downlink 854kbps, uplink 732kbps), and we showcase the application of BiCross on temperature acquisition in smart home scenario.