LEGO-Fi: Transmitter-Transparent CTC With Cross-Demapping

Abstract

Cross-Technology Communication (CTC) is an emerging technique that enables direct communication across different wireless technologies. The state-of-the-art works in this area propose physical-level CTC, in which the transmitters emulate signals that follow the receiver's standard. Physical-level CTC means considerable processing complexity at the transmitter, which does not apply to the communication from a low-end transmitter to a high-end receiver. This article proposes LEGO-Fi, which supports the CTC from ZigBee to WiFi and Bluetooth to WiFi. LEGO-Fi is a transmitter-transparent CTC technique, which leaves the processing complexity solely at the receiver side and therefore, makes a critical advance toward bidirectional high-throughput CTC. The key technique inside is cross-demapping, which stems from two key technical insights: 1) a ZigBee/Bluetooth packet leaves distinguishable features when passing the WiFi modules and 2) compared to ZigBee's/Bluetooth's simple encoding and modulation schemes, the rich processing capacity of WiFi offers extra flexibility to process a ZigBee/Bluetooth packet. The evaluation results show that LEGO-Fi achieves a throughput of 213.6 Kb/s in practice, which is, respectively, 13000×, 1200×, and 7.5× faster than FreeBee, ZigFi, and SymBee, the three existing ZigBee-to-WiFi CTC approaches. For the CTC from Bluetooth to WiFi, LEGO-Fi achieves a throughput of 904.1 Kb/s.