Enabling Reliable and Commodity-Device Compatible PHY-CTC From WiFi to ZigBee via Chip Emulation in Phase

Physical layer cross-technology communication (PHY-CTC) is an emerging technique that enables high-speed and direct interaction among incompatible wireless technologies, providing opportunities for spectrum utilization and wireless cooperation among heterogeneous Internet of Things (IoT) devices in the same frequency band. Current PHY-CTC technologies aim to achieve high communication reliability while ensuring compatibility with commodity devices. However, a trade-off exists where either compatibility is sacrificed to achieve high reliability, or compatibility is maintained at the expense of significantly limited communication reliability. Without fulfilling the reliability and compatibility metrics simultaneously, these PHY-CTC technologies are inefficient and impractical to be put into service. This article introduces WibZig, the first highly reliable commodity-device compatible WiFi-to-ZigBee PHY-CTC technology. Due to the similarity of complementary code keying (CCK) codewords supported by 802.11b and ZigBee chips in the phase domain, a cluster of specific CCK codewords is selected to emulate ZigBee symbols. An adaptive processing mechanism is proposed to maintain the phase discontinuity between CCK clusters when constructing an emulated ZigBee packet by modifying the WiFi frames' payload. WibZig requires no hardware modification and is compatible with most commodity devices. We implement WibZig on both USRP and commercial devices. Extensive evaluation under different settings shows that our design improves the PHY-CTC reliability and range by 15\times and 7\times , respectively, over the latest work.