LoFi: Physical-layer CTC from LoRa to WiFi with IEEE 802.11ax

Low-Power Wide-Area Networks (LPWANs) have emerged as a promising communication technology for facilitating connectivity in the realm of the Internet of Things. A novel LoRa chip has been introduced to provide extensive coverage and energy-efficient support within the 2.4 GHz spectrum. However, establishing a direct connection between Wireless Personal Area Network (WPAN) technologies, such as WiFi, and LPWAN presents challenges due to the inherent asymmetry of the Cross-Technology Communication (CTC) channel. To overcome this obstacle, a novel communication method called LoFi has been introduced. LoFi serves as a cross-technology communication method that enables LoRa devices to establish connections and engage in communication with WiFi-based WPAN networks. A key observation of this study is that when a LoRa frame collides with an ongoing WiFi transmission, the WiFi receiver captures and retains the LoRa data, even post-demodulation within the WiFi hardware. By analyzing the decoded WiFi payload, LoFi can retrieve the LoRa data, and this method remains fully compatible with existing commodity WiFi hardware. Moreover, evaluations conducted using both USRP and commodity devices have demonstrated that LoFi can achieve concurrent wireless communication from LoRa commercial chips to WiFi networks with a frame reception rate exceeding 98 %.