WiZig: Cross-Technology Energy Communication Over a Noisy Channel

Abstract

The proliferation of IoT applications brings the demand of ubiquitous connections among heterogeneous wireless devices. Cross-Technology Communication (CTC) is a significant technique to directly exchange data among heterogeneous devices that follow different standards. By exploiting a side-channel like frequency, amplitude, or temporal modulation, the existing works enable CTC but have limited performance under channel noise. In this article, we propose WiZig, a novel CTC technique from WiFi to ZigBee that employs modulations in both the amplitude and temporal dimensions to optimize the throughput over a noisy channel. We establish a theoretical model of the energy communication channel to clearly understand the channel capacity. We then devise an online rate adaptation algorithm to adjust the modulation strategy according to the channel condition. Based on the theoretical model, WiZig controls the number of encoded energy amplitudes and the length of a receiving window, so as to optimize the CTC throughput. We implement a prototype of WiZig on a software radio platform and a commercial ZigBee device. The evaluation shows that WiZig achieves a throughput of 153.85bps with less than 1% symbol error rate in a real environment.