Tagcaster: Activating Wireless Voice of Electronic Toll Collection Systems With Zero Start-Up Cost

• Published in: IEEE/ACM transactions on networking 2022-10, Vol.30 (5), p.2328-2342
• Main Authors: An, Zhenlin, Lin, Qiongzheng, Yang, Lei, Xie, Lei
• Format: Article
• Language: English
• Subjects: Automobiles; Costs; cross-technology communication; E-Toll collection; Frequency modulation; IoT; Radiofrequency identification; Receivers; RFID; Transponders; User experience; Vehicles
• ISSN: 1063-6692; 1558-2566
• DOI: 10.1109/TNET.2022.3169914

This work enhances the machine-to-human communication between electronic toll collection (ETC) systems and drivers by providing an AM broadcast service to deployed ETC systems. This study is the first to show that ultra-high radio frequency identification signals can be received by an AM radio receiver due to the presence of the nonlinearity effect in the AM receiver. Such a phenomenon allows the development of a previously infeasible cross-technology and cross-frequency communication, called Tagcaster, which converts an ETC reader to an AM station for broadcasting short messages (e.g., charged-fees and traffic forecast) to drivers at tollbooths. The key innovation in this work is the engineering of Tagcaster over off-the-shelf ETC systems using shadow carrier and baseband whitening without the need for hardware nor firmware changes. This feature allows zero-cost rapid deployment in the existing ETC infrastructure. Two prototypes of Tagcaster are designed, implemented, and evaluated over four general and five vehicle-mounted AM receivers (e.g., Toyota, Audi, and Jetta). Experiments reveal that Tagcaster can provide good-quality (PESQ>2) and stable AM broadcasting service with a 30 m coverage range. Tagcaster remarkably improves user experience at ETC stations, and two-thirds of volunteer drivers rate it with a score of 4+ out of 5.