Date of this Version
Qi Xia (2019). FEASIBILITY AND SECURITY ANALYSIS OF WIDEBAND ULTRASONIC RADIO FOR SMART HOME APPLICATIONS (master's thesis). University of Nebraska-Lincoln, USA.
Smart home Internet-of-Things (IoT) accompanied by smart home apps has witnessed tremendous growth in the past few years. Yet, the security and privacy of the smart home IoT devices and apps have raised serious concerns, as they are getting increasingly complicated each day, expected to store and exchange extremely sensitive personal data, always on and connected, and commonly exposed to any users in a sensitive environment. Nowadays wireless smart home IoT devices rely on electromagnetic wave-based radio-frequency (RF) technology to establish fast and reliable quality network connections. However, RF has its limitations that can negatively affect the smart home user experience and even cause serious security issue, such as crowded spectrum resources and RF waves leakage. To overcome those limitations, people have to use technology with sophisticated time and frequency division management and rely on the assumptions that the attackers have limited computational power. In this thesis we propose URadio, a wideband ultrasonic communication system, using electrostatic ultrasonic transducers. We design and develop two different types of transducer membranes using two types of extremely thin materials, Aluminized Mylar Film (AMF) and reduced Graphene Oxide (rGO), for assembling transducers, which achieve at least 45 times more bandwidth than commercial transducers. Equipped with the new wideband transducers, an OFDM communication system is designed to better utilize the available 600 kHz wide bandwidth. Our experiments show that URadio can achieve an unprecedentedly 4.8 Mbps data rate with a communication range of 17 cm. The attainable communication range is increased to 31 cm and 35 cm with data rates of 1.2 Mbps and 0.6 Mbps using QPSK and BPSK, respectively. Although the current wideband system only supports short-range communication, it is expected to extend the transmission range with better acoustic engineering. Also, by conducting experiments to measure the ultrasonic adversaries' eavesdropping and jamming performance, we prove that our system is physically secure even when exchanging plaintext data.
Adviser: Qiben Yan