Along the line of enabling terahertz communication using leaky-wave antennas, another major activity in the past year is exploring the sensing capability of leaky-wave antenna for communication critical mobility information including nodal (translation, rotation) and environmental mobility (blockage). Due to the high directionality of terahertz link, link adaptation is required to maintain beam alignment when the device moves or encounter blockage. We present LeakyTrack, a novel system that enables non-coherent and training-free motion sensing with a single antenna which exploits leaky-wave antenna’s unique frequency signatures to extract nodal movement and object blockage information. we devise a model that allows a leaky-wave antenna equipped receiving node to locally predict its angular location and orientation relative to a leaky-wave transmitter, as well as estimating the size of the blockage object. We implement the key components of LeakyTrack and perform extensive over-the-air experiments in various settings, showing good matching between the model we devise and experimental results.
We first studied the range of parameters that can be sensed using a leaky-wave antenna at the transmit node of a point-to-point wireless link. This work builds on our earlier publications in Nature Communications, in which we demonstrated that a system in which both transmitter and receiver have leaky-wave antennas can employ a single broadband pulse to ascertain both the angle of arrival and angle of departure, simultaneously. Here, we developed an automatic detection system, termed LeakyTrack, which can extract this information directly from measured spectra, in order to obtain information about client motion, as well as the size and motion of objects causing transient blockage of the line-of-sight beam. This approach emphasizes the unique combination of sensing and communications that can be accomplished with a single node architecture, which highlights the urgent need for such sensing capabilities in future THz networks. These results were developed via close collaborations between the two research groups, including data collection in Mittleman’s laboratory by students from both research groups as part of a temporary graduate student exchange. The paper was presented (virtually) at SenSys 2020.
Publications
Y. Ghasempour, C.-Y Yeh, R. Shrestha, Y. Amarasinghe, D. Mittleman, and E. Knightly, “LeakyTrack: Non-Coherent Single-Antenna Nodal and Environmental Mobility Tracking with a Leaky-Wave Antenna,” in Proceedings of the 18th ACM Conference on Embedded Networked Sensor Systems (SenSys ’20), 56–68 (2020).