The smart buildings of the future need to understand the movement and occupancy of the people in the environment. Using cameras to provide this context can be privacy-invasive. Alternatively, installing dedicated hardware to sense the environment can be cost-prohibitive and limit ubiquitous adoption. WiFi-based sensing has hence been championed to provide this building-scale sensing, as it allows for both privacy and is ubiquitously deployed in most buildings. However, industry-translatable research in this space has been challenging as no building-scale systems can provide WiFi sensing data. Consequently, many real-world challenges of deploying these sensing systems remain a mystery. To overcome this veil of mystery, we develop and open-source WiSenseHub, a building-scale WiFi-sensing system. We build our system on commercially available WiFi radios, deploy our backend services to collect data on infinitely scalable AWS cloud or a local server desktop, and build a front-end phone-based interface to collect diverse WiFi sensing data. We deployed multiple WiFi radios in our building and collected data for user devices for over 38 hours.

Interest in autonomous navigation and exploration for indoor applications has spurred research into indoor Simultaneous Localization and Mapping (SLAM) robot systems. While most of these SLAM systems use camera and LiDAR sensors in tandem with an odometry sensor, these odometry sensors drift over time. Visual (LiDAR/camera-based) SLAM systems deploy compute and memory-intensive search algorithms to detect 'Loop Closures' to combat this drift, making the trajectory estimate globally consistent. Instead, WAIS (WiFi Assisted Indoor SLAM) demonstrates using WiFi-based sensing can reduce this resource intensiveness drastically. By covering over 1500 m in realistic indoor environments and WiFi deployments, we showcase 4.3× and 4× reduction in compute and memory consumption compared to state-of-the-art Visual and Lidar SLAM systems. Incorporating WiFi into the sensor stack improves the resiliency of the Visual-SLAM system. We find the 90th percentile translation errors improve by ~ 40% and orientation errors by ~ 60% compared with purely camera-based systems. Additionally, we open-source a toolbox, WiROS, to furnish online and compute efficient WiFi measurements.

RF signals can be leveraged for many sensing and monitoring tasks in industrial, home, or robot applications. Despite the advantages of leveraging WiFi sensing modality, no versatile WiFi sensors are available. We develop WiROS to address this immediate need. We leverage the robot operating system (ROS) framework to expose real-time WiFi sensing information to an end-user. Specifically, we demonstrate a plug-and-play toolbox providing access to coarse-grained WiFi signal strength (RSSI), fine-grained WiFi channel state information (CSI), and other MAC-layer information (device address, packet id’s or frequency-channel information). Additionally, we opensource state-of-art algorithms to calibrate and process WiFi measurements to intuitively visualize/debug measurements and measure signal path parameters like the signal’s angles of arrival or departure.

Modern data centers leverage large FPGAs to provide low latency, high throughput, and low energy computation. FPGA multi-tenancy is an attractive option to maximize utilization, yet it opens the door to new security threats. In this work, we develop a remote classification pipeline that targets the confidentiality of multi-tenant cloud FPGA environments. We utilize an in-fabric voltage sensor that measures subtle changes in the power distribution network caused by co-located computations. The sensor measurements are given to a classification pipeline that is able to deduce information about co-located applications including the type of computation and its implementation. We study the importance of the trace length and other aspects that affect classification accuracy. Our results show that we can determine if another co-tenant is present with 96% accuracy. We can classify with 98% accuracy whether a power waster circuit is operating. Furthermore, we are able to determine if a cryptographic operation is occuring, differentiate between different cryptographic algorithms (AES and PRESENT) and microarchitectural implementations (Microblaze, ORCA, and PicoRV32).

Side-channel leakage poses a major security threat in multi-tenant FPGA environments. One tenant can instantiate a voltage fluctuation sensor that measures minute changes in the power distribution network (PDN) and infer information about co-tenant computation and data. This work presents the Tunable Dual-Edged Time-to-Digital Converter (TDC) - a voltage fluctuation sensor with two unique elements: first, it has the ability to tune the sample duration, phase, and frequency to more effectively extract information about the co-located computation; second, it captures both rising and falling transitions which provides unique information about the target computation.

Side channels which introduce intra-device circuit module information leakage or functional influence are of concern for the security and trust of many applications, such as multi-tenant and multi-level security single FPGA designs. Previous works utilized a sensor co-located on the same FPGA with a target module which was able to detect side channel voltage variations. We build on this by creating a sensor with more programmability and sensitivity resulting in improved recovery of bit patterns from an isolated target. We demonstrate for the first time the recovery of an unknown target frequency and data pattern length in a multi-user FPGA side channel attack. We also show increased sensitivity over previously developed voltage sensors enabling data recovery with fewer samples.