Mobile Communications & Networking
5G Cellular Networks
Our current research considers a range of topics in the domain of 5G Cellular Networks within the RAN and the EPC. In developing technologies for deploying massive MIMO systems, we are exploiting the systems' decorrelation property to avoid unnecessary pre-coder computations, thereby reducing scheduler overhead. In our work with millimeter wave technologies, we are developing solutions using beam tracking technology that do not require explicit channel measurement. We are also creating a novel design framework for MU-MIMO scheduling in millimeter-wave networks that considers hybrid beamforming (analog plus digital precoding) at the transmitter and receiver nodes. We use transmit and receive analog precoding to reduce the CSI feedback overhead. Dual connectivity (DC) is a feature that targets emerging practical HetNet deployments that will consist of non-ideal (higher latency) connections between transmission nodes. It has been recently introduced to the LTE-Advanced standard. DC allows for a user to be simultaneously served by a macro node as well as one other (typically micro or pico) node and requires coarser level coordination among serving nodes. For such a DC-enabled HetNet, we comprehensively analyze the problem of determining an optimal user association and then develop efficient solutions.
First responders, a critical lifeline of any society, often find themselves in precarious situations. The ability to track them real-time in unknown indoor environments, significantly contributes to the success of their mission as well as their safety. In this work, we present the design, implementation and evaluation of TrackIO – a novel system that is capable of accurately localizing and tracking mobile responders real-time in large indoor environments. NavigateIO leverages the ultra wide-band (UWB) technology, fusing it with inertial sensors to accomplish this objective directly from outside, without relying on access to any indoor infrastructure. Towards a practical system, NavigateIO incorporates four novel mechanisms in its design that address key challenges to enable tracking responders: (i) who are mobile with potentially non-uniform velocities (e.g. during turns), NavigateIO’s real-world performance reveals that it can track static nodes with a median accuracy of about 1–1.5 m and mobile nodes with a median accuracy of 1.5-2m.
End-to-End Solutions Using Wireless Sensing & Communications
In this area of research, we focus on developing solutions for different industry domains based on multimodal sensing and communication technologies, with wireless playing the major role. In the retail world, we have been developing a suite of technologies to be deployed in the storefront to both enable a better customer shopping experience and provide valuable data to the retailer. Our Virtual Shielding technology provides a seamless checkout solution using RFID, which is more cost effective for the retailer and less cumbersome to use for the customer compared to existing solutions. A second RFID-based technology provides a generalized, battery-free, touch-and-gesture-sensing user interface (UI) primitive applicable in retail environments.
Radar Array Research
Wireless sensing and localization utilizes pervasive RF energy to detect and understand activities in the physical environment, unencumbered by obstructions, lighting, smoke, dust, rain or other interference sources that plague alternative sensing technologies. To that end, our research focuses on two key pillars of wireless sensing: Cooperative radar sensing, and radar array design. Cooperative radar sensing utilizes new techniques to automatically synchronize radar signals from small, widely dispersed, radar units to enable coordinated sensing across a wide region at low cost, and low overhead. Such techniques are important given the rapid availability of low-cost RF sensors that are embedded into everyday smart devices, such as TVs, smart speakers, cellphones, and smart watches. Radar array research focuses on the development of centrally managed, tightly coordinated radar platforms that can be seamlessly embedded into existing physical environments, so that every-day places can be quickly turned into truly digitized environments.