The objective of this research is to develop new principles and techniques for adaptive operation in highly dynamic physical environments, using miniaturized, energy-constrained devices. The approach is to use holistic cross-layer solutions that simultaneously address all aspects of the system, from low-level hardware design to higher-level communication and data fusion algorithms to top-level applications. In particular, this work focuses on body area sensor networks as emerging cyber-physical systems. The intellectual merit includes producing new principles regarding how cyber systems must be designed in order to continually adapt and respond to rapidly changing physical environments, sensed data, and application contexts in an energy-efficient manner. New cross-layer technologies will be created that use a holistic bottom-up and top-down design -- from silicon to user and back again. A novel system-on-a-chip hardware platform will be designed and fabricated using three cutting-edge technologies to reduce the cost of communication and computation by several orders of magnitude. The broad impact of this project will enable the wide range of applications and societal benefits promised by body area networks, including improving the quality and reducing the costs of healthcare. The technology will have broad implications for any cyber physical system that uses energy constrained wireless devices. A new seminar series will bring together experts from many fields (including domain experts, such as physicians and healthcare professionals). The key aspects of this work that deal with healthcare have the potential to attract women and minorities to the computer field.
Body sensor networks (BSN) are emerging cyber-physical systems that promise to improve quality of life through improved healthcare, augmented sensing and actuation for the disabled, independent living for the elderly, and reduced healthcare costs. However, the physical nature of BSNs introduces new challenges. The human body is a highly dynamic physical environment that creates constantly changing demands on sensing, actuation, and quality of service. Movement between indoor and outdoor environments and physical movements constantly change the wireless channel characteristics. These dynamic application contexts can also have a dramatic impact on data and resource prioritization. Thus, BSNs must simultaneously deal with rapid changes to both top-down application requirements and bottom-up resource availability. This is made all the more challenging by the wearable nature of BSN devices, which necessitates a vanishingly small size and, therefore, extremely limited hardware resources and power budget. Our proposed research includes developing new principles and techniques for adaptive operation in highly dynamic physical environments, using miniaturized, energy-constrained devices. The approach uses a holistic cross-layer design that addresses all aspects of the system, from low-level hardware design to higher-level communication and data fusion algorithms, to top-level applications. In this second year we have made progress in the following: applications, channel and interference modeling, design principles, MAC design, energy harvesting, energy models, and QoS design and tradeoffs. We demonstrated a stand-alone wakeup radio designed for highly dynamic wireless channels in a BSN, as well as custom hardware for characterizing dynamic wireless channels around a body. We also integrated this wakeup radio, along with two communication radios and an RF energy harvesting front-end into a complete system-on-chip (SoC) for BSN applications. The SoC design was a collaboration with the other PIs on this grant at the Univ. of Virginia. Along with these radios, the SoC includes power management to harvest energy from a TEG or solar cell, an analog front-end for EKG measurements, a microcontroller, memory, and hardware accelerators for extracting information such as arrhythmia and heart rate from the EKG data.
