Body Sensor Networks: A Holistic Approach from Silicon to Users

Abstract:

Body sensor networks (BSN) are emerging cyber-physical systems that promise to improve the quality of life through improved health, augmented sensing and actuation for the disabled, independent living for the elderly, and reduced healthcare costs. However, the physical nature of BSNs introduces several new challenges. The human body, especially in the context of medical conditions, is a highly dynamic and unpredictable physical environment that creates constantly changing demands on sensing, actuation, and quality of service (QoS). At the same time, movement between indoor and outdoor environments and rapid physical movements of arms and legs 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. This work employs a clean slate approach, designing and implementing all the hardware and software from the ground up. Microcontrollers, accelerators, and radios have been created with low power designs in 130nm CMOS and implemented with a SOC. A QoS framework has been developed to support coordination within and across multiple BSNs. Several new applications have been developed to exercise a multi-function BSN. This includes fall detection and social interaction. Application driven optimizations based on a quality of information metric have also been developed.