CRII: CNS: Towards Spectrum and Energy Efficient Large-scale IoT Communications: A Cross-layer Optimization Approach

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Although 5G has dramatically improved network capacity and spectrum efficiency (SE), the explosive growth of Internet of Things (IoT) demands for more spectrum and energy resources to support high device density and massive traffics. It is estimated that at least 5.2 GHz bandwidth is required for just eHealth Care IoT if spectrum is accessed exclusively, or 1.3 GHz even with dynamic sharing strategy. It is clear that shortage of spectrum resources is a major bottleneck for the success of IoT popularity. On the other hand, current IoT devices use standards such as Bluetooth, LoRA, Sigfox, narrow-band IoT (NB-IoT), or Zigbee, which require power-hungry active radio frequency components like oscillators and converters. Battery-driven IoT devices can hardly sustain years of life-cycle goal even with infrequent transmission and optimized low-power protocols. Thus, sustainable energy consumption is another challenge. With tens of billions of IoTs desire for connectivity by 2030, there is a pressing need to address both SE and energy efficiency (EE) challenges to accommodate for such densified IoT networks. This research seeks to improve SE and EE performance while providing guaranteed quality of service (QoS) for IoTs at large-scale, thereby providing a feasible and practical connectivity solution in massive IoT era. Outcomes from this project can bring following impacts: 1) a hybrid and cooperative communication architect for IoTs, which combines benefits from both active and passive mode; 2) integration of research and curriculum design, capstone projects to both undergraduate and graduate students; 3) cutting-edge research experiences to a primarily undergraduate institution (PUI). The core approach is to enable IoT device with a wireless-powered hybrid communication structure that can not only minimize energy footprint with energy harvesting from ambient signals, but also integrate coordinated passive and active communication to support versatile QoS needs with efficient spectrum utilization through user cooperation. This project offers a holistic solution to deliver following innovations. 1) A novel PHY transmission architect. It combines a bio-inspired symbiotic radio to coordinate excessive interference. Optimization problems for SE and EE metrics are introduced from PHY resource allocation perspective. 2) The co-designed MAC layer protocol to ensure proper user and resource coordination. Two protocols will be introduced, one for maximum performance and the other for lower complexity. 3) System validation with software and hardware implementations. Extensive experimental verification is designed to systematically validate the performance of proposed schemes and algorithms. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.