Recent work has shown that monolithic integration of voltage regulators will be feasible in the near future, enabling reduced system cost and the potential for fine-grain voltage scaling (FGVS). More specifically, on-chip switched-capacitor regulators appear to offer an attractive trade-off in terms of integration complexity, power density, power efficiency, and response time. In this paper, we use architecture-level modeling to explore a new dynamic voltage/frequency scaling controller called the fine-grain synchronization controller (FG-SYNC+). FG-SYNC+ enables improved performance and energy efficiency at similar average power for multithreaded applications with activity imbalance. We then use circuit-level modeling to explore various approaches to organizing on-chip voltage regulation, including a new approach called reconfigurable power distribution networks (RPDNs). RPDNs allow one regulator to "borrow" energy storage from regulators associated with underutilized cores resulting in improved area/power efficiency and faster response times. We evaluate FG-SYNC+ and RPDN using a vertically integrated research methodology, and our results demonstrate a 10-50% performance and 10-70% energy-efficiency improvement on the majority of the applications studied compared to no FGVS, yet RPDN uses 40% less area compared to a more traditional per-core regulation scheme.

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Bluetooth Low Energy (BLE) mesh networks enable diverse communication for the Internet of Things (IoT). However, existing BLE mesh implementations cannot simultaneously achieve low-power operation, symmetrical communication, and scalability. A major limitation of mesh networks is the inability of the BLE stack to handle network-scalable time synchronization. Pulse-coupled oscillators (PCOs) have been studied extensively and are able to achieve fast and reliable synchronization across a range of applications and network topologies. This paper presents a lightweight physical (PHY) layer accelerator to the BLE stack that enables scalable synchronization command with a PCO. The accelerator is a fully digital solution that can be synthesized with only the standard cells available in any silicon technology. This paper provides a detailed analysis of PCO-based BLE mesh networks and explores per-node system-level requirements. Finally, the analytical results are validated with measurements of a custom radio node based on the ubiquitous AD9364 transceiver.