Adaptive Transmission Scheduling for Energy-Aware Real-Time Wireless Communication.

Real-time low-power wireless networks are increasingly being used in applications such as: Industrial Internet-of-Things, Smart City technologies, and critical infrastructure monitoring. These networks typically use time-slotted super-frame techniques to ensure real-time performance. Often the time slots are assigned statically, and energy conservation is regulated to other mechanisms such as duty cycling. This paper combines real-time performance with novel energy conservation methods by describing a set of dynamic modulation based adaptive packet transmission scheduling algorithms that are designed to reclaim unused slot times. Our approach uses hybrid link access mechanisms. To support our reclaiming method in a wireless environment we introduce a novel low-power listening technique called reverse-low-power listening (RLPL) as part of an overall Hybrid Low-Power Listening (HLPL) protocol. We evaluate our algorithms against an oracle-based approach, and show that our dynamic slot reclaiming approach, coupled with HLPL, can introduce substantial power savings without sacrificing real-time support.