Abstract
Future Internet of Things (IoT) applications demand highly energy-efficient wireless transmission solutions. In this article, we characterize the energy efficiency (EE) of wireless transmission over fading channels from individual transmission session perspective. Specifically, we apply a statistical EE metric to analyze and optimize ideal continuous rate adaptation (CRA) and continuous power adaptation (CPA) transmission schemes. The resulting statistical characterization establishes an EE performance limit for data transmissions over fading channels and facilitates a direct tradeoff analysis between maximal achievable EE and instantaneous latency requirement.