When Feedback Empowers the Uplink: Integrating Adaptive Coding with Wireless Power Transfer

TL;DR

This paper presents FACET, a framework that combines adaptive feedback coding with wireless power transfer to significantly extend IoT device lifetime by optimizing energy and communication tradeoffs.

Contribution

Introducing a novel feedback mechanism that jointly enhances uplink coding and energy harvesting, optimizing IoT device longevity under power constraints.

Findings

Nearly triples device lifetime compared to traditional methods

Robust performance across various power regimes

Efficient algorithm with closed-form solutions for optimization

Abstract

Energy consumption and device lifetime are critical concerns for battery-constrained IoT devices. This paper introduces the Feedback-Aided Coding and Energy Transfer (FACET) framework, which synergistically combines adaptive feedback channel coding with wireless power transfer. FACET leverages the saturation effect of feedback coding, where increasing downlink power yields diminishing returns, to design a dual-purpose feedback mechanism that simultaneously guides uplink coding and replenishes device energy. We characterize the inherent tradeoff between feedback precision and harvested power, and formulate a fairness-constrained min-max optimization problem to minimize worst-case net energy consumption. An efficient algorithm based on alternating optimization and Lagrangian duality is developed, with each subproblem admitting a closed-form solution. Simulations show that FACET nearly triples device lifetime compared to conventional feedback coding architectures, and remains robust across a wide range of power regimes. These results suggest that FACET not only improves communication efficiency but also redefines the role of feedback in energy-constrained IoT systems.