Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

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

Zijian Yang, Yulin Shao, Shaodan Ma

TL;DR

FACET addresses energy-constrained IoT by coupling adaptive feedback channel coding with wireless power transfer. It introduces a two-stage optimization (Hungarian subcarrier assignment followed by convex power/power-splitting optimization) and a closed-form dual-decomposition solution that yields a dual-purpose downlink: improved uplink reliability and device energy harvesting. The approach achieves a near-optimal tradeoff between coding gains and harvested energy under a fairness constraint, enabling substantial lifetime extensions across power regimes. Practically, FACET redefines feedback in IoT as a resource that both enhances communication efficiency and replenishes energy, supporting greener, longer-lived networks.

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.

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

TL;DR

FACET addresses energy-constrained IoT by coupling adaptive feedback channel coding with wireless power transfer. It introduces a two-stage optimization (Hungarian subcarrier assignment followed by convex power/power-splitting optimization) and a closed-form dual-decomposition solution that yields a dual-purpose downlink: improved uplink reliability and device energy harvesting. The approach achieves a near-optimal tradeoff between coding gains and harvested energy under a fairness constraint, enabling substantial lifetime extensions across power regimes. Practically, FACET redefines feedback in IoT as a resource that both enhances communication efficiency and replenishes energy, supporting greener, longer-lived networks.

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.

Paper Structure

This paper contains 11 sections, 14 equations, 4 figures, 1 table.

Table of Contents

  1. Introduction
  2. System Model
  3. Feedback-Aided Coding and Energy Transfer
  4. The Fundamental Tradeoff of FACET
  5. Solving the Fundamental Tradeoff
  6. Closed-Form Solution via Lagrangian Duality
  7. Solutions for the auxiliary variables
  8. Solutions for power allocation and power splitting ratios
  9. Dual variable updates via subgradient method
  10. Performance Evaluation and Discussion
  11. Conclusion

Figures (4)

  • Figure 1: System model and frame structure of the feedback-aided IoT uplink, where uplink transmission and downlink feedback alternate in time for real-time adaptive coding.
  • Figure 2:
  • Figure 3:
  • Figure 4: