Connecting the Unconnectable through Feedback
Yimeng Li, Yulin Shao
TL;DR
IoT devices at cell edges face uplink reliability challenges due to limited power and single-antenna hardware. The paper proposes a feedback-aided uplink framework that leverages real-time AP decoding feedback and feedback channel codes to induce dual-channel coupling, effectively lowering the uplink SNR requirement to a logistic threshold $\Omega_f$ and expanding connectable APs without increasing device power. An analytical model based on Gauss-Laguerre quadrature yields tractable expressions for the connectable probability $\varphi_f(R)$ and the average number of connectable APs $M_f(D)$, contrasted against forward-mode benchmarks with $\varphi_c(R)$ and $M_c(D)$. Numerical results show up to 51% more connectable APs and a 24% range extension at the cell edge, validating the approach and highlighting trade-offs in downlink bandwidth and latency due to feedback. The work demonstrates a robust, energy-efficient pathway to connect the unconnectable IoT devices in challenging environments, with practical applicability to modern edge networks.
Abstract
Reliable uplink connectivity remains a persistent challenge for IoT devices, particularly those at the cell edge, due to their limited transmit power and single-antenna configurations. This paper introduces a novel framework aimed at connecting the unconnectable, leveraging real-time feedback from access points (APs) to enhance uplink coverage without increasing the energy consumption of IoT devices. At the core of this approach are feedback channel codes, which enable IoT devices to dynamically adapt their transmission strategies based on AP decoding feedback, thereby reducing the critical uplink SNR required for successful communication. Analytical models are developed to quantify the coverage probability and the number of connectable APs, providing a comprehensive understanding of the system's performance. Numerical results validate the proposed method, demonstrating substantial improvements in coverage range and connectivity, particularly for devices at the cell edge, with up to a 51% boost in connectable APs. Our approach offers a robust and energy-efficient solution to overcoming uplink coverage limitations, enabling IoT networks to connect devices in challenging environments.
