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Resolving the Double Near-Far Problem via Wireless Powered Pinching-Antenna Networks

Vasilis K. Papanikolaou, Gui Zhou, Brikena Kaziu, Ata Khalili, Panagiotis D. Diamantoulakis, George K. Karagiannidis, Robert Schober

TL;DR

The paper tackles the double near-far problem in wireless powered networks by proposing wireless powered pinching-antenna networks (WPPAN), where a base station provides energy via a single waveguide with movable pinching antennas that serve nearby users more effectively for both downlink energy harvesting and uplink data transmission. It develops a harvest-then-transmit TDMA protocol and formulates a max-min rate optimization over antenna activations and time allocations, introducing three complexity-controlling approaches: an exhaustive search (up to combinatorial scale), a greedy method, and a naive one-hot activation scheme. The authors demonstrate, through a nonlinear energy-harvesting model and extensive simulations, that WPPAN significantly improves the minimum user rate compared to a conventional multi-antenna baseline, with the greedy method achieving near-optimal performance and robust gains as the network scales. The work highlights the practical potential of distributed pinching antennas along a waveguide to shape channels and near-term convex-optimization techniques to manage the resulting combinatorial design space, indicating meaningful gains for energy harvesting efficiency and uplink throughput in future wireless networks.

Abstract

This letter introduces a novel wireless powered communication system, referred to as a wireless powered pinching-antenna network (WPPAN), utilizing a single waveguide with pinching antennas to address the double near-far problem inherent in wireless powered networks. In the proposed WPPAN, users harvest energy from spatially distributed pinching antennas in the downlink and use the collected power to transmit messages in the uplink. Furthermore, to manage the combinatorial complexity associated with activating the pinching antennas, we propose three approaches of varying complexity to simplify the original resource allocation problem and then solve it efficiently using convex optimization methods. Simulation results confirm that the proposed WPPAN system effectively mitigates the double near-far problem by providing antenna resources closer to the users, thereby enhancing both downlink energy harvesting and uplink data transmission.

Resolving the Double Near-Far Problem via Wireless Powered Pinching-Antenna Networks

TL;DR

The paper tackles the double near-far problem in wireless powered networks by proposing wireless powered pinching-antenna networks (WPPAN), where a base station provides energy via a single waveguide with movable pinching antennas that serve nearby users more effectively for both downlink energy harvesting and uplink data transmission. It develops a harvest-then-transmit TDMA protocol and formulates a max-min rate optimization over antenna activations and time allocations, introducing three complexity-controlling approaches: an exhaustive search (up to combinatorial scale), a greedy method, and a naive one-hot activation scheme. The authors demonstrate, through a nonlinear energy-harvesting model and extensive simulations, that WPPAN significantly improves the minimum user rate compared to a conventional multi-antenna baseline, with the greedy method achieving near-optimal performance and robust gains as the network scales. The work highlights the practical potential of distributed pinching antennas along a waveguide to shape channels and near-term convex-optimization techniques to manage the resulting combinatorial design space, indicating meaningful gains for energy harvesting efficiency and uplink throughput in future wireless networks.

Abstract

This letter introduces a novel wireless powered communication system, referred to as a wireless powered pinching-antenna network (WPPAN), utilizing a single waveguide with pinching antennas to address the double near-far problem inherent in wireless powered networks. In the proposed WPPAN, users harvest energy from spatially distributed pinching antennas in the downlink and use the collected power to transmit messages in the uplink. Furthermore, to manage the combinatorial complexity associated with activating the pinching antennas, we propose three approaches of varying complexity to simplify the original resource allocation problem and then solve it efficiently using convex optimization methods. Simulation results confirm that the proposed WPPAN system effectively mitigates the double near-far problem by providing antenna resources closer to the users, thereby enhancing both downlink energy harvesting and uplink data transmission.
Paper Structure (16 sections, 1 theorem, 15 equations, 3 figures, 1 algorithm)

This paper contains 16 sections, 1 theorem, 15 equations, 3 figures, 1 algorithm.

Table of Contents

  1. Introduction
  2. System Model
  3. Pinching-Antenna System
  4. Network Protocol
  5. Non-Linear Energy Harvesting Model
  6. Wireless Powered Pinching-Antenna Networks
  7. Antenna Activation
  8. Energy Harvesting
  9. Information Transmission
  10. Minimum Rate Maximization
  11. Search-based WPPAN
  12. Greedy WPPAN
  13. Naive WPPAN
  14. Numerical Results
  15. Conclusions
  16. ...and 1 more sections

Key Result

Lemma 1

For fixed $\mathbf{b}_u$, given by eq:optimaluplink, and $\mathcal{Q} = \mathcal{S}$, opt TS3 is reduced to a convex optimization problem in $\boldsymbol{\tau}_d$ and $\boldsymbol{\tau}_u$ and can therefore be solved optimally in polynomial time with interior-point methods.

Figures (3)

  • Figure 1: Maximum minimum rate versus transmit power.
  • Figure 2: Maximum minimum rate versus number of users.
  • Figure 3: Sampled probability density distribution of optimal number active pinching antennas for $N=10$, $M=5$.

Theorems & Definitions (1)

  • Lemma 1