arXiv subjects

Yayun Qu

Publications and source records attributed to Yayun Qu.

2 recordsLinked to original sources

arXiv2026

Curved Waveguide-Enabled Pinching-Antenna System (C-PAS): Communication Performance Analysis

Existing studies on the pinching-antenna system (PAS) assume that waveguides are deployed straight, which fails to serve communication regions with curved boundaries. To address this limitation, this paper proposes a curved waveguide-enabled pinching-antenna system (C-PAS), where the waveguide is placed along the building ceiling in an arc to maximize the line-of-sight (LoS) coverage. On this basis, the optimal pinching-antenna (PA) placement strategy and the nearest PA placement strategy are presented. The optimal strategy distinguishes between scenarios, i.e., with or without inner-wall blockage, and derives a closed-form solution for the optimal PA position to maximize the signal-to-noise ratio (SNR) received at the user. Meanwhile, the nearest strategy aligns the PA with the angular position of a user in polar coordinates, thereby accommodating the curved geometry of the region. Furthermore, the outage probability (OP) and the average rate (AR) are analyzed for each strategy, and the corresponding analytical expressions are derived, respectively. The results show that the optimal PA placement strategy achieves better OP and AR performance than the nearest strategy, particularly under large waveguide loss coefficient or waveguide height. Moreover, for a service region of fixed area, there exists an optimal sector angle or inner-wall radius that either minimizes the outage probability or maximizes the average rate. Furthermore, the choice of a waveguide bending radius is influenced by the transmit power of the base station, where a smaller bending radius is preferable at high power and the middle arc performs best at low power.

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arXiv2026

Vertical Pinching Antenna Systems (V-PAS) Aided UAV Communications

To address the limitation that existing horizontal pinching antenna systems (PAS) are primarily designed for ground users and confined to two-dimensional (2D) coverage, this paper proposes deploying a pinching antenna (PA) along the facade of urban buildings to construct a vertical pinching antenna system (V-PAS) for ultra-low-altitude unmanned aerial vehicle (UAV) communications. The proposed architecture employs a dielectric waveguide continuously deployed along the full height of buildings, extending the coverage capability of PAS from the 2D plane to three-dimensional (3D) airspace, ensuring a stable line-of-sight (LoS) link. We define the concept of pinching multiplicative path loss (PMPL) to characterize the cascaded multiplicative attenuation of the waveguide and free-space path losses. It is found that PMPL is insensitive to vertical distance, rendering V-PAS highly adaptive to building heights. Furthermore, accurate and asymptotic closed-form expressions for outage probability and ergodic rate under lossy waveguide conditions are derived, respectively, and the symmetry and optimality of system performance with respect to the midpoint of the access point (AP) height are discovered and proved. The results show that V-PAS achieves performance advantages over the benchmark without PA in most ultra-low-altitude UAV communication scenarios. Only under extremely high transmission power and large UAV operational area may the outage probability of V-PAS with a lossy waveguide be inferior to that of the benchmark without PA, but the ergodic rate of V-PAS still maintains an advantage. By contrast, V-PAS with a lossless waveguide outperforms the benchmark without PA in UAV communications, representing the theoretical performance upper bound of V-PAS.

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