Environment-Aware Network-Level Design of Generalized Pinching-Antenna Systems--Part II: Geometry-Aware Case

This two-part paper aims to develop an environment-aware network-level design framework for generalized pinching-antenna systems to overcome the limitations of conventional link-level optimization, which is tightly coupled to instantaneous user geometry and thus sensitive to user mobility and localization errors. Part I investigates the traffic-aware case, where user presence is characterized statistically by a spatial traffic map and deployments are optimized using traffic-aware network-level metrics. Part II complements Part I by developing geometry-aware, blockage-aware network optimization for pinching-antenna systems in obstacle-rich environments. We introduce a grid-level average signal-to-noise (SNR) model with a deterministic LoS visibility indicator and a discrete activation architecture, where the geometry-dependent terms are computed offline in advance. Building on this model, we formulate two network-level activation problems: (i) average-SNR-threshold coverage maximization and (ii) fairness-oriented worst-grid average-SNR maximization. On the algorithmic side, we prove the coverage problem is NP-hard and derive an equivalent mix-integer linear programming reformulation through binary coverage variables and linear SNR linking constraints. To achieve scalability, we further develop a structure-exploiting coordinate-ascent method that updates one waveguide at a time using precomputed per-candidate SNR contributions. For the worst-grid objective, we adopt an epigraph reformulation and leverage the resulting monotone feasibility in the target SNR, enabling an efficient bisection-based solver with low-complexity feasibility checks over the discrete candidate set. Simulations results validate the proposed designs and quantify their gains under different environments and system parameters.

💡 Research Summary

This paper addresses the challenge of providing uniform wireless service in environments densely populated with obstacles (e.g., indoor partitions, urban canyons) by exploiting the spatial reconfigurability of generalized pinching‑antenna systems. Unlike conventional fixed‑site base stations whose radiation points are immutable, a pinching antenna can radiate from any selected point along a dielectric waveguide, effectively moving the transmit/receive location within the service area. The authors propose a network‑level design framework that leverages pre‑known blockage geometry, thereby eliminating the need for instantaneous user location or channel state information.

System Model
The service region is a rectangular area discretized into a fine 2‑D grid (Nₕ × Nᵥ cells). K rectangular cuboid blockages are specified in three‑dimensional coordinates, defining deterministic line‑of‑sight (LOS) visibility for any potential antenna‑grid pair. N dielectric waveguides run parallel to the x‑axis under the ceiling; each waveguide hosts M pre‑defined candidate pinching‑antenna positions. A binary activation matrix A∈{0,1}^{N×M} selects exactly one candidate per waveguide (∑ₘ aₙ,ₘ = 1 ∀ n). Because the set of candidates is finite, the control signal reduces to a low‑rate index per waveguide, which is practical for real deployments.

Geometry‑Aware Channel Model
For each grid cell (u,v) and each candidate (n,m), the LOS indicator 𝟙{LOSₙ,ₘ(u,v)} is computed offline by checking whether the straight line between the candidate and the grid point intersects any blockage. Combined with distance‑based path loss, waveguide attenuation, and a deterministic NLoS fading factor, a per‑candidate gain gₙ,ₘ(u,v) is pre‑computed. The average SNR experienced at grid (u,v) becomes a linear function of the activation variables: \