Rate Maximization for Multi-Waveguide PASS: A Hierarchical User Scheduling and Joint Optimization Framework
摘要
Pinching-antenna systems (PASS) have emerged as a promising flexible-antenna architecture capable of dynamically reconfiguring wireless channels by activating dielectric particles along waveguides. The sum rate maximization problem in multi-waveguide PASS is investigated in this study. Both in-waveguide propagation loss and coupling effects are explicitly modeled. To tackle the optimization problem, a hierarchical user scheduling (HUS) algorithm is proposed. The HUS algorithm minimizes the sum of squared distances between users and their associated waveguides to mitigate path loss. Additionally, spatially separated users are assigned within each time slot to reduce inter-user interference. Furthermore, a joint optimization framework integrating power allocation and pinching-antenna (PA) positioning is developed to further improve system sum rate. Specifically, PAs' positions are optimized via one-dimensional search, while the power allocation problem is solved by using the Lagrangian duality and fractional programming. Numerical results show that the HUS algorithm clearly outperforms random pairing, and the proposed power allocation algorithm shows a marked performance improvement over the maximum ratio transmission algorithm. Moreover, the results explicitly demonstrate the considerable impact of in-waveguide propagation loss and coupling effects on the performance of PASS.
相关性判断
highPaper is in cs.IT and addresses wireless communication system design: sum-rate maximization, user scheduling, power allocation, and channel/hardware modeling for multi-waveguide PASS, which is directly adjacent to communications and information theory.
High relevance to cs.IT wireless communications with explicit PASS physical modeling, scheduling, power allocation, and PA positioning. Structure analysis indicates concrete technical machinery and validated numerical gains over random pairing and MRT baselines. Novelty appears mainly in integrating multi-waveguide PASS loss/coupling modeling with hierarchical scheduling and joint optimization rather than a fundamentally new optimization theory.
核心问题与主要方法
核心问题
Maximize sum rate in multi-waveguide PASS under physical loss/coupling effects, user scheduling, and minimum-rate constraints
场景：Downlink multi-waveguide pinching-antenna system with TDMA, multiple users, sequential PAs on each waveguide, and explicit propagation-loss/coupling modeling
主要方法
Unified PASS hardware model combines dissipative waveguide propagation with a coupled-mode model for waveguide-to-PA energy transfer, including residual field propagation across sequential PAs. Hierarchical scheduling first solves a relaxed waveguide-user pairing problem using distance-to-waveguide metrics, then applies an SCA-style in-slot selection surrogate to separate co-scheduled users spatially. PA locations are updated one at a time using Gauss-Seidel-style one-dimensional grid search over feasible sequential placement intervals. Power allocation is reformulated through Lagrangian duality and fractional programming, then solved iteratively with locally tight first-order convex approximations.
关键贡献与后续阅读
关键贡献
Formulates a multi-waveguide PASS sum-rate maximization problem that includes propagation loss, waveguide-PA coupling, inter-waveguide interference, PA placement constraints, scheduling variables, power allocation, and minimum-rate constraints. Introduces a physics-aware hardware/signal model where lossy waveguide propagation affects amplitude and phase, and coupled-mode theory determines PA coupling and residual field behavior along sequential PAs. Proposes HUS to combine geometry-driven waveguide-user pairing with spatially separated in-slot scheduling for path-loss and interference mitigation. Develops an AO optimization pipeline combining one-dimensional PA-position search with Lagrangian-duality/fractional-programming/SCA power allocation. Provides numerical evidence that loss and coupling materially affect PASS performance, and that optimized scheduling/resource allocation can outperform random pairing and MRT baselines.
研究启发
How strong are the random pairing and MRT baselines relative to current PASS-specific scheduling or beamforming baselines? Are the reported gains sensitive to the assumed PTFE material parameters, dielectric loss tangent, and G=10000 grid resolution? Does the framework remain tractable when K is not an exact multiple of M, users are mobile, or waveguides coordinate beyond the TDMA structure? Are code, solver settings, and Monte Carlo seeds available for reproducing the numerical claims?
限制与不确定性
Evidence is based on abstract and structure analysis only; numerical setup, baseline strength, and reproducibility are not independently checked. Optimization is heuristic or locally optimal in key parts, including discretized PA placement and KKT-level power allocation.
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