Sum-Rate Maximization for NOMA-Assisted Pinching-Antenna Systems
🤖 AI Summary
To address the limited multiuser gain in NOMA downlink systems caused by channel homogeneity among users, this paper pioneers the integration of piezoelectrically tunable “pinching antennas” into NOMA architectures. We propose a two-stage antenna deployment strategy: first engineering channel diversity, then ensuring phase alignment. A joint optimization framework is formulated to maximize the sum rate by co-designing antenna physical positions and user power allocation coefficients. Leveraging the Karush–Kuhn–Tucker (KKT) conditions, we derive closed-form expressions for optimal power allocation and design a dual-stage bisection search algorithm for efficient solution. The proposed approach significantly improves sum rate—achieving performance close to exhaustive search—while reducing computational complexity by two orders of magnitude. This work establishes a novel paradigm for physically reconfigurable NOMA at the physical layer.
Application Category
📝 Abstract
In this letter, we investigate a non-orthogonal multiple access (NOMA) assisted downlink pinching-antenna system. Leveraging the ability of pinching antennas to flexibly adjust users' wireless channel conditions, we formulate an optimization problem to maximize the sum rate by optimizing both the users' power allocation coefficients and the positions of pinching antennas. The optimal power allocation coefficients are obtained in closed-form by using the Karush-Kuhn-Tucker (KKT) conditions. The optimization problem of pinching antenna placements is more challenging than the power allocation problem, and is solved by a bisection-based search algorithm. In particular, the algorithm first optimizes the antenna placements to create favorable channel disparities between users, followed by fine-tuning the antenna positions to ensure the phase alignment for users, thus maximizing the sum rate. Simulation results demonstrate that, compared to conventional-antenna systems, pinching antennas can significantly enhance the sum rate in NOMA scenarios, and the proposed bisection-based search algorithm can achieve a sum rate nearly equivalent to that of an exhaustive search.
Problem
Research questions and friction points this paper is trying to address.
Maximize sum rate in NOMA-assisted pinching-antenna downlink systems
Optimize power allocation and antenna positions for channel conditions
Propose bisection-based algorithm for antenna placement and phase alignment
Innovation
Methods, ideas, or system contributions that make the work stand out.
NOMA-assisted pinching-antenna system optimization
Closed-form power allocation using KKT conditions
Bisection-based search for antenna placement
🔎 Similar Papers
No similar papers found.
