Multiple Access Design and Resource Allocation in Pinching-Antenna Systems

Abstract

Multiple access (MA) design is investigated to facilitate pinching-antenna systems (PASS)-based multi-user communications. By exploiting the newly introduced waveguide domain and existing frequency domain, two MA schemes are explored, namely pure waveguide division multiple access (WDMA) and hybrid WDMA. For each MA scheme, the corresponding resource allocation problem is formulated to maximize the rate fairness via the joint optimization of pinching beamforming and power allocation. For both schemes, a majorization-minimization (MM)-based alternating optimization (AO) algorithm is proposed that alternately optimizes pinching beamforming and transmit power. A low-complexity framework is further developed, including a two-stage pinching beamforming design and successive convex approximation (SCA)-based power allocation. Numerical results demonstrate that: 1) PASS significantly improve communication rate performance over conventional antenna systems; 2) The proposed MM-based AO algorithm provides higher performance at the cost of increased complexity, while the low-complexity framework achieves comparable performance with lower computational complexity; and 3) Pure WDMA achieves better performance compared to hybrid WDMA, efficiently supporting multi-user communications enabled by pinching beamforming.