Impact of Antenna Position Errors on TDMA and NOMA in Pinching-Antenna Systems

2026-09-25

AI Summary

This study addresses the phase deviations and performance degradation caused by mechanical positioning errors in clamp-mounted antenna systems. By establishing a positioning error model and analyzing its impact on TDMA and NOMA systems, the work integrates wireless channel modeling, stochastic geometry analysis, and closed-form mathematical derivations to obtain exact expressions for ergodic rate bounds and outage probabilities. This research provides the first quantification of how non-ideal antenna placement specifically affects multiple access schemes. It reveals that single-antenna TDMA exhibits inherent robustness against positioning errors, whereas NOMA suffers from an irreducible interference floor. These findings offer a rigorous theoretical foundation for selecting appropriate multiple access strategies in practical antenna system deployments.

Abstract

Pinching-antenna systems (PASS) create reconfigurable wireless channels by moving dielectric antennas along a waveguide. Mechanical position errors translate into phase errors that degrade performance, yet almost all prior PASS studies assume ideal placement. This paper models this position error, derives the resulting phase error, and analyzes its impact on time-division multiple access (TDMA) and non-orthogonal multiple access (NOMA), obtaining their ergodic-rate bounds and closed-form outage probabilities. Analyses and simulations reveal that single-antenna TDMA is immune to position error, whereas multi-antenna TDMA loses array gain and NOMA suffers an interference floor that cannot be overcome by increasing transmit power.

Problem

• Pinching-antenna systems
• Position errors
• Phase errors
• TDMA
• NOMA

Innovation

• Pinching-Antenna Systems
• Position Error Modeling
• Phase Error Derivation
• TDMA and NOMA Analysis
• Closed-Form Outage Probability