Antenna position errors reduce performance in multi-antenna wireless systems
Impact of Antenna Position Errors on TDMA and NOMA in Pinching-Antenna Systems
Information Theory
Summary
Wireless systems that move antennas along a waveguide try to create better signals. But small mistakes in antenna placement cause signal problems. The authors show that some systems with one antenna handle these mistakes well, while systems with more antennas or using advanced sharing methods do worse. These problems limit how well the wireless system works, even if you increase signal power.
What this means in practice
- •For wireless network engineers: Identify when antenna positioning errors will degrade multi-antenna TDMA or NOMA system performance in waveguide-based designs.
- •For hardware designers for phased arrays: Design antenna movement mechanisms with precision tolerances that avoid phase errors impacting multi-antenna wireless channel reconfiguration.
Authors
Wei Jiang, Hans D. Schotten
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.