Impact of Out-of-Band Emissions From Active Antenna Systems on LEO Satellite Downlink Coexistence in the C-Band

January 1, 2026·
Carla E. García
,
Michael N. Dazhi
,
Jorge Querol
,
Eva Lagunas
,
Mario R. Camana
,
Symeon Chatzinotas
· 2 min read
DOI
Abstract
The coexistence between terrestrial 5G networks and low Earth orbit (LEO) satellite systems in the C-band has raised increasing concerns due to the aggregated impact of out-of-band emissions (OOBE) from active antenna systems (AAS). This paper investigates the interference generated by terrestrial 5G downlink transmissions toward a ground-based LEO user equipment, with a particular focus on the role of AAS and different transmission schemes. Two operational modes are considered for the 5G remote radio unit (RRU): broadcast transmission, representing wide-coverage signaling with quasi-omnidirectional radiation characteristics, and data transmission, employing user-directed beamformed composite array patterns. A conservative coexistence scenario is analyzed, providing an upper-bound reference, in which multiple 5G RRUs are deployed around a ground LEO user operating in reception mode. In particular, pedestrian and vehicular ground users are considered to capture the impact of antenna characteristics. System-level simulations evaluate the aggregated interference power, interference-to-noise ratio (INR), and link-level metrics such as signal-to-interference-plus-noise ratio (SINR) and signal-to-noise ratio (SNR) under varying user distances, network densities, and satellite off-boresight angles. These findings highlight the importance of accounting for network densification and antenna pattern effects in C-band coexistence studies and regulatory assessments involving LEO satellite systems.
Type
Publication
IEEE Open Journal of the Communications Society
publication

Abstract & Overview

The coexistence between terrestrial 5G networks and low Earth orbit (LEO) satellite systems in the C-band has raised increasing concerns due to the aggregated impact of out-of-band emissions (OOBE) from active antenna systems (AAS). This paper investigates the interference generated by terrestrial 5G downlink transmissions toward a ground-based LEO user equipment, with a particular focus on the role of AAS and different transmission schemes. Two operational modes are considered for the 5G remote radio unit (RRU): broadcast transmission, representing wide-coverage signaling with quasi-omnidirectional radiation characteristics, and data transmission, employing user-directed beamformed composite array patterns. A conservative coexistence scenario is analyzed, providing an upper-bound reference, in which multiple 5G RRUs are deployed around a ground LEO user operating in reception mode. In particular, pedestrian and vehicular ground users are considered to capture the impact of antenna characteristics. System-level simulations evaluate the aggregated interference power, interference-to-noise ratio (INR), and link-level metrics such as signal-to-interference-plus-noise ratio (SINR) and signal-to-noise ratio (SNR) under varying user distances, network densities, and satellite off-boresight angles. These findings highlight the importance of accounting for network densification and antenna pattern effects in C-band coexistence studies and regulatory assessments involving LEO satellite systems.

Publication Metadata

  • Authors: Carla E. García, Michael N. Dazhi, Jorge Querol, Eva Lagunas, Mario R. Camana, Symeon Chatzinotas
  • Venue: IEEE Open Journal of the Communications Society (2026)
  • Research Areas: Satellite Communications, Beamforming & MIMO
  • DOI: 10.1109/ojcoms.2026.3726684
Satellite Communications Beamforming & MIMO