TY - GEN
T1 - 3D Frequency-Dependent Rainbow Beamforming Design for High-Throughput LEO Satellite Networks
AU - Park, Juha
AU - Kim, Seokho
AU - Shin, Wonjae
AU - Poor, H. Vincent
N1 - Publisher Copyright: © 2025 IEEE.
PY - 2025
Y1 - 2025
N2 - Low Earth Orbit (LEO) satellite communications (SATCOM) offer high-throughput, low-latency global connectivity to a large number of users. To accommodate this demand with limited hardware resources, beam hopping (BH) has emerged as a prominent approach in LEO SATCOM; however, its time-domain switching mechanism confines coverage to a small fraction of the service area during each time slot, exacerbating uplink throughput bottlenecks and latency issues as the user density increases. Meanwhile, wideband systems experience the beam-squint effect, where analog beamforming (BF) directions vary with subcarrier frequencies, hindering the performance of wideband SATCOM. In this paper, we put forth 3D rainbow BF, employing a joint phase-time array (JPTA) antenna with true time delay (TTD) to intentionally widen the beam-squint angle, steering frequency-dependent beams toward distributed directions. This novel approach enables the satellite to serve its entire coverage area in a single time slot. By doing so, the satellite simultaneously receives uplink signals from a massive number of users, significantly boosting throughput and reducing latency. To realize 3D rainbow BF, we formulate a JPTA beamformer optimization problem and address the non-convex nature of the optimization problem through a novel joint alternating and decomposition-based optimization framework. Through numerical evaluations, we demonstrate that the proposed rainbow BF-empowered LEO SATCOM achieves up to 3.8-fold increase in uplink throughput compared to conventional BH systems.
AB - Low Earth Orbit (LEO) satellite communications (SATCOM) offer high-throughput, low-latency global connectivity to a large number of users. To accommodate this demand with limited hardware resources, beam hopping (BH) has emerged as a prominent approach in LEO SATCOM; however, its time-domain switching mechanism confines coverage to a small fraction of the service area during each time slot, exacerbating uplink throughput bottlenecks and latency issues as the user density increases. Meanwhile, wideband systems experience the beam-squint effect, where analog beamforming (BF) directions vary with subcarrier frequencies, hindering the performance of wideband SATCOM. In this paper, we put forth 3D rainbow BF, employing a joint phase-time array (JPTA) antenna with true time delay (TTD) to intentionally widen the beam-squint angle, steering frequency-dependent beams toward distributed directions. This novel approach enables the satellite to serve its entire coverage area in a single time slot. By doing so, the satellite simultaneously receives uplink signals from a massive number of users, significantly boosting throughput and reducing latency. To realize 3D rainbow BF, we formulate a JPTA beamformer optimization problem and address the non-convex nature of the optimization problem through a novel joint alternating and decomposition-based optimization framework. Through numerical evaluations, we demonstrate that the proposed rainbow BF-empowered LEO SATCOM achieves up to 3.8-fold increase in uplink throughput compared to conventional BH systems.
KW - frequency-dependent beamforming
KW - Low Earth orbit (LEO) satellite
KW - sixth-generation (6G) networks
UR - https://www.scopus.com/pages/publications/105036363312
UR - https://www.scopus.com/pages/publications/105036363312#tab=citedBy
U2 - 10.1109/GLOBECOM59602.2025.11431679
DO - 10.1109/GLOBECOM59602.2025.11431679
M3 - Conference contribution
T3 - Proceedings - IEEE Global Communications Conference, GLOBECOM
SP - 5832
EP - 5837
BT - GLOBECOM 2025 - 2025 IEEE Global Communications Conference
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2025 IEEE Global Communications Conference, GLOBECOM 2025
Y2 - 8 December 2025 through 12 December 2025
ER -