JOINT PRECODING FOR MULTIPLE LOW EARTH ORBIT (LEO) SATELLITE COMMUNICATIONS WITH PER SATELLITE POWER CONSTRAINT

10.6329/CIEE.202312_30(2).0002

Yan-Yin He；Yu-Ching Sung；Shang-Ho Tsai

Low earth orbit (LEO) ； satellite communications ； precoding (beamforming) ； millimeter wave (mmWave) ； MU-MIMO system

電機工程學刊

30卷2期（2023 / 12 / 01）

53 - 60

英文

This work investigates a novel hybrid precoding scheme for space communications with per satellite power budget to better reflect the limited power issue in satellite systems, where interference mitigation is considered with the assumption of perfect synchronizations in multi-satellite joint transmissions. The system sum rate is maximized, while individual satellites in a Starlink can have different power budgets due to different satellites' battery capacity. We propose an iCSI (instantaneous channel state information) numerical solution based on convex optimization and an iCSI closed-form solution with significant complexity reduction. Moreover, to combat the feedback delay issue, we further introduce a closed-form solution using the long-term sCSI (statistical channel state information). We conduct simulations using a practical LEO ground track, and simulation results show that the proposed systems significantly outperform the traditional zero-forcing (ZF) system.