Link Budget Analysis for Dual-Steering-Based Ground-to-Air and Satellite-to-Air Communications in 6G Networks

With the advent of 6G systems, non-terrestrial networks (NTNs) are emerging as a cornerstone for global, uninterrupted connectivity. This study evaluates the downlink link budget in a dual-steering TN–NTN architecture, where an aerial user simultaneously connects to both a terrestrial network and a LEO satellite network with on-board processing (OBP) for seamless connectivity. The analysis considers Ground-to-Air (G2A) and Satellite-to-Air (S2A) downlink link budgets under realistic 6G conditions, examining the effects of altitude, elevation angle, and frequency. The results demonstrate that minimum link margins of 16.04 dB for G2A and 13.4 dB for S2A are achievable, confirming reliable link performance for both configurations. We thoroughly describe the methodology used to perform the link budget computations. Additionally, we observe that in all cases, the results for the S2A scenario are relatively lower than those for G2A. This is attributed to the longer distance and multi-beam interference from other satellites. For example, at an elevation angle of 80°, the link margin in the S2A scenario is approximately 18 dB, whereas in the G2A case, it is about 45 dB—showing that the S2A link margin is nearly 60% lower.