RF link budget sensitivity analysis of Bangladesh satellite-1 for reliable coastal and maritime communication

Abstract

This research presents a comprehensive RF link budget analysis for satellite-based non-terrestrial networks involving terrestrial, coastal, and maritime earth stations in tropical regions. The novelty and motivation of this work lie in the integrated evaluation of seasonal atmospheric attenuation, pointing mismatch effects, and terminal diversity to realistically quantify link margin degradation under practical operating conditions. The methodology combined ITU-R-based models for atmospheric attenuation with detailed uplink and downlink carrier-to-noise (C/N) calculations, followed by end-to-end C/N aggregation and modulation-dependent link margin assessment. Multiple communication scenarios were analyzed using QPSK, 8-PSK, 16-APSK, and 32-APSK under both vertical and horizontal polarizations. The results show that link margin decreased by approximately 14 dB when transitioning from QPSK to 32-APSK, with monsoon conditions causing an additional 0.01-5 dB degradation. The findings demonstrate that uplink limitations dominate system performance in maritime scenarios, highlighting the necessity of adaptive modulation and worst-case seasonal dimensioning to ensure high-availability satellite connectivity for next-generation 5G/6G networks in tropical climates.