Assessment and Mitigation Approaches of 5G C-Band Interference With Aeronautical Radar Altimeter

The recent deployment of 5G technology in the C-band has raised concerns regarding potential interference with aeronautical radar altimeters. 5G systems in the C-band operate within a frequency range of 3.7-3.98 GHz, which closely aligns with the operational frequency of radar altimeters, falling within the range of 4.2-4.4 GHz. This proximity in operational frequencies increases the possibility of interference between the two systems. In this paper, we explore two primary objectives: first, to examine the potential for interference between the 5G C-band and radar altimeters, and second, to develop techniques for mitigating this interference. To achieve these objectives, we assess interference in a real-world scenario, where multiple Base Stations (BSs) are deployed to serve an operational runway. Additionally, two interference management techniques were proposed and evaluated within the assessed real-life scenario. The first involves the implementation of adaptive BS using the Power Control (PC) method, which aims to mitigate interference with minimal impact on coverage by adjusting the transmitting power for the BS that contributes the most to the interference model. A modification to this technique was applied to loop over the coverage areas instead of individual BSs. This technique is useful in scenarios where BSs are implemented close to each other with overlapping coverage. Lastly, a Sequential Quadratic Programming (SQP) optimization algorithm was developed to optimize the locations of BSs, minimizing interference while maintaining coverage. This work has explored the impact of potential interference between 5G in the C-band and radar altimeters and suggested practical methods to allow the coexistence of both systems, thereby ensuring aviation safety and fulfilling the telecommunication sector’s objectives.