Understanding 5G Frequency Allocation and its Impact on Airliner Radar Altimeters

The Federal Communications Commission (FCC) has approved a specific frequency band for 5G cellular service, which is a crucial step in rolling out advanced mobile communication technology. However, this approval and allocation of frequency bands are not without complexities, especially when it comes to ensuring compatibility with existing aviation technology.

The 5G Frequency Range

The FCC has allocated the range from 3.7 GHz to 3.98 GHz for 5G cellular service. This allocation follows international regulations and is designed to ensure seamless integration with the global radio communication network. It is important to note that such allocations are typically made with strict adherence to international standards to minimize interference among different systems.

FAA Regulation and 4.2 to 4.4 GHz Range

Additionally, the Federal Aviation Administration (FAA) has a regulation that covers the range from 4.2 GHz to 4.4 GHz. This range is crucial as it is used by radar altimeters, which are essential for ensuring the safety of aviation operations. These altimeters provide critical height information to pilots, helping them to land safely and navigate their aircraft effectively.

Compatibility Challenges and Boeing Intervention

One of the key challenges in this frequency allocation is the potential for interference between 5G signals and radar altimeters. Boeing, a leading aviation company, highlighted the difficulty in ensuring the continued reliability of radar altimeters in the presence of 5G signals. The issue arises because older radar altimeters, which have been in use since 1970, do not filter out-of-band signals as newer systems do. This can potentially lead to unreliable readings and compromise the safety of aviation operations.

Boeing’s concern is significant given the widespread use of radar altimeters in modern aviation. To address this issue, Boeing proposed an additional guard band of 100 MHz on the 5G side to prevent interference. The reduction in available bandwidth from 3.7 GHz to 4.2 GHz to 3.7 GHz to 4.0 GHz demonstrates the struggle between advancing 5G technology and preserving the safe operation of these critical avionics systems.

Recent Developments and FAA’s Request

Despite the complicated allocation, the journey to fully utilizing 5G technology is not over. Recently, the FAA has requested a moratorium on deploying 5G in close proximity to airports. The FAA argues that the installation of up-to-date radar systems in airplanes should be prioritized, as this would ensure that the safety of the aviation industry is maintained.

The FAA’s request highlights the ongoing tension between technological advancement and operational safety. While 5G promises significant benefits in terms of speed and connectivity, it is imperative that these benefits do not come at the expense of aviation safety. The FAA’s request for a moratorium indicates a commitment to ensuring that pilots and passengers remain safe as we transition to a more connected era.

Conclusion and Future Outlook

The allocation of frequency bands for 5G cellular service is a significant milestone, but it is clear that ensuring compatibility with existing aviation technology is an ongoing challenge. The involvement of Boeing and the subsequent requests from the FAA demonstrate the complexity of integrating new technologies with legacy systems.

As we move forward, it is crucial to continue working on solutions that balance the benefits of cutting-edge technology with the safety and reliability of aviation operations. The ultimate goal should be to ensure that the progress in 5G does not compromise the safety of air travel.

For more information on 5G frequency allocation, radar altimeters, and the latest developments in aviation technology, please refer to relevant regulatory documents and the latest industry publications.