Practical IMT and EESS Spectrum Sharing in the 7 to 8 GHz Band

The 7.3 GHz (350 MHz bandwidth) Earth Observation Satellite (EOS) band, while not protected, is used for Passive Sea Surface Temperature (P-SST) measurements that provide important data for weather forecasts, coastal disaster prevention, climate modeling, and oceanographic research. The full 7 GHz band (7.125 to 8.4 GHz), which encompasses these EOS frequencies, is the largest contiguous block of potentially available mid-band spectrum and will play a significant role in meeting the anticipated demand for wireless services. A Real Time Geofenced Spectrum Sharing (RGSS) system is shown to be a practical and near term solution to spectrum sharing between P-SST measurements and 5G or 6G networks in the 7GHz band. RGSS enables IMT networks and EOS radiometers to share 350MHz of overlapping spectrum centered at 7.3 GHz. It prevents interference to P-SST measurements while simultaneously allowing IMT systems un-constrained access to the shared spectrum greater than 99.9% of the time. Subscriber impact during the less than 0.1 percent paused access time can be prevented by using 3GPP defined capabilities and O-RAN APIs to move subscribers to other frequencies. Paused access time data from a proof-of-concept RGSS system is available to academic, government, and industry researchers through a web or programmatic interface.

RF-Flashlight Testbed for Verification of Real-Time Geofencing of EESS Radiometers and Millimeter-Wave Ground-to-Satellite Propagation Models

A simple 'RF-flashlight' (or ground to satellite) interference testbed is proposed to experimentally verify real-time geofencing (RTG) for protecting passive Earth Exploration Satellite Services (EESS) radiometer measurements from 5G or 6G mm-wave transmissions, and ground to satellite propagation models used in the interference modeling of this spectrum coexistence scenario. RTG is a stronger EESS protection mechanism than the current methodology recommended by the ITU based on a worst-case interference threshold while simultaneously enabling dynamic spectrum sharing and coexistence with 5G or 6G wireless networks. Similarly, verifying more sophisticated RF propagation models that include ground topology, buildings, and non-line-of-sight paths will provide better estimates of interference than the current ITU line-of-sight model and, thus, a more reliable basis for establishing a consensus among the spectrum stakeholders.

Impact of new 5G network components on out-of-band emissions at 23.8 GHz

The impact of 5G networks transmitting between 24.25- 27.5 GHz on Earth Exploration Satellite Services (EESS) microwave sounders used to measure atmospheric water vapor and temperature was widely discussed and modeled in preparation for setting emission recommendations by International Telecommunications Union (ITU) at the 2019 World Radio Congress (WRC-19). Since then, two new classes of network devices - 5G repeaters and high transmission power User Equipment (UE) for fixed wireless services - have been introduced and deployed in 28 GHz networks with expectations that they will also be deployed at 24 GHz. This paper discusses the (potentially significant) increase in interference from these new components along with open questions related to their regulatory status. While this paper discusses increases in interference to 23.8 GHz EESS measurements from 5G transmissions in the "24 GHz" band, it is important to recognize that repeaters and high power UEs need to be considered when modeling interference from 5G/6G networks in all bands. This paper also touches on whether the current ITU process and methodology to regulate interference with passive sensors (vendor applied hardware-based filtering based on long-term network forecasts and worst-case Monte Carlo modeling) can keep up with rapidly changing wireless technology and the increased competition for spectrum.