The Committee on Radio Astronomy Frequencies (CRAF), an expert committee of the European Science Foundation (ESF), participated in the International Telecommunication Union (ITU) World Radiocommunication Conference, WRC19, held in Sharm El-Sheikh, Egypt for four weeks from 28th of October to 22nd of November 2019. The conference was attended by a record number of more than 3500 participants from more than 190 ITU member states, in addition to sector members representing major telecommunication companies and scientific organizations. CRAF, as an ITU sector member, represented the European radio astronomy observatories through the CRAF Chairman Michael Lindqvist from Onsala Space Observatory in Sweden and the Frequency Manager Waleed Madkour hosted at JIVE in Dwingeloo, Netherlands. CRAF teamed up with other radio astronomy groups and sector members at the conference such as the scientific committee on frequency allocations for radio astronomy and space science (IUCAF) and the Square Kilometre Array Observatory (SKAO) to align the radio astronomy activities.
WRCs are held every four years to revise and review global radio regulations based on proposed new spectrum allocations to radiocommunication services. Since its recognition as a radiocommunication service by ITU in 1959, the Radio Astronomy Service (RAS) has been allocated multiple frequency bands for astronomical observations over the consecutive WRCs. While no additional frequency allocations for RAS were included in the WRC19 agenda, the protection of the existing allocations from harmful interference was the main objective for RAS at this conference.
The agenda items of WRC19 covered frequency allocations proposed for a wide range of radiocommunication services. On top of these is the new 5G frequency allocations identified by the conference in the bands 24.25–27.5 GHz, 37–43.5 GHz and 66–71 GHz. The compatibility studies carried out by CRAF and other RAS groups showed the potential interfering impact of these allocations on the RAS observations using the 23.6–24 GHz and 42.5–43.5 GHz bands. The studies recommended introducing separation zones around radio observatories away from the 5G services to mitigate interference. The final acts agreed by the conference invited the national administrations to take the necessary actions in order to protect the RAS observatories from potential interference expected from the 5G services.
The radio interference to the RAS 1612 MHz band by Iridium satellites for more than 21 years now was one of the complex issues discussed at the conference. The Iridium satellite services will start operating for the Global Maritime Distress and Safety System (GMDSS), a safety service that is primarily provided by Inmarsat. The service was alloted a limited allocation of 5 MHz in the band 1621.35–1626.5 MHz and prevented from an additional 5 MHz allocation down to 1616 MHz. The European position supported by the RAS group opposed the full allocation in order to keep the frequency separation between the two services as far as possible. Moreover, hard regulatory limits were added in the final acts to urge Iridium satellite services to keep the interference levels to the RAS band within the defined thresholds.
The conference concluded several frequency allocations and regulations for other emerging radiocommunication services such as the High Altitude Platform Systems (HAPS) and land mobile and fixed services above 275 GHz. The regulatory protection conditions for the impacted RAS frequencies was correspondingly added.
The overall results of WRC19 are satisfactory for CRAF and the RAS community in general. The agenda of the next world radiocommunication conference WRC23 was also approved at the end of the conference. It is now necessary for the radio astronomy observatories to closely coordinate with their national administrations in order to follow up with the WRC19 results and prepare for the next cycle towards WRC23.