Communications technologies often evolve more quickly than the regulatory frameworks governing them. To keep pace, the International Telecommunication Union (ITU) World Radiocommunication Conference (WRC) revisits the ITU’s Radio Regulations governing radiofrequency spectrum use approximately every four years to accommodate new technologies and uses. Between WRCs, national administrations and ITU sector members (interested companies and trade associations, for example) meet in working parties to study how proposed rule revisions would impact existing and planned services.
Following four years of careful deliberations at the ITU working party level, more than 3,400 participants from 165 countries and ITU staff recently gathered at WRC-19 in Sharm El-Sheikh, Egypt. During the four-week conference, participants crafted regulatory pathways for emerging communication technologies, including a few listed below.
The ITU identified the millimeter wave frequency bands 24.25-27.5 GHz (24 GHz), 37-43.5 GHz, 45.5-47 GHz, 47.2-48.2 GHz, and 66-71 GHz for terrestrial systems that deliver high-throughput, low-latency 5G services.
Concern about interference to passive earth observation operations in the band adjacent to 24 GHz was one of the most contested issues at the conference. To mitigate those concerns, the ITU established new power limits. The compromise will require 5G base stations to comply with the following power limits in the 24 GHz band: -33 dBW/200 MHz initially, and then -39 dBW/200 MHz after 2027. News releases since the conference’s conclusion indicate that the weather scientist community that relies on the passive earth observation operations may not be pleased with the compromise and that the power limits may not adequately protect atmospheric water vapor sensors. On the other hand, the lower-than-requested power limits will likely increase the number of base stations required to achieve wide area 5G coverage in the band.
High-Altitude Platform Systems (HAPS)
Balloons, unmanned aircraft systems (UAS), and other HAPS technologies received allocations that will enable them to provide connectivity from altitudes between where terrestrial and satellite networks operate. The ITU identified the following frequency bands for HAPS use: worldwide (31-31.3 GHz, 38-39.5 GHz, 47.2-47.5 GHz, and 47.9-48.2 GHz) and Region 2 (the Americas) (21.4-22 GHz and 24.25-27.5 GHz).
Geostationary Satellite Orbit Satellites (GSOs)
Earth stations in motion (ESIMs) may now communicate with GSO satellites in the Ka-band (17.7-19.7 GHz and 27.5- 29.5 GHz).
Non-Geostationary Satellite Orbit Satellites (NGSOs)
Milestones – The ITU established milestone requirements for Mobile-Satellite Service (MSS), Fixed-Satellite Service (FSS), and Broadcasting-Satellite Service (BSS) systems operating in certain frequency bands between 10.7-51.40 GHz. In short, if a system does not meet the applicable milestone requirements, the ITU will reduce the number of satellites in a filing to the number of deployed satellites, subject to maximum limits.
- Milestone 1: 10% deployment within 2 years of the regulatory period end or January 1, 2021, whichever comes later. Operators may request waiver of Milestone 1, if the end of their regulatory period is earlier than November 28, 2022. Operators must include their deployment plans and other information to prove the “realness” of the NGSO system in their waiver requests. If the ITU cannot resolve a waiver request, it will refer the request to WRC-23 for consideration. A waiver grant would permit an operator to proceed to Milestone 2.
- Milestone 2: 50% deployment within 5 years of the regulatory period end or January 1, 2021, whichever comes later.
- Milestone 3:100% deployment (minus one satellite) within 7 years of the regulatory period end or January 1, 2021, whichever comes later.
V-band – After considering protections for GSO satellites and adjacent band passive earth observation services, the ITU created a new spectrum sharing regime for NGSOs operating in the frequency bands 37.5-39.5 GHz, 39.5-42.5 GHz, 47.2-50.2 GHz, and 50.4-51.4 GHz. Operators that did not file an ITU Notification before November 23, 2019. will now be subject to the ITU’s mandatory coordination procedures and will have to coordinate with all earlier filers prior to commencing operations. All NGSO systems will also need to comply with new single and aggregate power limits and out-of-band emission limits.
Short-duration NGSOs – The ITU permitted short-duration NGSO systems (operating for less than three years and proposing no replenishment satellites) to operate on a secondary basis in segments of the 137-138 MHz and 148-149.9 MHz bands. The new allocations are intended to relieve “spectrum congestion” issues faced by small satellite operators.
Radio Local Access Networks
WiFi technologies may now operate indoors and outdoors in band segments between 5-6 GHz subject to new operational restrictions.
Transportation Communications Systems – RSST and ITS
Railway radiocommunication systems between train and trackside (RSST) are train radio applications for “improved railway traffic control, passenger safety, and security for train operations.” Intelligent Transport Systems (ITS) technologies “connect vehicles, improve traffic management, and assist in safer driving.” While the conference did not allocate new spectrum for RSST and ITS, it did publish new recommendations and resolutions generally supporting spectrum harmonization for the technologies and encouraging regulators to update procedures for implementing these applications.
All changes to the Radio Regulations appear in the Provisional Final Acts. The ITU will likely release the Final Acts in six to nine months, and national administrations will commence rulemakings thereafter to implement the rules domestically.
The conference also decided the future agenda items that the ITU working parties will study and WRC-23 will resolve. Some of the most important future agenda items are highlighted below.
Mid-band terrestrial 5G spectrum
The ITU will consider identifying the frequency bands 3300-3400 MHz, 3600-3800 MHz, 6425-7025 MHz, 7025-7125 MHz, and 10.0-10.5 GHz for terrestrial 5G operations.
HAPS base stations
The ITU will evaluate whether frequencies below 2.7 GHz, including 694-960 MHz and various segments in the 1710-1885 MHz and 2500-2690 MHz bands, can accommodate 5G base stations on HAPS.
GSOs and NGSOs
The ITU will consider whether to permit ESIMs to communicate with NGSO Ka-band satellites and GSO Ku-band satellites. The working parties will also study the possibility of new spectrum allocations between 1695 and 3400 MHz for narrowband MSS systems supporting Internet of Things applications.
The ITU will deliberate several proposals to support further development of aeronautical applications:
- (i) UAS control and non-payload communication links using FSS Ku-band and Ka-band systems;
- (ii) the feasibility of a new aeronautical mobile-satellite (route) service allocation for both the Earth-to-space and space-to-Earth directions in all or part of the frequency band 117.975-137 MHz;
- (iii) changes to Appendix 27 (frequencies between 2850-22000 kHz) to identify any necessary modifications to the aeronautical mobile (route) service and introduce new digital aeronautical wideband HF systems; and
- (iv) spectrum needs for new non-safety aeronautical mobile applications for air-to-air, ground-to-air, and air-to-ground communications of aircraft systems, the possibility of deleting the “except aeronautical mobile” restriction in the 22-22.21 GHz band, and sharing and compatibility studies on the possibility of adding new primary allocations to the aeronautical mobile service for non-safety aeronautical applications in the frequency band 15.4-15.7 GHz.
WRC-19 succeeded in accommodating a number of new services and potentially increasing overall spectral efficiency. ITU participants, however, will have little time to rest. The next ITU working party meetings begin February 2020 in Geneva, Switzerland, and the ITU will need to study over thirty new items during the WRC-23 and WRC-27 preparation cycles.