WRS-22: Taking stock of terrestrial services

By ITU News

All devices and services relying on radio waves require a share of the world’s radio frequency spectrum.

​​​​​​​​​​​​​​​​​​Every time you make a call, catch a flight, browse the Internet on your smartphone, listen to the radio in your car, or check the weather forecast, you benefit from the vital yet imperceptible global spectrum that is allocated and harmonized by the International Telecommunication Union (ITU).

ITU – working through its Radiocommunication Sector (ITU-R) and associated Radiocommunication Bureau (BR) – manages the world’s finite spectrum through continual, worldwide consultation, cooperation, and coordination.

Much of this happens within the Bureau’s Terrestrial Services Department, headed by Nikolai Vassiliev.

What are terrestrial services?

Terrestrial services constitute all radio stations located on the ground, at sea, or in the air up to 50 kilometres in altitude, Vassiliev explained at the World Radiocommunication Seminar (WRS) held recently at ITU’s Geneva headquarters.

Fifteen different radiocommunication services — defined as the transmission or reception of radio waves for specific telecommunication purposes — qualify as terrestrial.

“Each service can have several applications, such as fixed wireless access, broadcast television, or even backhaul links of mobile network that connect base stations to the core network,” Vassiliev added.   

Regulatory instruments

Several international regulatory instruments exist for terrestrial services. First and foremost are the Radio Regulations, and second are Regional Agreements governing specific services in certain regions of the world. All these regulations and agreements are maintained by ITU.

The Radio Regulations exist to ensure interference-free operation of radio stations, provide a stable planning environment for government and industry, and facilitate the harmonization of spectrum use worldwide.

Such stations should not be confused with the general public’s notion of radio stations – i.e., the radio channels that broadcast the AM or FM signals received by a car radio.

Radio stations, or simply “stations,” are defined in the Radio Regulations as: “One or more transmitters or receivers or a combination of transmitters and receivers, including the accessory equipment, necessary at one location for carrying on a radiocommunication service, or the radio astronomy service.” 

So, in the international regulatory context, a terrestrial radio station is the actual equipment located at a specified location on Earth – whether on land, at sea or in the air – and used in providing a radio service.

Provisions in the Radio Regulations treaty define frequency “blocks” and allocate those blocks to compatible services based on specific conditions.

The treaty also contains the procedures to coordinate and register stations in the Master International Frequency Register (MIFR) and offers guidance for resolving cases of harmful interference.

In some cases, the Radio Regulations identify frequencies and establish rules for specific applications, such as international mobile telecommunications (IMT), high-altitude platform systems (HAPS), and radio local area networks (RLANs) – the radio systems providing wireless access between computer devices and through a gateway to the global Internet.

Beyond ITU, agreements between countries or within other international organizations, such as the International Civil Aviation Organization (ICAO), may also regulate the usage of terrestrial radio stations in specific frequency bands.

How spectrum is shared

International spectrum-sharing is becoming increasingly complex, amid the need to accommodate burgeoning rates of Internet traffic and data-hungry devices.

Nikolai Vassiliev outlined two basic approaches for sharing spectrum:

• frequency coordination, based on real frequency needs, which enables flexible and efficient spectrum use, assuming neighbours can cooperate with each other.
• frequency planning, which, in contrast, is more about ensuring equitable access, even though this is not always ideal for efficient spectrum use.

Countries have sovereignty over the use of radio frequencies within their territories.  Addressing questions about the potential for differences between national and international regulations, Vassiliev noted three instances where “it is essential that they pay particular attention to international regulations.”

In planned bands, international regulations prevail. “If a country is a party to a Regional Agreement having a frequency plan, the administration must check if the station is in compliance with the relevant provisions of this Agreement.”

Similarly, for bands shared between terrestrial and space services,the international rulesshould be taken into account, since even terrestrial stations located well inside borders can mutually interfere with space stations, “which are everywhere.”

Thirdly, stations with potential to interfere with a neighbour’s services, must be looked at closely, whether it is due to proximity to a national border or to the use of frequencies that propagate over long distances. “Even a radio station placed well inside a country’s borders can transmit signals that propagate thousands of kilometres in lower bands,” Vassiliev pointed out.

Maintaining the MIFR

The MIFR is a worldwide database of operational radio stations, currently encompassing about 3.1 million terrestrial frequency assignments. “Around 70 per cent of ITU Terrestrial Services Department activities are dedicated to maintaining it,” N. Vassiliev estimated.  

Recording a frequency in the MIFR, although sometimes a complex endeavour, gives a radio station operator several advantages. All stations in the international register are protected from interference, whereas unrecorded radio stations must undergo lengthy coordination efforts.

“You get full protection if your station is in a planned frequency band,” explained Vassiliev. “Moreover, countries often look at the MIFR to determine which bands to assign. Recording in the MIFR offers a right of international recognition.”

The Terrestrial Services Department, despite its name, also collects vital information about maritime services, including lists of coast and ship stations, which are also available 24/7 online in the Maritime Access and Retrieval System (MARS).

“We also maintain databases of oceanographic radars and communications for emergencies and disaster relief,” he added.

Evolving terrestrial tools

Following broader software trends, spectrum management tools are increasingly moving online.

The ITU Radiocommunication Bureau, in step with this trend, is creating online versions of its frequency databases and other tools.

Currently, the eTerrestrial online portal enables ITU members to check the MIFR and validate frequency notices before official submission to WISFAT: the web interface for submission of frequency assignments/allotments for terrestrial services.

TIES (Telecommunication Information Exchange Service) users can manage frequencies and filings for broadcasting services through the eBroadcasting platform. Similar tools will be available soon for the fixed, mobile, and other terrestrial services via eFXM platform. Such tools can even predict propagation and make calculations in line with ITU-R Recommendations using ePropagation.

These online tools complement a system called TerRaSys, which the Radiocommunication Bureau uses to process frequency notices sent by government administrations.

“TerRaSys will be gradually moved to the web to make it more user-friendly,” Vassiliev noted, “in addition to a software package called BRIFIC, currently on DVD.”

This special ITU News blog series features content from the 30th World Radiocommunication Seminar, including a closer look at the latest trends in broadcasting, international mobile technologies, maritime communications, space services, and more.

The series will conclude a preview of the World Radiocommunication Conference (WRC-23), set to take place in Dubai from 20 November to 15 December 2023.

Image credit: VladSV via Shutterstock