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Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. The human eye can only detect only a small portion of this spectrum called visible light. A radio detects a different portion of the spectrum, and an x-ray machine uses yet another portion. Radio frequency is a part of the electromagnetic (EM) spectrum.
Electromagnetic waves are typically described by any of the following three physical properties: the frequency f, wavelength λ, or photon energy E. The RF is identified by frequency (Hertz or Hz) or wavelength (meters). Both terms reverse one another since the frequency goes up the wavelength goes down and vice-versa.
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The atmosphere of the Earth absorbs a big part of the EM spectrum, which may significantly diminish, and even blocks the frequencies. Nevertheless, it cannot absorb shorter radio waves usable in the transmissions from space to ground and vice-versa
The RF‘s measurement is Hz (hertz), which indicates the number of cycles per second upon transmission of a radio signal. The RF an electromagnetic invisible to the human eye. Technically, one Hz (hertz) equals one cycle per second.
The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from below one hertz to above 10exp(25) hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This frequency range is divided into separate bands, and the electromagnetic waves within each frequency band are called by different names; beginning at the low frequency (long wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end. The electromagnetic waves in each of these bands have different characteristics, such as how they are produced, how they interact with matter, and their practical applications.
Wireless communication technology is divided into different categories basing on the distance of communication. These are radio and television broadcasting, radar communication,
satellite communication, cellular communication, the global positioning system (GPS), WiFi,
Bluetooth, radio frequency identification systems, road toll systems, aeronautical navigation
and control, missile tracking, intelligent transport systems, baby alarms, walkie-talkies, radiation
therapy, wireless industrial automation, radio astronomy/space research, medical implants,
drones, alarms and more.
The wireless radio frequency is an electromagnetic wave frequency ranging between 3 kHz and 300 GHz; this includes those frequencies used for radar signals. Furthermore, the microwaves are radio wave with higher frequencies. Radio frequencies allow information to be transmitted over large distances by radio waves. The essential element to high-quality satellite communications is the assignment of radio-frequency spectrum to various types of services. Only a limited amount of such spectra is assigned to Earth-space radio links, and thus the available bandwidth must be used with a high degree of efficiency.
Frequency allocation (or spectrum allocation or spectrum management) is the allocation and regulation of the electromagnetic spectrum into radio frequency bands, normally done by governments in most countries.
A state is the proprietor of RF spectrum resource within its territory. It can license the
organisations in case they want to offer different services such as broadcasting and wireless
broadband requiring the RF spectrum in order to operate. The licence always determines the
limitation of that use an object, time and space in order to avoid the harming interferences.
Licensing is key to ensure that Radio Frequency (RF) interferences do not negatively impact satellite operators. Indeed, satellite signals can be overridden by a rogue or unlicensed system, which can jeopardize satellite operators’ activities and business. In order to ensure such situation does not happen, licensing procedures are inherently demanding.
Although the licensing of RF spectrum is conducted at national level, the radio waves cross
national borders, which requires the management to be international that can even make the
international mobile calls easier. Satellite operators have to deal with licensing of the space segment from the International Telecommunication Union (ITU).
Radio regulations are necessary to ensure efficient and economical use of the radio-frequency
spectrum by all communications systems, both terrestrial and satellite. While so doing, the
sovereign right of each state to regulate its telecommunication must be preserved. It is the role
of the International Telecommunication Union (ITU) to promote, coordinate and harmonize
the efforts of its members to fulfil these possibly conflicting objectives.
Several bodies set standards for frequency allocation, including:
International Telecommunication Union (ITU)
European Conference of Postal and Telecommunications Administrations (CEPT)
Inter-American Telecommunication Commission (CITEL)
The ITU organisation
The International Telecommunication Union (ITU), a United Nations organ, operates under a
convention adopted by its member administrations. The ITU publishes the Radiocommunication
Regulations (RR), which are reviewed by the delegates from ITU member administrations at
periodic World/Regional Radio Conferences (WRC/RRC).
From 1947 to 1993 the technical and operational matters were administrated by two committees:
the CCIR and the CCITT. The International Frequency Registration Board (IFRB) was responsible for the examination of frequency-use documentation submitted to the ITU by its member administrations, in compliance with the Radiocommunication Regulations, and for maintaining the Master International Frequency Register (MIFR).
Since 1994 the ITU has been reorganized into three sectors:
—The Radiocommunications Sector (ITU-R) deals with all regulatory and technical matters that
were previously handled respectively by the IFRB and the CCIR.
—The Telecommunication Standardisation Sector (ITU-T) continues the work of the CCITT, and
those studies by the CCIR dealing with the interconnection of radiocommunications systems
with public networks.
—The Development Sector (ITU-D) acts as a forum and an advisory structure for the harmonious
development of communications in the world.
The abundant and useful technical literature previously published in the form of reports and
recommendations by the CCIR and the CCITT have now been reorganised in the form of ITU-R and ITU-T series recommendations.
To improve harmonisation in spectrum utilisation, most service allocations are incorporated in national Tables of Frequency Allocations and Utilisations within the responsibility of the appropriate national administration. Allocations are: primary, secondary, exclusive or shared utilization, within the responsibility of national administrations.
Radio Communication Service
Radio Communication service is a service involving the transmission, emission and/or
reception of radio waves for specific telecommunication purposes, in the Radio regulation,
unless otherwise stated, any radio communication service relates to terrestrial. Radio
communication services that are assigned the frequency allocation by The International
Telecommunication Union are as follows:
1) Fixed service: A radio communication service between specified fixed points.
2) Fixed-satellite service: A radio communication service between earth stations at given positions, when one or more satellites are used; the given position may be a specified fixed point or any fixed point within specified areas; in some cases this service includes satellite-to-satellite links, which may also be operated in the inter-satellite service; the fixed-satellite service may also include feeder links for other space radio communication services.
3) Inter-satellite service: A radio communication service providing links between artificial
satellites.
4) Space operation service: A radio communication service concerned exclusively with
the operation of spacecraft, in particular space tracking, space telemetry and space tele-command. These functions will normally be provided within the service in which the space station is operating.
5) Mobile service: A radio communication service between mobile and land stations, or
between mobile stations (CV).
6) Mobile-satellite service: A radio communication service: – between mobile earth
stations and one or more space stations, or between space stations used by this service;
or – between mobile earth stations by means of one or more space stations. This service
may also include feeder links necessary for its operation.
7) Land mobile service: A mobile service between base stations and land mobile stations,
or between land mobile stations.
8) Land mobile-satellite service: A mobile-satellite service in which mobile earth stations
are located on land.
9) Maritime mobile service: A mobile service between coast stations and ship stations, or
between ship stations, or between associated on-board communication stations;
survival craft stations and emergency position-indicating radio beacon stations may
also participate in this service.
10) Maritime mobile-satellite service: A mobile-satellite service in which mobile earth
stations are located on board ships; survival craft stations and emergency position-indicating radio beacon stations may also participate in this service.
11) Port operations service: A maritime mobile service in or near a port, between coast
stations and ship stations, or between ship stations, in which messages are restricted to
those relating to the operational handling, the movement and the safety of ships and, in
emergency, to the safety of persons. Messages which are of a public correspondence
nature shall be excluded from this service.
12) Ship movement service: A safety service in the maritime mobile service other than a
port operations service, between coast stations and ship stations, or between ship
stations, in which messages are restricted to those relating to the movement of ships.
Messages which are of a public correspondence nature shall be excluded from this
service.
13) Aeronautical mobile service: A mobile service between aeronautical stations and
aircraft stations, or between aircraft stations, in which survival craft stations may
participate; emergency position-indicating radio beacon stations may also participate in
this service on designated distress and emergency frequencies.
16) Aeronautical mobile-satellite service: A mobile-satellite service in which mobile earth
stations are located on board aircraft; survival craft stations and emergency position-indicating radio beacon stations may also participate in this service.
Space radiocommunications services
The Radiocommunication Regulations refer to the following space radiocommunications
services, defined as transmission or reception of radio waves for specific telecommunications
applications:
—Fixed Satellite Service (FSS);
—Mobile Satellite Service (MSS);
—Broadcasting Satellite Service (BSS);
—Earth Exploration Satellite Service (EES);
—Space Research Service (SRS);
—Space Operation Service (SOS);
—Radiodetermination Satellite Service (RSS);
—Inter-Satellite Service (ISS);
—Amateur Satellite Service (ASS).
Frequency allocation
Frequency bands are allocated to the above radiocommunications services to allow compatible
use. The allocated bands can be either exclusive for a given service, or shared among several
services. Allocations refer to the following division of the world into three regions:
—region 1: Europe, Africa, the Middle East, the former USSR;
—region 2: the Americas;
—region 3: Asia Pacific, except the Middle East and the former USSR.
For example, the fixed satellite service makes use of the following bands:
—Around 6GHz for the uplink and around 4GHz for the downlink (systems described as
6/4GHz or C band). These bands are occupied by the oldest systems (such as INTELSAT,
American domestic systems etc.) and tend to be saturated.
—Around 8GHz for the uplink and around 7GHz for the downlink (systems described as
8/7GHz or X band). These bands are reserved, by agreement between administrations, for
government use.
—Around 14GHz for the uplink and around 12GHz for the downlink (systems described as
14/12GHz or Ku band). This corresponds to current operational developments (such as
EUTELSAT, etc.).
—Around 30GHz for the uplink and around 20GHz for the downlink (systems described as
30/20GHz or Ka band). These bands are raising interest due to large available bandwidth and
little interference due to present rather limited use.
The bands above 30GHz will be used eventually in accordance with developing requirements
and technology.
The mobile satellite service makes use of the following bands:
—VHF (very high frequency, 137–138MHz downlink and 148–150MHz uplink) and UHF (ultra
high frequency, 400–401MHz downlink and 454–460MHz uplink). These bands are for nongeostationary
systems only.
—About 1.6GHz for uplinks and 1.5GHz for downlinks, mostly used by geostationary systems
such as INMARSAT; and 1610–1626.5MHz for the uplink of non-geostationary systems such as
GLOBALSTAR.
—About 2.2GHz for downlinks and 2GHz for uplinks for the satellite component of IMT2000
(International Mobile Telecommunications).
—About 2.6GHz for uplinks and 2.5GHz for downlinks.
—Frequency bands have also been allocated at higher frequencies such as Ka band.
Allocations of military usage will be in accordance with the ITU Radio Regulations. In NATO countries, military mobile utilizations are made in accordance with the NATO Joint Civil/Military Frequency Agreement (NJFA).
Regulatory Structures
Radio regulations are formulated at several levels. At the international level, the Radiocommunication Sector of the International Telecommunication Union (ITU-R) formulates regulations through World Radiocommunication Conferences and recommendations through the work of its various study groups.
Much of the work of the ITU-R takes place through its study groups, which are further organized into working parties and task groups. These deal with specific areas or problems and provide studies of questions concerning technical and procedural aspects of radio communications. Study Group 7 has responsibility for use of the spectrum for scientific research (the science services): remote sensing systems are the concern of Working Party 7C (WP7C), and radio astronomy is the concern of Working Party 7D (WP7D). The other services under Study Group 7 are as follows: WP7A, time and frequency standards; WP7B, space research and Earth exploration-satellite services (mostly communications).
The work of the ITU-R results in an extensive system of formal documents that includes the following:
Questions—which specify the subjects to be studied within the study groups;
Recommendations and Reports—which record the conclusions from these studies; and
Regulations—which are adopted by adhering Administrations and have treaty status. Footnotes may provide additional information, and often provide protection to particular services on a primary or secondary basis.
WARC Radio frequecy allocation
Satellite technologies are more and more diverse and pervasive but they all rely on the same core element: the availability of radio frequencies that can be operated free from harmful interference. In order to ensure this availability, the Radio Regulations, the international treaty governing the use of the radio-frequency spectrum and the associated satellite orbits (both geostationary and non-geostationary), on the one hand allocate specific frequencies for various space applications, and on the other hand, contain detailed technical provisions and regulatory procedures to ensure the rational, equitable, efficient and economic use of spectrum/orbit resources.
But, with rapidly evolving technologies, innovative applications and new business models recently blossoming in the satellite industry, this treaty needs to adapt and be regularly updated: this is the role of World Radiocommunication Conferences. Such Conferences take place every four years and consider an agenda elaborated and agreed by the previous one. The various agenda items trigger three years of technical and regulatory studies performed within the ITU–R Study Groups to support the work of the Conference by providing possible alternative options to satisfy the needs expressed by the agenda item.
However, the essential satellite frequencies needed to realize this goal are under threat. It should be understood that these millimeter wave bands were made available a decade or more ago to ensure that future high-speed data satellite networks had ample spectrum — and in fact are the basis of products and services designed and built to operate today, to support hundreds of millions of users globally. The efforts of the international mobile telecommunication (IMT) community to identify these bands under WRC-19 Agenda item 1.13 exclusively for IMT-2020 (terrestrial 5G), put this promise and investment at risk.
Many of these bands, including 37.5–42.5 GHz and 47.2–50.2 GHz are co-primary for fixed-satellite services, and satellite networks are being planned and constructed for operation in these bands globally. As a case in point, Hughes is actively expanding its broadband-satellite services across the Americas in these bands, developing a new ultra-high-throughput (HTS) satellite (JUPITER 3), to be launched in 2021, joining two existing HTS satellites.
The agenda for the year 2019 contains several items related to satellite communications are : Providing additional spectrum for satellite broadband Internet access on moving platforms like ships, planes or trains; looking for a harmonized band for telemetry and telecommand of small satellites; setting the operational conditions of nongeostationary satellite systems in the 50/40 GHz range; providing additional spectrum in the same range for geostationary satellite systems; regulating the deployment of megaconstellations of non-geostationary satellite systems to prevent radio-frequency warehousing.
References and Resources also include:
National Academies of Sciences, Engineering, and Medicine. 2007. Handbook of Frequency Allocations and Spectrum Protection for Scientific Uses. Washington, DC: The National Academies Press. https://doi.org/10.17226/11719.
