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Frequency allocations accommodate new commercial applications.

Introduction

The 1992 World Administrative Radio Frequency Conference (WARC-92) was held in Torremolinos, Spain from February 3 until March 3, 1992. The conference attendees included 1400 delegates from 127 of the 166 countries that compose the International Telecommunication Union (ITU), as well as 32 international and regional organizations. The ITU is the international organization responsible for the regulation and planning of telecommunications worldwide, for the establishment of equipment and systems operating standards, for the coordination and dissemination of information, for the planning and operation of telecommunications services, and within the United Nations system, for the promotion of and the contribution to the development of telecommunications and the related infrastructures. The main responsibility of WARC is to review and update the International Radio Regulations, including the international Table of Frequency Allocations and the procedures for using the allocations. Delegates also look at existing frequency allocations and how to accommodate new global satellites and terrrestrial communication technologies and services, and how to meet the growing demands for existing services. They decide which new services to implement, how and when.

The agreements reached at WARC, known as the Final Acts, are similar to international treaties in that conference delegates must present these acts to their governments for approval. In the US, these acts must be ratified by the US Senate.

WARC-92 considered services operating in the frequency range from 3 MHz to over 150 Ghz. It was the first conference to consider commercial communication applications of satellites in low earth orbits (LEO) and highly elliptical orbits (HEO). Other services considered included shortwave or high frequency (HF) broadcasting; mobile and mobile-satellite services, including future public land mobile telecommunications systems (FPLMTS); digital audio broadcasting (DAB), broadcasting satellite service for sound (BSS-Sound); and wide RF band, high defintion satellite television (W-HDTV) services. The space research space operation, Earth exploration-satellite service, general-satellite service and wind profiler radar also were considered.

Shortwave or High Frequency Broadcasting

Shortwave or high frequency (HF) broadcasting is an existing service nearing saturation. The Final Acts of WARC-92 alloted a total of 790 khz of additional spectrum, including 5900 to 5950 khz, 7300 to 7350 khz, 9400 to 9500 khz, 11,600 to 11,650 khz, 12,050 to 12,100 khz, 13,570 to 13,600 khz, 13,800 to 13,870 khz, 15,600 to 15,800 khz, 17,480 to 17,550 khz and 18,900 to 19,020 khz. The extended bands are allocated on a worldwide basis. They are reserved for single sideband emission. They will become available for broadcast on 1 April 2007. After that date, existing stations of the fixed and mobile services will continue to be able to use the extended bands on a noninterference basis. The conditions of frequency use in the tropical bands, 2.5, 3 and 5 MHz, remain unchanged.

In addition, the introduction of single sideband techniques was agreed upon. The use of single sideband techniques, as opposed to the currently utilized technique of double sideband, will allow the use of 1.5 more channels, which takes up less bandwidth and results in greater spectrum efficiency

Mobile and Mobile-Satellite Services

Mobile and mobile-satellite services allow for systems provided by LEO satellites and FPLMTS, as well as public correspondence for aircraft passengers. These applications require the use of a region of spectrum currently occupied by existing fixed and mobile systems. WARC delegates sought to ensure that existing services were protected against harmful interference caused by these new services. As a means of protection, allocations were made through primary, permitted or secondary status, which ranks them in terms of protection and use of frequencies. Primary service has priority over any other. Permitted service has the same rights to protection as primary services except with regard to choice of frequencies for which the primary services have priority. Secondary services do not have the right of protection against signals from stations of the primary and permitted categories but can claim protection from other stations of the secondary service category.

Worldwide allocations were made on a primary and secondary basis for nongeostationary satellites, including small LEO operating below 1 Ghz. The primary allocations are 137 to 137.025 MHz, 137.175 to 137.825 MHz, 148 to 149.9 MHz and 400.15 to 401 MHz; the secondary allocations are 137.025 to 137.175 MHz and 137.825 to 138 MHz. Subject to coordination procedure for non-GSO satellites, a secondary allocation for mobile-satellite services was made in the 312 to 315 MHz band and a primary allocation for land-mobile service was made in the 149.9 to 150.05 MHz band.

For satellites of the mobile-satellite service operating above 1 Ghz, allocations were made in bands near 1.5, 1.6 and 2 Ghz, including primary and secondary allocations to the maritime-mobile satellite service, the land-mobile satellite service and the mobile-satellite service (MSS). In addition, an upgrade to a primary status in the 161 0 to 1613.8 MHz band was given to the Radio Astronomy Service and in the 20.1 to 20.2 Ghz and 29.9 to 30 GHz bands to MSS.

WARC delegates adopted a resolution to establish governing standards in the operation of LEO to ensure equitable and standard conditions of access for all members, and to guarantee proper worldwide protection for existing services and systems. A very limited number of LEO systems offering worldwide coverage can co-exist in any given frequency band. Therefore, it is necessary that standards be set for the coordination, sharing and operation of such systems.

FPLMTS

An upgrade of future public land mobile telecommunications systems FPLMTS) to primary status was granted in the 1700 to 2450 MHz band, which already had secondary status. The initial implementation of the terrestrial components of FPLMTS is expected for the year 2000 and for the satellite components by the year 201 0.

A primary worldwide allocation and a primary upgrade of the mobile service in the Europe/Africa region allows the introduction of aeronautical public correspondence (APC) in the 1670 to 1675 MHz band for transmissions from aeronautical stations and in the 1800 to 1805 MHz band for transmissions from aircraft stations.

DAB and BSS-Sound

On a worldwide basis, primary allocation in the 1452 to 1492 MHz band was made for the broadcasting satellite service (BSS). A recommendation was adopted to introduce broadcasting-satellite serive for sound (BSS-Sound) in the bands for this service and to hold a later conference to further develop and review BSS-Sound.

HDTV

No compromise was found on a worldwide unique frequency allocation for wideband HDTV. As of April 2007, the Europe/Africa and the Asia/Australia regions will be using the 21.4 to 22 Ghz band. In the Americas region, the 17.3 to 17.8 Ghz band will be used. Prior to 1 April 2007, HDTV may be implemented provided existing services are protected. After this date, existing services will be authorized to operate in those bands provided they do not interfere with the BSS HDTV nor claim protection from it.

Other Issues

The delegates adopted a resolution to provide assistance, including financial, to developing countries in their efforts to implement the decisions of WARC-92. In addition, the transfer of technology will be made available.

The 2025 to 2110 MHz band was allocated worldwide to the space research space operation and Earth exploration-satellite service on a primary basis. In addition, a resolution was adopted for a future conference to review space issues not dealt with by WARC-92.

No spectrum was freed in the 7 MHz band. Therefore, a recommendation was put forth that a future WARC consider possibly aligning the allocations of the amateur and broadcasting services around 7 MHz in order to provide a worldwide allocation.

A decision could not be made in providing the required spectrum to redress the imbalance between the uplink and downlink spectrum alloted to the FSS. Therefore, an extension was approved in the 13.75 to 14 Ghz band.

The general satellite service (GSS) proposal was not considered because there was not enough support. A recommendation was approved for the study of wind profiler radar characteristics and requirements with the intentions of allocating the necessary frequency bands around 50, 400 and 1000 MHz.

Applications

With the new allocations for nongeostationary satellites, LEO systems will be able to offer services in the VHF and UHF bands. They will also be able to provide basic message communications, one or two-way data communications and position location to small and light-weight (portable) terminals. Applications include emergency, data collection, paging and short messages to areas unserved or underserved by telecommunications. LEO systems will be able to provide mobile communication worldwide.

Future public land mobile communications systems are capable of providing a wide range of voice and nonvoice services, including personal communications with regional and international roaming. These universal personal telecommunications systems will allow every person to be reached via a wireless telephone, regardless of location. These systems have potential value to sparsely populated areas with limited communication facilities.

Aeronautical public correspondence is the system that provides public telecommunications to passengers of commercial aircraft. Currently, two different bands have been allocated for this service. The use of two different bands requires aircraft to carry two different types of equipment on-board in order to provide worldwide communications service to its passengers. A long-term future, worldwide allocation might facilitate a single system.

Digital audio broadcasting allows compact disc quality signals to be received on handheld or vehicular receivers without the fading distortion sometimes experienced with AM and FM radio reception. These systems use either terrestrial or satellite transmitters, or a combination of the two.(1) Broadcasting-satellite service for sound is individual reception with low cost portable and mobile receivers that use simple antennas. These receivers can operate in rural and urban areas.

Wind profiler radars are used by meteorological services to measure wind direction and speed as a function of altitude. This information is vital for the safety of air navigation, particularly at the time of landing. The absence of such information may have had an impact on several aircraft crashes in the past.

Conclusion

WARC-92 met its goal in establishing which radio communications services will be implemented, which frequency bands will be allocated, and how and when these decisions will take place. The Final Acts of WARC-92 have paved the way for some exciting new systems and services in the 21 st century.

This may have been the last conference of its kind. A recommendation to restructure the ITU has been presented. If it is adopted, the ITU will consist of three equal sectors, including development, standardization and radio communications. Also included in the restructuring is a change of the procedures for allocating frequency. A special conference to make a decision on the recommendation is scheduled for the end of this year.

References

[1.] WARC's Last Act?," IEEE Spectrum, February 1992, p. 20-23.
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Author:Stiglitz, Martin R.; Blanchard, Christine
Publication:Microwave Journal
Date:Jul 1, 1992
Words:1809
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