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Spectrum Management: Into the 21st Century
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2.1 The characteristics of the radio spectrum and details of how the RA manages it have been set out in some detail in the consultative document, the RA's annual report and accounts and business review and the series of independent spectrum reviews . The economic impact study referenced above also contains much detail on current spectrum usage.
2.2 The radio spectrum is usually taken to comprise that part of the electromagnetic spectrum between frequencies of 3 kHz and 3000 GHz. With present technology, it is not yet practical to use spectrum much above 100 GHz. Different frequencies have different characteristics that make them suited for particular applications. Broadly speaking, lower frequencies travel further so are useful for applications such as broadcasting. Higher frequencies travel less far, which limits their usefulness in some respects but means they can be re-used more intensively, and have greater information carrying capacity. Technical developments are continually raising the upper limit of the usable spectrum and developing ways of using lower frequencies more intensively. However, technology is being outpaced by rapidly growing demand for spectrum. The problem is greatest between 30 MHz and 30 GHz. These are currently the most useful frequencies and so are most in demand. It is in that part of the spectrum that problems of actual or incipient congestion are worst. The problems are greatest in and between major cities where radio traffic is most intense.
· Below 1 GHz Most of this part of the spectrum is taken up by broadcasting, defence, private business radio (pbr), previously known as private mobile radio (pmr), and cellular telephony. There is severe congestion in the pbr bands, where demand continues to grow steadily, and increasing pressure on cellular telephony bands.
· Between 1 and 3 GHz Defence and civil aviation have sizeable allocations. Other significant users include private user and telecommunications operators’ fixed links, PCN services, such as Orange and Mercury One 2 One, and the use of radio in television programme production. Applications in this part of the spectrum reflect the propagation characteristics that limit range and make greater re-use possible. Technical improvements make it possible to contemplate mobile services at frequencies above 2 GHz, which would not have been feasible a few years ago.
· From 3 to 30 GHz Mobile use is not currently attractive in this range because propagation characteristics limit coverage. Defence and telecommunications fixed links (BT Mercury, and other private users) are the major users.
· Above 30 GHz Radio waves at these high frequencies are severely attenuated by the atmosphere so these bands can be used only for short-range communication. Apart from fixed links at 38 GHz and higher frequency bands, there is little commercial exploitation at present. The RA is encouraging greater use as a means of reducing congestion at lower frequencies.
2.3 Economic growth, the introduction of competition and choice in telecommunications and broadcasting and technical innovation have fuelled a seemingly insatiable demand for spectrum. Annual growth ranges from a steady 5% for standard pbr through 30% for trunked public access mobile radio (pamr) to 60% for cellular telephony. The pressure on the available spectrum is rising and is increasingly difficult to accommodate.
· PBR - particularly in urban areas.
· Mobile telephony - both for existing service growth and new operators.
· Terrestrial broadcasting - introduction of additional services with national coverage is possible only with digital technologies that will require wholesale replacement of transmitters and conversion or replacement of receivers.
· Fixed links - in telecommunications trunk networks.
2.4 The radio spectrum has to be managed and carefully planned.
· Interference Transmissions interfere with each other and become unusable unless they are sufficiently separated in terms of frequency, geographical location or time. Even the best-designed equipment transmits or receives unwanted signals, including harmonics and intermodulation products , which can cause interference. Minimising interference while making the best possible use of the spectrum requires careful coordination by the spectrum manager.
· Equipment limitations Most radio equipment can operate over only a limited range of frequencies. A stable but responsive framework of strategic spectrum management fosters investment in radio infrastructure and systems and helps manufacturers design and produce equipment that meets users' needs.
· International obligations Radio waves do not respect national frontiers. Necessary international coordination and management is undertaken through the International Telecommunication Union (ITU), an agency of the United Nations. International coordination also facilitates ‘roaming’ so that equipment can be used in a number of countries and manufacturers benefit from larger markets. International agreements apply to both allocation and assignment . The Radio Regulations promulgated by the ITU have international treaty status.
2.5 This involves dealing with a number of technical and other problems and balancing conflicting considerations.
· Technical complexity Spectrum planning is complicated by the increasing density of radio traffic and the closeness of the UK to its geographical neighbours. The RA has made, and is continuing to make, considerable investment in modern spectrum management systems and methods.
· International coordination Because of the proximity of the UK in radio terms to neighbouring countries, international agreements and coordination impose considerable constraints on spectrum management in the UK. Decisions to transfer spectrum from one service to another cannot be taken unilaterally but require international clearance, which takes time and cannot be taken for granted .
· Investment in equipment Users often make considerable investments in equipment. Sudden changes in the frequencies allocated to services are likely to impose substantial costs. The RA endeavours to give reasonable notice of changes, which may be of a similar order to the lifetime of equipment in service, although this may slow desirable developments.
· Equipment availability It may not be an efficient use of spectrum to allocate frequencies to a service before the equipment to provide it becomes commercially available. Increasingly, technical specifications are determined internationally so that equipment can be used across frontiers. This promotes wider markets for manufacturers to exploit but lengthens the time needed for new equipment to become available.
2.6 Because of these factors, lead times for change may be considerable. Spectrum management and planning has, therefore, to be carried out on a strategic basis. In 1995, the RA published its first spectrum strategic plan , which set out its view of likely developments across the radio spectrum. This is revised, updated and re-issued annually to help UK radio users, manufacturers and service providers to plan ahead. The central problem for spectrum managers is how to respond within a framework of strategic planning to the pace of short term pressures generated by technical change and the introduction of competition.
2.7 The RA manages nearly all the civil radio spectrum in the UK. The Ministry of Defence is responsible for spectrum allocated for military use and certain other Government departments and bodies (such as the Home Office, Scottish Office and the Directorate of Airspace Policy) for specific blocks of spectrum for use by services for which they have responsibility. The various spectrum management bodies are being brought together and coordinated by a national radio spectrum committee on the lines recommended by the Stage 3 Spectrum Review. A number of private sector bodies have been established in the mobile radio and programme making and entertainment fields to manage blocks of spectrum allocated for particular uses.
2.8 The RA is responsible for enforcement against illegal transmitters, which often interfere with safety-of-life services and other licensed users; ensuring compliance with licence conditions; and resolving complaints about interference.
2.9 The RA also represents the UK in international radio fora in Europe and worldwide, where key decisions are taken on international spectrum planning and on harmonised technical specifications for equipment. In view of the importance of radio to the UK economy, the RA will continue to play a leading role in these bodies.
2.10 The economic impact study mentioned above examined the contribution of the RA through its various activities to the economic impact of radio and to competitiveness. It concluded that the RA had played an important and valuable role in making spectrum available in a timely manner, coordinating discussions between parties where spectrum was shared, securing international agreement and promoting self-management by users where appropriate; and that these activities had led to significant economic benefits through the early introduction of new technology and services compared to the UK's international competitors. The Government believes that the proposals for change that are discussed in following chapters will enable the RA to do even more to promote wealth creation and enhance competitiveness.
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