INTERNATIONAL TELECOMMUNICATION UNION NEW TECHNOLOGY AND RADIO REGULATION Dr. Pekka Tarjanne, Secretary General, International Telecommunication Union IEEE '94, Third International Symposium on Spread Spectrum Techniques & Applications, Oulu, Finland, 4 July 1994 Historical and current examples show dependence of growth of radiocommunication and new services on international radio regulations for allocation of frequency bands and control of interference. Recent ITU World Radiocommunication Conferences allocated frequency bands for future growth of mobile services, new mobile satellite applications and digital sound broadcasting. An increasingly congested spectrum and complex communication environment challenge the catalytic role of radio regulation. Spread spectrum technology may represent a critical contribution providing its performance and benefits for spectrum use are well understood. * * * Radiocommunication from its origin and by its nature has exploited new technology rapidly. It's first half century brought transoceanic telephone, television, radar and radio navigation, even radio astronomy. Later, radio spawned private telecommunication networks, competitive microwave and satellite transmission in public networks, and communications mobility. Radio and microchips seeded today's competitive, business-oriented, telecommunication revolution. But radiocommunication is not without frontiers and constraints. The frequency spectrum is limited, and radiocommunication depends upon regulation and co-ordination to avoid interference among services. The challenge for radio regulation is to facilitate new services while respecting needed continuing ones which pay their way. Indeed, only two technologies were ever legislated out, spark gap emission, and double sideband telephony for services where single sideband would be effective. With global growth of economies, and expansion of new radiocommunication services, the spectrum is increasingly stressed. The regulatory challenge today is not only to accommodate new services, but to assure equitable sharing of the spectrum resource among different services and different countries. To permit exploitation of global satellite communication from the 1960's, intricate frequency sharing arrangements were introduced in radio regulation to allow superposition of fixed-satellite service communications over terrestrial microwave links in the same frequency bands. Fullest sharing of the geostationary satellite orbit itself is achieved through technical criteria and intensive co-ordination among users. New networks are tailor fit into the orbit and coverage areas, according to its detailed technical characteristics and those of other networks concerned. In 1977, 1983 and 1988, with an eye to the future, new regulations reserved frequency bands and provisions to ensure access to the geostationary orbit for broadcasting or communications by any country for national services. The World Radiocommunication Conference, 1992, was the latest to make spectrum arrangements to facilitate new services and new technology, a quantum advancement of mobile communications by terrestrial and satellite means, as well as digital sound broadcasting, and high definition television. Some 230 MHz of spectrum was allocated near 2 GHz to provide for future mobile telecommunication using terrestrial and satellite networks. Additional spectrum was allocated for mobile satellite services using non-geostationary satellite orbits, and there are major organisations preparing to implement such systems. Fifty MHz bandwidth was allocated near 1.5 GHz for satellite digital sound broadcasting, and some 500 MHz was allocated for HDTV at 17 and 21 GHz. You know well that commercial operation of digital cellular systems, or so-called second generation mobile telecommunication systems, has started in a number of countries. ITU's Radiocommunication Study Group 8 studied digital cellular systems aiming at international Recommendations. It produced a Report in 1990, and a Recommendation in March, 1994. It lists 4 digital cellular systems being installed or planned; namely GSM 900/DCS 1800, North American D-AMPS, North American CDMA and Japanese PDC. Although these systems are neither compatible nor share a common frequency band, the Recommendation is expected to be a basic reference for digital cellular systems through this decade. The North American CDMA system is the first spread spectrum system specifically included in such an internationally agreed Recommendation. ITU studies started in 1986 on Future Public Land Mobile Telecommunication Systems (FPLMTS), or world-wide third generation mobile telecommunications. It was clear that standardisation should not inhibit technological development or competition, but that a certain compatibility and commonality could reinforce global use and reduce costs. Speech coding common with network standards, for example, would be an important advantage. Eight ITU-R Recommendations now describe the general concept, framework for services, network architectures, satellite operation, application for developing countries, radio interfaces and spectrum considerations. Other Draft Recommendations on performance requirements, security principles and framework for network management have just been approved. The Task Group has had participation of some 100 experts from fifty organisations representing global mobile radio interests. This work is closely co-ordinated with the ITU-T Standardisation Sector, which itself is creating tens of complementary Recommendations on network aspects. The work aims to provide an umbrella of compatibility and interoperability for a radio infrastructure capable of offering a wide range of services around the year 2000 in many different operating environments. It was on the basis of these studies that the WARC '92 identified 230 MHz of global frequency spectrum around 2 000 MHz for the use by FPLMTS around the year 2000. The common global frequency allocation represented strong support for compatibility, though detailed implementation of the allocations is a national matter. Currently, a Recommendation is being drafted to guide selection of radio technologies for FPLMTS. A number of proposals of TDMA and CDMA systems are foreseen. Some of your organisations already participate in this work; proponents are encouraged to assure that necessary information is provided to a meeting of the Task Group to be held in October, 1994. Naturally, a criterion for judgement is efficiency of use of the spectrum. Efficiency concerns not only that of a single service, but that of the aggregate of services sharing a given portion of the spectrum. In radio regulatory parlance, land mobile is a service, and (microwave) radio relay is fixed-service. In a band shared by two or more services, efficiency should consider and credit aggregate throughput. The World Administrative Radio Conference held in 1992 enlarged the possibilities of mobile communications via satellite. A number of low-Earth orbiting satellite systems have subsequently been announced, as well as enhancement of geostationary satellite systems. These systems are expected to provide a variety of services including personal communications, both voice and data, paging, position determination and short message transmission. Some of the proposals could be extended to form a part of satellite component of the FPLMTS. Again both TDMA and CDMA systems are on the table. The Conference allocated frequency bands to the mobile-satellite service on the basis of sharing with other services. Frequency sharing criteria and international co-ordination procedures have become critical paths for successful implementation. While about 90% of satellites, more than 5000, are already in non-geostationary orbits, only a small proportion of these represent public communication, mainly to cover polar regions inaccessible to GSO satellites. Use of the allocated frequency bands for global non- geostationary satellite mobile communication poses more complex technical co-ordination. The '92 Conference did not have at hand the ultimate technical basis for interference assessment among LEO's, and with GSO's, sharing the same bands. A Conference Resolution 46 provided procedures and guidelines, but left to the ITU-R Study Groups to develop calculation methods and criteria for assessment of interference compatibility among different users. So far some Recommendations have been prepared but much more work is still to be done compared with the pace of business development. While I have focused on mobile service because of the theme of your conference, timely radio regulation and co-ordination are key to continuing expansion of fixed satellite service applications, implementation of digital sound broadcasting, and other services. For some time, increasing difficulties to co-ordinate fixed satellite service assignments have been seen in some regions and frequency bands, particularly for fixed-satellite systems in the most used bands. Co-ordination negotiations are long and difficult, satellites are sometimes brought into use without (successful) co-ordination. In-orbit satellites are sometimes relocated without proper co- ordination. Some say that these bands have reached their saturation level of exploitation. On the other hand, some other frequency bands (as for example the 11-12 GHz satellite broadcasting bands) remain largely unused. It is a controversial question whether spectrum scarcity may partly reflect lack of responsive adjustments to Radio Regulations. Frequencies and orbit positions planned in 1977 and 1983 for broadcasting satellites remain largely unused, partly because rapid advances in technology favoured other alternatives. Some regulatory procedures which extend over years might also be reviewed, as the tolerance of 9 years delay before abandoning a proposed satellite network not brought into service, and comparable procedures. The 1992 ITU World Administrative Radio Conference adopted an almost- world-wide band for digital sound broadcasting (DSB) near 1.5 GHz, and another at 2.6 GHz, following CCIR Recommendations concerning this new technology. It is an application of spread spectrum technology, using coded orthogonal frequency division multiplex (COFDM). Originally conceived for satellite broadcasting, DSB is now considered for satellite, terrestrial, and hybrid application. Terrestrial emission might alternatively be "in band" with existing FM or television channels. A long period of phasing-out other services at 1.5 GHz band (until 2007 in several countries) will affect the introduction of satellite systems, but provision has been made for the implementation of early systems. Different solutions may be developed for different countries depending on local availability of spectrum. In Europe, some sort of regional plan might be implemented. Digital sound broadcasting will provide superior quality and extended coverage for future sound broadcasting services. Studies are centred on the advantages and disadvantages of "in band" systems. Development of receivers, including antennas, is underway both for proposed in-band and new-band systems. I have taken the opportunity to speak of "new technology and radio regulation" because it is relevant to the spread spectrum technology of your conference. Spread spectrum is already a feature of some terrestrial mobile systems and of proposals for mobile satellite service. Spread spectrum experts show its advantages for performance, and for efficiency of spectrum use. Time-division multiple access proponents may dispute the performance advantage but acknowledge spread spectrum's clear advantage for superposition in a shared frequency band with other services, as microwave radio relay. To realise full advantage, spectrum management people must learn well the application of spread spectrum principles. There should be further development of the concept of aggregate throughput in an environment shared with different radiocommunication systems. - - -