ITU-R - International Telecommunication Union/ITU Radiocommunication Sector
Scope
"Introduction and summary Interim Working Party 8/13 was set up by Decision 69 in 1985 with the task of investigating the form of Future Public Land Mobile Telecommunication Systems (FPLMTS) with particular regard to the overall objectives@ suitable frequency bands and the degrees of compatibility or commonality and which has resulted in the preparation of new Recommendation 687 on FPLMTS. This Report summarizes the result of the study. From the beginning of the study it was apparent that a light-weight personal pocket radio would be a dominant feature of FPLMTS. Most administrations advocated the desirability of such a personal station (PS) being usable anywhere world-wide@ with the inherent implication of a requirement for a single radio interface standard. However@ considerations of the varieties of radio coverage scenarios for personal communications (from very short range ones for use with in buildings or urban areas through medium range suburban and longer range rural coverage@ together with the desire for links to aircraft or satellites) indicated that a number of RF transmission requirements and frequency bands are likely to be required. Moreover@ a tandem link could well be involved from the PS via another mobile connection. There is a possibility that the final link to the PS could be the same. However@ the situation of the vehicle mounted mobile accessing terrestrial links is different@ and some administrations emphasized the much reduced requirements for inter-regional roaming (although international roaming within a region will be a requirement). Hence@ it was agreed that greater flexibility for regional standards for roaming is needed. Nevertheless@ it was also recognized that a common world-wide radio interface and frequency band may increase the possibility of reduced costs of network and terminals and availability of equipment. The frequency allocations made by WARC-MOB-87 for the land mobile satellite service also influenced the study on FPLMTS@ with the realization of the opportunities that satellite links could bring to such systems. A number of objectives for FPLMTS has been agreed. It was found desirable to partition them into 19 primary ones and 10 secondary. The secondary status allows more freedom of choice for implementation. The FPLMTS could be considered as either an adjunct to or an integral part of the fixed network (PSTN/ISDN). The particular characteristics of the radio channel will@ however@ impose some constraints on the services offered as well as providing opportunities for others such as dispatch@ group call@ etc. Service should be provided to a variety of mobile terminals ranging from the PS to vehicle mounted mobile stations (MS). Additionally FPLMTS should be usable as a temporary or permanent substitute for the fixed network. The standards of services provided should be comparable with those of the fixed network@ and particular attention will have to be paid to the need for enhanced privacy/security on the radio channel (not only for speech@ but also for billing@ etc.). Two complementary scenarios are postulated. The first is concerned with land-based systems. This involves the PS operating in five modes@ i.e. accessing a private ""domestic"" base@ accessing a private office base@ accessing a public personal base@ accessing a public mobile base directly or communicating via an MS. The MS is linked to a base station (BS) for its mobile service and operates either in its own right or as a relay for a PS. The second scenario involves satellite links to mobile earth stations (MES) either in their own right or for relay to a PS. Also envisaged are satellite and terrestrial paging systems. An architecture is defined that shows interfaces within the FPLMTS and with the fixed network. The functionality of the mobile equipment is also indicated. The factors which affect the choice of desired frequency bands of operation are discussed. Starting with services to be offered and traffic models@ estimates are made of the requirements of such factors as modulation@ coding@ re-use@ etc.@ in order to assess the bandwidth requirement. This Report also contains comments on the choice of frequency bands including any biological-factors: The desire for compatibility within and between FPLMTS is commented on in several sections of the present Report as are the benefits of commonality. Considerations of compatibility with the ISDN give rise to the concept of mapping its B (bearer) and D (signalling) channels onto I (information) and C (control) channels for FPLMTS."