1、RECOMMENDATION ITU-R M. 1308 EVOLUTION Of LAND MOBILE SYSTEMS TOWARDS IMT-2000 (Question -R 208/8) (1997) Summary This Recommendation provides information on the existing set of requirements and objectives specified in other ITU Recommendations for International Mobile Telecommunications-2000 (IMT-2
2、ooO). This Recommendation provides guidelines for developers of pre-IMT-2000 systems who intend to evolve their systems towards IMT-2000. The IT Radiocommunication Assembly, considering that Recommendations ITU-R M.1033 and ITU-R M.1073 summarize the characteristics of existing land a) mobile system
3、s, hereafter referred to as second generation systems, which potentially could evolve to IMT-2000; b) that the ITU-R is studying International Mobile Telecommunications-2000 (IMT-2000) (see Question ITU-R 39/8); c by, and specify the standards to be used in IMT-2000; d) that it could be advantageous
4、 for existing land mobile systems to evolve in the near future to include, anticipated or advanced services, facilities, or technologies identified in the Recommendations referred to in considering Cl; that various ITLJ Recommendations are being elaborated to describe the services and capabilities t
5、o be offered e) that enormous investment in pre-IMT-2000 networks will have taken place by the year 2000, and there is a need for as much commonality as possible between IMT-2000 and earlier systems in order to facilitate the evolution of pre-IMT-2000 systems; f) that there is a need to support term
6、inal roaming between pre-IMT-2000 and IMT-2000 systems; g) while also offering a whole new range of services and capabilities; that pre-IMT-2000 systems must address the primary customer demands of voice quality, coverage, and cost, h) different regions and at different times for different operators
7、; that evolution and migration may occur in discrete steps and these steps may occur at different times in j) that the evolution of systems and services can be independent of each other; k) that a universal user identity module (UIM) functionality should be used within all IMT-2000 systems; 1) commu
8、nication systems; that some of the .major objectives of IMT-2000 may be achieved by evolutions of existing mobile m) after the introduction of IMT-2000, that mass market needs may be supported by cellular-based pre-IMT-2000 systems for quite some time, even recommends 1 of pre-IMT-2000 systems; that
9、 the key features and global vision for IMT-2000 included in Annex 1, should be considered by developers COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services_ STD*ITU-R RECMN M.3308-ENGL 1997 = 48552I12 0532389 OT8 = Rec. ITU-R M.1308 87 2
10、 that the requirements and objectives summarized in Annex 2 and specified in the ITU Recommendations listed in Annex 3 should be incorporated into existing and emerging land mobile systems that intend to evolve towards IMT-2000; 3 systems to IMT-2000; that the standards for IMT-2000 be adopted as so
11、on as possible to support the timely evolution of existing 4 other widely used teleservices are not increased; that high bit-rate services should be provided in such a way that the cost of providing the speech service and 5 - maximize commonality with IMT-2OOO; - - support universal UIM functionalit
12、y. that pre-IMT-2000 systems intending to evolve towards IMT-2000 should: utilize the radio bearer adaptation functionality as discussed in Recommendation ITU-R M. 13 1 1 ; ANNEX 1 Key features and global vision for IMT-2000 1 Introduction IMT-2000 are third generation systems which aim to advance a
13、nd unify the diverse systems we see in the mid-1990s into a radio infrastructure capable of offering a wide range of services around the year 2000 in many different environments, including the wireless aspects of personal communications services. IMT-2000 will provide access, by means of one or more
14、 radio links, to a wide range of telecommunication services supported by the fixed telecommunications networks (e.g. public switched telephone networkhntegrated services digital network (PSTNASDN), and to other services which are specific to mobile users. A range of mobile terminal types is encompas
15、sed, linking to terrestrial or satellite-based networks, and the terminals may be designed for mobile or fixed use. Key features of IMT-2000 are: - - - high service quality, - worldwide seamless roaming, - high degree of commonality of design worldwide, compatibility of services within IMT-2000 and
16、with the fixed networks, use of a small pocket terminal worldwide. In order to maximize benefit from investment in mobile systems that are currently in service or will be introduced prior to IMT-2000 (these systems are referred to as pre-IMT-2000), it would be desirable to identify ways in which the
17、se systems can evolve towards IMT-2000. This would also ease the introduction of IMT-2000 itself and may enable a higher degree of reuse in the network infrastructure, system concepts, and/or technologies than would be possible otherwise. This issue is being considered on the basis that pre-IMT-2000
18、 systems may already possess some features and may undergo further development to enable an evolution path towards IMT-2000. It is also recognized that this approach may be most appropriate for those systems that operate in frequency bands close to the bands identified for IMT-2000. 2 Terminology an
19、d definitions The following terminology and definitions are provided for the purposes of this Recommendation. See Recommendation ITU-R M.1224 on Vocabulary of Terms for IMT-2000 for definition of IMT-2000 terminology in general. COPYRIGHT International Telecommunications Union/ITU Radiocommunication
20、sLicensed by Information Handling ServicesSTDDITU-R RECMN M-1308-ENGL 1997 4855212 0532190 81T 88 Rec. ITU-R M.1308 Compatibility A degree of transparency sufficient to support an acceptable grade of service with respect to a connection between system entities. Full compatibility implies full transp
21、arency (based on ITU-T Recommendation 4.300). Evolution A process of change and development of a mobile radio system towards enhanced capabilities. Evolution towards IMT-2000 A process of change and development of a mobile radio system towards the capabilities and functionaiities of IMT-2ooO. IMT-20
22、00 Those systems that conform to the corresponding series of ITU Recommendations and Radio Regulations. IMT-2000 radio interface (based on Recommendations IT-R M.1034 and ITU-R M.1224) The means of realizing the wireless electromagnetic interconnection between an IMT-2000 mobile station (or mobile e
23、arth station) and an IMT-2000 base station (or space station). Integration The act or process, or an instance, of forming, coordinating or blending into a functioning or unified whole. Interoperability The ability of multiple entities in different networks or systems to operate together without the
24、need for additional conversion or mapping of states and protocols. Interworking The means of supporting communications and interactions between entities in different networks or systems. Interworking functions (ITU-T Recommendation I. 113) Mechanisms which mask the differences in physical, link, and
25、 network technologies by converting or mapping states and protocols into consistent network and user services. Migration to IMT-2000 Movement of users and/or service delivery from existing telecommunication network to IMT-2000. Network A set of nodes and links that provides connections between two o
26、r more defined points to facilitate telecommunication between them (ITiJ-T Recommendations 1.1 12, Q.9). Network integration Integration as applied to networks. Path The continuous series of positions or configurations of a mobile radio system that can be assumed in the process of change when moving
27、 towardsan IMT-2000 system. Personal communications service A set of capabilities that allows some combination of terminal mobility, personal mobility, and service profile management. Pre-IMT-2000 Mobile systems that are currently in service or will be introduced prior to IMT-2000. COPYRIGHT Interna
28、tional Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling ServicesRadio interface protocol The protocol used across the radio interface (usually a collection of protocols supporting various layers of the protocol reference model). Service A set of functions offered to a
29、 user by an organization (I“U-T Recommendations E.800, M.60). System A regularly interacting or interdependent group of items forming a unified whole technology. System integration Integration as applied to systems. Technology A scientific method of achieving a practical purpose. User identity modul
30、e (UM) In IMT-2oo0, a logical entity which could be removable from a unit (mobile or fixed) or provided by functionality contained in a unit. It contains information elements needed by the system to identify, authenticate and permit the users registration. The UIM can also be used to store user spec
31、ific data. 3 Global IMT-2000 vision The following high-level global vision of IMT-2OOO contains a list of some of the key goals and objectives for IMT-2o00, based upon the market demands from a global perspective. It is expected that this vision may be expanded to include additional goals and object
32、ives as the work on IMT-2000 is progressed. 3.1 Quality of service 3.1.1 Voice quality, coverage, and cost Market studies have consistently shown that when customers are asked what things are important to them in their current wireless service, three issues arise: 1) voice quality, 2) coverage, 3) c
33、ost. Therefore, third generation systems must first address these primary customer demands, i.e. enable improved voice quality, support more ubiquitous and seamless coverage capabilities, and allow operators to offer services at a competitive price. 3.1.2 Quality of service aspects - Transmission an
34、d delay With the range of services expected, both the transmission quality and delay need to be adapted over a very wide range, together with the bandwidth and data rates. For mobile speech and video services, the maximum bit error ratio is usually specified at 1 x le3, while for data services, 1 x
35、le6 is required from the Radio Access system (RAS). These error rates for radio are significantly worse than those provided by fixed networks and so the speech coders or data adapters must provide the necessary user service quality. The delay requirement atulbuted to the Radio Access pari of todays
36、second generation systems is about 50 ms. Other parts of the system take the overall figure up to 90 ms (one way). In itself, for speech applications, this delay is unobtrusive, but compounded by other delays (tandem systems, satellite links, etc.) it can become a problem and so improvements are alw
37、ays desirable. For multimedia data services, there is likely to COPYRIGHT International Telecommunications Union/ITU RadiocommunicationsLicensed by Information Handling Services STDeITU-R RECMN flm3308-ENGL 3997 m 4855232 0532392 b92 m 90 Rec. ITU-R M.1308 be a huge variation in demanded delay, and
38、this will be an important aspect of service adaptation provided by operators in conjunction with adaptive terminals. Varying degrees of channel asymmetry may also be required. In order to allow much greater scope for mobile network operators to improve the perceived quality of their networks, this a
39、spect will be one of the main applications for the adaptive, software downloadable capability of IMT-2000 terminals. 3.1.3 Increased efficiency and capacity The clear trend is toward significant growth in the worldwide wireless subscriber base. Each wireless operator must prepare to meet this growth
40、. Third generation systems must, therefore, provide operators with economical and efficient means for providing service to their growing customer base. Any new systems must provide increases in network efficiencies as well as new services so that operators are motivated to deploy them. The challenge
41、 for third generation systems is to achieve better spectrum usage than any second generation system for voice communication and also to maintain optimum spectrum usage for all services at all times, despite their differing demands for data rates, symmetry, channel quality and delay. 3.2 New services
42、 and capabilities 3.2.1 Raising the bar Providing improvements in the three areas of voice quality, coverage and cost, while mandatory for third generation, will not be enough for the customers of the future. A rich range of services accessible in a variety of means will be needed to address the nee
43、ds of the customers after the year 2000. In effect, the services available from the next generation of systems must Raise The Bar in capabilities in every way, enabling new voice and data service that are not currently available with first and second generation technologies. 3.2.2 Increasing demand
44、for high bandwidth services (data, image, multimedia, etc.) The mobile office concept utilizing wireless notebooks on a wireless Wide Area Network will likely be a reality by the year 2000 and as such will require much more bandwidth than is possible today. Similarly, other wireless image transmissi
45、ons services are likely to be available, e.g. medical images for doctors, real-time road maps for vehicles, etc. Some administrations have already made considerable spectrum allocations in other bands to address the growing interest in high bandwidth packetized wireless data communications in the of
46、fice or classroom environments. Systems are envisioned which offer the possibility of very high bandwidths, at least for small area coverage systems, such as indoor or other high density applications such as sports stadiums, shopping malls etc. Important challenges are to provide means for integrati
47、ng and interworking between networks in other bands and IMT-2000, and to provide the technology at low cost. 3.2.3 Bandwidth on demand Third generation concepts impose the requirement to provide broadband services, interworking with broadband ISDN. This has been clarified to meh wireless access to t
48、he information highway for multimedia applications. Multimedia can address a huge range of data rates, from simple low rate paging messages, through voice to high rates associated with video or file transfer. Therefore the RAS should be capable of providing bandwidth on demand. Some applications, su
49、ch as software download, will require a highly asymmetrical data capability, requiring high rates in one direction, but much lower rates on the return path. Furthermore, some of these services require continuous transmission (such as desktop videoconferencing), some are bursty by nature, others require low delay and others require absolute integrity. The variable nature of the radio channel has already been mentioned; therefore the maximum throughput will be equally dynamic, requiring adaptive bandwidth from the RAS. COPYRIGHT International Telecommunications Union/ITU R
