1、160 1 2 3 4 5 6 7 8 9 10 Rec. ITU-R M.1311 RECOMMENDATION ITU-R M. 13 1 1 FRAMEWORK FOR MODULARITY AND RADIO COMMONALITY WITHIN LMT-2000 (1997) CONTENTS Introduction 1.1 Emerging trends 1.2 1.3 Rationale Scope Related documents Terminology 4.1 Terms and definitions 4.2 Acronyms and abbreviations Rec
2、ommendations Approach to modularity RAN modelling 7.1 Basic IMT-2000 model 7.2 Pre-IMT-2000 systems Objectives of IMT-2000 that impact on modularity 7.2.1 Evolving towards IMT-2000 capabilities 7.2.2 7.2.3 Interworking with IMT-2000 networks Adaptation functionality with IMT-2000 networks 7.3 Satell
3、ite aspects Commonality in packet access mechanisms Identification of common functions in RBCF 9.1 9.2 Common functions in RBCF Guidelines for assessing whether a function can be made common 9.2.1 Radio transport functions 9.2.1.1 Error detection and correction 9.2.1.2 Frames structure adaptation 9.
4、2.1.3 Multiplexing and demultiplexing 9.2.1.4 Source coding 9.2.1.5 Encryption and decryption 9.2.2 Radio resources management functions 9.2.2.1 9.2.2.2 Flexible resource allocation 9.2.2.3 Multibearer capability 9.2.2.4 Admission control 9.2.2.5 Quality control 9.2.3 Mobility-related functions 9.2.
5、3.1 Handover 9.2.3.2 Macrodiversity 9.2.3.3 Paging execution Bearer capacity set up and release Summary and conclusions Annex 1 - ATM service modes of operation Annex 2 -Mobile multimedia services STD=ITU-R RECMN M.33LL-ENGL 3997 m 4855232 0532453 b95 m Rec. ITU-R M.1311 161 1 Introduction Internati
6、onal Mobile Telecomunications-2000 (IMT-2000) are third generation mobile systems which are scheduled to start service around the year 2000 subject to market considerations. They will provide access, by means of one or more radio links, to a wide range of telecommunication services supported by the
7、fixed telecommunication networks (e.g. public switched telephone networklintegrated services digital network (PSTNASDN), and to other services which are specific to mobile users. A range of mobile terminal types is encompassed, linked to terrestrial and/or satellite-based networks, and the terminais
8、 may be designed for mobile or fixed use. Key features of IMT-2ooO are: - - - high service quality, - worldwide roaming, and - high degree of commonality of design worldwide, compatibility of services within IMT-2000 and with the fixed networks, use of a small pocket terminal worldwide. This Recomme
9、ndation forms part of the process of specifying the radio interface(s) of IMT-2000. IMT-2000 is defined by a set of interdependent Recommendations of which this Recommendation is a member. 1.1 Emerging trends One of the most challenging aspects of designing future wireless telecommunications systems
10、 is accurately anticipating what the future market and technological drivers will be. This is made even more difficult by the rapid advances in technology over the last few years and the increasingly sophisticated demands of the end-user. For example, in the next few years wireless networks will lik
11、ely need to support high-speed data, image, andor multimedia in addition to pure voice traffic in order to meet customer demands. Even voice will be coded differently and at different rates for various services and applications. This will create the need for an infrastructure that can support end-us
12、er connections with differing technical systems requirements. As a result of all the factors, the design of any future wireless network must be as flexible as possible. Clearly, a common, flexible infrastructure is needed that can interface with multiple radio interface technologies on the one hand
13、and multiple fixed network technologies on the other. At the time IMT-2000 are introduced, narrow-band voice networks will still predominate in the fixed network, but advanced broadband networks will be a critical component as well. In these broadband networks, asynchronous transfer mode (ATM) techn
14、ology will likely be the switching and transmission technology of choice due to the provision of a common, flexible platform from which many different types of communications (voice, data, image, video, high-quality sound and multimedia) can be served. In addition, there is a worldwide move towards
15、standards which are substantially technology-independent, to maximize their potential application to a number of different environments. A number of emerging trends are having a significant impact upon the design of telecommunications networks and current indications are that this process will accel
16、erate in the future. Work in other standards bodies, particularly regarding broadband technologies, and other major advances in technology, are contributing to this situation. Of particular consequence to network design are: - - - - - - the separation of applications from networks, the convergence o
17、f telecommunications and information technology, the convergence of fixed, mobile and private network capabilities, the emerging importance of personal communications, new advanced distributed processing concepts available for service control, the increasing use of ATM and transmission control proto
18、coVInternet protocol (TCPAP) for the transport of all types of information, the need for substantially “seamless” evolution from one telecommunications technology/standard to a later one, or for evolution within the standard. - STD=ITU-R RECMN M.1311-ENGL 3777 4855232 0532454 521 = 162 Rec. ITU-R M.
19、1311 1.2 Objectives of IMT-2000 that impact on modularity Important design objectives for IMT-2000 are to minimize the number of radio interfaces, to maximize the commonality between them and to be able to flexibly adapt different services onto these radio interface). These design objectives should
20、be met in order to minimize costs and to ease service and network deployment. A number of objectives have been established which place requirements upon IMT-2000 system design and the design of networks implementing IMT-2000. The key aspects for the purpose of this Recommendation are: - to facilitat
21、e evolution to IMT-2000 from existing fixed and mobile systems; - - to provide a common platfodframework for the support of various categories of services; to be adaptable to the service providers and network operators need to differentiate their service offerings; - to facilitate the deployment of
22、the system in a manner consistent with the individual needs of service providers and network operators. Each of these objectives could have a significant impact upon IMT-2000 system, network and protocol design. In short, two major goals to be achieved for the transport mechanisms are: independence
23、from the transmission technology and support of a wide and changing range of services. A modularized functional and physical architecture needs to satisfy the following requirements: - future evolution, - interworking between a variety of access technologies/standards, core transport and core contro
24、l standardshetworks, - technology-independence of telecommunications standards, - - - - backwards compatibility. service differentiation options for operators andor service providers, standards which provide scope, within a generic framework, for proprietary enhancements to meet specific needs, supp
25、ort for a variety of radio environments, 1.3 Rationale IMT-2000 will serve different radio environments leading potentially to different radio interface technology choices. In order to minimize the investments in the core network (CN), it is thought that the ability to connect different radio transm
26、ission modules to the same CN equipment, e.g. a switch, should be investigated. Moreover, it has been recognized that IMT-2000 shall be “future proof, that is IMT-2000 shall have the ability to evolve by replacing modules and keeping others. Such a design will also facilitate the evolution of mobile
27、 systems that are currently in service or will be introduced prior to IMT-2000 (referred to as “pre-IMT-2000” systems) to third generation ones. One way to achieve such a goal is, again, to have radio transmission modules clearly separated from the CN. Such similar goals have been pursued in the fie
28、ld of the fixed network and led to the development of ATM standards. Therefore it is proposed to adopt a similar approach for the radio interface of IMT-2000. Taking a similar approach means using a layered approach leading to a clear independence of the transport mechanism from the services on one
29、side and from the transmission technology on the other side. 2 Scope This Recommendation is primarily based on the principles, requirements and framework of the IMT-2000 radio interface(s), as outlined in IMT-2000 Recommendations IT-R M.687, ITU-R M.819, IT-R M.1034 and IT-R M. 1035. This Recommenda
30、tion identifies and describes the modularity and radio commonality principles which should be adopted in the development of the radio-related aspects of IMT-2000. STDmITU-R RECMN M-LLII-ENGL I1997 m 4855232 0532455 Yb8 m Rec. ITU-R M.1311 163 This includes: - - - The purpose of the Recommendation is
31、 to facilitate the development of a modular framework which can be used as a basis for specific architectures, enabling these to be combined in various ways to meet operators needs. the modularity concept and its rationale, the functional modules in the radio access network (RAN), the groupings of f
32、unctions in the RAN. 3 Related documents - Recommendation ITU-R M.687: - Recommendation ITU-R M.8 16: - Recommendation ITU-R M.817: - Recommendation ITU-R M.818: - Recommendation ITU-R M.819: - Recommendation ITU-R M. 1034: - Recommendation ITU-R M. 1035: - Recommendation ITU-R M.1036: - Recommendat
33、ion ITU-R M. 1 167: - Recommendation ITU-R M.1224: - Recommendation ITU-R M.1225: - ITU-T Recommendation 4.93 1: - ITU-T Recommendation 4.2931 : 4 Terminology This paragraph defines terminology tion ITU-R M.1224. International Mobile Telecommunications-2000 (IMT-2000). Framework for services support
34、ed on IMT-2000. Intemational Mobile Telecommunications-2000 (IMT-2000) Network Architectures. Satellite operations within IMT-2000. IMT-2000 for Developing Countries. Requirements for the Radio Interface(s) for IMT-2000. Framework for the Radio Interface(s) and Radio Subsystem Functionality for IMT-
35、2000. Spectrum Considerations for Implementation of IMT-2000 in the Bands 1 885-2 025 MHz and 2 1 10-2 200 MHz. Framework for the Satellite Component of IMT-2000. Vocabulary of Terms for IMT-2000. Guidelines for Evaluation of Radio Transmission Technologies for IMT-2000. Digital subscriber signallin
36、g system No. 1 (DSS 1) - ISDN user-network interface layer 3 specification for basic call control. Broadband integrated services digital network (B-ISDN) - Digital Subscriber Signalling System No. 2 (DSS 2) - User-Network Interface (UNI) layer 3 specification for basic calikonnection control. releva
37、nt to this Recommendation which is not included in Recommenda- 4.1 Terms and definitions Adaptation functionality (AF) A set of functions which allows the provision of CN services transparently through the RAN between the mobile terminal and the corresponding CN. Interworking function (IWF) Mechanis
38、m which masks the differences in physical, link and network technologies by converting or mapping states and protocols into consistent network and user services (see Recommendation ITU-R M. 1224). STDmITU-R RECflN M.L3LL-ENGL 1997 m 4855212 0532456 3T4 m 164 Rec. ITU-R M.1311 Mobile terminal other f
39、unctionality (MTF) The set of functions which, together with the MT-RTT, form a mobile terminai. Radio access network (RAN) A network which provides the connectivity between the mobile terminal and the CN and typically consists of a network of base stations and associated controllers. Radio bearer c
40、ommon functionality (RBCF) A common adaptation functionality situated between the R4N interface and the RTAFs. RBCF adapts respective RT/RTAF combinations onto the RAN interface. RBCF principally contains radio technology independent functions. Radio transmission adaptation functionality (RTAF) A fu
41、nctionality which provides the necessary functions to adapt a specific RTT with the RBCF. In contrast to the RBCF, the RTAF is radio transmission technology dependent and RTAFs adapt different RTTs to the RBCF. Radio transmission specific functionality (RTSF) A functionality which is explicitly radi
42、o technology and radio operating environment dependent. In the RAN, the RTSF includes all the functions related to RAN-RTT and RTAF. 4.2 Acronyms and abbreviations AF: Adaptation functionality CN: Core network DSS 2: IWF: Interworking function MPEG 4: Moving picture expert group 4 MTF: Mobile termin
43、al other functionality RAN: Radio access network RBCF: Radio bearer common functionality RTAF: Radio transmission adaptation functionality RTSF: Radio transmission specific functionality RTT: Radio transmission technology TCPAP: Transmission control protocoVInternet protocol Digital subscriber signa
44、lling system 2 5 Recommendations The ITU Radiocommunication Assembly recommends that the framework for modularity and radio commonality presented in the following should be adopted for IMT-2000. 6 Approach to modularity The recommended approach.to modularity is based on the separation of transport,
45、access, control and management functionalities within systems. A system is defined as being a regularly interacting or interdependent group of items forming a unified, whole technology (see Recommendation ITU-R M. 1224). Systems should be decomposed into a number of subsystems, each consisting of re
46、sources and functionality wholly controlled by that subsystem. Subsystem boundaries should be clearly delineated and specified, with each subsystem providing its own specific capabilities to one or more other subsystems and able to use the capabilities of other subsystems. Subsystems can be enhanced
47、 to provide additional capabilities without affecting any other subsystem. Individual subsystem enhancements can be implemented and deployed in any order, to facilitate system upgrading and network Rec. ITU-R M.1311 165 /2/ operation and evolution. Here, the network is defined as a set of nodes and
48、links that provides connections between two or more defined points to facilitate telecommunication between them (see Recommendation -R M. 1224). Intelligence RAN Transport Similarly, entirely new subsystems can be added to take care of evolving needs without adversely affecting the other subsystems.
49、 The interfaces between the different sub-networks need to be clearly defined and delineated, so that it is possible to introduce or enhance a new sub-network without causing problems in another network. Ideally the interfaces between the different sub-networks should be radio-technology independent, such that any suitable technology can be used. The modular subsystem or network approach facilitates system and network evolution. Each module (subsystem or network) should be plug-compatible, in the sense that each network can substitute replacement modules without impacting o
