1、INTERNATIONAL TELECOMMUNICATION UNION ITUIT TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Q.171 I SERIES Q: SWITCHING AND SIGNALLING Signalling requirements and protocols for IMT-2000 (03i99) Network functional model for IMT-2000 ITU-T Recommendation Q. 171 1 (Previously CCITT Recommendation) ITU-
2、T Q-SERIES RECOMMENDATIONS SWITCHING AND SIGNALLING SIGNALLING IN THE INTERNATIONAL MANUAL SERVICE INTERNATIONAL AUTOMATIC AND SEMI-AUTOMATIC WORKING FUNCTIONS AND INFORMATION FLOWS FOR SERVICES IN THE ISDN SPECIFICATIONS OF SIGNALLING SYSTEMS No. 4 AND No. 5 SPECIFICATIONS OF SIGNALLING SYSTEM No.
3、6 SPECIFICATIONS OF SIGNALLING SYSTEM RI SPECIFICATIONS OF SIGNALLING SYSTEM R2 DIGITAL EXCHANGES INTERWORKING OF SIGNALLING SYSTEMS CLAUSES APPLICABLE TO ITU-T STANDARD SYSTEMS , Q.1-Q.3 Q.4-Q.59 Q.60-Q.99 Q. 1 OO-Q. 1 I 9 Q.120-Q.249 Q.250-Q.309 Q.310-Q.399 Q.400-Q.499 Q.500-Q.599 Q.600-Q.699 SPEC
4、IFICATIONS OF SIGNALLING SYSTEM No. 7 DIGITAL SUBSCRIBER SIGNALLING SYSTEM No. 1 PUBLIC LAND MOBILE NETWORK Q. 700-Q ,849 Q.850-Q ,999 Q. 1000-Q. I O99 INTERWORKING WITH SATELLITE MOBILE SYSTEMS U INTELLIGENT NETWORK Q. 1 1 OO-Q. 1 1 99 Q. 1200-Q.1699 BROADBAND ISDN Q.2000-Q.2999 For further details
5、, please refir to ITU-T List of Recommendations. - - STD.ITU-T RECflN QeL7LL-ENGL 48b259L Obh405b 457 ITU-T RECOMMENDATION Q.1711 NETWORK FUNCTIONAL MODEL FOR IMT-2000 Summary This Recommendation identifies network and terminal functions that are specific for the support of IMT-2000 services, as spe
6、cified in the Recommendation on the Framework for IMT-2000 Networks (Recommendation Q, 170 i). These functions together with other, more conventional network functions are then grouped into functional entities in a generic functional model. In the functional model, the relationships among functional
7、 entities and groups are shown. The functional model is mapped onto a generic network reference model to illustrate possible groupings of functional entities into physical collections of entities. Based on the functional model, global roaming requirements and network interconnection scenarios are de
8、scribed. This Recommendation forms the basis for the development of information flows and the definition of functional entity actions and the development of signalling requirements for the various interfaces identified in Recommendation 4.1701. Source ITU-T Recommendation Q. 171 1 was prepared by IT
9、U-T Study Group 11 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 15th of March 1999. Keywords Functional architecture, Functional entity (FE), Global roaming, Handover, IMT-2000, Mobility management, Physical reference model, Virtual home environment (VHE) Recommendat
10、ion 4.1711 (03/99) 1 STD-ITU-T RECMN Q=L7LL-ENGL 1979 = 4Bb259L Ob64057 395 FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field 8f telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The
11、ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics fo
12、r study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the n
13、ecessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA an
14、d public correspondence are defined in the Constitution of the ITU (Geneva, 1992). INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no positio
15、n concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, prot
16、ected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1999 All rights reserved. No part of this publication may be rep
17、roduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. *. 11 Recommendation 4.1711 (03/99) CONTENTS 1 2 3 3.1 3.2 4 4.1 4.2 4.3 I 4.4 , I 4.5 4.6 4.7 4.8 4.9 Scope References Abbreviations and Defin
18、itions Abbreviations . Definitions IMT-2000 Specific Functions . Functions related to overall system access control., . Functions related to radio resource management and control 4.2.1 Synchronization control Functions related to access radio link control . Functions related to RF power control mana
19、gement Functions related to random access . Functions related to radio resource request acceptability . Functions related to channel coding . Functions related to handover Functions related to location management and b) to manage and maintain the access radio link after an end-to-end connection has
20、been established. (It may also be invoked to cater for in-call service modification or at handover execution.) Reservation and release of physical radio channels: This function consists of translating the access radio link Set-up or release requests into physical radio channel requests, reserving or
21、 releasing the corresponding physical radio channels and acknowledging this reservatiodrelease to the requesting entity. Acceptability of such physical radio channel requests is determined by the Radio resource request acceptability judgement function. This function may also perform physical channel
22、 reservation and release in the case of a handover. Moreover, the amount of radio resource required may change during a call, due to service requests from the user or macro-diversity requests. Therefore, this function must also be capable of dynamically reserving or releasing physical channels durin
23、g a call. Allocation and de-allocation of physical radio channels: This function is responsible, once physical radio channels have been reserved, for actual physical radio channel usage, allocating or de- allocating the corresponding physical radio channels for information transfer. Packet data tran
24、sfer over radio function: This function provides packet data transfer capability across the IMT-2000 radio interface. This function includes procedures which: a) b) 4 d) e) provide flow control procedures; 0 Functions related to access radio link control provide packet access control over radio chan
25、nels; provide packet multiplexing over common physical radio channels; provide packet discrimination within the mobile terminal; provide error detection and correction; provide load balancing across RF channels. 4.2.3 RF power control: In order to minimise the level of interference (and thereby maxi
26、mise the re-use of radio spectrum), it is important that the radio transmission power is not higher than what is required for the requested service quality. Based on assessments of radio channel quality, this Functions related to RF power control management Recommendation Q.1711 (03/99) 9 STD-ITU-T
27、RECMN Q-L?LL-ENGL 1999 m 48b2591 Obb4070 829 = function controls the level of the transmitted power from the mobile terminal as well as the base station. RF power setting: This function adjusts the output power of a radio transmitter according to control information from the RFpower control function
28、. The function forms an inherent part of any power control scheme, whether closed or open loop. 4.2.4 Random access initiation: This function is used by a mobile terminal when it accesses the network. Due to the multiple access nature of the radio interface (many mobile terminals attempting to acces
29、s common resources in an independent and random way), a specific random access procedure may have to be used when the mobile terminal accesses the network for the setting up of a connection or other applications. This function will start this procedure when required. Random access detection and hand
30、ling: This function in the network detects the random access initiation attempt by the mobile terminal and responds appropriately. The handling of the random access may include procedures for a possible resolution of colliding attempts, etc. The successful result will be the generation of a request
31、for allocation of appropriate resources for the requesting mobile terminal. Functions related to random access 4.2.5 Radio resource request acceptability information setting: This function sets and updates the information on possibility of radio resource allocation based on the radio resource availa
32、bility in a cell. This information is used by the Radio resource request acceptability judgement function. Radio resource request acceptability information broadcasting: This function broadcasts, in a cell, the radio resource request acceptability information obtained from the Radio resource request
33、 acceptability information setting function. Radio resource request acceptability judgement: This function can be implemented in the network as well as in mobile terminals. In the network, this function judges the possibility of radio resource allocation upon each request of such a resource based on
34、 the radio resource request acceptability information obtained from the Radio resource request acceptability information setting function. In the mobile terminal, this function judges the radio resource request acceptability information broadcast by the Radio resource request acceptability informati
35、on broadcasting function. Based on the result, this function permits the initiation of service request from the mobile terminal which requires radio resources (e.g. call origination) only when positive result is obtained from the judgement. Functions related to radio resource request acceptability 4
36、.3 Radio channel source and error protection coding and decoding: This function is to protect data from transmission errors on the radio channels by attached specific coding. Major coding schemes include: a b) c) The coding is performed independently of the content or meaning of the data. Functions
37、related to channel coding Convolutional code which is used for both error detecting and correcting; Cyclic Redundancy Check which is used only for error detecting; Interleave which is used for error protecting. 10 Recommendation Q.1711 (03/99) STD-ITU-T RECMN Q=L7LL-ENGL L999 4862591 066407L 765 4.4
38、 Functions related to handover Radio channel quality estimation: This function performs measurements on radio channels (current and surrounding cells) and translates these measurements into radio channel quality estimates. Measurements may include: a b) estimated bit error ratios; c d) e Doppler spr
39、ead; f, synchronization status. In order for these measurements and the subsequent analysis to be meaningful, some association between the measurements and the channels to which they relate should be made in the analysis. Such association may include the use of identifiers for the network, the base
40、station, the cell (base station sector) and/or the radio channel. Cell selection in dedicated mode: When a mobile terminal is engaged in a circuit-switched connection, it is in dedicated mode. When a mobile terminal is in dedicated mode, it may additionally be engaged in a packet data transaction. T
41、he Cell selection in dedicated mode function enables the mobile terminal to select the preferred cell to which a circuit-switched connection may be accessed or handed over. The cell is selected from a candidate list which the network sends to the mobile terminal. The function involves the measuremen
42、t and evaluation of signal quality from neighbouring cells, as well as the detection and avoidance of congestion within candidate cells to which access or handover may be requested. Quality of service assessment: This function assesses the overall quality of service. This may take into account radio
43、 channel quality estimates (including estimates from surrounding cells), packet throughput, delay, and other quality of service metrics. The overall quality of service is compared with requested limits and with estimates from surrounding cells. Depending on the outcome of this comparison, the Resour
44、ce re-allocation function, the Macro-diversity control function or the Handover execution function may be activated. Resource reallocation: A network always monitors the status of how the resources are used. When a network detects the insufficiency of available resources, it may perform inter or int
45、ra cell handover sequence, or reallocation of other resources being used in order to get different available resources. Handover decision - received signal strengths (current and surrounding cells); estimation of propagation environments (e.g. high-speed, low-speed, satellite, etc.); transmission ra
46、nge (e.g. through timing information); initiated by the terminal: This function results from the Quality of service assessment function and generates a request for new resources. In this case the terminal uses a resource reallocation or handover strategy to select new resources. When required, it ma
47、y also request that the network combine the diversity paths. initiated by the network: This function results from the Quality of service assessment function or the Resource reallocation function and generates a request for different resources. In this case the network uses a resource reallocation or
48、 handover strategy to select new resources and coordinates assignment of the new resource. When required, it may also request that the terminal combine the diversity paths. Macro-diversity control: Upon request from the Handover decision function or the Quality of service assessment function, this f
49、unction controls the duplicatiodreplication of information streams to receive/transmit the same information through multiple physical radio channels (possibly in different cells) from/towards a single mobile terminal. - Recommendation 4.171 1 (03/99) 11 This function also controls the combining of information streams generated by a single source, but conveyed via several diversity sub-links. The Mucro diversity control function controls macro- diversity execution (i.e. distribution and combination of the information stream) which is located at the two endpoints of the connec
