Digital cellular telecommunications system (Phase 2+); Network architecture (GSM 03.02 version 7.1.0 Release 1998) |
Copyright Notification No part may be reproduced except as authorized by written permission. © European Telecommunications Standards Institute 1998. All rights reserved. |
Contents
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Foreword
This ETSI Technical Specification (TS) has been produced by the Special Mobile Group (SMG) of the European Telecommunications Standards Institute (ETSI).
This TS present the possible architectures of the digital cellular telecommunications system (Phase 2/Phase 2+).
The contents of this TS are subject to continuing work within SMG and may change following formal SMG approval. Should SMG modify the contents of this TS it will then be republished by ETSI with an identifying change of release date and an increase in version number as follows:
Version 7.x.y
where:
7
indicates release 1998 of GSM Phase 2+;
x
the second digit is incremented for all other types of changes, i.e. technical enhancements, corrections, updates, etc.
y
the third digit is incremented when editorial only changes have been incorporated in the specification.
Introduction
The present document includes references to features which are not part of the Phase 2+ Release 96 of the GSM Technical specifications. All subclauses which were changed as a result of these features contain a marker (see table below) relevant to the particular feature.
The following table lists all features that were introduced after Release 96.
Feature |
Designator |
Shared Inter-Working Function |
$(SIWF)$ |
General Packet Radio Services |
$(GPRS)$ |
Location Services |
$(LCS)$ |
Scope
The purpose of this Technical Specification is to present the possible architectures of the mobile system. Clause 3 of this specification contains a definition of the different functional entities needed to support the mobile service. In clause 4, the configuration of a PLMN is described as well as the organisation of the functional entities; the configuration presented is the most general in order to cope with all the possible implementations which can be imagined in the different countries. To illustrate that purpose, some examples of possible configurations are presented. Clause 5 of this specification contains a brief description of the interfaces involved which shows the principle of the organisation considered.
1.1
Normative referencesReferences may be made to:
a)
specific versions of publications (identified by date of publication, edition number, version number, etc.), in which case, subsequent revisions to the referenced document do not apply; or
b)
all versions up to and including the identified version (identified by “up to and including” before the version identity); or
c)
all versions subsequent to and including the identified version (identified by “onwards” following the version identity); or
d)
publications without mention of a specific version, in which case the latest version applies.
A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number.
[1]
GSM 01.04: "Digital cellular telecommunications system (Phase 2+); Abbreviations and acronyms".
[2]
GSM 02.16: "Digital cellular telecommunications system (Phase 2+); International Mobile station Equipment Identities (IMEI)".
[2a]
GSM 02.60: “Digital cellular telecommunications system (Phase 2+); General Packet radio Service (GPRS); Service Description; Stage 1”.
[2b]
GSM02.71: “Digital cellular telecommunications system (Phase 2+); Location Services (LCS); Service Description; Stage 1”.
[3]
GSM 03.03: "Digital cellular telecommunications system (Phase 2+); Numbering, addressing and identification".
[4]
GSM 03.04: "Digital cellular telecommunications system (Phase 2+); Signalling requirements relating to routeing of calls to mobile subscribers".
[5]
GSM 03.08: "Digital cellular telecommunications system (Phase 2+); Organisation of subscriber data".
[6]
GSM 03.09: "Digital cellular telecommunications system (Phase 2+); Handover procedures".
[7]
GSM 03.12: "Digital cellular telecommunications system (Phase 2+); Location registration procedures".
[8]
GSM 03.20: "Digital cellular telecommunications system (Phase 2+); Security related network functions".
[9]
GSM 03.54: ”Digital cellular telecommunications system (Phase 2+); Description for the use of a Shared Inter Working Function (SIWF) in a GSM PLMN;
[9a]
GSM 03.60 “Digital cellular telecommunication system (Phase 2+); General Packet Radio Service (GPRS); Service Description; Stage 2”.
[10]
GSM 03.68 "Digital cellular telecommunications system (Phase 2+); Voice Group Call Service (VGCS) stage 2".
[10a]
GSM 03.64 “Digital cellular telecommunication system (Phase 2+); Overall
Description of the General Packet Radio Service (GPRS) Radio Interface; Stage 2”.
[10b]
GSM 03.71: “Digital cellular telecommunications system (Phase 2+); Location Services (LCS); Functional Description; Stage 2”.
[11]
GSM 03.89 "Digital cellular telecommunications system (Phase 2+); Voice Broadcast Service (VBS) stage 2".
[12]
GSM 04.02: "Digital cellular telecommunications system (Phase 2+); GSM Public Land Mobile Network (PLMN) access reference configuration".
[13]
GSM 08.01: "Digital cellular telecommunications system (Phase 2+); Base Station System - Mobile-services Switching Centre (BSS - MSC) interface
General aspects".
[14]
GSM 08.02: "Digital cellular telecommunications system (Phase 2+); Base Station System - Mobile-services Switching Centre (BSS - MSC) interface
Interface principles".
[15]
GSM 08.04: "Digital cellular telecommunications system (Phase 1); Base Station System - Mobile-services Switching Centre (BSS - MSC) interface Layer 1 specification".
[16]
GSM 08.06: "Digital cellular telecommunications system (Phase 2+); Signalling transport mechanism specification for the Base Station System - Mobile-services Switching Centre (BSS - MSC) interface".
[17]
GSM 08.08: "Digital cellular telecommunications system (Phase 2+); Mobile Switching Centre - Base Station System (MSC - BSS) interface
Layer 3 specification".
[18]
GSM 08.20: "Digital cellular telecommunications system (Phase 2+); Rate adaption on the Base Station System - Mobile-services Switching Centre (BSS - MSC) interface".
[19]
GSM 08.51: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface
General aspects".
[20]
GSM 08.52: "Digital cellular telecommunications system (Phase 2+); Base Station Controller - Base Transceiver Station (BSC - BTS) interface
Interface principles".
[21]
GSM 08.54: "Digital cellular telecommunications system (Phase 2+); Base Station Controller (BSC) to Base Transceiver Station (BTS) interface
Layer 1 structure of physical circuits".
[22]
GSM 08.56: "Digital cellular telecommunications system (Phase 2+); Base Station Controller (BSC) to Base Transceiver Station (BTS)
Layer 2 specification".
[23]
GSM 08.58: "Digital cellular telecommunications system (Phase 2+); Base Station Controller (BSC) to Base Transceiver Station (BTS) interface
Layer 3 specification".
[24]
GSM 08.60: "Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors".
[25]
GSM 08.61: "Digital cellular telecommunications system (Phase 2+); Inband control of remote transcoders and rate adaptors (half rate)"
[26]
GSM 09.02: "Digital cellular telecommunications system (Phase 2+); Mobile Application Part (MAP) specification".
[27]
GSM 09.03: "Digital cellular telecommunications system (Phase 2+); Signalling requirements on interworking between the Integrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN) and the Public Land Mobile Network (PLMN)".
[28]
GSM 09.04: "Digital cellular telecommunications system (Phase 2+); Interworking between the Public Land Mobile Network (PLMN) and the Circuit Switched Public Data Network (CSPDN)".
[29]
GSM 09.05: "Digital cellular telecommunications system (Phase 2+); Interworking between the Public Land Mobile Network (PLMN) and the Packet Switched Public Data Network (PSPDN) for Packet Assembly/Disassembly facility (PAD) access".
[30]
GSM 09.06: "Digital cellular telecommunications system (Phase 2+); Interworking between a Public Land Mobile Network (PLMN) and a Packet Switched Public Data Network/Integrated Services Digital Network (PSPDN/ISDN) for the support of packet switched data transmission services".
[31]
GSM 09.07: "Digital cellular telecommunications system (Phase 2+); General requirements on interworking between the Public Land Mobile Network (PLMN) and the Integrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN)".
[32]
GSM 09.10: "Digital cellular telecommunications system (Phase 2+); Information element mapping between Mobile Station - Base Station System and BSS ‑ Mobile-services Switching Centre (MS - BSS - MSC)
Signalling procedures and the Mobile Application Part (MAP)".
[33]
GSM 09.11: "Digital cellular telecommunications system (Phase 2+); Signalling interworking for supplementary services".
2
Definitions and abbreviations
In addition to the abbreviations given in the remainder of this clause others are listed in GSM 01.04.
2.1
Location registerTo enable communication to a mobile station the network must know where this mobile station is located. This information is stored in a function named location register.
2.1.1
Home Location Register (HLR)The Home Location Register (HLR)is the location register to which a mobile subscriber is assigned for record purposes such as subscriber information.
2.1.2
Visitor Location Register (VLR)The Visitor Location Register (VLR) is the location register, other than the HLR, used by an MSC to retrieve information for, e.g. handling of calls to or from a roaming mobile station currently located in its area.
2.1.3
Serving GPRS Support Node (SGSN) $(GPRS)$The location register function in the SGSN stores subscription information and location information for each subscriber registered in the SGSN.
The SGSN is needed only in a PLMN which supports GPRS.
2.1.4
Gateway GPRS Support Node (GGSN) $(GPRS)$The location register function in the GGSN stores subscription information and routeing information (needed to tunnel packet data traffic destined for a GPRS MS to the SGSN where the MS is registered) for each subscriber for which the GGSN has at least one PDP context active.
The GGSN is needed only in a PLMN which supports GPRS.
2.2
Authentication Centre (AuC)The Authentication Centre (AuC) is an entity which stores data for each mobile subscriber to allow the International Mobile Subscriber Identity (IMSI) to be authenticated and to allow communication over the radio path between the mobile station and the network to be ciphered. The AuC transmits the data needed for authentication and ciphering via the HLR to the VLR, MSC and SGSN which need to authenticate a mobile station.
The procedures used for authentication and ciphering are described more fully in GSM 03.20.
2.3
Equipment Identity Register (EIR)The Equipment Identity Register (EIR) in the GSM system is the logical entity which is responsible for storing in the network the International Mobile Equipment Identities (IMEIs), used in the GSM system.
The equipment is classified as "white listed", "grey listed", "black listed" or it may be unknown as specified in GSM 02.16 and GSM 09.02.
2.4
Mobile-services Switching Centre (MSC)The Mobile-services Switching Centre (MSC) constitutes the interface between the radio system and the fixed networks. The MSC performs all necessary functions in order to handle the calls to and from the mobile stations.
In order to obtain radio coverage of a given geographical area a number of base stations are normally required; i.e. each MSC would thus have to interface several base stations. In addition several MSCs may be required to cover a country.
2.5
Border Gateway (BG) $(GPRS)$The Border Gateway (BG) is a gateway between a PLMN supporting GPRS and an external inter-PLMN backbone network used to interconnect with other PLMNs also supporting GPRS. The role of the BG is to provide the appropriate level of security to protect the PLMN and its subscribers.
The BG is only needed in PLMNs supporting GPRS.
2.6
Public
Land
Mobile Network (PLMN)A Public Land Mobile Network (PLMN) is established and operated by an administration or Recognized Private Operating Agency (RPOA) for the specific purpose of providing land mobile telecommunications service services to the public. A PLMN may be regarded as an extension of a network (e.g. ISDN); it is a collection of MSCs areas within a common numbering plan (e.g. same National Destination Code) and a common routing plan. The MSCs are the functional interfaces between the fixed networks and a PLMN for call set-up.
Functionally the PLMNs may be regarded as independent telecommunications entities even though different PLMNs may be interconnected through the ISDN/PSTN and PDNs for forwarding of calls or network information. A similar type of interconnection may exist for the interaction between the MSCs of one PLMN.
2.7
CellThe cell is an area of radio coverage identified by a Base station identification as defined in GSM 03.03.
2.8
Base Station Controller (BSC) area The Base Station Controller (BSC) area is an area of radio coverage consisting of one or more cells controlled by one BSC. The boundaries of a BSC area and a location area are independent; a location area may span the boundary between BSC area and a BSC area may span the boundary between location areas.
2.9
Location Area (LA)The Location Area (LA) is defined as an area in which a mobile station may move freely without updating the VLR. A location area may include one or several cells.
2.10
Routing Area (RA) $(GPRS)$The Routing Area (RA) is defined as an area in which a mobile station, in certain operation modes, may move freely without updating the SGSN. A routing area may include one or several cells. A RA is always contained within a location area.
2.11
MSC areaThe MSC area is the part of the network covered by an MSC. An MSC area may consist of one or several location areas. An MSC area may also consist of one or several BSC areas.
2.12
GPRS Support Nodes (GSN) $(GPRS)$The GPRS support nodes, Gateway GSN (GGSN) and Serving GSN (SGSN) constitutes the interface between the radio system and the fixed networks for packet switched services. The GSN performs all necessary functions in order to handle the packet transmission to and from the mobile stations.
2.13
VLR areaThe VLR area is the part of the network controlled by a VLR. A VLR area may consist of one or several MSC areas.
2.14
SGSN area $(GPRS)$The SGSN area is the part of the network served by an SGSN. An SGSN area may consist of one or several routing areas. An SGSN area may also consist of one or several BSC areas. There need not be a one to one relationship between SGSN area and MSC/VLR area.
2.15
Zones for Regional SubscriptionA PLMN operator may define a number of regional subscription areas, each of which is a subset of the service area for an unrestricted mobile subscriber. A regional subscription area may be contained within the service area of a single PLMN, or may lie within the service areas of two or more PLMNs. Each regional subscription area consists of one or more zones; each zone is contained within the service area of a PLMN.
The definition of a mobile subscriber's regional subscription area is stored within the HLR per National Destination Code(s) (NDC) of a PLMN and is transferred to the VLRs and/or SGSNs of that PLMN. The VLR and/or SGSN evaluates this information to extract the restricted or accessible MSC and/or SGNS areas and location areas to which the mobile subscriber is allowed to roam. The VLR and/or SGNS informs the HLR if an entire MSC and/or SGNS area is restricted.
Zones for Regional Subscription and their handling are defined in GSM 03.03, GSM 03.08 and GSM 09.02.
2.16
Service areaThe service area is defined as an area in which a mobile subscriber can be reached by another (mobile or fixed) subscriber without the subscriber's knowledge of the actual location of the mobile station within the area. A service area may consist of several PLMNs. One service area may consist of one country, be a part of a country or include several countries. The location registration system associated with each service area must thus contain a list of all mobile stations located within that service area.
2.17
Group call areaThe group call area is a predefined area composed of one or a number of cells to which a particular Voice Group Call Service (VGCS) or Voice Broadcast Service (VBS) call is distributed. The composition of a group call area is predefined in the network. The group call area may include cells of more than one MSC area and cells of more than one PLMN.
2.18
Group Call Register (GCR)The Group Call Register (GCR) is a register holding information about VGCS or VBS calls, the voice group or broadcast call attributes, respectively.
Voice group or broadcast call attributes are defined for a specific voice group or broadcast call reference and include the data required to configure the conference bridge for a VGCS or VBS call and other call related attributes.
2.19 Serving
Mobile
Location
Center (SMLC) $(LCS)$The Serving Mobile Location Center (SMLC) node is responsible for managing the overall co-ordination and scheduling of resources required to perform positioning of a mobile, and calculating the final location estimate and accuracy.
There may be more than one SMLC in a PLMN.
Two types of SMLC are possible:
NSS based SMLC:
supports the Ls interface.
BSS based SMLC:
supports the Lb interface
An NSS based SMLC supports positioning of a target MS via signaling on the Ls interface to the visited MSC. A BSS based SMLC supports positioning via signaling on the Lb interface to the BSC serving the target MS. Both types of SMLC may support the Lp interface to enable access to information and resources owned by another SMLC.
The SMLC controls a number of LMUs for the purpose of obtaining radio interface measurements to locate or help locate MS subscribers in the area that it serves. The SMLC is administered with the capabilities and types of measurement produced by each of its LMUs. Signaling between an NSS based SMLC and LMU is transferred via the MSC serving the LMU using the Ls interface and either the Um interface for a Type A LMU or the Abis interface for a Type B LMU. Signaling between a BSS based SMLC and LMU is transferred via the BSC that serves or controls the LMU using the Lb interface and either the Um interface for a Type A LMU or the Abis interface for a Type B LMU.
For Location Services, when a Cell Broadcast Center (CBC) is associated with a BSC, the SMLC may interface to a CBC in order to broadcast assistance data using exis