3GPP TS 23.122 V7.0.0 (2005-01)
`
`Technical Specification
`
`3rd Generation Partnership Project;
`Technical Specification Group Core Network;
`NAS Functions related to Mobile Station (MS) in idle mode
`(Release 7)
`
`The present document has been developed within the 3rd Generation Partnership Project (3GPP TM) and may be further elaborated for the purposes of 3GPP.
`
`The present document has not been subject to any approval process by the 3GPP Organisational Partners and shall not be implemented.
`
`This Specification is provided for future development work within 3GPP only. The Organisational Partners accept no liability for any use of this Specification.
`Specifications and reports for implementation of the 3GPP TM system should be obtained via the 3GPP Organisational Partners' Publications Offices.
`
`3G Exhibit 2006
`IPR2020-01157
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`3GPP TS 23.122 V7.0.0 (2005-01)
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`Keywords
`UMTS, network, terminal
`
`3GPP
`
`Postal address
`
`
`3GPP support office address
`650 Route des Lucioles - Sophia Antipolis
`Valbonne - FRANCE
`Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16
`
`Internet
`http://www.3gpp.org
`
`Copyright Notification
`
`No part may be reproduced except as authorized by written permission.
`The copyright and the foregoing restriction extend to reproduction in all media.
`
`© 2005, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC).
`All rights reserved.
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`3GPP
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`3GPP TS 23.122 V7.0.0 (2005-01)
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`Contents
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`Foreword............................................................................................................................................................. 4
`
`1
`1.1
`1.2
`
`2
`
`Scope ........................................................................................................................................................ 5
`References.......................................................................................................................................................... 5
`Definitions and abbreviations ............................................................................................................................ 6
`
`General description of idle mode ............................................................................................................. 8
`
`3
`3.1
`3.2
`3.3
`3.4
`3.4.1
`3.4.2
`3.5
`3.6
`
`Requirements and technical solutions ...................................................................................................... 9
`PLMN selection and roaming ............................................................................................................................ 9
`Regional provision of service .......................................................................................................................... 10
`Borders between registration areas .................................................................................................................. 10
`Access control .................................................................................................................................................. 10
`Access control ............................................................................................................................................ 10
`Forbidden LA for regional provision of service ......................................................................................... 10
`No suitable cell (limited service state) ............................................................................................................. 10
`CTS fixed part selection (A/Gb mode only) .................................................................................................... 11
`
`4
`4.1
`4.2
`4.3
`4.3.1
`4.3.1.1
`4.3.1.2
`4.3.2
`4.3.3
`4.4
`4.4.1
`4.4.2
`4.4.3
`4.4.3.1
`4.4.3.1.1
`4.4.3.1.2
`4.4.3.2
`4.4.3.2.1
`4.4.3.2.2
`4.4.3.3
`4.4.3.4
`4.4.4
`4.4.5
`4.5
`4.5.1
`4.5.2
`4.5.3
`4.5.4
`4.5.5
`4.6
`4.7
`4.8
`
`Overall process structure ........................................................................................................................ 11
`Process goal ..................................................................................................................................................... 11
`States description ............................................................................................................................................. 11
`List of states ..................................................................................................................................................... 11
`List of states for the PLMN selection process ............................................................................................ 11
`List of states for automatic mode (figure 2a) ........................................................................................ 11
`List of states for manual mode (figure 2b) ........................................................................................... 12
`List of states for location updating (figure 3) ............................................................................................. 12
`List of states for location registration (figure 3) ......................................................................................... 12
`PLMN selection process .................................................................................................................................. 13
`Introduction ................................................................................................................................................ 13
`Registration on a PLMN ............................................................................................................................ 13
`PLMN selection ......................................................................................................................................... 13
`At switch-on or recovery from lack of coverage .................................................................................. 14
`Automatic Network Selection Mode Procedure .............................................................................. 14
`Manual Network Selection Mode Procedure .................................................................................. 15
`User reselection .................................................................................................................................... 16
`Automatic Network Selection Mode ............................................................................................... 16
`Manual Network Selection Mode ................................................................................................... 17
`In VPLMN ............................................................................................................................................ 17
`Investigation Scan for higher prioritized PLMN .................................................................................. 18
`Abnormal cases .......................................................................................................................................... 18
`Roaming not allowed in this LA ................................................................................................................ 18
`Location registration process ........................................................................................................................... 18
`General ....................................................................................................................................................... 18
`Initiation of Location Registration ............................................................................................................. 19
`Periodic Location Registration ................................................................................................................... 20
`IMSI attach/detach operation ..................................................................................................................... 20
`No Suitable Cells In Location Area ........................................................................................................... 20
`Service indication (A/Gb mode only) .............................................................................................................. 21
`Pageability of the mobile subscriber ................................................................................................................ 21
`MM Restart Procedure ..................................................................................................................................... 21
`
`5
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`Tables and Figures ................................................................................................................................. 22
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`Annex A (normative):
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`HPLMN Matching Criteria .......................................................................... 28
`
`Annex B (normative):
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` PLMN matching criteria to be of same country as VPLMN .................... 32
`
`Annex C (informative):
`
`
`Change history ............................................................................................... 33
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`3GPP TS 23.122 V7.0.0 (2005-01)
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`Foreword
`
`This Technical Specification (TS) has been produced by the 3rd Generation Partnership Project (3GPP).
`
`The present document specifies functions related to Mobile Station (MS) in idle mode and within the 3GPP system.
`
`The contents of the present document are subject to continuing work within the TSG and may change following formal
`TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
`identifying change of release date and an increase in version number as follows:
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`Version x.y.z
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`where:
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`x
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`the first digit:
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`1 presented to TSG for information;
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`2 presented to TSG for approval;
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`3 or greater indicates TSG approved document under change control.
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`y
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`the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
`updates, etc.
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`z
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`the third digit is incremented when editorial only changes have been incorporated in the document.
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`1
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`Scope
`
`The present document gives an overview of the tasks undertaken by the Core network protocols of a Mobile Station
`(MS) when in idle mode, that is, switched on but typically not having a dedicated channel allocated. It also describes the
`corresponding network functions. The idle mode functions are also performed by a GPRS MS as long as no dedicated
`channel is allocated to the MS. The conditions when the idle mode functions are performed by an MS in the UTRA
`RRC connected mode states are specified in TS 25.331.
`
`This 3GPP TS outlines how the requirements of the 22 series Technical Specifications (especially 3GPP TS 22.011) on
`idle mode operation shall be implemented. Further details are given in 3GPP TS 24.008.
`
`Clause 2 of this 3GPP TS gives a general description of the idle mode process. Clause 3 outlines the main requirements
`and technical solutions of those requirements. Clause 4 describes the processes used in idle mode. There is inevitably
`some overlap between these clauses.
`
`1.1
`
`References
`
`The following documents contain provisions which, through reference in this text, constitute provisions of the present
`document.
`
`- References are either specific (identified by date of publication, edition number, version number, etc.) or
`non-specific.
`
`- For a specific reference, subsequent revisions do not apply.
`
`- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
`a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
`Release as the present document.
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`[1]
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`[2]
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`[3]
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`[4]
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`[5]
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`[6]
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`[7]
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`[8]
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`[9]
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`[10]
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`[11]
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`[12]
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`[13]
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`[14]
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`[15]
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`[16]
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`Void.
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`3GPP TS 22.001: "Principles of circuit telecommunication services supported by a Public Land
`Mobile Network (PLMN)".
`
`3GPP TS 22.002: "Circuit Bearer Services (BS) supported by a Public Land Mobile Network
`(PLMN)".
`
`3GPP TS 22.003: "Circuit Teleservices supported by a Public Land Mobile Network (PLMN)".
`
`3GPP TS 22.004: "General on supplementary services".
`
`Void.
`
`Void
`
`Void.
`
`3GPP TS 22.011: "Service accessibility".
`
`3GPP TS 22.016: "International Mobile station Equipment Identities (IMEI)".
`
`Void.
`
`3GPP TS 22.024: "Description of Charge Advice Information (CAI)".
`
`3GPP TS 22.030: "Man-Machine Interface (MMI) of the User Equipment (UE)".
`
`Void.
`
`3GPP TS 22.041: "Operator Determined Barring (ODB)".
`
`3GPP TS 22.081: "Line identification Supplementary Services; Stage 1".
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`[17]
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`[18]
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`[19]
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`[20]
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`[21]
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`[22]
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`[23]
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`[24]
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`[25]
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`[26]
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`[27]
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`[28]
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`[29]
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`[30]
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`[31]
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`[32]
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`[33]
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`[34]
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`[35]
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`[36]
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`[37]
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`[38]
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`[39]
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`[40]
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`3GPP TS 22.082: "Call Forwarding (CF) supplementary services - Stage 1".
`
`3GPP TS 22.083: "Call Waiting (CW) and Call Holding (HOLD); Supplementary Services -
`Stage 1".
`
`3GPP TS 22.084: "MultiParty (MPTY) Supplementary Services - Stage 1".
`
`3GPP TS 22.085: "Closed User Group (CUG) Supplementary Services - Stage 1".
`
`3GPP TS 22.086: "Advice of Charge (AoC) Supplementary Services - Stage 1".
`
`3GPP TS 22.088: "Call Barring (CB) Supplementary Services - Stage 1".
`
`3GPP TS 24.008: "Mobile Radio Interface Layer 3 specification, Core Network Protocols -
`Stage 3".
`
`3GPP TS 45.002: "Multiplexing and multiple access on the radio path".
`
`3GPP TS 45.008: "Radio subsystem link control".
`
`3GPP TS 22.060: "General Packet Radio Service (GPRS); Service description, Stage 1".
`
`3GPP TS 23.060: "General Packet Radio Service (GPRS); Service description;Stage 2".
`
`3GPP TS 43.064: "General Packet Radio Service (GPRS); Overall description of the GPRS Radio
`Interface; Stage 2".
`
`Void.
`
`Void.
`
`3GPP TS 25.101: "UE Radio transmission and Reception (FDD)".
`
`3GPP TS 25.304: "UE Procedures in Idle Mode and Procedures for Cell Reselection in Connected
`Mode".
`
`3GPP TS 25.331: "RRC Protocol Specification".
`
`3GPP TS 44.018:"Mobile radio interface layer 3 specification, Radio Resource Control Protocol".
`
`3GPP TS 43.022: "Functions related to Mobile Station (MS) in idle mode and group receive
`mode".
`
`3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
`
`Void.
`
`3GPP TS 21.111: "USIM and IC card requirements".
`
`3GPP TS 44.060: "General Packet Radio Service (GPRS);Mobile Station (MS) - Base Station
`System (BSS) interface;Radio Link Control/Medium Access Control (RLC/MAC) protocol".
`
`3GPP TS 31.102: "Characteristics of the USIM Application".
`
`1.2
`
`Definitions and abbreviations
`
`For the purposes of the present document, the abbreviations defined in 3GPP TR 21.905 [36] apply.
`
`(A/Gb mode only): Indicates this clause applies only to GSM system. For multi system case this is determined by the
`current serving radio access network.
`
`(Iu mode only): Indicates this clause applies only to UMTS system. For multi system case this is determined by the
`current serving radio access network.
`
`Acceptable Cell: This is a cell that the MS may camp on to make emergency calls. It must satisfy criteria which is
`defined for A/Gb mode in 3GPP TS 43.022 and for Iu mode in 3GPP TS 25.304.
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`Access Technology: The access technology associated with a PLMN. The MS uses this information to determine what
`type of radio carrier to search for when attempting to select a specific PLMN (e.g., GSM, UMTS or GSM COMPACT).
`A PLMN may support more than one access technology.
`
`Allowable PLMN: In the case of a MS operating in MS operation mode A or B, this is a PLMN which is not in the list
`of "forbidden PLMNs" in the MS. In the case of a MS operating in MS operation mode C, this is a PLMN which is not
`in the list of "forbidden PLMNs" or in the list of "forbidden PLMNs for GPRS service" in the MS
`
`Available PLMN: For GERAN A/Gb mode see 3GPP TS 43.022. For UMTS see 3GPP TS 25.304.
`
`Available PLMN/access technology combination: This is an available PLMN in a specific access technology.
`
`Camped on a cell: The MS (ME if there is no SIM) has completed the cell selection/reselection process and has chosen
`a cell from which it plans to receive all available services. Note that the services may be limited, and that the PLMN
`may not be aware of the existence of the MS (ME) within the chosen cell.
`
`Current serving cell: This is the cell on which the MS is camped.
`
`CTS MS: An MS capable of CTS services is a CTS MS.
`
`EHPLMN: Any PLMN declared as equivalent to the HPLMN, the HPLMN included, is called an EHPLMN.
`
`Equivalent HPLMN list: To allow provision for multiple HPLMN codes, PLMN codes equivalent to the HPLMN
`code derived from the IMSI are stored on the SIM. This is known as the EHPLMN list.
`
`GPRS MS: An MS capable of GPRS services is a GPRS MS.
`
`MS operation mode: See 3GPP TS 23.060 [27].
`
`High quality signal: The high quality signal limit is used in the PLMN selection procedure. It is defined in the
`appropriate AS specification: 3GPP TS 43.022 for the GSM radio access technology, 3GPP TS 25.304 for the UMTS
`radio access technology (FDD or TDD mode).
`
`Home PLMN: This is a PLMN where the MCC and MNC of the PLMN identity match the MCC and MNC of the
`IMSI. Matching criteria are defined in Annex A.
`
`In A/Gb mode,...: Indicates this clause applies only to GSM System. For multi system case this is determined by the
`current serving radio access network.
`
`In Iu mode,...: Indicates this clause applies only to UMTS System. For multi system case this is determined by the
`current serving radio access network.
`
`Localised Service Area (LSA): A localised service area consists of a cell or a number of cells. The cells constituting a
`LSA may not necessarily provide contiguous coverage.
`
`Location Registration (LR): An MS which is IMSI attached to non-GPRS services only performs location registration
`by the Location Updating procedure. A GPRS MS which is IMSI attached to GPRS services or to GPRS and non-GPRS
`services performs location registration by the Routing Area Update procedure only when in a network of network
`operation mode I. Both procedures are performed independently by the GPRS MS when it is IMSI attached to GPRS
`and non-GPRS services in a network of network operation mode II or III (see 3GPP TS 23.060).
`
`MS: Mobile Station. The present document makes no distinction between MS and UE.
`
`Network Type: The network type associated with HPLMN or a PLMN on the PLMN selector (see 3GPP TS 31.102).
`The MS uses this information to determine what type of radio carrier to search for when attempting to select a specific
`PLMN. A PLMN may support more than one network type.
`
`Registered PLMN (RPLMN): This is the PLMN on which certain LR outcomes have occurred (see table 1). In a
`shared network the RPLMN is the PLMN defined by the PLMN identity of the CN operator that has accepted the LR.
`
`Registration: This is the process of camping on a cell of the PLMN and doing any necessary LRs.
`
`Registration Area: A registration area is an area in which mobile stations may roam without a need to perform location
`registration. The registration area corresponds to location area (LA) for performing location updating procedure and it
`corresponds to routing area for performing the routing area update procedure.
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`The PLMN to which a cell belongs (PLMN identity) is given in the system information transmitted on the BCCH (MCC
`+ MNC part of LAI). In a shared network a cell belongs to all PLMNs given in the system information transmitted on
`the BCCH.
`
`Selected PLMN: This is the PLMN that has been selected according to clause 3.1, either manually or automatically.
`
`Shared Network: An MS considers a cell to be part of a shared network, when multiple PLMN identities are received
`on the BCCH.
`
`SIM: Subscriber Identity Module (see 3GPP TS 21.111). The present document makes no distinction between SIM and
`USIM.
`
`SoLSA exclusive access: Cells on which normal camping is allowed only for MS with Localised Service Area (LSA)
`subscription.
`
`Suitable Cell: This is a cell on which an MS may camp. It must satisfy criteria which is defined for A/Gb mode in
`3GPP TS 43.022 and for Iu mode in 3GPP TS 25.304.
`
`Visited PLMN: This is a PLMN, different from the home PLMN.
`
`2
`
`General description of idle mode
`
`When an MS is switched on, it attempts to make contact with a public land mobile network (PLMN). The particular
`PLMN to be contacted may be selected either automatically or manually.
`
`The MS looks for a suitable cell of the chosen PLMN and chooses that cell to provide available services, and tunes to its
`control channel. This choosing is known as "camping on the cell". The MS will then register its presence in the
`registration area of the chosen cell if necessary, by means of a location registration (LR), GPRS attach or IMSI attach
`procedure.
`
`If the MS loses coverage of a cell, or find a more suitable cell, it reselects onto the most suitable cell of the selected
`PLMN and camps on that cell. If the new cell is in a different registration area, an LR request is performed.
`
`If the MS loses coverage of a PLMN, either a new PLMN is selected automatically, or an indication of which PLMNs
`are available is given to the user, so that a manual selection can be made.
`
`Registration is not performed by MSs only capable of services that need no registration.
`
`The purpose of camping on a cell in idle mode is fourfold:
`
`a) It enables the MS to receive system information from the PLMN.
`
`b) If the MS wishes to initiate a call, it can do this by initially accessing the network on the control channel of the
`cell on which it is camped (with the exceptions defined in 3GPP TS 43.022 clauses 3.5.3 and 3.5.4 and 3GPP TS
`25.304).
`
`c) If the PLMN receives a call for the MS, it knows (in most cases) the registration area of the cell in which the MS
`is camped. It can then send a "paging" message for the MS on control channels of all the cells in the registration
`area. The MS will then receive the paging message because it is tuned to the control channel of a cell in that
`registration area, and the MS can respond on that control channel.
`
`d) It enables the MS to receive cell broadcast messages.
`
`If the MS is unable to find a suitable cell to camp on, or the SIM is not inserted, or if it receives certain responses to an
`LR request (e.g., "illegal MS"), it attempts to camp on a cell irrespective of the PLMN identity, and enters a "limited
`service" state in which it can only attempt to make emergency calls.
`
`In A/Gb mode, if the CTS MS is in CTS mode only or in automatic mode with CTS preferred, it will start by attempting
`to find a CTS fixed part on which it is enrolled
`
`The idle mode tasks can be subdivided into 4 processes:
`
`- PLMN selection;
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`- Cell selection and reselection;
`
`- Location registration;
`
`- CTS fixed part selection (A/Gb mode only).
`
`In A/Gb mode, to make this initial CTS fixed part selection, the MS shall be enrolled on at least one fixed part.
`
`The relationship between these processes is illustrated in figure 1 in clause 5. The states and state transitions within
`each process are shown in figures 2 to 4 in clause 5.
`
`3
`
`Requirements and technical solutions
`
`The following clauses list the main requirements of idle mode operation and give an outline of the technical solution.
`
`3.1
`
`PLMN selection and roaming
`
`The MS normally operates on its home PLMN (HPLMN). However a visited PLMN (VPLMN) may be selected, e.g., if
`the MS loses coverage. There are two modes for PLMN selection:
`
`i) Automatic mode - This mode utilizes a list of PLMNs in priority order. The highest priority PLMN which is
`available and allowable is selected.
`
`ii) Manual mode - Here the MS indicates to the user which PLMNs are available. Only when the user makes a
`manual selection does the MS try to obtain normal service on the VPLMN.
`
`There are two cases:
`
`-
`
`International Roaming - This is where the MS receives service on a PLMN of a different country than that of the
`HPLMN.
`
`- National Roaming - This is where the MS receives service from a PLMN of the same country as that of the
`HPLMN, either anywhere or on a regional basis. The MS makes a periodic search for the HPLMN while
`national roaming.
`
`To prevent repeated attempts to have roaming service on a not allowed LA, when the MS is informed that an LA is
`forbidden, the LA is added to a list of "forbidden LAs for roaming" which is stored in the MS. This list is deleted when
`the MS is switched off or when the SIM is removed. Such area restrictions are always valid for complete location areas
`independent of possible subdivision into GPRS routing areas. The structure of the routing area identifier (3GPP TS
`23.003) supports area restriction on LA basis.
`
`If a "No Suitable Cells In Location Area" message is received by an MS, that location area is added to the list of
`"forbidden LAs for roaming" which is stored in the MS. The MS shall then search for a suitable cell in the same PLMN
`but belonging to an LA which is not in the "forbidden LAs for roaming" list.
`
`If a "PLMN not allowed" message is received by an MS in response to an LR request from a VPLMN, that VPLMN is
`added to a list of "forbidden PLMNs" in the SIM and thereafter that VPLMN will not be accessed by the MS when in
`automatic mode. A PLMN is removed from the "forbidden PLMNs" list if, after a subsequent manual selection of that
`PLMN, there is a successful LR. This list is retained when the MS is switched off or the SIM is removed. The HPLMN
`shall not be stored on the list of "forbidden PLMNs".
`
`In A/Gb mode, an ME not supporting SoLSA may consider a cell with the escape PLMN code (see 3GPP TS 23.073) to
`be a part of a PLMN belonging to the list of "forbidden PLMNs".
`
`Optionally the ME may store in its memory an extension of the "forbidden PLMNs" list. The contents of the extension
`of the list shall be deleted when the MS is switched off or the SIM is removed.
`
`If a "GPRS services not allowed in this PLMN" message is received by an MS in response to an GPRS attach, GPRS
`detach or routing area update request from a VPLMN, that VPLMN is added to a list of "forbidden PLMNs for GPRS
`service" which is stored in the MS and thereafter that VPLMN will not be accessed by the MS for GPRS service when
`in automatic mode. This list is deleted when the MS is switched off or when the SIM is removed. A PLMN is removed
`from the list of "forbidden PLMNs for GPRS service" if, after a subsequent manual selection of that PLMN, there is a
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`successful GPRS attach. The maximum number of possible entries in this list is implementation dependant, but must be
`at least one entry. The HPLMN shall not be stored on the list of "forbidden PLMNs for GPRS service".
`
`3.2
`
`Regional provision of service
`
`An MS may have a "regionally restricted service" where it can only obtain service on certain LAs. If such an MS
`attempts to camp on a cell of an LA for which it does not have service entitlement, when it does an LR request, it will
`receive an "LA not allowed" message. In this case:
`
`- The MS stores the forbidden LA identity (LAI) in a list of "forbidden LAs for regional provision of service", to
`prevent repeated access attempts on a cell of the forbidden LA. This list is deleted when the MS is switched off
`or the SIM is removed. The MS enters the limited service state.
`
`In A/Gb mode, a cell may be reserved for SoLSA exclusive access (see 3GPP TS 24.008 and 3GPP TS 44.060). An MS
`is only allowed to camp normally on such a cell if it has a Localised Service Area subscription to the cell. Other MS
`may enter the limited service state.
`
`NOTE:
`
`In A/Gb mode, in a SoLSA exclusive cell the MCC+MNC code is replaced by an unique escape PLMN
`code (see 3GPP TS 23.073), not assigned to any PLMN, in SI3 and SI4. An MS not supporting SoLSA
`may request for location update to an exclusive access cell. In this case the location attempt is rejected
`with the cause "PLMN not allowed" and the escape PLMN code is added to the list of the "forbidden
`PLMNs".
`
`3.3
`
`Borders between registration areas
`
`If the MS is moving in a border area between registration areas, it might repeatedly change between cells of different
`registration areas. Each change of registration area would require an LR, which would cause a heavy signalling load and
`increase the risk of a paging message being lost. The access stratum shall provide a mechanism to limit this effect.
`
`3.4
`
`Access control
`
`3.4.1
`
`Access control
`
`Due to problems in certain areas, Network Operators may decide to restrict access from some MSs (e.g., in case of
`congestion), and for this reason an access control mechanism shall be provided.
`
`3.4.2
`
`Forbidden LA for regional provision of service
`
`When the MS is camped on a cell, the LA of which belongs to the list of "forbidden LAs for regional provision of
`service", the MS is not allowed to initiate establishment of a CM connection except for an emergency call; it may
`respond to paging. Also, the MS is not allowed to request GPRS services when camped on a cell of a LA of which
`belongs to the list of "forbidden LAs for regional provision of service".
`
`3.5
`
`No suitable cell (limited service state)
`
`There are a number of situations in which the MS is unable to obtain normal service from a PLMN. These include:
`
`a) Failure to find a suitable cell of the selected PLMN;
`
`b) No SIM in the MS;
`
`c) A "PLMN not allowed" response to an LR;
`
`d) An "illegal MS", "illegal ME" or "IMSI unknown in HLR" response to an LR; (Any SIM in the ME is then
`considered "invalid".)
`
`e) A "GPRS not allowed" response to an LR of a GPRS MS attached to GPRS services only. (The cell selection
`state of GPRS MSs attached to GPRS and non-GPRS depends on the outcome of the location updating.)
`
`3GPP
`
`

`

`
`
` Release 7
`
`11
`
`3GPP TS 23.122 V7.0.0 (2005-01)
`
`(In automatic PLMN selection mode, events (a), (c) and (e) would normally cause a new PLMN selection, but even
`here, the situation may arise when no PLMNs are available and allowable for use).
`
`Under any of these conditions, the MS attempts to camp on an acceptable cell, irrespective of its PLMN identity, so that
`emergency calls can be made if necessary. When in the limited service state with a valid SIM, the MS shall search for
`available and allowable PLMNs in the manner described in clause 4.4.3.1 and when indicated in the SIM also as
`described in clause 4.4.3.4. No LR requests are made until a valid SIM is present and either a suitable cell is found or a
`manual network reselection is performed. In the limited service state the presence of the MS need not be known to the
`PLMN on whose cell it has camped.
`
`There are also other conditions under which only emergency calls may be made. These are shown in table 2 in clause 5.
`
`3.6
`
`CTS fixed part selection (A/Gb mode only)
`
`In CTS mode only or in automatic mode with CTS preferred, the CTS MS normally operates on a CTS fixed part on
`which the mobile station is already enrolled. If the CTS MS loses CTS coverage in these modes, it shall attempt
`periodically to select again a CTS fixed part.
`
`To select a CTS fixed part, the CTS MS shall listen to the CTSBCH frequencies of all the fixed parts on which the MS
`is currently enrolled.
`
`If the CTS MS is moving in a border area between one area with CTS coverage and one without it, it might repeatedly
`require CTS attachments and LU on the PLMN. To prevent this, the criteria C1_CTS and C2_CTS (defined in 3GPP TS
`45.008 clause 11.1) are used. To attach to a CTS FP, the C1_CTS criterion shall be greater than zero. When the
`C2_CTS criterion falls below zero, the CTS MS shall consider itself to be no more under CTS coverage.
`
`4
`
`Overall process structure
`
`4.1
`
`Process goal
`
`The aim of the idle mode processes is to ensure that the registered PLMN is the selected PLMN.
`
`4.2
`
`States description
`
`Each of the processes of PLMN selection, cell selection and location registration can be described by a set of states. The
`overall state of the mobile is thus a composite of the states of the three pro