ETSI TS 143 022 V13.1.0 (2016-08)

ETSI TS 1143 022 V13.1.0 (201616-08)

TECHNICAL SPECIFICATIONION
Digital cellular telecommmmunications system (Phase e 2+) (GSM);
Functions relrelated to Mobile Station (MSS))
in idle modede and group receive mode
(3GPP TS 43.0.022 version 13.1.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS
3GPP TS 43.022 version 13.1.0 Release 13 1 ETSI TS 143 022 V13.1.0 (2016-08)

Reference
RTS/TSGG-0143022vd10
Keywords
GSM
ETSI
650 Route des Lucioles
F-06921 Sophia Antipolis Cedex - FRANCE

Tel.: +33 4 92 94 42 00  Fax: +33 4 93 65 47 16

Siret N° 348 623 562 00017 - NAF 742 C
Association à but non lucratif enregistrée à la
Sous-Préfecture de Grasse (06) N° 7803/88

Important notice
The present document can be downloaded from:
http://www.etsi.org/standards-search
The present document may be made available in electronic versions and/or in print. The content of any electronic and/or
print versions of the present document shall not be modified without the prior written authorization of ETSI. In case of any
existing or perceived difference in contents between such versions and/or in print, the only prevailing document is the
print of the Portable Document Format (PDF) version kept on a specific network drive within ETSI Secretariat.
Users of the present document should be aware that the document may be subject to revision or change of status.
Information on the current status of this and other ETSI documents is available at
https://portal.etsi.org/TB/ETSIDeliverableStatus.aspx
If you find errors in the present document, please send your comment to one of the following services:
https://portal.etsi.org/People/CommiteeSupportStaff.aspx
Copyright Notification
No part may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying
and microfilm except as authorized by written permission of ETSI.
The content of the PDF version shall not be modified without the written authorization of ETSI.
The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2016.
All rights reserved.
TM TM TM
DECT , PLUGTESTS , UMTS and the ETSI logo are Trade Marks of ETSI registered for the benefit of its Members.
TM
3GPP and LTE™ are Trade Marks of ETSI registered for the benefit of its Members and
of the 3GPP Organizational Partners.
GSM® and the GSM logo are Trade Marks registered and owned by the GSM Association.
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 2 ETSI TS 143 022 V13.1.0 (2016-08)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 3 ETSI TS 143 022 V13.1.0 (2016-08)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
1.1 References . 6
1.2 Definitions and abbreviations . 7
2 General description of idle mode . 9
3 Requirements and technical solutions . 9
3.1 PLMN selection and roaming . 9
3.2 Camping on a cell . 9
3.2.1 Normal camping . 9
3.2.2 "Camp on any cell" . 10
3.3 Regional provision of service . 10
3.4 Borders between registration areas . 10
3.5 Barred cells and access control . 10
3.5.1 Barred cells . 10
3.5.2 Prioritizing cells . 10
3.5.2.1 For cell selection . 11
3.5.2.2 For cell reselection . 11
3.5.3 Access control . 11
3.5.4 Forbidden LA for regional provision of service . 11
3.5.5 Barred cell due to failed network authentication check . 11
3.6 Radio constraints . 11
3.7 No suitable cell (limited service state) . 12
3.8 CTS fixed part selection . 12
4 Overall process structure . 12
4.1 Process goal . 12
4.2 States description . 13
4.3 List of states . 13
4.3.1 List of states for the PLMN selection process . 13
4.3.2 List of States for the cell selection process (figure 3) . 13
4.3.3 List of states for location updating . 14
4.3.4 List of states for location registration . 14
4.4 PLMN selection process . 14
4.4.1 Introduction. 14
4.4.2 Registration on a PLMN . 14
4.4.3 PLMN selection . 14
4.4.4 Abnormal cases . 14
4.4.5 Roaming not allowed in this LA . 14
4.5 Cell selection process . 14
4.6 Location registration process . 17
4.7 Service indication . 17
4.8 BCCH allocation broadcasting and storage . 17
4.9 Pageability of the mobile subscriber . 18
4.10 MM Restart procedure . 18
5 Group receive mode . 18
5.1 General description. 18
5.2 Requirements and technical solutions . 18
5.2.1 Network provisions . 18
5.2.2 Group receive mode cell monitoring . 19
5.2.3 Group receive mode cell change . 20
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 4 ETSI TS 143 022 V13.1.0 (2016-08)
5.2.4 Uplink access in group calls . 20
5a Broadcast/multicast receive mode . 20
5a.1 General description. 20
5a.2 Requirements and technical solutions . 21
5a.2.1 Network provisions . 21
5a.2.2 Broadcast/multicast receive mode cell monitoring . 21
5a.2.3 Broadcast/multicast receive mode cell change . 21
6 Tables and figures . 22
Annex A (informative): Change history . 23
History . 25

ETSI
3GPP TS 43.022 version 13.1.0 Release 13 5 ETSI TS 143 022 V13.1.0 (2016-08)
Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
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:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 6 ETSI TS 143 022 V13.1.0 (2016-08)
1 Scope
The present document gives an overview of the tasks undertaken by a GSM Mobile Station (MS) when in idle mode,
that is, switched on but not having a dedicated channel allocated (e.g. not making or receiving a call), when in group
receive mode, that is, receiving a voice group call or voice broadcast call but not having a dedicated connection or when
in broadcast/multicast receive mode, that is, receiving an MBMS session but 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 idle mode functions are also performed by a CTS MS as long
as the CTS MS is in manual mode GSM only or in automatic mode under PLMN coverage.
NOTE: The term GSM MS is used for any type of MS supporting one, or combinations, of the frequency bands
specified in 3GPP TS 45.005.
The present document outlines how the requirements of the 3GPP TS 22 series Technical Specifications (especially
3GPP TS 22.011) on idle mode operation shall be implemented. Further details are given in 3GPP TS 44.018 and 3GPP
TS 45.008.
Clause 2 of the present document 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. Clause 5 describes the cell change procedures for a MS in group receive
mode. Clause 5a describes the cell change procedures for a MS in broadcast/multicast receive mode.
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.
[1] 3GPP TS 21.905: "Vocabulary for 3GPP Specifications".
[2] (void)
[3] (void)
[4] (void)
[5] (void)
[6] (void)
[7] (void)
[8] (void)
[9] 3GPP TS 22.011: " Service accessibility".
[10] (void)
[11] (void)
[12] (void)
[13] (void)
[14] (void)
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 7 ETSI TS 143 022 V13.1.0 (2016-08)
[15] (void)
[16] (void)
[17] (void)
[18] (void)
[19] (void)
[20] (void)
[21] (void)
[22] (void)
[23] 3GPP TS 44.018: "Mobile radio interface layer 3 specification; Radio Resource Control (RRC)
protocol".
[24] (void)
[25] 3GPP TS 45.008: "Radio subsystem link control".
[26] 3GPP TS 22.060: "General Packet Radio Service (GPRS); Service description; Stage 1".
[27] 3GPP TS 23.060: "General Packet Radio Service (GPRS); Service description; Stage 2".
[28] 3GPP TS 43.064: "General Packet Radio Service (GPRS); Overall description of the GPRS Radio
Interface; Stage 2".
[29] (void)
[30] (void)
[31] 3GPP TS 23.122: " Non-Access-Stratum functions related to Mobile Station (MS) in idle mode".
[32] 3GPP TS 24.008: " Mobile radio interface layer 3 specification; Core Network Protocols - Stage
3".
[33] 3GPP TS 31.102: "Characteristics of the USIM application".
[34] 3GPP TS 43.068: "Voice Group Call Service (VGCS); Stage 2".
[35] 3GPP TS 43.069: "Voice Broadcast service (VBS); Stage 2".
[36] 3GPP TS 45.005: "Radio transmission and reception".
[37] 3GPP TS 51.011: "Specification of the Subscriber Identity Module - Mobile Equipment (SIM-ME)
interface" (Release 4).
[38] 3GPP TS 43.246: "Multimedia Broadcast Multicast Service (MBMS) in the GERAN; Stage 2".
[39] 3GPP TS 22.268: "Public Warning System (PWS) requirements; Stage 1".
[40] 3GPP TS 23.682: "Architecture enhancements to facilitate communications with packet data
networks and applications".
1.2 Definitions and abbreviations
For the purposes of the present document, the terms and definitions given in 3GPP TS 21.905 [1] and the following
apply.
Selected PLMN This is the PLMN that has been selected according to subclause 3.1, either
manually or automatically.
Available PLMN This is a PLMN where the MS has found a cell that satisfies conditions (ii) and
(iv) of subclause 3.2.1.
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 8 ETSI TS 143 022 V13.1.0 (2016-08)
Home PLMN (HPLMN) See 3GPP TS 23.122 [31].
Registered PLMN (RPLMN) This is the PLMN on which certain LR outcomes have occurred (see 3GPP
TS 23.122 [31]).
Equivalent PLMN A PLMN contained in the stored list of equivalent PLMNs. These PLMNs are
considered equivalent to the selected PLMN regarding PLMN selection, cell
selection, cell re-selection and handover (see 3GPP TS 23.122 [31]).
Registration This is the process of camping on a cell of the PLMN and doing any necessary
LRs.
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.
Suitable Cell This is a cell on which an MS may camp. It must satisfy criteria defined in
subclause 3.2.1. For an MS in group receive mode, the suitable cell is determined
by the criteria defined in subclause 5.2.3.
Acceptable Cell This is a cell that the MS may camp on to make emergency calls and to receive
warning notifications. It must satisfy criteria defined in sub clause 3.2.2.
EC operation See 3GPP TS 43.064 [28].
Group call A communication in which several MSs can receive, but at most one may be
allowed to transmit on a radio channel. Examples of group calls are those
established for the voice group call service (VGCS, see 3GPP TS 43.068 [34]).
Broadcast call A communication in which several MSs can receive, but only the originator of the
call is allowed to transmit on the radio channel. Examples of the broadcast call are
those established for the voice broadcast service (VBS, see 3GPP TS 43.069 [35]).
Group receive mode State of the MS when it is engaged in a voice group or voice broadcast call as a
listener.
GPRS MS An MS capable of GPRS services is a GPRS MS.
CTS MS An MS capable of CTS services is a CTS MS.
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 [27]).
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.
Power Efficient Operation See 3GPP TS43.064 [28].
Power Saving Mode (PSM): Mode allowing the MS to reduce its power consumption, as defined in TS 24.008
[32], TS 23.060 [27], TS 23.682 [40].
SoLSA exclusive access Cells on which normal camping is allowed only for MS with Localised Service
Area (LSA) subscription.
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.
The PLMN to which a cell belongs (PLMN identity) is given in the system information transmitted on the BCCH (MCC
+ MNC part of LAI).
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 9 ETSI TS 143 022 V13.1.0 (2016-08)
2 General description of idle mode
See 3GPP TS 23.122.
When NAS indicates that PSM starts (as defined in 3GPP TS 23.682 [40]) the MS shall suspend all AS functions and
consequently all idle mode tasks until when NAS indicates that PSM ends the MS shall resume all AS functions and all
idle mode tasks.
3 Requirements and technical solutions
The following subclauses list the main requirements of idle mode operation and give an outline of the technical
solution.
3.1 PLMN selection and roaming
See 3GPP TS 23.122.
3.2 Camping on a cell
3.2.1 Normal camping
For normal service, the MS has to camp on a suitable cell, tune to that cell's control channel(s), and possibly register
within the PLMN so that the MS can:
a) Receive system information from the PLMN , e.g., the cell options ;
b) Receive paging messages from the PLMN, e.g., when there is an incoming call for the MS;
c) Initiate call setup for outgoing calls or other actions from the MS (where possible, see subclauses 3.5.3 and
3.5.4).
The choice of such a suitable cell for the purpose of receiving normal service is referred to as "normal camping". There
are various requirements that a cell must satisfy before an MS can perform normal camping on it:
i) It should be a cell of the selected PLMN or, if the selected PLMN is equal to the last registered PLMN, an
equivalent PLMN;
ii) It should not be "barred" (see subclause 3.5.1);
iii) It should not be in an LA which is in the list of "forbidden LAs for roaming";
iv) The radio path loss between MS and BTS must be below a threshold set by the PLMN operator. This is
estimated as shown in subclause 3.6;
v) It should not be a SoLSA exclusive cell to which MS does not subscribe. This requirement is only valid for MSs
supporting SoLSA.
Initially, the MS looks for a cell which satisfies these 5 constraints ("suitable cell") by checking cells in descending
order of received signal strength. If a suitable cell is found, the MS camps on it and performs any registration necessary.
Cells can have two levels of priority, suitable cells which are of low priority are only camped on if there are no other
suitable cells of normal priority. (This is called "cell selection").
When camped on a cell the MS regularly looks to see if there is a better cell in terms of a cell re-selection criterion, and
if there is, the better cell is selected. Also if one of the other criteria changes, (e.g., the current serving cell becomes
barred), or there is a downlink signalling failure (see subclause 3.6), a new cell is selected. (This is called "cell
reselection"). A MS that has enabled PEO or EC operation has relaxed requirements for how often it verifies the
suitability of its serving cell and the suitability of neighbour cells for re-selection (see 3GPP TS 45.008 [25] and 3GPP
TS 44.018 [23]).
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 10 ETSI TS 143 022 V13.1.0 (2016-08)
In order to speed up these processes, a list of the RF channels containing BCCH or CPBCCH carriers of the same
PLMN is broadcast in the system information messages, see subclause 4.8. Also, the MS does not need to search all
possible RF channels to find a suitable cell. If, after searching the number of RF channels, given for each frequency
band below, with the strongest received signal level, a BCCH or CPBCCH carrier has been found but no suitable cell of
the selected PLMN has been found, the MS can stop the attempt to find a suitable cell of the selected PLMN.
The number of channels to be searched are 15 for T-GSM 380, 15 for T-GSM 410, 15 for GSM 450, 15 for GSM 480,
25 for GSM 710, 25 for GSM 750, 25 for T-GSM 810, 30 for GSM 850 Band, 30 for GSM 900, 15 for T-GSM 900 and
40 for DCS 1800 and PCS 1900.
3.2.2 "Camp on any cell"
If the MS cannot find a suitable cell, it attempts to camp on any acceptable cell and enter a "limited service state", as
defined in subclause 3.7. An MS attempting to camp on any acceptable cell shall not scan for CPBCCH.
There are various requirements that a cell must satisfy before being considered an acceptable cell to be camped on in
"limited service state":
i) It should not be "barred" (see subclause 3.5.1);
ii) The radio path loss between MS and BTS must be below a threshold set by the PLMN operator. This is
estimated as shown in subclause 3.6.
3.3 Regional provision of service
See 3GPP TS 23.122.
3.4 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. To prevent this, a "CELL_RESELECT_HYSTERESIS" (CRH)
parameter is used. A cell in a different registration area is only selected if it is "better", in terms of the path loss criterion
(see subclause 3.6), than all the cells in the current registration area by at least the value of CRH. The CRH parameter is
broadcast as system information. As the value of CRH broadcast may be different on different cells, the CRH parameter
to be used is that broadcast on the current serving cell. There is also a lower limit on the time interval between
reselection of cells on different registration areas. Instead of CRH a GPRS MS uses a
"GPRS_CELL_RESELECT_HYSTERESIS" if provided.
3.5 Barred cells and access control
3.5.1 Barred cells
The PLMN operator may decide not to allow MSs to camp on certain cells. (These cells may, for example, only be used
for hand over traffic, i.e. calls which need to be handed over to other cells). Barred cell information is broadcast as
system information to instruct MSs not to camp on these cells. The barred cell status may in fact change dynamically;
hence the MS needs to regularly check the system information for this parameter.
The barred status of a cell depends on the parameters CELL_BAR_ACCESS and CELL_BAR_QUALIFY, further
described in 3GPP TS 45.008 [25]. For a MS that has enabled EC operation, the barred status of a cell is given by the
Implicit Reject Status broadcast in EC-SCH, see 3GPP TS 44.018 [23].
If a cell is barred this applies both for cell selection and reselection.
3.5.2 Prioritizing cells
In general, cell prioritization is a means of encouraging MSs to select some suitable cells in preference to others. Since
the priority comparison is only between suitable cells, prioritization does not affect coverage. Operators may prefer a
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 11 ETSI TS 143 022 V13.1.0 (2016-08)
certain type of cell not to be selected unless it is the only suitable type. For example, umbrella cells due to their large
frequency reuse distance, or microcells because the MS could be travelling too fast for them.
3.5.2.1 For cell selection
During cell selection (see subclause 3.2.1), a cell with low priority indication will only be selected if a suitable cell of
normal priority cannot be found.
3.5.2.2 For cell reselection
Cell prioritization can also be achieved during cell reselection by the use of the reselection parameters optionally
broadcast. Cells are reselected on the basis of a parameter called C2 and the C2 value for each cell is given a positive or
negative offset to encourage or discourage MSs to reselect that cell. A full range of positive and negative offsets is
provided to allow the incorporation of this feature into already operational networks. Instead of C2 a GPRS MS uses the
GPRS cell reselection parameter if provided.
An MS supporting SoLSA with SoLSA subscription shall use the SoLSA cell re-selection parameters.
3.5.3 Access control
Due to problems in certain areas, Network Operators may decide to restrict access from some MSs (e.g., in case of
congestion on the AGCH), and for this reason the access control mechanism is provided.
At subscription one or more access control classes are allocated to the subscriber and stored in the SIM. The
information providing all authorized classes is broadcast as system information (together with a bit indicating whether
emergency calls may be made). This information is modified dynamically and therefore the MS has to check the system
information before each attempt to access.
The MS ignores the Access Control information when selecting a cell to camp on, i.e. it shall not reject a cell for
camping on because access on that cell is not allowed.
3.5.4 Forbidden LA for regional provision of service
If the MS has received the cause "LA not allowed", it shall ignore this fact when selecting a cell to camp on, i.e. it shall
not reject a cell for camping on because that cell is part of a LA where this cause has been received.
3.5.5 Barred cell due to failed network authentication check
If upper layers have determined that the network has failed an authentication check (3GPP TS 24.008), the MS shall
treat this cell as if the barred status broadcasted in the system information is set and reselect another cell. The MS shall
treat the cell as barred for a period equal to the MM timer T3212 minus 60 seconds if the MM authentication procedure
was performed or equal to the GMM timer T3302 minus 60 seconds if the GMM authentication was performed (see
3GPP TS 24.008). If the timer T3212 or T3302 are disabled by the network a default value of 12 hours shall be used.
3.6 Radio constraints
The MS uses a "path loss criterion" parameter C1 to determine whether a cell is suitable to camp on. C1 depends on 4
parameters:
i) The received signal level (suitably averaged);
ii) The parameter RXLEV_ACCESS_MIN, which is broadcast as system information, and is related to the
minimum signal that the operator wants the network to receive when being initially accessed by an MS;
iii) The parameter MS_TXPWR_MAX_CCH, which is also broadcast as system information, and is the maximum
power that an MS may use when initially accessing the network;
iv) The maximum power of the MS.

ETSI
3GPP TS 43.022 version 13.1.0 Release 13 12 ETSI TS 143 022 V13.1.0 (2016-08)
The formula for determining C1 is given in 3GPP TS 45.008 [25].
Use of the parameter C1 enables the MS to determine whether communication is possible with the network in the
absence of interference. However because of the possibility of interference degrading the communications, an
additional safeguard is used. This is to monitor the success rate of the MS in decoding signalling blocks of the paging
subchannel except when EC operation is enabled in which case the MS monitors the time required to decode the EC-
SCH. If there is a downlink signalling failure, i.e. the success rate drops too low (or, in case EC operation is enabled,
the maximum time to decode EC-SCH is exceeded), this indicates probable interference on the downlink, and the MS
attempts to find another suitable cell. Downlink signalling failure monitoring is specified in 3GPP TS 45.008 [25].
In order to optimize cell reselection, additional cell reselection parameters can be broadcast as system information of
each cell. The cell reselection process employs a parameter C2 which depends on these parameters.
The parameters used to calculate C2 are as follows:
i) CELL_RESELECT_OFFSET (see subclause 3.5.2.2);
ii) PENALTY_TIME;
When the MS places the cell on the list of the strongest carriers as specified in 3GPP TS 45.008 [25], it starts a
timer which expires after the PENALTY_TIME. This timer will be reset when the cell is taken off the list. For
the duration of this timer, C2 is given a negative offset. This will tend to prevent fast moving MSs from selecting
the cell.
iii) TEMPORARY_OFFSET;
This is the amount of the negative offset described in (ii) above. An infinite value can be applied, but a number
of finite values are also possible.
The permitted values of these parameters and the way in which they are combined to calculate C2 are defined in 3GPP
TS 45.008 [25].
Instead of the parameter C2, a GPRS MS applies the corresponding GPRS parameter if provided.
A MS that supports EC-GSM-IoT applies EC-specific C1 and C2 parameters.
An MS supporting SoLSA with SoLSA subscription shall use the SoLSA cell re-selection parameters.
3.7 No suitable cell (limited service state)
If the MS is unable to obtain normal service from a PLMN (see 3GPP TS 23.122), the MS attempts to camp on an
acceptable cell, irrespective of its PLMN identity, so that emergency calls can be made or warning notifications can be
received if necessary. To minimize the time taken to find new available PLMNs while maintaining battery life,
discontinuous search schemes may be used, see 3GPP TS 22.011. Cell reselection takes place as normal, except that a
zero dB value of CRH will be used.
3.8 CTS fixed part selection
See 3GPP TS 23.122
4 Overall process structure
4.1 Process goal
The aim of the idle mode processes is to achieve the following conditions ("normal service state"):
a) The selected PLMN is one of the equivalent PLMNs;
b) The MS is camped on a suitable cell of the registration area on which the last successful LR was performed, and
that cell has the highest value of C2 for any unbarred cell in that registration area;
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 13 ETSI TS 143 022 V13.1.0 (2016-08)
c) The value of C2 for the MS is not lower than the value of C2 for any suitable cell in another registration area of
an equivalent PLMN by more than the hysteresis value CRH.
Instead of the parameter C2, a GPRS MS applies the corresponding GPRS parameter if provided.
An MS supporting SoLSA with SoLSA subscription shall use the SoLSA cell re-selection parameters.
Registration is not performed by MSs only capable of services which need no registration.
There may be temporary conditions under which not all these are fully satisfied, e.g., during cell selection on a PLMN,
while in the process of reselecting another cell or, in case EC operation is enabled, when none of the criteria triggering
neighbour cell measurements are fulfilled (see 3GPP TS 45.008 [25]). However, if the above cannot be satisfied for a
certain period of time, the MS will normally enter a "limited service state" in which it will try to camp on an acceptable
cell. In this state, only emergency calls and warning notifications are possible.
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 processes. In some cases, an event which causes
a change of state in one process may trigger a change of state in another process, e.g., camping on a cell in a new
registration area triggers an LR request. The relationship between the processes is illustrated in figure 1 in 3GPP TS
23.122.
In the event of any conflict between the diagrams and the text in this ETS, the text takes precedence.
4.3 List of states
4.3.1 List of states for the PLMN selection process
See 3GPP TS 23.122.
4.3.2 List of States for the cell selection process (figure 3)
C1 Normal Cell Selection - This is the process of initial cell selection, searching all RF channels.
C2 Stored List Cell Selection - This is the process of initial cell selection where BCCH carrier
information (e.g. a BA list) for the selected PLMN is stored in the MS.
C3 Camped Normally - This is where the MS is camped on a cell of the registered PLMN and may be
able to make and receive calls. (Whether or not the MS can make and receive calls depends on the
state within the location registration process). The MS monitors received level and the system
information and checks whether cell reselection is needed.
C4 Normal Cell Reselection - This is where the MS has determined that cell reselection is needed and
an attempt is being made to reselect a new cell.
C5 Choose Cell - This is where the MS has returned to idle mode from "connected mode" and is
choosing a suitable cell to camp on.
C6 Any Cell Selection - This is where the MS is unable to camp normally on any cell of the selected
PLMN, or cannot obtain service because of certain responses to a location registration (LR)
attempt. It is searching for a cell of any PLMN to camp on (so that emergency calls can be made
and warning notifications can be received).
C7 Camped on any Cell - This is where the MS has camped on a cell irrespective of its PLMN
identity, so that emergency calls can be made and warning notifications can be received.
C8 Any Cell Reselection - This is where the MS is attempting to reselect a cell, irrespective of PLMN
identity.
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 14 ETSI TS 143 022 V13.1.0 (2016-08)
C9 Choose Any Cell - This is where the MS is returning to idle mode, after having entered "connected
mode" from the "camped on any cell" state to make an emergency call. It is attempting to find an
acceptable cell to camp on.
For detailed description of the behaviour in the above states see 3GPP TS 45.008.
4.3.3 List of states for location updating
See 3GPP TS 23.122.
4.3.4 List of states for location registration
See 3GPP TS 23.122.
4.4 PLMN selection process
4.4.1 Introduction
See 3GPP TS 23.122.
4.4.2 Registration on a PLMN
An MS successfully registers on a PLMN if:
a) The MS has found a suitable cell of the PLMN to camp on; and
b) An LR request from the MS has been accepted in the registration area of the cell on which the MS is camped
(see 3GPP TS 23.122).
It should be noted that if registration is unsuccessful because no suitable cell could be found, the MS will have had to
search at least the number, given in subclause 3.2.1, of the strongest RF channels (see subclause 3.2) and therefore all
the available PLMNs will potentially have been detected. If registration is unsuccessful because of an LR failure or an
LR rejection, the MS need not necessarily have already searched the number, given in subclause 3.2.1, of the strongest
RF channels, and would need to do so before being in a position to display to the user all available PLMNs (see 3GPP
TS 23.122).
4.4.3 PLMN selection
See 3GPP TS 23.122.
A PLMN shall be understood to be received with high quality signal if the signal level is above -85 dBm.
4.4.4 Abnormal cases
See 3GPP TS 23.122.
4.4.5 Roaming not allowed in this LA
See 3GPP TS 23.122.
4.5 Cell selection process
Whenever a PLMN is selected, the MS attempts to find a suitable cell of that PLMN to camp on. Two methods of
searching for a suitable cell are possible:
a) Normal cell selection ("Normal cell selection" state) - Here the MS has no prior knowledge of which RF
channels are BCCH or CPBCCH carriers. It searches at least the number, given in subclause 3.2.1, of the
ETSI
3GPP TS 43.022 version 13.1.0 Release 13 15 ETSI TS 143 022 V13.1.0 (2016-08)
strongest RF channels in descending order of received signal level to see which are BCCH or CPBCCH carriers.
(If no BCCH or CPBCCH carriers have yet been found, searching will continue until at least one BCCH or
CPBCCH carrier is found.). The first BCCH or CPBCCH carrier found which is from a suitable cell and on
which there is a normal priority indication is taken and that cell is camped on. If at least the number, given in
subclause 3.2.1, of the strongest RF channels have been tried and the only suitable cells found have low priority
indication the MS shall camp on the strongest of these cells.
b) Stored list cell selection (optional) ("Stored list cell selection" state)- Here the MS has a list of the BCCH and
CPBCCH carriers used by the PLMN. (This list may be derived by the MS from information gathered during
previous selections of the PLMN). The BCCH and CPBCCH carriers in the list are searched in descending order
of received signal level, and the first BCCH or CPBCCH carrier found which is from a suitable cell and on
which there is a normal priority indication is taken, and that cell is camped on. If an MS decodes system
information from a cell of the selected PLMN but is unable to camp on that cell, the BA of that cell shall be
examined and any BCCH and CPBCCH carriers in the BA which are not in the list of BCCH or
CPBCCHcarriers to be searched shall be added to the list. If all these BCCH and CPBCCH carriers have been
tried and the only suitable cells found have low priority indication, the MS shall camp on the strongest of these
cells. When required to search for CPBCCH, the stored list cell selection is mandatory for CPBCC
...