ETSI TS 123 094 V12.0.0 (2014-10)

ETSI TS 123 094 V12.0.0 (2014-10)
TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+);
Universal Mobile Telecommunications System (UMTS);
Follow-Me (FM);
Stage 2
(3GPP TS 23.094 version 12.0.0 Release 12)
GLOBAL SYSTEM FOR
MOBILE COMMUNICATIONS
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3GPP TS 23.094 version 12.0.0 Release 12 1 ETSI TS 123 094 V12.0.0 (2014-10)
Reference
RTS/TSGC-0423094vc00
Keywords
GSM,UMTS
ETSI
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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

In the present document "shall", "shall not", "should", "should not", "may", "may not", "need", "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

"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.

Intellectual Property Rights ................................................................................................................................ 2

Foreword ............................................................................................................................................................. 2

Modal verbs terminology .................................................................................................................................... 2

Foreword ............................................................................................................................................................. 4

1 Scope ........................................................................................................................................................ 5

2 References ................................................................................................................................................ 5

3 Definitions and abbreviations ................................................................................................................... 5

3.1 Definitions .......................................................................................................................................................... 5

3.2 Abbreviations ..................................................................................................................................................... 6

4 Handling of Follow Me ............................................................................................................................ 6

4.1 General ............................................................................................................................................................... 6

4.1.1 Provision ....................................................................................................................................................... 7

4.1.2 Registration ................................................................................................................................................... 7

4.1.3 Erasure .......................................................................................................................................................... 7

4.1.4 Interrogation ................................................................................................................................................. 7

4.2 Information Flows .............................................................................................................................................. 7

4.2.1 Information Flow for the handling of FM by the initiating subscriber ......................................................... 7

4.2.2 Information Flow for the handling of FM by the remote party ................................................................... 10

4.3 Handling of FM control in HLRa and FFNb .................................................................................................... 10

4.3.1 Handling of FM control in HLRa ............................................................................................................... 10

4.3.2 Handling of FM control in FFNb ................................................................................................................ 13

4.4 USSD interworking and Cross-phase compatibility ......................................................................................... 22

5 Information stored in the network entities.............................................................................................. 23

5.1 Information stored in HLRa and FFNb ............................................................................................................ 23

5.2 State transition model ....................................................................................................................................... 23

5.3 Information stored in the VLR ......................................................................................................................... 24

5.4 Transfer of information from HLR to VLR ...................................................................................................... 24

Annex A (informative): Checking matrix for FM-CFU interaction in FFNb ................................... 25

Annex B (normative): FM control Messages and their contents ..................................................... 27

B.1 General principles .................................................................................................................................. 27

B.2 Information Elements used in the messages ........................................................................................... 27

B.3 Messages Contents of the FM Request .................................................................................................. 27

B.4 Messages Contents of the HLR-FM-Request ......................................................................................... 28

B.5 Contents and Format of the USSD String of the USSD-Notify ............................................................. 30

B.6 Inter-process Message Init-Notify .......................................................................................................... 31

Annex C (informative): Change history ............................................................................................... 32

History .............................................................................................................................................................. 33

This Technical Specification (TS) 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

y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,

z the third digit is incremented when editorial only changes have been incorporated in the document.

The present document specifies the stage 2 description for the Follow Me feature.

The Follow Me feature enables a mobile subscriber A to manipulate the Follow Me data of a remote party B in such a

way that subsequent calls directed to remote party B will be forwarded to subscriber A.

The following documents contain provisions which, through reference in this text, constitute provisions of the present

• References are either specific (identified by date of publication, edition number, version number, etc.) or

• 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

[6] 3GPP TS 23.011: "Technical realisation of Supplementary Services - General Aspects".

[7] 3GPP TS 23.015: "Technical realisation of Operator Determined Barring (ODB)".

initiating subscriber: mobile subscriber who modifies the Follow Me data of the remote party.

initiating number: number (the MSISDN of the initiating subscriber) to which incoming calls, originally destined for

the remote party, shall be forwarded. It is subsequently also referred to as MSISDN .

remote party: is characterised by the remote number which is defined in the numbering plan of a PLMN operator. The

Follow Me feature enables the initiating subscriber to modify the Follow Me data of the remote party. In particular

cases the remote party is a GSM subscriber of the PLMN and the remote number denotes her basic MSISDN.

Previously registered subscriber: Is the initiating service subscriber who has registered Follow Me with respect to a

remote party. Her Registration can be erased by herself or by an FM service supervisor via forced erasure procedure.

FM service supervisor: is an initiating subscriber who is allowed to modify the Follow Me data of a remote party who

has been registered to a previously registered subscriber for the Follow Me application. The FM service supervisor shall

remote number: is a number in E.164 format which identifies a remote party. In general this number is not assigned to

a subscriber and can be regarded as a "dummy MSISDN". In particular cases the remote party is a GSM subscriber of

the PLMN and the remote number denotes her basic MSISDN. The remote number is entered by the initiating

subscriber for registration, interrogation, forced erasure and erasure of the Follow Me feature with respect to the remote

Follow Me function node: is a network node in the PLMN operator of the remote party. The FM data of the remote

Follow Me enables an initiating mobile subscriber A to have control over the Follow Me data of a remote party B. The

remote party B is characterised by the remote number which is defined in the numbering plan of a PLMN operator.

Initiating Subscriber A shall be able to manipulate the Follow Me data of remote party B such that subsequent calls

destined for remote party B are forwarded to initiating subscriber A. In the case of Forced Erasure by an FM service

supervisor, the initiating subscriber is allowed to erase the Follow Me data of a remote party who has been registered to

Follow Me is a PLMN specific feature and the control operations of FM are based on USSD. All messages between the

The present document deals with the control operations of FM in HLRa and FFN. If the FFN is an HLR, the control of

The functionality of forwarding calls for remote party B to initiating subscriber A (after successful registration of FM)

is out of the scope of the present document. This functionality is the same as the functionality of the Call Forwarding

Unconditional Supplementary Service applied to all telecommunication services of remote party B for which CFU is

NOTE 1: the "served mobile subscriber" in 3GPP TS 22.094 [5] corresponds to the "remote party" in the present

document and the "forwarded-to subscriber" in 3GPP TS 22.094 [5] corresponds to the "initiating

NOTE 2: The forwarding of calls for remote party B to initiating subscriber A can be achieved by invoking the Call

Forwarding Unconditional Supplementary Service or by making use of an equivalent operator specific

The functionality of the control of Follow Me (registration, erasure, forced erasure and interrogation) is split between

the HLR of the initiating subscriber A (HLRa) and the FFN of the remote party B (FFNb).

FM can be registered / erased / interrogated by an initiating subscriber A with respect to a remote party B if both parties

To enable forced erasure by an FM service supervisor, the FM service shall be provisioned to the FM service

supervisor. Additionally, she needs the subscription entitlement to perform the forced erasure.

NOTE: In general remote party B does not correspond to a GSM subscriber. In this case provisioning of FM for

If remote party B is a GSM subscriber and if the forwarding of calls for remote party B to initiating subscriber A is

achieved by invoking the Call Forwarding Unconditional Supplementary Service, provision of CFU for remote party B

The initiating subscriber registers the FM feature with respect to a particular remote party.

If an initiating subscriber A successfully registers FM with respect to a remote party B then FM becomes registered,

As a result of the registration subsequent calls directed to remote party B are forwarded to initiating subscriber A.

If an initiating subscriber A or the FM service supervisor successfully erases FM with respect to a remote party B then

For forced erasure by the FM service supervisor the previously registered subscriber shall be informed of the successful

forced erasure via a network initiated USSD Notify message with appropriate contents. This message is sent by the

If remote party B is a GSM subscriber and successfully erases FM then FM becomes not registered and not active for

If an initiating subscriber A or the FM service supervisor successfully interrogates FM with respect to a remote party B

If remote party B is a GSM subscriber and successfully interrogates FM then this procedure interrogates her own FM

Figure 4.1 shows the Information Flow for the control of FM (registration, erasure, forced erasure and interrogation) by

For any control operation on FM, the initiating subscriber (MSa) enters a Follow Me Request (FM-Request). This is a

USSD string containing the requested FM operation and the remote number. The Follow Me Request is routed via the

The HLRa performs a series of checks as described in the SDLs (subclause 4.3). If these checks fail, the MSa receives a

If the checks pass, the HLRa forwards the operation request (HLR-FM-Request) to the FFN of the remote party (FFNb).

FFNb carries out the appropriate control operation and checks as described in the SDLs (subclause 4.3) for the remote

The result of this operation (success or error) is reported back in a USSD Response to the initiating subscriber.

For successful forced erasure by a service supervisor, the FFN shall send a Network Initiated USSD notify message

with the corresponding USSD string to the HLR of the previously registered subscriber who had registered the Follow

Me data. The HLR shall forward the USSD notify to VLR which will relay the USSD Notify towards the MS.

Upon receipt of the USSD Notify, the MS shall respond by sending a FACILITY message with empty return result

An error response with corresponding reason can be returned from any entity, when error happens at the entity 3GPP

Figure 4.1: Information flow for the control of FM by the initiating subscriber or service supervisor

NOTE 1: OR1:N: The case where the checks in the HLR result in a negative outcome, e.g. FM is not

provisioned for the initiating subscriber or the initiating subscriber is not allowed to

OR1:Y: The case where all the checks in the HLR are successful, e.g. FM is provisioned for the

initiating subscriber and the initiating subscriber is allowed to operate FM for the remote

SI Supervisor Indicator. This parameter is conditional and only used for forced erasure by a

PIM MSISDN of previously registered subscriber who has registered the FM to remote

number. This parameter is conditional and only used for forced erasure by a FM service

MSISDN-A initiating number in international format. It is not a part of the USSD string, but is sent

For forced erasure, the MSISDN-A corresponds to the supervisor’s MSISDN and will be

Control of FM by the remote party is possible if the remote party is a GSM subscriber.

The information flow for control of FM by the remote party (erasure and interrogation of her own FM data) is the same

If a remote party tries to register FM to herself the registration is rejected and an error is reported.

HLRa and FFNb can both receive FM control messages, based on USSD. The USSD handler in each entity analyses the

Service Code contained in the USSD string and, recognising the Service Code for FM, invokes the FM USSD

The FM USSD application in HLRa is the process FM_initiating_subscriber_handling_in_HLR (figure 4.2). It

receives the FM-Request from the initiating subscriber. This FM-Request is an USSD-string containing:

- whether any operator specific restrictions to engage in FM activity with the remote party apply;

- if the initiating subscriber requires forced erasure, the HLR checks Whether the initiating subscriber is entitled to

The basic MSISDN of the initiating subscriber is sent together with the original USSD string to the FFN of the remote

For successful forced erasure by a service supervisor, the HLR of the previously registered subscriber (HLRp) shall

relay the USSD Notify to the VLR when the USSD Notify from the FFN is received. The VLR will then forward the

On receipt of an USSD response from the MS of the previously registered subscriber, the HLRp shall relay it to the

If the FFN is an HLR, the FFN is responsible for handling the interactions between FM and CFU. Two kinds of request

When the control process in the FFN receives a CFU request, it shall either pass the CFU operation request directly to a

CFU process or reject it depending on the registration and/or activation states of both FM and CFU services (see Table

On receipt of an HLR-FM request, the control process in the FFN performs a series of FM specific checks and checks