4.1 General

23.0943GPPFollow-Me (FM)Release 17Stage 2TS

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 a different initiating subscriber for the Follow Me application.

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

The present document deals with the control operations of FM in HLRa and FFN. If the FFN is an HLR, the control of the requests for both FM and CFU services is specified (see clause 4.3.2).

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 applicable.

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 subscriber" in the present document.

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 service (e.g. via CAMEL).

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).

4.1.1 Provision

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

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 remote party B is operator specific.

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 is required.

4.1.2 Registration

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, active and operative for remote party B.

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

NOTE: The remote party cannot register FM with respect to herself.

4.1.3 Erasure

If an initiating subscriber A or the FM service supervisor successfully erases FM with respect to a remote party B then FM becomes not registered and not active for remote party B.

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 FFN.

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

4.1.4 Interrogation

If an initiating subscriber A or the FM service supervisor successfully interrogates FM with respect to a remote party B then this procedure interrogates the FM data of subscriber B.

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