1 Call Forwarding Unconditional

22.0823GPPCall Forwarding (CF) Supplementary ServicesStage 1TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

1.1 Definition

This service permits a called mobile subscriber to have the network send all incoming calls, or just those associated with a specific Basic service group, addressed to the called mobile subscriber’s directory number to another directory number. The ability of the served mobile subscriber to originate calls is unaffected. If this service is activated, calls are forwarded no matter what the condition of the termination.

1.2 Description

1.2.1 Description

The served mobile subscriber can request a different forwarded-to number for each Basic service group containing a basic service to which she has subscribed.

1.2.2 Applicability to telecommunication services

The applicability of this supplementary service is defined in 3GPP TS 22.004.

1.2.3 Terminology

A served mobile subscriber is a mobile subscriber of a particular PLMN access who is requesting that calls to her number be forwarded. This subscriber may also be referred to as the forwarding subscriber or the called subscriber.

A forwarded-to subscriber is a subscriber to whom the call shall be forwarded.

1.3 Normal procedures with successful outcome

1.3.1 Provision

The supplementary service will be provisioned for all Basic Services subscribed to and to which it is applicable.

The service can be offered with several subscription options. Options apply to all Basic services subscribed to. For each subscription option, only one value can be selected.

Subscription options Value

Calling subscriber receives No

notification the call has been forwarded Yes

MSISDN of the served subscriber can be No

presented to the forwarded-to subscriber Yes

1.3.2 Withdrawal

The service will be withdrawn at the subscriber’s request or for administrative reasons.

1.3.3 Registration

The following information has to be registered in the network:

1) the forwarded-to number, which may be accompanied by a forwarded-to sub-address;

2) information as to whether all calls or all calls of one (or several) specific Basic service groups should be forwarded.

If no Basic Service code is inserted by the user this is interpreted as All Basic Services.

Registration can take place either by the service provider or with an appropriate control procedure by the subscriber.

Verification, where possible, of the forwarded-to number should be accomplished before accepting the call forwarding request. This verification is done by a simple check of the forwarded-to number to see if the number is within the allowed number range.

When the mobile subscriber so registers call forwarding unconditional, the network will return notification of acceptance or rejection of the request. This notification will include the forwarded-to number to which call forwarding unconditional is registered.

1.3.4 Erasure

A previous registration can be erased in either of three ways:

Firstly, the subscriber can specifically erase a previous registration with an appropriate control procedure.

Secondly, the subscriber can register information for call forwarding unconditional for the specific Basic service group to another directory number, thus causing the previous registration of call forwarding unconditional to be overridden.

Thirdly, all information is erased as a result of withdrawal of the service.

1.3.5 Activation

The user shall be allowed to activate Call Forwarding Unconditional (CFU) by e.g. using the MMI command described in 3GPP TS 22.030. This activation request may include information of which Basic Service Group(s) it shall apply to. If no such information is included the Activation request applies to all Basic Service Groups.

When receiving an activation request the network shall activate CFU for the Basic Service Groups comprised in the BS group information given by the user against which a CFU forwarded-to-number is registered. The Activation(s) shall be in accordance with the rules set out in 3GPP TS 22.004.

When CFU is activated for Basic Service Group (Voice – MMI service code 11; Fax – MMI service code 13; Data – MMI service code 12) as defined in 3GPP TS 22.030 [3], a notification shall be sent to the user. Subsequently, when the UE is in idle mode, an indication may be given to the user to show that CFU for Basic Service Group Voice – MMI service code 11 is active.

The supplementary service is also activated for a Basic service group as a result of Registration for that Basic service group.

1.3.6 Deactivation

An active CFU can be deactivated in either of two ways;

– The user may deactivate CFU by means of an appropriate control procedure (e.g. as described in 3GPP TS 22.030). A deactivation request may contain information of which Basic Service Group(s) it shall apply to. If no such information is included the Deactivation request applies to all Basic Service Groups.

When receiving a deactivation request the network shall deactivate CFU for the Basic Service Group(s) comprised in the BS group information given by the user against which a CFU forwarded-to-number is registered. However, the registered information shall not be erased. The Deactivation(s) shall be in accordance with the rules set out in 3GPP TS 22.004.

Even if there is no data stored against a particular Basic Service group comprised in a deactivation request, the request shall be accepted by the network for the other Basic Service group(s) included in the information given by the user.

– The service is deactivated as a result of Erasure.

In the former case, and also in the latter if Erasure is user controlled, the user shall receive a notification of whether her request was accepted or rejected in accordance with the rules set out in 3GPP TS 22.004.

1.3.7 Invocation

If the supplementary service is activated for a Basic service incoming calls for the specified Basic service will be forwarded by network invocation.

1.3.8 Normal operation with successful outcome

When call forwarding unconditional is active and operative, incoming calls for the specified Basic Service(s) will be forwarded without being offered to the served mobile subscriber.

The forwarded-to subscriber will receive an indication that the call has been forwarded with the cause. The cause, when available, will be the appropriate forwarding condition. Depending on the value of the served subscribers subscription option, the forwarded-to subscriber may also receive the MSISDN of the served subscriber.

When multiple forwarding occurs the reason for forwarding and the MSISDN given to the forwarded-to subscriber should relate to the last forwarding subscriber in the chain.

When call forwarding unconditional is active and operative, the ability of the served mobile subscriber to originate calls is not affected. However, an indication that the call forwarding service is currently active and operative on a number will be given to the forwarding party each time an outgoing call is made.

As a subscription option, the served mobile subscriber can request that the calling subscriber receives a notification that the call has been forwarded.

NOTE: In case the notification is implemented using intermediate tones or announcements, the tones and/or announcements to the calling party should not be provided if the information transfer capability is set to UDI.

1.3.11 Interrogation

Data request

The data request procedure enables the mobile subscriber to obtain information about the data stored in the PLMN. After having requested this procedure the network shall return the following information:

– in response to a general data request the served mobile subscriber should be given a list of all Basic service groups to which call forwarding unconditional is registered, including information whether or not it is active and operative, and the associated forwarded-to numbers;

– in response to a specific request concerning one particular Basic service group, the served mobile subscriber should be informed whether or not call forwarding unconditional is registered, including information whether or not it is active and operative for that Basic service group. If CFU is registered, the associated forwarded-to number shall be given.

1.3.12 Charging requirements

The forwarding subscriber may be charged for the forwarded part of the call.

1.4 Exceptional procedures or unsuccessful outcome

1.4.2 Registration

If the system cannot accept a registration request, the served mobile subscriber should receive a notification that call forwarding unconditional registration was not successful. Possible causes are:

– service not subscribed to;

– forwarded-to number is invalid directory number;

– use of an operator access prefix;

– insufficient information;

– forwarded-to number is a special service code (e.g. police);

– forwarded-to number is the directory number of the mobile subscriber herself;

– conflicting situation with other supplementary services (e.g. incoming call barring has been activated);

– no basic service provisioned within the basic service group(s).

The network is not required to validate information related to the forwarded-to number.

1.4.3 Erasure

If the network cannot accept a mobile subscriber’s request for erasure, cause will be returned to the subscriber, such as:

– insufficient information;

– inconsistent with registration.

If the subscriber does not completely specify which call forwarding unconditional request is to be erased, the network will reject the erasure request with appropriate cause.

If no Basic Service Code is inserted by the user, CF will be erased from all Basic Services.

1.4.4 Activation

If there is no CFU forwarded-to-number registered against a Basic Service group, the activation request for that Basic Service group shall be denied.

Examples of causes for a not accepted activation request:

– service not provisioned;

– conflicting situation with other supplementary services;

– service not registered.

1.4.5 Deactivation

If the network cannot accept a deactivation request, an appropriate cause will be returned to the user, e.g. Service not Active.

1.4.6 Invocation

Within a PLMN or different PLMNs the number of tandem forwarding connections should be limited. The maximum number of tandem forwarding connections should be limited to a value between 1 and 5. This is to prevent infinite looping.

If the limit of successive forwardings of a call has already been reached, an unsuccessful call set up indication is sent backwards.

If the forwarded call cannot be completed to the forwarded-to destination, then the network will clear the forwarded part of the call and an unsuccessful call set up indication is sent backwards.

NOTE: Call forwarding unconditional applies only to the Basic services subscribed to. Calls to a directory number requesting a Basic service which is not subscribed to will never be forwarded.

1.5 Alternate procedures

None identified.

1.6 Interactions with other supplementary services

1.6.81.1 Calling line identification presentation

See 3GPP TS 22.081.

1.6.81.2 Calling line identification restriction

See 3GPP TS 22.081.

1.6.81.3 Connected line identification presentation

See 3GPP TS 22.02.81.

1.6.81.4 Connected line identification restriction

See 3GPP TS 22.02.81.

1.6.82.2 Call forwarding on mobile subscriber busy

If Call forwarding unconditional is active, activation of Call forwarding on mobile subscriber busy is rejected. The served mobile subscriber shall be informed of this supplementary service incompatibility.

If Call forwarding on mobile subscriber busy is active, activation of Call forwarding unconditional will be accepted. Call forwarding on mobile subscriber busy will be quiescent during the active period of Call forwarding unconditional. If Call forwarding unconditional is subsequently deactivated, Call forwarding on mobile subscriber busy becomes operative again (unless the interaction with another supplementary service requests that it remains quiescent).

If Call forwarding unconditional is active for one particular basic service, activation of Call forwarding on mobile subscriber busy for all basic services is rejected. The served mobile subscriber shall be informed of this supplementary service incompatibility.

If Call forwarding on mobile subscriber busy is active for one particular basic service, activation of Call forwarding unconditional for all basic services will be accepted. Call forwarding on mobile subscriber busy will be quiescent during the active period of Call forwarding unconditional. If Call forwarding unconditional is subsequently deactivated, Call forwarding on mobile subscriber busy becomes operative again (unless the interaction with another supplementary service requests that it remains quiescent).

1.6.82.3 Call forwarding on no reply

Same as interaction between Call forwarding unconditional and Call forwarding on mobile subscriber busy.

1.6.82.4 Call forwarding on mobile subscriber not reachable

Same as interaction between Call forwarding unconditional and Call forwarding on mobile subscriber busy.

1.6.83.1 Call waiting

See 3GPP TS 22.083.

1.6.84.1 Multi party

See 3GPP TS 22.084.

1.6.85.1 Closed user group

See 3GPP TS 22.085.

1.6.86.1 Advice of charge

See 3GPP TS 22.086.

1.6.88.1 Barring of all outgoing calls

Served mobile subscriber:

– If barring of all outgoing calls is active, the registration and/or activation of call forwarding unconditional is denied. The mobile subscriber requesting for this call forwarding service shall be informed of this supplementary service incompatibility.

– If Call forwarding unconditional is active, activation of Barring of all outgoing calls is denied. The mobile subscriber shall be informed of this supplementary service incompatibility.

1.6.88.2 Barring of outgoing international calls

Served mobile subscriber:

– If barring of outgoing international calls is active, the registration of an international forwarded-to number (from the home PLMN country) for call forwarding unconditional, as well as the activation of call forwarding unconditional to such a forwarded-to number, is denied. The mobile subscriber shall be informed of this supplementary service incompatibility.

– If Call forwarding unconditional is active to an international forwarded-to number (from the HPLMN country), activation of Barring of outgoing international calls is denied. The mobile subscriber shall be informed of this supplementary service incompatibility.

1.6.88.4 Barring of outgoing international calls except those directed to the home PLMN country

Same as interaction between Call forwarding unconditional and Barring of outgoing international calls.

1.6.88.6 Barring of all incoming calls

Calling subscriber: No interaction

Served mobile subscriber:

– If barring of all incoming calls is active, the registration and/or activation of call forwarding unconditional is denied. The mobile subscriber shall be informed of this supplementary service incompatibility.

– If Call forwarding unconditional is active, activation of Barring of all incoming calls is denied. The mobile subscriber shall be informed of this supplementary service incompatibility.

Forwarded-to subscriber: Calls forwarded to a subscriber having Barring of all incoming calls active, will be denied as any other incoming call to that subscriber.

1.6.88.7 Barring of incoming calls when roaming outside the home PLMN country

Served mobile subscriber:

– If Barring of Incoming Calls when Roaming Outside the HPLMN Country is active, registration and/or activation of Call Forwarding Unconditional is permitted and Barring of Incoming Calls when Roaming Outside the HPLMN Country becomes quiescent.

– If Call Forwarding Unconditional is active, activation of Barring of Incoming Calls when Roaming Outside the HPLMN Country is not permitted. The mobile subscriber shall be informed of this supplementary service incompatibility.

Forwarded to subscriber: Calls forwarded to a subscriber having Barring of incoming calls when roaming outside the HPLMN country active and operative, will be denied as any other incoming call to that subscriber.

1.6.88.8 Anonymous Call Rejection

See 3GPP TS 22.088 [9].

1.7 Interworking considerations

If the forwarded-to number is not a PLMN- or ISDN-number, then an interworking situation is said to exist.

If a forwarded call meets an interworking situation, then an interworking indication should be sent to the calling party. When interworking with non-PLMN or non-ISDN networks, tones and announcements will be required.

NOTE1: The number of times a call has been forwarded once it has exited the PLMN or ISDN may not be limited.

NOTE2: Tones and/or announcements should not be provided to the calling party if the information transfer capability is set to UDI.