5 Functional requirements

22.1353GPPMulticallRelease 17Service descriptionStage 1TS

5.1 Provision

Multicall is provided by prior arrangement with the service provider.

Multicall shall be provisioned for all Basic Services (BS) subscribed to and to which it is applicable, i.e. not to any subset of these BS.

When the Multicall supplementary service is provisioned the maximum number of simultaneous CS beares available to the subscriber (N_br_SB) shall be defined as part of the subscription. The value for N_br_SB shall in the range from 2 up to 7.

5.2 Withdrawal

It shall be possible to withdraw the Multicall supplementary service subscription on request of the subscriber or for administrative reasons.

5.3 Registration

The user shall be able to modify the maximum number of CS bearers available (N_br_User) within the limitations set by the service provider. (N_br_SB).

If the subscriber attempts to register a value for N_br_User that is higher than the value of N_br_SB, the request shall be rejected and the subscriber shall be informed on the unsuccessful outcome on the request.

5.4 Erasure

Data related to the Multicall supplementary service shall be erased by the service provider as a result of withdrawal.

5.5 Activation

The Multicall supplementary service shall be activated by the service provider as a result of provision.

5.6 Deactivation

The Multicall supplementary service shall be deactivated by the service provider as a result of withdrawal.

5.7 Invocation

The Multicall supplementary service shall be invoked by the system when at least one call is in progress and another call with a dedicated bearer is to be set up. The Multicall service applies to mobile originating and mobile terminating calls.

5.8 Interrogation

The user shall be able to interrogate the network for the values of N_br_User, N_br_SB and N_br_SN.

5.9 Call related procedures

5.9.1 Terminating CS call

The indication of a terminating CS call to the mobile terminal will be done by the Multicall supplementary service until either the maximum number of bearer (N_br) or the maximum number of CS mobile terminating calls (N_{cs_}MT) has been reached.

If the maximum number of terminating calls (N_cs_MT) has been reached, and additional terminating call shall be reject without any indication to the subscriber.

If the maximum number of bearers (N_br) has been reached an additional terminating call will be only indicated to the user if the user has the Call Waiting supplementary service active, see chapter 7.4.2 for interactions with Call Waiting.

If N_br and N_cs_MT havenot been reached, a terminating call is indicated to the user and she may react in the following way:

a) Accept the terminating call:

– The user/user applications shall have the possibility to allocate a new bearer for the terminating call.

– If the user has the Call Hold SS active, the user shall have the possibility to reuse/share an already established bearer (e.g. release existing calls or put an speech on hold and accept the terminating call).

b) Rejecting the terminating call:

– If the user rejects the terminating call the call shall be released in a normal way.

c) Ignore the incoming call:

– If the user ignores the indication of the terminating call (i.e. neither accepts nor rejects it ), the normal call handling shall apply, e.g. after the Alerting Timer expires the call will be released.

If there is a terminating speech call attempt and an ongoing speech call (active or held), the terminating call shall not be indicated to user by the Multicall service. The Call waiting call SS shall be invoked if applicable, see chapter 7.4.2 for interactions with Call Waiting SS.

The user can have possibility to reuse/share a bearer only when she is provisioned for Call Hold SS. See subclause 7.4.1 for interaction with Call Hold SS.

5.9.2 Originating CS call

If neither N_br nor N_cs_MO have not been reached and the user wants to establish a new originating CS call she may act in the following way:

1. allocate a new bearer for the originating call;
2. reuse/share an already established bearer (e.g. to put an speech on hold and set-up a new call).

The user can have possibility to reuse/share a bearer only when she is provisioned for Call Hold SS. See subclause 7.4.1 for interaction with Call Hold SS. The mobile terminal shall not originate a speech call requesting a new bearer when there is already an active speech call.

5.10 Charging requirements

Each of the calls using a dedicated bearer shall be charged individually.

Allocation of a dedicated bearer shall be visible in the charging data.