4 Service description

22.1733GPPIP Multimedia Core Network Subsystem (IMS) Multimedia Telephony Service and supplementary servicesRelease 17Stage 1TS

4.1 General Service characteristics

The IMS Multimedia Telephony Service should allow multimedia conversational communications between two or more users. It provides real time bidirectional conversational transfer of speech, video or optionally other types of data.

The IMS Multimedia Telephony communication is point to point between terminals communicating, or a terminal and a network entity. This communication is usually symmetrical, but in special cases the media components present in each direction may be different, or they may be the same but with different bit rates and Quality of Service.

An IMS Multimedia Telephony communication can start with only one type of media and additional types of media may or may not be added by the users as the communication progress. Therefore a particular IMS Multimedia Telephony communication may consist of only one type of media, e.g. speech.

IMS Multimedia Telephony service is different from other IMS based services, such as Push to Talk over Cellular (PoC).
Its characteristics includes the following:

– IMS Multimedia Telephony is a service where speech, and speech combined with other media components, is the typical usage but the service is not limited to always include speech, it also caters for other media or combinations of media (e.g. text and video).

– The IMS multimedia telephony service includes supplementary services. The behaviour of these services is almost identical to supplementary services for CS voice (TS 11) and PSTN/ISDN.

NOTE: most supplementary services are active in the set-up phase. Mid-session supplementary services such as session transfer and session hold exist.

– The anticipated usage model is that of traditional telephony: one user connecting to any other user, regardless of operator and access technology.

– When a supplementary service is invoked it applies to all media components of an IMS Multimedia Telephony communication. A supplementary service can be activated by the user for one or more types of media components. If one or more of these media components are present in the IMS Multimedia Telephony communication then the supplementary service is invoked.

4.2 Default media handling capabilities of IMS Multimedia Telephony service

IMS Multimedia Telephony can support many different types of media.

IMS Multimedia Telephony service includes the following standardized media capabilities:

– Full duplex speech;

– Real time video (simplex, full duplex), synchronized with speech if present;

– Real-Time Text communication;

– File transfer;

– Video clip sharing, picture sharing, audio clip sharing. Transferred files may be displayed/replayed on receiving terminal for specified file formats

– Fax;

– Data (CS).

The support of each of these media capabilities is optional for a UE.

At least one common standardized format (e.g. JPEG, AMR) shall be supported per media type.

NOTE: IMS Multimedia Telephony service fulfils the service requirement for the Total Conversation in ITU-T F 703 [11].

The IMS Multimedia Telephony service shall support the following handling of media

– Adding, removing and modifying individual media to/from an IMS Multimedia Telephony communication

4.3 Association of Services to Time/Date

As a service option, the activation, deactivation and invocation of services may be associated with a time and/or date setting. To support roaming, the time zone may also be included.

4.4 Additional timing information

As a service option, additional timing information on current active services may be made available by the network. The content of this information is service dependant.

As a service option, the user may be allowed dynamically extend this timing for the active communication.

4.5 Allow / block list

As service provider option, activation/deactivation/invocation services may be associated with a allow/block list. A list may be specific to a service or may be used by several services.

4.6 Multi-device and Multi-Identity

4.6.1 General

The support of multiple devices is inherent in IMS. In addition, a service provider may allow a user to use any public user identities for its outgoing and incoming calls. The added identities can but do not have to belong to the served user. Identities may be part of different subscriptions and different operators.

NOTE: The identity does not have to be pre-allocated to an individual USIM or ISIM.

The owner (e.g. individual subscriber, operator/company) of the added identity needs to give its permission for others to use the identity.

The owner (e.g. individual subscriber, operator/company) of the identity shall be able to revoke the permission for others to use the identity.

A user shall be able to indicate which of the allowed identities the user wishes to use for each outgoing communication.

The network shall be able to indicate to the user which identity the incoming communication is intended to reach.

The network shall allow users to add and to delete identities asymmetrically, e.g. if an identity belonging to user B is allowed to be used by user A, this does not automatically mean that an identity belonging to user A is allowed to be used by user B.

Synchronization of communication logs between the multiple devices that are registered under the user identity shall be possible, e.g. the list of in- and outgoing calls, as well as when a missed call notification has been read on one device the other devices shall be updated so they are aligned.

4.6.2. User Configuration

The 3GPP System shall support a mechanism for an authorised user to set user preferences to indicate which identities are active or inactive on a specific UE

When an identity is activated or deactivated all UEs that can use that identity to either originate or terminate a session shall receive a notification of the change of status.

4.7 Caller Identity Verification Results Delivery to the User

The OIP service (including delivery of the calling name) and the eCNAM service deliver identity information based on information generated by the originating network (e.g., telephone number). Caller Identity Verification functions, such as Caller Identity Analytics functions at the terminating network, can modify the originating network’s caller identity information in accordance with the terminating operator policy. The modified name is intended to provide information to the end user about the potential risks associated with the caller identity.

Full or partial name string modifications that result from or are performed by the Caller Identity Analytics function shall be delivered to the UE, according to local operator policy.

Example displays:

– J. Smith

– "SCAM?" J. Smith

– "POSSIBLE SCAM".

This is primarily intended for situations where the existing device is unable to, otherwise, present new information to the user, such as spoofing indications.

The 3GPP system shall support a mechanism for a user to simply retrieve (e.g., to view or save) the full or partial name string delivered to the UE, including modifications that result from or are performed by the Caller Identity Analytics function.

NOTE: This applies to both answered calls and missed/unanswered calls (which are received but not answered due to call waiting or other reasons, including some calls rejected by the user intentionally).