Since a phased approach has been adopted, the same general service principles shall apply to each phase. Support of services from an end user perspective is understood to be an important driver for established mobile users to stay with their existing operator while taking the new services into use. It is therefore important to enable operators to offer continued support of legacy services in future releases. Previous release services shall as a principle also be supported in the following releases.
Networks shall be capable of providing a specified core set of capabilities.
The core set of capabilities should permit home environment to offer a range of distinctive services including those which cannot be implemented on systems based on previous release specifications.
It shall be possible for the home environment to develop services with full roaming capability.
The radio interface should not unnecessarily restrict the development of new services (within physical limitations).
The standard shall provide a mechanism which allows a terminal to be easily upgraded so that it can access new services which are within the physical limitations of the terminal.
In the CS CN domain, the basic services are divided into circuit teleservices (TS 22.003) and bearer services (TS 22.002) and they can utilise standardised supplementary services (TS 22.004).
The PS CN Domain provides IP bearer services. SMS, USSD and UUS can also be considered as bearer services for some applications.
IP multimedia services are the IP based session related services, including voice communications. IP multimedia sessions use IP bearer services provided by the PS CN Domain.
Value added non-call related services include a large variety of different operator specific services/applications. They are usually not specified by 3GPP. The services can be based on fully proprietary protocols or standardised protocols outside 3GPP.
In order to create or modify the above services (both call and non-call related services) operators may utilise toolkits standardised by 3GPP (such as CAMEL or LCS) or external solutions (e.g. Internet mechanisms). Pre-paid is an example of an application created with toolkits that may apply to all of the above services categories.
3GPP specifications shall enable the user of a single terminal to establish and maintain several connections simultaneously. It shall efficiently cater for applications which have variable requirements relating to specific QoS parameters (e.g. throughput) whilst meeting other QoS targets. It shall also cater for applications which are able to take adapt to a range of variations in QoS.
3GPP specifications shall support development of multimedia services and provide the necessary capabilities.
Multimedia services combine two or more media components (e.g. voice, audio, data, video, pictures, text) within one call. A multimedia service may involve several parties and connections (different parties may provide different media components) and therefore flexibility is required in order to add and delete both resources and parties.
Multimedia services are typically classified as interactive or distribution services.
Interactive services are typically subdivided into conversational, messaging and retrieval services:
Conversational services are real time (no store and forward), usually bi-directional where low end to end delays (< 100 ms) and a high degree of synchronisation between media components (implying low delay variation) are required. Video telephony and video conferencing are typical conversational services."
Messaging services offer user to user communication via store and forward units (mailbox or message handling devices). Messaging services might typically provide combined voice and text, audio and high-resolution images.
Retrieval services enable a user to retrieve information stored in one or many information centres. The start at which an information sequence is sent by an information centre to the user is under control of the user. Each information centre accessed may provide a different media component, e.g. high resolution images, audio and general archival information.
Distribution services are typically subdivided into those providing user presentation control and those without user presentation control.
Distribution services without user control are broadcast services where information is supplied by a central source and where the user can access the flow of information without any ability to control the start or order of presentation e.g. television or audio broadcast services.
Distribution services with user control are broadcast services where information is broadcast as a repetitive sequence and the ability to access sequence numbering allocated to frames of information enables the user (or the user's terminal) to control the start and order of presentation of information.
CS multimedia call is a Bearer Service which utilises Synchronous Transparent Data service. The following basic requirements shall be supported for CS multimedia calls :
CS multimedia call shall be based on a 3GPP specific subset of H.324M.
All call scenarios shall be supported, i.e. Mobile Originating and Mobile Terminating call against Mobile, ISDN and PSTN call party.
Single and multiple numbering schemes shall be supported.
Fallback to speech (TS 11 ) shall be supported from 3.1kHz Ext. PLMN multimedia bearer, i.e. if setup of the multimedia call fails the call will be set up as a speech call.
Service change and fallback shall be supported for UDI/RDI multimedia bearer and speech, to allow fallback to a less preferred service if the preferred service is unsupported, and to change the service between speech and multimedia during the call.
In the case where a CS multimedia call includes speech (e.g. video call) then the following requirements apply:
A user shall be able to change between a speech and CS multimedia call, when desired.
When the CS multimedia call is no longer supported, for example due to degraded coverage conditions (including UTRAN to GERAN only transitions), service change shall occur automatically from a CS multimedia call to speech.
When a CS multimedia call can be supported, for example due to improved coverage conditions (including GERAN only to UTRAN or UTRAN/GERAN transitions), service change back to the CS multimedia call may be initiated by the network.
Other services than CS multimedia call may exist which utilise the Synchronous Transparent Data service. Service transition to/from speech described for CS multimedia call in this clause shall only apply to CS multimedia call and not Synchronous Transparent Data services in general.
Different bitrates as specified at TS 22.002 shall be supported.
Supplementary services apply to multimedia calls as for Synchronous Transparent Data service according to TS 22.004.
When accepting a multimedia call, the user shall be able to request a service change to speech before the call is answered, such that the multimedia path is never actually connected through to the user's phone.
The user shall be able to deny a service change to multimedia during the call.
IP multimedia services are not the evolution of the circuit switched services but represent a new category of services, mobile terminals, services capabilities, and user expectations. Any new multimedia service, which may have a similar name or functionality to a comparable standardised service, does not necessarily have to have the same look and feel from the user's perspective of the standardised service. Voice communications (IP telephony) is one example of real-time service that would be provided as an IP multimedia application.
The following basic requirements are be supported for IP multimedia :
IP multimedia session control shall be based on SIP .
All session scenarios shall be supported; i.e. Mobile Originating and Mobile Terminating sessions against Internet/Intranet, CS or IM Mobile, ISDN, PSTN call party.
MSISDN and SIP URL numbering and addressing schemes shall be supported.
IP multimedia applications shall as a principle, not be standardised, allowing service provider specific variations.
Real-Time Text (RTT) conversation is a service enabled in 3GPP networks by the Global Text Telephony ( GTT ) .
GTT enables real time, character by character, text conversation to be included in any conversational service, Circuit Switched as well as IP based.
It is possible to use the text component in a session together with other media components, especially video and voice.
Interworking with existing text telephony in PSTN as well as emerging forms of standardised text conversation in all networks is within the scope of this feature.
The text media component can be included initially in the session, or added at any stage during the session.
The text component is intended for human input and reading, and therefore supports human capabilities in text input speed. The character set support is suitable for the languages the users communicate in.
GTT specifies limited interoperation with Multimedia Messaging Services including a possibility to divert to messaging in case of call failure and sharing user interface equipment and external UE interfaces.
3GPP specifications shall include standardised protocols enabling service management. It shall enable control, creation and subscription of service capabilities and services, and the management of user profiles.
The home environment should be automatically notified when a user, identified by a SIM/USIM, has changed ME and should be informed of the identity of the new ME. This should be applicable to any ME. It should also be possible to achieve Automatic Device Detection for users using any SIM/USIM.
The notification that a user has changed ME shall be given as early as possible.
A number of bearers shall be provided that can differ in flexibility and offer different capabilities. Bearers may be characterised by parameters such as "throughput", "delay tolerance", "maximum bit error rate", "symmetry" etc. These bearers enable information to be transferred appropriate to the provision of teleservices, multimedia services and end user applications generally, via subnetworks which typically provide different specified qualities of service.
The assignment and release of bearers is provided by the bearer control function. Provision should be made for several bearers to be associated with a call and for bearers to be added to a call and/or to be released from a call following call establishment. The bearers should be independent of radio environments, radio interface technology and fixed wire transmission systems.
Adaptation/Interworking functions are required in order to take account of the differences between the bearers used for the provision of a teleservice/multimedia service/application in the fixed network and the bearers. Adaptation/Interworking functions are required which take account of the discontinuous and/or asymmetrical nature of most teleservices/multimedia services/applications.
The service platform shall provide interfaces (to serving networks and home environments) appropriate to the support, creation and control of supplementary services, teleservices, multimedia services and user applications. The service platform will also provide interfaces enabling subscribers to control supplementary services, teleservices, multimedia services and user applications.
Supplementary service provision and control will be independent of radio operating environment, radio interface technology and fixed wire transmission systems.
As far as possible, the service platform is required to enable new supplementary services, teleservices, multimedia services and/or end user applications to be supported at minimum cost, with minimum disruption of service and within the shortest possible time.
The Quality of Service (QoS) parameters should be identified together with appropriate parameter values which set targets to be reached when designing 3GPP specifications, and which also will serve as guidelines for network design and service provision.
The QoS for call set-up time, as an example, can be defined in terms of a mean value and as a percentage of cases which should not exceed a certain time limit. Further information can be found in TS 22.105.
The performance requirements for the All-IP Network can be found in TS 22.278.
For UE initiated QoS control OMA device management shall be the primary method for provisioning QoS parameters.