3GPP system architecture evolution (SAE): Report on technical options and conclusions
The objective of this feasibility study is to develop a framework for an evolution or migration of the 3GPP system to a higher-data-rate, lower-latency, packet-optimized system that supports, multiple RATs. The focus of this work will be on the PS domain with the assumption that voice services are supported in this domain.
NOTE: This feasibility study has led into work items specifying LTE/SAE and the contents of this study should be considered out of date.
The main objectives are to address the following aspects:
1) Overall architecture impacts stemming from requirements coming out from TSG-RAN's Study Item on Radio Evolution (see SP‑040915). The architectural developments should take into account the targets for the evolution of the radio-interface, e.g.:
i) whether there is a need for a modified network architecture and/or different functional split between network nodes (compared to the current 3GPP architecture);
ii) how to provide a very low latency (including C-plane) for the overall network (including core network, radio access network and radio access technology);
iii) how to provide the efficient support of the various types of services, especially from the PS domain (e.g. Voice over IP, Presence).
2) Overall architecture impacts stemming from the work in SA1 on an All-IP Network (AIPN) (see TS 22.258 [4]), e.g.:
i) support of a variety of different access systems (existing and future) and access selection based on combinations of operator policies, user preferences and access network conditions;
ii) how to realize improvements in basic system performance e.g. communication delay, communication quality, connection set-up time, etc.;
iii) how to maintain the negotiated QoS across the whole system; in particular to address inter-domain and inter-network interworking, and, QoS on the network link to the Base Station site.
NOTE: Although used in the SA WG1 TS 22.258 [4], the All-IP Network (AIPN) term is not used in the network architecture in this SAE TR as mapping between the term AIPN used in SA1 and the evolved architecture is not deemed necessary to progress the SAE work. Instead, the requirements on AIPN in TS 22.258 [4] are treated as overall system requirements. Even though the AIPN includes an evolved, IP based, core network and evolved IMS domain, the scope of this SAE TR does not include the IMS domain aspects.
3) Overall architecture aspects of supporting mobility between heterogeneous access networks, including service continuity. E.g.:
i) service continuity between I-WLAN and the 3GPP PS domain;
ii) how to support multiple radio access technologies and terminal mobility between different radio access technologies;
iii) how to maintain and support the same capabilities of access control (authentication, authorization), privacy and charging when moving between different radio access technologies.
Migration aspects should be taken into account for the above, i.e. how to migrate from the existing architecture.
In the course of conducting this feasibility study additional individual Work Items may be identified and prepared to address certain aspects and to take care of the respective specification work. The timelines of those Work Items may or may not concur with the timeline of this feasibility study.