Page 434 - 5G Basics - Core Network Aspects

1 Core network aspects

10 Network environment

10.1 General network environments

FMC needs to cover the possibilities for convergence across existing different network infrastructures and
access mechanisms.
The following are among the envisaged network infrastructures:
• Fixed network, such as PSTN/ISDN, cable TV network, softswitch-based/IMS-based PES, IPTV service
network, H.323 VoIP network and IMS-based NGN.
• Mobile network, multiple IMT-2000 family members consisting of the various releases of GSM
evolved UMTS core network with UTRAN access network [ITU-T Q.1741], the various releases of
ANSI-41 evolved core network with cdma2000 access network [ITU-T Q.1742], mobile WiMAX, etc.

The following are among the envisaged access mechanisms:
• The access network parts of IMT-2000: GSM/UTRAN and ANSI-41/cdma2000.
• WLAN in hot spots or as mesh networks.
• WiMAX broadband wireless access.
• xDSL, Cable, PLC, FTTH fixed access.

• Legacy PSTN systems used for narrow-band IP services access.
• The access network parts of digital audio broadcast (DAB) and digital video broadcasting
(DVB)/digital video broadcasting handheld (DVB-H).

NOTE – The various systems listed above encompass very different network infrastructures, different bandwidth
capabilities, as well as very different access technologies. It is therefore not anticipated that a single multimode terminal
device will be able to handle every possible access. Rather, it is anticipated that users will access their services via a
range of terminal devices, some of them capable of multimode operation. Consequently, mobility across this
heterogeneous environment requires service adaptation for terminal device mobility as well as for personal mobility.

10.2 FMC network scenarios
The following subclauses describe several scenarios for fixed-mobile convergence and indicate requirements
associated with these scenarios.

10.2.1 IMS-based FMC
This convergence of fixed and mobile networks enables users to move between fixed and mobile access
networks and still have access to the same set of IMS-based services. The fixed and mobile access networks
might both be part of the user's home network, but it is a requirement that the case where one or both are
visited networks is also supported.
IMS-based FMC includes the scenario that during mobility, only one access is on an IMS-based network.
Service continuity needs to be supported between the fixed and the mobile access technologies if the session
control layer corresponding to one of the access technologies is IMS-based (i.e., handover of voice calls
between the mobile circuit domain and the fixed network controlled by IMS).

Service provisioning is required to be independent of the access technologies.
User experience may be limited by the access network capabilities when using different access technologies,
such as lower quality video communication when low bandwidth access is used, etc.
ISIM functionalities are required for user identification mechanisms, but it is also necessary to support legacy
terminal devices without ISIM functionality for service access, especially when one side is not IMS-based
network.
Broadcasting/Multicasting capabilities are needed but may be limited by the network capabilities.

Access-agnostic uniform mechanisms are required; the end user could access the services from broadband
fixed-access (e.g., xDSL, cable) and mobile access (e.g., WiMAX).

424