Page 266 - 5G Basics - Core Network Aspects

1 Core network aspects

Appendix I

The evolvement of multi-connection architecture
(This appendix does not form an integral part of this Recommendation.)

The multi-connection architecture facilitates advanced networking with pervasive accessibility and high
reliability, accumulative access bandwidth and economical operating expenditure (OPEX) and capital
expenditure (CAPEX). It is assumed that there are four stages for introducing multi-connection architecture
into current networks:
Stage 1: UE enhanced for multi-connection

Current multi-mode terminals support employing more than one access technology simultaneously
(e.g., smartphones). Actually, it is common all over the world that an ordinary smartphone can support
multiple access modes such as GPRS and Wi-Fi at the same time. Apparently, the key problem for UEs in this
period is not to find and attach to an available access any longer, but to avoid two events: The first is that
users have to manually choose expected networks in complicated, even unpredicted, access environments;
the second is that services would be frequently interrupted by accidental changes of access. For these
reasons, it is required to improve QoE in access selection and service continuity, such as keeping online
gaming alive while answering a call, shifting traffic among GPRS/UMTS/WLAN, etc. It is possible to solve those
problems simply by an enhanced device such as an MUE.
In this stage, a certain function, such as a connection manager (as an implementation of MTC-FE), is
recommended to be supported in various terminals. The improvement is that users' preference for network
accessing methods can be recorded and automatically enforced in MUEs. The MUE is recommended to
support the transfer multi-connection messages with any other devices.
Stage 2: Multi-connection signalling introduced between terminals and networks

The introduction of multi-connection signalling allows MUEs to exchange access policies and status with
heterogeneous networks. The distinguished networks are recommended to do AAA independently, traffic
control, QoS, charging, etc. It is too complicated to enhance MUE to support both gathering all the possible
connection information and making the perfect decision with little knowledge of the status of each access. It
is reasonable for the network to provide a common access policy to guide MUEs to multi-connection service.

In this stage, functions similar to MR-FE and/or MPC-FE would be set into the network to assign pre-
configured multi-connection policy to MUEs. Users would mainly benefit from statistical optimization by the
network without detecting access statuses.

Stage 3: Various multi-connection solutions accepted by the public
In stage 3, some enterprises/operators/ISPs would tend to introduce required functions for their own
purpose to profit from load-balancing, high reliability, accumulative bandwidth, etc. For example, MC-FE and
MMF are recommended to be deposed to offload traffic in some specific networks to encourage operators
to fulfil individual preferences as well as to limit the investment in legacy network elements. Or it is
recommended to use MAS-F and SCF functions to provide multi-connection based services to users.

Stage 4: Multi-connection architecture evolvement implemented
In the final stage, the whole multi-connection architecture would be implemented across heterogeneous
networks. The existing networks can be reused without further modification. Users and network operators
would gain a win-win relationship by enjoying the harmony of ambulant network resources.

The evolvement of multi-connection architecture would achieve two targets: The first is that the services
would intelligently select and utilize heterogeneous network resources without user intervention; the second
is the flexibility obtained by having multiple networks exchange either a single flow or a group of traffic flows.

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