Page 336 - 5G Basics - Core Network Aspects

1 Core network aspects

For example, in the video conference, the voice is transmitted by 2G, 3G, or LTE to assure real-time service,
and the video is transmitted by WLAN; both of these two access networks use the same core network. Data
flows can also be transmitted over the combined bit rate of the multiple access network connections to
increase throughput.

For example, the user is downloading a multi-media file with a large volume of data. To improve the
downloading rate and to balance the data downloading, the user accesses additional access network
connections to increase the bit rate.
4) Scenario D

In this scenario, a UE connects to multiple heterogeneous access networks controlled by separate access
control and service control functions. The UE and network combine the different flows at the application
layer.

For example, Sophie has dialled into an application providing unified communications to her company over
an LTE network. She indicates to the application the need to share a media presentation. The application
coordinates Sophie's UE to simultaneously use WLAN for the file sharing component.
5) Scenario E
In this scenario, a UE connects to multiple heterogeneous access networks through multiple access points,
which are controlled by separate access control and service control functions for different applications. In
this scenario, a specific application is bound to use a specific network connection. A UE can be treated as a
set of single-interface UEs which support different access technologies and utilize various applications
respectively, but service transfer between different connections should be considered in this scenario.

For example, if the UE connects to the company intranet through a virtual private network (VPN) connection
over WLAN, and the user wants to monitor the stock market as well, which is not allowed on the intranet, it
is necessary to use the 2G connection to access the stock application at the same time.

The following subclauses identify the requirements for multi-connection capability. These requirements
address UE requirements as well as network requirements.

6.1 Connection management

The connection management capability is used by a multi-connection UE and a multi-connection capable
network to establish, release, and modify connections. The capability is required to manage all connections
in their entirety to provide unified control to support the multi-connection use cases described in [b-ITU-T Y-
Sup.9], e.g. load balance.
NOTE – Connection management is different from the traditional resource management supported in single-connection
networks.
6.2 Multi-connection registration

In the multi-connection environment, a UE with multi-connection capability is required to register to the
multi-connection capable network. The following is also required:
1) A multi-connection UE is required to de-register all active connections of a given service when
terminating this service.

2) Access network information (i.e., attributes) is required to be provided to the core network during
the registration procedure.
3) A multi-connection identifier unique in the UE scope is required to identify each connection
belonging to the same UE.

6.3 Multi-connection coordination

Different types of mobile communication schemes have different characteristics and coverage. In the
migration phase to the 3G and LTE, network deployment is not always fully consistent with existing network
coverage. Existing 2G (GSM) networks provide stable coverage in comparison to 3G and LTE. Therefore, it can

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