The co-existence of 4G with 5G has major implications for both user data management and SIM card interworking

The commercial s deployment of 5G will see some major changes in subscriber data management. Oliver Korfmacher, of Swedish company Enea, a provider of network functions software to the world's Tier 1 CSPs, says the change from 4G to 5G is profound in terms not only of protocols and interfaces but also, and more importantly because 5G explicitly requires a split between data and network functions.

This means a universal subscriber data repository is needed to keep all subscriber information at the back end. With 5G there are many apps that use subscriber data but, unlike the earlier generation of mobile telephony, they will no longer store it themselves. Korfmacher adds that the most important aspect here is the user data management system working in tandem with policy control system that control the authentication of all processes using the same single set of data in the back end.

5G also has many implications for user data standards. The 3GPP/GSMA have specified and interface that permits essentially seamless interworking between the HSS 4G subscriber data repository and the UDM which is the equivalent in the 5G network. The GSMA has specified a service-based interface that connects the UDM and HSS and this is being standardised now.

The reality for the forseeable future is that 4G and 5G will co-exist. Active legacy 4G networks will run alongside 5G and the ability and capability to move from and between one network technology and another will be vital for years to come. It is also problematical for the operators because of the implications for interworking between 64G and 5G and the and movement from cell to cell.

That problem can be solved by having a singled control subscriber database with both 4G and 5G front-ends using it. This is the easiest and most robust approach because it obviates double-provisioning and ensures there are no consistency problems between the two networks.

SIM card interworking and standardisation is equally important because it is not swap all 3G and 4G SIM cards for 5G SIM cards would be both a logistical m nightmare and prohibitively expensive. That said, the ability for a 5G network to authenticate and attach a subscriber to itself is extremely important.