And while I’m already writing about recent personal roaming firsts, I should also mention that I saw my first personal 5G use while roaming in Austria in May 2021.
From a technical point of view, 5G Non-Standalone roaming is quite simple if the home- and visited network have a 5G Non-Standalone radio network, and the subscriber is provisioned for 5G access in the home network. To make use of 5G abroad, the roaming device must of course enable its 5G hard- and software in the visited network, and indicate support to the network. Also, it needs to support the frequency bands used for 5G in the visited country. That’s typically not a technical problem for devices bought and used in Europe, as the same bands are used for 5G in all countries.
And finally, home- and visited network need to let the 5G subscription indication traverse the roaming interface between the Home Subscriber Server (HSS) in the home country and the Mobility Management Entity (MME) in the visited network. When both LTE core networks have been upgraded to support a 5G Non-Standalone RAN setup, that’s not much of a problem either. And that’s pretty much it then, as there are no changes required for the user plane tunnel between home and visited network.
Some might wonder why I’m excited about this!? After all, in most places, LTE networks still offer ample capacity and speeds. That is true, but I have noticed in the past that in big cities in some countries which cheap mobile tariffs, even well built LTE networks were quite loaded, especially in the evening hours. So having access to the capacity provided by a 100 MHz channel in band n78 as a roamer is certainly worth something!