Expected behavior in a mixed 4G + 5G deployment

[pahowart]

With the addition of 4G to Ellacore, what is the expected behavior of UE's in a mixed 4G 5G radio deployment?

Assuming UE's support 5G SA or NSA.

1. Do UE's move between 4G and 5G radios without dropping connection state?
2. Is NSA a supported deployment model?

Thanks for your help

[gruyaume]

Hello @pahowart ,

Thanks for reaching out.

The UE will choose a Radio Access Type (4G or 5G), scan the RF environment, and if there's a radio, connect to it. The UE can move between 4G and 5G radios, but not seamlessly. It will re-attach on the other radio and get a fresh session. Seamless movement would require inter-RAT handover, which Ella Core does not support at the moment. Some radios support that but not all of them.

"NSA" is mostly a RAN concept (a 5G radio attached to a 4G core). In theory it should work wiht Ella Core, but we haven't explicitely validated it.

[gruyaume]

To close the loop here in case others look at this discussion, as of v1.16, Ella Core fully supports 4G<->5G interworking, allowing seamless bidirectional movement between 4G and 5G.