What are different ways for SCG addition?

Hello NSA experts.

What are different ways for SCG addition?

As of now below known:

  1. Coverage based
  2. Coverage and volume based
  3. Blind based

For point 2 and 3 do UE report b1 or b2 MR?

Please suggest if there any other way or correct, or if it’s wrong.

During SCG addition, if data ongoing at LTE leg, will it stop?
I mean, any interruption there or not?
Any view on this?

NR leg addition can be blind or measurement based.

We did not face any issue on nr leg addition while data ongoing on LTE leg in 3x run
but you can align.

Few params like meas stop after sn add & desired act notification enum in eNB side & also check gNB side ENDC config to avoid any issues.

I think volume buffer based as well there.

Can you tell for blind case how it works?

Any B1 or B2 measurement there with blind based?

In our NSA setup, it supports, however you can check eNB blind switch is ON / OFF, simulator UE capability is properly alligned, no restriction imposed on NR on EPC side.

But most of work scope is with meas based B1.

Not observed B1 that time, you can ICS message on LTE eNB for this.

For blind SCG addition, no need of B1 event.

Yes, I think same no need of B1 event for volume or blind based.

Is there a feature?

Like we have DL/UL split, is there some similar mechanism or different?

There is this feature RwR with Data fordwarding, but i works for LTE to 5G SA.

Thanks, it looks logical.

So for NSA case during SCG addition it’s like LTE Leg data will drop.

Most of the operators the SCG will be added based on the measurements of B1. After B1 measurements and UE met cretiria enb will sgnb setup request