Comments on: Mobility over LTE/SAE

By: Catapult – IxCatapult | Windancer - Stairway to ...Heaven?

Catapult – IxCatapult | Windancer - Stairway to ...Heaven? — Tue, 01 Jun 2010 15:09:02 +0000

[...] unui dispozitiv SGW/PGW real, chiar si in conditii de handover – care, dupa cum povesteam in alt post, nu sunt chiar putine si nici [...]

By: X2-based handovers | Windancer - Stairway to ...Heaven?

X2-based handovers | Windancer - Stairway to ...Heaven? — Fri, 19 Mar 2010 14:47:43 +0000

[...] I was saying in a previous post, one of the handover types that can take place over LTE/SAE is the X2-based handover. This type of [...]

By: cristina_crow

cristina_crow — Thu, 11 Mar 2010 07:08:17 +0000

@Rakesh: yes, you are right Of course, I have put there the S1-U connectivity between source SGW and target eNB, and never used it, although I had considered the case where I could use it. The Spec says that, if it exists, it is used, otherwise we should do S1-handover

By: Rakesh

Rakesh — Wed, 10 Mar 2010 21:15:06 +0000

Hey Cistina,

can you please check 2nd case:
TS 23.401, section 5.5.1.1.3 – X2-based handover with SGW relocation and NO MME relocation

I think the downlink data path is little bit messy.

It may be in three phase:
1st one which you have written which is before handover.
I think in the first phase it should be

1. PGW -(via S5/S8)> source SGW -(via S1-U)> source eNB -(via X2)> target eNB -(via LTE radio)> UE

2. PGW -(via S5/S8)> source SGW -(via S1-U)> target eNB -(via LTE radio)> UE

3. after handover:PGW -(via S5/S8)> target SGW -(via S1-U)> target eNB -(via LTE radio)> UE

Just my thinking and I may be wrong as well!

By: cristina_crow

cristina_crow — Wed, 10 Mar 2010 20:30:52 +0000

@Rakesh: hey, thanks, Rakesh. I’ve enjoyed reading about these cases. Still, all the “shiny” diagrams wouldn’t have been made without the continuous help and guidance of the guru team I am now part of

By: Rakesh

Rakesh — Wed, 10 Mar 2010 18:38:12 +0000

Very nice post! The snapshots are really guiding!
Meanwhile I haven’t reached in so depth right now, just started reading 23.401…..

It will be good to clear the doubts when I will stuck into it!

Thanks
Rakesh_