One basic question for LTE Intra-frequency Handover (Huawei).
The HO execution takes place right after the A3 report is received?
Yes, after A3, HO preparation should be attempted by eNodeB.
So, in short, for inter-frequency:
- A2 (start measurement)
- A1 (stop measurement)
- A3 (HO execution)
You have to take in consideration A5 also.
A2 is poor coverage, you will start measure other frequencies and A5 will take place for inter-freq.
For intra-freq network will use A3.
For intra - measurement = always … A2 = poor coverage … A3 = Execute handover
For inter - measurement = after A2… A2 = poor coverage … A5 = Execute handover
As per my understanding for A3 to happen it’s not necessary A2 will happen before.
As A3 only says nbr become better then offset , not necessary serving become poor then threshold (A2 to happen).
Isn’t A3 offset better than serving?
A2 required if A3 needed for inter Freq Ho.
For intra Freq A3 no need of A2.
Yes, but by an offset ex: serving -90, nbr -85, A2 threshold for poor coverage -115.
So in this case A2 will not happen but A3 will happen.
Is it inter Freq HO?
It’s what vendor decides mainly we are keeping A5 for inter HO and A3 for Intra.
A3 can be used for intra freq as well as inter freq handover.
In case of intra freq HO, no need to meet A2 threshold as UE already able to measure intra freq nbrs.
But in case of inter freq HO, UE should be able to measure other carrier.
For which UE should meet A2 criteria and then eNB will configure m-gap for the UE.
Yes, true.
A3 can be used for interfreq handover only if the interfreq neighbor is in the same band like serving cell but on another frequency.
Between different band it’s used as well for inter Freq HO I mean different earfcn number.
Yes A3 create issue for inter Freq HO leading to ping pong impact.
But first A2 criteria need to meet first.
This is not true. A3 can be used for any target band. We are using it from band 40 toward band 3 band 5.
Yes, exactly.
With proper threshold values set… no ping pong issue observed.
I seen we keep a3offset 15 db, so very hard to meet it.
Its operator policy.
We also do it.
Like B40 to B5 15 db.
But B40 to B3 its 3 db.