What is the difference between Qrxlevmin and Qrxlevminoffset in cell selection criteria?

Question

May I know the criteria to judge whether a certain neighbor cell is an Interference in LTE?

Like in UMTS, there is a Pilot Pollution in which the criteria is usually not more than 3 active set, has more than -85 dBm RSCP and RSCP1st-RSCp4th should be equal 5 dB.

Appreciate your help.

Answer 1

As per my understanding,

The minimum RSRP requirement for cell selection is defined as Qrxlevmin.

When the UE is camped on a visited PLMN and cell selection is triggered for a high priority PLMN, then Qrxlevminoffset is subtracted from Qrxlevmin.

The offset reduces the value of Qrxlevmin, allows cell selection criteria easier

Comments

Deserves a wall recommendation for such a nice explanation :)

Answer 2

Qrxlevmin: defines the minimum RSRP values measured by the UE in a cell to be able to get unrestricted coverage-based service in that cell.

Qrxlevminoffset: Offset of signalled Qrxlevmin taken into account in the Sexlev evaluation as a result of a periodic search for a higher priority PLMN while camped normally in a VPLMN.

Now let me put this in more simple words -
Cell Selection Criteria is Signal Strength/Quality Criteria and described as follows (36.304)

UE would not start registration even though it successfully detected a cell and even decoded MIB and SIBs unless the Srxleve > 0 and Squal > 0. So if a device does not even initiate the PRACH process even when it successfully decoded all the MIB and SIBs, checking on this criteria would be a good first step for the troubleshooting. (Of course, this is not the only issues for this case. there may be USIM issue and Band Indicator Issue, PLMN issues etc).

Credit: http://www.sharetechnote.com/html/Handbook_LTE_Cell_Selection_Criterion.html