Question

Measurement configuration in LTE -

While measurement configuration is being configured by enodeB to UE in RRC connection reconfiguration message I came across a message configured like :

measObjectToAddModList {
         {
          measObjectId 1,
          measObject measObjectEUTRA : {
            carrierFreq 2250,
            allowedMeasBandwidth mbw100,
            presenceAntennaPort1 TRUE,
            neighCellConfig '00'B,
            offsetFreq dB0
           }
}

reportConfigId 2,
          reportConfig reportConfigEUTRA : {
            triggerType event : {
              eventId eventA5 : {
                a5-Threshold1 threshold-RSRP : 30,
                a5-Threshold2 threshold-RSRP : 31
               },
              hysteresis 2,
              timeToTrigger ms320
             },
            triggerQuantity rsrp,
            reportQuantity sameAsTriggerQuantity,
            maxReportCells 8,
            reportInterval ms240,
            reportAmount infinity
           }

measIdToAddModList {
         {
          measId 2,
          measObjectId 1,
          reportConfigId 2
         }
}

Now my question is - in measureobjectID there is a carrier frequency of 2250 which UE has to measure , now is this carrier frequency is of the serving cell or the neighbor if we consider that UE is reporting measID=2 because as per the A5 event which is the reportconfigID=2 UE has to report both the primary and neighbor...

Answer 1

Just have a look to measurement report format.
MeasResults ::= SEQUENCE {
measId MeasId,
measResultPCell SEQUENCE {
rsrpResult RSRP-Range,
rsrqResult RSRQ-Range
},
measResultNeighCells CHOICE {
measResultListEUTRA MeasResultListEUTRA,
measResultListUTRA MeasResultListUTRA,
measResultListGERAN MeasResultListGERAN,
measResultsCDMA2000 MeasResultsCDMA2000,
...
} OPTIONAL,
...,

For any measurement ID UE gives us report about serving cell using measResultPCell and about the neighbor cell in measResultNeighCells.

So while giving measurement object ->carrier frequency if the frequency is same so the same frequency is applicable to both serving and neighbor cell.So ue gives both serving and neighbor cell info according to the reporting triggered.

But if carrier frequency is different then then we need to specify measurement gap configuration too.while giving measurement configuration.

The frequency u will provide there it will measure for that frequency though it may same as serving cell frequency or it may be inter frequency.

correct me if i am wrong.

Comments

thanx for clearing the doubt
I have another query , it is regarding the reporting events like A1 A2 A3 etc.are there any specific events which differentiate between interfrequency and intra frequency handovers in LTE system or let me put in this way events like A1 A2 does they create handover as they donot contain any information of the neighbour.......

---

There is no specific event which will differentiate intra frequency and inter frequency as it is decided based on the carrier frequency u are giving in measurement object.

Event A1 and A2 is not used for handover as u are getting only serving cell infos like power levels but according to implementation u can first trigger A1/A2 and after that u will have an idea about serving cell strength and based on that again u can send measurement configuration by adding A3 or any other event.