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Measurements in LTE E-UTRANPosted on 26. Mar, 2010 by LteWorld in Blog, ARFCN, Inter-frequency, Intra-frequency, Measurement, E-UTRAN, RRC,LTE

In LTE E-UTRAN measurements to be performed by a UE for mobility are classified as below

Intra-frequency E-UTRAN measurementsInter-frequency E-UTRAN measurementsInter-RAT measurements for UTRAN and GERANInter-RAT measurements of CDMA2000 HRPD or 1xRTT frequencies

For each measurement type a measurement identity is used by E-UTRAN when configuring measurementsas well as by the UE when reporting results of the measurements. Measurement quantities and reportingevents are considered separately for each measurement type. Measurement commands are used byE-UTRAN to order the UE to start measurements, modify measurements or stop measurements. Threereporting criteria are used: event triggered reporting, periodic reporting and event triggered periodicreporting.

For measurements within E-UTRAN at least two basic UE measurement quantities shall be supported:

Reference symbol received power (RSRP)E-UTRA carrier received signal strength indicator (RSSI)

In LTE E-UTRAN measurements performed by a UE for intra/inter-frequency mobility can be controlled byeNB, using broadcast or dedicated control. In RRC_IDLE state, a UE follows the measurement parametersdefined for cell reselection specified by the E-UTRAN broadcast. In RRC_CONNECTED state, a UE followsthe measurement configurations specified by RRC directed from the eNB (e.g. as in UTRANMEASUREMENT_CONTROL).

Intra-frequency neighbour (cell) measurements are performed by the UE when the current and target celloperates on the same carrier frequency. The UE should be able to carry out such measurements withoutmeasurement gaps. See below some intra frequency scenarios without measurement gaps

Inter-frequency neighbour (cell) measurements are performed by the UE are when the neighbour celloperates on a different carrier frequency, compared to the current cell. The UE should not be assumed to beable to carry out such measurements without measurement gaps. UE may need to perform neighbour cellmeasurements during DL/UL idle periods that are provided by DRX or packet scheduling (i.e. gap assistedmeasurements). See below some inter frequency scenarios with measurement gaps

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The UE determines whether a particular cell measurement needs to be performed in atransmission/reception gap and the scheduler needs to know whether gaps are needed. Measurement gapspatterns are configured and activated by RRC.

Fo Intra-frequency neighbouring cells, there is no need to indicate neighbouring cell in the serving cellsystem information to enable the UE to search and measure a cell i.e. E-UTRAN relies on the UE to detectthe neighbouring cells. Where as for the search and measurement of inter-frequency neighbouring cells,only the carrier frequencies need to be indicated.

For a UE to search and measure neighbouring GERAN cells, the ARFCNs of the BCCH carriers need to beindicated in the serving cell system information . For a UE to search and measure neighbouring UTRANcells, the serving cell indicates a list of carrier frequencies and scrambling codes.

Source : 3GPP TS 36.300

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Measurements in LTE E-UTRAN | LteWorld http://lteworld.org/blog/measurements-lte-e-utran

2 of 2 12/8/2014 7:38 PM