1 Introduction
The network may configure an RRC_CONNECTED state UE to perform measurements and report them in accordance with the measurement configuration. The measurement configuration is provided by means of dedicated signalling i.e. using the RRCReconfiguration or RRCResume message.
For EN-DC, LTE RRCConnectionReconfiguration carries the required information to help the UE measure NR cell while being served by an LTE cell.
Measurement concept is thoroughly discussed in 38.331 section 5.5. Measurement configuration baseline in NR is similar to that of LTE.
Measurements to be performed by an UE in RRC_CONNECTED are classified in at least three measurement types:
– Intra-frequency NR measurements.
– Inter-frequency NR measurements.
– Inter-RAT measurements of E-UTRA frequencies. As of release-15, 3GPP has not specified inter-RAT measurements for 3G and 2G.
The parameters of the measurement configuration are summarized below:
1. Measurement objects: For each measurement type discussed above, one or several measurement objects can be defined. See section 3.
– In NR, each measurement object indicates frequency/time location as well as subcarrier spacing of the reference signals to be measured.
– For inter-RAT E-UTRA measurements a measurement object is a single E-UTRA carrier frequency.
2. Reporting configurations: A reporting configuration defines the reporting criteria. The reporting criteria are classified as event triggered reporting, periodic reporting, CGI reporting or SFTD reporting. See section 4.
3. Measurement identities: A list of measurement identities where each measurement identity links one measurement object with one reporting configuration. By configuring multiple measurement identities, it is possible to link more than one measurement object to the same reporting configuration, as well as to link more than one reporting configuration to the same measurement object. See section 5.
4. Quantity configurations: The quantity configuration defines the measurement filtering configuration used for measurement event evaluation and related reporting, and for periodical reporting of that measurement. See section 6.
5. Measurement gaps: Periods that the UE may use to perform measurements. Measurement gaps are discussed in the post 5G NR: Measurement GAPs.
A UE in RRC_CONNECTED state;
– Maintains a measurement object list, a reporting configuration list, and a measurement identities list.
– The measurement object list possibly includes NR and inter-RAT measurement object(s).
– Similarly, the reporting configuration list includes NR and inter-RAT reporting configurations.
– Any measurement object can be linked to any reporting configuration of the same RAT type.
– Some reporting configurations may not be linked to a measurement object. Likewise, some measurement objects may not be linked to a reporting configuration.
2 RRC Measurement Configuration
The IE MeasConfig specifies measurements to be performed by the UE, and covers intra-frequency, inter-frequency and inter-RAT mobility as well as configuration of measurement gaps. This IE is part of RRCReconfiguration or RRCResume message. MeasConfig IE contents are shown below and are discussed individually in subsequent sections.
| MeasConfig | |
| measObjectToRemoveList | SEQUENCE (SIZE (1..64)) OF MeasObjectId |
| measObjectToAddModList | SEQUENCE (SIZE (1..64)) OF MeasObjectToAddMod |
| reportConfigToRemoveList | SEQUENCE (SIZE (1..64)) OF ReportConfigId |
| reportConfigToAddModList | SEQUENCE (SIZE (1..64)) OF ReportConfigToAddMod |
| measIdToRemoveList | SEQUENCE (SIZE (1..64)) OF MeasId |
| measIdToAddModList | SEQUENCE (SIZE (1..64)) OF MeasIdToAddMod |
| s-MeasureConfig | |
| ssb-RSRP | INTEGER (0..127) |
| csi-RSRP | INTEGER (0..127) |
| quantityConfig | QuantityConfig |
| measGapConfig | MeasGapConfig |
| measGapSharingConfig | MeasGapSharingConfig |
After receiving the measurement configuration, the UE shall act in (exactly) the following order. It all depends upon what is included in the measConfig IE:
– In the first step, the UE checks to see if any measurement objects are to be removed. Now, the measObject addition/modification procedure is performed.
– In the next step, the UE first checks to see if any report configurations to be removed. Then, proceed to measurement configuration addition/modification procedure.
– The UE now performs quantity configuration procedure as per quantityConfig.
– Now, the UE first checks to see if any measurement IDs to be removed before proceeding to measurement ID addition/modification.
– Finally, measurement gap and s-measure configuration procedures are performed.
3 Measurement objects
For each measurement type (intra-, inter-frequency, or inter-RAT), one or several measurement objects can be defined.
In NR, measurement objects (MeasObjectNR) are defined for both intra- and inter-frequency. Each measurement object indicates frequency/time location as well as subcarrier spacing of the reference signals to be measured.
– The field ReferenceSignalConfig within each measObjectNR can configure the measurements for SSB, CSI-RS or both. The field rsType within reportConfigNR specifies which measurement resource type to use.
For inter-RAT E-UTRA measurements a measurement object (MeasObjecEUTRA) is a single E-UTRA carrier frequency.
Associated with each measurement object, the network may configure the following;
– A list of cell specific offsets, 'blacklisted' cells and 'whitelisted' cells.
– Blacklisted cells are not applicable in event evaluation or MR.
– Whitelisted cells are the only ones applicable in event evaluation or MR.
The IE MeasObjectToAddMod consists of an ID and an associated measObject configuration. The measObject can be either for NR or for E-UTRA.
3.1 Measurement object for NR
The IE MeasObjectNR provides information applicable for SSB based and/or CSI-RS based intra/inter-frequency measurements.
The following table presents the configuration provided by MeasObjectNR.
| MeasObjectNR | |
| ssbFrequency | ARFCN-ValueNR - INTEGER (0..3279165) |
| ssbSubcarrierSpacing | ENUMERATED {kHz15, kHz30, kHz60, kHz120, kHz240} |
| smtc1 | SSB-MTC |
| smtc2 | SSB-MTC2 |
| refFreqCSI-RS | ARFCN-ValueNR - INTEGER (0..3279165) |
| referenceSignalConfig | Reference signal configuration for SSB and CSI-RS |
| absThreshSS-BlocksConsolidation | ThresholdNR - INTEGER (0..127) |
| absThreshCSI-RS-Consolidation | ThresholdNR - INTEGER (0..127) |
| nrofSS-BlocksToAverage | INTEGER (2..16) |
| nrofCSI-RS-ResourcesToAverage | INTEGER (2..16) |
| quantityConfigIndex | INTEGER (1..2) |
| offsetMO | SSB and CSI-RS offset values (RSRP, RSRQ and SNR) |
| cellsToRemoveList | A list of PCIs (PCI-List) |
| cellsToAddModList | List of cells to add/modify -> PCI and Cell-individual offsets |
| blackCellsToRemoveList | A list of PCI ranges (PCI-RangeIndexList) |
| blackCellsToAddModList | List of cells to add/modify in the black list of cells |
| whiteCellsToRemoveList | A list of PCI ranges (PCI-RangeIndexList) |
| whiteCellsToAddModList | List of cells to add/modify in the white list of cells |
| freqBandIndicatorNR | INTEGER (1..1024) |
| measCycleSCell | ENUMERATED {sf160, sf256, sf320, sf512, sf640, sf1024, sf1280} |
Some of the important fields within MeasObjectNR are discussed below.
– ssbFrequency Indicates the frequency of the SS associated to this MeasObjectNR. This basically is an ARFCN value of a downlink NR global frequency raster.
– ssbSubcarrierSpacing Subcarrier spacing of the SSB. Only the values 15 kHz or 30 kHz (FR1), and 120 kHz or 240 kHz (FR2) are applicable.
– smtc1 and smtc2 provides primary and secondary measurement timing configurations respectively. periodicity in smtc2 can only be shorter than the periodicity indicated by periodicityAndOffset in smtc1.
– refFreqCSI-RS ‘Point A’ which is used for mapping of CSI-RS to physical resources.
– referenceSignalConfig RS configuration for SSB and CSI-RS.
– absThreshCSI-RS-Consolidation and absThreshSS-BlocksConsolidation Absolute threshold for the consolidation of measurement results per CSI-RS resource(s) and per SSB(s) respectively from L1 filter(s). These fields are used for the derivation of cell measurement results as well as for the reporting of beam measurement information per CSI-RS resource and per SSB index respectively.
– nrofSS-BlocksToAverage and nrofCSI-RS-ResourcesToAverage respectively indicates the maximum number of measurement results per beam based on SSB and CSI-RS resources to be averaged.
– quantityConfigIndex indicates the index of quantityConfigNR-List provided in MeasConfig. As of release 15, maximum number of quantityConfig is set 2, which means that this field indicates one out of two config indexes from the list.
– freqBandIndicatorNR indicates the frequency band in which the SSB and/or CSI-RS indicated in this MeasObjectNR are located.
– measCycleSCell indicates the SCell measurement periodicity when the corresponding SCell is in deactivated state.
3.2 Measurement object for E-UTRA
The IE MeasObjectEUTRA specifies information applicable for E-UTRA cells. The following table presents the configuration provided by MeasObjectEUTRA. This is typical measurement object configuration of LTE.
| MeasObjectEUTRA | |
| carrierFreq | EARFCN - INTEGER (0..262143) |
| allowedMeasBandwidth | ENUMERATED {mbw6, mbw15, mbw25, mbw50, mbw75, mbw100} |
| cellsToRemoveListEUTRAN | SEQUENCE (SIZE (1..32)) OF EUTRA-CellIndex |
| cellsToAddModListEUTRAN | SEQUENCE (SIZE (1..32)) OF EUTRA-Cell |
| blackCellsToRemoveListEUTRAN | SEQUENCE (SIZE (1..32)) OF EUTRA-CellIndex |
| blackCellsToAddModListEUTRAN | SEQUENCE (SIZE (1..32)) OF EUTRA-BlackCell |
| eutra-PresenceAntennaPort1 | When set to true, at least two cell-specific antenna ports are used in all neighbouring cells |
| eutra-Q-OffsetRange | EUTRA-Q-OffsetRange |
| widebandRSRQ-Meas | If set to true, the UE shall use wider BW for RSRQ measurements |
4 Reporting configurations
For each measurement object (discussed in section 3), one or several reporting configurations can be defined. There can be one or multiple reporting configurations per measurement object. Each reporting configuration consists of the following:
– Reporting criterion: The criterion that triggers the UE to send an MR. This can either be periodical or a single event triggered.
– RS type: The RS that the UE uses for beam and cell measurement results (SSB or CSI-RS).
– Reporting format: The quantities per cell and per beam that the UE includes in the MR (e.g. RSRP) and other associated information such as the maximum number of cells and the maximum number beams per cell to report.
There are two types of reporting configurations; One for NR measurements and the other is for inter-RAT measurements. These are discussed in subsequent sections.
The IE ReportConfigToAddModList concerns a list of reporting configurations to add or modify. Each item (ReportConfigToAddMod) in the list is a reporting configuration to be added or modified.
ReportConfigToAddMod consists of an ID and an associated reportConfig. The reportConfig can be either for NR or for inter-RAT.
4.1 Reporting Configuration - NR
The IE ReportConfigNR specifies criteria for triggering of an NR measurement reporting event. The following table presents the configuration provided by ReportConfigNR.
| ReportConfigNR | |
| reportType | |
| periodical | PeriodicalReportConfig |
| eventTriggered | EventTriggerConfig |
| reportCGI | ReportCGI |
| reportSFTD | ReportSFTD-NR |
The reporting type can be of event triggered reporting, periodic reporting, CGI reporting or SFTD reporting.
4.1.1 Event Triggered Measurement Reporting - NR
Measurement reporting (MR) events are based on cell measurement results, which can either be derived based on SSB or CSI-RS. NR Measurement reporting events are summarized in the below table.
Event
|
Description
|
Event A1
| Serving becomes better than absolute threshold |
Event A2
| Serving becomes worse than absolute threshold |
Event A3
| Neighbour becomes amount of offset better than PCell/PSCell |
Event A4
| Neighbour becomes better than absolute threshold |
Event A5
| PCell/PSCell becomes worse than absolute threshold1 AND Neighbour/SCell becomes better than another absolute threshold2 |
Event A6
| Neighbour becomes amount of offset better than SCell |
The event triggered reporting configuration could specify the following;
– Measurement reporting event (A1, A2, … A6).
– MR triggering quantity (RSRP, RSRQ or SINR) and the corresponding threshold or offset values, hysteresis, time to trigger etc…
– Reference signal type to be used for MR triggering (SSB or CSI-RS)
– Cell level measurement quantities (RSRP and/or RSRQ and/or SINR) to be included in the MR and the maximum number of cells to be reported in the MR.
– Once MR is triggered, the number of reports to be sent and interval between two reports.
– Flag indicating whether or not beam level measurements to be included in the MR.
The RRC configuration for event triggered reporting is shown below;
| EventTriggerConfig | |
| eventId | |
| eventAN | This structure is applicable for A1, A2, A3, A4, A5 and A6 |
| Threshold | RSRP, RSRQ or SINR threshold (only for A1, A2, A4, and A5) |
| Threshold2 | RSRP, RSRQ or SINR threshold (only for A5) |
| Offset | RSRP, RSRQ or SINR offset (only for A3 and A6) |
| reportOnLeave | BOOLEAN (only for A3, A4, A5, and A6) |
| hysteresis | INTEGER (0..30) |
| timeToTrigger | 0, 40, 64, 80, … 5120 msec |
| useWhiteCellList | BOOLEAN |
| rsType | ENUMERATED {ssb, csi-rs} |
| reportInterval | 120msec, 240msec, … 12min, 30min |
| reportAmount | ENUMERATED {r1, r2, r4, r8, r16, r32, r64, infinity} |
| reportQuantityCell | Combination of RSRP, RSRQ or SINR quantities |
| maxReportCells | INTEGER (1..8) |
| reportQuantityRS-Indexes | Combination of RSRP, RSRQ or SINR quantities |
| maxNrofRS-IndexesToReport | INTEGER (1..32) |
| includeBeamMeasurements | BOOLEAN |
| reportAddNeighMeas | ENUMERATED {setup} |
– eventId Indicates one of the events A1, A2, … A6 and event specific configuration;
– Threshold (1 or 2) Threshold1 is applicable for absolute threshold-based measurements events (A1, A2, A4, and A5) and Threshold2 is applicable for event A5 only. These threshold values are associated to the selected trigger quantity (e.g. RSRP, RSRQ, or SINR) per RS Type (SSB or CSI-RS) to be used in NR measurement report triggering condition.
· For RSRP, the actual value is (IE value – 156) dBm, except for the IE value 127, in which case the actual value is infinity.
· For RSRQ, the actual value is (IE value – 87)/2 dB.
· For SINR, the actual value is (IE value – 46)/2 dB.
– Offset Offset value(s) to be used in NR measurement report triggering condition for event A3 or A6. The actual value is field value * 0.5 dB
– reportOnLeave indicates whether or not the UE shall initiate the MR procedure when the leaving condition is met for a cell in cellsTriggeredList.
– hysteresis is used within the entry and leave condition of an event triggered reporting condition. The actual value is field value * 0.5 dB.
– timeToTrigger Time during which specific criteria for the event needs to be met in order to trigger an MR.
– useWhiteCellList Indicates whether only the cells included in the white-list of the associated measObject are applicable.
– rsType Type of the configured MR and it can either be SSB or CSI-RS.
– reportInterval Indicates the interval between periodical reports. When reportAmount exceeds 1, it indicates periodical event triggered reporting.
– reportQuantityCell The cell measurement quantities to be included in the MR. Either one or all of the quantities (RSRP, RSRQ, SINR) can be configured to be included.
– reportQuantityRS-Indexes Indicates which measurement information per RS index the UE shall include in the MR.
– maxNrofRS-IndexesToReport max number of RS indexes to include in the MR.
– includeBeamMeasurements When set to true, the UE shall include SSB/CSI-RS based measurement results for the quantities in reportQuantityRS-Indexes set to true for each SSB/CSI-RS index.
– reportAddNeighMeas Indicates that the UE shall include the best neighbour cells per serving frequency.
4.1.2 Periodical Measurement Reporting - NR
The contents of periodical reporting configuration are almost similar to that of event triggered (section 4.1.1) reporting configuration except that there is no event specific configuration.
The RRC configuration for periodical reporting is shown below;
| PeriodicalReportConfig | |
| rsType | ENUMERATED {ssb, csi-rs} |
| reportInterval | 120msec, 240msec, … 12min, 30min |
| reportAmount | ENUMERATED {r1, r2, r4, r8, r16, r32, r64, infinity} |
| reportQuantityCell | RSRP, RSRQ or SINR |
| maxReportCells | INTEGER (1..8) |
| reportQuantityRS-Indexes | RSRP, RSRQ or SINR |
| maxNrofRS-IndexesToReport | INTEGER (1..32) |
| includeBeamMeasurements | BOOLEAN |
| useWhiteCellList | BOOLEAN |
– rsType Type of the configured MR and it can either be SSB or CSI-RS.
– reportInterval Indicates the interval between periodical reports.
– reportQuantityCell The cell measurement quantities to be included in the MR. Either one or all of the quantities (RSRP, RSRQ, SINR) can be configured to be included.
– reportQuantityRS-Indexes Indicates which measurement information per RS index the UE shall include in the MR.
– maxNrofRS-IndexesToReport max number of RS indexes to include in the MR.
– includeBeamMeasurements When set to true, the UE shall include SSB/CSI-RS based measurement results for the quantities in reportQuantityRS-Indexes set to true for each SSB/CSI-RS index.
– useWhiteCellList Indicates whether only the cells included in the white-list of the associated measObject are applicable.
4.1.3 CGI Reporting - NR
For the purpose of ANR (Automatic Neighbour Relations), the network may configure the UE to decode and report Cell Global Identity (CGI) for a set of cells.
As shown below, the field cellForWhichToReportCGI informs the UE about the Physical Cell Identity (PCI) for which CGI to be reported.
| ReportCGI | |
| cellForWhichToReportCGI | INTEGER (0..1007) |
4.1.4 SFTD Reporting - NR
In some cases, the serving cell may not be aware of the target cells’ SSB timing information and the serving and target cells may not be time synchronized. In such cases, SFN and Frame Timing Difference (SFTD) measurements from the UE would help the network to derive the time difference of SFN and frame boundary between serving and target cell. SFTD measurements are particularly useful for EN-DC and NE-DC scenarios.
The IE ReportSFTD-NR carries configuration for SFTD reporting for NR and E-UTRA part is carried by ReportSFTD-EUTRA (section 4.2.4).
| ReportSFTD-NR | |
| reportSFTD-Meas | BOOLEAN |
| reportRSRP | BOOLEAN |
| reportSFTD-NeighMeas | ENUMERATED {true} |
| drx-SFTD-NeighMeas | ENUMERATED {true} |
| cellsForWhichToReportSFTD | SEQUENCE (SIZE (1..3)) OF PhysCellId |
– reportSFTD-Meas Indicates whether UE is required to perform SFTD measurement between PCell and NR PSCell in NR-DC.
– reportRSRP Indicates whether UE is required to include RSRP result of NR PSCell in SFTD measurement result, derived based on SSB.
– reportSFTD-NeighMeas Indicates whether UE is required to perform SFTD measurement between PCell and NR neighbour cells in NR standalone.
– drx-SFTD-NeighMeas Indicates that the UE shall use available idle periods (i.e. DRX off periods) for the SFTD measurement in NR standalone.
– cellsForWhichToReportSFTD Indicates the target NR neighbour cells for SFTD measurement between PCell and NR neighbour cells.
4.2 Reporting Configuration – Inter-RAT
The IE ReportConfigInterRAT specifies criteria for triggering of an inter-RAT measurement reporting event.
The following table presents the configuration provided by ReportConfigInterRAT.
| ReportConfigInterRAT | |
| reportType | |
| periodical | PeriodicalReportConfigInterRAT |
| eventTriggered | EventTriggerConfigInterRAT |
| reportCGI | ReportCGI-EUTRA |
| reportSFTD | ReportSFTD-EUTRA |
Similar to NR reporting configuration, the reporting type can be of event triggered reporting, periodic reporting, CGI reporting or SFTD reporting. Each of these types are discussed in the subsequent sections. Note that as of release-15, E-UTRA is the only inter-RAT for NR.
4.2.1 Event Triggered Measurement Reporting – Inter-RAT
The inter-RAT measurement reporting events for E-UTRA are B1 and B2 as shown in the below table.
Event
|
Description
|
Event B1
| Neighbour becomes better than absolute threshold |
Event B2
| PCell becomes worse than absolute threshold1 AND Neighbour becomes better than another absolute threshold2 |
The event triggered reporting configuration could specify the following;
– Measurement reporting event (B1 or B2).
– MR triggering quantity for E-UTRA (RSRP, RSRQ or SINR) and the corresponding threshold, hysteresis, time to trigger etc…An additional NR threshold is defined for the purpose of B2 measurement report event triggering.
– Reference signal type to be used for MR triggering (SSB or CSI-RS)
– Measurement quantities (RSRP and/or RSRQ and/or SINR) to be included in the MR.
– Once MR is triggered, the number of reports to be sent and interval between two reports.
The RRC configuration for event triggered reporting is shown below;
| EventTriggerConfigInterRAT | |
| eventId | |
| eventBN | Events B1 or B2 |
| b2-Threshold1 | RSRP, RSRQ or SINR thresholds, only for B2 |
| bn-ThresholdEUTRA | E-UTRA RSRP, RSRQ or SINR threshold (for B1 or B2) |
| reportOnLeave | BOOLEAN |
| hysteresis | INTEGER (0..30) |
| timeToTrigger | 0, 40, 64, 80, … 5120 msec |
| rsType | ENUMERATED {ssb, csi-rs} |
| reportInterval | 120msec, 240msec, … 12min, 30min |
| reportAmount | ENUMERATED {r1, r2, r4, r8, r16, r32, r64, infinity} |
| reportQuantity | Combination of RSRP, RSRQ or SINR quantities |
| maxReportCells | INTEGER (1..8) |
4.2.2 Periodical Measurement Reporting – InterRAT
The contents of periodical reporting configuration for inter-RAT are similar to that of NR configuration (see section 4.1.2).
The RRC configuration for periodical reporting is shown below;
| PeriodicalReportConfigInterRAT | |
| reportInterval | 120msec, 240msec, … 12min, 30min |
| reportAmount | ENUMERATED {r1, r2, r4, r8, r16, r32, r64, infinity} |
| reportQuantity | RSRP, RSRQ or SINR |
| maxReportCells | INTEGER (1..8) |
4.2.3 CGI Reporting – E-UTRA
For the purpose of ANR (Automatic Neighbour Relations), the network may configure the UE to decode and report Cell Global Identity (CGI) for a set of LTE cells.
As shown below, the field cellForWhichToReportCGI informs the UE about the Physical Cell Identity (PCI) for which CGI to be reported.
| ReportCGI-EUTRA | |
| cellForWhichToReportCGI | INTEGER (0..503) |
4.2.4 SFTD Reporting – E-UTRA
The purpose of SFTD measurements are discussed in section 4.1.4. ReportSFTD-EUTRA carries SFTD reporting configuration for E-UTRA. The following table shows the contents of ReportSFTD-EUTRA.
| ReportSFTD-EUTRA | |
| reportSFTD-Meas | BOOLEAN |
| reportRSRP | BOOLEAN |
5 Measurement identities
Measurement objects and reporting criteria are discussed in sections 3 and 4 respectively. The association between a measurement object and a reporting configuration is created by a measurement identity.
A measurement identity links together one measurement object and one reporting configuration of the same RAT.
By using several measurement identities (one for each measurement object, reporting configuration pair) it is then possible to:
– Associate several reporting configurations to one measurement object.
– Associate one reporting configuration to several measurement objects.
Below example illustrates how measurement object, reporting configuration and measurement identity linked;
The measurements identity is also used when reporting results of the measurements (within measurement reports).
As shown below, the IE MeasIdToAddModList concerns a list of measurement identities to add or modify. For each entry, measId, the associated measObjectId and the associated reportConfigId are configured.
| MeasIdToAddMod | |
| measId | INTEGER (1..64) |
| measObjectId | INTEGER (1..64) |
| reportConfigId | INTEGER (1..64) |
6 Quantity configurations
Measurement quantities are considered separately for each RAT. As shown below, the IE QuantityConfig specifies the measurement quantities and layer 3 filtering coefficients for NR and inter-RAT measurements.
| QuantityConfig | |
| quantityConfigNR-List | List from 1 up to 2 QuantityConfigNR |
| quantityConfigEUTRA | FilterConfig |
| QuantityConfigNR | |
| quantityConfigCell | ssb-FilterConfig and csi-RS-FilterConfig |
| quantityConfigRS-Index | |
– quantityConfigCell: Specifies L3 filter configurations for cell measurement results for the configurable RS Types (e.g. SSB and CSI-RS) and the configurable measurement quantities (e.g. RSRP, RSRQ and SINR).
– quantityConfigRS-Index: Specifies L3 filter configurations for measurement results per RS index for the configurable RS Types (e.g. SSB and CSI-RS) and the configurable measurement quantities (e.g. RSRP, RSRQ and SINR).
7 Measurement Configuration for NR from E-UTRA (EN-DC)
For EN-DC, the master RAT (LTE) might add secondary cell (group) either blindly or based on measurements. Measurement-based NR cell addition make sure that the UE can detect, and measure NR cell and success rate of NR cell addition procedure is much better as compare to blind addition.
E-UTRA configures the inter-RAT measurements for NR as per the procedures defined in 36.331.
7.1 EN-DC: Measurement Object Configuration for NR
The IE MeasObjectNR-r15 carries almost same configuration as that of NR measurement object configuration discussed in section 3.1. This is because, for the UE, the target cell is NR cell irrespective of EN-DC or standalone NR.
7.2 EN-DC: Reporting Configuration for NR
For event-based measurement configuration, same inter-RAT events B1 and B2 are used.
Event
|
Description
|
Event B1
| Neighbour becomes better than absolute threshold |
Event B2
| PCell becomes worse than absolute threshold1 AND Neighbour becomes better than another absolute threshold2 |
Two new IEs are added to legacy ReportConfigInterRAT IE structure to provide configuration for NR events B1 and B2.
The IE structure for ReportConfigInterRAT with IEs and fields related to NR are presented below.
| ReportConfigInterRAT | |
| triggerType | Event or Periodical |
| event | |
| eventBN | Events B1 or B2 |
| b2-Threshold1 | E-UTRA RSRP, RSRQ or SINR thresholds, only for B2 |
| bn-ThresholdNR | NR RSRP, RSRQ or SINR threshold (for B1 or B2) |
| reportOnLeave | BOOLEAN |
| hysteresis | INTEGER (0..30) |
| timeToTrigger | 0, 40, 64, 80, … 5120 msec |
| periodical | |
| purpose | ENUMERATED {reportStrongestCells, reportStrongestCellsForSON, reportCGI} |
| reportQuantityCellNR | Combination of RSRP, RSRQ or SINR quantities |
| maxReportRS-Index | INTEGER (0..32) |
| reportQuantityRS-IndexNR | Combination of RSRP, RSRQ or SINR quantities |
| reportRS-IndexResultsNR | BOOLEAN |
| reportSFTD-Meas | ENUMERATED {pSCell, neighborCells} |
8 Measurement GAP configuration
Reference: 15.8 version of 3GPP TS 38.331, 36.331, 38.300
