At high level, it is simple to understand overall flow of Measurement Control/Measurement Report. But if you are asked to create the measurement control message on your own, then you would understand how tricky it is. so it would be very helpful to see many example that has been verified. I will keep adding more examples as I have chance.
The two examples below come from the same test setup. A WCDMA voice call runs on Band 2, and one GSM cell is the neighbour. Both examples use the same three compressed mode patterns. They differ in how the UE reports the GSM cell. The first one uses event 3c, and the second one reports periodically. Each message is shown as a decoded capture, and the text after it explains the fields marked in red.
- Example : WCDMA to GSM with Event 3c
- Example : WCDMA to GSM with Periodic RSSI measurement
- How do the two examples differ?
- Reference
Example : WCDMA to GSM with Event 3c
How does the network ask a WCDMA UE to report a GSM cell only when that cell becomes strong? This example answers it with event 3c. The call flow needs two RRC messages before the report. The Physical Channel Reconfiguration opens the gaps that the UE needs to listen to GSM. The Measurement Control then says what to measure and when to report it.
- Band = Band 2
- Radio Bearer : 384/64
- NCC = 0
- BCC = 1
- Band = P-GSM 900
- CCH ARFCN = 5
- TCH ARFCN = 10
WCDMA Cell Configuration :
GSM Cell Configuration :
|
No |
Direction |
Message |
Comment |
|
1 |
UE <-> NW |
< Registration > |
|
|
2 |
UE <-> NW |
< Idle > |
|
|
3 |
UE <-> NW |
< Establish Voice Call > |
|
|
4 |
UE <- NW |
Physical Channel Reconfiguration |
Setup Measurement GAP |
|
5 |
UE -> NW |
Physical Channel Reconfiguration Complete |
|
|
6 |
UE <- NW |
Measurement Control |
Setup Measurement Condition |
|
7 |
UE -> NW |
Measurement Report |
Measurement Result |
(4) Physical Channel Reconfiguration
: This is to configure the measurement GAP. Refer to Compressed Mode page for the details of measurement GAP
Decoded RRC message from a tester log,
DL-DCCH-Message
integrityCheckInfo
messageAuthenticationCode: 8ac1c5a1
rrc-MessageSequenceNumber: 2
message: physicalChannelReconfiguration (10)
physicalChannelReconfiguration: later-than-r3 (1)
later-than-r3
rrc-TransactionIdentifier: 0
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: r8 (0)
r8
physicalChannelReconfiguration-r8
activationTime: 172
rrc-StateIndicator: cell-DCH (0)
dl-CommonInformation
dl-dpchInfoCommon: dl-DPCH-InfoCommon (0)
dl-DPCH-InfoCommon
cfnHandling: maintain (0)
maintain
modeSpecificInfo: fdd (0)
fdd
dl-DPCH-PowerControlInfo
modeSpecificInfo: fdd (0)
fdd
dpc-Mode: singleTPC (0)
powerOffsetPilot-pdpdch: 0
spreadingFactorAndPilot: sfd128 (5)
sfd128: pb4 (0)
positionFixedOrFlexible: fixed (0)
.... ..0. tfci-Existence: False
modeSpecificInfo: fdd (0)
fdd
defaultDPCH-OffsetValue: 0
dpch-CompressedModeInfo
tgp-SequenceList: 3 items
Item 0
TGP-Sequence-r8
tgpsi: 1
tgps-Status: activate (0)
activate
tgcfn: 2
tgps-ConfigurationParams
tgmp: gsm-CarrierRSSIMeasurement (2)
tgprc: 0
tgsn: 4
tgl1: 7
tgd: 270
tgpl1: 12
rpp: mode1 (1)
itp: mode0 (0)
ul-DL-Mode: ul-and-dl (2)
ul-and-dl
ul: sf-2 (0)
dl: sf-2 (1)
dl-FrameType: dl-FrameTypeA (0)
deltaSIR1: 10
deltaSIRAfter1: 5
Item 1
TGP-Sequence-r8
tgpsi: 2
tgps-Status: activate (0)
activate
tgcfn: 4
tgps-ConfigurationParams
tgmp: gsm-initialBSICIdentification (3)
tgprc: 0
tgsn: 4
tgl1: 7
tgd: 270
tgpl1: 8
rpp: mode1 (1)
itp: mode0 (0)
ul-DL-Mode: ul-and-dl (2)
ul-and-dl
ul: sf-2 (0)
dl: sf-2 (1)
dl-FrameType: dl-FrameTypeA (0)
deltaSIR1: 10
deltaSIRAfter1: 5
nidentifyAbort: 66
Item 2
TGP-Sequence-r8
tgpsi: 3
tgps-Status: activate (0)
activate
tgcfn: 0
tgps-ConfigurationParams
tgmp: gsmBSICReconfirmation (4)
tgprc: 0
tgsn: 4
tgl1: 7
tgd: 270
tgpl1: 8
rpp: mode1 (1)
itp: mode0 (0)
ul-DL-Mode: ul-and-dl (2)
ul-and-dl
ul: sf-2 (0)
dl: sf-2 (1)
dl-FrameType: dl-FrameTypeA (0)
deltaSIR1: 10
deltaSIRAfter1: 5
treconfirmAbort: 10
tx-DiversityMode: noDiversity (0)
dl-InformationPerRL-List: 1 item
Item 0
DL-InformationPerRL-r8
modeSpecificInfo: fdd (0)
fdd
primaryCPICH-Info
primaryScramblingCode: 9
.... ..0. servingHSDSCH-RL-indicator: False
.... ...0 servingEDCH-RL-indicator: False
dl-dpchInfo: dl-DPCH-InfoPerRL (0)
dl-DPCH-InfoPerRL: fdd (0)
fdd
pCPICH-UsageForChannelEst: mayBeUsed (0)
dpch-FrameOffset: 0
dl-ChannelisationCodeList: 1 item
Item 0
DL-ChannelisationCode
sf-AndCodeNumber: sf128 (5)
sf128: 5
scramblingCodeChange: noCodeChange (1)
tpc-CombinationIndex: 0
modeSpecificInfo2: fdd (0)
fdd
HEX : C5 60 E2 D0 92 A7 82 00 00 00 C2 B0 80 80 50 E0 02 80 10 10 01 1B FC 2E 89 45 90 20 98
01 1B FC 1E 89 45 83 40 00 C0 02 37 F8 3D 12 8A 90 40 24 00 00 34 2C 00
The capture carries three transmission gap pattern sequences, one for each GSM measurement purpose. 25.331 clause 10.3.6.33 defines these purposes in the IE TGMP. The table below lists the three sequences as they appear in the capture.
tgpsi | tgmp | tgcfn | tgpl1 | Extra field |
1 | gsm-CarrierRSSIMeasurement | 2 | 12 frames | none |
2 | gsm-initialBSICIdentification | 4 | 8 frames | nidentifyAbort = 66 patterns |
3 | gsmBSICReconfirmation | 0 | 8 frames | treconfirmAbort = 10, which is 5 s |
All three sequences use the same gap. It starts at slot 4 (tgsn = 4) and lasts 7 slots (tgl1 = 7), which is about 4.7 ms. That is a little longer than one GSM TDMA frame of 4.615 ms. The value tgd = 270 means undefined, so each pattern holds only one gap. The value tgprc = 0 means infinity, so the patterns repeat until the network stops them. 25.133 lists a 7 slot gap with undefined TGD as a valid setting for RSSI measurement in Table 8.3 and for BSIC verification in Table 8.5.
Why does GSM need three purposes? RSSI measurement only needs the signal level of a carrier. BSIC identification is harder, because the UE must find and decode the BSIC without knowing the GSM timing. BSIC re-confirmation then tracks the BSIC of a cell that is already identified. 25.331 clause 14.3.2.2 uses N identify abort as the maximum number of patterns for the initial identification. Clause 14.3.2.3 uses T reconfirm abort as the maximum time for one re-confirmation. The value 10 gives 5 seconds, because this IE counts in steps of 0.5 s.
The start frames also keep the three sequences apart. The RSSI pattern repeats every 12 frames from CFN 2, so its gaps always fall on a frame number that is 2 more than a multiple of 4. The two BSIC patterns repeat every 8 frames from CFN 4 and CFN 0, so they alternate on the multiples of 4. As a result, no two gaps land in the same frame. All three patterns use the gap on both links (ul-and-dl) and halve the spreading factor there (sf-2). The Compressed Mode page explains these fields and the SIR offsets in detail.
(6) Measurement Control
Decoded RRC message from a tester log,
DL-DCCH-Message
integrityCheckInfo
messageAuthenticationCode: cb3a1f96 [bit length 32, 1100 1011 0011 1010 0001 1111 1001 0110 decimal value 3409584022]
rrc-MessageSequenceNumber: 3
message: measurementControl (8)
measurementControl: later-than-r3 (1)
later-than-r3
rrc-TransactionIdentifier: 0
criticalExtensions: later-than-r4 (1)
later-than-r4
rrc-TransactionIdentifier-MSP: 0
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: r8 (0)
r8
measurementControl-r8
measurementIdentity: 1
measurementCommand: setup (0)
setup: interRATMeasurement (2)
interRATMeasurement
interRATMeasurementObjects: interRATCellInfoList (0)
interRATCellInfoList
removedInterRATCellList: removeAllInterRATCells (0)
removeAllInterRATCells: NULL
newInterRATCellList: 1 item
Item 0
NewInterRATCell
technologySpecificInfo: gsm (0)
gsm
interRATCellIndividualOffset: 0
bsic
ncc: 0
bcc: 1
frequency-band: dcs1800BandUsed (0)
bcch-ARFCN: 5
interRATMeasQuantity
measQuantityUTRAN-QualityEstimate
filterCoefficient: fc0 (0)
modeSpecificInfo: fdd (0)
fdd
intraFreqMeasQuantity-FDD: cpich-RSCP (1)
ratSpecificInfo: gsm (0)
gsm
measurementQuantity: gsm-CarrierRSSI (0)
filterCoefficient: fc0 (0)
bsic-VerificationRequired: required (0)
interRATReportingQuantity
.... ...0 utran-EstimatedQuality: False
ratSpecificInfo: gsm (0)
gsm
.1.. .... gsm-Carrier-RSSI: True
reportCriteria: interRATReportingCriteria (0)
interRATReportingCriteria
interRATEventList: 1 item
Item 0
InterRATEvent: event3c (2)
event3c
thresholdOtherSystem: -65
hysteresis: 0
timeToTrigger: ttt0 (0)
reportingCellStatus:
withinActSetOrVirtualActSet-InterRATcells (12)
withinActSetOrVirtualActSet-InterRATcells: e2
measurementReportingMode
measurementReportTransferMode: acknowledgedModeRLC (0)
periodicalOrEventTrigger: eventTrigger (1)
HEX : E5 9D 0F CB 1A 24 C4 01 72 00 03 20 40 2E 04 80 48 AC 80 30 50
The Measurement Control sets up an inter-RAT measurement with identity 1. It first empties the inter-RAT cell list (removeAllInterRATCells) and then adds one GSM cell. The cell carries the same NCC, BCC and BCCH ARFCN as the GSM cell configuration above.
The capture sets frequency-band to dcs1800BandUsed, while the test configured a P-GSM 900 cell. This is not a conflict. 25.331 uses this indicator only to tell the UE how to interpret the BCCH ARFCN, and it matters for the ARFCNs that DCS 1800 and PCS 1900 share. ARFCN 5 is a GSM 900 channel, so the indicator has no effect on it.
The measurement quantity is GSM carrier RSSI with filter coefficient fc0, which means no layer 3 filtering. The value bsic-VerificationRequired = required tells the UE to report only GSM cells whose BSIC it has verified. This is why the gap patterns include both BSIC purposes as well as RSSI.
The reporting criteria use event 3c. 25.331 clause 14.3.1.3 defines event 3c as the estimated quality of the other system rising above a threshold. Here the threshold is -65 dBm, the hysteresis is 0 and the time to trigger is 0 ms. So the UE reports as soon as the GSM cell reaches -65 dBm. The reportingCellStatus value e2 lets the report carry up to two inter-RAT cells. The reporting mode is eventTrigger, and the report travels on acknowledged mode RLC.
(7) Measurement Report
Decoded RRC message from a tester log,
UL-DCCH-Message
integrityCheckInfo
messageAuthenticationCode: ebb1e0d9 [bit length 32, 1110 1011 1011 0001 1110 0000 1101 1001 decimal value 3954303193]
rrc-MessageSequenceNumber: 4
message: measurementReport (8)
measurementReport
measurementIdentity: 1
measuredResults: interRATMeasuredResultsList (2)
interRATMeasuredResultsList: 1 item
Item 0
InterRATMeasuredResults: gsm (0)
gsm: 1 item
Item 0
GSM-MeasuredResults
gsm-CarrierRSSI: bc [bit length 6, 2 LSB pad bits, 1011 11.. decimal value 47]
bsicReported: verifiedBSIC (0)
verifiedBSIC: 0
eventResults: interRATEventResults (2)
interRATEventResults
eventID: e3c (2)
cellToReportList: 1 item
Item 0
CellToReport
bsicReported: verifiedBSIC (0)
verifiedBSIC: 0
HEX : F5 D8 F0 6C A2 24 08 02 5E 01 40 00
The report carries an event result and a measured result. The event result names event 3c (eventID e3c) and one cell, verified BSIC 0. That value is an inter-RAT cell id, not a BSIC. 25.331 maps id 0 to the first position of the inter-RAT cell info list. Here that position holds the only GSM cell that the Measurement Control added.
The RSSI field is a 6 bit string. The decoder shows the bits 1011 11, which is RXLEV 47. 25.331 maps RXLEV to this field as defined in 45.008 clause 8.1.4. There, RXLEV n covers -111 + n to -110 + n dBm, so RXLEV 47 means -64 to -63 dBm. The value is above the -65 dBm threshold, which matches the event that the report announces.
Three gap purposes are needed for a verified GSM report : RSSI measurement, initial BSIC identification and BSIC re-confirmation each get their own pattern.A 7 slot gap lasts about 4.7 ms : and each pattern has only one gap, because TGD is undefined.Event 3c uses an absolute threshold : here -65 dBm, with no hysteresis and no time to trigger.GSM carrier RSSI is reported as RXLEV : so the value 47 means -64 to -63 dBm.verifiedBSIC 0 points at the inter-RAT cell list : it is a cell id, not the BSIC of the cell.
Example : WCDMA to GSM with Periodic RSSI measurement
What changes when the network wants a steady stream of GSM measurements instead of one alert? This example keeps the same call flow and the same gap patterns. Only the reporting criteria in the Measurement Control change. The GSM cell also moves to DCS 1800 on ARFCN 512, and this makes the band indicator matter.
- Band = Band 2
- Radio Bearer : 384/64
- NCC = 0
- BCC = 1
- Band = DCS1800
- CCH ARFCN = 512
- TCH ARFCN = 512
WCDMA Cell Configuration :
GSM Cell Configuration :
|
No |
Direction |
Message |
Comment |
|
1 |
UE <-> NW |
< Registration > |
|
|
2 |
UE <-> NW |
< Idle > |
|
|
3 |
UE <-> NW |
< Establish Voice Call > |
|
|
4 |
UE <- NW |
Physical Channel Reconfiguration |
Setup Measurement GAP |
|
5 |
UE -> NW |
Physical Channel Reconfiguration Complete |
|
|
6 |
UE <- NW |
Measurement Control |
Setup Measurement Condition |
|
7 |
UE -> NW |
Measurement Report |
Measurement Result |
(4) Physical Channel Reconfiguration
: This is to configure the measurement GAP. Refer to Compressed Mode page for the details of measurement GAP
Decoded RRC message from a tester log,
DL-DCCH-Message
integrityCheckInfo
messageAuthenticationCode: 4cb5b4d8 [bit length 32, 0100 1100 1011 0101 1011 0100 1101 1000 decimal value 1286976728]
rrc-MessageSequenceNumber: 6
message: physicalChannelReconfiguration (10)
physicalChannelReconfiguration: later-than-r3 (1)
later-than-r3
rrc-TransactionIdentifier: 0
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: r8 (0)
r8
physicalChannelReconfiguration-r8
activationTime: 32
rrc-StateIndicator: cell-DCH (0)
dl-CommonInformation
dl-dpchInfoCommon: dl-DPCH-InfoCommon (0)
dl-DPCH-InfoCommon
cfnHandling: maintain (0)
maintain
modeSpecificInfo: fdd (0)
fdd
dl-DPCH-PowerControlInfo
modeSpecificInfo: fdd (0)
fdd
dpc-Mode: singleTPC (0)
powerOffsetPilot-pdpdch: 0
spreadingFactorAndPilot: sfd128 (5)
sfd128: pb4 (0)
positionFixedOrFlexible: fixed (0)
.... ..0. tfci-Existence: False
modeSpecificInfo: fdd (0)
fdd
defaultDPCH-OffsetValue: 0
dpch-CompressedModeInfo
tgp-SequenceList: 3 items
Item 0
TGP-Sequence-r8
tgpsi: 1
tgps-Status: activate (0)
activate
tgcfn: 2
tgps-ConfigurationParams
tgmp: gsm-CarrierRSSIMeasurement (2)
tgprc: 0
tgsn: 4
tgl1: 7
tgd: 270
tgpl1: 12
rpp: mode1 (1)
itp: mode0 (0)
ul-DL-Mode: ul-and-dl (2)
ul-and-dl
ul: sf-2 (0)
dl: sf-2 (1)
dl-FrameType: dl-FrameTypeA (0)
deltaSIR1: 10
deltaSIRAfter1: 5
Item 1
TGP-Sequence-r8
tgpsi: 2
tgps-Status: activate (0)
activate
tgcfn: 4
tgps-ConfigurationParams
tgmp: gsm-initialBSICIdentification (3)
tgprc: 0
tgsn: 4
tgl1: 7
tgd: 270
tgpl1: 8
rpp: mode1 (1)
itp: mode0 (0)
ul-DL-Mode: ul-and-dl (2)
ul-and-dl
ul: sf-2 (0)
dl: sf-2 (1)
dl-FrameType: dl-FrameTypeA (0)
deltaSIR1: 10
deltaSIRAfter1: 5
nidentifyAbort: 66
Item 2
TGP-Sequence-r8
tgpsi: 3
tgps-Status: activate (0)
activate
tgcfn: 0
tgps-ConfigurationParams
tgmp: gsmBSICReconfirmation (4)
tgprc: 0
tgsn: 4
tgl1: 7
tgd: 270
tgpl1: 8
rpp: mode1 (1)
itp: mode0 (0)
ul-DL-Mode: ul-and-dl (2)
ul-and-dl
ul: sf-2 (0)
dl: sf-2 (1)
dl-FrameType: dl-FrameTypeA (0)
deltaSIR1: 10
deltaSIRAfter1: 5
treconfirmAbort: 10
tx-DiversityMode: noDiversity (0)
dl-InformationPerRL-List: 1 item
Item 0
DL-InformationPerRL-r8
modeSpecificInfo: fdd (0)
fdd
primaryCPICH-Info
primaryScramblingCode: 9
.... ..0. servingHSDSCH-RL-indicator: False
.... ...0 servingEDCH-RL-indicator: False
dl-dpchInfo: dl-DPCH-InfoPerRL (0)
dl-DPCH-InfoPerRL: fdd (0)
fdd
pCPICH-UsageForChannelEst: mayBeUsed (0)
dpch-FrameOffset: 0
dl-ChannelisationCodeList: 1 item
Item 0
DL-ChannelisationCode
sf-AndCodeNumber: sf128 (5)
sf128: 5
scramblingCodeChange: noCodeChange (1)
tpc-CombinationIndex: 0
modeSpecificInfo2: fdd (0)
fdd
HEX : A6 5A DA 6C 32 A7 82 00 00 00 C0 80 80 80 50 E0 02 80 10 10 01 1B FC 2E 89 45 90 20 98
01 1B FC 1E 89 45 83 40 00 C0 02 37 F8 3D 12 8A 90 40 24 00 00 34 2C 00
The gap patterns in this capture are the same as in the event 3c example, field by field. Only the activation time (32 instead of 172) and the integrity check fields differ. So the explanation of the three gap patterns above applies here without change.
(6) Measurement Control
Decoded RRC message from a tester log,
DL-DCCH-Message
integrityCheckInfo
messageAuthenticationCode: de130554 [bit length 32, 1101 1110 0001 0011 0000 0101 0101 0100 decimal value 3725788500]
rrc-MessageSequenceNumber: 7
message: measurementControl (8)
measurementControl: later-than-r3 (1)
later-than-r3
rrc-TransactionIdentifier: 0
criticalExtensions: later-than-r4 (1)
later-than-r4
rrc-TransactionIdentifier-MSP: 0
criticalExtensions: criticalExtensions (1)
criticalExtensions: criticalExtensions (1)
criticalExtensions: r8 (0)
r8
measurementControl-r8
measurementIdentity: 1
measurementCommand: setup (0)
setup: interRATMeasurement (2)
interRATMeasurement
interRATMeasurementObjects: interRATCellInfoList (0)
interRATCellInfoList
removedInterRATCellList: removeAllInterRATCells (0)
removeAllInterRATCells: NULL
newInterRATCellList: 1 item
Item 0
NewInterRATCell
technologySpecificInfo: gsm (0)
gsm
interRATCellIndividualOffset: 0
bsic
ncc: 0
bcc: 1
frequency-band: dcs1800BandUsed (0)
bcch-ARFCN: 512
interRATMeasQuantity
measQuantityUTRAN-QualityEstimate
filterCoefficient: fc0 (0)
modeSpecificInfo: fdd (0)
fdd
intraFreqMeasQuantity-FDD: cpich-RSCP (1)
ratSpecificInfo: gsm (0)
gsm
measurementQuantity: gsm-CarrierRSSI (0)
filterCoefficient: fc0 (0)
bsic-VerificationRequired: required (0)
interRATReportingQuantity
.... ...0 utran-EstimatedQuality: False
ratSpecificInfo: gsm (0)
gsm
.1.. .... gsm-Carrier-RSSI: True
reportCriteria: periodicalReportingCriteria (1)
periodicalReportingCriteria
periodicalReportingCriteria
reportingAmount: ra-Infinity (7)
reportingInterval: ril1 (3)
reportingCellStatus: withinActSetOrVirtualActSet-InterRATcells (12)
withinActSetOrVirtualActSet-InterRATcells: e1 (0)
measurementReportingMode
measurementReportTransferMode: acknowledgedModeRLC (0)
periodicalOrEventTrigger: periodical (0)
HEX : EF 09 82 AA 3A 24 C4 01 72 00 03 20 50 06 04 80 5F 9E 00
The cell list now holds a DCS 1800 cell on ARFCN 512. Here the band indicator does matter. ARFCN 512 lies in the range that DCS 1800 and PCS 1900 share, so dcs1800BandUsed tells the UE to read it as a DCS 1800 channel. The measurement quantity and the BSIC verification are the same as in the event 3c example.
The reporting criteria change to periodical reporting. The decoder shows periodicalReportingCriteria twice, and this is the real structure. In 25.331 the choice periodicalReportingCriteria carries the type PeriodicalWithReportingCellStatus, which holds a second field with the same name. The value ra-Infinity means the UE never stops reporting. The value ril1 sets the interval to 1000 ms, as 25.331 clause 10.3.7.53 defines it. The reportingCellStatus value e1 limits each report to one inter-RAT cell, and the reporting mode changes to periodical as well.
(7) Measurement Report
Decoded RRC message from a tester log,
UL-DCCH-Message
integrityCheckInfo
messageAuthenticationCode: f8c15c8b [bit length 32, 1111 1000 1100 0001 0101 1100 1000 1011 decimal value 4173421707]
rrc-MessageSequenceNumber: 0
message: measurementReport (8)
measurementReport
measurementIdentity: 1
measuredResults: interRATMeasuredResultsList (2)
interRATMeasuredResultsList: 1 item
Item 0
InterRATMeasuredResults: gsm (0)
gsm: 1 item
Item 0
GSM-MeasuredResults
gsm-CarrierRSSI: 98 [bit length 6, 2 LSB pad bits, 1001 10.. decimal value 38]
bsicReported: verifiedBSIC (0)
verifiedBSIC: 0
HEX : FC 60 AE 45 82 20 08 02 4C 00
A periodic report carries no event result. It only has the measured results, with one GSM cell. The RSSI bits 1001 10 give RXLEV 38, which means -73 to -72 dBm. The cell is still reported as verified BSIC 0, so the UE has verified the BSIC of this cell too. The UE sends a report like this one every second until the network releases the measurement.
The gap patterns do not depend on the reporting type : the same three sequences serve both examples.The band indicator matters for ARFCN 512 : it decides between DCS 1800 and PCS 1900.Periodic reporting needs an amount and an interval : ra-Infinity and ril1 give one report per second without end.A periodic report has no event result : only the measured results are present.
How do the two examples differ?
Building a Measurement Control by hand is easier with the two working examples side by side. The table below lists the fields that differ between them, and the fields that both of them rely on.
Field | Event 3c example | Periodic RSSI example |
GSM band and BCCH ARFCN | P-GSM 900, ARFCN 5 | DCS 1800, ARFCN 512 |
frequency-band | dcs1800BandUsed, no effect on ARFCN 5 | dcs1800BandUsed, selects DCS 1800 |
Gap patterns | RSSI, initial BSIC, BSIC re-confirmation | the same three |
reportCriteria | interRATReportingCriteria, event 3c at -65 dBm | periodicalReportingCriteria, ra-Infinity, ril1 |
reportingCellStatus | e2 | e1 |
periodicalOrEventTrigger | eventTrigger | periodical |
Reported GSM carrier RSSI | RXLEV 47, -64 to -63 dBm | RXLEV 38, -73 to -72 dBm |
eventResults | e3c with verified BSIC 0 | absent |
When a report does not arrive, three checks cover most cases. First, a UE that needs compressed mode can measure GSM only inside gaps with the matching purpose. 25.331 clause 8.6.7.6 does not require such a UE to include the GSM carrier RSSI when no RSSI pattern is active. It also does not require a verified cell id when no BSIC pattern is active. Second, the ARFCN and the band indicator must point at the carrier that the GSM cell really uses. Third, an event threshold has to sit below the level that the UE will measure, or the event never triggers.
The periodic example is a useful first step for that reason. It reports whatever the UE measures, so it shows the real RXLEV before an event threshold is chosen.
Only the reporting criteria separate the two examples : the gap patterns and the measurement quantity are the same.A missing gap purpose can empty the report : RSSI and both BSIC purposes are needed when BSIC verification is required.Check the band indicator against the ARFCN : it changes the carrier only in the range DCS 1800 and PCS 1900 share.Set an event threshold from a periodic report : the reported RXLEV shows where the GSM cell really is.
Reference
- 3GPP TS 25.331 v19.0.1 : clauses 8.6.7.6, 10.3.6.33, 10.3.7.30, 10.3.7.53, 14.3.1.3, 14.3.2.2 and 14.3.2.3, and the ASN.1 of clause 11.3
- 3GPP TS 25.133 v19.0.0 : clause 8.1.2.5, GSM measurements in CELL_DCH, and clause 9.1.4, GSM carrier RSSI
- 3GPP TS 45.008 v19.0.0 : clause 8.1.4, range of the RXLEV parameter