This document summarizes LTE mobile measurement events and timers used for reporting. It describes the primary and secondary cell definitions and lists the common measurement events A1-A6 and B1-B2. It also outlines various UE timers used for connection establishment, reestablishment, measurement reporting and cell reselection.

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LTELTELTELTE MobileMobileMobileMobile MeasurementsMeasurementsMeasurementsMeasurements inininin AirAirAirAir
By Justin MA Created: July 2014 Updated: 2014_0710
Date and Version Author Change Note
2014_0710; v1.0 Justin MA Mobile Measurements
Ref:

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LTELTELTELTE measurementmeasurementmeasurementmeasurement reportreportreportreport triggeringtriggeringtriggeringtriggering
PrimaryPrimaryPrimaryPrimary CellCellCellCell: The cell, operating on the primary frequency, in which the UE either performs the
initial connection establishment procedure or initiates the connection re-establishment procedure,
or the cell indicated as the primary cell in the handover procedure.
SecondarySecondarySecondarySecondary CellCellCellCell: A cell, operating on a secondary frequency, which may be configured once an
RRC connection is established and which may be used to provide additional radio resources.
EventEventEventEvent DescriptionDescriptionDescriptionDescription
A1 Serving becomes better than threshold
A2 Serving becomes worse than threshold
A3 Neighbour becomes offset better than PCell
A4 Neighbour becomes better than threshold
A5 PCell becomes worse than threshold1 and neighbour becomes
better than threshold2
A6 Neighbour becomes offset better than SCell
B1 Inter RAT neighbour becomes better than threshold
B2 PCell becomes worse than threshold1 and inter RAT neighbour
becomes better than threshold2
Ref:
3GPP TS 36.331 V12.2.0

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EventEventEventEventA1A1A1A1 (Serving(Serving(Serving(Serving becomesbecomesbecomesbecomes betterbetterbetterbetter thanthanthanthan threshold)threshold)threshold)threshold)
Ref:
http://niviuk.free.fr
/i

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Ref:
http://www.leliwa.com/en/

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EventEventEventEventA2A2A2A2 (Serving(Serving(Serving(Serving becomesbecomesbecomesbecomes worseworseworseworse thanthanthanthan threshold)threshold)threshold)threshold)
Ref:
http://niviuk.free.fr
/i

7. 7/19
Ref:
http://www.leliwa.com/en/

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EventEventEventEventA3A3A3A3 (Neighbour(Neighbour(Neighbour(Neighbour becomesbecomesbecomesbecomes offsetoffsetoffsetoffset betterbetterbetterbetter thanthanthanthan PCell)PCell)PCell)PCell)
Ref:
http://niviuk.free.fr
/i

9. 9/19
Ref:
http://www.leliwa.com/en/

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EventEventEventEventA4A4A4A4 (Neighbour(Neighbour(Neighbour(Neighbour becomesbecomesbecomesbecomes betterbetterbetterbetter thanthanthanthan threshold)threshold)threshold)threshold)
Ref:
http://niviuk.free.fr
/i

11. 11/19
Ref:
http://www.leliwa.com/en/

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EventEventEventEventA5A5A5A5
(PCell(PCell(PCell(PCell becomesbecomesbecomesbecomes worseworseworseworse thanthanthanthan threshold1threshold1threshold1threshold1 andandandand neighbourneighbourneighbourneighbour
becomesbecomesbecomesbecomes betterbetterbetterbetter thanthanthanthan threshold2)threshold2)threshold2)threshold2)
Ref:
http://niviuk.free.fr
/i
Threshold 2

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Ref:
http://www.leliwa.com/en/

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EventEventEventEventA6A6A6A6 (Neighbour(Neighbour(Neighbour(Neighbour becomesbecomesbecomesbecomes offsetoffsetoffsetoffset betterbetterbetterbetter thanthanthanthan SCell)SCell)SCell)SCell)
Ref:
http://raghudevareddy-lte-a.blogspot.tw/

15. 15/19
Ref:
http://www.leliwa.com/en/

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Ref:
http://www.leliwa.com/en/

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UE Timers
TimerTimerTimerTimer StartStartStartStart StopStopStopStop AtAtAtAt expiryexpiryexpiryexpiry
T300 Transmission of
RRCConnectionRequest
Reception of
RRCConnectionSetup or
RRCConnectionReject
message, cell re-selection and
upon abortion of connection
establishment by upper layers
Perform the actions as specified
in 5.3.3.6
T301 Transmission of
RRCConnectionReestabil
shmentRequest
Reception of
RRCConnectionReestablishmen
t or
RRCConnectionReestablishmen
tReject message as well as
when the selected cell becomes
unsuitable
Go to RRC_IDLE
T302 Reception of
RRCConnectionReject
while performing RRC
connection establishment
Upon entering
RRC_CONNECTED and upon
cell re-selection
Inform upper layers about
barring alleviation as specified in
5.3.3.7
T303 Access barred while
performing RRC
connection establishment
for mobile originating
calls
Upon entering
RRC_CONNECTED and upon
cell re-selection
Inform upper layers about
barring alleviation as specified in
5.3.3.7
T304 Reception of
RRCConnectionReconfig
uration message
including the
MobilityControl Info or
reception of
MobilityFromEUTRACom
mand message including
CellChangeOrder
Criterion for successful
completion of handover within E-
UTRA, handover to E-UTRA or
cell change order is met (the
criterion is specified in the target
RAT in case of inter-RAT)
In case of cell change order
from E-UTRA or intra E-UTRA
handover, initiate the RRC
connection re-establishment
procedure; In case of handover
to E-UTRA, perform the actions
defined in the specifications
applicable for the source RAT.
T305 Access barred while
performing RRC
connection establishment
for mobile originating
signalling
Upon entering
RRC_CONNECTED and upon
cell re-selection
Inform upper layers about
barring alleviation as specified in
5.3.3.7

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TimerTimerTimerTimer StartStartStartStart StopStopStopStop AtAtAtAt expiryexpiryexpiryexpiry
T306 Access barred while
performing RRC
connection establishment
for mobile originating CS
fallback.
Upon entering
RRC_CONNECTED and upon
cell re-selection
Inform upper layers about
barring alleviation as specified in
5.3.3.7
T310 Upon detecting physical
layer problems i.e. upon
receiving N310
consecutive out-of-sync
indications from lower
layers
Upon receiving N311
consecutive in-sync indications
from lower layers, upon
triggering the handover
procedure and upon initiating
the connection re-establishment
procedure
If security is not activated: go to
RRC_IDLE else: initiate the
connection re-establishment
procedure
T311 Upon initiating the RRC
connection re-
establishment procedure
Selection of a suitable E-UTRA
cell or a cell using another RAT.
Enter RRC_IDLE
T312 Upon triggering a
measurement report for a
measurement identity for
which T312 has been
configured, while T310
is running
Upon receiving N311
consecutive in-sync indications
from lower layers, upon
triggering the handover
procedure, upon initiating the
connection re-establishment
procedure, and upon the expiry
of T310
If security is not activated: go to
RRC_IDLE else: initiate the
connection re-establishment
procedure
T320 Upon receiving t320 or
upon cell (re)selection to
E-UTRA from another
RAT with validity time
configured for dedicated
priorities (in which case
the remaining validity
time is applied).
Upon entering
RRC_CONNECTED, when
PLMN selection is performed on
request by NAS, or upon cell
(re)selection to another RAT (in
which case the timer is carried
on to the other RAT).
Discard the cell reselection
priority information provided by
dedicated signalling.
T321 Upon receiving
measConfig including a
reportConfig with the
purpose set to reportCGI
Upon acquiring the information
needed to set all fields of
cellGlobalId for the requested
cell, upon receiving measConfig
that includes removal of the
reportConfig with the purpose
set to reportCGI
Initiate the measurement
reporting procedure, stop
performing the related
measurements and remove the
corresponding measId
T325 Timer (re)started upon
receiving
RRCConnectionReject
message with
deprioritisationTimer.
Stop deprioritisation of all
frequencies or E-UTRA signalled
by RRCConnectionReject.

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TimerTimerTimerTimer StartStartStartStart StopStopStopStop AtAtAtAt expiryexpiryexpiryexpiry
T330 Upon receiving
LoggedMeasurementCon
figuration message
Upon log volume exceeding the
suitable UE memory, upon
initiating the release of
LoggedMeasurementConfigurati
on procedure
Perform the actions specified in
5.6.6.4
T340 Upon transmitting
UEAssistanceInformation
message with
powerPrefIndication set
to normal
Upon initiating the connection
re-establishment procedure
No action.
Ref:
3GPP TS 36.331 V12.2.0