INITIAL LTE KPI TROUBLESHOOTING METRICS - NOKIA
ACCESSIBILITY
RETAINABILITY
MOBILITY
Measure of the ability of a user
to obtain an E-RAB from the
system.
The Initial E-RAB
Establishment process can be
divided into the following
phases:
Measure of the ability of a user
to retain the E-RAB once
connected, for the desired
duration.Call drops are also
referred as Radio Link
Failures (RLF).
UE moves from one eNB to
target eNB while keeping its
connected state. LTE Services
will be uninterrupted.
Preparation – The Source
eNodeB sends a request to the
Target eNodeB, which
performs admission control
Execution – After successful
preparation, the Source
eNodeB sends a handover
command to the UE
The mechanisms dealing with
RLF are implemented at both
UE and eNB side.
1.If UE detects radio link
problems it tries to recover
from RLF during specified
interval of time by RRC
connection re-establishment
procedure.
2.If eNB detects a radio link
RRC -Possible Causes of
problem it will wait until the
degradation
recovery (cancellation of
User or Control Plane and
RLF state), or release the
MME Overload ,Timer Expiry, UE.
protocol Error,Lack of PUCCH The call drops can also be
Resources,Max no of RRC
initiated by the eNB (or MME)
Connection Reached,RF
in other scenarios such as
Quality Issues,cell availability timing alignment timer expiry,
S1 Signalling -Possible
S1 reset etc.
Causes of degradation
Transport issue,Wrongly
Retainability Issues
Configured TAC,Degraded due UE SIDEto H/W Issue
1.T310 expiry
ERAB -Possible Causes of
2.Maximum number of RLC
degradation
retransmissions
Radio & Transport resources 3.Handover failure (T304
not available,Radio connection expiry)
with UE lost,Failure radio
4.Non-HO related random
interface procedure,Mobility
access problem
1.RRC CONNECTION
ESTABLISHMENT
2.S1 SIGNALING
CONNECTION
ESTABLISHMENT
3.INITIAL E-RAB
ESTABLISHMENT OR E-RAB
ADDITION
Other Factor Impacting
Accessibility
RF Quality 1.Poor Coverage in DL and UL
impact the accessibility KPI
2.High UL RSSI can cause
degradation
3.Low SINR impact the KPI
4.Check whether the block
error rate (BLER) is
excessively high on the radio
interface.
Admission Control
Cell Availability
Baseband Pooling Admission
Failures
Failure Counters for RRC:
SIGN_CONN_ESTAB_FAIL_O
VLUP
SIGN_CONN_ESTAB_FAIL_C
P_POOL
SIGN_CONN_ESTAB_FAIL_O
VLMME
SIGN_CONN_ESTAB_FAIL_P
UCCH
SIGN_CONN_ESTAB_FAIL_M
AXRRC
LTE_5590c E-UTRAN RRC
Connection Setup Rejection
Ratio (%)
LTE_5229e RRC Connection
Setup Failure Ratio due to
"RRC timer expiry" failure (%)
LTE_5230e RRC Connection
Setup Failure Ratio per Cause
RRCCOMPL_ERROR
No. of Establishment RRC
Connections per cell
(Connected Users)
RRC connected users,max
Avg_RRC_UE_Per_Cell
eNodeB SIDE1.PUSCH RLF
2.CQI RLF
3.HARQ RLF
4.PDCCH Order failure
5.Maximum RLC
Retransmissions Exceeded at
eNB
6.GTP-U failure at eNB
7.S1 reset
Poor coverage*
Alarms*
High Load (high traffic)*
H/W issue (Re-set first) if
required replace RRU*
VSWR over threshold*
Faliure Counters:
ERAB_REL_ENB_RNL_UEL
ERAB_REL_ENB_RNL_EUG
R
ERAB_REL_ENB_TNL_TRU
ERAB_REL_ENB_RNL_RRN
A
ERAB_REL_HO_FAIL_TIM
EPC_EPS_BEARER_REL_RE
Q_RNL
EPC_EPS_BEARER_REL_RE
Q_OTH
EPS_BEARER_SETUP_COM
PLETIONS
RRC_CON_RE_ESTAB_ATT_
HO_FAIL
RRC_CON_RE_ESTAB_ATT_
HO_OTHER
Parameters tuning for Call
Drop:
rrcGuardTimer - 3sec to
12sec
INTEGRITY
User data speed in Mbps
Possible Causes of
degradation:
LTE Downlink ThroughputCell Load(Users and PRB)
PDCCH Blocking & higher
Usage
Grant Bottleneck
Air Interface
Condition(RSSI,SINR,BLER)
RTT/Retransmission
Ul thp
Mobility Issues
TM mode setting
RRC Connected Users
1-Preparation Phase
CQI Reporting Parameter
1.1- Wrong Tac Definition
Scheduler Limitation
1.2-X2-Link Failure
QOS Profile
1.3-CAC Failure
Application server
1.4-Prep Timer Expiry
eNB Data build
1.5-Missing Neighbor
1.6-MME pool should be same RS Pwr boost
Others (VSWR,Backhaul
1.7-Target cell is overloaded
Capacity)
1.8-Target cell Unavailable
Possible Causes of
1.9-Site Configuration issue
degradation:
2.0-Target cell has a fault
(alarm, disabled cell, etc.)
LTE Uplink Throughput
Cell Load(Users and PRB)
Air Interface
2-Execution Phase
Condition(RSSI,SINR,BLER)
2.1-Failure due to delay HO
RTT/Retransmission
2.2-Timer Expiry
DL thp
2.3-RLF
2.4-ANR PCI Conflict (Collision Scheduler Limitation
QOS Profile
& Confusion)*
2.5-Target exceeds cell range Application server
eNB Data build
2.6-Target is a sleeping cell
Others (VSWR,Backhaul
2.7-Target has high uplink
Capacity)
interference
Power control Strategy
2.8-Poor RF conditions
Proactive Scheduling
2.9-Due to radio deaf radio
PUCCH and PRACH
Overheads
3-Other Causes
3.1-Poor Coverage
GOOD THROUGHPUT
3.2-Interference
1.RSSI- (< -105 DBM)
3.3-Wrong Parameters in
2.SINR- Value >= 20
eNodeB
3.PRB UTILIZATION- (<80%)
4.POWER RESTRICTED
Failure Counters :
FAIL_INTRA_ENB_HO_PREP TRANSPORT BLOCK-UL - (<
50%)
_AC
FAIL_ENB_HO_PREP_OTH 5.CQI-(>10)
FAIL_ENB_HO_PREP_TIME 6.MIMO RANK 2 TM2(PDF
RANGE 1) & TM3(PDF
FAIL_ENB_HO_PREP_AC
FAIL_ENB_HO_PREP_OTHE RANGE 2)
7.HIGH USAGE OF 64 QAM
R
INTER_X2_HO_PREP_FAIL_ AND 16 QAM SCHEME IN DL
8.Rank indicator (should be 2)
QCI
INTER_S1_HO_PREP_FAIL_
Parameter to Improve PRB
TIME
INTER_S1_HO_PREP_FAIL_ inactivityTimer - 30
NORR
INTER_S1_HO_PREP_FAIL_ Parameter to Improve
PDCCH:
OTHER
INTER_S1_HO_PREP_FAIL_ actLdPdcch – 0
QCI
actOlLaPdcch – 1
enableAmcPdcch – 1
enablePcPdcch – 1
Parameter for HO
pdcchAggMsg4 – 8
Improvement:
pdcchAggPaging – 4
cellindividualoffsetEutran
pdcchAggPreamb – 4
hysteresisA3
pdcchAggRaresp – 4
timeToTriggerA3
pdcchAggSib – 4
a5ReportIntervalInterFreqpdcchAlpha – 0.8
240ms
pdcchCqiShift – (-5)
a5TimeToTriggerInterFreqpdcchHarqTargetBler – 1
480ms
offsetFreqInter-0dB
measQuantInterFreq-rsrp
interPresAntP-true
hysThreshold3InterFreq-2
threshold3InterFreq-60
threshold3aInterFreq-11
PARAMETERS INFO
aPucchMinNumRrc:
Minimum allocated number of
UEs in the cell which may
establish a RRC connection.
countdownPucchCompr
specifies the countdown timer
that defines how long it takes
before any new SIB
modification process may be
triggered again by a PUCCH
region compression.
rrcGuardTimer:
This timer is started when an
RRC message for setup,
modification or release of a
radio bearer is sent to the UE.
When the timer expires, the
corresponding procedure is
aborted
Power Parameters:
pMax- maximum output power
of the cell
dlCellPwrRed - dlCellPwrRed
value 0dB only
supported,Improve cell edge
behaviour , reduce interference
and power consumption
dlChBw-Downlink channel
bandwidth
dlRsBoost- Transmission
power of the downlink
reference signals in a cell is
boosted (positive value)
respectively deboosted
(negative value) compared to
PDSCH
tHalfRrcCon:
The minimal time period during
which the internal state and the
resources associated with an
half-open RRC connection (i.e.
one for which no RRC
connection setup complete
message has yet been
received) must not be deleted
in the eNB.
p0NomPucch:
This parameter defines the cell
specific nominal power to be
used for PUCCH power
calculation in UE uplink power
control equation (P2), for
controlling mean received SNR
for control data.
p0NomPusch:
This parameter defines the cell
specific nominal power for the
PUSCH. Used for P0_PUSCH
calculation in UE uplink power
control equation (P1) for
controlling the mean received
SNR for user data during
(re)transmission corresponding
to a received PDCCH with DCI
format 0 associated with a new
packet transmission.
Qrxlevmin:
Parameter to Improve
Specifies the minimum
Latency
required RX RSRP level in the
ilReacTimerUl – 0
cell.
cellSrPeriod – 2ms
Parameter to Improve MIMO
"RRC timer expiry" failure (%) HO_FAIL
LTE_5230e RRC Connection RRC_CON_RE_ESTAB_ATT_
Setup Failure Ratio per Cause HO_OTHER
RRCCOMPL_ERROR
No. of Establishment RRC
Connections per cell
(Connected Users)
RRC connected users,max
Avg_RRC_UE_Per_Cell
Parameters tuning for Call
Drop:
rrcGuardTimer - 3sec to
12sec
No. of Active UE’s per Cell
pdcchOrderConfig - 1 to 0
ENB_LOAD_ACT_UE_AVG
rlcProftPollRetr - 120ms to
ENB_LOAD_ACT_UE_MA
200ms
nCqiDtx - 100 or 250 to 0
Failure Counters for S1:
rlcProfmaxRetxThresh - t16 to
S1_SETUP_FAIL_IND_BY_M t32
ME
maxRetxThreshSrbUL - 16 to
S1_SETUP_FAIL_NO_RESP 32
Failure Counters for ERAB:
ERAB_INI_SETUP_FAIL_RNL
_RRNA
ERAB_INI_SETUP_FAIL_TNL
_TRU
ERAB_INI_SETUP_FAIL_RNL
_UEL
ERAB_INI_SETUP_FAIL_RNL
_RIP
LTE_5750a Cell Availability
Ratio (%)
Parameters tuning for Call
Failures:
aPucchMinNumRrc - 10 to 30
countdownPucchCompr 15min to 60min
tHalfRrcCon - 3000ms to
6000ms
p0NomPucch: -120dBm to 117dBm
p0NomPusch: -106dBm to 102dBm
Qrxlevmin: -120dBm to 114dBm
Features:
actBbPooling - true (
Baseband Pooling Feature )
RRC Connections, GBR,
Scheduled UEs/TTI are
dynamically distributed
among cells depending on
live traffic load.
Improved individual cell
capacity (up to 76% more RRC
connections possible in a
single cell).
Parameter to Improve ERAB:
rrcGuardTimer - 3sec to
12sec
dFpucchF1b - 0
dlSrbCqiOffset - -20 to -40
RLF Timer GUI Values:
T300 - 1000ms
T301 - 1500ms
T310 - 2000ms
T311 - 5000ms
t304IntraLte - 2000ms
t304InterRAT - 500ms
N310 - n20
N311 - n1
Uplink PUSCH DTX detection
and recovery
rlpDetEndNUl - 3(Mint)
rlpDetMaxNUl - 1000(Mint)
CQI DTX detection and
recovery
nCqiDtx - 0
nCqiRec - 2
Uplink Ack/Nack DTX
Detection
rlpDetEndNoDl - 3(Mint)
rlpDetMaxNoDl - 1000(Mint)
rlpDetMaxTimeDl - 0(Mint)
UE Detected Radio Link
Failure initiates RRC
Connection Reestablishment:
Possible Failure Reasons
resulting in Drop:
When the signaling shown is
not completed, the RRC reestablishment procedure fails
Sleeping Cells Detection :
The reasons for unsuccessful
Early detection” which will
RRC re-establishment can be
trigger after 30mins of below
associated to, the transmission
event :
1.RRC connection setup failure of RRC REESTABLISHMENT
REJECT message from the
rate >= 1%
eNB .
2.ERAB drop rate >=10%
“Normal detection” which will Feature not activated
Reception of another RRC
trigger after 30mins of no
activity on the cell due to below CONNECTION
REESTABLISHMENT
procedure :
REQUEST
1.RRC attempts
while the procedure is already
2.Throughput
ongoing,
3.Successful RRC / bearer
Unknown Reestab UE-Identity,
setup attempts
Loss of S1 or cell service,
4.PRBs used for DL or UL
CAC failure
transmission
a5ReportIntervalInterFreq240ms
a5TimeToTriggerInterFreq480ms
pdcchAggSib – 4
pdcchAlpha – 0.8
pdcchCqiShift – (-5)
pdcchHarqTargetBler – 1
offsetFreqInter-0dB
measQuantInterFreq-rsrp
Parameter to Improve
interPresAntP-true
Latency
hysThreshold3InterFreq-2
ilReacTimerUl – 0
threshold3InterFreq-60
cellSrPeriod – 2ms
threshold3aInterFreq-11
Parameter to Improve MIMO
a3OffsetRsrpInterFreq-15
dlMimoMode - 10
a3ReportIntervalRsrpInterFreq- mimoClCqiThD - 7
240ms
mimoClCqiThU - 8
a3TimeToTriggerRsrpInterFreq-mimoClRiThD - 1.4
320ms
mimoClRiThU - 1.6
hysA3OffsetRsrpInterFreq-15 mimoOlCqiThD - 7
threshold3InterFreqQci1-60
mimoOlCqiThU - 8
threshold3aInterFreqQci1-11 mimoOlRiThD - 1.4
thresholdRsrpIFLBFilter--44
mimoOlRiThU - 1.6
thresholdRsrpIFSBFilter--100 Parameter to Improve
thresholdRsrqIFSBFilter--10
PUSCH:
tS1RelPrepL - 2000 ms
ulpcPuschConfig
ulpcUpqualSch - 20
Handover Preparation :
ulpcPuschConfig
RRC Measurement Control
ulpcLowqualSch - 0
(Source ENB ->UE)
ulpcPuschConfig
RRC Measurement Report (UE ulpcUplevSch - -88
-> Source ENB)
ulpcPuschConfig
X2AP Handover Request
ulpcLowlevSch - -103
(Source ENB -> Target ENB) actUlpcMethod - 0
Uplink S1 Bearer
deltaTfEnabled - 0
Establishment (SGW <->
p0NomPusch - -80
Target ENB)
ulpcAlpha - 7
X2AP Handover Request
Parameter to Improve
Acknowledge (Target ENB -> PUCCH:
Source ENB)
dFpucchF1 - 1
X2 Bearer Establishment
dFpucchF1b - 0
(Source ENB <-> Target ENB) dFpucchF2 - 1
dFpucchF2a - 1
Handover Execution :
dFpucchF2b - 1
1. RRC Connection
p0NomPucch - -116
Reconfiguration Request
Parameter to Improve MCS:
(Source ENB ->UE)
actModulationSchemeUL - 0
2. X2AP SN Transfer Status
actUlLnkAdp - 5
(Source ENB -> Target ENB) harqMaxTrDl - 5
3. DL data flow during HO
iniMcsDl - 4
preparation (PGW -> UE)
iniMcsUl - 5
4. UL data flow during HO
ulsSchedMethod - 0
preparation (UE -> PGW)
Parameter to Improve RF
5. RACH Preamble (UE ->
Quality:
Target ENB)
allowPbIndexZero - 0
6. Random Access Response dlCellPwrRed - 0
(Target ENB -> UE)
dlPcfichBoost - 0
7. RRC Connection
dlPhichBoost - 0
Reconfiguration Complete (UE -pMax > Target ENB)
qrxlevmin - -130
8. Transmit transmission of
queued downlink data (Target Counters for troubleshoot:
ENB -> UE)
AVG UL PRBs
9. DL data flow during HO
AVG DL PRBs
execution (PGW -> UE)
PRB_USED_UL_TOTAL
10. UL data flow during HO
PRB_USED_PUSCH
execution (UE -> PGW)
PRB_USED_PUCCH
11. S1AP path switch Request PRB_USED_DL_TOTAL
(Target ENB -> MME)
PRB_USED_PDSCH
12. Modify Bearer Request
DL_SCH_Kbits_per_PRB_use
(MME -> PGW)
d
13. Modify Bearer Response ( UL_SCH_Kbits_per_PRB_use
PGW -> MME)
d
14. End Marker ( PGW ->
Grant BottleNeck
Target ENB)
Average AGG level used for
15. Downlink data flow after
PDCCH
handover (PGW->UE)
scheduling(LTE_1084a)(#)
16. S1AP path switch Request Average Burst Initial Scheduler
Ack (MME -> Target ENB)
Delay
17. . X2AP UE Context
PDCP_PDU_Delay_PerLstTTI
Release (Target ENB ->
_V1 (ms)
Source ENB)
RSSI_PUSCH_AVG SINR_PUSCH_AVG
RSSI_PUCCH_AVG SINR_PUCCH_AVG
format 0 associated with a new
packet transmission.
Qrxlevmin:
Specifies the minimum
required RX RSRP level in the
cell.
T300:
Timer T300 supervises the
RRC connection establishment
procedure.
T301:
Timer T301 supervises the
RRC connection reestablishment procedure.
T310:
Timer T310 supervises the
recovery from physical layer
problems.
T311:
Timer T311 supervises the
RRC connection reestablishment.
N310:
This is the maximum number
of consecutive "out of sync"
indications received from lower
layers.
N311: Maximum number of
consecutive "in-sync"
indications received from lower
layers.
nCqiDtx: The parameter
defines the number of
consecutive CQI DTX
detections causing radio link
failure indication.
dlSrbCqiOffset: Provides the
CQI link adaptation offset
applied to downlink
transmissions containing
SRB1 messages.
The more negative the value,
the more conservative the
MCS and PDCCH aggregation
level will be for the downlink
SRB1 message transmissions.
a3Offset: low values handover earlier; high values delay the handover.
hysA3Offset:low values - pingpong HO; High values - delay
the HO a& possible lead to lost
connection to the serving cell.
a3TimeToTrigger: low values ping-pong HO; High values delay the HO a& possible lead
to lost connection to the
serving cell.
tS1RelPrepL : Timer is
started when Source eNB
sends S1AP:Handover
required message to MME and
it is stopped when S1AP
Handover Command or S1AP
Handover preparation failure.
INITIAL LTE KPI TROUBLESHOOTING METRICS - HUAWEI
ACCESSIBILITY
RETAINABILITY
Measure of the ability of a user
to obtain an E-RAB from the
system.
The Initial E-RAB
Establishment process can be
divided into the following
phases:
Measure of the ability of a user
to retain the E-RAB once
connected, for the desired
duration.Call drops are also
referred as Radio Link
Failures (RLF).
1.RRC CONNECTION
ESTABLISHMENT
2.S1 SIGNALING
CONNECTION
ESTABLISHMENT
3.INITIAL E-RAB
ESTABLISHMENT OR E-RAB
ADDITION
RRC Success Rate KPI:
This message contains the
objective of the connection and
based on that it is subdivided
into following major categories:
Mo-data : Usually used for UE
coming back from idle mode if
it has data to send or if it has
to make a call
Mo-signaling : Most
commonly observed for TAUs
and Attach messages
Mt-access : Idle UE responds
to a paging message
Emergency
High Priority Access
RRC -Possible Causes of
degradation
Resource allocation
fail,Noreply from UE,SRS
Resource allocation
fail,PUCCH Resource
allocation fail,Discarded to flow
control
S1 Signalling -Possible
Causes of degradation
Transport issue,Wrongly
Configured TAC,Degraded due
to H/W Issue
ERAB -Possible Causes of
degradation
Radio network fail, Transport
network fail, Radio resouce not
available, Noreply from UE(UE
LOST), sync to unsync,
S1reset eNodeB or MME,
unsync
Failure Counters for RRC:
L.RRC.SetupFail.ResFail
L.RRC.SetupFail.Noreply
L.RRC.SetupFail.Rej
L.RRC.SetupFail.ResFail.SRS
L.RRC.SetupFail.ResFail.PUC
CH
L.RRC.SetupFail.Flowcontrol
L.RRC.connreq.Msg.disc.Flow
control
L.RRC.ReEst.ReconfFail.Reg
L.RRC.ReEst.HOFail.Reg
L.RRC.ReEst.ReFail
L.RRC.ReEstFail.Noreply
L.RRC.ReEstFail.Rej
L.RRC.ReEstFail.NoCntx
Failure Counters for ERAB:
L.ERAB.FailEst.MME
L.ERAB.FailEst.NoRadioRes
L.ERAB.FailEst.Noreply
L.ERAB.FailEst.RNL
L.ERAB.FailEst.TNL
MOBILITY
UE moves from one eNB to
target eNB while keeping its
connected state. LTE Services
will be uninterrupted.
Preparation – The Source
eNodeB sends a request to the
Target eNodeB, which
The E-RAB Retainability QCI performs admission control
Execution – After successful
drops per second and
percentage KPIs represent the preparation, the Source
eNodeB sends a handover
number of abnormal active
command to the UE
releases initiated by the
EnodeB and the MME.
Mobility Issues
Preparation Phase
Retainability Issues
1.Admission control
1.Missing neighbor relations
2.TAC issue
2.Poor radio conditions
3.X2 link unable or not defined
3.Badly tuned handover
4.Late HO + Early/Ping Pong
parameters
5.S1 Interface failure
4.Problem with scheduler
6.One way NBRs
algorithms
5.Admission reject, due to lack
of licenses
Execution Phase
6.Alarm
1.Downlink coverage
2.Interference
Failure counters:
3.Timer
L.E-RAB.AbnormRel.HOFail
4.PCI
L.E-RAB.AbnormRel.MME
CONFUSION/COLLISION
L.E-RAB.AbnormRel.Other
5.Cell range issue
L.E-RAB.AbnormRel.Radio
6.Alarm
L.E-RAB.AbnormRel.TNL
Failure Counters:
L.HHO.InterFddTdd.Prep.FailIn.
Parameters tuning for Call
AdmitFail
Drops:
L.HHO.InterFddTdd.Prep.FailIn.
Ueinactivitytimer
AdmitFail.Load
T310
L.HHO.InterFddTdd.Prep.FailIn.
p0NominalPusch/PUCCH
AdmitFail.Other
rrcConnReestActive
L.HHO.InterFddTdd.Prep.FailIn.
N310 - 2 to 6
AdmitFail.UserLic
T310 - 500ms to 1000ms
L.HHO.Prep.FailIn.AdmitFail.Loa
RLC retransmission threshold - d
8 to 16
L.HHO.Prep.FailIn.AdmitFail.Oth
er
L.HHO.Prep.FailIn.AdmitFail.Use
rLic
L.HHO.X2.Prep.FailIn.Unknown
MmeCode
L.HHO.X2.InterFddTdd.Prep.Fail
1.Radio Induced Call Drops In.UnknownMmeCode
L.HHO.X2.Prep.FailOut.HOCanc
el
DL RLC Retransmissions:
L.HHO.X2.Prep.FailOut.MME
The most common drop
L.HHO.X2.Prep.FailOut.NoReply
pegged under Radio issues is
L.HHO.X2.Prep.FailOut.PrepFail
the drop due to RLC
ure
retransmissions.
L.HHO.X2.Prep.FailOut.PrepFail
If a network has a maximum of ure.UnknownMmeCode
16 RLC retransmissions for
L.HHO.X2.Prep.FailOut.TargetIll
downlink, the eNB will send a egal
Common Causes for Call
Drops
Radio Induced Drops
MME Induced Drops
message 16 times at the RLC
layer and if the UE is unable to
decode it or send an
acknowledgement, the eNB
will consider this a RLF
Optimization:
1.Due to coverage and quality
problems.
2.Improve radio conditions
which is usually done with
physical optimization.
3.Increasing RLC
retransmission threshold to a
higher value.
Handover Execution Failure:
In this case, the UE will wait for
a specific time as per T304
and once T304 expires, it will
initiate a RRC
ReEstablishment with the
Admission control
fail/Congestion AC fail lead
bad HO with specific targets
not all NBR Relations.
Solution:
Need to check Specific NBR
Relation
balanced traffic between LTE
carries
offload with NBRs
PCI Collision/Confusion
handover fails due to timer
expire or high execution failure.
Solution: Re-Plan PCI/RSI
INTEGRITY
User data speed in Mbps /
Throughtput in Bits per second.
C=B.LOG(1+S/N)
GOOD THROUGHPUT
CONDITION
1.RSSI- (< -105 DBM)
2.SINR- Value >= 20
3.PRB UTILIZATION- (<80%)
4.POWER RESTRICTED
TRANSPORT BLOCK-UL - (<
50%)
5.CQI-(>10)
6.MIMO RANK 2 TM2(PDF
RANGE 1) & TM3(PDF RANGE
2)
7.HIGH USAGE OF 64 QAM
AND 16 QAM SCHEME IN DL
8.Rank indicator (should be 2)
GOLDEN PARAMETERS
1.RbgAllocStrategy - RBG
Resource Allocation Strategy
GUI Value Range:
ROUND_DOWN, ROUND_UP,
ADAPTIVE
Recommended Value:
ADAPTIVE
Impact :Setting this parameter to
ADAPTIVE does not waste RBs
when the number of required
RBGs is less than 1.
2.pb - PB
Meaning: Indicates the scaling
factor index of the Energy Per
Resource Element (EPRE) on
the PDSCH. This scaling factor is
determined by the value of this
parameter and the antenna port.
GUI Value Range: 0~3
Recommended Value: SingleReasons for throughput
antenna: 0; double-antenna: 1
Degradation:
Impact : If the
BLER (bad coverage)
Downlink Interference (Bad CQI) ReferenceSignalPwr setting is
unchanged, a smaller value of Pb
MIMO Parameters
results in higher EPRE of
Scheduling algorithm
symbols that appear during a
Low Demand
symbol period in which there are
CQI reporting frequency
reference signals, higher power
Other (VSWR, Backhaul
for UEs in the local cell, and
capacity)
higher interference to
neighboring cells; a larger value
Throughput =(
leads to the opposite effects.
L.Thrp.bits.DL(bit)L.Thrp.bits.DL.LastTTI(bit) ) /
L.Thrp.Time.DL.RmvLastTTI(m 3.ReferenceSignalPwr Reference signal power
s) *1000
Meaning: Indicates the cell
reference signal power of each
Counters for troubleshoot
physical antenna. However, the
DL PRB Util(%)
cell reference signal power
UL PRB Uti(%)
delivered in SIB2 is that of each
PS BLER(%)
logical antenna.
Avg. CQI(%)
GUI Value Range: -600~500
L.ChMeas.RI.Rank1
Recommended Value: 182
L.ChMeas.RI.Rank2
Impact : 1) Coverage: If the value
UL RSSI(%)
is too large, cross-coverage
DL Latency (ms) GLD
occurs. If the value is too small,
TA(0 to 300Mtr)
coverage holes appear.
L.DLPwr.Avg(dBm)
2) Interference: The setting of
L.DLPwr.Max(dBm)
ReferenceSignalPwr varies with
L.HHO.PingPongHo
the interference from neighboring
L.Traffic.User.Max
cells.
3) Channel estimation: A larger
Action Plan for throughput
value leads to higher channel
improvement:
1. ALL Band High PRB Utilization estimation accuracy, a lower
demodulation threshold, and
: Throughput <3Mbps & Total
Traffic GB is HIGH - MLB tuning higher receiver sensitivity, but it
causes stronger interference to
Required
2. ALL Band High Traffic : Total neighboring cells.
4) Capacity: A larger value brings
Traffic GB > 100 GB (20Mhz
better coverage, but a large
Bandwidth) - Capacity
value limits the power used for
Addition/MLB tuning/Sector
the transmission of data and
Addition/H//-Massive MIMO
Plan/Band Addition/ Twin Beam hence decreases the system
capacity.
Addition
3. Good CQI. Medium PRB :
Basic hygenic need to check (
MLB tuning & Physical
Optimization recommended )
4. Traffic not balanced between
network layers : Physical Audit
required
5. Worst CQI : Physical
Optimization recommended
4.PaPcOff - PA for even power
distribution
Meaning: Indicates the PA to be
used when PA adjustment for
PDSCH power control is
disabled, DL ICIC is disabled,
and the even power distribution
is used for the PDSCH.
Recommended Value: Dualantenna or four-antenna:
MLB tuning parameters and
DB_3_P_A(-3 dB) / Singlethresholds:
1.INTERFREQLOADBASEDHO antenna: DB0_P_A(0 dB)
A4THDRSRP - Neighbor cell
Thresh for MLB
Incorrect Cellrange settings
between source & target.It will FDD : from -114 to -110
impact specific NBR not all
NBRs relations, Check HO Per
NBRs.
Solution:
Correct RACH cyclic shift &
PRACH index.
TDD : from -112 to -102 (10Mhz)
/ TDD : from -112 to -80 (20Mhz)
2.
INTERFREQMLBA1A2THDRSR
P - Serving Cell A1/A2 source
cell threshold
Impact : If the RS power is fixed,
setting this parameter to a large
value increases the transmit
power and MCS for all UEs in the
cell, which results in power
limitation and affects throughput.
L.RRC.ReEstFail.Rej
L.RRC.ReEstFail.NoCntx
Failure Counters for ERAB:
L.ERAB.FailEst.MME
L.ERAB.FailEst.NoRadioRes
L.ERAB.FailEst.Noreply
L.ERAB.FailEst.RNL
L.ERAB.FailEst.TNL
L.ERB.Num.Sync2unsync
L.ERAB.Rel.ENodeB
L.ERAB.Rel.MME
L.ERB.Rel.S1reset.eNodeB
L.ERB.Rel.S1reset.MME
L.ERAB.Rel.unsync
Accessibility & Retainability
– Parameter Summary
RRC Connected user license
- 300 to 1000
1.EnhancedRRCReestProtect
Thd
2.RrcReestOptSwitch
3.RrcConnPunishThd(0~100;0
)
4.DeprioritisationDeliverInd
5.T325
6.UlSynTimerForQci
7.UeInactiveTimerPri(0~255;0)
8.T300/301/302/304/310/311
9.UuMessageWaitingTimer
10.UuMessageWaitingTimerQ
ci1
11.UeMaxRetxThreshold
12.TimeAlignmentTimer
13.UeInactiveTimerQci1
T300 - Increase the timer value
Power Control Paramters:
P0NominalPUCCH; -127~-96;105
P0NominalPUSCH; -126~24;67
DeltaPreambleMsg3; Indicates
the power offset (delta value)
of message 3 relative to the
preamble. This power offset
has a step size of 2.; -2~12,
step:2;4
UePowerMax; Indicates the
maximum transmit power that
a UE can apply to uplink
transmission in the cell. ;30~36;23
PwrRampingStep;
DB0_PWR_RAMPING_STEP,
DB2_PWR_RAMPING_STEP,
DB4_PWR_RAMPING_STEP,
DB6_PWR_RAMPING_STEP;
DB2_PWR_RAMPING_STEP(
2dB)
PmchPwrOffset; Indicates the
offset of PMCH power to the
maximum PDSCH power.
PreambInitRcvTargetPwr;
DeltaMcsEnabled; Indicates
whether the transmit power of
the UE is adjusted according to
the difference between MCSs.
PassLossCoeff; Indicates the
compensation factor for path
loss. It is used in UL power
control.
retransmission threshold to a
higher value.
antenna or four-antenna:
handover fails due to timer
MLB tuning parameters and
DB_3_P_A(-3 dB) / Singleexpire or high execution failure. thresholds:
Solution: Re-Plan PCI/RSI
1.INTERFREQLOADBASEDHO antenna: DB0_P_A(0 dB)
Incorrect Cellrange settings
between source & target.It will
Handover Execution Failure: impact specific NBR not all
In this case, the UE will wait for NBRs relations, Check HO Per
a specific time as per T304
NBRs.
and once T304 expires, it will Solution:
initiate a RRC
Correct RACH cyclic shift &
ReEstablishment with the
PRACH index.
cause value of Handover
failure. Now, if this RRC
x2 interface missing or
ReEstablishment also fails and unable(Delete relation & ANR
the UE is unable to get a
will add)
connection, the source eNB
ANR trigger settings(RSRP
will release the context after
thresholds, number of NBRs
expiry of the internal timer.
etc)
This is the X2 Reloc Overall
Optimize Missing, one way &
Timer and the cause of this
max NBRs relation.
release will be X2 Reloc
Overall Expiry.
Mobility Improvement:
Optimization:
target cell is very far away. So, Missing neighbor relation:
the target cell fails to decode Fine tune the neighbor list on a
the dedicated RACH properly regular basis to rectify the
for this UE and it results in a
same.
handover failure.
Poor radio conditions:
1.Increase the cell radius of the Physical optimization of site
target cell or downtilt.
like changing antenna heights,
2.Large water bodies
tilts, azimuths,eNodeB power
3.Forbid handovers to such
etc can be used to improve the
cells
radio condition in a eNodeB
4.Add offsets for those cells.
Badly tuned handover
parameters like:
Drop Due to No Response:
Abnormal release before
If an eNB sends a signalling
handover.
message for instance RRC
Handover hysteresis and timeReconfiguration then it expects to-trigger settings
a response from the UE. If the Rural and fast changing
UE does not send a RRC
environments have different
Reconfiguration Complete
requirements. This tuning
message to the eNB and the
should be based on UE
internal timer on the eNB
measurements during drive
expires, then the eNB initiates tests.
a release. This timer is usually Right overlap of cell.
a large value, so such a drop is
rare. If such drops are seen
Parameters for HOSR
then verify that the eNB’s
improvement:
internal timer is not set to a
Handovers – Parameters
very small value.
FreqPriorityHoSwitch
Actual Value Range:
Optimization:
FreqPriorIFHOSwitch,
Reduce UE inactivity timer.
FreqPriorIFBlindHOSwitch,
MlbBasedFreqPriHoSwitch,
2.MME Induced Drops:
A2BasedFreqPriHoSwitch,
LoadTriggerFreqPriHoSwitch
Uplink RLC Retransmission
SrvBasedInterFreqHoSw
Issue:
HOSR ANALYSIS
Consider a UE that
1.X2 link status unavailable –
experienced RLF due to
Need to enable X2 link on
maximum number of uplink
priority.
RLC retransmission.
2.Source S1 Link Status
Such a UE will initiate a RRC unavailable – Need to create
ReEstablishment procedure to S1 link at Source site.
regain its radio link.
3.Target S1 Link Status
Optimization:
unavailable – Need to create
Increasing the uplink RLC
S1 link at Target site.
retransmission threshold can 4.Magic box issue - Need to
help reduce such failures.
create Home EnodeB Profile
N310 PDCCH Decoding
on priority.
Failures:
5.Unknown target & Unknown
Optimization:
MME – Need to blacklist
Such issues can be reduced by unknown neighbours.
increasing the N310 & T310
6.Unspecified failures – ANR
value.
Reset required.
Handover Drop Due To MME: 7.Source & Target Site Alarm
Optimization:
– Fault Management team
optimization of neighbors and Support required for Alarm
verifying that functional X2
Clearance.
links are present for all the
8.Inter-Site distance >10km –
neighbors.
Need to blocklist long distance
neighbours or change Cell
individual offset.
A4THDRSRP - Neighbor cell
Thresh for MLB
FDD : from -114 to -110
TDD : from -112 to -102 (10Mhz)
/ TDD : from -112 to -80 (20Mhz)
2.
INTERFREQMLBA1A2THDRSR
P - Serving Cell A1/A2 source
cell threshold
FDD & TDD : from -90 to -60
3. InterFreqMlbSwitch : Enabled
for FDD & TDD
4. InterFreqBlindMlbSwitch :
Disabled for FDD & TDD
5. InterFreqIdleMlbSwitch :
Enabled for FDD & Disabled for
TDD
6. INTERFREQMLBTHD &
LOADOFFSET ( PRB Based
MLB Source cell threshold)
INTERFREQMLBTHD – FDD :
25 / TDD : 80
LOADOFFSET – FDD & TDD :
from 5 to 0
7. LOADDIFFTHD - FDD & TDD
: from 15 to 2
8. MLBTRIGGERMODE - FDD &
TDD : PRB_OR_UE_NUMBER
9. INTERFREQMLBUENUMTHD
& MLBUENUMOFFSET ( UE
Based MLB )
INTERFREQMLBUENUMTHD –
FDD : from 6 to 7 / TDD : from 20
to 36 (10Mhz) / TDD : from 45 to
66 (20Mhz)
MLBUENUMOFFSET – FDD: 2 /
TDD: 4
10. MLBMAXUENUM - FDD &
TDD : from 20 to 40
11. MLBUESELECTPRBTHD FDD & TDD : from 20 to 0
12. UEULPRBLOWTHDOFFSET
- FDD & TDD : from 0 to 90
13. MLBMINUENUMTHD - FDD :
from 0 to 7 / TDD : from 0 to 15
(10Mhz) / TDD : from 0 to 30
(20Mhz)
14. MLBMINUENUMOFFSET –
FDD & TDD: 0
15. INTERFREQUETRSFTYPE
– FDD : SynchronizedUE1&IdleUE1&PrbMlbSynchronizedUE1&PrbMlbIdleUE-1 / TDD:
SynchronizedUE-1&IdleUE0&PrbMlbSynchronizedUE1&PrbMlbIdleUE-0
16.
INTERFREQLOADEVALPRD FDD & TDD: 10
17. FREQSELECTSTRATEGY –
FDD & TDD: PRIORITYBASED
to LOADPRIORITY
18. PRBLOADCALCMETHOD FDD & TDD: PRB_USAGE
19.
MLBUESELECTPUNISHTIMER FDD & TDD: 120 to 0
20. PUNISHJUDGEPRDNUM FDD & TDD: 1
21. FREQPUNISHPRDNUM FDD & TDD: 4 to 1
22. CELLPUNISHPRDNUM FDD & TDD: 4 to 1
23. MLBTRIGJUDGEPERIOD FDD & TDD: 5 to 1
24.
INTERFREQMLBSTRATEGY FDD & TDD:
WEIGHTEDUENUM-0 to
WEIGHTEDUENUM-1
25. FreqPriorIFHOSwitch - FDD
& TDD: Disabled
Impact : If the RS power is fixed,
setting this parameter to a large
value increases the transmit
power and MCS for all UEs in the
cell, which results in power
limitation and affects throughput.
Setting this parameter to a small
value decreases the transmit
power and MCS for all UEs in the
cell but reduces cell throughput.
5.PDCCH Symbol Number
Adjust Switch - PDCCH
Symbol Number Adjust Switch
GUI Value Range: OFF(Off),
ON(On),
ECFIADAPTIONON(Enhanced
CFI Adaption On)
Recommended Value:
ECFIADAPTIONON
Impact : If this parameter is set to
ECFIADAPTIONON, the dynamic
adjustment of the number of
OFDM symbols occupied by the
PDCCH considers cell downlink
throughput, and therefore can
reach higher throughput when
downlink frequency selective
scheduling is enabled.
6.PdcchCapacityImproveSwitc
h - PDCCH Capacity Improve
Switch
GUI Value Range: OFF(Off),
ON(On)
Recommended Value: On
Impact : For LTE FDD networks,
if this parameter is set to
ON(On), (1) the initial value for
closed-loop adjustment on
PDCCH aggregation level
decreases and PDCCH capacity
increases, and therefore cell
throughput increases; (2) the
CCE allocation success rate
increases, and therefore cell
throughput increases.For LTE
TDD network, if this parameter is
set to ON(On), the CCE
allocation success rate
increases, and therefore cell
throughput increases.
7.MimoAdaptiveSwitch - MIMO
Adaptive Switch
GUI Value Range:
NO_ADAPTIVE(NO_ADAPTIVE)
,
OL_ADAPTIVE(OL_ADAPTIVE),
CL_ADAPTIVE(CL_ADAPTIVE),
OC_ADAPTIVE(OC_ADAPTIVE)
Recommended Value:
CL_ADAPTIVE
Impact : If this parameter is set to
NO_ADAPTIVE, the eNodeB
uses the fixed MIMO
transmission mode specified by
the FixedMimoMode parameter
for UEs in the downlink.
8.HoppingOffset - Hopping
offset
Meaning: Indicates the hopping
offset of the PUSCH.
GUI Value Range: 0~98
Recommended Value: 0
The value 0 indicates that this
parameter is not supported by
cells with specific bandwidths.,
whereas the value
DS1_DELTA_SHIFT is not
supported by cells with the
extended CP length.
INITIAL LTE KPI TROUBLESHOOTING METRICS - ERICSSON
ACCESSIBILITY
RETAINABILITY
Measure of the ability of a Measure of the ability of a user
user to obtain an E-RAB to retain the E-RAB once
connected, for the desired
from the system.
duration.Call drops are also
The Initial E-RAB
referred as Radio Link
Establishment process
Failures (RLF).
can be divided into the
following phases:
1.RRC CONNECTION
ESTABLISHMENT
2.S1 SIGNALING
CONNECTION
ESTABLISHMENT
3.INITIAL E-RAB
ESTABLISHMENT OR E-RAB
ADDITION
Accessibility issues
Poor coverage
Alarms
High Load (High Traffic)
H/W issue (Hard Reset on site
/ RRU Replacement, if
required)
High UL interference
PCI conflict
RACH Root Sequence Index
plan need to be reviewed
UE camping in the wrong cell.
Cell Reselection Parameters
need to be tuned
Wrong System constant
setting(SC-556)
VSWR over threshold
Cell availability
Failures Counters for RRC:
pmRrcConnEstabFailLic
pmRrcConnEstabFailHighLoad
pmRrcConnEstabFailOverload
pmRrcConnEstabFailActiveUs
erLicenseExceeded
pmRrcConnEstabFailFailureIn
RadioProcedure
pmRrcConnEstabFailBearerAd
missionRej
pmRrcConnReestFailLicMtRee
st
pmRrcConnEstabFailLackOfR
esources
pmRrcConnEstabFailUnspecifi
ed
MOBILITY
UE moves from one eNB to
target eNB while keeping its
connected state. LTE Services
will be uninterrupted.
Preparation – The Source
eNodeB sends a request to the
Target eNodeB, which
The E-RAB Retainability QCI performs admission control
Execution – After successful
drops per second and
percentage KPIs represent the preparation, the Source
eNodeB sends a handover
number of abnormal active
command to the UE
releases initiated by the
EnodeB and the MME.
Mobility Issues
Preparation Phase
Retainability Issues
MME pool should be same.
1.OSS Alarm
SpidHoWhiteList is active on
2.UL Interference
the target, which has
3.ERAB Abnormal release
primaryplmnReserved set to
causes
true.
4.UE Context Abnormal
Target cell is overloaded (High
release causes
capacity)
5.MME Abnormal release
Target cell Unavailable : The
6.Mobility causes
target cell is down / disabled
7.CTR and UETR analysis
TAC not defined on site, as per
8.Poor coverage*
network design
9.High Load (high traffic)*
License issue/Software issue.
10.H/W issue (Re-set first) if
Target cell has a fault (alarm,
required replace RRU*
disabled cell, etc.)
11.VSWR over threshold*
Site Configuration issue.
Failure Counters:
ENODEB INITIATED E-RAB
2-Execution Phase
RELEASE:ANR PCI Conflict (Collision &
pmErabRelNormalEnb
Confusion)
pmErabRelAbnormalEnbAct
Target exceeds cell range
MME INITIATED E-RAB
Target is a sleeping cell
RELEASE:Target has high uplink
pmErabRelMme
interference
pmErabRelMmeAct
Poor RF conditions
1.pmErabRelAbnormalEnbA
Parameters for improving
ctCdt – The total number of
intra LTE HOSR:
abnormal ERAB releases by
the eNB per cell due cell down cellindividualoffsetEutran
hysteresisA3
time (manual intervention)
timeToTriggerA3
Probable Solutions : - Check
Outage report
2.pmErabRelAbnormalEnbA Parameter tuning for Inter
LTE HOSR:
ctHo – The total number of
abnormal ERAB releases per a5Threshold1RSRP/-107
a5Threshold2RSRP/-115
cell by the eNB due to
hysteresisA5/10
handover execution failure
timeToTriggerA5/480
Probable Solutions:- Check
PCI Planning,Coverage
If MCPC enabled, then the
issue.Make EDT, Change
following parameters are
Azimuth
High UL Interference issue on used:
a1a2SearchThresholdRsrp/Target cell
(PmRadiorecInterferencePwr). 103
hysteresisA1A2SearchRsrp/20
Check Connection b/w
Antenna Connector & RRU
Major reasons / causes behind
Connector.
Also Repeater is responsible poor IRAT handover success
rate are as follows : sometimes for Hi-UL
Interference. Might be due to Coverage gap between LTE &
3G/Other Technology.
Power Leakage.
3.pmErabRelAbnormalEnbA Improper parameter setting:
ctUeLost – The total number a1a2SearchThresholdRsrp
of abnormal ERAB releases by from -110 dBm to -112 dBm
b2Threshold2RscpUtra from the eNB per cell due that the
115 dBm to -105 dBm
contact with the UE is lost
a2CriticalThresholdRsrp from Probable Solutions:Solve the Poor Coverage issue 122 dBm to -124dBm
by changing tilt / azimuth or
INTEGRITY
User data speed in Mbps /
Throughtput in Bits per
second.
C=B.LOG(1+S/N)
GOOD THROUGHPUT
CONDITION
1.RSSI- (< -105 DBM)
2.SINR- Value >= 20
3.PRB UTILIZATION- (<80%)
4.POWER RESTRICTED
TRANSPORT BLOCK-UL - (<
50%)
5.CQI-(>10)
6.MIMO RANK 2 TM2(PDF
RANGE 1) & TM3(PDF
RANGE 2)
7.HIGH USAGE OF 64 QAM
AND 16 QAM SCHEME IN DL
8.Rank indicator (should be 2)
FORMULAS INFO
Initial E-RAB Establishment
Success Rate:
RRC Succ Rate =
(pmRrcConnEstabSucc/pmRrc
ConnEstabAttpmRrcConnEstabReAtt)*100
S1 Sign Succ Rate =
(pmS1SigConnEstabSucc/pm
S1SigConnEstabAtt)*100
Erab Estab Succ Rate =
(pmErabEstabSuccInit/
pmErabEstabAttInit)*100
E-RAB Drop =
((pmErabRelAbnormalEnbAct
+
pmErabRelAbnormalMmeAct)
/ (pmErabRelAbnormalEnb +
Total Performance - Check all pmErabRelnormalEnb +
important Accessibly, Mobility pmErabRelMme)) *100
and Retainability KPI
HO Preparation Succ Rate =
RRC Connected Users - Dl
((pmHoPrepSuccLteIntraF +
Throughput would reduce with pmHoPrepSuccLteInterF) /
increase in number of
(pmHoPrepAttLteIntraF +
connected users.
pmHoPrepAttLteInterF)) *100
CQI ,64/16QAM,TM Modes
Av CQI, % 64QAM samples
and RI indicates DL SINR
status. Average CQI should be
high (>10%), % of 64QAM
sample should be high (>10%),
PRB(DL) And PDCCH
Utilization - High PRB and
PDCCH utilization would
impact the DL Throughput
DL Latency And RLC
Retransmission - High value
of DL latency(>9ms) and RLC
retransmission(> 1%) would
impact DL throughput.
Power Limited UE And No
Of A2 Events - High
occurrence of
pmRadioTbsPwrRestricted and
pmBadCovEvalReport
indicates poor DL coverage.
HO Execution Succ Rate =
((pmHoExeSuccLteIntraF +
pmHoExeSuccLteInterF) /
(pmHoExeAttLteIntraF +
pmHoExeAttLteInterF)) *100
DL Average UE
Throughput(Mbps) =
(pmPdcpVolDlDrb –
pmPdcpVolDlDrbLastTTI +
pmPdcpVolDlDrbTransUm) /
pmUeThpTimeDl
UL Average UE
Throughput(Mbps) =
pmPdcpVolUlDrb /
pmUeThpTimeUl
Throughput Calculation:
Lets’ assume we have 20 MHz
channel bandwidth.
we need to calculate the
resource elements in a
Counters for S1 fails:
subframe for this band i.e.
pmS1SigConnEstabFail
12subcarriers x 7 OFDMA
Alarm & Parameter/ Feature
symbols x 100 resource blocks
Check
Counters for ERAB Setup
x 2 slots= 16800 REs per
fails:
RSSI - High uplink RSSI would subframe.
pmErabEstabFailGbrDlEnb
Assume we have 64 QAM
impact the throughput.
pmErabEstabFailGbrUlEnb
modulation and no coding, one
pmErabEstabFailAddedLic
% of 16 QAM samples - Low modulation symbol will carry 6
pmErabEstabFailInitLic
usage of 16 QAM modulations bits.
16800 modulation symbols x 6
scheme in UL would impact
Troubleshooting for CFR:
bits / modulation symbol =
the UL throughput
High load – offload the traffic
100800 bits.
Implementation of Hi-Cap
So, the data rate is 100800 bits
PUCCH & PUSCH SINR Parameter (if Max RRC Conn
/ 1 ms = 100.8 Mbps.
Poor UL SINR conditions
Users is more than
would impact UL throughput. With 4×4 MIMO, the peak data
rate goes up to 100.8 Mbps x 4
150/sector and
= 403 Mbps.
pdcchutil>70% )
Power limited UE - High
Estimate about 25% overhead
If still traffic load is more,
number of power limited UE
new site integration and
indicates poor uplink coverage. e.g. PDCCH, reference signal,
sync signals, PBCH, and some
deployment plan is
We get 403 Mbps x 0.75 = 302
submitted
Mbps.
appropriate parameter value
BLER (bad coverage)
Failure Counters:
setting
Downlink Interference (Bad
THROUGHPUT
License Counters
E.g. : - partOfSectorPower,
CQI)
dlMaxRetxTh of SRB1
TROUBLESHOOTING:
ENB Power, P0NominalPucch pmHoPrepRejInLicConnUsers MIMO Parameters
ULMaxRetxTh of SRB1
Scheduling algorithm
pZeroNominalPucch: From - / P0NominalPusch (for uplink pmHoPrepRejInLicMob
pmHoPrepRejInLicRlcUm
Check whether the block error
Coverage).
Low Demand
120 to -117
rate (BLER) is excessively high
High UL NI Issue(As per earlier pmHoPrepRejInLicMultiErab
pdcchutil>70% )
If still traffic load is more,
new site integration and
deployment plan is
submitted
dlMaxRetxTh of SRB1
ULMaxRetxTh of SRB1
pZeroNominalPucch: From 120 to -117
pZeroNominalPusch: From 106 to -102
qRxLevMin : from -120 to 114
MCPC feature need to enable
for poor coverage
connected users license
Change from 1000 to 2000
The following KPIs need to
be closely monitored, once
the required changes for HI
CAP Settings are
implemented:
RACH Success Rate.
Accessibility and Retainability.
Max and Average RRC
Connected UEs.
High/Over load.
Handover performance.
UL/DL Throughput.
CCE utilization.
HI-CAP Parameters:
ulMaxRetxThreshold - set to
8 (reduces the number of
uplink RLC retransmissions for
signaling radio bearer and data
radio bearer)
tPollRetransmitDl - set to 160
ms (It extends the downlink
time for new poll if no status
report is received for both
signaling radio bearer and data
radio bearer )
tPollRetransmitUl - set to
160ms (It extends the uplink
time for new poll if no status
report is received for both
Signaling Radio Bearer and
Data Radio Bearer. The
changes will reduce SE/TTI
usage for retransmissions, and
allow more SE/TTI to serve
traffic)
deltaPsdRs2Tx - (3dB) to
(0dB) (RS power boost is
reduced for inter-site/cell
interference under low Inter
Site Distance (ISD) RF radio
environment)
numInitialAccessAndIncomi
ngHo - is changed from a
Global 10 to Local 10 or 20 (It
reduces the maximum number
of initial accesses and
incoming handovers that are
allowed during a time window
without triggering the load
control mechanism )
pdcchLaGinrMargin - set to
30 (3dB) (This reduces
PDCCH link adaption
algorithm from 10db to 3 db .
3dB is a reasonable
compromise between saving
CCE resources and ensuring
reception of PDCCH by the
UE)
= 403 Mbps.
a2CriticalThresholdRsrp from - Power limited UE - High
Probable Solutions:Estimate about 25% overhead
Solve the Poor Coverage issue 122 dBm to -124dBm
number of power limited UE
by changing tilt / azimuth or
indicates poor uplink coverage. e.g. PDCCH, reference signal,
sync signals, PBCH, and some
We get 403 Mbps x 0.75 = 302
Mbps.
appropriate parameter value
BLER (bad coverage)
Failure Counters:
setting
Downlink Interference (Bad
THROUGHPUT
License Counters
E.g. : - partOfSectorPower,
CQI)
TROUBLESHOOTING:
ENB Power, P0NominalPucch pmHoPrepRejInLicConnUsers MIMO Parameters
/ P0NominalPusch (for uplink pmHoPrepRejInLicMob
Scheduling algorithm
pmHoPrepRejInLicRlcUm
Check whether the block error
Coverage).
Low Demand
rate (BLER) is excessively high
High UL NI Issue(As per earlier pmHoPrepRejInLicMultiErab
CQI reporting frequency
on the radio interface. If the
mentioned. Also make sure
Other (VSWR, Backhaul
BLER is higher than 10%, the
Nominal power Should not set Coverage Evaluation
capacity)
channel condition is poor and
very high otherwise it will
Counters
will result in low throughput.
create interference in
pmBestCellEvalReport
Counters for troubleshoot
Check whether uplink
neighbour cell).
pmBadCovEvalReport
pmRrcConnMax
interference exists, in a normal
4.pmErabRelAbnormalEnbLi pmHoOscIntraF
pmPrbUtilDl / pmPrbUtilUl
case, the UL RSSI on each
c – The total number of
pmHoOscInterF
pmBadCovEvalReport
pmMeasMissingNeighRel
abnormal E-RAB Releases
pmRadioRecInterferencePwrP resource block (RB) is about (
initiated by the RBS due to
UCCH/pmRadioRecInterferenc – {119 to 120} ) dBm when the
cell is unloaded. If the RSSI is
IRAT MCPC FEATURE:
license reject (per cell).
ePwr
3 dBm to 5 dBm higher than
5.pmErabRelAbnormalEnbA featureStateStateMobCtrlAtP pmsinrpucchdistr &
the normal value (when unctTnFail – The total number of oorCov - provides information pmsinrpuschdistr
loaded), uplink interference
abnormal ERAB releases per about the licensed feature –
pmRlcArqUlack /
exists. Locate the interference
cell due to S1 interface down, Mobility Control At Poor
pmRlcArqUlNack
source, and mitigate the
"X2 interface down" or
Coverage. The feature needs pmSchedActivityCellDl
interference (Could be some
"Transport Resource
to be set to 1.
/pmSchedActivityUeDl
external interferer or values of
Unavailable
pmRadioTxRankDistr
Probable Solutions : - Issue
serviceStateStateMobCtrlAtP pmRadioTbsPwrRestricted/pm pZeroNominalPusch in
neighbour cells are too high)
can be resolved with the help oorCov - Indicates the
RadioTbsPwrunRestricted
of NOC / IM Team by raising
licensed feature Mobility
pmMacHarqDlAck16qam/64qa Check whether the eNodeB’s
parameter settings are correct.
the required tickets.
Control At Poor Coverage. The m/Qpsk
6.pmErabRelAbnormalEnbA feature needs to be set to 1.
pmMacHarqDlNack16qam/64q If the values are inconsistent,
confirm whether the settings
ctHpr – The total number of
am/Qpsk
abnormal ERAB releases by
mobCtrlAtPoorCovActive pmMacHarqUlFail16qam/Qpsk are customized for the operator
the eNB per cell due to
Specifies if the feature Mobility pmMacHarqUlSucc16qam/Qps or have been changed to
incorrect values
handover preparation
Control at Poor Coverage is
k
Check whether the number of
Probable Solutions:enabled or disabled in the cell.
users in the cell is excessively
MME missing issue or MME
The parameter needs to be set Parameters for throughput
large. If an excessively large
might be disabled.
to TRUE.
improvement:
number of users have
Transport issue suspected.
accessed the cell and ENodeB
License issue suspected.
a1a2SearchThresholdRsrp - dlMaxRetxThreshold
Site Configuration issue.
The Reference Signal
(DRB/SRB) - 8/8 – Reduce the are exhausted when a UE
Received Power (RSRP)
no. of RLC retransmission for accesses the cell, the user
throughput will be low.
DL/UL MAXRETXTHDRB:
threshold value for events
SRB/DRB in DL.
Check whether relative license
dl maxRetxthdrb from 8 to 32 A1Search and A2Search. For
information is incorrect and if
ul maxRetxthdrb from 8 to 32 single-carrier sites,
ulMaxRetxThreshold
a1a2SearchThresholdRsrp
(DRB/SRB) - 8/8 - Reduce the the license has not expired
tinactivity timer value is
replaces a2ThresholdRsrpPrim no. of RLC retransmission for Check whether the traffic
volume to the eNodeB is
changed from 61s to 20s
parameter. It needs to be set to SRB/DRB in UL.
insufficient. A common reason
-116 for intraLTE, -112 for
for the insufficient input traffic
a3offset : Change from 3 to 2 interRAT_10 and -110
tPollRetransmitDl
volume is a bottleneck
interRAT_5.
dB
(DRB/SRB) –
transmission bandwidth at an
a2TresholdRsrpPrim :
160msec/1600msec.
intermediate node.
a2CriticalThresholdRsrp Change from -120 to -110
The Reference Signal
dBm.
noOfPucchsrUsers – 590 RBS Parameter Settings
Received Power (RSRP)
Max no. of PUCCH users is
EUtranCellFDD
a3Offset = 3 dB, hysteresis = threshold value for event
used
dlChannelBandwidth /
A2Critical. The
performed once Neighbor Cell a2CriticalThresholdRsrp
noOfPucchCqiUsers – 320 - dlChannelBandwidth
(nrOfSymbolsPdcch) (Control
parameter replaces
RSRP > 4dB of Serving Cell
Max no. of PUCCH users is
Region Size)
a2ThresholdRsrpSec. The
RSRP
used
A3 setting, A3 event handover setting for
controls whether OLSM MIMO
a2CriticalThresholdRsrp is will be performed when
deltaPsdRs2Tx – 0dB –
is used (2) or not.
122 for all sites.
neighbor cell is greater than
Change RS Power boost to
a3Offset + hysteresis (RSRP)
reduce DL inference and
this is the % part of RU
timeToTriggerA2Critical of the current serving cell.
shrink coverage.
capability independent of
The time-to-trigger value for
measurement in event
If retransmission limit
PdcchLaGinrMargin – 3dB – SectorEquipmentFunction::con
A2Critical. This parameter is
increases from 8 to 32, RL
Reduce PDCCH link adaption fOutputPower settings
set to 1280ms for all sites.
failure due to retransmission
algorithm from 10db to 3 db.
UEs need this to be increased
limit reached:
timeToTriggerB2 - The time QciProfilePredefined.schedu or ACK/NACKs are not
SRB: 360ms (8) to 1440ms
received successfully on
to trigger value for the eventB2 lingAlgorithm – Favor user
(32)
PUCCH.
measurement. Set to 1280ms with better CQI in order to
DRB: 400ms (8) to 1600ms
for all sites.
(32)
increase the utilization of less
UEs need this to be increased
robust MCS Values.
from default or lots of errors
Retainability issue due to HO
seen on PUSCH
failure:
UL THROUGHPUT
Need to tune
cellindividualoffset
pzeronominalpucch (-120dBm
to -117dBm)
pzeronominalpusch (-102dBm
to -98dBm)