Contenu connexe
Similaire à 60936529 55241452-kpi-3 g-3[1] (20)
60936529 55241452-kpi-3 g-3[1]
- 4. All Rights Reserved © Alcatel-Lucent 2008
CS Call set up diagram
Source: T Mobile documentation (
Public)
- 5. All Rights Reserved © Alcatel-Lucent 2008
PS Call set up diagram
Source: T Mobile
documentation ( Public)
- 6. All Rights Reserved © Alcatel-Lucent 2008
Accessibility
Ability of user to obtain the requested service from the system.
RRC ( Radio Resource Control)
RAB ( Radio Access Bearer)- defines type of service
Main KPIs
CSV Access Failure Rate, CSD Access Failure Rate, PS Access Failure Rate,
HSDPA Access Failure Rate, HSUPA Access Failure Rate, CS RAB set up success
ratio, PS RAB set up success ratio, RRC Congestion Ratio
- 7. All Rights Reserved © Alcatel-Lucent 2008
Voice Access
Failure
CS Voice RRC
Failure
Voice RAB
Failure
CS RRC
Setup or
RRC
Access?
RRC or
RAB?
CS RRC Setup
Failure
CS RRC Access
Failure
Voice RAB
Setup Failure
Voice RAB
Access Failure
Voice RAB Setup
or RAB Access?
RRC
Failure
/ Adm
Control
RRC
Failure
/ Adm
Control
RRC
Failure
/
License
RRC
Failure
/
License
RAB
Failure
/ DL
Code
RAB
Failure
/ DL
Code
RRC&RAB
Failure /
TN
Blocking
RRC&RAB
Failure /
TN
Blocking
RAB
Failure
/ DL
Pwr
RAB
Failure
/ DL
Pwr
RAB
Failure /
Hardwar
e
Resource
RAB
Failure /
Hardwar
e
Resource
RRC&RAB Setup
Failure Cause
Analysis
RRC Access Failures are mostly due to radio reasons. RAB Access Failures are
due to both radio and core network reasons.
Troubleshooting flow chart
- 9. All Rights Reserved © Alcatel-Lucent 2008
Failure causes
RRC failures causes:
Admission control.
Uplink issues.
RAB failures.
Admission control: Main causes : power, codes, Channel elements.
Example of Mumbai circle with wrong test license loaded on 2 cells. CE
capacity increased from 30 to 192.
- 10. All Rights Reserved © Alcatel-Lucent 2008
Example # 1 ( Accessibility)
Alarm: System dynamic traffic
exceeding licensed limit
- 11. All Rights Reserved © Alcatel-Lucent 2008
Remedial action
Congestion- EDT/MDT, CPICH ( only when absolutely necessary) for
power, addition of HW for codes, checking SW licenses for Channel
elements.
- 12. All Rights Reserved © Alcatel-Lucent 2008
Retainability
Ability of a user to retain its requested service for the desired duration
once connected.
Key issues are missing neighbors, low quality, Hw issues and alarms,
Transport issues.
Main KPIs:
CSV Drop Rate, CSD Drop Rate, HSDPA Call drop ratio, HSUPA call drop
ratio, PS R99 call drop ratio.
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Drop CauseDrop Cause
Voice Drop
Missing
Neigh
Missing
Neigh
RL Add
Failure
RL Add
Failure
UL SychUL Sych
IRAT
Drop
IRAT
Drop
Iur Drop
Other
Drop
Other
Drop
Analyze
existing
neighbors
with 3G-3G
cell relation
report
Analyze
existing
neighbors
with 3G-3G
cell relation
report
Analyze cell
coverage by
RF Planning
tool or
Drivetest
Analyze cell
coverage by
RF Planning
tool or
Drivetest
Down tilts
or other
physical
optimizatio
n
Down tilts
or other
physical
optimizatio
n
Check BTS
HW Alarms
Check BTS
HW Alarms
Check
Transmissio
n Errors
Check
Transmissio
n Errors
Check Cell
Availability
Check Cell
Availability
Investigatin
g the UE
TxPwr by
using
Drivetest
Investigatin
g the UE
TxPwr by
using
Drivetest
Analyze
cell
coverage
by RF
Planning
tool or
Drivetest
Analyze
cell
coverage
by RF
Planning
tool or
Drivetest
determine
the number
of Event 6a
or number
of Event 2d
determine
the number
of Event 6a
or number
of Event 2d
Neighbor
List
cleaning/
deletion
Neighbor
List
cleaning/
deletion
GSM
coverage
area
verification
for IRAT
neighbors
GSM
coverage
area
verification
for IRAT
neighborsRe-
prioritizatio
n the
neighbor
list based
on usage
Re-
prioritizatio
n the
neighbor
list based
on usage
Transport
Issue
Transport
Issue
RBS / RNC
HW issue
RBS / RNC
HW issue
RF issues
outside of
provided
counters
RF issues
outside of
provided
counters
UE issuesUE issues
Check Iur
drop per Iur
link
Check Iur
drop per Iur
link
Check
neighbor
cell
availability
Check
neighbor
cell
availability
- 15. All Rights Reserved © Alcatel-Lucent 2008
Sample formula:
CS service drop ratio= Number of CS RAB abnormal releases/Total no. of
CS RAB releases * 100%.
VP Call drop ratio= Number of VP RAB abnormal releases/Total no. of VP
RAB releases * 100%.
- 16. All Rights Reserved © Alcatel-Lucent 2008
Example # 2 ( Retainability)
Due to RF causes ( RL
synchronous failure)
Cell W_DL_Delhi_240_10@1 with CSV failure rate of 19% and voice traffic
of 0.53 E
Drill down:
- 17. All Rights Reserved © Alcatel-Lucent 2008
Mobility
Monitor different kinds of handovers.
Soft handover- defining the right neighbors.
Missing neighbors, New site turn ups
IRAT ( 3G/2G) HO issues.
Check 3G/2G neighbor relations- external cell definition BCCH/BSIC to
match with internal cell values.
Look for issues in the target 2G cell.
Main KPIs: CSV IRAT failure rate, Soft handover success ratio, AMR soft
handover success ratio, PS soft handover success ratio.
- 19. All Rights Reserved © Alcatel-Lucent 2008
Example # 3 ( mobility) CSV IRAT
Cell ( W_DL_Delhi_351_10@) high IRAT HO failure rate
with AMR traffic of 0.25 Erl
Drill down:
Iu release from core.
Preparation failure. Need
to check for resource
issues.
- 20. All Rights Reserved © Alcatel-Lucent 2008
Coverage
Used for monitoring cell interference status and soft handover gain in a
RNC or cluster.
Main KPIs: SHO overhead, UL Interference Cell Ratio
SHO overhead -Used to evaluate the consumption of resources due to
soft handover.
Trade off between resource consumption and soft handover benefits.
UL Interference cell ratio= (No. of cells with mean RTWP -98 dbm/
Total No. of Cells).
RTWP high/ low? Significance??
- 22. All Rights Reserved © Alcatel-Lucent 2008
Service Integrity
Indicates the service capabilities for PS/HSDPA throughput on busy hour
in each cell and for evaluating the UL BLER values for each cell.
Main KPIs:
Average UL Throughput for R99 services.
Average DL Throughput for R99 services.
HSDPA throughput.
HSUPA throughput.
- 24. All Rights Reserved © Alcatel-Lucent 2008
CQI
‡ Channel Quality Index (CQI) is a measure of the quality of DL radio
interface measured at the handset ( between 0 and 30)
‡ The Node B uses this information in the evaluation and assignment of the
downlink air interface throughput for the handset every 2ms, the higher
the reported CQI, the higher the achievable throughput.
‡ CQI is not the only factor in the evaluation, however it is the only factor
that can be readily improved through optimization.
‡ CQI is a function of Ec/No.
- 26. All Rights Reserved © Alcatel-Lucent 2008
Availability
Measures the availability of resources.
Main KPIs: Radio Network Unavailability Ratio, Worst Cell Ratio
Formula:
- 27. All Rights Reserved © Alcatel-Lucent 2008
Traffic
Used to evaluate the circulated traffic such as CS Erlangs, PS Traffic,
Mean UE number for various kind of services.
Key KPIs: No. of CS users, No. of PS R99 users, No. of HSDPA users, No. of
HSUPA users, HSDPA traffic volume, HSUPA traffic volume.
Example:
CS Equivalent Erlang of RNC VS.CSLoad.Erlang.Equiv.RNC:
This KPI provides the equivalent Erlang values of all the services in the CS domain in the RNC
- 28. All Rights Reserved © Alcatel-Lucent 2008
Sample formula
No. of CS users=
(VS.RB.AMR.DL.12.2+VS.RB.AMR.DL.10.2+VS.RB.AMR.DL.7.95+VS.RB.AMR.DL.7.4+VS.RB.AM
R.DL.6.7+VS.RB.AMR.DL.5.9+VS.RB.AMR.DL.5.15+VS.RB.AMR.DL.4.75)
No. of HSDPA users= VS.HSDPA.UE.Mean.Cell,VS.HSDPA.UE.Max.Cell.
HSDPA Traffic volume= VS.HSDPA.MeanChThroughput.TotalBytes
