Document Text Contents
Page 1
UMTS Optimization Guideline Page 1 of 84
UMTS Optimization Guideline
BASIC TUNING ............................................................................................................................................. 2
KPIS AND SERVICE REQUIREMENTS .................................................................................................................... 2
IRAT Performance .................................................................................................................................. 2
CS Performance ...................................................................................................................................... 2
CS Requirements .............................................................................................................................................. 3
PS Performance ...................................................................................................................................... 4
PS Requirements ............................................................................................................................................... 5
TOOLS ............................................................................................................................................................ 8
Tools Requirements ................................................................................................................................ 8
RF Measurements ........................................................................................................................................... 11
Throughput Measurements .............................................................................................................................. 12
Call Performance ............................................................................................................................................ 13
Tools Currently Available to Capture / Process data .......................................................................... 15
Drive Test Equipment and Software ............................................................................................................... 18
Post-Processing Software ................................................................................................................................ 22
PRE-LAUNCH OPTIMIZATION PROCESS ............................................................................................................... 24
Database Verification ........................................................................................................................... 25
Drive Test Route Selection .................................................................................................................... 27
Drive Test Data Collection ................................................................................................................... 29
Data Post-processing and Root-Cause Analysis .................................................................................. 30
Root Cause Analysis and Recommendation ......................................................................................... 31
High Downlink Interference ........................................................................................................................... 31
Pilot Pollution ................................................................................................................................................. 33
Out of Pilot Coverage ..................................................................................................................................... 34
Insufficient received UL DPCH power ........................................................................................................... 34
High UE TX Transmit Power ......................................................................................................................... 35
Swapped feeders ............................................................................................................................................. 36
Low data throughput ....................................................................................................................................... 38
Handover Event Detection Failure .................................................................................................................. 40
No Suitable Cell .............................................................................................................................................. 42
Assessing Success of Recommended Change ....................................................................................... 42
OMC STATISTICS BASED TUNING ....................................................................................................... 43
KPIS ............................................................................................................................................................ 43
IRAT - Inter Radio Access Technology (IRAT) performance .............................................................. 51
CS Performance additional information .............................................................................................. 52
PS Performance additional information ............................................................................................... 52
TOOLS .......................................................................................................................................................... 53
Tools Requirements .............................................................................................................................. 53
Tools Currently Available to Capture / Process Data .......................................................................... 54
POST-LAUNCH OPTIMIZATION PROCESS ............................................................................................................. 57
Data Post-processing and Root-Cause Analysis .................................................................................. 58
Optimization Strategy per Root-cause and/or Problem Category/Type/Area ...................................... 68
Assessing Success of Recommended Change ....................................................................................... 84
inCode CONFIDENTIAL and PROPIETARY
Page 43
UMTS Optimization Guideline Page 43 of 84
Drive test and performance statistics are often used to assess success of
the recommended changes. Drive test conducted in the same problematic
area can verify whether these changes improve the performance in the
problematic area. Performance statistic in the following few days can be
used to check whether there is any side effect to other areas or other
cells.
OMC Statistics Based Tuning
KPIs
Differentiated Performance Monitoring
The QoS of differentiated packet switched (PS) and circuit switched (CS)
services can be assessed through counters collected and classified in the
RNS. The analytical approach assumes that the network topology where
the service performances are analysed is already defined (or selected
within a wider scope) together with the measurement period (history), and
user satisfaction criteria.
The identified area may encompass radio network controllers (RNC), base
stations (BSs) or Node Bs, cells and the interface between the base
station and the radio network controller (Iub). Our target is to define
essential counters and key performance indicators (KPIs) that need to be
retrieved, and/or derived from measurements in NEs, for a capacity and
QoS status view in the RNS and/or a detailed performance analysis. In the
latter case, for example, performance results may be compared directly to
the target values or, since only the QoS perceived by end-user matter,
expressed in terms of satisfied users. The network administrator may then
compare the number of satisfied users to the related target thresholds
defined a priority.
inCode CONFIDENTIAL and PROPIETARY
Page 83
UMTS Optimization Guideline Page 83 of 84
set to 9 for e1a and to 14 for e1a’. The event e1a’ inherits the settings of
event e1a except for the triggering threshold defined as follow:
Re1a’ = Re1a – Roffset, with Re1a’ ≥ 0
Description of the problem
The parameter Roffset was initially set to 0dB such that e1a and e1a’ have
the same triggering threshold.
With this original setting events e1a and e1a’ are sent at the same time
resulting in a release of the radio links in case of SHO addition failure.
Indeed, as the e1a’ is sent to release the call in case of SHO failure.
Therefore, all e1a are pre-empted by e1a’ events.
à This behaviour is suspected to create additional drops.
Implemented modification
The value of Roffset will be set to 3dB thus setting. Indeed, With the new
setting, the event e1a’ is delayed by 3dB compared to e1a which is
equivalent to extra time allowed to perform the HO. Eventually, when the
best SC of the neighbour set reaches the level of the best cell of the active
set within the range of 1dB (Re1a’) then the call is released (for CS only –
for PS there are different procedures).
Expected gains and behaviors
à Reduction of the number of e1a’ and at the same time an increase of
the number of e1a
As the e1a’ is delayed we allow more attempts of e1a and therefore this
number should increase. But we should also decrease the number of e1a’
since there will be fewer situations triggering this event. We will verify that
this delta between these two events does not increase so much that it may
overload the RNC in term of signalling.
à Lower CDR
inCode CONFIDENTIAL and PROPIETARY
Page 84
UMTS Optimization Guideline Page 84 of 84
As the system is more resistant to SHO failures there should be
improvements on the call drop rates.
Assessing Success of Recommended Change
The effect of the recommended changes should be analyzed for its
success. This can be verified through,
• Drive Test – real time throughput performance
• Statistics - KPI improvements against Baseline
• QoS Performance – from Statistics or Protocol Analyzer
inCode CONFIDENTIAL and PROPIETARY
UMTS Optimization Guideline Page 1 of 84
UMTS Optimization Guideline
BASIC TUNING ............................................................................................................................................. 2
KPIS AND SERVICE REQUIREMENTS .................................................................................................................... 2
IRAT Performance .................................................................................................................................. 2
CS Performance ...................................................................................................................................... 2
CS Requirements .............................................................................................................................................. 3
PS Performance ...................................................................................................................................... 4
PS Requirements ............................................................................................................................................... 5
TOOLS ............................................................................................................................................................ 8
Tools Requirements ................................................................................................................................ 8
RF Measurements ........................................................................................................................................... 11
Throughput Measurements .............................................................................................................................. 12
Call Performance ............................................................................................................................................ 13
Tools Currently Available to Capture / Process data .......................................................................... 15
Drive Test Equipment and Software ............................................................................................................... 18
Post-Processing Software ................................................................................................................................ 22
PRE-LAUNCH OPTIMIZATION PROCESS ............................................................................................................... 24
Database Verification ........................................................................................................................... 25
Drive Test Route Selection .................................................................................................................... 27
Drive Test Data Collection ................................................................................................................... 29
Data Post-processing and Root-Cause Analysis .................................................................................. 30
Root Cause Analysis and Recommendation ......................................................................................... 31
High Downlink Interference ........................................................................................................................... 31
Pilot Pollution ................................................................................................................................................. 33
Out of Pilot Coverage ..................................................................................................................................... 34
Insufficient received UL DPCH power ........................................................................................................... 34
High UE TX Transmit Power ......................................................................................................................... 35
Swapped feeders ............................................................................................................................................. 36
Low data throughput ....................................................................................................................................... 38
Handover Event Detection Failure .................................................................................................................. 40
No Suitable Cell .............................................................................................................................................. 42
Assessing Success of Recommended Change ....................................................................................... 42
OMC STATISTICS BASED TUNING ....................................................................................................... 43
KPIS ............................................................................................................................................................ 43
IRAT - Inter Radio Access Technology (IRAT) performance .............................................................. 51
CS Performance additional information .............................................................................................. 52
PS Performance additional information ............................................................................................... 52
TOOLS .......................................................................................................................................................... 53
Tools Requirements .............................................................................................................................. 53
Tools Currently Available to Capture / Process Data .......................................................................... 54
POST-LAUNCH OPTIMIZATION PROCESS ............................................................................................................. 57
Data Post-processing and Root-Cause Analysis .................................................................................. 58
Optimization Strategy per Root-cause and/or Problem Category/Type/Area ...................................... 68
Assessing Success of Recommended Change ....................................................................................... 84
inCode CONFIDENTIAL and PROPIETARY
Page 43
UMTS Optimization Guideline Page 43 of 84
Drive test and performance statistics are often used to assess success of
the recommended changes. Drive test conducted in the same problematic
area can verify whether these changes improve the performance in the
problematic area. Performance statistic in the following few days can be
used to check whether there is any side effect to other areas or other
cells.
OMC Statistics Based Tuning
KPIs
Differentiated Performance Monitoring
The QoS of differentiated packet switched (PS) and circuit switched (CS)
services can be assessed through counters collected and classified in the
RNS. The analytical approach assumes that the network topology where
the service performances are analysed is already defined (or selected
within a wider scope) together with the measurement period (history), and
user satisfaction criteria.
The identified area may encompass radio network controllers (RNC), base
stations (BSs) or Node Bs, cells and the interface between the base
station and the radio network controller (Iub). Our target is to define
essential counters and key performance indicators (KPIs) that need to be
retrieved, and/or derived from measurements in NEs, for a capacity and
QoS status view in the RNS and/or a detailed performance analysis. In the
latter case, for example, performance results may be compared directly to
the target values or, since only the QoS perceived by end-user matter,
expressed in terms of satisfied users. The network administrator may then
compare the number of satisfied users to the related target thresholds
defined a priority.
inCode CONFIDENTIAL and PROPIETARY
Page 83
UMTS Optimization Guideline Page 83 of 84
set to 9 for e1a and to 14 for e1a’. The event e1a’ inherits the settings of
event e1a except for the triggering threshold defined as follow:
Re1a’ = Re1a – Roffset, with Re1a’ ≥ 0
Description of the problem
The parameter Roffset was initially set to 0dB such that e1a and e1a’ have
the same triggering threshold.
With this original setting events e1a and e1a’ are sent at the same time
resulting in a release of the radio links in case of SHO addition failure.
Indeed, as the e1a’ is sent to release the call in case of SHO failure.
Therefore, all e1a are pre-empted by e1a’ events.
à This behaviour is suspected to create additional drops.
Implemented modification
The value of Roffset will be set to 3dB thus setting. Indeed, With the new
setting, the event e1a’ is delayed by 3dB compared to e1a which is
equivalent to extra time allowed to perform the HO. Eventually, when the
best SC of the neighbour set reaches the level of the best cell of the active
set within the range of 1dB (Re1a’) then the call is released (for CS only –
for PS there are different procedures).
Expected gains and behaviors
à Reduction of the number of e1a’ and at the same time an increase of
the number of e1a
As the e1a’ is delayed we allow more attempts of e1a and therefore this
number should increase. But we should also decrease the number of e1a’
since there will be fewer situations triggering this event. We will verify that
this delta between these two events does not increase so much that it may
overload the RNC in term of signalling.
à Lower CDR
inCode CONFIDENTIAL and PROPIETARY
Page 84
UMTS Optimization Guideline Page 84 of 84
As the system is more resistant to SHO failures there should be
improvements on the call drop rates.
Assessing Success of Recommended Change
The effect of the recommended changes should be analyzed for its
success. This can be verified through,
• Drive Test – real time throughput performance
• Statistics - KPI improvements against Baseline
• QoS Performance – from Statistics or Protocol Analyzer
inCode CONFIDENTIAL and PROPIETARY
