Optimization: Introduction Prepared by Performance Team
Contents
Global indicators
Typical Radio Network Problem
Coverage Problem
Interference problem
Unbalanced power budget problem
Congestion problem
Problems and responsible parties
Optimization: Introduction Prepared by Performance Team
Global Indicators
4 stages of a call establishment, 2
stages (1&2) for location update :
1. Radio link establishment Phase
2. SDCCH Phase
then only “Circuit Switch call”
3. TCH assignment Phase
4. Alerting/Connect Phase
Optimization: Introduction Prepared by Performance Team
Global
Indicators
MS BTS BSC MSC
(RACH)
CHANNEL REQUESTCHANNEL REQUIRED
CHANNEL ACTIVATION (SDCCH)
CHANNEL ACTIVATION ACK
IMMEDIATE ASSIGN COMMEND
(AGCH)
IMMEDIATE ASSIGN
(SDCCH)
SABM (L3 info)
(SDCCH)
UA (L3 info)
ESTABLISH IND (L3 info)CR (Connection Request: L3
INFO)
CC (Connection Complete)
AUTHENTICATION REQUEST
AUTHENTICATION RESPONSE
CIPHERING MODE COMMAND
CIPHERING MODE COMPLETE
SETUP
CALL PROCEEDING
LOCATION UPDATE REQUEST (IN CASE OF LU)
LOCATION UPDATE ACCEPT (IN CASE OF LU)
TMSI REALLOCATION COMPLETE (IN CASE OF LU)
ASSIGNMENT REQUEST
PHYSICAL CONTEXT REQUEST
PHYSICAL CONTEXT CONFIRM
CHANNEL ACTIVATION (TCH) TCH allocation
CHANNEL ALLOCATION ACK.
(SDCCH)
ASSIGNMENT COMMEND
SABM
UA (L3 info)TCHESTABLISH INDICATION
ASSIGNMENT COMPLETE
ASSIGNMENT COMPLETE
ALERTING
CONNECT
CONNECT ACK.
CONVERSATION
Mobile Originated Call (MOC)
1. Radio Link
Establishment Phase
2. SDCCH Phase
3. TCH Assignment Phase
4. Alert and Connect Phase
Optimization: Introduction Prepared by Performance Team
Global Indicators
Handover : Intracell HO MS BTS BSC MSC
Measurement ReportMEASUREMENT RESULT
PHYSICAL CONTEXT REQUEST (old channel)
PHYSICAL CONTEXT CONFIRM (old channel)
CHANNEL ACTIVATION (new channel)
(SDCCH)
SABM (L3 info)
(SDCCH)
UA (L3 info)
ESTABLISH IND (new channel)
CHANNEL ACTIVATION ACK (new channel)
ASSIGNMENT COMMEND (old channel)ASSIGNMENT CMD
ASSIGNMENT CMP ESTABLISH COMPLETE (new channel)
HANDOVER PERFORMED
RF CHANNEL RELEASE (old channel)
RF CHANNEL RELEASE ACK (old channel)
Optimization: Introduction Prepared by Performance Team
Global Indicators
Handover : Internal HO
MSServing
CellBSC MSC
Meas. Report
MEASUREMENT RESULT
HANDOVER COMMAND
HANDOVER ACCESS
CHANNEL ACTIVATION
SABM (L3 info)
UA (L3 info)
HANDOVER PERFORMED
Target
Cell
CHANNEL ACTIVATION ACK.
HO CMD
HANDOVER DETECTION
PHYSICAL INFORMATION
ESTABLISH INDICATION
HANDOVER COMPLETE HO CMP
Optimization: Introduction Prepared by Performance Team
Global Indicators
Handover : External HO MS Serving Cell MSCBSC
MEAS_REPORT
MEAS_RESULT
HO_COMMAND
HO_ACCESS
SABM (L3 info)
UA (L3 info)
Target Cell
HO_REQUIRED
HO_DETECTION
ESTABLISH_INDICATION
HO_COMPLETE
Release of TCH
BSC MS
CR (HO_REQUEST)
CC CHANNEL_ACTIVATION
CHANNEL_ACT_ACK
HO_REQUEST_ACK
(HO_COMMAND)
HO_ACCESS
HO_DETECTION
PHYSICAL_INFO
HO_COMPLETE
CLEAR_COMMANDCause: HO_SUCCESSFUL
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators :
SDCCH Congestion
SDCCH Assignment Failure
SDCCH Drop
TCH Assignment Failure
Call Drop
Call Setup Success
Call Success
Outgoing Handover
Incoming Handover
Handover Causes Distribution (Better/Level/Quality/MCHO/...)
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH Congestion : MS BTS BSC
(RACH)
CHANNEL REQUESTCHANNEL REQUIRED
IMMEDIATE ASSIGN COMMEND
(AGCH)
IMM. ASS. REJECT (OPTION)
NO FREE SDCCH !!!
MS will try to request again for a certain of times
If still failures, it will
Wait for a certain of time without reception of
immediate_assign message
Try an automatic cell_reselection in case of
LU (no impact for subscriber)
Notify a network error for call establishment
(call setup failure for subscriber)
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH Congestion : Main causes
Too much SDCCH “normal” traffic for cell
SDCCH design
Logical cell design, extra TRX, new site
“Common Transport Effect” Difficult to avoid for small cells
LA border at crowded area
Abnormal SDCCH traffic
“phantom” channel requests
Inadequate LAC design, causing too much
LU
Redesign LAC
Problem with neighbor cells belong to other
LAC
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH RF Failure : main causes
Real radio problems
Unbalanced power budget
Bad coverage
Interference
In case of radio failure, MS will retry as in case of
SDCCH congestion
MS BTS BSC MSC
(RACH)
CHANNEL REQUESTCHANNEL REQUIRED
CHANNEL ACTIVATION (SDCCH)
CHANNEL ACTIVATION ACK
IMMEDIATE ASSIGN COMMEND
(AGCH)
IMMEDIATE ASSIGN
??? no message from MS
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH RF Failure : main causes
“Phantom/Ghost/Spurious/Dummy...RACH”
Channel request received but not sent : 3
causes
1. Noise decoding
2. Reception of channel request sent to a
neighbor cell
3. Reception of HO_ACCESS sent to a
neighbor cell
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH RF Failure : main causes : Phantom RACH
1. Noise decoding
GSM 05.05: “0.02% of RACH Frame can be
decoded without error without real input signal” (this extra-load has no impact for the system)
BCCH not combined: 156 phantom
RACCH/hour (or about 0.08 Erlang SDCCH)
BCCH combined: 83 phantom RACH/hour
During period with low real traffic (night), high
rate of phantom RACH
No impact for subscriber
But impact on indicator SDCCH RF access
failure
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH RF Failure : main causes : Phantom RACH
2. Channel request sent to neighbor cell
Subscriber is not impacted ( the real transaction
is performed elsewhere)
But SDCCH RF access failure is impacted
Usual radio planning rules are sufficient to avoid
the trouble (BSIC and BCCH frequency plan)
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH RF Failure : main causes : Phantom RACH
3. Channel request due to handover
During HO, first message sent to target cell is
HO access which is an access burst like
channel_request
If received on BCCH, can be understood as a
channel-request
This case is the most dangerous
MS is sending usually a sequence of HO
Access message, every frame !!
In some cases, this can create phantom RACH
if the frequency of TCH is co- or adjacent to one
of the interfered BCCH
Can block very easily SDCCH
Optimization: Introduction Prepared by Performance Team
Global Indicators
SDCCH Drop :
Loss of connection during SDCCH phase =
SDCCH Drop
3 causes of SDCCH drop
Radio problems when connected on SDCCH
BSS problems (Transcoder and Internal BSS
problems)
Call lost during an SDCCH HO (handover
failure without reversion to old channel)
BTS BSC
CONNECTION FAILURE INDICATION
(cause : radio link failure)
Radio connection loss
CLEAR REQUEST
(cause : radio interface failure)
MSCMS
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH assign failure : Congestion
4 sub causes of congestion
A: Queuing is not allowed
B: Queue is full
C: T11 expired
D: RTCH requests is de-queued due to a
high priority (i.e. emergency call) request to
be queued
BTS BSC
no RTCH available on request cellASSIGNMENT FAILURE
cause No Radio Resources Available
MS
ASSIGNMNET REQUEST
MSC
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH assign failure : Radio
MS BTS BSC MSC
ASSIGNMENT REQUEST
PHYSICAL CONTEXT REQUEST
PHYSICAL CONTEXT CONFIRM
CHANNEL ACTIVATION (TCH) TCH allocation
CHANNEL ALLOCATION ACK.
(SDCCH)
ASSIGNMENT COMMEND
TCHRadio Problem
ASSIGNMENT FAILURE
Radio interface failure
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH assign failure : BSS
MS BTS BSC MSC
ASSIGNMENT REQUEST
PHYSICAL CONTEXT REQUEST
PHYSICAL CONTEXT CONFIRM
CHANNEL ACTIVATION (TCH) TCH allocation
CHANNEL ALLOCATION ACK.
(SDCCH)
ASSIGNMENT COMMEND
BSS Problem
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH Drop : Radio
MS BTS BSC
CONNECTION FAILURE INDICATION
(cause : radio link failure)
Radio Problem
CLEAR REQUEST
(cause : radio interface failure)
MSC
Alerting Connection Phase or Communication : at any time
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH Drop : BSS
Transcoder reported problem
Abis transmission Problem: Microwave,
Microwave antenna, fixed line problems.
Problem on TC boards (hardware problem)
MS BTS BSC
CONNECTION FAILURE INDICATION
(Remote transcoder failure)
Radio Problem
CLEAR REQUEST
(Equipment failure)
MSC
Alerting Connection Phase or Communication : at any time
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH Drop : BSS
Other BSS problem (excluding TC)
Hardware or software failures of BSC/BTS
MS BTS BSC
BSS problemCLEAR REQUEST
O&M intervention
Radio interface failure
MSC
Alerting Connection Phase or Communication : at any time
Optimization: Introduction Prepared by Performance Team
Global Indicators
TCH Drop : Handover
Call drop during handover
MS BTS BSC
HO failure without reversion CLEAR REQUEST
Radio interface message failure
MSC
Alerting Connection Phase or Communication : at any time
Optimization: Introduction Prepared by Performance Team
Global Indicators
Intracell HO Failures
Congestion
Reversion to Old Channel (ROC)
Drop Radio
BSS problem
Optimization: Introduction Prepared by Performance Team
Global Indicators
Intracell HO Failures : Congestion
MSServing
BTSBSC MSC
Measurement ReportMEASUREMENT RESULT
No Free TCH/SDCCH
Intracell HO Failures : Drop
MS BTS BSC MSC
ASSIGNMENT CMDASSIGNMENT COMMAND (old channel)
Release of old and new channels
Optimization: Introduction Prepared by Performance Team
Global Indicators
Intracell HO Failures : Reversion to Old Channel
Serving
BTS
Serving
BSC MSC
SABM (new channel)
UA (new channel)
ESTABLISH IND (new channel)
ASSIGNMENT COMMEND (old channel)ASSIGNMENT CMD
ESTABLISH INDICATION (old channel)
RF CHANNEL RELEASE (old channel)
RF CHANNEL RELEASE ACK (old channel)
MS
XSABM (new channel)
UA (new channel)X
SABM (old channel)
UA (old channel)
ASSIGNMENT FAIL ASSIGNMNENT FAILURE
Optimization: Introduction Prepared by Performance Team
Global Indicators
Internal HO Failures : Reversion to Old Channel
Serving
CellBSC MSC
HANDOVER COMMAND
HANDOVER ACCESS
SABM (L3 info)
UA (L3 info)
Target
Cell
HO CMD
HANDOVER DETECTION
PHYSICAL INFORMATION
ESTABLISH INDICATION
HANDOVER COMPLETE
MS
X
SABM
UM
HO FAILURE
ESTABLISH INDICATION
HO FAILURE
Release of new channel
Optimization: Introduction Prepared by Performance Team
Global Indicators
Internal HO Failures : Drop
MSServing
CellBSC MSC
Meas. Report
MEASUREMENT RESULT
HANDOVER COMMAND
CHANNEL ACTIVATION
Clear_request
Target
Cell
CHANNEL ACTIVATION ACK.
HO CMD
Clear_command
Release of old and new TCH
Optimization: Introduction Prepared by Performance Team
Global Indicators
External HO Failures : Congestion
MS Serving Cell MSCBSC
MEAS_REPORT
MEAS_RESULT
HO_REQUIRED_REJECT
Target Cell
HO_REQUIRED
BSC MS
CR (HO_REQUEST)
HO_FAILURE
Cause: no radio resource available
External HO Failures : A int. Congestion MS Serving Cell MSCBSC
MEAS_REPORT
MEAS_RESULT
HO_REQUIRED_REJECT
Target Cell
HO_REQUIRED
BSC MS
CR (HO_REQUEST)
HO_FAILURE
Cause: terrestrial circuit already allocated
Requested trerestrial resource unavailable
BSS not equipped
Optimization: Introduction Prepared by Performance Team
Global Indicators
External HO Failures : Reversion to Old Channel
MS Serving Cell MSCBSC
MEAS_REPORT
MEAS_RESULT
HO_COMMAND
HO_ACCESS
Target Cell
HO_REQUIRED
Release connection
BSC MS
CR (HO_REQUEST)
CC CHANNEL_ACTIVATION
CHANNEL_ACT_ACK
HO_REQUEST_ACK
(HO_COMMAND)
CLEAR_COMMAND
XHO_ACCESS
XSABM
UAESTABLISH_INDICATION
HO_FAILURE(reversion to pld channel)
Radio interface fail:
Reversion to old channel
Optimization: Introduction Prepared by Performance Team
Global Indicators
External HO Failures : Drop
MS Serving Cell MSCBSC
MEAS_REPORT
MEAS_RESULT
HO_COMMAND
HO_ACCESS
Target Cell
HO_REQUIRED
Release connection
BSC MS
CR (HO_REQUEST)
CC CHANNEL_ACTIVATION
CHANNEL_ACT_ACK
HO_REQUEST_ACK
(HO_COMMAND)
CLEAR_COMMAND
XHO_ACCESS
X
Radio interface fail
SABMX
SABMX
SABMX
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : SDCCH Congestion Rate
Definition: Rate of SDCCH not allocated during radio link establishment procedure due to congestion on Air interface
Comment: Check SDCCH Erlang : if not critical, SDCCH availability/allocation problem, or HO access on a nearby cell side effect or interference on the carrier handling SDCCH (the last 2 can lead to high rate if Phantom RACH
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : SDCCH Assign Failure Rate
Definition: Rate of SDCCH seizure failed (BSS problem, radio access problem) during radio link establishment procedure over the total amount of SDCCH seizure requests during radio link establishment procedure
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : SDCCH Drop Rate
Definition: Rate of dropped SDCCH (SDCCH is established for any transaction OC, TC, LU, ...)
Comment: Drop radio + Drop HO + Drop BSS
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : TCH Assign Failure/Congestion Rate
Definition:
TCH Assign Failure Rate: Rate of RTCH seizure failed (BSS problem, radio access problem) during normal assignment procedure over the total amount or RTCH request for normal assignment procedure
TCH Assign Congestion Rate: Rate of RTCH not allocated during normal assignment due to congestion on Air interface
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : Call Drop Rate
Definition: Rate of dropped calls over the total amount of calls with a successful end
Comment:
Drop BSS + Drop radio + Drop HO
TCH drop occurring after successful assignment but before speech connection are considered as call drop even if from customer’s point of view it is a call setup failure
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : Call Setup Success Rate
Definition: Rate of calls going until TCH successful assignment, that is not interrupted by SDCCH drop neither by assignment failures
Comment:
Subscriber : call not established at the first attempt
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : Call Success Rate (BSS view)
Definition: Rate of calls going until normal release, that is not interrupted by SDCCH drop neither by assignment failures and neither by CALL DROP
Comment:
1 call success =
1 call successfully established
Without any call drop
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : Outgoing Handover Success Rate
Definition: Rate of outgoing external and internal intercell TCH and SDCCH handover successes over the total amount of outgoing external and internal intercell TCH and SDCCH handover required
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : Incoming Handover Success Rate
Definition: Rate of incoming external and internal intercell TCH and SDCCH handover successes over the total amount of outgoing external and internal intercell TCH and SDCCH handover requests
Optimization: Introduction Prepared by Performance Team
Global Indicators Important indicators : Handover Cause Distribution
Definition: Distribution of Handover requests by cause: UL Qual, UL Lev, DL Qual, DL Lev, Better Cell, UL Interference, DL Interference, Interband, Micro cells HO, Concentric cell causes
Optimization: Introduction Prepared by Performance Team
Typical Radio Problems
i. Coverage Problem
ii. Interference problem
iii. Unbalanced power budget
problem
iv. Congestion problem
Optimization: Introduction Prepared by Performance Team
Typical Radio Problems
Several sources of information for
optimization
QoS indicators
Coverage predictions
Customer complaints
Drive tests
Abis/A traces
Other teams information (NSS statistics)
Optimization: Introduction Prepared by Performance Team
i. Coverage Problem
Bad coverage :
A network facing coverage problems has
bad RxLev. RxQual can be bad at the
same time.
Sometimes the RxLev can look OK on the
street (i.e. from drivetest) but coverage
inside the buildings can be poor due to
building losses. Building losses can
range from 10 to 30 dB or more.
Optimization: Introduction Prepared by Performance Team
i. Coverage Problem
Indications : Customers complain about dropped calls
and/or “No Network” OMC QoS indicators
– TCH failure rate
– Call drop rate
– Low proportion of better cell HO
– High rate of DL & UL Level HO (possibly also DL/UL quality HO)
A interface indicators
– High rate of Clear Request message, cause radio interface failure
Drive Test
– Poor RxLev ( < -95 dBm)
Optimization: Introduction Prepared by Performance Team
i. Coverage Problem
Investigation and Optimization : If actual coverage is not the one
predicted by planning tool – Check antenna system (azimuth, crossed
sector?)
– Check prediction in the tool (EIRP, Clutter Type, Obstructing building?). Most of the time the prediction will be incorrect, as it is only a computer simulation
– Increase or decrease antenna down-tilt
– Check BTS output power set in the OMC-R (BS_TXPWR_MAX: should always be set at 0)
Optimization: Introduction Prepared by Performance Team
i. Coverage Problem
Investigation and Optimization :
If actual coverage OK compared to
predicted ones
– Improve coverage by adding Macro site,
Microcell site (Border or Shadow areas), or
IBC site (In-building coverage).
– Use parameter setting ex. Bi-layer
Handover.
Optimization: Introduction Prepared by Performance Team
i. Coverage Problem
Example on thresholds :
From Drive test or Abis Interface
RxLev < -95 dBm
and
RxQual > 4
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Interference :
A network facing interferences
problems presents good RxLev
and bad RxQual in the same
time on some areas.
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Indications : Customers complain about bad speech
quality (noisy calls) and/or call drops
OMC QoS indicators
– SDCCH/TCH Drop
– Low proportion of better cell HO
– High rate of DL/UL quality HO and interference HO
– Low HO success rate
A interface indicators
– High rate of Clear Request message, cause radio interface failure
Drive Test
– RxQual > 4 with RxLev > -85 dBm
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Typical causes :
GSM interferences
Co-channel
adjacent
Non GSM Interference
Other Mobile Network
Other RF sources
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Co-channel interference :
C/I = Carrier-to-interference ratio
+12 dB is taken into account for
Alcatel ( +9 dB according to GSM
standard) (i.e. interference can be
9 12 dB weaker than serving
cell to cause poor RxQual).
Level
Frequencyf(cell1)=f(cell2)
+12 dB
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Co-channel interference :
Indications
Downlink and/or Uplink Interference
High rate of quality handover, call drop, and
call setup failure
Investigation
Drive test analysis
Lumpini: Co-channel checking
Check prediction to verify which cell could be
causing the interference
Frequency plan C/I < 12 dB
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Co-channel interference :
Optimization
Antenna optimization
Change frequency
Reduce BTS power (not an option in TA
Orange network)
Concentric cell
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Co-channel interference: Optimization: Concentric cell Concept
Conclusion from Alcatel trial on
Orange’s network (Suburban area)
Concentric cell is difficult to optimize, and hence is rarely used in the network today.
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Adjacent channel interference : C/A = Carrier-to-adjacent ratio
-6 dB is taken into account for Alcatel ( -9 dB according to GSM standard). Level
Frequencyf(cell2)=f(cell1)+1
-6 dB
f(cell1) f(cell2)
E.g.
f(cell1)= Ch.573
f(cell2)= Ch.574
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Adjacent channel interference :
Indications
Downlink and/or Uplink Interference
High rate of quality handover, call drop, and call
failure
Investigation
Adjacent HO statistics (if they are defined as
neighbors). If they often handover, then adjacent
channel interference could be a problem.
Drive test analysis
Lumpini: Adjacent channel checking
Cell coverage prediction
Frequency plan C/I < -6 dB
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Adjacent channel interference :
Optimization
Antenna optimization
Change frequency
Reduce BTS power (not an option in TA
Orange network)
Concentric cell
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem Interference : Forced Directed Retry
MS should connect to Cell_A, but no
TCH available.
MS connects to Cell_B with forced
directed retry
MS is emitting at high level (due to long
distance from Cell_B)
UL interference for Cell_C
Cell_B is emitting at high level (if DL PC
is being used)
DL interference at Cell_C
MS is serving on the 2nd or 3rd best
server: increases chances of
interference problem (poor C/I & C/A as “C” is lower)
Cell_B: Ch.573
Cell_C: Ch.572
Cell_A: Ch.569
Optimization: Introduction Prepared by Performance Team
ii. Interference Problem
Non GSM interference :
Other mobile network Inter-modulation with GSM BTS/MS receiver
Other RF interferers Radar
Shop anti-theft mechanism
Medical devices
Other man-made radio transmission
Illegal usage of GSM frequencies (e.g. illegal imported devices, illegal usage of other organization, ...)
...
Optimization: Introduction Prepared by Performance Team
iii. Unbalance power budget Problem
A cell facing unbalanced power budget problems presents a too high path-loss difference between UL and DL (often DL>UL)
Lower Rx diversity gain of cross polarized antenna in rural area compared to dense area
Crossed feeders
Traffic not directly in boresight of antenna, where cross-polar discrimination is lower
Loose connectors
Faulty antenna, feeder, TMA
Rule : try to have delta as small as possible to avoid access network possible only in 1 direction (usually BTS->MS : OK and MS->BTS : NOK), i.e. uplink limited
Optimization: Introduction Prepared by Performance Team
Indicators : OMC QoS indicators
– High ratio of Uplink level Handover cause
– Low incoming HO success rate
– DL level looks OK for HO, but UL is too weak when HO is attempted
– Degradation of TCH failures and OC call drop indicators
A interface indicators
– High rate of Clear Request message, cause radio interface failure
O&M Alarms
– Voltage Standing Wave Ratio (VSWR)
– TMA
iii. Unbalance power budget Problem
Optimization: Introduction Prepared by Performance Team
Investigation : Abis monitoring:
– ABS(delta Path loss) > 10
» Check if problem is occurring for 1 TRX or all.
– ABS(delta path loss) = ABS(UL Path loss – DL Path loss)
– UL Path loss = MS transmitted power – measured received UL level
– DL Path loss = BTS transmitted power – combiner loss – measured received DL level
– Large difference between uplink and downlink level triggered HO.
Use PM observation counter (in OMC-R)
– RT11
iii. Unbalance power budget Problem
Optimization: Introduction Prepared by Performance Team
Optimization : This equipment
should be checked
TRX types (MP, HP)
Antennas or common RF components,
TMA (common to all TRX of the BTS)
TRX RF cables, LNA
iii. Unbalance power budget Problem
Optimization: Introduction Prepared by Performance Team
iv. TCH congestion Problem
TCH Congestion :
TCH Congestion rate (TCH Assignment Phase) is too high (more than 2%)
Rule : try to meet the offered traffic (asked by users) by providing the right number of resources (TRX extension)
Optimization: Introduction Prepared by Performance Team
iv. TCH congestion Problem
Indications : Customers complain about “Network busy” OMC QoS indicators
– High “TCH Congestion rate”, “RTCH Assignment fail-Congestion”
– Low “incoming Intra/Inter BSC HO success rate” (no TCH available)
– High “Directed Retry rate or Congestion Relief (Motorola)” if activated
A interface indicators: “BSS Congestion failure in OC” – High rate of Assignment Failure message,
No radio resource available
Drive Test
– Handover to better cell is slow, or never occurs
Optimization: Introduction Prepared by Performance Team
iv. TCH congestion Problem
Optimization :
Special events :
– Foreseeable: football match, important meeting, Exhibition, etc.
» Add some extra TRXs
» Add special mobile BTSs (Cell on Wheel)
» Activate HR (may not always be possible due to BSC capacity limitations)
– Not foreseeable: car crash on the highway
Optimization: Introduction Prepared by Performance Team
iv. TCH congestion Problem
Optimization :
Daily periodic problems : At busy hour:
– Hardware solution :
» Add TRX(s)
» Concentric cell
» New site
» Optimize cell boundaries (i.e.
antenna optimization) to share
traffic with surrounding cells
Optimization: Introduction Prepared by Performance Team
iv. TCH congestion Problem
Optimization :
Daily periodic problems : At busy hour:
– Software solution :
» Directed Retry
» Traffic Handover
» Half Rate (Alcatel)
» Congestion Relief (Motorola)
» Flow control (Motorola)
Optimization: Introduction Prepared by Performance Team
Problems and responsible parties
Coverage problem :
If the measured RxLev does not
match the prediction
– Check the prediction, check panoramic
pictures for obstructions
– Field Operation team to check physical
configuration (tilt, azimuth, antenna
height...). Also check for faults in the
antenna system (VSWR, sweep
antennas, DTF test, etc.)
– If Field Operation find no problem,
antenna optimization may be required
(if necessary)
Optimization: Introduction Prepared by Performance Team
Problems and responsible parties
Coverage problem :
If the field reality match the
prediction
– RF team to add new sites (tri-sector,
micro cellular, indoor cells) to improve
poor/no coverage area (Optimizer
requests for some new sites to RF
team regarding to the drive test result)
Optimization: Introduction Prepared by Performance Team
Interference problem :
Optimization team to identify the
interference source and request Spectrum
Management team to correct it in case of
internal source (new frequency planning...)
Unbalanced power budget problem :
Field Operation team to check the impacted
BTS (Antenna, TMA, RF cables, LNA,
diversity system...) according to request
from Optimizer.
Problems and responsible parties
Optimization: Introduction Prepared by Performance Team
TCH Congestion problem :
Regional RF to request TRX
expansion.
Problems and responsible parties
Optimization: Introduction Prepared by Performance Team
Organization
Alcatel KPIs
Optimization Workflow
Optimization Process
Optimization Tools
Report Links
Optimization: Contents
Optimization: Introduction Prepared by Performance Team
Initial First Last Initial First Last
50 Mr. Xavier Lepez ANTE & Performance Mgr. 2912 4995 09-100-6680
51 Ms. Sanida Sengyai น.ส. สนดิา เส็งใย Administrator 0723 5174 0 9100 6677
52 Mr. Rob Werner Engineering Mgr. 1086 5152 0 9100 6466
2EN1110 53 Mr. Andrew Barton Motorola Interface 0570 5151 0 9100 6424
54 Vacant BKK RF Interface
55 Mr. Prasong Kullama นาย ประสงค์ กุลมา Alcatel Interface 0058 4986 0 9100 6432
56 Mr. Ferri Tafreshi Spectrum Management 0991 5150 0 9100 6426
57 Mr. Aekkorn Poomseetana นาย เอกกร ภมูสิธีนา Spectrum Eng. 0239 5149 0 9100 6427
58 Ms. Lilly Sarujikumjornwatana น.ส. ลลิลี่ สรุจกิ าจรวฒันะ Spectrum Eng. 4022 5093 0 6501 0054
59 Vacant Spectrum Eng.
60 Vacant Spectrum Eng.
61 Vacant Spectrum Eng.
62 Mr. Nazli Abdullah Technical Support Mgr. 0609 5153 0 9100 6423
63 Ms. Aphiwan Malaithong น.ส. อภวิรรณ มา้ลายทอง Software Eng. 1846 5143 0 9100 6428
64 Mr. Pnot Limpiphiphatn นาย ปณต ลมิปิพพัิฒน์ Software Eng. 3028 5219 0 9100 6209
65 Vacant Software Eng.
66 Ms. Vorrachitt Veerachitt น.ส. วรจติต์ วรีะจติต์ Frequency Planner (Contractor) - 4027 0 6622 2907
67 Mr. Warakorn Angkaphaiboonsakul นาย วรากร อังคไพบลูย์สกุล Frequency Planner (Contractor) - 4025 0 1833 4452
68 Mr. Sirasith Phanupornprapong นาย ศริสทิธิ ์ ภานุพรประพงศ์ Frequency Planner (Contractor) - 4026 0 1802 2114
69 Mr. Stephane Tella Performance Mgr. - 5111 0 9100 6262
70 Mr. Michael Powell Optimization Mgr. BKK 1045 5189 0 9100 6681
71 Mr. Atinan Tumsatan นาย อาทนัินทน์ ทมุสทา้น Optimization Eng. BKK 1872 4981 0 9100 6684
2EN1110 72 Ms. Thitinun Limpaphinun น.ส. ฐตินัินท์ ลมิปาภนัินท์ Optimization Eng. BKK 2448 4983 0 9100 6691
73 Mr. Supakorn Chumnongrark นาย สภุกร จ านงครั์กษ์ Optimization Eng. BKK 0437 4985 0 9100 6682
74 Ms. Sutthida Dullaya - anukit น.ส. สทุธดิา ดลุยอนุกจิ Optimization Eng. BKK 2244 4984 0 9100 6685
75 Mr. Phairoj Thamrongthanyawong นาย ไพโรจน์ ธ ารงธัญวงศ์ Optimization Eng. BKK 4005 5196 0 6502 0053
76 Mr. Boonyarith Saovapakiran นาย บญุฤทธิ์ เสาวภาคย์หรัิณย์ Optimization Eng. BKK 4006 5027 0 6502 0052
77 Vacant Optimization Eng. BKK
78 Vacant Optimization Eng. BKK
79 Vacant Optimization Eng. BKK
80 Vacant Optimization Eng. BKK
81 Vacant Optimization Eng. BKK
82 Mr. Pongpunt Thanddokmai นาย พงษ์พันธ์ ทัดดอกไม ้ Drive Test Technician 2235 5178 0 9100 6686
83 Mr. Somyos Tharalerd นาย สมยศ ธาระเลศิ Drive Test Technician 2388 5178 0 9100 6688
84 Mr. Prasit Jeayang นาย ประสทิธิ์ เจะ๊หยาง Drive Test Technician 2445 5177 0 9100 6689
85 Mr. Nikhom Lertwilai นาย นคิม เลศิวลิัย Drive Test Technician 2490 5177 0 9100 6690
86 Mr. Laurent Hemonet Optimization Mgr Alcatel 3655 5028 0 9100 6694
87 Mr. Kachaprid Booramyakorn นาย คชาพฤทธิ์ บรัุมยากร Optimization Eng. Alcatel 2533 5173 0 9100 6692
88 Mr. Sarasit Wichaikhtkha นาย สารสทิธิ์ วชิยัขัทคะ Optimization Eng. Alcatel 2376 5177 0 9100 6687
89 Vacant Optimization Eng. Alcatel
90 Vacant Optimization Eng. Alcatel
91 Vacant Optimization Eng. Alcatel
92 Ms. Linda Renou Optimization Mgr Motorola - 5064 0 9100 6696
93 Mr. Wasan Taweesin นาย วสันต์ ทวสีนิ Optimization Eng. Motorola 0715 4982 0 9100 6683
94 Mr. Santiphap Utta นาย สันตภิาพ อุทธา Optimization Eng. Motorola 3483 5021 0 9100 6693
2EN1110 95 Ms. Suratsawadee Kongsettakhonchai น.ส. สรัุสวดี คงเศรษฐกรชยั Optimization Eng. Motorola 3737 5186 0 9100 6695
96 Vacant Optimization Eng. Motorola
97 Vacant Optimization Eng. Motorola
98 Mr. Renaud Lelong BSS Eng. 3658 5144 0 9100 6555
99 Mr. Kittisak Kiatmonkong นาย กติตศิักดิ์ เกยีรตมิั่นคง BSS Eng. 3972 5156 0 6502 0051
100 Vacant BSS Eng.
Ext.Orange
MobileID No.No.
Name In English Name in ThaiPosition
Access Eng
&
Performance
Access Eng
&
Performance
Access Eng
&
Performance
Div/Dept
Optimization: Organization
Optimization: Introduction Prepared by Performance Team
INDICATORSOBJECTIVE FAT
and Phase 2
RXQUAL
90 % of call
samples below or
equal to RXQUAL 3
CSSR >= 98%
TCH Blocking
Rate<= 2 %
SDCCH
Blocking Rate<= 1 %
TCH Drop Rate <= 2 %
HOSR >= 95%
Measured at
OMCR
(Statistical BSS
Quality of Service
Indicators)
<= 2 %
<= 1 %
<= 3%
>= 94%
Drive test for
Quality of Service
indicators
CSSR >= 98 % >= 96 %
85 % of call
samples below or
equal to RXQUAL 3
TYPE OF MEASUREOBJECTIVE PAT
Phase 1A and 1B
Drive test for radio
coverage.
Down
link “RXLEV”See next page.
Alcatel KPIs : Network Statistics
Optimization: Introduction Prepared by Performance Team
Service Area
% of Samples above
or equal to
threshold ("Valid
Measurement Sample
Percentage")
Minimum Radio
Coverage Field
Strength Acceptance
Threshold on Street
Level
Dense Urban 98% - 75 dBm
Urban 96% - 82 dBm
Suburban 93% - 87 dBm
Rural 93% - 97 dBm
Highways 93% - 87 dBm
Alcatel KPIs : Drivetest Statistics
Optimization: Introduction Prepared by Performance Team
Optimization : Workflow
Check Data
Alerts
Trouble Ticket (TT)
Weekly Dashboard
BGW Lists
CAT Status
Daily Dashboard
Worst Cell Lists
Prioritization List
Check Frequency
Check Neighbors
Check Parameters
Neighbors Analysis
The following are activities of one Radio Network
Optimization Engineer (RNOE) managing the areas
Optimization: Introduction Prepared by Performance Team
Optimization : Workflow
Neighbors for new sites
Traffic Study Analysis
Antenna Optimization
Drive Test Analysis &
Problem Log (Potatoes)
Drive Test Reports
CAT Drive Tests
CAT Reports
A/Abis Trace Analysis
Customer Complaints
Meeting
Special Studies and
Requests
Documentation
The following activities are not weekly activities
Optimization: Introduction Prepared by Performance Team
Optimization : Process
Optimization Tasks
Cell-by-cell parameter change/Massive parameter change
Neighbor addition/deletion
Correction Tasks
Cell-by-cell parameter change/Massive parameter change
Neighbor addition/deletion
Spectrum Management Tasks
Frequency change request
Retune request
The following are processes based on Remedy
Optimization: Introduction Prepared by Performance Team
Optimization : Tools
RNO : Radio Network
Optimization tool
(A956)
Drive Test Tools
TEMS
GREYSON
ACTIX (post process
tool)
MapInfo
Lunpini
Nbclient
The following are some tools used by an Optimizer
OMC-R : Operation and Maintenance Center-Radio
NPA : Network Performance Analyzer (A985)
INMS
ASSET
Net Monitor