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Transcript of Gsm Testaus
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Testing of GSM
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Contents GSM network quality audit
Network quality benchmarking Optimisation
Statistics / Operation & Maintenancemeasurements
Field measurements
GPRS measurements Testing of special features
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GSMRadio Network Quality Audit
and Optimisation
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Background On what basis does the customer rate GSM operators quality ?
_ Prices
_ Coverage area _ Call blocking/dropping_ Speech quality_ Customer service
_ Else?
The user experienced service quality in GSM links directly to theperformance of the radio network
Differentiation from competitors
Radio networkquality related!
Radio networkquality related!
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Network quality benchmarking
How does your networks quality matchagainst the competitors ?
and against the world standard ?
Quality Survey /
Urban area
Call
success
rate
Handover
success
rate
DL
signal
quality
DL signal
power level
MS TX
power class
900
MS TX
power class
1800
Handovers/
call
SQI
MTC 95,70 % 97,90 % 0,4 -67.1 dBm 9,6 5,0 3,6 28,1
Competitor 96,80 % 99,00 % 0,4 -61.6 dBm 5,5 3,5 3,5 28,8
Operator 1 (+1m) 97,90 % 99,20 % 0,2 - 8,7 1,8 2,5 29,1
Operator 2 (+1m) 96,90 % 95,50 % 0,5 - 7,2 1,5 1,4 28,2Operator 3 (< MTC) 95,40 % 96,10 % 0,6 - 7,8 N/A 3,1 27,3
Operator 4 (< MTC) 95,20 % 95,00 % 0,3 - 8,7 N/A 1,7 28,9
Operator 5 (< MTC) 95,20 % 99,10 % 0,5 - 7,3 1,4 2,4 28,8
Examplebenchmarkingstatistics
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Field measurements
Benchmarking Troubleshooting
_ statistics, customer complaints Base station start-up
Testing equipment_ Testing software e.g. TEMS Ericsson in a laptop_ Test mobile phones (one or more)
_ Indoor/outdoor antenna _ Cables + battery chargers
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Field measurements
Testing route_ Roads, train
_ Hot spot, pedestrian_ Urban, suburban, rural
Test setup_ Idle mode_ Continuous call_ Call sequence (90s calls / 15s idle)
Tested frequencies: 900/900E/1800
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Example _ Call Success Rate
93,0 %
94,0 %
95,0 %
96,0 %
97,0 %
98,0 %
99,0 %
Call success rate
GSM1800 large European
GSM900/1800 large
European
GSM900/1800 largeEuropean
GSM900 small Middle East
GSM900 small Middle East
GSM900/1800 large
European
GSM900/1800 large
European
GSM900 very small
European
GSM900 small European
GSM900/1800 very small
Middle East
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Example _ SQI
0
5
10
15
20
25
30
35
SQI (max 30)
GSM1800 large European
GSM900/1800 largeEuropean
GSM900/1800 large
EuropeanGSM900 small Middle East
GSM900 small Middle East
GSM900/1800 largeEuropean
GSM900/1800 large
European
GSM900 very smallEuropean
GSM900 small European
GSM900/1800 very smallMiddle East
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Network quality benchmarking Could there be an indicator that shows your network is
underperforming ?
Independent benchmark needed What kind of action should be taken to improve the
situation ?
Correctly targeted networkoptimisationQuality Survey /Urban area Callsuccess
rate
Handover
success
rate
DL
signal
quality
DL signal
power level
MS TX
power class
900
MS TX
power class
1800
Handovers/
call
SQI
MTC 95,70 % 97,90 % 0,4 -67.1 dBm 9,6 5,0 3,6 28,1
Competitor 96,80 % 99,00 % 0,4 -61.6 dBm 5,5 3,5 3,5 28,8
Operator 1 (+1m) 97,90 % 99,20 % 0,2 - 8,7 1,8 2,5 29,1
Operator 2 (+1m) 96,90 % 95,50 % 0,5 - 7,2 1,5 1,4 28,2
Operator 3 (< MTC) 95,40 % 96,10 % 0,6 - 7,8 N/A 3,1 27,3
Operator 4 (< MTC) 95,20 % 95,00 % 0,3 - 8,7 N/A 1,7 28,9
Operator 5 (< MTC) 95,20 % 99,10 % 0,5 - 7,3 1,4 2,4 28,8
Examplebenchmarkingstatistics
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Network optimisation process
Customer
Feedback
Field measurements
and performance
evaluations
Operation &
Maintenance
Measurements
Postprocessing
INPUTSMANAGEMENT
MARKETING
CUSTOMER
SERVICE
NETWORK
PLANNING
Continuous process!
Benchmarking
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Optimisation targets
Satisfied customers
Maximum utilisationof hardware
Effective andeconomic use
of network !
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Troubleshooting
Handover problems
Quality problems Coverage problems & New site location identification Network layers fine-tuning Capacity problematics LAC optimisation New feature implementation (software and hardware) Micro cells introduction
Indoor coverage fine-tuning BSS parameter fine-tuning
Omniteles engineers are experienced to encountethe major issues effecting the quality of GSM netw
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Dual Band considerationsDual Band Strategy
Spectrum requirements
Network evolution
from traffic hot spots to seamless coverage
900/1800 spectrum for indoor / outdoor,
interference reduction, data
Capacity gain calculations for different scenarios
Planning and Implementation
Planning methods
BSS parameters
Site suitability criteria Sharing of RF components
Planning / measurement tool requirements
Planning and Implementation
Planning methods
BSS parameters
Site suitability criteria Sharing of RF components
Planning / measurement tool requirements
Utilisation Traffic steering between
900/1800 layers
Parameter optimisation Coverage/capacity GPRS strategy
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Interference check perchannel_ Evaluation of the
significance of the residualinterference
_ HO/Cell selection marginshould be included in theanalysis
_ C/Ic (and C/Ia ) statistics perchannel
Interference per network_ On the dominance area_ C/Ic (and C/Ia ) statistics
_ Shows the overallinterference picture
Interference analysis_ Used by turns with the
allocation in order to
validate (and optimize, ifnecessary) the frequency(reuse) plan
Frequency planning & interference analysis
Frequency planning objectives_QoS objectives
_ Overall C/Ic and C/Ia requirements_ Cell-to-cell C/Irequirements
13,1
6,13
5,13
13,8
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nter erence re uct on
means Antenna redirection the most predictable
coverage is in danger
Antenna tilting ideally very useful: steepens
the slope
in practice difficult to predict
should be always measured useful for large clearence
angles
Power reduction UL/DL interference power
balance is lost coverage is lost
not recommended
All interference reduction meansmay generate problems in other
frequencies
Optimising is done frequency by frequency
Reducing interferenceImproves network quality!
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Optimising adjacencies & LAC Missing neighbours very often result in unnecessary
dropped calls and bad quality
Correct neighbour relations can be determined by
analysing measurement results
Unnecessary LAC updatescan easily increase the
singalling load significantl
Increased signallingreduces the room for payloa
Are your adjacenciesand LACs optimised ?
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Example _ BH traffic
20 June: 290 000 subs 17 mErl/subscriberMean holding time ? -> BHCA/subscriber
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Conclusion The GSM network optimisation process consists of
complex technical measurements and analysis Every network is individually planned and thus have
individual problems which decrease the quality Professionally performed optimisation will increase
customer satisfactionGSM
networkindicators ofEuropeanoperator
customer
How to increase the quality and capacitywith minimum investments ?
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How can Omnitele assist you?
Radio network quality auditand optimisation
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How often?How often? Regularly, e.g. once a year
Where?Where? Predefined areas
How?How?
Performing the quality audit
Why?Why? To observe and follow thequality of the network
With measurementsBy comparing
Who?Who? Independent from theoperator and vendor
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Complete analysis of the qualityperceived by subscribers
Location of interference, inadequatesignal strength and quality, congestion
On-the-job training for Operators ownstaff
Proposal for corrective actions in bothshort and long term
Comparison to the competitors and
world class standard
Network quality audit
-- Objectives --
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Network quality audit-- Area definition --
The most important cities, roads, suburbs
Same basic area every time, expanded with
possible new coverage areas
Areas representing different kind of coverage,different subscriber density etc.
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ca. 1/3 of the # of cells in thearea
30 min. of driving for each
covering the whole sub-servicearea
distinction of areas with different
required coverage probabilities following the foreseen traffic
distribution
all HO pairs tested
closing loops & major highways
marketing should be consulted
emphasis on the city
the most important roads the most important suburbs
the areas with foreseendifficulties
Measurement route definition
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In addition to complete quality audit weekly
measurements are recommended
Network quality audit
-- Regularity --
Once a year if the network is quite stable
More often if the network is still under
construction
N k li di
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Network quality audit
--The auditor --Should be independent from the OperatorsTechnical Department and the Vendor
Because, then ...
The comparison will be objective
Should have experience from other networks
The Operator gets the information what is t
performance level of the network comparedthe other networks
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Quality audit-- Comparison --
Comparison with previous quality auditsComparison with competitors
By Quality Index
Predefined criteria the network should fulfill
Quality Index (measured indicators)
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Long and extensive experience on radio network planning_ Dimensioning and nominal planning_ Site planning_ Parameter planning _ Network tuning and optimisation
Experience from several equipment suppliers
Projects:
GSM planning in Finland _ Radiolinja project (worlds first GSM network) _ GSM1800 city networks_ Ongoing Finnish 2G project (3rd Finnish operator)
GSM planning abroad_ Italy Czech republic_ Netherlands Brazil
Why Omnitele ?
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GSM network dimensioning/nominal planning for start-up operators_ Tanzania_ Jordan_ Pakistan
Network audits and optimisation projects_ Finland
Radiolinja City networks
Finnish 2G_ Abroad:
Greece Ivory Coast Kuwait Togo Jersey Czech Republic
Guernsey Faroe Islands Cyprus Andorra Bahrain
Why Omnitele ?
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GPRS Optimisation ingeneral
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Optimisation Process
Input
The business strategy for GPRS
Existing and desired quality of the
network (field measurements & OMC
studies):
Congestion
QoS of the existing network
InterferenceDifferent vendor solutions
Required services and expected
usage
Input
The business strategy for GPRS
Existing and desired quality of the
network (field measurements & OMCstudies):
Congestion
QoS of the existing network
InterferenceDifferent vendor solutions
Required services and expected
usage
Output
Optimal parameter settings:
Dedicated/dynamic radio
capacity allocation
Traffic steering between the
radio layers
Coding scheme adaptation
Different timers
Optimal hardware configurationProtocol optimisation
Key performance indicator
definition and measurements
Future plan winner strategy
Output
Optimal parameter settings:
Dedicated/dynamic radio
capacity allocation
Traffic steering between theradio layers
Coding scheme adaptation
Different timers
Optimal hardware configuration
Protocol optimisation
Key performance indicator
definition and measurements
Future plan winner strategy
Best quality with minimum investment
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Measurement System Set-upEnd-to-End data performance
GPRS layer data performance
RF performance
Data at
application layer
Data at
RLC/LLC layer
Air-interface
Data at
application layer
Data at
RLC/LLC layer
Air-interface
GPRS Mobile Server
End-to-End data performance
GPRS layer data performance
RF performance
Data at
application layer
Data at
RLC/LLC layer
Air-interface
Data at
application layer
Data at
RLC/LLC layer
Air-interface
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Monitored Key Performance Indicators
(KPI) C/I of the measured channels
Average RLC throughput (kbit/s) Average LLC throughput (kbit/s)
Average number of timeslots used by a single user
CS usage (% of time in the CS1/CS2 *)
Average cell reselect time Network response time (RTT)
RLC bit error rate
*) Available only in networks with dynamic CS adaptation
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GPRS Parameter Planning (1) Goals: To handle GPRS in cells with high CS (speech)
traffic To steer the GPRS traffic to wanted cells
Adequate definition of GPRS timers
Radio interface capacity division between CS/PS Optimise the performance of specific service
Optimised end-user experience !
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GPRS Parameter Planning (2) Omnitele has profound hands-on experience with Alcatel GPRS parameters
Ericsson GPRS parameters Nokia GPRS parameters
Daily planning &Optimising
Drive tests
Troubleshooting
Measuring GPRS network performance
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Measuring GPRS network performance
Number of timeslots used permobile
Coding scheme
usage
Data flowbehaviour
Re-
transmissions Cell re-
selections, RA
updates etc.
RLC and LLC
Throughput
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GPRS Networkperformance
benchmarking
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Why benchmark the network
performance ?
Performance of the GPRS networks vary significantly
between the operators
The QoS status of operators GPRS network is best
determined by benchmarking the network performanceagainst competitors performance and/or world class operators
operating in different markets
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Benchmarking Results
Examples
33.331.3
33.231.3
34.7
32.4
15.0
20.0
25.0
30.0
35.0
X Y Z
Throughput DL [kbit/s]
RLC Throughput [kbit/s]
LLC Throughput [kbit/s]
1.5
1.8
1.1
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
X Y Z
Network response time (s)
Network response
time (s)
Example country:
Three nation-wide GPRS operators
Same drive routes in the benchmarking
Significant differences in KPIs of the three operators
I i h P f f
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Improving the Performance of
Your Network
After benchmarking the GPRS performance, theproblem areas will be identified
Recommendations for improvements are given
Service optimisation plan will be made
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How can Omniteleassist you ?
Example of Omnitele s GPRS Projects
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Example of Omnitele s GPRS ProjectsNetwork acceptance and optimisation
1 Int roduc tion
2 Descript ion of field measurements2.1 GPRS measurement model2.1.1 Application layer performance measurements2.1.2 GPRS layer performance measurements2.1.3 RF performance measurements2.2 Monitored Key Performance Indicators2.2.1 Carrier t o Interference rat io for t he measured channels (dB)
2.2.2 Coding scheme usage (%)2.2.3 RLC/LLC throughput (kbit/s)2.2.4 Cell reselection t ime (s)2.2.5 Routing area update time (s)2.2.6 Network response time (s)
3 Findings during the Installat ion3.1 Alcatel acceptance tests
3.1.1 MFS acceptance tests3.1.2 Core acceptance tests3 .2 Detect ed problems3.2.1 MFS3.2.2 Core
4 Integrat ion t est ing4.1 Carrier to Interference rat io4 .2 Coding scheme usage4.3 Throughput4.3.1 Normal cell load t hroughput measurements4.3.2 High cell load throughput measurements4 .4 Cell reselec tion4 .5 rou ting area update time4.6 Network response t ime4.6.1 Pinging with Windows Command prompt4.6.2 Pinging with different int ervals between the pings
5 GPRS Parameter fine-tuning5.1 Further routing area update testing5.2 Optimisation of the coding scheme usage
5.2.1 CS_Lev parameter5.2.2 CS_Qual_1_2 / CS_Qual_2_15.2.3 TBF_CS_Period1 / TBF_CS_Period25.3 Congestion control5.4 network response time optimisation5.5 Other investigated issues5.5.1 Frequency scans in the east coast5.5.2 Missing adjacencies
6 Comparison of finnish GPRS operators networkPerformance indicators6.1 Throughput6.2 Cell Reselection time (s)7 comparison of different vendors GPRS features7.1 Automatic Link adaptation (ALA)7.2 Congestion control7.3 Multiplexing users into the Timeslots7.4 TRX preference
8 suggestions for GPRS network development8.1 Alcatel GPRS core rel2 and BSS software B78.2 Traffic monitoring8.3 Air-Interface compression software9 Conclusion
H C O it l A i t Y ?
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How Can Omnitele Assist You?
Contract negotiations:
Assistance in definition of the technical framework to the systemspecifications: How should the GPRS system perform?
Hands-on experience: Alcatel, Ericsson and Nokia GPRS systems
Implementation:
Verification of the system performance: Specification of the operatoracceptance tests and system integration tests
Parameter planning, parameter fine-tuning and optimisation of the GPRS
network Service optimisation:
WAP&Web: Parameters&timers
Content optimisation: Performance Enhancement Proxy selection process
MMS: Radio capacity optimisation
GPRS performance benchmarking
Comparison of your GPRS networks performance to your competitors
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Please visit our web sitewww.omnitele.fi
for more information