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End-user QoSWhat, why and how3G optimization
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End-user QoSWhat, why and how
Dr. Henrik Christiansen, CTO
CommWyse A/S, Denmark
3G optimization – Rome – March 28th – March 30th, 2006
Motivation
• Data services – new opportunities• Everybody wants optimum QoE
• What is QoE?• How to measure QoE?• What to do?
• 3G threats• Competing technologies -Wimax, WLAN, EDGE
• Services must work from day one• What tools do operators need?
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A quick test
• Can you answer these questions?• What will be the impact on existing
services when:• Traffic increases?• A new service is added?• The QoS configuration is changed?
• … and how will that impact your business?
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Presentation overview
• The main challenge• Application level QoS
• What it is• How to measure it
• Use of simulation• Case studies• Summary and conclusions
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The main challenge
• Planning• Meet requirements: cost, coverage,
quality, capacity• Coverage / capacity interlinked
• Multiple services and QoS• Planning per service• Variable bit rates • Multiple QoS classes
Cost
Coverage
Quality
Capacity
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Main challenge:Planning a multi-service, multi-datarate network
Application level QoS - QoE
• Quality of experience• Users’ point of view: experienced QoS• Operator’s point of view: technology - KPIs
• This is what your customers see• QoSEE – end-to-end / end-user experienced• Subjective
• Interesting for a group of users• Not interesting for a single test user• Average user / average commuter / average teenager• 90 % fractile
Mismatch
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End-to-end
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RA
NA
P
RA
NA
P
What impacts QoE ?
• The user(s)• Handset• Protocol settings• Device configs• Network dimensioning• Application usage
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Application differences
• Request / response pattern• Protocol overhead• Chattiness• Message sizes• Inter request times
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QoE depends on the application:Application type and usage must be taken into account
Optimizing QoE
• Optimize what?• Optimum QoE means
• Happier users?• More revenue?• Better KPIs?• More customers?
• The big question is: How to measure application level QoS
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A holistic view on networks
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Be proactive!Let QoS drive planning & optimization efforts
Discrete event simulation
• Represents everything that happens to a packet as one event – skips periods where nothing happens
• Simulation approach• Set goal – must be specific• Set up scenario• Run simulation(s)• Analyze / interpret results• Reiterate if goal is not reached
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Case studies
• A QoE view on networks by using advanced protocol simulation
• What is the impact of adding streaming users?
• Specific goal: how many streaming users can be added if the response time for 90% of a group of web browsing business users may not increase by more than 20%?
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Adding a new service- impact on existing services
0
0 . 1
0 . 2
0 . 3
0 . 4
0 . 5
0 . 6
0 . 7
0 . 8
0 . 9
1
0 5 1 0 1 5 2 0 2 5
With existing services onlyAfter deploying new service
CDF of service response times
QoE driven planning
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0
0,5
1
1,5
2
2,5
3
3,5
2 3 4 5 6Number of streaming users addded
Response time (seconds)
90 % of selected group
80 % of selected group
20 %
UMTS
• QoS enabled• Service classes• Prioritization• Packet scheduling• RRM algorithms
• Other• Soft handover• Radio planning• Need for isolation between cells
These handles must be set correctly in order for the services to work as expected
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Analysing QoS
• Multi service networks• QoS goal: preferential treatment of some services• Multiple service classes
• with / without delay guarantees• Optimizing QoE
• Improvement of service• Deterioration of other services
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QoS differentiation
Web service
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1 2 3 4 5 6
E-mail service
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 1 2 3 4 5 6
CDF of service response times CDF of service response times
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All services in same classWeb higher priority than e-mail
Impact of traffic growth
00,10,20,30,40,50,60,70,80,9
1
0 5 10 15 20 25
light loadmedium loadheavy load
CDF of service response times
QoE target
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Use QoE as the optimization target
• QoE is complex• Measurements and network counters tell you
about today and yesterday – but what about tomorrow?
• QoE can be easily predicted by using simulation
• QoE impacts your users…and your business
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Conclusions
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• QoSEE for the typical user is important• A holistic view is required
• A suite of tools – one view each• Combined they provide the full view• Different parts of the organization – one view each• United they provide the full view
• Simulation• can predict QoSEE• is reproducible• delivers a controlled environment• Is the missing link between network parameters
and end-to-end QoS• Is one of the required tools to give the holistic view
Thanks!
• Visit our booth during the conference• Visit: www.commwyse.com – anytime!
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