© omnitele ltd. 2005 1 umts quality of service enabling new mobile applications canto st. kitts...

© Omnitele Ltd. 2005 1

UMTS Quality of Service enabling new mobile

applications

CANTO

St. Kitts & Nevis, 19th – 22nd June 2005

Heidi Lagerström, [email protected]


Agenda

1. Introduction to UMTS• New services

2. Quality of Service (QoS) in UMTS network• Using QoS to improve service quality

3. Service quality measurements in UMTS network• Different ways to measure service quality• Defining correct Key Performance Indicators (KPIs)

4. Conclusions


New generation of mobile networks UMTS

• New data services are driving up traffic in mobile networks

• ARPU generated by data users is rising

• Rise in traffic will bring challenges in maintaining acceptable quality of service

• Service quality is closely tired to new service acceptance

Need to build more network capacity!

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Ma

xim

um

Da

ta R

ate

(k

bp

s)

GSM GPRS EDGE UMTS

Data Rates


Introducing new services

GSM GPRS EDGE UMTS HSDPA

Voice & SMS

MMS picture/videoxHTML browsing

Application downloadingE-mail

Presence/location

WEB browsingCorporate data accessStreaming audio/video

Video sharingVideo telephony

Real-time IPMultimedia and games

Broadband in wide

area

A number of mobile services are bearer

independent in nature

3G-specific services take advantage of higher

bandwidth and real-time QoS

Improved performance, decreasing cost of delivery

Higher bit rates


Agenda




4. Conclusions


Why do we need QoS?

• UMTS networks support services with very different performance requirements

– Real-time services require performance guarantees

– Customer acceptance closely tied to service quality

• Optimal usage of network resources

– Radio resources scarce

– Cost-effectiveness

– Return of investment

• Service and user differentiation

– Meet different needs of customers (e.g. business vs. consumer)

– Support different services (real-time vs. best effort)

• Competitive advantage!

Delay Jitter Loss

Video call High High High Med

Streaming High Med Med Med

Web browsing Med Med Low High

E-mail Low Low Low High

Application BandwidthSensitivity

Performance Requirements


QoS Traffic Classes

Traffic class Characteristics Example application

Conversational Preserve time relation between information entities of the stream. Conversational pattern (stringent and low delay)

Speech

Video calls

Streaming Preserve time relation between information entities of the stream.

Real-time streaming video

Interactive Request-response pattern. Preserve payload content.

Web browsing

Background Destination is not expecting the data within a certain time. Preserve payload content.

E-mail

File downloading

Demanding• Delay• Jitter

Demanding• Bit rate• Jitter

Tolerant• Delay and bit rate

can vary• Integrity

Easiest• Delay and bit rate

can vary• Integrity


QoS Profile Attributes

R99 QoS attribute Example valueResidual BER 10 –5

SDU error ratio 10 –4

Delivery of erraneous SDUs No

Maximum SDU size (octets) 1500

Delivery order No

Transfer delay 100 ms (conversational)

280 ms (streaming)

ARP 1, 2 or 3

Traffic Class Conversational, streaming, interactive, background

THP 1, 2 or 3 (same as ARP)

Maximum allowed bit rate e.g. 64, 128 or 384 kbps

Maximum guaranteed bit rate e.g. 64, 128 or 384 kbps

Depends on operator’s

QoS strategy

Depends on the QoS strategy

and UE/RNC capabilities


QoS Differentiation

Conversational RAB

Streaming RAB

Interactive RAB, THP/ARP = 1


Background RAB

MMS

Web browsing

Push-to-talk

Streaming

Videotelephony

• Each service gets the treatment it requires according to the QoS profile• Network resources are shared according to the service needs• Network resources can be used more efficiently


Operators’ QoS Strategy

Conversational RAB

Streaming RAB



Background RAB

RNC3G

GGSN3G

SGSN

Applicationserver

Node B

HLR

User profiles are stored in HLR.Each user can have several user

profiles, which correspond to different services and are mapped

to different bearers according to the operator’s strategy.

• Operators can practise user differentiation by giving each user set of QoS profiles, which he/she is entitled to use• Operators can practise service differentiation by mapping each service to the bearer that meets its requirements

• Meet the needs of different customers• Offer each service the quality it requires• Optimise network resource usage


Agenda




4. Conclusions


Measuring network performance

RNC3G

GGSN3G

SGSN

Applicationserver

Node B

UTRAN Core nw External nw

E2E service quality,

QoE

Performance statistics from

application serverNetwork statistics from different counters and interfaces

Customerfeedback

Network Performance Monitoring Optimisation


RNC3G GGSN

3GSGSN

Applicationserver

Node B

UTRAN Core nw External nw

Drive tests• Coverage• Service availability• Mobility

Walk tests• Service availability(e.g. city center)• Mobility (low speed)

Benchmarking• Comparative data• Competitor evaluation

End-to-end field measurements

Hot spot tests• Service performance• Indoor coverage• Congested places(e.g. railway stations, shopping malls)


Defining the right KPIs

• Different services have different quality requirements– KPIs must be defined separately for each of the key services

• KPI categories– Service Accessibility– Service Integrity– Service Retainability

• With inadequate performance indicators and monitoring– Hidden problems in network performance and user perceived

quality of service– Poorly defined indicators may show better quality than in the reality

• Incorrect formulas and counters• Unreasonable measurement periods

(too much averaging etc.)


Example: Voice Services - CS

Customer demand

Indicator Measure

Service accessability

Availability & Coverage

Blocked calls

Call setup delay

Ec/No, RSCP

Admission control

RAB assignment

Service integrity Voice quality Noisy frames (FER), MOS

Service retainability

Dropped calls Handover failure

No coverage

Interference


Example: Data Services - PS

Customer demand Indicators Measures

Service accessability

Availability & Coverage

Blocked service access

Service access delay

Ec/No, RSCP

Admission control

Attach, PDP context activation, IP service setup

Service integrity Video quality

Audio quality

Web page download time

E-mail sending time, etc.

BLER, FER, throughput, delay, jitter

Service retainability

Dropped data connection

Connection timeouts

Dropped PDP context/attach

No coverage

Handover failure


WCDMA vs GSM field measurements

GSM WCDMA• BCCH carrier CPICH• TCH DCH• PDCH DCH, Common RACH/FACH• RXLev RSCP• C/I on BCCH CPICH Ec/No• RXQual/ BER DCH BLER• MS TX power UE TX power• HO success SHO/HHO division, ISHO

IFHO success, CM usage• Throughput (GPRS)Throughput per RAB


Example: CPICH coverage – Ec/No

According to Ec/No values both operators have good coverage. Couple of RED areas, which need to be

further investigated!

Operator 1

Operator 2

If large interference areas are generated, the problem could be minimised later by adjusting the

antenna direction or height, or by down tilting the antenna or by slightly tuning the pilot power

levels.


Agenda




4. Conclusions


Conclusions

• UMTS networks bring more capacity to GSM/GPRS mobile networks– Enables operators to launch new services– Increases the ARPU generated by subscribers– Offers better service quality

• In 3G networks QoS management is required– Real-time services require QoS guarantees– Need to support different kinds of services– With QoS mechanisms operators can use their network resources

more efficiently and gain competitive advantage

• To maintain and improve the network performance and user experienced service quality constant monitoring and performance follow-up is needed– Successful network measurements are based on correct KPI

definitions– A combination of end-to-end field measurements, interface probes,

network element counter statistics and customer feedback is required

© Omnitele Ltd. 2004 21© Omnitele Ltd. 2005 21

For more information about Omnitele,please visit our web site

www.omnitele.fi


How can Omnitele help you?

• Network acceptance testing• Network parameter planning• Network audits for GSM/GPRS/EDGE and UMTS

networks– KPI analysis– Drive tests– Hot spot tests– Benchmarks

• Network counter analysis• Network optimisation

© omnitele ltd. 2005 1 umts quality of service enabling new mobile applications canto st. kitts...

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