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World Class Standards

KPIs for Mobile Services

MTSI - Multimedia Telephony Services over IMS

STQ Mobile represented byK. Adler, J. Gustafsson, G. Heikkilä

© ETSI 2007. All rights reserved

Effects of Transmission Performance on Multimedia QoS


Presentation Content

� Introduction� Key Performance Areas� Control Plane� Realtime User Plane

Multimedia Telephony Services over IMS 2

� Realtime User Plane� Non-realtime User Plane� MTSI vs. PoC� Summary


MTSI Interoperability Concept

A B

Voice + SMS + (MMS)

Today Multimedia Telephony

A B

Voice + Video + Messaging+ File sharing+ Presence


A B

C DVoice

Voice

A B

C D

+ Presence


MTSI Communication

My devices My Contacts

+

Communication

+Video Call

Voice Call


+ +

Video share

Chatting

Share a file

Conference call


Add/drop of Media During a Session Users

3


Media

Presence Messaging Voice Video File sharing

1

2


Key Performance Areas

MTSI Control Plane (SIP/SDP)

RegistrationSession setup

Session add/dropSession completion


Session completion

MTSI User Plane(realtime RTP/UDP)

Speech qualitySpeech delayVideo qualityVideo delay

Real-time text

MTSI User Plane(non-realtime MSRP/TCP)

MessagingFile or media sharing


SIP Call Setup and RTP/MSRP Media Flow

Visitednetwork

Homenetwork

SIP SIP

SIP

SIP

TAS


UE A

P.CSCF

S.CSCFHSS I.CSCF

P.CSCF

UE B

SIP

SIP

SIP SIP

SIP

SIP

SIP

RTP or MSRP

I.CSCF


Control Plane KPIs

� MTSI Registration Failure Ratio� MTSI Registration Time

� MTSI Session Set-up Failure Ratio� MTSI Session Set-up Time

Examples onfollowing slides


� MTSI Session Add Failure Ratio� MTSI Session Add Time

� MTSI Session Remove Failure Ratio� MTSI Session Remove Time

� MTSI Session Completion Failure Ratio


MTSI Registration Time

Note that first response is always an authentication failure


MTSIRegistration

Time

authentication failure


MTSI Session Add Time

Terminal IMS Core MTAS

SIP INVITE SIP INVITESIP INVITE to terminating network

SIP 183 Session Progress from terminating networkSIP 183 Session ProgressSIP 183 Session Progress

SIP PRACKResource Reservation

SIP PRACKSIP PRACK to terminating network

IMS Client

User modifies session Initate session signal

User decides to add video

Add time can differ depending on added service, due to


ReservationSIP 200 OK (PRACK)SIP 200 OK (PRACK)

SIP 200 OK (PRACK)

SIP UPDATE SIP UPDATESIP UPDATE to terminating network

SIP 200 OK (UPDATE)SIP 200 OK (UPDATE)SIP 200 OK (UPDATE)

SIP 200 OK (INVITE) SIP 200 OK (INVITE) SIP 200 OK (INVITE)

SIP 180 Ringing SIP 180 Ringing

SIP 180 Ringing from terminating networkCallee alerted

notification

Session changed notification

Alerted signalSession set-up signal

MTSI Add Time

Note that auto-answer is always used for drive-testing

measurements

on added service, due to different need of radio resource reservations


Realtime User Plane

� MTSI Speech Quality� MTSI Speech Path Delay

� MTSI Video Quality� MTSI Video Path Delay

Discussion onfollowing slides


� MTSI Audio/Video Synchronization

� MTSI Real-Time Text Failure Ratio� MTSI Real-Time Text Delivery Time


MTSI Speech Quality

� MTSI speech requires jitter buffer in terminal� Speech is very sensitive to exact playout time� The buffer handles variation in arrival time for sp eech frames

� Depth of jitter buffer is a compromise� Small buffer means low delay

Large buffer handles jitter variations better


� Large buffer handles jitter variations better

� Adaptive jitter buffer often used� Buffer depth changes when radio environment changes� Uses speech time-scaling to shorten or lengthen out put speech

during buffer depth adaptations

� Objective speech quality measurements currently dif ficult� ITU-T P.862 (PESQ) cannot handle time-scaling� Ongoing ITU-T P.OLQA standardization promises to han dle this


MTSI Real-Time Text Delivery Time

� Not an ordinary chat service� Chat services (e.g. MSN) typically transfers the wh ole line of text after

the user press ’Enter’

� Not a messaging service� Messaging services (e.g. SMS, MMS) typically are se ssionless

� Real-time text characteristics


� Real-time text characteristics� The text transfer is done during an ongoing session� Every character (or erasing of a character) is show n to the other party� Instant feedback, more like a real-life conversatio n than a chat

� Relevant measurements� Transfer delay and transfer failure� Delay requirements are in the order of 500 ms for a high-fidelity real-

time text feeling


Non-realtime User Plane

� MTSI Messaging Failure Ratio� MTSI Messaging Delivery Time

� MTSI File/Media Sharing Failure RatioExample onnext slide


� MTSI File/Media Sharing Mean Data Rate


MTSI Messaging Delivery Time

� MTSI messaging characteristics� Message exchange are done within the context of a s ession� Different media can be sent; text, speech, video et c.� Can be seen as ”MMS within a session”, but without th e size

restrictions of an MMS


Terminal IMS Core MTAS

SIP INVITE SIP INVITESIP INVITE to terminating network

SIP 200 OK (INVITE) from terminating networkSIP 200 OK (INVITE)SIP 200 OK (INVITE)

MSRP 200 OK MSRP 200 OK MSRP 200 OK

TCP Connection Set-up

MSRP SENDMSRP SENDMSRP SEND

IMS Client

User starts the messaging application Initate

messaging session signal

Message delivered signal

Message delivered notification

User sends messageSend message signal

MTSI Messaging Delivery Time

Delivery time depends on

message size


MTSI Registration Failure RatioMTSI Registration Time

MTSI Session Set-up Failure RatioMTSI Session Set-up TimeMTSI Session Add Failure RatioMTSI Session Add TimeMTSI Session Remove Failure RatioMTSI Session Remove Time

PoC Registration Failure RatioPoC Registration TimePoC Publish Failure RatioPoC Publish TimePoC Registration Failure Ratio (long)PoC Registration Time (long)PoC Session Initiation Failure Ratio (on demand)PoC Session Initiation Time (on demand)

PoC Session Media Par. Neg. Failure Ratio (pre)PoC Session Media Par. Neg. Time (pre)PoC Session Initiation Failure Ratio (pre establish ed)

MTSI vs. PoC Red = PoC “combination” parametersgreen = PoC “mode” parameters

MTSI speech and PoC share some common characteristics, but the


MTSI Session Completion Failure RatioMTSI Session Completion Time

MTSI Deregistration Failure RatioMTSI Deregistration Time

MTSI Speech Path Delay

MTSI Speech Quality

PoC Session Initiation Time (pre established)PoC Session Setup Failure Ratio (on demand)PoC Session Setup Failure Ratio (pre established)PoC Session Setup TimePoC Push to Speak Failure RatioPoC Push to Speak TimePoC Session Leaving Failure Ratio (on demand)PoC Session Leaving Time (on demand)PoC Session Leaving Failure Ratio (pre established)PoC Session Leaving Time (pre established)PoC Deregistration Failure RatioPoC Deregistration TimePoC Busy Floor Response Failure RatioPoC Busy Floor Response TimePoC Talk Burst Request Failure RatioPoC Talk Burst Request TimePoC Talk Burst Cut off RatioPoC Talk Burst Packet Drop RatioPoC Voice Transmission Delay (first)PoC Voice Transmission Delay (others)PoC Speech Quality

common characteristics, but the different ”modes” for PoC requires

more KPIs


Summary

� IMS-based services promises an enhanced end-user ex perience� Allows easy combination of different media types wi thin one

session

� Achieving good end-user quality is vital for succes sImportant to use relevant KPI:s for the MTSI servic es


� Important to use relevant KPI:s for the MTSI servic es

� ETSI STQ Mobile is well prepared with ongoing stand ardization work for MTSI services

� ITU-T is also currently standardizing new algorithm s for objective speech and video quality assessment, suitable for M TSI services

Thank you for your attention!

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