VoLTE video telephony – a communication evolution

Per Synnergren

Expert Mobile Broadband Services and Performance

Ericsson AB

2013-10-08

VoLTE video telephony is happening now!

1. VoLTE video telephony natural part of the communication evolution

2. Launched in commercial operation

3. More launched coming next 12 months

4. Quality level set correctly in launched networks

5. Radio environment in launched network close to ideal

6. Normal network environment will require additional media functionality – adaptation

7. Further work in the industry may be required to secure the video quality

History of VoLTE video telephony (GSMA IR.94)

Transformationinto GSMA PRDs

OneVoiceNov 2009

PRD IR.92

Voice UNI

PRD IR.94

Video call additions

Extensions of IR.92

Subset and e2e systemization

MMTel

Interoperability testing PRD IR.39

HDVC

Communication Evolution

RCS-e

VoLTE

RCS 5.x

Co

nsu

mer

Co

mm

un

ication

HD VoiceHD Video

calling

Multi-device and Multi-

access

BE VoIP BE Video

CS voice

HD Voice

RCSe feature set

Additional differentiators

Alignment to RCS5

VoLTE

RCS feature set

Interoperable voice and SMS

over LTE (IR.92)CS-

coexistence

Advanced services roaming

Europe

USAJapanKorea

Market situation

1. >6 Million commercial VoLTE users (September 2013)

• SKT 4.5M• LGU+ 1.5M • KT 200k

2. 3 networks in commercial operation

3. Major launches planned end-2013/beginning 2014

4. Video part of launched networks, planned in many launches

5. ~40 commercial models launched

Voices from korean customers

“Very impressed with video-call quality”

“The voice is definitely clear like I’m using a microphone on a computer”

“Less background noise. Maybe couldn’t hear any noise at all”

“Call connection ringtone sounds like a live music”

“I can’t notice any difference time to time.”

Speed of LTE in a crowded area is amazing

“It’s obviously way better Crisp, clear video quality compared to 3G video call”

Very dense network planning in Korea

= Best possible networks to launch VoLTE/video telephony in!!!

Quality of Experience is important: Secure video quality!

1. Video telephony over radio; a challenging application/access combination!

2. It requires; low latency, low error rates and high bit rates

0.1 1 3 15Delay from capturing the video until it is viewed [seconds]

Video Calling and Video Conferencing

Video Clip Services

TV Broadcast and Live Webcast

Video Sharing

<0.4s

1.5

2.0

2.5

3.0

3.5

4.0

4.5

225kbps 350kbps 500kbps 650kbps 800kbps 1000kbps 1500kbps

360p Upscale 25Hz

480p 25Hz

Video bitrate for enjoyable quality

MO

S-VQ

S

Video bitrate

VGA video format, H.264 video codec

Typical target to be above

Typical target to be above

What is used in deployed networks?

• 480p (VGA) native video format used in deployed networks

• Video bitrate >=500 kbps as recommended

Quality aspects - Visible degradations

• End-user service expectations– Varies between video services

• Assumption of acceptable visible degradations:– Video Calling, Video Sharing and

Video Conferencing• Once per 20 seconds

– Live Web Cast• Once per 15 minutes

– TV Broadcast/Video Clip• Once per 45-60 minutes (basically error free)

PLR: 10-3

PLR: 10-5

PLR: 10-6

Can it be achieved in field?

Table: 99% percentile and average of PLR (high load, low SINR for one device)

Table: 99% percentile and average of PLR (low load, high SINR for both devices)

Table: 99% percentile and average of PLR(high load, high SINR for both devices)

The challenge we should work further on is …

… how to offer a Video Call in an real LTE network deployment planned for MBB and Voice?

>500 kbps

>? kbps

x dB

What happens in the “yellow area”?

10 15 20 25 300

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Process time [s]

Delay [s]

Packet delayLost packet

Situation improved by video bitrate adaption!

10 15 20 25 300

100

200

300

400Bitrate [kbps]

10 15 20 25 300

0.1

0.2

0.3

0.4Packet delay [s]

Process time [s]

10 15 20 25 30

100

200

300

400Bitrate [kbps]

10 15 20 25 300

0.5

1

1.5

2

Process time [s]

Packet delay and lost packets

Packet delay [s]Packet lost

Congestion problem detected in advance to avoid packet loss and delay increase

Abrupt reduction in video bitrate when congestion is identified in UE

UE triggered adaptation Network triggered adaptation

Possible to have mooth reduction in video bitrate, when congestion starts to build up

Sender based adaptation

RTP

RTCP SR/RRBandwidth estimatorBandwidth estimator

• Reacts on data in RR/SR, e.g. fractional loss

• Estimates available bandwidth

• If video rate > available bandwidth

• Sends rate request to the controller

• Reacts on data in RR/SR, e.g. fractional loss

• Estimates available bandwidth

• If video rate > available bandwidth

• Sends rate request to the controller

Me

dia

sen

der

Needs regular RTCP reports during normal operation

Me

dia

re

ceiv

er

ControllerController

EncoderEncoder

Receiver based adaptation

Rate controlRate control

Arrival time model and channel usage detectionArrival time model and

channel usage detection

Me

dia

Re

ceiv

er

Over-use

Normal

Under-use

Over-use

Normal

Under-use

Video frameUses filterUses filter

• Adjusts Receiver Bandwidth Estimation

• Send rate requests

• Adjusts Receiver Bandwidth Estimation

• Send rate requests

Works on inter-frame arrival delay

Rate request send to the sender using RTCP TMMBR

RTCP (TMMBR)

RTP

Me

dia

Se

nde

r

ControllerController

EncoderEncoder

ECN trigger

Rate controlRate control

ECN and channel usage detection

ECN and channel usage detection

Me

dia

Re

ceiv

er

With ECN

RTCP (TMMBR)

RTP

• GSMA IR.94 does not mandate video adaptation functionality

• 3GPP do specify the protocols needed, but not procedures/guidelines

• Video adaptation may need operator specific multivendor test and verification

• Something for IMTC to consider?

Interoperability not (fully) secured!

VoLTE video telephony is happening now!

1. VoLTE video telephony natural part of the communication evolution

2. Launched in commercial operation

3. More launched coming next 12 months

4. Quality level set correctly in launched networks

5. Radio environment in launched network close to ideal

6. Normal network environment will require additional media functionality – adaptation

7. Further work in the industry may be required to secure the video quality