QoS /QoE in the context of videoconferencing services over...

QoS /QoE in the context of videoconferencing services over LTE/4G networks.

NDIAYE Maty– PhD student within France Telecom / Orange Labs

ETSI workshop on telecommunications quality matters

28/11/2012, Vienna (Austria)

2

Agenda

part 1 Scope of the current study

part 2 Videoconferencing services and associated codecs

part 3 LTE/4G in a nutshell

part 4 Goal of the experiment

part 5 Description of the experimentation

part 6 IP results

part 7 Summary and next step


3

Scope of the current study

With the important technology advances in the area of mobile devices, the

development of data traffic on current 3G mobile networks is rocketing :

Emergence of voice and video services, in particular video conferencing for

personal and professional use over mobile devices

The growth of consumer demands for multimedia services generates huge

amount of video traffic on mobile networks

This increase of mobile data consumption pushes operators to invest in new

mobile broadband networks relying on advanced radio and IP network

technologies

3GPP has then defined a new standard LTE/4G [Release 8]

integrating several quality levels to cope with these new applications and services


4

Videocalling services and associated codecs

With LTE,

– more bandwidth and less latency for streaming multimedia contents

– some applications are very sensitive to network/radio conditions.

– there is a need to check that conversational services will perform efficiently with

this new mobile network.

To ensure the best Quality of Experience (QoE) when dealing with mobile

video calls

- Selection of video and audio codecs in line with the capabilities of bearers

- The user expectations (low-cost, regular, premium services)

- Tradeoff between the right bitrate and the highest video and audio quality.

No specific media codecs are defined for these types of services over LTE :

Some recommendations propose to use the existing codecs (AMR, AMR-WB

(voice) and H.263, H.264 (video)

However, active works are ongoing to develop High-Efficiency Video Coding (HEVC)

(video) and Enhanced Voice Service (EVS)(voice and audio). QoS /QoE in the context of videoconferencing services over LTE/4G networks.

5

LTE/4G in a nutshell

Two main components: Evolved Packet Core

(EPC) and e-UTRAN .

Throughput expected around 100 Mbps in DL

and 50 Mbps in UL

Reduced latency complying with the expectations

of real-time applications

QoS management through bearers set-up.

New radio technologies : OFDMA, SC-FDMA and

MIMO.

All IP architecture, relying on IMS system

handling SIP protocol. Figure 1 : LTE Architecture (cisco.com)

Figure 2 : Qos managment


6

Goal of the experimentation

What ? : The main target is to study the usability of existing standardized codecs

when dealing with videoconferencing services over currently deployed LTE/4G

networks.

Where ? : Experiments were launched with the use of available LTE dongles and

on the ImaginLab 4G/LTE experimental platform deployed in Brest (France) by

Images and Networks French Cluster. (http://www.images-et-reseaux.com/en)

How ? : Connections were set-up using “best effort” mode (non-guaranteed QoS),

without mobility in the present case, close to the antenna (approximately between

150-200m), within a building, using 2,6 GHz radio frequency.


7

LTE cartography (source : Images and Networks French Cluster)


8

Technical description of the experimentation

Experimentation tools used :

Orange Labs internally developed probe called “SondeQoS” :

- The tool is able to set-up and tear-down videocall using the SIP protocol.

- Several codecs are implemented when setting-up end-to-end calls over the LTE

network with several configurations (e.g. H264 / G722.2 or H263 / G711)

- Different reference audio and video files can be injected within the tool so as to stream

different contents (image resolution, frame per second, bitrate, etc…)

- Several key performance metrics can be gathered at the end of each call and the

outcoming audio and video files can be stored for quality inspection

CIF( 320x288)

resoulution 4CIF( 704x576)

resoulution

720p( 1080x720)

resoulution


9

QoS & QoE over LTE/4G

Description of the experimentation: simulation of end-

to-end calls over the LTE/4G via SondeQoS probe


10

Interpretation of IP results

MOS=[4.18 4.42] Call registration =[04.41ms 05.87ms]

Call establishment=[02.189ms 04.278ms]

Percentage of audio lost packets= [0% 0.07%]

Percentage of video lost packets= [0% 0.15%]

Jitter=[0ms 1.27ms]

Codec flow: G.711 = 64 kbps

AMR-NB = variable rate & Voice activity detection(VAD)= on (1)

G.722 = 64 kbps G722.1 = 2*32 kbps stereo

AMR-WB = 12.65 kbps & VAD =1

H.263 profile= Baseline profile Max picture rate= 625 picture s /sec


Configuration

Parameters

H.263/G.711

H.263/AMR-NB

H.263/G.722

H.263/G.722.1

H.263/AMR-WB

Call registration

04.79ms

05.44ms

04.41ms

05.30ms

05.87ms

Call establishment 02.189 ms 02.756 ms

04.278 ms 03.361 ms 02.741 ms

Throughput

(average)

Audio

UL = 87.31 kbps

DL =85.60 kbps

Video

UL = 861.80 kbps

DL = 1300.92 kbps

Audio

UL = 8.98 kbps

DL = 7.80 kbps

Video

UL= 784.19 kbps

DL = 1417.47 kbps

Audio

UL = 85.60 kbps

DL = 85.60 kbps

Video

UL= 1608.20 kbps

DL = 1380.62 kbps

Audio

UL = 85.60 kbps

DL = 85.60 kbps

Video

UL= 1112.68 kbps

DL = 1049.85 kbps

Audio

UL = 9.91 kbps

DL = 9.42 kbps

Video

UL = 1010.56 kbps

DL = 1304.97 kbps

MOS

Audio

UL & DL = 4.36

Audio

UL & DL ≈4.41

Audio

UL = 4.18

DL = 4.23

Audio

UL = 4.40

DL = 4.35

Audio

UL = 4.37

DL = 4.42

Jitter

(average)

Audio

UL = 0.01 ms

DL = 0.44 ms

Video

UL =0.16 ms

DL= 0.05 ms

Audio

UL = 0.21 ms

DL = 0.95 ms

Video

UL =0.17 ms

DL= 0.26 ms

Audio

UL = 0.01 ms

DL = 0 ms

Video

UL =0.15 ms

DL= 0.11 ms

Audio

UL = 1.20 ms

DL = 1.14 ms

Video

UL =0.16 ms

DL= 0.03 ms

Audio

UL = 1.27 ms

DL = 0.75 ms

Video

UL =0.17 ms

DL= 0.05 ms

Percentage of lost

packets

Audio

UL = 0.03%

DL = 0.02%

Video

UL = 0.02%

DL = 0.01%

Audio

UL = 0.03%

DL = 0%

Video

UL = 0.15%

DL =0%

Audio

UL = 0.06%

DL = 0%

Video

UL = 0.07%

DL =0%

Audio

UL = 0%

DL = 0.03%

Video

UL = 0%

DL =0.04%

Audio

UL = 0.07%

DL = 0%

Video

UL = 0.02%

DL =0%

11

Interpretation of IP results

MOS=[4.22 4.42] Call registration =[04.16ms 06.16ms]

Call establishment=[02.171ms 03.361ms]

Percentage of audio lost packets= [0% 0.03%]

Percentage of video lost packets= [0% 0.08%]

Jitter=[0ms 1.35ms]

Codec flow: G.711 = 64 kbps

AMR-NB = variable rate & Voice activity detection(VAD)= on (1)

G.722 = 64 kbps G722.1 = 2.32 kbps stereo

AMR-WB = 12.65 kbps & VAD =1

H.264 profile= Baseline profile Level= level 2

Max picture rate= 625 pictures /sec


Configuration

Parameters

H.264/G.711

H.264/AMR-NB

H.264/G.722

H.264/G.722.1

H.264/AMR-WB

Call registration 05.06ms 05.04ms 04.16ms 06.16ms 04.91ms

Call establishment 02.171ms 02.186ms

02.309ms 03.361ms 02.457ms

Throughput

(average)

Audio

UL = 83.88kbps

DL =85.60Kbps

Video

UL = 1353.31kbps

DL = 1399.15kbps

Audio

UL = 8.28kbps

DL =7.80 kbps

Video

UL= 1220.56kbps

DL = 1655.55Kbps

Audio

UL = 82.17kbps

DL = 85.60Kbps

Video

UL= 1311.35kbps

DL = 1912.02Kbps

Audio

UL = 85.60kbps

DL = 85.60kbps

Video

UL= 1112.68kbps

DL = 1049.85kbps

Audio

UL = 33.01kbps

DL = 9.42kbps

Video

UL = 1129.49kbps

DL =1136.97 kbps

MOS

Audio

UL = 4.36

DL = 4.33

Audio

UL = 4.42

DL = 4.42

Audio

UL =4.24

DL = 4.22

Audio

UL = 4.40

DL = 4.35

Audio

UL =4.42

DL = 4.42

Jitter

(average)

Audio

UL = 0.01ms

DL = 0.94ms

Video

UL =0.02ms

DL= 0.04ms

Audio

UL = 0.09ms

DL = 0ms

Video

UL =0.03ms

DL= 0.01ms

Audio

UL = 0.02ms

DL = 0 ms

Video

UL =0.02ms

DL= 0.03ms

Audio

UL = 1.20ms

DL = 1.14ms

Video

UL =0.16ms

DL= 0.03ms

Audio

UL =1.35 ms

DL = 0.63ms

Video

UL =0.07ms

DL=0.01ms

Percentage of lost

packets

Audio

UL =0.03 %

DL = 0 %

Video

UL = 0.07%

DL = 0%

Audio

UL =0 %

DL = 0%

Video

UL = 0.07%

DL =0.04%

Audio

UL = 0.02%

DL = 0%

Video

UL =0.08 %

DL =0%

Audio

UL = 0%

DL = 0 %

Video

UL =0 %

DL =0.04%

Audio

UL = 0%

DL = 0%

Video

UL = 0%

DL =0.04%

12

Encountered difficulties

Difficulty when connecting the LTE/4G dongle to a Linux environment:

The Operating System Ubuntu seems the most flexible when dealing with these

devices

Resolved thanks to AT commands (3GPP TS 27.007 V11.3.0 (2012-06)).

Non-conformity of the specification implementation.

SIP Register messages have to be customized so as to register with the IMS call

manager

Interoperability issues of the firmware version with the LTE/4G architecture

In some cases, the dongle firmware has to be upgraded or downgraded to

work correctly with the underlying LTE platform

The current underlying system was not able to manage differenciated QoS

The tests were run so far within a building, which show that 2,6 GHz Frequencies are

not well-suited for in-door tries

The LTE connection is asymmetrical so that the QoS on the UL and DL may be very

different


13

Summary

A first experiment of videocalling on experimental LTE network

These trials were performed using a true IMS infrastructure (Session Border

Controller, IMS Call Server, end-to-end delays, real-life variable radio conditions)

Several LTE dongles from different vendors were tested over Linux and

Windows

An internally developped tool was made ready for operational

measurements

This set of tests give a better knowledge about metrics to calculate (call

establishment time, registration time, bandwidth, loss, jitter)

Different resolutions of images and audio and video coding schemes were

used

The asymmetrical behaviour of the LTE connection is an issue that may

have impact of the choice of codec.

The 2,6GHz Frequencies are not well-suited for in-door tries


14

Next steps

Integrate outdoor mobility, distance to cell in real-live network

QoS management ( PCRF to be included) with the addition of different

configuration parameters (such as QCI, ARP or DSCP)

Tests under variable radio conditions (network disturbance tools)

Integration of new codecs (such as OPUS or HEVC (2013))

Subjective testing


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QoS /QoE in the context of videoconferencing services over...

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