doc.: ieee 802.11-06/0039r1 submission january 2006 clifford tavares, hitachislide 1 on video over...

January 2006

Clifford Tavares, Hitachi

Slide 1

doc.: IEEE 802.11-06/0039r1

Submission

On video over 802.11

Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

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Date: 2006-01-17

Name Company Address Phone email Clifford Tavares Hitachi America

Ltd. 2000 Sierra Point Pkwy. Brisbane, CA 94005

408-718-5260 [email protected]

Todor Cooklev 121 Miramonte Dr. Moraga CA 94556


Sudhanshu Gaur Hitachi America Ltd.


Authors:

January 2006


Slide 2

doc.: IEEE 802.11-06/0039r1

Submission

AbstractThe intent of this presentation is to explore interoperation and end-to-end performance in WLAN transmitting video.

We identify a use case for video over 802.11 and establish relevant requirements. Next, we present some studies on the scalability issues with 802.11e, the use of random AIFSN, direct link performance, video prediction based traffic shaping, etc. These studies show improvement in the performance of the WLAN independent of the physical layer.

Acknowledgment: The presentation includes input from Boeing, Samsung, and Nortel

January 2006


Slide 3

doc.: IEEE 802.11-06/0039r1

Submission

Outline

• Use cases for video over wireless

• Relevant requirements for video over fixed home WLAN

• Scalability issues with 802.11e

• Random AIFSN mechanism

• Direct link vs. “AP mode”

• Traffic shaping based on video prediction

• Results from previous presentations

• Conclusions

January 2006


Slide 4

doc.: IEEE 802.11-06/0039r1

Submission

References• Some relevant prior use cases

– Mesh networks for home entertainment, 802.11-04/0530r0 (ComNets, Philips) – Home Usage Model for HT WLAN Systems, 802.11-03/489r0 (Samsung)– Requirements for high-rate WPAN for video, IEEE 802.15-02/047r0 (Texas

Instruments)– Video testing strategy, IEEE 802.11-05/0887r0 (Intel)

• Other references– C. Tavares, T. Cooklev, “802.11 for high data rate multimedia transmission”,

doc. 802.11-0632r0, July 2005. – M. Hazra, R. Logan, “Delivering high-quality video over wireless

transmission,” Intel Developers Forum – C. Eliiott, Stream Synchronization for Voice over IP Conference Bridges, M.S.

thesis, McGill University, Montreal. – http://www.cs.uic.edu/~ifc/mmwsproc/zhang/acm/mm.html– http://www.cdc.gov/niosh/pdfs/FFRCSch4.pdf

January 2006


Slide 5

doc.: IEEE 802.11-06/0039r1

Submission

Use Case: Video over fixed wireless

over WLAN

HD Plasma Monitor

HD Plasma Monitor

Bedroom 1Bedroom 2

Living Room

HD Plasma Monitor

Desktop

DVD Player Video Display

CableBroadband

Home Gateway/APSet-top BoxA/V Server

V1

V2

V3

VN

BE1

January 2006


Slide 6

doc.: IEEE 802.11-06/0039r1

Submission

User Requirements• Streaming Video

• Video phones (full duplex) not popular– Very low BW control uplink (e.g. for remote control)

• Little or no mobility

• Powered devices

• CE Display/Sinks:– Game console

– HDTV

– HDD/Storage

• Zero configuration effort

• Similar performance to wired video

January 2006


Slide 7

doc.: IEEE 802.11-06/0039r1

Submission

General requirements for video• Video Quality

– Bandwidth – Latency– Jitter– Packet loss – Inter stream synchronization (Broadcast only)

• Network performance – Capacity - number of simultaneous streams– Static/dynamic priority– Mode selection: direct link or “AP mode”, EDCA vs. HCCA (detection of HCCA

peers)– Automatic channel selection mandatory? – Fairness to BE

• Environment

– Range – Properties of walls

January 2006


Slide 8

doc.: IEEE 802.11-06/0039r1

Submission

Traffic specification• Video operation profiles (TSPECS):

– ACK Policy, Service Interval, Minimum/Peak Data Rate, Maximum Burst Size, Minimum PHY Rate, Delay bound, Surplus Bandwidth Allowance

Medium type

Bandwidth (Mb/s)

Latency (ms)

Packet jitter (ms)

Bit error rate

Video 20 250 5 < 10-6

January 2006


Slide 9

doc.: IEEE 802.11-06/0039r1

Submission

Additional specifications

• Bit error rate < 10-6• Inter-stream synchronization (broadcast only) – less

than 120 ms• Range 20 m• Properties of walls

(http://www.cdc.gov/niosh/pdfs/FFRCSch4.pdf)– Brick configuration– Dielectric and conductivity constants – Thickness of concrete– Finishing (glass, reinforced concrete, etc.)

January 2006


Slide 10

doc.: IEEE 802.11-06/0039r1

Submission

Transmission performance of 102mm concrete (Attenuation vs frequency)

January 2006


Slide 11

doc.: IEEE 802.11-06/0039r1

Submission

Wireless Video ProtocolsWhy Does Boeing Care?

• Boeing is implementing wireless for in-flight entertainment

• It is a high density environment with multipath issues

• Requires more Efficient Use of Limited Bandwidth

• Requires higher Video Quality to Passengers at lower BW

• Requires Support for varying sizes of Displays

January 2006


Slide 12

doc.: IEEE 802.11-06/0039r1

Submission

Video Quality Requirement (Ref. IEEE 802.11-05/0887r0)

• Both videos have same level of blockiness

• However the perception is different– In the top sequence the

blockiness occurs in a visually acceptable area (the background)

– In the bottom sequence, the blockiness occurs in a visually unacceptable area

• A content adaptive FEC scheme may be used

January 2006


Slide 13

doc.: IEEE 802.11-06/0039r1

Submission

Fairness to BE Traffic

• As number of video streams increase, BE traffic is starved of bandwidth

• May be we can sacrifice a little bit of video bandwidth to achieve reasonable BE traffic

1 2 3 4 50

1

2

3

4

5

6

7

Number of Video Streams

Th

rou

gh

pu

t p

er Q

ST

A (

Mb

ps)

o Video

x Best Effort

802.11e

Desired?

Simulation Parameters– Default EDCA values,

54 Mbps PHY

– 1 BE stream

January 2006


Slide 14

doc.: IEEE 802.11-06/0039r1

Submission

Dynamic Priority

• Changing the priority level to AC3 improves the performance

• Network adaptive priority leads to better network utilization

Simulation Parameters– Default EDCA values,

54 Mbps PHY

– 5 traffic streams belonging to AC0

January 2006


Slide 15

doc.: IEEE 802.11-06/0039r1

Submission

Random AIFSN Mechanism

• Arbitration inter-frame space (AIFS) is one of the EDCA parameters used to ensure traffic differentiation

• Each AC has fixed AIFS duration associated with it. The smaller the AIFS the higher the medium access priority

• Proposed Mechanism– Each AC defers for

– AIFSN is random with a certain probability density function

– For example the distribution can be uniform.

• Advantages– More priority levels

– Less collisions within an AC; higher throughput

– Better network performance

slot timeAIFS AIFSN SIFS

January 2006


Slide 16

doc.: IEEE 802.11-06/0039r1

Submission

Simulation with Random AIFSN• Simulation Parameters

– 54 Mbps PHY, 12 nodes – 4 BE, 4 Video and 4 Voice

– Default EDCA parameters for all ACs except for random AIFSN for video

Global Throughput per AC Global Delay per AC

January 2006


Slide 17

doc.: IEEE 802.11-06/0039r1

Submission

AP Vs Direct Link (Animation)Access Point Controlled Traffic Direct Link Traffic

January 2006


Slide 18

doc.: IEEE 802.11-06/0039r1

Submission

Video Prediction with 802.11eGenerate MPEG video source

802.11e QSTA EDCA MAC

802.11 PHY

Obtain VI AC queue length

Adjust EDCA TXOP_limit of VI AC

At the time of winning channel access

WPI WPP WPB

I frame P frame B frame

WP: wavelet predictor

VI: Video

AC: Access Category

Predicted I,P,B frame size

Video Predictor

January 2006


Slide 19

doc.: IEEE 802.11-06/0039r1

Submission

802.11e MAC dynamic adaptation method using Video Prediction

• Video prediction– Predict the next MPEG frame size (I, P, B frames of MPEG

stream) using the wavelet domain Normalized Least Mean Square (NLMS) algorithm

• Simulation Environment– A BSS with 20 QSTAs and 1 QAP

– 802.11e EDCA MAC & 802.11b 11Mbps PHY

– 1 video stream (VI, 1.5 Mbps MPEG-1), 5 voice streams (VO, 64Kbps) and 4 FTP best effort traffic (BE, 1Mbps)

– simulation time: 300 sec

January 2006


Slide 20

doc.: IEEE 802.11-06/0039r1

Submission

Simulation results

Throughput of video (bps) vs. simulation time (min)

with video prediction

without video prediction

Network throughput (bps) vs. simulation time (min)



January 2006


Slide 21

doc.: IEEE 802.11-06/0039r1

Submission

Simulation Results (cont.)

Packet drop (packet/s) vs. simulation time (min) (time average)



Throughput of voice (bps) vs. simulation time (min) (time average)



January 2006


Slide 22

doc.: IEEE 802.11-06/0039r1

Submission

Previous conclusions

• Video over wireless is an important new application

• Jitter and Error Tolerance are not part of TSPEC

• Content adaptive FEC

• Two dimensional QoS model (Priority and BER)

• DLP is provided, but a direct link mode selection mechanism is missing

• Throughput analysis of HCCA and EDCA

• Further MAC-level extensions for video can overcome the limitations and ensure multiple video channels in home networking

January 2006


Slide 23

doc.: IEEE 802.11-06/0039r1

Submission

Conclusions

• Use cases for wireless video home networking have been defined

• Fairness to BE needs to be considered

• 802.11e doesn’t scale (Dynamic priority needs yo be considered)

• Random AIFSN based channel access mechanism can improve the performance of 802.11e

• Direct link mode switching mechanism is required

• Video prediction can be used to improve the network performance

doc.: ieee 802.11-06/0039r1 submission january 2006 clifford tavares, hitachislide 1 on video over...

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