1 video traffic optimization in mobile wireless environments using adaptive applications phd forum...

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Video traffic optimization in mobile wireless environments

using adaptive applications

Phd ForumUBICOMM 2008

David Esteban

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• Multimedia traffic : always very concrete characteristics

• Streaming data Availability = Priority

Video traffic in Wireless networks

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Video traffic in Wireless networks

• Wireless and mobile nature :– Optimization = Adaptation

– Upper layers MUST know the current status of the network.

– Vertical communication between layers

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Cross layering

• Wireless networking :– Multilayer problem– Layer dependency (either directly or not)

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Cross-layerTechniques

Cross layering


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Cross layering


Define a general concept of

communication between layers.

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Cross layering


Define a general concept of

communication between layers.

Concrete Algorithm ??

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Scenario definition

• AP based video conference environment:– One of the most common

applications.– Indispensable tool to

different scenarios. – Several kinds mobile

wireless users is continuously increasing.

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Previous workUSING INTERMEDIATE HARDWARE

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Previous workCOMPARISON TABLE

Costs

???

???

Using IntermediateHW

ExtraTraffic

Algorithmdefinition

OptimizationMobility

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Previous workCONDITIONS SET BY THE APPLICATION

• In this case, there is a software system which is checking the network status.

•The application will register status conditions on that system.

•when the system recognize a registered condition has been met, it will notify the application.

•The application will change its behavior consequently.

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Costs

??

Conditions set by application


ExtraTraffic

Algorithmdefinition


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Previous workUSING SIGNALING PACKETS

Some other previous research proposed the use of signaling packets as reporters of the QoS in the network and then send the information to the application.

Weak points :

- Inject more packets into the network could be harmful in critical situations

- There is no cross-layer algorithm specified to send the information from the lower levels to the application

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Costs

Using Signaling Packets

Conditions set by application


ExtraTraffic

Algorithmdefinition


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Current work

• Many approaches but weak points.• Proposed project :

– Check the status of the network :• As know the environment conditions is key point in this

project.

– Inform to the video application :• Because the higher layers MUST know this information.

– Adapt of behavior • In order to optimize the traffic injected into the network

depending of the environment.

– Avoid weak points• So, we will be able to improve the given solutions.

Current Work

Linux operating system

Gnome Desktop 2.20.1 in an

Ubuntu distribution.

Video App = Kopete v.0.12.7(Using KDE 3.5.8)

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First StepHOW THE NETWORK IS MONITORED?

-No use Control packets

-Local Updated information :

-/proc/net/dev/

-/proc/net/wireless/

-/proc/net/udp/

-/proc/net/tcp/

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-/proc/net/dev/


-/proc/net/udp/

-/proc/net/tcp/

Bytes, Packets, Errors

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-/proc/net/dev/


-/proc/net/udp/

-/proc/net/tcp/

Bytes, Packets, ErrorsIP addresses and ports

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-/proc/net/dev/


-/proc/net/udp/

-/proc/net/tcp/


Interface Status

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-/proc/net/dev/


-/proc/net/udp/

-/proc/net/tcp/


Interface StatusWireless Link & Signal

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Obtain this information in an organized way:

- C library “Liblink” .

- Look at the mentioned sources.

- Convert into independent variables.

- Easy format to operate with.

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SYNTAX :

linkd – t [miliseconds] [OPTIONS]OPTIONS :

-v Verbose Mode-i iface Set the polling interface-s sock_id Set the socket ID-f output_file Set the log file

LINKD

This library is invoked by a command called “linkd”

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-Use command :

-Invoke library will be summoned

-Get the required information in

-intervals equal to the specified polling time

-from the chosen interface.

-If verbose flag

-Store information in log file or

-Show it in the standard output.

Next step

Deal with this“organized” raw

information

Next step


information

Make the application change its behaviour

on the fly

Next step


information

Make the application change its behaviour

on the fly

Optimization = Adaptation

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Second StepHOW THE APPLICATION IS INFORMED ABOUT

THE NETWORK STATUS?

Information is gathered and organized into variables

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THE NETWORK STATUS?


“Quality Status”

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THE NETWORK STATUS?


“Quality Status”

Which information ??

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THE NETWORK STATUS?


Which information ??

Priority = wireless parameters. -/proc/net/wireless/

“Quality States”

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THE NETWORK STATUS?

The information obtained from that source would be :

-Quality-link : Link quality info (how good the reception is)

-Quality-level : Signal strength at receiver (dBm)

-Quality-noise: Silence level (no packet) at the receiver (dBm)

-Discarded-nwid : Number of discarded packets due to invalid network id.

-Discarded-crypt : Number of packets unable to decrypt.

-Discarded-frag : Number of fragmented packets

So a combination of these parameters will be use to define the “quality state” that will be the reference for the application.

Formula details

SNR (Signal-Noise relation): 10 * Log10 (Quality-level / Quality-noise)

- Bad values : between 0 and 1- Good values : higher than 5

Adjust parameterUse to give a significative value to the SNR

Ad = 5

Error relation :Given a interval t of time :

Eparam == 0;If (nwid(t))>(nwid(t-1)) Eparam == Eparam+5;If (crypt(t))>(crypt(t-1)) Eparam == Eparam+5;If (frag (t))>(frag(t-1)) Eparam == Eparam+5;

PREVIOUS PARAMETERS

Formula detailsFORMULA DEFINITION

Qlink + SNR – Ad – Eparam

10Qstate =

I.e.

Link Level Noise Nwid Crypt Frag SNR State

97 -28 -86 0 0 0 4.95 9(9.705)

Formula detailsFORMULA DEFINITION

Qlink + SNR – Ad – Eparam

10Qstate =

I.e.

Link Level Noise Nwid Crypt Frag SNR State

97 -28 -86 0 0 0 4.95 9(9.705)

47 -70 -89 0 10 0 1.08 3(3.808)

Quality States

• Applying the formula we will obtain a number from 0 to 9.

• The state only depends of the network conditions at that moment.


• That number is the number of the “quality state”. • 0 means the lowest quality state.• 9 represents that the environment is in its best condition

Layer Communication

• To inform the application about the “Quality status”.

• We will need specify a concrete Cross-layer algorithm

• So it will be a kind of intra-layer message passing system

Third Step

• Sent the state to the application

• Use primitives for inter-layer messaging• Primitives = Small units of information• Types of primitives.

COMMUNICATION BETWEEN LAYERS

Layer N

Layer N - m

Indication Response

Third Step

• Structure of a primitive :– Five fields :

• Protocol layer ID (which layer)• Protocol ID (which protocol entity)• Primitive class ID (which kind)• Parameters ( information sent )

• Portability of the primitives : Any information exchange method between layers can be used with this primitives.

COMMUNICATION BETWEEN LAYERS

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Forth StepHOW THE APPLICATION WORKS?

Web Cam

Yahoo! Protocol

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Web Cam

Yahoo! Protocol

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Web Cam

Yahoo! Protocol

Converts

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Web Cam

Yahoo! Protocol

Converts

Send to destination

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Forth StepHOW THE APPLICATION WILL RESPONSE?

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Conversion

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Conversion


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Conversion


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Forth StepInteraction between parts

System Folders

Quality States

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Web CamOriginal Frame

Converted Frame Store &

Send

System Folders

Quality States

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Send

System Folders

Once per “-t”

Quality States

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Send

System Folders

Once per frame

Once per “-t”

Quality States

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Send

System Folders

Once per frame

Once per “-t”

Quality States

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Evaluation

Preliminary Results

To check if the adaptation works we made real experiments establishing a video conference between a desktop and a laptop and checked the availability of the communication in different states for both adaptive and non adaptive models.

Preliminary Results

To check the system was working better thanks to the adaptation we made real experiments establishing a video conference between a desktop and a laptop and checked the percentage of packet loss in different states for both adaptive and non adaptive models.

Preliminary Results

[ Simulation ]

Future work

• How to get better results in the optimization (maybe adding or changing some sources, changing the formula, etc.).

• Test the adaptation of the information sent from the multi-conference server to the mobile nodes

• Implement the cross-layer algorithm details for the intra-layers messaging system from Application layer to Link layer.

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