Network Coding for Wireless Grids

Frank H.P. FitzekMobile Device Group

www.fitzek.netfrank@fitzek.net

wireless grids

wireless grids

• Based on user cooperation, but why should users cooperate?– Create cooperation enabling services

– Create trust and pay off tolerance

– „emoney“ bad idea

• Which kind of services can be supported– All (unicast/multicast/etc)

– Some examples

nice idea, but …

• Analytical and simulative investigation

• A large number of testbeds to verify our ideas and the get real feedback for our further investigations (it is a two way street)

cooperative localization

cooperative video service

BS

Cooperative group

T2T3

D1

D2

D3

D1

D2 D3

cooperative download

• Using GPRS and Bluetooth for cooperation among two terminals for file sharing

• N70 Mobile Phones• Symbian/C++

implementation• Tit for Tat Strategy• Benefit in the download

time (reduced by a factor of two), the energy (going down to 56%) and (perhaps) reduced service costs

• Fit with analytical results

cooperative web browsing

problem

• Interference in the cooperation (local) cluster is high and can cause long delays and high energy consumption

• Improve the local communication

network coding

end2end, network layer or higher

network coding for wireless grids

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Scenario: Wheel++•12 mobile devices in total•Four flows (one per cluster)•Each device receives cellular input•Just relaying to exchange

sending receiving idle

Oneactivity matrix

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All activity matrixes

20 24 16

All idle matrixes

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SUM 20 24 196

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time slots

Scenario: Wheel++•12 mobile devices in total•Four flows (one per cluster)•Each device receives cellular input•Network coding within each cluster

sending receiving idle

Oneactivity matrix

4 6 2

All activity matrixes

16 24 8

All idle matrixes

0 0 144

SUM 16 24 152

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time slots

Scenario: Wheel++•12 mobile devices in total•Four flows (one per cluster)•Each device receives cellular input•Network coding over all cluster•Device 2 is doing the most work

sending receiving idle

Phase 1 4 8 36

Phase 2 8 62 26

Phase 3 1 8 3

SUM 13 78 65

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Phase 1 Phase 2 Phase 3

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Results

network coding

N810 testbed S60 testbed opensensor testbed

channel measurement

25m

channel measurement

channel measurement

mac measurement

Not used

PictureViewer

• Convey pictures of your mobile phone to your neighbors

• How to do this?

RLNC on Mobile Phones• Implementation with larger finite field

Results of Preanalysis (g=64)

Sytematic Coding

Coding throughput on Nokia N95Nokia N95-8GB, ARM 11 332 MHz CPU, 128 MB ram, Symbian OS 9.2

Energy Consumption

network coding and cooperation

Cooperationw & w/o nc

nc

SoA

Books

F.H.P. Fitzek and M. Katz. Cooperation in Wireless Networks: Principles and Applications -- Real Egoistic Behavior is to Cooperate!. 2006. Springer.

F.H.P. Fitzek and M. Katz. Cognitive Wireless Networks: Concepts, Methodologies and Visions Inspiring the Age of Enlightenment of Wireless Communications. 2007. Springer.

F.H.P. Fitzek and F. Reichert. Mobile Phone Programming and its Application to Wireless Networking. 2007. Springer.