1. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA MESH NETWORKING LABORATORY OF TELECOMMUNICATIONS George Sergiadis Associate Professor sergiadi@auth.gr

2. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Characteristics of the mesh networks Wireless by definition, infrastructure independent Formed in a spontaneous way, few to plan New nodes become routers to expand the network, scalable system Not only for internet access

3. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA THE FAB LAB SCOPE

4. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA A TYPICAL urban MESH Source: Microsoft Research

5. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA The announced Urban Mesh A Spanish firm is to sell subsidized routers as part of a plan to turn domestic wi-fi networks into public hotspots. Fon will sell wi-fi routers, which allow people to surf the net wirelessly, for $5 The company, which has financial backing from Google and Skype, aims to create public wi-fi networks street by street across the US and Europe. Tuesday, 27 June 2006

6. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA “ Africa Calling” – a highway to follow The number of mobile subscribers in 30 sub-Saharan African countries, not including South Africa, rose from zero in 1994 to more than 82 million in late 2004

7. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Rural mesh model - main components Hardware: Routers Antennas, cables Power supplies - Solar Structural solutions Software: Networking and dynamic multihop routing QOS control Management Security and privacy

8. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Routers Many vendors Many low cost solutions from 25 to 60 US $, but Most of them are not suitable for efficient rural meshes with few gateway points

9. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Mesh network Protocols Dynamic rerouting Efficient package management Additional services

10. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Antennas Price: $349.90

11. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Fab Lab mesh network approach

12. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Routers on trial Roofnet, an unplanned, multiroute mesh network developed at MIT's Computer Science and Artificial Intelligence Laboratory

13. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Fab Lab WiFi Antenna Projects Target: Very low cost, 1 or 2 US $ Low manufacturing sensitivity Fab Lab easily reproducible, by unskilled “Fablabers”, using the Fab Lab tools

14. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Fab Lab WiFi Antenna Projects Glass Antennas: 1.Quasi-isotropic antennas, mostly for interior use 2.Arrays for higher gain, for internal or low distance external use 3.Corner reflector antennas for point to point longer distance links

15. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Glass Antenna “Ingredients” Window Glass Self adhesive cooper CAD file Flexible low-loss cable, or no cable

16. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA “Isotropic” Antennas Gain 3 dbi

17. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Higher gain Arrays Directivity 120 0 H / 30 0 V- Gain 9 dbi

18. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Corner reflector antennas Directivity 60 0 H / 30 0 V - Gain 12 dbi

19. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Very high gain systems New approaches Planar structure Gain >20 dbi Low cost – glass dielectric Higher frequencies ( 5 GHz)

20. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Very high gain systems New approaches Planar structure - Gain >20 dbi

21. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Potential contribution of the mesh networks, especially in developing countries In business prosperity In employment In information spread In medical services In distance learning In natural disaster management Even in politics and democracy protection

22. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Conclusions Fab Lab reduces dramatically the cost of the mesh networking by producing the most expensive components, instead of buying them Fab Lab plans to design and manufacture also other expensive parts of the supporting infrastructure, by implementing its collective know-how

23. JUNE 2006SYMPOSIUM ON DIGITAL FABRICATION PRETORIA Thank you for your attention LABORATORY OF TELECOMMUNICATIONS George Sergiadis Associate Professor sergiadi@auth.gr