1. 1 SOWER: Self-Organizing Wireless Network for Messaging Márk Félegyházi {mark.felegyhazi, srdan.capkun, jean-pierre.hubaux}@epfl.ch Srdjan Čapkun Jean-Pierre Hubaux Laboratory for computer Communications and Applications, Swiss Federal Institute of Technology (EPFL) – Lausanne, Switzerland TERMINODES Project (NCCR-MICS) http://www.terminodes.org

2. 2 SOWER: Self-Organizing Wireless Network for Messaging Intro to ad hoc networks Motivation System approach Connectivity investigations: measurement and simulations Conclusion and future work

3. 3 Ad Hoc Networks self-organizing network – no infrastructure each networking service is provided by the nodes themselves devices powered by a battery – energy constraints

4. 4 Motivation – Cellular Networks Short Messaging (SMS): a simple way of communication → popular does not require high bandwidth delay tolerant (in the order of tens of seconds / minutes) BUT: price of SMS is extremely high infrastructure of base stations is complex and expensive: deployment and maintenance costs users have no alternative Future vision: self-organizing and robust short messaging new services / applications

5. 5 A Self-Organizing Wireless Messaging Network (SOWER) h Each user owns: m home device mobile device Home devices form a wireless backbone for message transmission Home devices are: power plugged – always on static devices same radio as mobiles

6. 6 Connectivity measurements (1/2) Parameters: laptops with 801.11b wireless _cards random measurement points 1 Mbit/s channel capacity 100 mW transmission power Measurement campaign: 500m * 500m in Lausanne center

7. 7 Connectivity measurements (2/2) Main observation: With the device density equal to 220 devices/km2, we can provide a messaging network in a small city with a high coverage.

8. 8 Connectivity and coverage – simulation parameters Scenario building width street width 40 m Parameter Small city Metropolis Suburban 20 m 35 m 80 m 50 m 13.25 m Investigate the connected component of home devices Home devices uniformly placed in the buildings.

9. 9 Connectivity and coverage – simulations in 2D Connectivity: The proportion of the largest connected component Coverage: The proportion of the covered area of the largest connected component

10. 10 Connectivity – simulations in 3D Skyscrapers Small buildings – 5 floors

11. 11 Penetration requirements Scenario 2260 small (Berkeley) historic (Rome) modern (Berlin) ultra-modern (Manhattan) Population density (persons/km2) Required device density (devices/km2) Required market penetration (simulation for 100mW) Required market penetration (calculated for 1W, α=5) 8177 12500 25850 380 700 3000 5000 0.168 0.086 0.24 0.193 0.04 0.02 0.06 0.05

12. 12 Conclusion SOWER: All-wireless messaging network in cities self-organizing messaging network city-wide connectivity can be achieved with low market penetration capacity is sufficient to support messaging

13. 13 Additional technical issues Deployment of the network using existing infrastructure (dual-mode devices) higher transmission power (1 W in the US) Access to the infrastructure cellular networks high-speed Internet connections Capacity links have higher transmission rate (up to 54 Mbit/s nowadays) Addressing + Routing Security end-to-end security trust issues cooperation Pricing secure micropayment mechanism

14. 14 Future work extensive measurements in different city scenarios routing issues – include mobile devices in the packet forwarding charging and security issues implementation More info: web >> http://lcawww.epfl.ch/felegyhazi/http://lcawww.epfl.ch/felegyhazi/ email >> mark.felegyhazi@epfl.ch