1. Thesis Presentation Supervisor: Prof. Jörg Ott Student: Junxi Yin Espoo, 11.21.2012

2. Topic Mobile Implementation of Floating Content Service

3. Outline Introduction Delay-tolerant Networking Floating Content Service Application Design and Implementation Test and Evaluation Conclusion and Future Work References Appendix

4. Background Scenarios where traditional Internet is not working well Flea market Travelling Rural areas Supermarket Developing countries …

5. Background Why DTN in mobile? Development of DTN technology Growing mobile market (Cheaper devices) Growing usage of mobile devices Growing usage of location service Open source sw and tools

6. Objective 1. Theoretical studies 2. Simulations 3. Implementation and test

7. DTN DTN=Delay-Tolerant Networking [1] Designed for extreme conditions Protocol Data Unit - Bundle Convergence Layer Custody Transfer Store-and-Forward

8. Data is stored throughout the network and forwarded when a better chance comes in hopes that it will eventually reach its destination – Opportunistic Communication

9. Floating Content Service A DTN-based localized information sharing service exclusively dependent on mobile phones and other mobile devices. [2] As long as there are enough supportive mobile devices around in the anchor zone to replicate and store a piece of content, it floats.

10. Replication Probability Replication Probability According to Distance from Message Center Since replication is based purely on the location of nodes, in a simple case, every node in the anchor zone should have a copy of the item. In practice, the replication works as follows.

11. Simulations ONE Simulator=Opportunistic Network Environment simulator -Written in Java -Agent-based, discrete event, network simulator -Support Mobility Models -Several built-in DTN routing algorithms [3] More Information: http://www.netlab.tkk.fi/tutkimus/dtn/theone/

12. Location Error Consideration Performance of Floating Content Service without Location ErrorPerformance of Floating Content Service with Location Error Please refer to Floating Content: Information Sharing in Urban Areas to get more details about the performance of Floating Content service

13. A Closer Look Compared floating performance as a function of lifetime Conclusion: The location error has very limited effect to the performance of Floating Content application

14. System Design

15. System Implementation Open source tools, no costs at all. Java Android Floating Content API SQLite Database XML

16. Action Flow

17. Screenshots

18. Test Results Transfer Speed of Floating Content Service between Two Devices The transmission speed using Floating Content service is similar with the actual Wi-Fi speed between only two devices.

19. Future Work Deploy a systematic testbed to better evaluate the performance of Floating Content service in a real world environment Better user interface design

20. References [1] Forrest Warthman, Delay-Tolerant Networks (DTNs), A Tutorial, May 2003. [2] J. Kangasharju, J. Ott, and O. Karkilahti, Floating Content: Information Availability in Urban Environments, in Proc. of IEEE Percom 2010, Work in Progress session, March 2010. [3] A. Keränen, J. Ott, and T. Kärkkäinen, The ONE Simulator for DTN Protocol Evaluation, in SIMUTools 09:Proceedings of the 2 nd International Conference on Simulation Tools and Techniques, NewYork, NY, USA: ICST, 2009.

21. Thank You ! Junxi Yin junxi.yin@aalto.fi