1. Communication Scheme for Loosely Coupled Mobile User Groups in Wireless Sensor Fields Euisin Lee, Soochang Park, Fucai Yu, Min-Sook Jin, and Sang-Ha Kim Department of Computer Engineering, Chungnam National University, Republic of Korea WCNC 2009 2009/05/19 Reporter: 黎炤均

2. OUTLINE INTRODUCTION DISTRIBUTED DATA GATHERING TREE ESTABLISHMENT DATA-CENTRIC INFORMATION MULTICASTING PERFORMANCE EVALUATION CONCLUSION

3. INTRODUCTION The tightly coupled user group means that there are direct communication channels among all mobile users. In case of the loosely coupled mobile user group, a wireless sensor network is only communication channel among the mobile users.

4. DISTRIBUTED DATA GATHERING TREE ESTABLISHMENT

5. DISTRIBUTED DATA GATHERING TREE ESTABLISHMENT (Cont.)

6. Kruskals’s algorithm

7. DISTRIBUTED DATA GATHERING TREE ESTABLISHMENT (Cont.)

8. DATA-CENTRIC INFORMATION MULTICASTING A. Agent Node Selection and Information Request B. Information Multicasting from a Sink to All Agent Nodes C. Information Relaying from Agent Nodes to Mobile Users

9. PERFORMANCE EVALUATION

10. They simulate the proposed scheme on QualNet simulator. TTDD: two-tier data dissemination DSM: dynamic sink model

11. PERFORMANCE EVALUATION

14. CONCLUSION The single data gathering tree is constructed to be shared by loosely coupled mobile users. The way about multicasting based on the shared tree propagates collected information to multiple users of the loosely coupled group to reduce communication costs.