TTDD: A Two-tier Data Dissemination Model for Large- scale Wireless Sensor Networks Haiyun Luo, Fan Ye, Jerry Cheng, Songwu Lu, Lixia Zhang (UCLA) Mobicom 2002 Bao-Hua Yang
Outline Introduction Two-tier data dissemination Performance evaluation Conclusion
Introduction
Stimulus Sink Assumption: Stimulus/sink: mobile, multiple Sensor node: stationary, with GPS
Introduction --- Basic idea Stimulus Sink Protocol Architecture 1.Grid construction 2.Two-Tier query and data forwarding 3.Grid maintenance α
Two-Tier data dissemination --- Grid construction source
Two-Tier data dissemination --- Grid construction α data announcement will stop at a node that is closer to Lp than all its neighbors Source send “ data announcement ” using greedy geographical forwarding Source location, Lp, Grid lifetime Dissemination node
Two-Tier data dissemination --- Grid construction α Data announcement L P Upstream dissemination node
Two-Tier data dissemination --- Grid construction α
α
Two-Tier data dissemination --- Two-Tier query and data forwarding α
Primary Agent Immediate dissemination node
Two-Tier data dissemination --- Two-Tier query and data forwarding α
α
α
α
PA Immediate agent
Two-Tier data dissemination --- Two-Tier query and data forwarding PA IA
Two-Tier data dissemination --- Grid maintenance Two way to maintain the grid “ Grid lifetime ” in data announcement Dissemination node fails “ upstream information duplication ” mechanism
Two-Tier data dissemination --- Grid maintenance α
α
Performance Evaluation Simulator: ns-2 Parameter: Sink: 4 Source: 4 Sensor node: 200 Sensing range: 2000*2000 m 2 Simulation time: 200 second Cell size: 600 meters
Performance Evaluation
Conclusion TTDD: two-tier data dissemination Model Construct & maintain a grid structure with low overhead Can effectively deliver data from multiple sources to multiple mobile sinks