Adaptive Protocols for Information Dissemination in Wireless Sensor Networks 1999

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1 daptive Protocols for Information Dissemination in Wireless Sensor Networks 1999 Joanna Kulik,, Wendi Rabiner,, and Hari Balakrishnan -- MIT Presented by: Isaac Charles Distributing in a Network Why? Fault tolerance ggregation Event recognition State/Programming change based on events Isaac Charles 2005/11/02 2 Dissemination Obstacles Previous pproaches Energy: especially for send Computation: need simple protocols Communication: bandwidth limited Flooding Each node sends to all neighbors Only remember which messages already sent Very simple Many costly sends Isaac Charles 2005/11/02 3 Isaac Charles 2005/11/02 4

2 Previous pproaches Previous pproaches Flooding Each node sends to all neighbors Only remember which messages already sent Very simple Many costly sends Flooding Each node sends to all neighbors Only remember which messages already sent Very simple Many costly sends Duplicate Duplicate Isaac Charles 2005/11/02 5 Isaac Charles 2005/11/02 6 Gossiping Each recipient sends to one neighbor Path is random Low incremental energy Long delay to Gossiping Each recipient sends to one neighbor Path is random Low incremental energy Long delay to Isaac Charles 2005/11/02 7 Isaac Charles 2005/11/02 8

3 Gossiping Each recipient sends to one neighbor Path is random Low incremental energy Long delay to Gossiping Each recipient sends to one neighbor Path is random Low incremental energy Long delay to Duplicate Isaac Charles 2005/11/02 9 Isaac Charles 2005/11/02 10 Ideal Flood, but each node only receives data once Would require full network knowledge Best possible energy Fastest possible Ideal Flood, but each node only receives data once Would require full network knowledge Best possible energy Fastest possible Isaac Charles 2005/11/02 11 Isaac Charles 2005/11/02 12

4 Ideal Flood, but each node only receives data once Would require full network knowledge Best possible energy Fastest possible Implosion Problems with Previous pproaches Isaac Charles 2005/11/02 13 Isaac Charles 2005/11/02 14 Implosion Overlap Problems with Previous pproaches Implosion Overlap Resource blindness Problems with Previous pproaches Isaac Charles 2005/11/02 15 Isaac Charles 2005/11/02 16

5 SPIN Sensor Protocols for Information via Negotiation Variation on flooding Intended to reduce energy usage Key items: Negotiation Resource adaptation Negotiation Transmit only useful data packets Meta-data: unique identifiers for data llows nodes to know what data is offered Eliminates implosion and overlap pplication-specific in SPIN Possible examples: Node s s name (x, y, Φ) ) for a camera Isaac Charles 2005/11/02 17 Isaac Charles 2005/11/ Protocol Steps: DV advertise available data REQ request some advertised data DT send data requested Event Isaac Charles 2005/11/02 19 Isaac Charles 2005/11/02 20

6 DV DV REQ Isaac Charles 2005/11/02 21 Isaac Charles 2005/11/02 22 DT DV DV DV DV Isaac Charles 2005/11/02 23 Isaac Charles 2005/11/02 24

7 REQ REQ REQ DT DT DT Isaac Charles 2005/11/02 25 Isaac Charles 2005/11/ dvantages Meta-data small and cheap Do not send full data unless requested Simple protocol Neighbors only no routing tables No per-neighbor state Isaac Charles 2005/11/02 27 Isaac Charles 2005/11/02 28

8 SPIN-2 2 Improvements Resource daptation Scales back node participation Step 1: Stop forwarding Step 2: Stop requesting Still receives DV and REQ Provides resource-management interface to application Helps resolve resource blindness Simulation had: No packet loss No queuing delays 25 nodes Simulated Results Isaac Charles 2005/11/02 29 Isaac Charles 2005/11/02 30 Flooding almost ideal SPIN only a constant factor (80 ms) slower Diff is DV/ REQ overhead Experiment 1: Rate of Convergence Experiment 1: Rate of Energy Usage Flooding 3.5X more redundant packets SPIN near ideal SPIN: 53% redundant, but only metadata Isaac Charles 2005/11/02 31 Isaac Charles 2005/11/02 32

9 Experiment 2: Limited Energy System energy limited, not by node Results: Flooding 53% 68% SPIN-2 73% Ideal 85% Conclusion SPIN solves implosion & overlap Simple protocol, no per-neighbor state Comparable to flooding in terms of time 75% energy reduction over flooding Not ideal, but rarely far SPIN-2 2 helps reduce energy consumption Isaac Charles 2005/11/02 33 Isaac Charles 2005/11/02 34 Future Research djust for lossy networks? Periodically re-dv? Re-REQ REQ or resend DT if no response? How to adjust for mobile networks? Queue/processing delay analysis How to better avoid partitioning? Better energy decisions/options Questions? Isaac Charles 2005/11/02 35 Isaac Charles 2005/11/02 36