IN-NETWORK VS CENTRALIZED PROCESSING FOR LIGHT DETECTION SYSTEM USING WIRELESS SENSOR NETWORKS Presentation by, Desai, Bhairav Solanki, Arpan

Outline  Introduction  Algorithm and Methodology  Formation of routing topology  In-network aggregation  Centralized aggregation  Experiments and Results  Conclusion  References

Introduction

Databases Vs Sensor Networks  Range Queries – much better idea for sensor networks  Additional operators have to be added for Query Language e.g. epoch and duration  Continuous long running Queries

Data Centric Networking  Combination of Querying, storage and routing techniques  Works efficiently if we use the combination as application specific rather than generalized like traditional IP based techniques.

Challenges  Volatile System  Append Only Streams  High Energy cost of communication  Variable data arrival rate at different nodes  Limited Storage on nodes

Centralized Processing

In Network Processing

Objective  Implementing In-network aggregation in real environment for a Data-centric application  Comparing In-network and Centralized aggregation approach

Algorithm and Methodology

Topology Formation  Collection Tree Protocol  Base Station – Root of the Collection Tree  EXT node = EXT parent + EXT link to parent where EXT root = 0  Detecting Routing Loops

In-network Aggregation  Data aggregation at in-network nodes  Steps required to overcome change in topology

Network Behavior

Two phases  Node discovery phase  Discovery of topology  Assigning time interval  Aggregation phase  Sense  Aggregate  Forward

Assigning time interval

Calculate time interval Where T node – Time duration of a node D – Total depth of the tree L node – Level of the node in the routing tree T – Total epoch duration

Processing Plans (a) Sensing leaf node (b) Non-sensing intermediate node (c) Sensing intermediate node

Node Operation (Sensing leaf nodes)

Node Operation (Sensing intermediate nodes)

Node Operation (Non-sensing intermediate nodes)

Nodes divided in groups

Change in topology

Consequences Before Node 20 30 Parent 11 2 32 31 Causes change in depth of the tree Level 3 2 3 Parent 1 3 33 After Level 2 2 4 That’s why topology reformation is required

Centralized Aggregation  No discovery of topology  No assignment of time interval  No steps to overcome change in topology  Aggregation of data at the base-station

Node Operation (Sensing leaf nodes)

Node Operation (Sensing intermediate nodes)

Node Operation (Non-sensing intermediate nodes)

Job of the base station  Collect data from all the nodes  Perform aggregation

Experiments and Results

In-network aggregation

In-network aggregation

In-network aggregation

In-network aggregation

In-network aggregation

In-network aggregation

Centralized aggregation

Comparing both approaches

Comparing Bytes Transmitted

Conclusion  Lesser number of Hop counts  Low amount of bytes transmitted  Lower energy consumption

References       C. Intanagonwiwat, R. Govindan, and D. Estrin, Directed Diffusion: A Scalable and Robust Communication Paradigm for Sensor Networks,

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References          J. Bonfils and P. Bonnet, Adaptive and Decentralized Operator Placement for In-Network Query Processing, Telecommunication Systems - Special Issue on Wireless Sensor Networks, January 2004 S. Madden, M.J. Franklin, J.M. Hellerstein, and W. Hong, TAG: a Tiny AGgregation Service for Ad-Hoc Sensor Networks, 5th Symposium on Operating System Design and Implementation (OSDI 2002), December 2002 Y. Yao and J. Gehrke, The cougar Approach to In-Network Query Processing in Sensor Networks, SIGMOD, March 2002 S. Madden, R. Szewczyk, M.J. Franklin, and D. Culler, Supporting Aggregate Queries Over Ad Hoc Wireless Sensor Networks, Mobile Computing Systems and Applications, June 2002 S. Ganeriwal, R. Kumar, and M. B. Srivastava, Timing-Sync Protocol for Sensor Networks, Proceedings of ACM SenSys’03, November 2003 TinyOS Mailing list, http://www.tinyos.net/ TinyOS Naming Conventions, http://www.tinyos.net/tinyos-1.x/doc/tutorial/naming.html

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