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Broadening the Concept of Aggregation in Wireless Sensor Networks. Eli De Poorter , Stefan Bouckaert , Ingrid Moerman , Piet Demeester IBCN: INTEC Broadband Communication Networks IBBT – INTEC – Ghent University - Belgium. Goals. Overview. Why aggregation? Overview of current techniques
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Broadening the Concept of Aggregation in Wireless Sensor Networks Eli De Poorter, Stefan Bouckaert, Ingrid Moerman, Piet DemeesterIBCN: INTEC Broadband Communication NetworksIBBT – INTEC – Ghent University - Belgium Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
Goals Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
Overview • Why aggregation? • Overview of current techniques • Broadening the concept of aggregation • Classification of aggregation approaches • Example architecture • Conclusions and suggestions Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
Why aggregation? • Most energy is consumed when packets are transmitted RADIO 20 15 10 Power (mW) 5 0 SENSOR CPU RX TX IDLE SLEEP • aggregation techniques are used to combine the measured data from different nodes into a single transmission Sensorcomm 2008
What aboutarchitectural support? Can we do more? Sensorcomm 2008
Overview • Why aggregation? • Overview of current techniques • Broadening the concept of aggregation • Classification of aggregation approaches • Example architecture • Conclusions and suggestions Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
existing techniques Data aggregation (WSN) Packet combination (WLAN) Measured data from different sources is processed and combined in an intermediate node Packet frames destined to one-hop neighbors are sent in one burst or combined into one packet • tied to the routing or clustering protocol • application data is aggregated • efficient aggregation function for reduction of the data size • often multi-hop coordination • tied to the PHY or MAC protocol • packets of any kind are combined • packet are not inspected nor processed • mostly limited to single-hop neighbors Sensorcomm 2008
Examples Data aggregation (WSN) Packet combination (WLAN) MAC layer aggregation Clustering based aggregation data 1 • data 2 • data 1 • data 2 PHY aggregation Routing (tree) based aggregation data 1 • data 2 • data 1 • data 2 MAC header PHY header Sensorcomm 2008
Overview • Introduction • Overview of current techniques • Broadening the concept of aggregation • Classification of aggregation approaches • Example architecture • Conclusions and suggestions Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
Global aggregation Global aggregation covers all methodologies that offer architecturalsupportfor the intelligent gathering, combining and processing of information from any information source in a node or network. Main objective: reduce transmissions, increase network lifetime Sensorcomm 2008
Global aggregation: features Global aggregation Packet combination Data aggregation • Supports all types of information exchanges • Use efficient fusion functions • Support single-hop aggregation • Support multi-hop aggregation • Provide architectural support for aggregation • Not tied to a fixed protocol • Support QoS Sensorcomm 2008
Overview • Why aggregation? • Overview of current techniques • Broadening the concept of aggregation • Classification of aggregation approaches • Example architecture • Conclusions and suggestions Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
Classification • Based on the aggregation techniques • packet combination vs. packet fusion • information merging • duplicate sensitive vs. duplicate insensitive • deterministic vs. stochastic • Based on the networking type • single-hop aggregation • multi-hop aggregation • Standardization of information representation • e.g. signal quality, remaining energy, node role,… • fewer exchanges required • always up-to-date • more easy interworking between protocols Sensorcomm 2008
Overview • Why aggregation? • Overview of current techniques • Broadening the concept of aggregation • Classification of aggregation approaches • Example architecture • Conclusions and suggestions Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
simple example architecture • single hop, deterministic, information fusing, duplicate sensitive aggregation scheme enabled node Traditional system Architectural aggregation Application Packet Forwarding Classifier (Destination) Packet Forwarding priority Protocol 1 SubscribingApplication Parameter Space Waiting Space … Subscribing Protocol 1 Queue Protocolk Subscribing Protocol k PacketOUT PacketOUT (b) (a) Sensorcomm 2008
Realistic scenario Without aggregation 0 60 120 180 0 75 225 150 4 MAC protocol packets are sent 4 routing protocol packets are sent Sensorcomm 2008
Realistic scenario Using aggregation 0 60 120 180 30s 30s 30s 0 75 225 150 4 MAC protocol packets are sent 3 routing protocol packets are sent Sensorcomm 2008
Example architecture - advantages Sensorcomm 2008
Example architecture • in paper: mathematical evaluation Sensorcomm 2008
Realistic scenario Sensorcomm 2008
Overview • Why aggregation? • Overview of current techniques • Broadening the concept of aggregation • Classification of aggregation approaches • Example architecture • Conclusions and suggestions Sensorcomm 2008 - Broadening the Concept of Aggregation in Wireless Sensor Networks
Conclusions • By broadening the concept of aggregation, many transmissions can be saved • Global aggregation methods should include: • An architectural design to ensure protocol independence • Aggregation of both data and control messages • Standardization efforts for data representation • Several ideas in the paper, further research is necessary Sensorcomm 2008
Interesting research approaches • multi-hop aggregation • using a separate control plane • using the available routing protocol • Adaptive aggregation approaches, based on the situation • Tree based vs. clustering • Calculation of optimal packet sizes • Aggregation with advanced QoS support • example: what if 2 streams with diferent QoS characteristics are aggregated? • Analysis of relation between packet savings and network lifetime • Influence of aggregation on existing network protocols Sensorcomm 2008
Thank you! Eli.Depoorter@intec.ugent.bewww.ibcn.intec.ugent.bewww.IBBT.be Sensorcomm 2008