Real Time Sensor Networks – challenges and solutions Information Prioritization Proposed scheme:...
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Transcript of Real Time Sensor Networks – challenges and solutions Information Prioritization Proposed scheme:...
Real Time Sensor Networks – challenges and solutions
Information Prioritization
Proposed scheme:• Design techniques for priority assignment to an
information in a mission-specific manner,• Identify a measure of effectiveness (MOE) to evaluate
the prioritization algorithms,• Design and implement algorithms for disseminating
prioritized data,• Evaluate different prioritization algorithms to identify their
strength and limitations, and• Fine-tune the IP stack for an efficient support of
prioritized information dissemination.
Application 2 :• Video Surveillance Application with information prioritization
Sandeep Kakumanu, Rajnish Kumar, Sriram Lakshmanan, Badri Narayanan, Nazanin Rahnavard, Junsuk ShinFaramarz Fekri, Umakishore Ramachandran, Raghupathy Sivakumar
Real Time Sensor Networks
• The primary goal in designing protocols for conventional sensor networks is to optimize energy consumption of the sensors. • Real time sensor networks however are dependent more on timely delivery of data rather than energy constraints. • Applications include multimedia sensor and time critical sensor requirements.
Challenges of Real time sensor networks
Three main challenges of real-time sensor networks• Timeliness• Reliability (Packet level)• Correctness (Application level)
These requirements must be ensured in both the upstream and downstream directions. We work at different layers of the network stack to address these challenges.
SCT
Objective:• Broadcasting in multihop wireless networks
• Energy-Efficient, Reliable, Scalable• Low Complexity: Requires no topology knowledge
Motivation:• Updating software in already deployed sensor/actuator networks• Broadcasting route query packets in reactive routing schemes
Proposed scheme:• CRBcast – a two phase data dissemination algorithm (employing rateless coding) that generalizes probabilistic broadcasting to further reduce the energy costs.
ADV
REQ, i packets
REQ, j packets
DATA, max(i,j) packets
(i) (ii) (iii)
CRBcast
Objective:• Right information at the right time
Motivation:• Moving from a centralized to a distributed solution• Increase Information-Awareness (Cognitive-Awareness)• Information Prioritization and Fidelity Adjustment
Application 1 :• IPTV enhancement using WSN.
Illustration of application scenario
BroadbandConnection
User
User
STB
User
User
STB
STB
STB
TVTV
TV
TV
Sinksensor
Two principles to enhance IPTV :
1. “What you see is what you fetch”
– In cases where there is no active user but the television is on, streams can be sent from server at low priority, low data rate or even paused.
2. “Fetch possible next channel(s) just before the user switches”
– Pre-fetching channels in the background to reduce the user perceived channel switching latency.
Principle:• Use sensor information to prioritize data from high-
bandwidth video cameras.
Details of the applications can be found in the individual posters
Objective:• Aggregate correlated data from different sensors
(homogenous or heterogenous sensors) in order to save bandwidth, reduce latency, reduce energy consumption and provide application level correctness.
Motivation:Two existing approaches for data aggregation: 1. Correlation unaware: Shortest path tree. Does not
maximize the aggregations possible.2. Correlation aware: Steiner Tree. Complex calculations at
individual sensors. Maximal aggregations.• Require efficient aggregation strategy that minimizes
message complexity.Proposed scheme:• SCT (Semantic/Spatial Correlation-aware Tree) – A
distributed coordination scheme that achieves potential cost benefits of efficient aggregation. Can be used for spatial, temporal or semantic correlation of data.