Wireless Multimedia Sensor Networks

Real-time Multimedia Monitoring in
Large-Scale Wireless Multimedia Sensor
Networks: Research Challenges
Joint work by:
M.Cesana, A.Redondi – Politecnico di Milano
N. Tiglao, A. Grilo – INESC-ID/INOV/IST
J. M. Barcelo-Ordinas, M. Alaei – Universitat Politecnica de Catalunya
P. Todorova – Fraunhofer FOKUS

MWMSN Project

 Multi-tier Wireless Multimedia Sensor
Networks
 Goal: To enable support for enhanced
monitoring and tracking applications through
multimedia visual/audio wireless sensor nodes

NGI 2012, Karlskrona, Sweden 2

Outline

 Introduction
 Real-time multimedia monitoring applications
 Efficient delivery of visual data in WMSNs
 MAC Layer
 Network Layer
 Transport Layer
 Research challenges and final discussion


Introduction
 WSN equipped with multimedia sensors give
birth to WMSN.

 They enable a new class of monitoring
applications, but demanding in terms of:
 computational resources
 energy resources

 Need for innovative solutions:
 combination/optimization techniques at
the different layers of the protocol stack

Real-Time Multimedia Monitoring

 Supervised monitoring (Image/Video-based)
 Delivery of compressed image/video flows,
analyzed by a human operator

 Low bitrate achievable with complex encoders
(e.g. H.264/AVC), not supported by WMSN

 Suitable solutions: Object-based approaches,
Distributed Video Coding

 Challenge: Successful implementation of these
techniques

Real-Time Multimedia Monitoring

 Unsupervised monitoring (Feature-based)
 Use visual features to describe the underlying pixel
content

 Suitable for a broad range of monitoring tasks
(e.g., object recognition, face detection…)

 Main challenges:
 Coding of visual features
 Low-complexity feature extraction algorithms
 Rate-accuracy models for resources allocation


MAC Layer

 Main requirements for video streaming
over WMSN:
 Steady-flow of information
 Delay-bounded delivery of packets

 As a consequence, the MAC layer has to:
 support reliable communication
 be QoS-aware
 save as much energy as possible


MAC Layer – available solutions

 Available solutions to tune QoS metrics:
 Power control
 Traffic class differentiation (Q-MAC)
 Contention-free vs. contention-based approaches
 Duty-cycling control
 Queuing and scheduling mechanisms
 Error control mechanisms

 For WMSN, most important features are:
 Intra/Inter-node traffic class differentiation
 Node synchronization (duty-cycling control)


MAC Layer – available solutions


Network Layer: Routing
 Traditional solutions for WSN focused on energy
consumption
 In the WMSN case, need also for real-time
delivery
 Desirable features
 Traffic differentiation and joint-optimization of
multiple QoS goals
 Resource balancing
 Fast adaptation to change in monitoring conditions
 Support to in-network processing / cross-layer opt.
 Scalability
 Energy-harvesting awareness

Network Layer – available solutions


Transport Layer
 Similarly to the network layer case, available
solutions are not suitable for WMSN.

 Design guidelines
 Differentiated reliability
 Trade-off between reliability/timeliness
 Media-centric collaborative reliability
 Congestion control
 Cross-layer optimization


Transport Layer – available solutions


Collaborative Sensing in WMSN
 Multimedia nodes are characterized by a
directional sensing model (FoV)

 They can be grouped basing on their common
sensing coverage

 Several challenges
 Directional coverage
 Clustering / Scheduling
 Collaboration protocols


Conclusions and Research Challenges
 Application Layer (feature-based):
 Novel coding techniques
 Practical implementations
 MAC Layer
 Service differentiation
 Dynamic duty-cycling control
 Network Layer:
 In-network processing
 Energy harvesting
 Transport Layer
 Media-centric reliability
 Cross-layer optimization with routing

Thank your for your attention!


Project Members
 M. Cesana, A. Redondi – {cesana,
redondi}@elet.polimi.it
 Multimedia coding, Application
 N. Tiglao, A. Grilo – {nestor.tiglao,
antonio.grilo}@inesc-id.pt
 Routing and Transport
 J. M. Barcelo-Ordinas, M. Alaei –
{joseb,malaei}@ac.upc.edu
 MAC Layer
 P. Todorova –
petia.todorova@fokus.fraunhofer.de
 Collaborative Sensing

Wireless Multimedia Sensor Networks

More Related Content

What's hot (20)

Viewers also liked (18)

Similar to Wireless Multimedia Sensor Networks (20)

More from Nestor Michael Tiglao (7)

Recently uploaded (20)

Wireless Multimedia Sensor Networks