fusion-oriented sensor networking : network architectures, communication protocols, and routing...
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Fusion-Oriented Sensor Networking :
Network Architectures, Communication Protocols, and
Routing Algorithms
Dr. Wei Chen
An Example of Sensor Network
Mathematical Model for communication Networks
Directed Graph G=(V,E)
V={nodes}
E={edge (u,v): if node u
can transmit data to node v}
Nodes with different communication range
• Broadcasting using flooding
Source
How to solve collision problem?
-- Randomized algorithm
(generate a random number k, 0<k<d, transmit data at kth time slot)
• How to decide d?
• It may need long time in a dense network !!!
Communication Efficiency
(Each node keeps a neighbor list in G)
Example: Broadcasting in G=(V,E)
Broadcasting using Euclidean Circle
Source
(Each node keeps a neighbor list in T)
How to solve collision problem?
• Deterministic algorithm: only one node transmits in one time slot.
• Communication complexity: Totally 2(n-1) time slots with n nodes
It is expensive in a large scale of network!!!
• Forming a spanning tree T
• Transmitting data in depth-first style
Cluster-Based Network Architecture
• Unstructured sensor network
• Cluster-based Architecture
– Network is self-organized to separated clusters.
– Each cluster has one head which connected to its members.
– Clusters are connected by gateway nodes.
– Communication is inefficient– Difficult to embed different levels of
data fusion
Example: Broadcasting on cluster-based network
s
• Deterministic algorithm
• Communication complexity: 2(Number of clusters)
Communication Protocols
Backbone communication corresponding to high level data fusion
Local Communication corresponding to lower level data fusion
What does each node have to keep?
• Member node: its head id
• Head node: list of its member id
• Head/gateway node: list of its neighbor id on backbone
Backbone communicationLocal Communication
Communication Protocols (Continue)
More Consideration
• Assigning a different channel to backbone communication.
• Using randomized accessing for local communication, and using deterministic accessing with Euclidean circle for backbone communication.
S
D
Routing AlgorithmsFundamental communication tasks
• Broadcasting, Multi-casting, Peer-peer communication, ….
Example: peer-peer communication
Network Reconfiguration
Operations for Reconfiguration• Node move-in• Node move-out
Problem:
• A node is going to die (lower battery)
• A node is going to join (after charging)
Node move-in algorithms
Want to join
Node move-in algorithms
Want to join
Clustering structure on Multi-types of sensor nodes
Sink
Highway (Back bone)
Local way (cluster)
Primary sensor node
Communicable sensor node
Embedded Protocols/Algorithms
Hierarchical Communication/routing protocols
Highest Level
Physical Layer (unstructured Communication Network)
Fusion-Oriented Application Layer
Lowest Level
Communication Tasks
Multicasting
Broadcasting Global SynchronizationNetwork Maintenance Tasks
Network Reconfiguration
Structured (Hierarchical) Communication Network
Static/Dynamic Grained-Clustering
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