12-10-2012, 04:47 PM
Routing Techniques in Wireless Sensor Networks
Routing Techniques.pptx (Size: 1.35 MB / Downloads: 23)
Routing
Routing is a key responsibility of the network layer
Routing Protocol is responsible for finding and maintaining path from sensor to sink.
Routing protocols for Wireless Sensor Networks
The Main Goal of WSNS for Routing Protocols
Routing Metrics
Network Layer Responsibility
Flooding
Data Centric Routing
Proactive Routing
On-Demand Routing
Hierarchical Routing
Location Based Routing
QoS-Based Routing
Goal of WSNs Routing Protocols
To Develop Energy efficient routing strategies to transfer sensor data from nodes to sinks for the purpose of maximizing the lifetime of WSNS
Network Layer Responsibilities
Direct Communication model:- Energy sensors communicates directly(single hop) with the sink device(base station)
Multi-hop communication model:- sensors co-operate in propagating sensor data towards the sink
Protocol Operation:-
Negotiation Based: Data transfers before they occur
Multipath: Use multiple routes simultaneously
Query-Based: Receiver-initiated
QoS-Based: Satisfy certain QoS Constraints
Coherent-Based: Perform only minimum amount of in Network processing
Flooding and Gossiping
Flooding:-
Every sensor (re-)broadcasts sensor data to all of its neighbors
Sensor broadcasts every packet it receives
Relay of packet till the destination or maximum no of hops
No topology maintenance or routing
Gossiping:-
Enhanced version of flooding
Sends received packet to a randomly selected neighbor
Directed Diffusion
Data-Centric and application-aware dissemination protocol
Nodes request data by sending interests for named data(data is named by attribute-value pairs)
Interest dissemination sets up gradients within network to direct sensor data toward recipient
Intermediate nodes along the paths can combine data from different sources
Eliminates redundancy
Reduce number of transmissions
Interest node(sink) periodically sends interests to neighbors, which re-broadcast these messages(a)
Each node establishes a gradient towards the sink, which is a reply link toward the neighbor from which the interest was received(b)
Source can send data towards sink using these gradients©
Rumor Routing
Variation of Directed Diffusion
Flood the events instead of the queries
Creation of an event->generation of a long live packet travel through the network(agent)
Nodes save the event in a local table
When a node receives query->checks its table and returns source-destination path
Advantages:-
Can handle node failure
Significant Energy savings
Disadvantages:-
Works well only with small number of events
Overhead through adjusting parameters, like the time to live of the agent
Gradient-Based Routing(GBR)
Slightly changed version of Directed Diffusion
Keep the number of hops to the sink when an interest is created(height of the node)
Node's height-neighbors height = gradient of the link
Node forward packet to the link with largest gradient
Traffic spreading and Data Aggregation Balance Uniformly the network traffic
Stochastic scheme
Energy-based-scheme
Stream-based-scheme
Outperforms Directed Diffusion in terms of total communication Energy