Routing Techniques in WSN- A survey-Part 4

GAF: Represents Gepgraphic ad aptive fidelity. In this protocol, Nodes already know thier location through GPS. Network is divided into grids. Set of nodes are assigned a grid, and optimize the sleep and active times w/out affecting routing fidelity and in this way energy is conserved therby increasing the n/w lifetime.

GEAR: Uses geographic attributes from data to route packets towards destinationinstead of using whole network. Learning and estimated costs are associated with each node and a hole is created in the region when node doesn't have a neighbor closer to target other than itself. Protocol consosts of two phases: Forwarding packet towards target region and Forwarding packet within region.

GOAFR: Its a combination of greedy and face roting algorithms.Greedy algorithm doesn't work best for non dense n/w's and OFR aims to find best node in n/w closer to destination.Thus by combining both of these algorithms it becomes optimal for both worst and average case efficiency.

SPAN: It selects nodes as coordinators based on position.Node becomes a coordinator if 2 neighbors can't reach each other directly.

Multipath routing protocol:It encourages the use of multiple path rather one single path.Introduced approach is to use path with highest residual energy until the energy falls below back up path after which back up path is used. In this way energy resources are maintained for long n/w lifetime.

Query based and Negotiation based routing:In query based, destination node sends query through network. Once the query is matched, node with data sends it to destination node.
Negotiation based routing uses high level data descriptors that eliminate redundant data transmission through negotiation.

Non coherent processing: Nodes will locally process raw data before being sent to other nodes for further processing. Consists of three phases: Target detection,Data collection and preprocessing,Memebership declaration and Central node election.

Coherent data processing: Data is forwarded to aggragators after min processing like time stamping, duplicate suppression.Also it is selected to perform energy efficient routing.