Prepared By:

Syed Tazirul Ilm.

M.Tech (3rd Sem)

Roll No: 140320007016

GIMT,Guwahati

15 October 2015

Assam Science & Technology University (ASTU).

A Project Review On

Survey Of Routing In Wireless Sensor Network.

(WSN)

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A Brief Introduction On WSN.

Components Of WSN.

Applications Of WSN.

Difference between WSN & MANET.

WSN Challenges.

WSN Routing Challenges.

WSN Routing Protocols

References .

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• Each sensor node is called as Mote. • WSN is self organizing so deletion/addition of node is easier. • Each mote communicate to Sink Node either through:

Single Hop Interaction. Multi Hop Interaction.

• The Sink Node(BS) is connected to the Base Station(BS). • The BS is connected to the internet.

SO,

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Mote 4

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• Sensor nodes are densely deployed.

• Sensor nodes are prone to failures. • WSN broadcast but ad hoc is point-to

point.

• Sensor node are limited in power computation capacities and memory.

• Sensor nodes may not have global identification.

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The Applications Of WSN is mainly classified as: Monitoring Space: Habitat Monitoring. Electronic Surveillance. Domotics (Home Automation.)

Monitoring Targets: Medical Diagnostics. War Field & Military. NBC(Nuclear Biological Chemical) attack. Industrial Equipment Maintenance.

Hybrid WSN: To control the interaction between Targets & the surrounding environment.

Emergency Management eg. Recovering After Disaster.

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Single Hop Network Architecture.

Multi Hop Network Architecture: In multi hop communication, a sensor node transmits its sensed data toward the sink via one or more intermediate nodes, which can reduce the energy consumption for communication.

Can be categorized into Flat Architecture. Hierarchical Architecture.

Sink Node

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Flat Architecture: In a flat network, each node plays the same role in performing a sensing task and all sensor nodes are peers. Due to the large number of sensor nodes, it is not feasible to assign a global identifier to each node in a sensor network. (Fig 1)

Sink Node

Hierarchical Architecture: In a hierarchical network, sensor nodes are organized into clusters, where the cluster members send their data to the cluster heads while the cluster heads serve as relays for transmitting the data to the sink. (Fig 2)

Fig 1: Fig 2:

Cluster Head

Cluster Member

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• Reliability: Since messages travel multiple hops it is important to have a high reliability on each link , otherwise the probability of a message transmitting over the entire network would be unacceptably low.

• Integration with wake/sleep schedules: To save power many WSN place nodes into sleep states. Obviously, an awake node should not choose an asleep node as the next hop.

• Voids: Since WSN nodes have a limited transmission range, it is

possible that for some node in the routing path there are no forwarding nodes in the direction a message is supposed to travel.

• Congestion: WSN traffic are periodic and infrequent, so congestion is not an issue until a more demanding WSN is required, but congestion in BS exist.

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Traditional technique Flooding. Gossiping.

Current routing technique Data Centric Routing. Hierarchical-routing. Location-based routing

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In flooding, each sensor receiving a data packet broadcasts it to all of its neighbors and this process continues until the packet arrives at the destination or the maximum number of hops for the packet is reached.

Disadvantages: •Implosion (Duplicate Data). •Overlap

On the other hand, gossiping is a slightly enhanced version of flooding where the receiving node sends the packet to a randomly selected neighbor, which picks another random neighbor to forward the packet to and so on.

Disadvantage: Delay Transmission. Advantage: Avoid Implosion.

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Disadvantage of Flooding

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Data Centric Routing routing(1/6): In data-centric routing protocols, when the source sensors

send their data to the sink, intermediate sensors can perform some form of aggregation on the data originating from multiple source sensors and send the aggregated data toward the sink. This process can result in energy savings because of less transmission required to send the data from the sources to the sink.

Some of this popular Protocols are: SPIN (Sensor Protocol for Information via Negotiation).

DD (Directed diffusion).

Rumor routing.

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SPIN(1/2)[1]

It assign a high-level name to completely describe

their collected data (called meta-data).

Use thee types of messages ADV (advertisement),

REQ (request) and DATA. • Topological changes are localized. • Advantage: provides more energy savings than

flooding, and metadata negotiation almost halves the redundant data.

• Drawback: SPIN’s data advertisement mechanism cannot guarantee delivery of data.

[1]W. Heinzelman, J. Kulik, and H. Balakrishnan, “Adaptive Protocols for Information Dissemination in Wireless Sensor Networks,” Proc. 5thACM/IEEE Mobicom, Seattle, WA, Aug. 1999. pp. 174–85.

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SPIN(2/2)

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Directed Diffusion(1/2)[1]

It’s Accomplished by:

Propagate interest.

Set up gradients.

Send data and path reinforcement.

Directed diffusion differs from SPIN in two aspects. Query method. Communication method.

Directed diffusion may not be applied to applications (e.g., environmental monitoring)

• Matching data to queries might require some extra overhead

[1]C. Intanagonwiwat, R. Govindan, and D. Estrin, “Directed Diffusion: a Scalable and Robust Communication Paradigm for Sensor Networks,” Proc. ACM Mobi- Com 2000, Boston, MA, 2000, pp.56–67.

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DD(2/2)

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Rumor routing[1] • A variation of directed diffusion.

• Use an events table and a agent.

• The number of events is small and the number of queries is large

[1]D. Braginsky and D. Estrin, “Rumor Routing Algorithm for Sensor Networks,” Proc. 1st Wksp. Sensor Networks and Apps., Atlanta, GA, Oct. 2002.

Hierarchical-routing: Clustering is an energy-efficient communication

protocol that can be used by the sensors to report their sensed data to the sink.

Protocols are:

• LEACH (Low Energy Adaptive Clustering Hierarchy)

• PEGASIS (Power-Efficient Gathering in Sensor Information Systems)

• TEEN(APTEEN) (Threshold-Sensitive Energy Efficient Protocols)

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LEACH(1/2)

Low-energy adaptive clustering hierarchy (LEACH) is one of the most popular hierarchical routing algorithms for sensor networks.

The idea is to form clusters of the sensor nodes based on the received signal strength and use local cluster heads as routers to the sink.

Cluster heads change randomly over time in order to balance the energy dissipation of nodes.

LEACH uses single-hop routing where each node can transmit directly to the cluster-head and the sink.

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LEACH(2/2)

Drawbacks It is not applicable to networks deployed in large

regions The idea of dynamic clustering brings extra overhead The protocol assumes that all nodes begin with the

same amount of energy capacity in each election round.

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Comparison between SPIN,LEACH and directed diffusion[1]

[1]W. Heinzelman, A. Chandrakasan and H. Balakrishnan, “Energy-Efficient Communication Protocol for Wireless Microsensor Networks,” Proc. 33rd Hawaii Int’l. Conf. Sys. Sci., Jan. 2000. 25

PEGASIS

Power-efficient GAthering in Sensor Information Systems (PEGASIS) is an improvement of the LEACH protocol.

Rather than forming multiple clusters, PEGASIS forms chains from sensor nodes so that each node transmits and receives from a neighbor and only one node is selected from that chain to transmit to the base station (sink).

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Comparison between PEGASIS and SPIN

PEGASIS save energy in several stages:

In the local gathering , the distance that node transmit

The amount of data for head to receive

Only one node transmits to BS

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TEEN and APTEEN(1/3)

• Threshold sensitive Energy Efficient sensor Network protocol (TEEN) is a hierarchical protocol designed to be responsive to sudden changes in the sensed attributes such as temperature.

• TEEN pursues a hierarchical approach along with the use of a data-centric mechanism.

• The sensor network architecture is based on a hierarchical grouping where closer nodes form clusters and this process goes on the second level until base station (sink) is reached.

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TEEN and APTEEN(2/3) (con.)

After the clusters are formed, the cluster head broadcasts two thresholds to the nodes. These are hard and soft thresholds for sensed attributes.

Hard threshold is the minimum possible value of an attribute to trigger a sensor node to switch on its transmitter and transmit to the cluster head.

Once a node senses a value at or beyond the hard threshold, it transmits data only when the value of that attribute changes by an amount equal to or greater than the soft threshold.

However, TEEN is not good for applications where periodic reports are needed since the user may not get any data at all if the thresholds are not reached.

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TEEN and APTEEN (3/3)(con.)

• The Adaptive Threshold sensitive Energy Efficient sensor Network protocol (APTEEN) aims at both capturing periodic data collections and reacting to time-critical events.

• APTEEN supports three different query types:

• historical, to analyze past data values.

• one-time, to take a snapshot view of the network.

• persistent to monitor an event for a period of time.

• The main drawbacks of the two approaches are the overhead and complexity of forming clusters in multiple levels, implementing threshold-based functions and dealing with attribute-based naming of queries.

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Location-based routing

In location-based protocols, sensor nodes are addressed by means of their locations. Location information for sensor nodes is required for sensor networks by most of the routing protocols to calculate the distance between two particular nodes so that energy consumption can be estimated. Protocols are:

• GEAR (Geographic and Energy Aware Routing)

• GAF

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GAF

GAF ( Geographic adaptive fidelity ) conserves energy by turning off unnecessary nodes in the network without affecting the level of routing fidelity.

It forms a virtual grid for the covered area. Each node uses its GPS-indicated location to associate itself with a point in the virtual grid.

Nodes associated with the same point on the grid are considered equivalent in terms of the cost of packet routing.

There are three states defined in GAF.

discovery for determining the neighbors in the grid

active reflecting participation in routing

sleep when the radio is turned off

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GAF(1/2) (con.)

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GAF (2/2)(con.)

In order to handle the mobility, each node in the grid estimates its leaving time of grid and sends this to its neighbors.

The sleeping neighbors adjust their sleeping time accordingly in order to keep the routing fidelity.

Although GAF is a location-based protocol, it may also be considered as a hierarchical protocol, where the clusters are based on geographic location.

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GEAR(1/2)

The protocol, namely geographic and energy-aware routing (GEAR), uses energy aware and geographically informed neighbor selection heuristics to route a packet towards the target region.

In GEAR, each node keeps an estimated cost and a learning cost of reaching the destination through its neighbors.

The estimated cost is a combination of residual energy and distance to destination.

The learned cost is a refinement of the estimated cost that accounts for routing around holes in the network.

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GEAR(2/2) (con.)

• A hole occurs when a node does not have any closer neighbor to the target region than itself.

• There are two phases in the algorithm:

• Forwarding packets towards the target region: • Upon receiving a packet, a node checks its neighbors to see if

there is one neighbor, which is closer to the target region than itself.

• Forwarding the packets within the region: • If the packet has reached the region, it can be diffused in that

region by either recursive geographic forwarding or restricted flooding.

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