Routing strategies in DTN for localization application using

WSN nodes

Contents Introduction Literature Review Aim & Objectives of Dissertation Problem Formulation Results Conclusions Future Work References

Introduction

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What is WSN ? WIRELESS Sensor Networks (WSNs) consist of large number of

sensor nodes it can be stationary or mobile. Deployed either inside or very close to the sensed phenomenon where each node has capability to sense data, process the data and communicating with each other by means of wireless network.

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Operational challenges of WSN Don’t have fixed infrastructure

Dynamic network topology

Limited energy storage

Computational and memory resources

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What is DTN ? Networks (DTNs) have the potential to interconnect

devices in regions that current networking technology cannot reach.

The idea is that an end-to-end connection may never be present.

Intermediate nodes take custody of the data being transferred and forward it as the opportunity arises.

Conventional routing protocols fail (e.g. DSR, AODV, DSDV)

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What is DTN ? A Delay Tolerant Network (DTN) is defined as a network that

suffers from:• Network Partitioning• Network Interruptions, Failures and Heterogeneity• Asymmetric, Long and Variable Data-Rates• Energy, Bandwidth, Buffer and Cost Restrictions

Idea: Store-Carry-and-Forward

Literature review

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Routing in Delay Tolerant Network

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classified according to two key properties:

I Routing based on knowledge:

Epidemic Routing

PROPHET (Probabilistic)

Spray and Wait

MAXPROP

II Routing based on additional nodes:

Data Mule

Message Ferry

Throwboxes

Epidemic Routing

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Author : Vahdat and Becker - 2000

Goal : Maximize message delivery rate

Concept : Floods messages into the network

Advantages:

High delivery ratio

Disadvantages:

Needs infinite buffer space

High overhead

PROPHET

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Author : Anders Lindgren -2003

Goal : Improve the performance of Epidemic

Concept : Use past encounters to predict future best

Advantage:

Reasonable buffer utilization among nodes

Disadvantage:

No guarantee to meet a better node in a message life time

High communication overhead

Multiple copies without control

Spray and Wait:

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Author : T. Spyropoulos -2005

Goal : To reduce the overhead of Epidemic

Concept : Controlled flooding / Limit number of copies

Advantage:

Flooding is controlled

Disadvantage:

May experience long delivery delays

Random Movement (If the nodes that receive a copy of the bundle never cross paths with the destination, the system fails completely)/Random decision making

MaxProp:

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Author : John Burgess -2006

Goal : To increase the delivery rate & lower latency

Concept : Packet Dropping Policy

Advantage:

May experience long delays.

Disadvantage:

High processing cost in large scale network.

Aim & objective of Dissertation

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Aim of Dissertation

Paper objective Proposed new routing protocol for Delay Tolerant Network

using WSN nodes dedicated to localization / traceability , where GPS is not usable as in hospitals or in mine galleries

Research Methodology Evaluation of proposed routing mechanism through

simulations using network simulator NS-2 ,representing mining activity for which a set of mobile nodes plays the role of miners

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Problem Formulation

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Hybrid TechniqueTo achieve a High delivery ratio with low resource consumption,

Hybrid techniques will be required.

I Routing based on Knowledge:

• Epidemic routing.

II Routing based on additional nodes:

• Data mules

• Throwboxes

Filtered-Flooding Routing Protocol

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Flooding Strategy Delay-tolerant networks may rely on components that are

unreliable or unpredictable. To compensate for this, many routing strategies make multiple copies of each message and delivered to a set of nodes called Relay nodes

Which store the message until they can “contact” with the destination node.

Advantages: To increase the chance that at least one copy will be delivered to

the destination. No global or local knowledge about network To reduce delivery latency.

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Epidemic Routing :Each node adopt the ”store-carry-forward” paradigm by storing and forwarding packets to nodes that it encounters

Give a message copy To every node encountered essentially: flooding in a disconnected network

Epidemic Routing

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SV : Summary vector Summary vector of a mobile host is a brief summary of

messages that are currently present in the buffer of a mobile host.

When two mobile hosts come into contact with each other, they decide which messages are to be exchanged between them by looking at other host’s summary vector.

so that the absent messages in the vector are synchronized.

Message exchange mechanism

Message Vectors - I Node A encounters node B

Dest ID Seq. No.

D 0

G 1

F 0

Dest ID Seq. No.

D 0

E 0

F 0

F 1

Message Vector of A Message Vector of B

(G,1)

(E,0),(F,1)

Message Vectors - II After message exchange

Dest ID Seq. Num.

D 0

E 0

F 0

F 1

G 1

Dest ID Seq. Num.

D 0

E 0

F 0

F 1

G 1

Message Vector of A Message Vector of B

Current Problems Principal problem with Data collection in sparse sensor nw.

High energy consumption in multi-hop routing between widely separated nodes

Nodes may be static => how to bridge partitions? Nodes may be mobile, but slow => long delays

1. waiting for a contact to occur may take time

Solution: Use specialized nodes (DataMules or Message Ferries) to carry traffic between production nodes

Ferries are always mobile No energy considerations

Routing Based on Additional Nodes - I What is a Data MULE?

A data MULE is a mobile entity with an attached transceiver known as a Mobile Ubiquitous LAN Extension

A MULE can 1. Move to collect data from the sensors within radio

range 2. Buffer it ,& Drop off the data to wired access point

In the MULE architecture sensors save energy by short range transmission no routing protocol overhead low duty cycle of radio listening

Routing based on Additional nodes II

What is a Throughbox ?

Throw boxes : Routing proposed is based on the addition of fixed nodes called throw boxes acting as relays to create more contacts in the network.

Advantage High storage capacity, High computing power High energy.

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DTN Real-word Application Areas

Remote Area Networks

Military Battlefield Networks

Mobile Sensor Networks

Interplanetary Network

Hospital

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Application of DTN using WSN Mining gallery

A simple generic scenario where workers move in an underground mine consisting of two galleries, as shown in Figure.

Figure1. Mine Gallery

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Work done

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Simulation Parameter

Parameter Value

Nodes 50

Mobility Random way point

Approx. Range 250m

Simulation time 225 sec

Area 1000 * 1000

Packet size 512 bytes

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Simulation Scenario

Fig 1. Fig 2.

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Simulation Scenario

Fig 3. Fig 4.

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Results

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Plot of No of nodes vs. PDR • PDR is good for small size network – 80.7393 using TNAF

• but decreases as we increase the number of nodes in the network .

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Plot of No of nodes vs. Delay • Delay is large for small size network – 40.1421 using TNAF

• but decreases as we increase the number of nodes in the network .

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Conclusion• The PDR is good for small size network but decreases as we

increase the number of nodes in the network.

• Delay is large for small size network but decreases as we increase the number of nodes in the network .

• Delay-tolerant Networking (DTN) enables communication in sparse mobile ad-hoc networks and other challenged environments where traditional networking fail.

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Further work• Throughput evaluation of proposed routing protocol .

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References[1] H. Karl and A. Willig, Protocols and Architectures for Wireless Sensor Networks.Wiley-Interscience, October 2007.[2] A. keranen, T. Karkkainen, and T. Ott, “Simulating Mobility and DTNs with the ONE,” in Journal of Communications (JCM), A.publisher, Ed., vol. 5, no. 2, 2010, pp. 92–105.[3] H. Frey, S. R¨uhrup, and I. Stojmenovi´c, “Routing in Wireless Sensor Networks,” in Guide to Wireless Sensor Networks, ser. Computer Communications and Networks, S. C. Misra, I. Woungang, and S. Misra, Eds. Springer London, 2009, pp. 81–111.[4] A. Vahdat and D. Becker, “Epidemic routing for partially-connected ad hoc networks,” Duke University, Tech. Rep. CS-2000-06, July 2000.[5] T. Spyropoulos, K. Psounis, and C. S. Raghavendra, “Spray and wait: an efficient routing scheme for intermittently connected mobile networks,” in WDTN ’05: Proceeding of the 2005 ACM SIGCOMM workshop on Delay-tolerant networking. ACM Press, 2005, pp. 252–259.[6] J. Burgess, B. Gallagher, D. Jensen, and B. N. Levine, “Maxprop: Routing for vehicle-based disruption-tolerant networks,” in Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications. IEEE, April 2006, pp. 1–11.

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References[7] R. Sugihara and R. K. Gupta, “Speed control and scheduling of Data MULEs in Sensor Networks,” ACM Trans. Sen. Netw., vol. 7, no. 1, pp.1–29, 2010.[8] K. A. Harras and K. C. Almeroth, “Transport layer issues in delay tolerant mobile networks,” in IFIP NETWORKING, vol. 3976. Springer,2006, pp. 463–475. [9] I. Rhee, M. Shin, S. Hong, K. Lee, and S. Chong, “On the Levy-Walk nature of human mobility,” in IEEE INFOCOM 2008 - IEEE Conferenceon Computer Communications. IEEE, April 2008, pp. 924–932.[10] W. Zhao, Y. Chen, M. Ammar, M. Corner, B. Levine, and E. Zegura, “Capacity enhancement using throwboxes in DTNs,” in In Proc. IEEEIntl Conf on Mobile Ad hoc and Sensor Systems (MASS), 2006, pp. 31–40.[11] http://www.isi.edu/nsnam/ns/.

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Q & A