Randomized fault-tolerant virtual backbone tree to improve the

lifetime of Wireless Sensor Networks

Sajjad RostamiAzad University of Qazvin

Thursday, May 28, 2015

Reviews processed and recommended for publication to the Editor-in-Chief by Associate Editor Dr. Srinivasan Rajavelu.

Autors: K. Suganthi(a), B. Vinayagasundaram(b) , J. Aarthi(a)a:Department of Computer Technology, Anna University, Chennai 600044, Indiab:Department of Information Technology, Anna University, Chennai 600044, India

iSchool

Today’s Topics Introduction to wireless sensor networks (WSN) Network lifetime

Virtual backbones

Issues and challenges

Proposed FTVBT model Randomized FTVBT

Conclusion

iSchool

What’s the WSN? deployed in a region that needs to be monitored Large numbers of sensors

low power low cost memory/computationally-constrained

Scope of energy consumption by WSNs Communication Sensing computation

iSchool

Network lifetime & Virtual backbone network lifetime has been defined in various

ways: mean expiration time specific fraction of nodes remains first loss of reporting

Virtual backbone algorithms: Energy-aware Virtual Backbone Tree (EVBT) Multihop cluster-based stable backbone tree Virtual backbone Tree Algorithm for Minimal energy

consumption (ViTAMin).

iSchool

Energy-efficient routing algorithms cluster

Use a hop limit-based model where the sink is within the hop limit of a cluster member that transfers the data directly to the sink node

virtual backbone-based routing provide an infrastructure for efficient communication

with the sink node All of the communication between a particular sensor

node and the sink node occurs via the tree nodes

iSchool

Backbone Construction algorithms EVBT

the sink node transmits a broadcast request (BCR) packet to all of the nodes in its sensing range

m-EVBT ViTAMin finds the shortest path to the sink for each tree

node by adding a distance parameter to track the existing BCR packet

iSchool

Strategies used to select the tree nodes

iSchool

Strategies used to select the tree nodes Modified EVBT (m-EVBT)

Reduces the total energy consumption by utilizing the distance between nodes and energy

Like EVBT, the energy consumption information is

passed via an EVBT construction request (ECR) packet

Only nodes with energy greater than the threshold are considered for selection as tree nodes

Distributed Breadth First Search are run

iSchool

Issues and challenges

iSchool

FTVBT model

iSchool

FTVBT model(Backbone construction)

iSchool

FTVBT model(Finding a suitable parent for child tree nodes)

iSchool

FTVBT model(Finding a parent of associated non-tree nodes)

iSchool

FTVBT model(Backbone reconstruction)

iSchool

FTVBT model(Backbone Reconstruction (continued))

iSchool

Randomized FTVBT

FTVBT selects tree nodes deterministically based

on a fitness factor.

Instead of always selecting the tree with the

highest fitness factor, it is possible to select all of

the tree nodes as parents based on their fitness

factor.

iSchool

FTVBT maintains the N-N lifetime Let path(n) be the path from the sink to a node n

For all nodes ‘n’ the path is identified through the tree nodes

When the nodes are far apart, it might not be possible to cover it using a single virtual backbone

when the number of dependents is greater than the average number of reachable local tree nodes, the number of dependents is reduced

Ideally, this value should be twice the average number of dependents in nearby tree nodes

iSchool

FTVBT maintains the N-N lifetime some of the non-tree nodes are converted into

tree nodes when it is necessary to cover all the nodes

According to the N-of-N lifetime concept, if there are few nodes left in the deployed area, backbones must be formed that comprise part of the network

Until the number of alive nodes becomes zero, the sink collects data and maintains the NN lifetime

iSchool

Simulation

iSchool

Simulation

iSchool

Conclusion FTVBT method identifies hotspots and distributes

the dependents across tree nodes, thereby: Increasing the durability of the virtual backbone Increasing the overall network lifetime of WSNs

iSchool

Thanks for Attention