EESAA: Energy Efficient Sleep Awake Aware Intelligent Sensor

Network Routing ProtocolTalha Naeem Qureshi

Joint work withTauseef Shah and Nadeem Javaid

COMSATS, Institute of Information Technology,44000, Islamabad, Pakistan

www.comsats.edu.pkwww.njavaid.com

15th International Multi Topic Conference (INMIC), Islamabad, Pakistan 13th to 15th December 2012

Wireless Sensor Networks (WSNs) are composed of multiple unattended ultra-small, limited-power sensor nodes

Sensor nodes are deployed randomly in the area of interest

Sensor nodes have limited processing, wireless communication and power resource capabilities

Sensor nodes send sensed data to sink or Base Station (BS)

Wireless Sensor Networks

Goal:o Prolong network lifetime/coverage

Clustering is useful in reducing energy consumption

Routing in WSNs

LEACH – Low Energy Adaptive Clustering Hierarchy [Heinzelman et al., 2000] SEP - Stable Election Protocol [G. Smaragdakis et al., 2004] DEEC - Distributed Energy Efficient Clustering [Li Qing et al., 2006] LEACH:

◦ Unable to differentiate nodes in terms of energy (homogeneous)◦ Node i chooses random number s between 0 and 1◦ If s < T(si), node i becomes a Cluster Head (CH) for the current round where:

where:◦ T(si)=threshold◦ Pi = desired percentage of CHs◦ G = set of nodes that have not been a CH in the last 1/P rounds

Clustering based protocols

Each node is elected CH once every 1/P rounds (epoch length)

On average, n x P nodes elected per round◦ n = total number of nodes

LEACH

Differentiate nodes in terms of their energy (heterogeneous)

Consider two types of nodes w.r.t energy: normal and advanced nodes

where:◦ Energy of advanced nodes > Energy of normal nodes

CH selection probability of advanced nodes is greater than normal nodes

Use same threshold T(si) for CH selection as described by LEACH

Each node is elected CH once every 1/P rounds (epoch length)

Epoch of advanced nodes < epoch of normal nodes

SEP

Differentiate nodes in terms of their energy (heterogeneous)

Consider multiple energy levels of nodes Use same threshold T(si) for CH selection as

described by LEACH Epoch of high energy nodes < epoch of low

energy nodes

DEEC

Mostly sensor nodes overlaps each other or placed close to each other during deployment

Overlapped and close nodes have same sensed data There is no need to send same sensed data two times to BS

Nodes Deployment Issues

Sending same data two times to BS cause ◦ Energy loss◦ Stability period and life time of WSN decreases◦ Extra overhead on sink

No previous protocol including LEACH, SEP and DEEC is addressing this issue

Nodes Deployment Issues

Our goal:◦ To minimize energy consumption ◦ To enhance network stability period and network lifetime.

Concept of pairing is introduced Sensor nodes of same application and at minimum

distance between them will form a pair for data sensing and communication

CHs selection technique is enhanced CH selection on basis of remaining energy of nodes CH of current round will predict the CH for next

round

Our EESAA: Energy Efficient Sleep Awake Aware Intelligent Sensor Network Routing Protocol

Mechanism:◦ Sensor nodes are supposed to be equipped with

Global Positioning System (GPS)◦ Senor nodes measure their location through GPS◦ Nodes transmit their location information to sink◦ In first round clusters are formed by same

mechanism described by LEACH◦ Nodes which are at minimum distance from each

other in their intra cluster transmission range and of same application type are coupled in pair by BS

EESAA

Mechanism:◦ Sink broadcast pairing information to all the nodes in network◦ Nodes become aware of their coupled node

According to the proposed scheme, The nodes switch between ”Sleep” and ”Awake” mode during a single communication Interval

Initially node in a pair, switch into Awake mode also called Active-mode if its distance from the sink is less then its coupled node

Node in Active-mode will gather data from surroundings and transmit data to CHs

During this period transceiver of the coupled node will remain off and switches into Sleep-mode

EESAA

In next round, nodes in Active-mode switch into Sleep-mode and Sleep-mode nodes switch into active-mode

Energy consumption is minimized because nodes in Sleep-modes save their energy by not communicating with the CHs

Unpaired nodes remain in Active-mode for every round till their energy resources depleted

EESAA

Green circles – coupled or paired nodes Read circles – unpaired or isolated nodes

EESAA

CH selection mechanism:◦ Initially, in first round CHs are selected by same

mechanism described by LEACH◦ CHs selection after first round is based on

remaining energy of each node◦ Nodes in Active-mode take participation in CH

election process◦ During start of round, nodes also transmit their

energy information to CH◦ CH computes the remaining energy of every node

in cluster and its distance from each node and select CH for the next upcoming round

EESAA

Transmission phase:◦ When node has been selected as CH, it broadcasts an

advertisement message to whole network. ◦ Only Active-mode nodes hear the broadcast

advertisements from different CHs◦ They select their CHs on the basis of Received Signal

Strength Indication (RSSI) of advertisements Nodes in Active-mode, transmit their sensed

data to CH during their assigned TDMA slots Nodes in Sleep-mode do not take participation in

data transmission and save their energy by turning their transceiver off

EESAA

Node mode setup algorithm

EESAA

Performance metrics:◦ Stability period: It is duration of network operation

from start till first node dies◦ Network lifetime: Network lifetime is duration from

start till last node is alive◦ Instability period: It is duration of network

operation from first node dies till the least node dies

◦ Number of CHs: It indicates the number of clusters generated per round

◦ Packet to BS: It is rate of successful data delivery to BS from CHs

Simulation Results

Simulation Results In EESAA first node dies around 1800 round Stability period of EESAA is almost 120% 50% and 35%

greater than LEACH, SEP and DEEC respectively EESAA has 100% 102% and 50% network lifetime as

compared to LEACH, SEP and DEEC

Simulation Results SEP, DEEC and LEACH has more uncertainties in CHs

selection Random number of CHs are selected in every round but

ESSA has controlled CHs selection. EESAA efficient CHs selection algorithm helps it in better

and constant data rate transmission to BS

Simulation Results EESAA has sleep-awake policy for nodes Less number of data is transmitted to BS in starting rounds

due to sleep mode of some nodes But after 4300 rounds, EESAA has highest data rate

Conclusion EESAA is location aware protocol EESAA minimizes energy consumption by

sleep-awake mechanism Simulation results show significant

improvement all performance metrics as compared to existing routing protocols e.g., SEP, LEACH and DEEC

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