1. EESAA: Energy Efficient Sleep Awake Aware Intelligent Sensor Network Routing Protocol
Talha Naeem Qureshi
Joint work with
Tauseef Shah and Nadeem Javaid
COMSATS, Institute of Information Technology,
44000, Islamabad, Pakistan
15th International Multi Topic Conference (INMIC), Islamabad, Pakistan
13th to 15th December 2012

2. Wireless Sensor Networks
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)

3. Routing in WSNs
Goal:
Prolong network lifetime/coverage
Clustering is useful in reducing energy consumption

4. Clustering based protocols
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

5. LEACH 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

6. SEP 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

7. DEEC 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

8. Nodes Deployment Issues
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

9. 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

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

11. EESAA
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

12. 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

13. 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

14. EESAA Green circles – coupled or paired nodes
Read circles – unpaired or isolated nodes

15. 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

16. 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

17. EESAA
Node mode setup algorithm

18. Simulation Results 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

19. 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

20. 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

21. 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

22. For more information please check
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
For more information please check