The document proposes a new routing protocol called Path Addressed Depth Based Routing (PADBR) to improve energy efficiency in underwater acoustic sensor networks. It aims to reduce flooding, collisions, and energy consumption compared to existing depth-based routing protocols. PADBR selects the next hop node based on depth difference and maintains a list of neighbor nodes to directly forward packets to instead of broadcasting. Simulation results show PADBR achieves higher packet delivery rates and network lifetime with reduced end-to-end delay and energy consumption compared to traditional depth-based routing.

1. Path Addressed Depth Based Routing
An Energy Efficient Protocol For Routing in Underwater Acoustic Sensor
Networks
Aiswarya Issac
April 25, 2017
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2. Outline
1 Introduction
2 Problem Definition
3 Literature Survey
4 Proposed Protocol Implementation
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3. Introduction and Scope
Underwater Wireless Sensor Networks(UWSN) can be used for many
applications like Submarine Surveillance, Pipeline monitoring,
Pollution control, etc.
UWSN uses Acoustic waves for communication which causes high
propagation delay in communication.
Energy Conservation is of prime importance in UWSN.
Networking protocols play an important role in energy conservation.
Routing protocols helps in finding out the shortest path from source
to sink in a multi-hop environment.
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4. Problem Definition
Design an energy efficient routing protocol for Dynamic Underwater
Acoustic Networks.
The protocol should help to minimise energy utilisation.
The protocol should handle the dynamic topology of nodes in the
network.
The protocol should control flooding of packets and hence reduce the
number of collisions.
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5. Literature Survey
The routing protocols proposed in literature can be classified into 3 main
sections:
Location Based Protocols: Require Location Information for all nodes
in the network.
VBF[1](2005), FBR[3](2008) HHVBF[2](2010)
Depth Based Protocols: Requires Depth Information for all the nodes
in the network.
DBR[4](2008), EEDBR[5](2011), ddbr[6](2015)
Hop-Count Based Protocols: Requires Hop-count Information for all
nodes in the network.
H2DAB[7](2009), CRP[8](2012), CARP[9](2015)
Depth Based Protocols are found to be more efficient.
Only Depth information is needed.
No overhead to compute the hopcount.
High Collision Rate and High energy consumption.
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6. Depth Based Routing
Figure: Network Architecture and Protocol Illustration
Figure: Packet Format
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7. Depth Based Routing
Data transfer always takes place from deep to shallower nodes, and
finally to sink.
A node receiving a packet will check whether it is eligible for
re-forwarding the packet.
If a node identifies itself as a prospective forwarder, it will calculate
the holding time.
Re-forwarding happens only after the completion of holding time.
Data Structures
2 Queues - Q1 and Q2.
The Queue Q1 stores the packet along with their holding time.
An item from Q1 is removed either when holding time expires or the
node overhears the same packet being broadcasted by another node.
The Queue Q2 is the packet history buffer
Q2 prevents a node from sending already sent packet.
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8. Proposed Protocol
If a node receives packet from a shallower node, the address of the
packet sender is saved in a list as neighbour node.
When a node wants to transmit some data, it will look for neighbour
nodes in the list.
If there are multiple entries in the list, a node is randomly selected
from the list.
If a node receives packet from a deeper node, it will re-forward the
packet if depth difference between the nodes is greater than a
threshold.
Protocol proposed is as simple as flooding; but with reduced collisions
and improved energy utilisation.
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9. Proposed Protocol Implementation
Reducing Flooding Rate
Maintain additional Data Structure - List NextNode
When a node A receives packet from a lower-depth node B, instead of
discarding the packet, save the node ID in NextNode list if the depth
difference is greater than threshold T0.
Next time when A wants to send data, it can directly send to B instead
of broadcasting. This reduces the flooding rate.
A node from NextNode list will be selected as the rely node randomly.
Reducing Delay
Data packets are always broadcasted in DBR. Therefore holding time is
required to reduce collision.
In proposed Improved DBR, holding time is not required when packets
are not broadcasted.
Packets can be forwarded as soon as MAC issues an AGREE message.
This helps to reduce the average end to end delay.
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10. Proposed Protocol Implementation
Reduced Energy Consumption
As the number of re-transmissions are reduced, the energy
consumption is drastically reduced.
Load Balancing
In DBR, the shallower nodes experience much higher loads, and they
tend to die out sooner.
To improve load balancing, more nodes are placed at shallower depths.
Moreover, the node’s holding time is improved such that nodes with
high residual energy will transmit first.
Handling Mobility
In order to handle mobility, the NextNode needs to be reinitialized at
particular intervals.
This reinitialization time r should not be too small or too big.
If r is too small - PADBR becomes similar to DBR.
If r is too big - Reduction in Packet Delivery Rate.
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11. Proposed Protocol Implementation
Simulation Settings
The proposed protocol was implemented using Unet.
Nodes are randomly deployed in an region of 4x4x4km3.
Maximum range of each node set to 2 km[13].
Two sink nodes deployed on the surface.
Each transmission consumes 2 J of energy.
Each reception consumes 0.1 J of energy.
Initial energy - 300 J.
Simulation time was set to 12 hours and executed in Discrete Event
Simulation mode.
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12. Proposed Protocol Implementation
Results Obtained
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13. Summary
Routing protocol for underwater network was designed and
implemented using Unet.
Advantages of proposed protocol:
High Packet Delivery Rate
Load Balancing and High Network Lifetime
Reduced End-to-End Delay
Reduction in energy consumption.
The code can be directly ported to compatible modem for real life
testing.
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14. References I
[1]Xie, Peng, Jun-Hong Cui, and Li Lao. VBF: Vector-Based
Forwarding Protocol for Underwater Sensor Networks. UCONN CSE
Technical Report: UbiNet-TR05-03 (BECAT/CSETR-05-6), February
2005.
[2]Xie P, Zhou Z, Nicolaou N, See A, Cui JH, Shi Z. Efficient
vector-based forwarding for underwater sensor networks. EURASIP
Journal on Wireless Communications and Networking. June
2010;2010(1):195910.
[3]Jornet, Josep Miquel, Milica Stojanovic, and Michele Zorzi.
Focused beam routing protocol for underwater acoustic networks.
Proceedings of the third ACM international workshop on Underwater
Networks. ACM, 2008.
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15. References II
[4] Yan, Hai, Zhijie Jerry Shi, and Jun-Hong Cui, DBR: depth-based
routing for underwater sensor networks, International Conference on
Research in Networking. Springer Berlin Heidelberg, 2008.
[5]Wahid A, Lee S, Jeong HJ, Kim D Eedbr: Energy-efficient
depth-based routing protocol for underwater wireless sensor networks.
Advanced Computer Science and Information Technology. Springer
Berlin Heidelberg, 223-234, 2011.
[6]Diao, Boyu, et al. Improving both energy and time efficiency of
depth-based routing for underwater sensor networks. International
Journal of Distributed Sensor Networks, Jan 2015.
[7]Ayaz, Muhammad, and Azween Abdullah. Hop-by-hop dynamic
addressing based (H2-DAB) routing protocol for underwater wireless
sensor networks. Information and Multimedia Technology, 2009.
ICIMT’09. International Conference on. IEEE, 2009.
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16. References III
[8]Wahid, Abdul, and Dongkyun Kim. Connectivity-based routing
protocol for underwater wireless sensor networks. 2012 International
Conference on ICT Convergence (ICTC). IEEE, October 2012.
[9]Basagni S, Petrioli C, Petroccia R, Spaccini D. CARP: A
channel-aware routing protocol for underwater acoustic wireless
networks. Ad Hoc Networks. Nov 2015 30;34:92-104.
[10]Aiswarya Issac, Sumi A Samad, Jereesh A.S. ”Software Tools for
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IEEE Proceedings, April 2017.
[11]Masiero, Riccardo, Saiful Azad et. DESERT Underwater: an
NS-Miracle-based framework to DEsign, Simulate, Emulate and
Realize Test-beds for Underwater network protocols. In 2012
Oceans-Yeosu, pp. 1-10. IEEE, 2012.
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17. References IV
[12]C.Petrioli and R.Petroccia, SUNSET: Simulation, Emulation and
Real-life Testing of Underwater Wireless Sensor Networks, in
Proceedings of IEEE UComms 2012, IEEE Computer Society,
September, 12-14 2012.
[13] M. Chitre, R. Bhatnagar, and W.-S. Soh, UnetStack: an
Agent-based Software Stack and Simulator for Underwater Networks,
in: Proceedings of IEEE OCEANS14, September 2014.
[14]Chitre, Mandar, Mehul Motani, and Shiraz Shahabudeen.
Throughput of networks with large propagation delays. IEEE Journal
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[15]Li C, Xu Y, Diao B, Wang Q, An Z. DBR-MAC: A Depth-Based
Routing Aware MAC Protocol for Data Collection in Underwater
Acoustic Sensor Networks. IEEE Sensors Journal 16.10 (2016):
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18. THANK YOU!