Presented by: Sheeraz Ahmed 1

 ARCUN a reliable, energy-efficient and high throughput routing protocol  Cooperative routing a potential scheme for lowering channel fading and increasing transmission efficiency  Exploits broadcast nature of wireless medium and transmits cooperatively using as relays  Focuses on Amplify-and-Forward (AF) protocol at relay node and Fixed Ratio Combining (FRC) at the receiver  Utilizes merits of multi-hoping and cooperative routing for higher stability period and end-to-end delay with greater network lifetime

 Underwater Wireless Sensor Network (UWSN) ▪ allows remote monitoring of underwater environment ▪ comprises of various underwater dispersed sensor nodes ▪ has limited energy resources  Design challenges ▪ well designed network topology ▪ efficient use of both single-hop and multi-hop transmissions ▪ reliable data delivery ▪ optimal energy consumption ▪ signal subjected to noise, fading, attenuation, absorption by water 3

 Cooperation in UWSNs ▪ Achieves higher energy savings ▪ Enhances end-to-end network throughput ▪ Reliable delivery of information ▪ Overcomes the effect of ocean noise and attenuation ▪ Higher throughput with minimum energy consumption ▪ Sensors acting as relay as well as transmitters 4

 ARCUN proposes mechanism with improved SNR and minimum path-loss over a link  Mitigating the effects of multi-path fading and noise by co-operative communication  Utilizing merits of both single-hop and multi- hop communication  Reducing redundant transmissions  Considering path-loss in the link along-with co- operation  Diversity a promising technique to overcome limitations of WSN 5

 Large number of routing schemes proposed for UWSN; categorized as location-based and location- free communication protocols.  An efficient technique in localization-free category DBR [1], based on data forwarding through low- depth sensor nodes.  EEDBR [2] a constructive framework for maximizing the network lifetime by utilizing both depth and residual energy of sensor nodes. Minimizes end-to-end delay along with better energy consumption of the low-depth nodes. [1] Yan, Hai, Zhijie Jerry Shi, and Jun-Hong Cui. “DBR: depth-based routing for underwater sensor networks.” Networking 2008 Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet. Springer Berlin Heidelberg, (2008) [2] Wahid, Abdul, and Dongkyun Kim. “An energy efficient localization-free routing protocol for underwater wireless sensor networks.” International journal of distributed sensor networks (2012).

 Authors in [17] proposed the idea of range extension using less burdened nodes as next hop. In REACT, unused energy of the network is utilized that leads to network lifetime extension.  In [18], the author has explored the benefits of cooperative diversity for linear arrangement of WSN, using AF protocol at relay and a lightweight combining strategy at receiver. [17] J. W. Jung and M. A. Ingram, Residual-energy-activated cooperative transmission (REACT) to avoid the energy hole, in Proceedings of the IEEE International Conference on Communications Workshops (ICC '10), pp. 1–5, May [18] Khalid El-Darymli, Amplify-and-Forward Cooperative Relaying for a Linear Wireless Sensor Network, in proceedings of the IEEE International conference on Systems Man and Cybernetics(SMC),2010.

 In [18], authors proposed a contention free multi- channel MAC protocol for UWSNs that works well even when nodes experience uneven and bursty traffic loads  In [19], authors proposed a Forwarding-function based routing protocol improved Adaptive Mobility of Courier nodes in Threshold-optimized Depth-based routing (iAMCTD) for UWSNs. Maximizes the life-time of reactive UWSNs by optimized mobility pattern of sink. [18] Chao, ChihMin, and MingWei Lu. “Energy efficient transmissions for bursty traffic in underwater sensor networks.” International Journal of Ad Hoc and Ubiquitous Computing 13, no. 1 (2013): 1-9. [19] Javaid, N., M. R. Jafri, Z. A. Khan, U. Qasim, T. A. Alghamdi, and M. Ali. “iAMCTD: improved Adaptive Mobility of Courier Nodes in Threshold-Optimized DBR Protocol for Underwater Wireless Sensor Networks.” Hindawi IJDSN, (2014).

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10 Fig : A linear 3 node arrangement using relay node for co-operation In phase 1, S transmits its information to both R and D simultaneously In phase 2, R transmits received information to D

 Network is assumed to be divided into layers going deep into underwater.  Composed of heterogeneous nodes,  Each node has a single omni-directional antenna.  In case of normal data, the source data always follows the relay path in a cooperation mode

 INITIALIZATION PHASE:  Three tasks are performed in this phase;  each node is informed about its neighbors,  location of sinks on the surface of water is identified and  all the possible routes to various sinks are also evaluated.  Each node calculates its weights using the formula.

 Mathematical Modeling Signal attenuated by effects of free space path loss and fading, and both included in hs; Ns are noise components introduced. In phase 2, R retransmits the signal to the D received in phase 1, after applying some processing.

 Relay Selection and Routing Phase If multiple relay nodes are available in the path and a source node has a sink node as its next-hop node, then a relay node will never trigger co-operation. It will help to maximize the minimum residual energy left after data transmission.

 Relay Strategy  Considering AF technique at relay R i which multiplies the received signal from Si by amplification factor β before forwarding it to D i.e. yRD = β (ySR).  If Ps and Pr are the transmission powers at S and R, respectively, then

 Relay Strategy  As power is defined as energy per unit time, hence expressing the transmission powers of S and R in terms of energy

 Combining Strategy  Each destination D implements a diversity combining technique to combine received signals from S and R.  FRC is used as the combining strategy.  Instead of just adding up the incoming signals, they are weighted with a constant ratio.

 Combining Strategy  An optimal value of the weights ratio is 2 : 1 in case of amplify−and−forward technique

 Combining Strategy  If the transmitted symbol xs has an average energy of unity, then the SNR of the FRC output is

 Noise Model in UW Channel

22 Stability Period: Stability period is longer in ARCUN is due to: Non-continuous data transmission Relay selection mechanism Consideration of channel losses in the medium Exclusion of abrupt energy consumption of nodes due to availability of cooperation-based relay nodes

Packet Delivery Ratio: 23 Higher Packet Delivery ratio of ARCUN is due to : Link redundancy due to cooperation Cooperative relaying decrease the chance of packet drops

Path-loss: 24 Path-loss in ARCUN is reduced due to : Scheme based on channel estimation and considering UW losses Packet forwarded with the higher reliability, leading to lower retransmissions. Use of cooperation makes the data forwarding much better with the help of relay nodes and load balancing is also achieved

 ARCUN, a new cooperative routing protocol for UWSNs.  Purpose is to exploit cooperative routing in heterogeneous network to enhance UWSN performance.  Mathematical modeling using co-operative routing helped reduce energy consumption in existing path-loss and cumulative noise effects.

 Achieves greater stability period, whereas, use of cooperative routing increases the throughput of the network.  ARCUN performs better than AMCTD and EEDBR and is superior in terms of packet delivery ratio, path-loss and stability period.