SPARCO: Stochastic Performance Analysis with Reliability and Cooperation for Underwater Wireless Sensor Networks

Hindawi Publishing Corporation Journal of Sensors Volume 2016, Article ID 7604163, 17 pages http://dx.doi.org/10.1155/2016/7604163 Research Article SPARCO: Stochastic Performance Analysis with Reliability and Cooperation for Underwater Wireless Sensor Networks Sheeraz Ahmed,1,2 Nadeem Javaid,1 Ashfaq Ahmad,1 Imran Ahmed,2 Mehr Yahya Durrani,3 Armughan Ali,3 Syed Bilal Haider,3 and Manzoor Ilahi1 1 COMSATS Institute of Information Technology, Islamabad, Pakistan Institute of Management Sciences (IMS), Peshawar, Pakistan 3 COMSATS Institute of Information Technology, Attock, Pakistan 2 Correspondence should be addressed to Nadeem Javaid; Received 22 November 2015; Accepted 5 January 2016 Academic Editor: Wei Cao Copyright © 2016 Sheeraz Ahmed et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Reliability is a key factor for application-oriented Underwater Sensor Networks (UWSNs) which are utilized for gaining certain objectives and a demand always exists for efficient data routing mechanisms. Cooperative routing is a promising technique which utilizes the broadcast feature of wireless medium and forwards data with cooperation using sensor nodes as relays. Here, we present a cooperation-based routing protocol for underwater networks to enhance their performance called Stochastic Performance Analysis with Reliability and Cooperation (SPARCO). Cooperative communication is explored in order to design an energy-efficient routing scheme for UWSNs. Each node of the network is assumed to be consisting of a single omnidirectional antenna and multiple nodes cooperatively forward their transmissions taking advantage of spatial diversity to reduce energy consumption. Both multihop and single-hop schemes are exploited which contribute to lowering of path-losses present in the channels connecting nodes and forwarding of data. Simulations demonstrate that SPARCO protocol functions better regarding end-to-end delay, network lifetime, and energy consumption comparative to noncooperative routing protocol—improved Adaptive Mobility of Courier nodes in Threshold-optimized Depth-based routing (iAMCTD). The performance is also compared with three cooperation-based routing protocols for UWSN: Cognitive Cooperation (Cog-Coop), Cooperative Depth-Based Routing (CoDBR), and Cooperative Partner Node Selection Criteria for Cooperative Routing (Coop Re and dth). 1. Introduction UWSNs consist of sensors and vehicles that are deployed over a given region to perform collaborative monitoring tasks. These networks offer variety of applications like tactical surveillance, environmental monitoring, assisted navigation, resource investigation, and disaster prevention. The physical layer has a strong influence on UWSNs due to the presence of acoustic waves. Acoustic waves are the most accurate source of reaching up to desirable range and rate of data transmission in UW communications. Radio waves do not support required data rate and range as they get absorbed in water very quickly. New achievements in underwater acoustic (UWA) communications, however, make adequate data forwarding over long distances. Many techniques have been investigated on developing networking solutions for UWSNs including acoustic channel modeling, physical layer transmission analysis, and networking protocols. Acoustic waves experience large delay spreads as they move at the speed of 1500 m/s. This speed makes one-fifth speed as that of radio waves. Path-loss, in the case of radio channels, depends solely on the length of the link; but the acoustic waves in UW experience both link length and frequency dependent path-losses. Bubbles and suspended particles in water make wide dispersion in acoustic waves. Also, the reflections from surface of water as well as from the bed of the sea increase the channel fading. All these factors 2 have to be taken into account for the design of UWA wireless systems. Having now sufficient technological advancements made in the field of radio communications, researches are trying to enhance the working of UW systems using modern techniques adopted from radio communications. A promising technique is cooperative communication, already being used in terrestrial WSNs. It is a potential approach for distributed UWSNs to upgrade the quality of link connecting sensors as well as the reliability in both point-to-point and multipoint environments, having multiple relays doing cooperation. Wireless network designs take into account the diversity to improve the overall successful transmissions by allowing duplicate signals at the receiver. In contrast to this approach, Multiple-Input Multiple-Output (MIMO) technique also uses a promising mechanism to improve Signal-to-Noise Ratio (SNR) by enhancing diversity gain. But, the technique needs extra equipment cost for each sensor with much complexity. A different approach for gaining diversity is to utilize several sensors cooperating with each other to upgrade the quality of communication channel. In variation to an individual sensor having an antenna array, duplicate data is forwarded by an array of distributed antennas comprised of several sensors to reach the end-point but introducing some delay. Spatial diversity concept has directed regular efforts to its use in wireless networks particularly in WSNs. If various paths existing between two end devices are not dependent on each other and have adequate working, channel efficiency can be improved by forwarding multiple duplicates of data along these links and merging them at the destination. The total error probability decreases since the paths are independent, which makes the channel and system performance increase. However, in general case of WSNs, nodes are very small to that needed for the support of such distributed antennas. Hence, to combat such issues, the idea of cooperative routing is proposed. Cooperation is defined as a group of entities working together to achieve a common goal while sharing each other’s resources. In these systems, transmitter forwards one copy of data packets to a node acting as relay. The relay then decodes or amplifies each data packet as the scheme suggests and reforwards it to the final receiver. Relay node uses a path which is generally different from the direct path. The destination merges or utilizes both of the received signals to extract the forwarded information. Cooperative diversity, an alternative to combat fading in wireless channels, allows distributed users to help relay information of each other to explore inherent spatial diversity present in channels. Various cooperation-based protocols have been proposed in literature like fixed relaying protocol, adaptive relaying protocol, user cooperation protocol, and coded cooperation schemes. In fixed relaying schemes, such as Amplify-and-Forward (AF) a (...truncated)