OMUS Efficient Opportunistic Routing in Multi-Modal Underwater Sensor Networks
Abstract : Underwater wireless sensor networks (UWSNs) have emerged as an enabling technology for aquatic monitoring. However, data delivery in UWSNs is challenging, due to the harsh aquatic environment and characteristics of the underwater acoustic channel. In recent years, underwater nodes with multi-modal communication capabilities have been proposed to create communication diversity and improve data delivery in UWSNs. Nevertheless, less attention has been devoted to the design of networking protocols leveraging multi-modal communication capabilities of underwater nodes. In this paper, we propose a novel stochastic model for the study of opportunistic routing (OR) in multi-modal UWSNs. We also design two candidate set selection heuristics, named OMUS-E and OMUS-D, for the joint selection of the most suitable acoustic modem for data transmission and next-hop forwarder candidate nodes at each hop, aimed to reduce the energy consumption and improve the network data delivery ratio in multi-modal UWSNs, respectively. Numerical results showed that both proposed heuristics reduced the energy consumption by 65%, 70%, and 75% as compared to the DBR, HydroCast, and GEDAR classical related work protocols, while maintaining a similar data delivery ratio. Furthermore, the proposed solutions outperformed the CAPTAIN routing protocol in terms of data delivery ratio, while maintaining comparable energy consumption.
? Our new protocol is better than existing underwater routing protocols mainly by implementing the hop count discovery, which reduces the network overhead caused by periodic beacons and retransmissions and improves the packet delivery ratio while also increasing energy efficiency, since packets are only transmitted if a path is found from the source to the sink(s).
? The existing OR protocols in UWSNs can be classified into two main categories based on their positioning information: Geography-based routing protocols and Pressure-based routing protocols.
? In this work, two different scenarios were simulated using the network topologies that exist in.
? Routing algorithms for UWSNs have a great impact on several performance indices including the end-to-end delay, the energy consumption and the packet delivery ratio.
? The first problem that we address is the derivation of the optimal p(x) conditioned on the expected number of forwarders v.
? Having more than 1 expected forwarder may be useful to create redundant routes to the surface and to increase the packet delivery ratio.
? Aside from these works, many other papers address the problem of the performance evaluation and optimisation of UWSNs protocol by means of stochastic simulation.
• Many communication protocols have been proposed to address different Terrestrial Wireless Sensor Networks (TWSNs) issues , which make such networks widely investigated.
• These proposed protocols for UWSNs have considered various underwater parameters and addressed different problems.
• Opportunistic Routing (OR) has been proposed as a novel technique to improve network function by mitigating high bit errors and losses due to shadow zones, limited bandwidth, high power consumption, and signal spreading.
• Implementing the proposed hop count discovery technique inspired by DSR instead of flooding periodic beacons widely used in the literature ensures less network communication overhead and lower network resource consumption.
? This is the case for many protocols including the depth based routing (DBR) that is still one of the mostly used protocols in actual implementations of UWSNs and is is adoped as benchmark for the performance evaluation of new routing protocols.
? Apart from UWSNs, analytical models have also been devised in the area of vehicular networks to optimize the performance of opportunistic routing protocols.
? The analytical model allowed us to introduce an efficient method for the computation of the optimal depth threshold given a target packet delivery probability when the nodes’ spatial distribution can be modelled by a homogeneous PPP.
? The simulation tool that we have used is specialised for underwater networks, namely AquaSimNG, which is based on NS3 libraries
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