Towards Ultra-Reliable Low-Latency Underwater Optical Wireless Communications

Abstract

The superiority of optical communications in underwater mediums, in terms of higher data rate and reliability, makes underwater optical wireless communications (UOWC) more favorable to provide ultra-reliable low-latency underwater communications, as compared to other wireless technologies, e.g., acoustic and radio frequency (RF) communications. UOWC limited transmission range, however, remains a major hurdle against assessing its true deployment benefits, which motivates for the necessity of developing practical routing protocols for multihop underwater optical wireless sensor networks (UOWSNs). This paper sheds light on the existing state-of-art UOWC routing protocols, the majority of which requires centralized implementation with large end-to-end delay. The article further proposes routing algorithms which can be implemented in a distributed fashion across the multi-hop links, with a reasonable amount of information exchange. The merits of the proposed algorithms are particularly highlighted through illustrative simulations, which show how the proposed strategies outperform the classical protocols, both in terms of reliability and end-to-end latency. Finally, the paper shows how the proposed distributive routing protocols achieve ultra-reliable low-latency underwater communications. Index Terms-Underwater optical wireless communications, underwater optical wireless sensor network, routing protocols, distributed routing protocols, Ultra-reliable low-latency communication.

An Overview of Machine Learning-Based Techniques for Solving Optimization Problems in Communications and Signal Processing

“…Utilizing heuristic search for such an optimization problem causes the latency of the network to go below the requirement of URLLC. Moreover, the objective function of the optimization problem does not have a closed-form expression; see [88] and references therein. In other words, the objective function which aims to minimize the bit-error-rate is expressed in a recursive fashion, which adds up to the complexity of the problem.…”

Accurate 3-D Localization of Selected Smart Objects in Optical Internet of Underwater Things

“…Unlike, the acoustic-based underwater networks, Optical waves in O-IoUT are a promising transmission carrier for enabling ultra-reliable low latency communications, due to their ability to achieve broadband links with high data rate (Gbps) and low latency [51]. For instance, the average propagation speed of acoustic waves in water is 1500 m/s, which has profound implications on synchronization and localization in an underwater environment.…”

An optimal cluster‐based routing algorithm for UCBSNs

“…They either present shortcomings in the CH election criteria through ignoring important factors such as the nodes' mobility and the distance between the CH and the sink, or in the cluster formation phase through allowing the creation of large clusters which would quickly drain the energy of the CH, or in the routing operation through adopting single-hop rather than multi-hop data routing. Some other articles, like 7,8 propose distributed routing algorithms which are be implemented over multi-path links. However, in this paper, we focus on cluster based routing schemes rather than flat multi-hop routing operations, since cluster-based routing is proven to be very efficient in prolonging CBSN lifetime through spreading the energy consumption equally among different nodes.…”

“…The end-to-end BER simulation results are presented in Figure 3. BER is computed using the equations presented in, 7 assuming an angle of 30 • between the transmitter and receiver trajectory. Results show that the proposed scheme results in the lowest BER since it adopts multi-hop intra-and inter-cluster routing operations; the data will be therefore transmitted over shorter distances leading to lower BER.…”