Underwater Acoustic Communications and Networking: Recent Advances and Future Challenges

Abstract

A B S T R A C TThe past 30 years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. Continued research over the years has resulted in improved performance and robustness as compared to the initial communication systems. In this paper, we aim to provide an overview of the key developments in point-to-point communication techniques as well as underwater networking protocols since the beginning of this decade. We also provide an insight into some of the open problems and challenges facing researchers in this field in the near future.protocols for such networks. In this paper, we do not attempt to provide an exhaustive survey of all research in the field, but instead concentrate on ideas and developments that are likely to be the keystone of future underwater communication networks. II. Underwater CommunicationsHigh-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In the initial years, rapid progress was made in deep water communication, but the shallow water channel was considered difficult. In the past decade, significant advances have been made in shallow water communication.

Performance Evaluation of an Underwater Propagation Delay-Aware Medium Access Control Protocol

“…지상 환경에서 신호가 전파될 때 소 요되는 전파 지연과 달리 수중 환경에서의 음향 신 호의 전파 지연은 상당히 길게 된다. [1][2][3][4] Chitre et al [5] 은 수중 음향 통신과 네트워킹 및 매체 접근 제어 프 로토콜에 대해 발표하였다. Fullmer와 Garcia-LunaAceves [6] 은 FAMA(Floor Acquisition Multiple Access) 를 발표하였고, Molins와 Stojanovic [7] 은 수중 음향 네트워크를 위해 슬롯 FAMA를 발표하였다.…”

Comprehensive Study of Acoustic Channel Models for Underwater Wireless Communication Networks

“…Authors in [5] proposed a Rayleigh fading channel model for shallow water but there is still no single model available as accepted by the entire research community which is applicable for shallow waters [6]. In [7], a simple stochastic channel model is proposed and no experimental results are presented.…”

“…They are: turbulence, waves, shipping and thermal noise. The overall power spectral density of the ambient noise is expressed in dB and is given by [19] The SNR of an underwater acoustic signal at a receiver can be computed in dB by the passive sonar equation [6] as follows:…”

A Possible Development of Marine Internet: A Large Scale Cooperative Heterogeneous Wireless Network

“…But due to many challenges for realizing efficient underwater networking [2][3][4][5][6], a single underwater wireless network can only cover a small area and is often isolated from each other. This is due to the fact that the currently popular underwater communication medium is acoustic wave, which can only provide low transmission rates with large propagation delay [7][8][9][10]. Another underwater communication medium is blue/green laser, which can provide much higher transmission rates with shorter propagation delay but can only propagate well over shorter distance [11].…”