Conference PaperPDF Available

Abstract and Figures

Our earth the only planet where water could be found and covered more than seventy percent with it. Monitoring different phenomenal activities in an underwater environment, such as environmental impact surveillance, marine life, oil and gas exploration is essential in underwater. In this regard, underwater wireless communication (UWC) has become a significant field. Optical, acoustic and electromagnetic waves have been widely used for data transmission in UWC. Investigation of possible UWC techniques has an influential impact on wireless communications. Nowadays, UWC is being used for experimental observation, oceanographic data collection and analysis, underwater navigation, disaster prevention and early detection warning of a tsunami. This work presents an overview, main initiatives and up-to-date contributions of the most widely used UWC techniques, i.e, underwater wireless optical, acoustic and electromagnetic communications. In addition, we summarize emerging technologies in the UWC, future research directions and recommendations using fifth generation (5G) communication techniques.
Content may be subject to copyright.
Underwater Communications: Recent Advances
Mohammad Furqan Ali, Dushantha Nalin K. Jayakody∗†, Tharindu D. Ponnimbaduge Perera,
Kathiravan Srinivasan, Abhishek Sharma§and Ioannis Krikidis
School of Computer Science and Robotics, National Research Tomsk Polytechnic University, RUSSIA
School of Postgraduate Studies, Sri Lanka Technological Campus, Sri Lanka
School of Information Technology and Engineering, Vellore Institute of Technology, INDIA
§Department of Electronics Communication Engineering, The LNM Institute of Information Technology, INDIA
Department of Electrical and Computer Engineering, University of Cyprus, Cyprus
Abstract—Our earth the only planet where water could be
found and covered more than seventy percent with it. Monitoring
different phenomenal activities in an underwater environment,
such as environmental impact surveillance, marine life, oil and
gas exploration is essential in underwater. In this regard, under-
water wireless communication (UWC) has become a significant
field. Optical, acoustic and electromagnetic waves have been
widely used for data transmission in UWC. Investigation of
possible UWC techniques has an influential impact on wireless
communications. Nowadays, UWC is being used for experi-
mental observation, oceanographic data collection and analysis,
underwater navigation, disaster prevention and early detection
warning of a tsunami. This work presents an overview, main
initiatives and up-to-date contributions of the most widely used
UWC techniques, i.e, underwater wireless optical, acoustic and
electromagnetic communications. In addition, we summarize
emerging technologies in the UWC, future research directions
and recommendations using fifth generation (5G) communication
Index Terms—Underwater wireless acoustic communication,
Underwater electromagnetic communication , Underwater optical
communication, 5G wireless communication.
Global warming has become an issue for several decades.
In rising of global warming, the polar ice caps melt gradually
cause of rising sea level. Hence, the importance of observing
ocean environmental activities such as oceanographic data
collection, water sampling, etc., has gradually increased with
time variation. Underwater Wireless Communication (UWC)
supports surveillance of coastal securities, especially for mil-
itary purposes and commercially for investigation of natural
resources in underwater environment. Moreover, it also helps
for mapping and discovering the unknown regions of under-
water. Nowadays, UWC is being used for experimental obser-
vation, data collection, and analysis, underwater navigation,
disaster prevention and early detection warning of tsunami [1].
Optical, acoustic and electromagnetic (EM) wireless carriers
are considered to envisage UWC in underwater applications.
Deploying UWC techniques in an unexplored water medium
are highly challenging as compared to terrestrial wireless
communication [2]. However, the quality and reliability of data
transmission in shallow and deep water are dependent on the
physical characteristics of the water channel [3]. The Quality
of Service (QoS) of UWC, depends on the physicochemical
properties of water medium and physical characteristic of
optical, acoustic and EM waves. UWC plays a significant role
in deployed underwater applications, which has an influential
impact on the wireless network. The deployment of commu-
nication network setup in underwater systems consist of fixed
and anchored sensor nodes with the seabed, floating unmanned
underwater vehicle nodes (UUVs) or autonomous underwater
vehicle (AUVs), signal receiver processing towers, floating
devices (buoy), submarines, ships and onshore base stations
EM waves in radio frequency (RF), 3Hz to 3 kHz frequency
range is capable for high data acquisition and transmission
in shallow water over short distances and usually attenu-
ated easily by seawater [4]. On the other side, acoustic
waves are affected by different propagation factors due to
ambient noise, external interference, water-surface geomet-
rical expansion, attenuation, multi-path effects, and Doppler
spreading. Optical waves have high bandwidth, but affected
by absorption, scattering and different level of temperature
in underwater. Underwater wireless optical communication
(UWOC) has less explored and somewhat challenging to de-
ploy than acoustic propagation in underwater [5]. The existing
Underwater wireless acoustic communication (UWAC) has the
limited performance of low bandwidth, latency and multi-path
propagation in an underwater medium. The maximum data
acquisition in UWAC is roughly 100 kbps for short distances
while 10 kbps over long distances. The possible bandwidth
with respect to propagation distance in UWAC are listed down
in Table I.
The main purpose of this survey is to understand the main
characteristics and existing features of UWC. This work has
an overview of possible UWC techniques and up-to date
literature. The remaining structure of this paper as follows:
In section II, we discuss the main deployable techniques
of UWC towards the next generation of wireless network.
Underwater wireless RF communication (UWRFC) and related
issues are described in section III. Underwater wireless optical
communication (UWOC) has been widely discussed in section
IV. In section V, underwater wireless acoustic communication
(UWAC) and it’s issues are discussed. The paper contributes
emerging communication techniques proposed by recent re-
search in section VI. Finally, we conclude the paper in section
Classified Prop-
agation distance
Possible range
data rate
Very Sort Less than 0.1 More than
short 0.1 to 1 20 to 50 30
Medium 1 to 10 Up to 10 10
Long 10 to 100 2 to 5 5
Very long more than 100 Less than 1 600
5G wireless network will be the future networking technique
in wireless communications with extremely low latency and
high data rate [9] [10]. A high range acoustic communication
through orthogonal frequency-division multiplexing (OFDM)
techniques has been discussed in [11]. The authors [3] dis-
cussed UWC techniques and its’ related issues along with the
UWC emerging technologies. Filter bank multicarrier (FBMC)
and generalized frequency division multiplexing (GFDM) are
the latest promising techniques for 5G applications in un-
derwater environment. GFDM is a multicarrier scheme that
based on time and frequency, which is derived from filter bank
approach [12]. FBMC also addresses both time and frequency
dispersions that should be constructed by using prototype filter.
The parametric constraints should matches channel properties
[13]. An experimental work on GFDM technique towards
underwater 5G communication systems based on multi-carrier
filter bank has been discussed in [12]. The concept of adopting
MIMO-OFDM for underwater acoustic channel and using
FBMC modulation technique towards 5G wireless network
investigated in [14].
A. Types of water in UWC
The seawater has been categorized into three different cate-
gories in UWC, i.e, clearest, intermediate and murkiest water
[15]. The clearest water is the most transparent water, which
could be found in Atlantic and Mid-Pacific ocean. Secondly,
intermediate water can be found in North Pacific ocean. The
murkiest water can be found typically in the Northern Sea and
Eastern Atlantic ocean. Due to optical propagation, seawater
has been divided into four categories due to optical inherent
properties (IOP) [6] i.e. pure seawater, clear ocean water,
coastal ocean water, turbid harbor and estuary water. Typical
values of absorption and scattering coefficients in different
waters are listed-down in Table II.
Absorption and scattering of signals play a major role in
deciding QoS in UWC. In optical signal propagation, the
scattering losses arise due to the high particle concentration
in clear ocean water while the absorption and other major
Description of water
for UWC
a(λ) b(λ)bb(λ) c(λ)
Pure sea water 0.053 0.003 0.0006 0.056
Clear Ocean water 0.069 0.08 0.001 0.15
Coastal Ocean water 0.088 0.216 0.0014 0.305
Turbid Harbor water 0.295 1.875 0.0076 2.17
Fig. 1. Acoustic and RF signal propagation between underwater sensor nodes
and terrestrial offshore station
losses occur in pure seawater. The higher concentration of
suspended particles in ocean water support to scattering and
absorption phenomena and affect to signal propagation. The
highest concentration of particles could be found in turbid
harbor and estuary water than pure and clear ocean waters.
EM waves used for signal transmission between underwater
and terrestrial communication platforms [16]. EM waves cov-
ers frequency ranges from few kHz to 1 GHz [17]. EM waves
propagation setup deploy for shallow water over tens of meter
called by RF buoyant underwater communication [6]. The
possibility of RF signal propagation is higher in shallow water
than deep ocean water. The oceanic water offers high con-
ductance which could be seriously affected to electromagnetic
wave propagation [3]. Thus, very less possibility is available
to establish communication over long distance in the under-
water environment, with ultra-high frequency and very high-
frequency ranges (VHF and UHF), or even in high-frequencies
(HF). The electromagnetic waves attenuation considered to
be lower enough to achieve expected communications over
several kilometers in underwater environment [4]. Thus, the
multiple-path propagation could be an additional benefit for
underwater signal transmission in inland water reservoirs, i,e
lakes, rivers, etc. from submerged communication nodes to
Types of Tech-
Distance Propagation
Frequency Bandwidth Data
Attenuation Affecting factors deter-
mine channel quality
RF Very short dis-
tance (Up to 10
2.255x10830-300 Hz MHz Mbps Frequency and
dependent (3.5-5
Conductivity and permi-
tivity of channel
[2] [4]
[7] [6]
Optical waves Short distances
(Up to 100 m)
same as RF
MHz Gbps 0.39 dB/m (Ocean)
and 11 dB/m (Turbid
Absorption, scattering,
turbidity, suspended and
organic matter of channel
[2] [4]
[7] [6]
Acoustic Long distance
(Up to 20 km)
1500 10-1 kHz Hz kbps Distance and
frequency dependent
(0.1-4 dB/m)
Absorption, scattering,
pressure, temperature and
salinity of water medium
[2] [4]
[7] [6]
onshore base stations [18]. In UWRFC, signals experience
high attenuation than in terrestrial communication.
In UWRFC, EM wave propagation depends on underwater
environment. The physical properties of the water, i.e., salinity,
conductivity, and temperature affect electromagnetic propa-
gation in underwater [19]. In seawater, the average value of
conductivity approximately 4 mhos/m, which is doubled in the
magnitude of conductivity in freshwater [6]. The absorption
coefficient in seawater can be expressed as [19].
α(f) = pπσµ0f, (1)
where radio frequency denotes by fand σrepresents the
conductivity of the water. The vacuum permeability describes
by µ04π107H/m. The value of µ0is almost equal in fresh
and seawater [4]. A typical channel model transfer function for
different channel parameters is widely discussed in [19].
A. Main issues in underwater RF communication
EM waves are affected by several factors depend on the
water properties, such as density level, which can vary with
temperature, high permittivity, electrical conductivity, and
salinity. In addition EM waves also affected by turbidity in
underwater and by the various types of noises. In UWRFC,
multi-path propagation is the most influential phenomena that
has a direct impact on RF propagation from water to air. The
refraction angle and losses also have a consideration in RF
signaling to cross the air-water boundary by patching through
an antenna [4]. Electromagnetic waves used for a limited range
of communication in underwater, which could be raise for over
long ranges by implementing a specific design of an antenna.
A large size antenna is required for RF signal propagation
between terrestrial and underwater communication. The mag-
netic coupled loop types of antennas are the most reliable for
practical solutions. An another option is to use an electric
dipole antenna for lateral electromagnetic waves that has been
discussed in [18]. In the deployment of UWRFC propagation
scheme, major factors to be considered are high data rate, the
antenna design and transmitting power strength.
UWOC has many distinct properties during propagation
at different frequencies over different ranges in dissimilar
water mediums [8]. The light speed might be around four to
five times stronger and higher in magnitude than propagation
speed of acoustic waves in fluids [4]. The sea water offers a
conductive property for RF propagation and dielectric proper-
ties for optical signal propagation [4]. Optical communication
is affected by scattering, dispersion, line of sight (LOS),
fluctuation in temperature and by physiochemical properties
of the water. In dielectric medium, the possibility to achieve
high data rates through UWOC technology as compared to
UWRFC, where the range of propagation limited up to tens of
meters [4]. In addition, the negotiation of Doppler effect can be
obtained in optical communications as compare to competitive
schemes, i.e., EM, acoustic.
According to the environmental conditions, the sea water
has been categorized into two specific categories, inherent
optical properties (IOP) and apparent optical properties (AOP)
in respect with optical propagation. IOP is medium dependent,
while AOP is light source dependent [20]. In optical propa-
gation, photons change their direction due to scattering and
the possibility of scattered photons originated by salt ions in
pure water [20]. In UWOC propagation, the beam attenuation
coefficient is directly related to the intensity and separation
distance of light sources. The light intensity at receiver end
can be expressed as [21].
where I0and Iare the light intensities both of transmitter
ends and receiver, ddenotes the distance between transmitter
and receiver.
A. Noises in underwater optical communication
There are different types of noises in UWOC such as
quantum shot noise, optical excess noise, optical background
noise, photo-detector dark current noise and electronic noise
The Quantum noise: This type of noise occurs due to
receive random variation of photons by optical receiver.
The Optical excess noise: The Optical excess noise
caused due to transmitter imperfection.
The Background noise: In this type of noise the back-
ground consider as a blackbody radiation in underwater
Fig. 2. Illustration of Underwater optical sensor network clusters with
terrestrial RF based station
whose primary source is the refracted sunlight from the
water surface. Due to this phenomena, the solar and
blackbody radiation background noises occur.
The Photo-detector dark current noise:- Due to electrical
current leakage from photo-detector this kind of noise
B. Main Issues in optical communication
Absorption and scattering are the two crucial effects that
affect the propagation of optical waves in underwater [7]. We
can understand the simple phenomena of these two factors
by the geometrical model of a water element that has shown
in Fig. 3. If the input beam of light strength Pi(λ), the
small fraction of incident beam Pa(λ) absorbed and fraction
Ps(λ) scattered by water element. The unaffected result Pc(λ)
passing through water element whose volume is δV and
thickness δr respectively. According to energy conservation
balancing, the absorption and scattering phenomena can be
described as [6].
Pi(λ) = Pa(λ) + Ps(λ) + Pc(λ).(3)
The overall attenuation in underwater coefficient c(λ) can
be expressed as [7].
c(λ) = a(λ) + b(λ).(4)
The values of a(λ) and b(λ) in different water medium could
be found from Table II.
UWAC is an alternative communication technique which
can be used for longer distance communication than UWRFC
and UWOC. However it has a limited range of propagation and
is affected by strong attenuation and water turbidity. Acoustic
waves propagation offers low frequency, bandwidth and low
speed around 1500 m/s. The propagation of acoustic waves
is faster in normal water than cold water [3]. Generally, the
speed increase of acoustic waves about 4 m/s, due to rising of
Fig. 3. Optical wave scattering and absorption phenomena in underwater as
given in [6] [8]
1C temperature in water. According to the acoustic waves
propagation range, the water channel has been categorized
very short, short, medium, long and very long propagation
distances [6]. In Table I, mentioned the different bandwidth
ranges according to the propagation range. An acoustic model
for sound speed profile (SSP) has been discussed for under-
water communication environments with 1 km of water depth
c= 1449.2+4.6T0.055T2+ 0.00029T3
+(1.34 0.01T)(S35) + 0.016z, (5)
where cdenotes acoustic wave speed and Tis channel
temperature, Srepresents the salinity of water and water
depth denotes by z. Thus, the acoustic waves speed is a
function of channel temperature, depth and salinity of water
which can be proportional to water temperature, salinity and
depth of water medium [24]. Due to high absorption and
frequency, wave energy converts into heat energy. Similarly,
longer propagation ranges lead to high absorption losses [25].
The absorption coefficient is the sum of absorptivity and
contribution of chemical reaction by the water medium [26]
[27]. Similarly, scattering loss occurs due to obstacles during
acoustic wave propagation. These obstacles can be consider
by the disturbance at sea surface, existing fixed or movable
objects at the bottom of sea. Spreading and absorption losses
contribute path loss, whose explained by a simplified model
expressed by [25] [28].
10 log A(l, f ) = 10 log (A0) + 10klog (l)
+(l)10 log a(f, S, T , c, p, H, z),(6)
where ldenotes the distance (in meters) or propagation range
between transmitter and receiver, fis the frequency range
(in kHz) and kdenotes the spreading factor. For cylindrical
spreading the value of k= 1, while for spherical spreading
k= 2, the value of k= 1.5can be taken for experimental
spreading [25]. Log A0is called normalizing factor which is
the inverse of transmitted power. The variables are represent-
ing the attenuation coefficient (in dB/meter), depend on envi-
ronmental channel conditions [28]. The variable Srepresents
salinity (in ppt), temperature denotes by T(in degree Celsius),
and cis the speed of acoustic wave propagation (in m/s), z
and Hare showing the depth of water in meters. The path
losses expand when the frequency fand separation distance
dbetween transmitter and receiver increase.
A. Most common Issues in underwater acoustic propagation
The main issues in underwater acoustic propagation that
affect communication links through man-made noises, path
and multi-path losses, Doppler spread, high and variable prop-
agation delay. Above mentioned losses and factors determined
the temporal and spatial variability of the acoustic channel
that cause of limited communication range, frequency and
bandwidth of acoustic communication link. The following
factors are effective issues on acoustic communication.
Losses: The main factors can be taken into an account
while signal propagation energy losses, absorption and
scattering loss respectively.
Man-made and ambient noise: Ambient noise related to
hydrodynamics properties of water such as an underwater
thunderstorm, water movement, water tides, water bub-
bles and fain, wind, rain and biological phenomena. The
ambient noise losses up to 26 dB/km [29]. Man-made
noises produced by machine tools such as pumps, power
plants, submarines and ships etc.
Attenuation: Attenuation occurs by absorption of the
acoustic energy that transforms into heat, scattering,
refraction reverberation phenomenon, and dispersion.
Acoustic waves attenuation is directly proportional to the
frequency of waves and depth of water medium.
Absorption: The energy conversion phenomena of acous-
tic waves in another form of energy by chemical charac-
teristics of the water channel.
Geometric expansion: Geometric expansion is a spreading
experience and function of energy loss in acoustic waves
over the large area. When the acoustic pulse propagates
from source of origin and covers a large water area, the
wave energy per unit area become smaller.
Path and multi-path propagation losses produced by the
degradation of acoustic waves, generates Inter-Symbol
Interference (ISI). The multi-path propagation are the
geometrical constraints and configuration link dependent.
In Vertical channels develops a little time dispersion but
through water layers, it has a long multi-path spread,
which is depends on water depth.
Doppler frequency spread is an important and noticeable
factor in UWAC, due to a low destruction in the perfor-
mance of digital communication and transmission at high
data rate [8].
A. Energy Harvesting
Energy harvesting (EH) is an approach to capturing and
transformed usefulness energy into usable electric power
where energy requires in terms of heat, vibration and RF
signals. Underwater wireless sensor network (UWSNs) is an
emerging technique to establish reliable data although required
high energy constraints. The wireless power transmission
(WPT) technique is promising EH technique. In WPT the
Fig. 4. Emerging Underwater Wireless Technologies
nodes capable to charge their own batteries sources through
electromagnetic radiation in remote networking area [30].
WPT offers a good performance for short distances while it
depends on application requirement for long distance. The
authors [30] proposed simultaneous information and power
transfer EH technique (SWIPT) that enables to transfer in-
formation and power simultaneously. These investigated tech-
niques support to improve efficiency of system.
B. Massive MIMO adaptive Underwater Communication
Massive multi-input-multi-output (MIMO) supports under-
water acoustic communication through large number of hy-
drophones array. It also support the various types of multime-
dia communication contents in real time activities and audio-
video conferencing [31]. Massive MIMO is an auspicious
solution that support to improve throughput, capacity and
energy efficiency of UWC system in the future.
C. mmWaves enabling Underwater Communication
Due to high demand of improving communication network-
ing capacity, mmWaves are an alternative solution to support
underwater communication. These waves offer likely similar
characteristics to the optical wireless signals. Hence mmWaves
are considering to offer high bandwidth transmission and
efficiency to improve communication performances [32]. The
waves are capable to provide up to 10 gbps data rates which
is the solution of hybrid communication [33].
D. Non-Orthogonal Multiple Access (NOMA) as an emerging
wireless carrier
Non-Orthogonal multiple access (NOMA) offers desirable
communication benefits and a promising multiple access tech-
nique. It allows to connect multiple users simultaneously
and minimize delay. The future acpect of NOMA expected
allocation schemes in Underwater acoustic networks architec-
ture (UWASNs) and equal transmission times (ETT) power
allocation which are capable to prevent the wasteful resources
generation in underwater environment that proposed for the
future perspectives [34].
E. Internet of Underwater Things (IoUTs)
Internet of things is an emerging technology that offers
to connect devices wirelessly. The integration of Internet
of Underwater Things (IoUTs) plays a significant role to
allow data exchange between UWSNs to the base station
in underwater environment. IoUTs provide an opportunity to
observation of marine life and understanding of underwater
habitats [35].
UWC technology enables a platform to build up a network
connection between underwater devices with offshore based
station. The main motto of this paper to provide an overview
and challenges posed by the peculiarities of underwater com-
munication technologies with particular reference to monitor-
ing applications in water medium. The different water channels
and communication links have crucially difficult properties
and challenges. The technologies discussed, the possible so-
lutions and grasp to deploy underwater wireless acoustic,
underwater wireless electromagnetic and underwater optical
wireless communication technologies. The main outline of
this paper to encourage research efforts and development of
new advanced communication techniques. This paper has been
contributed and providing a survey of the technical issues
and challenges in underwater networks and communication
of entire technologies towards the next generation wireless
networking system.
[1] M. Uysal, C. Capsoni, Z. Ghassemlooy, A. Boucouvalas, and E. Udvary,
Optical wireless communications: an emerging technology. Springer,
[2] S. Zhou and Z. Wang, OFDM for underwater acoustic communications.
John Wiley & Sons, 2014.
[3] L. Lanbo, Z. Shengli, and C. Jun-Hong, “Prospects and problems
of wireless communication for underwater sensor networks,” Wireless
Communications and Mobile Computing, vol. 8, no. 8, pp. 977–994,
[4] C. Gussen, P. Diniz, M. Campos, W. A. Martins, F. M. Costa, and J. N.
Gois, “A survey of underwater wireless communication technologies,”
J. Commun. Inform. Sys, vol. 31, no. 1, 2016.
[5] F. Hanson and S. Radic, “High bandwidth underwater optical commu-
nication,” Applied optics, vol. 47, no. 2, pp. 277–283, 2008.
[6] H. Kaushal and G. Kaddoum, “Underwater optical wireless communi-
cation,” IEEE access, vol. 4, pp. 1518–1547, 2016.
[7] Z. Zeng, S. Fu, H. Zhang, Y. Dong, and J. Cheng, “A survey of
underwater optical wireless communications,” IEEE communications
surveys & tutorials, vol. 19, no. 1, pp. 204–238, 2017.
[8] N. Saeed, A. Celik, T. Y. Al-Naffouri, and M.-S. Alouini, “Underwater
optical wireless communications, networking, and localization: A sur-
vey,” arXiv preprint arXiv:1803.02442, 2018.
[9] T. S. Rappaport, S. Sun, R. Mayzus, H. Zhao, Y. Azar, K. Wang, G. N.
Wong, J. K. Schulz, M. Samimi, and F. Gutierrez Jr, “Millimeter wave
mobile communications for 5g cellular: It will work!” IEEE access,
vol. 1, no. 1, pp. 335–349, 2013.
[10] M. Agiwal, A. Roy, and N. Saxena, “Next generation 5g wireless
networks: A comprehensive survey,” IEEE Communications Surveys &
Tutorials, vol. 18, no. 3, pp. 1617–1655, 2016.
[11] J. Huang, J. Sun, C. He, X. Shen, and Q. Zhang, “High-speed underwater
acoustic communication based on ofdm,” in Microwave, Antenna, Prop-
agation and EMC Technologies for Wireless Communications, 2005.
MAPE 2005. IEEE International Symposium on, vol. 2. IEEE, 2005,
pp. 1135–1138.
[12] J. Wu, X. Ma, X. Qi, Z. Babar, and W. Zheng, “Influence of pulse
shaping filters on papr performance of underwater 5g communication
system technique: Gfdm,” Wireless Communications and Mobile Com-
puting, vol. 2017, 2017.
[13] P. Amini, R.-R. Chen, and B. Farhang-Boroujeny, “Filterbank multicar-
rier for underwater communications,” in Communication, Control, and
Computing (Allerton), 2011 49th Annual Allerton Conference on. IEEE,
2011, pp. 639–646.
[14] A. Aminjavaheri and B. Farhang-Boroujeny, “Uwa massive mimo com-
munications,” in OCEANS’15 MTS/IEEE Washington. IEEE, 2015, pp.
[15] M. Lanzagorta, “Underwater communications,” Synthesis Lectures on
Communications, vol. 5, no. 2, pp. 1–129, 2012.
[16] A. I. Al-Shamma’a, A. Shaw, and S. Saman, “Propagation of electromag-
netic waves at mhz frequencies through seawater,” IEEE Transactions
on Antennas and Propagation, vol. 52, no. 11, pp. 2843–2849, 2004.
[17] M. Rhodes, “Electromagnetic propagation in sea water and its value in
military systems,” in SEAS DTC Technical Conference, 2007, pp. 1–6.
[18] X. Che, I. Wells, G. Dickers, P. Kear, and X. Gong, “Re-evaluation of rf
electromagnetic communication in underwater sensor networks,” IEEE
Communications Magazine, vol. 48, no. 12, pp. 143–151, 2010.
[19] A. Zoksimovski, D. Sexton, M. Stojanovic, and C. Rappaport, “Un-
derwater electromagnetic communications using conduction–channel
characterization,” Ad Hoc Networks, vol. 34, pp. 42–51, 2015.
[20] J. A. Simpson et al., “A 1 mbps underwater communications system
using leds and photodiodes with signal processing capability,” 2008.
[21] J. W. Giles and I. N. Bankman, “Underwater optical communications
systems. part 2: basic design considerations,” in Military Communica-
tions Conference, 2005. MILCOM 2005. IEEE. IEEE, 2005, pp. 1700–
[22] S. Jaruwatanadilok, “Underwater wireless optical communication chan-
nel modeling and performance evaluation using vector radiative transfer
theory,IEEE Journal on Selected Areas in Communications, vol. 26,
no. 9, 2008.
[23] F. B. Jensen, W. A. Kuperman, M. B. Porter, and H. Schmidt, Compu-
tational ocean acoustics. Springer Science & Business Media, 2011.
[24] J. R. Apel, Principles of ocean physics. Academic Press, 1987, vol. 38.
[25] M. Stojanovic, “On the relationship between capacity and distance in
an underwater acoustic communication channel,” ACM SIGMOBILE
Mobile Computing and Communications Review, vol. 11, no. 4, pp. 34–
43, 2007.
[26] Y. Y. Al-Aboosi, M. S. Ahmed, N. S. M. Shah, and N. H. H. Khamis,
“Study of absorption loss effects on acoustic wave propagation in
shallow water using different empirical models,” 2006.
[27] M. A. Ainslie and J. G. McColm, “A simplified formula for viscous and
chemical absorption in sea water,The Journal of the Acoustical Society
of America, vol. 103, no. 3, pp. 1671–1672, 1998.
[28] M. C. Domingo, “Overview of channel models for underwater wireless
communication networks,” Physical Communication, vol. 1, no. 3, pp.
163–182, 2008.
[29] J. Loo, J. L. Mauri, and J. H. Ortiz, Mobile ad hoc networks: current
status and future trends. CRC Press, 2016.
[30] T. D. P. Perera, D. N. K. Jayakody, S. K. Sharma, S. Chatzinotas, and
J. Li, “Simultaneous wireless information and power transfer (swipt):
Recent advances and future challenges,IEEE Communications Surveys
& Tutorials, vol. 20, no. 1, pp. 264–302, 2017.
[31] B. Li, J. Huang, S. Zhou, K. Ball, M. Stojanovic, L. Freitag, and P. Wil-
lett, “Mimo-ofdm for high-rate underwater acoustic communications,”
IEEE Journal of Oceanic Engineering, vol. 34, no. 4, pp. 634–644,
[32] M. Leeson and M. Higgins, “Optical wireless and millimeter waves
for 5g access networks,” in The Fifth Generation (5G) of Wireless
Communication. IntechOpen, 2018.
[33] C. DeMartino. (2017) Millimeter Waves are millimeter
waves the wave of the future? [Online]. Available:
[34] J. Cheon and H.-S. Cho, “Power allocation scheme for non-orthogonal
multiple access in underwater acoustic communications,” Sensors,
vol. 17, no. 11, p. 2465, 2017.
[35] C.-C. Kao, Y.-S. Lin, G.-D. Wu, and C.-J. Huang, “A comprehensive
study on the internet of underwater things: Applications, challenges, and
channel models,” Sensors, vol. 17, no. 7, p. 1477, 2017.
... The extinction coefficient is the total sum of absorption a(λ) and scattering b(λ) of the optical beam photons in underwater environment i.e, c(λ) = a(λ) + b(λ). The typical values of a(λ) and b(λ) in different types of water medium are given in Table I [20]. On the other hand, in FSO link the signals also affected by atmospheric conditions. ...
... The attenuation coefficient h F SO l (λ, d) depends on the LOS distance d rd between nodes, distribution of scattering signals and the utilized wavelength (λ). Thus, the underwater attenuation coefficient and terrestrial basis FSO link attenuation coefficients according to Beer Lambert's law, can be expressed by (3) and (4) The typical values of absorption, scattering and extinction coefficients wavelength-dependent at 450nm blue light in different water mediums [20] ...
... Similarly, for the SM2 the average BER can be given as the closed-form expression (20) by replacing the values of (15) and (16) in (18) then we get (20) ...
Conference Paper
Full-text available
Underwater wireless communication (UWC) has become a significant approach that is used to explore the aqueous mediums through various underwater applications. It is also noteworthy that the collected data from underwater has to transmit to inland data fusion centers for further investigation and operating instructions need to transmit from the inland center to autonomous underwater vehicles (AUVs) to operate as per the real-time requirements. Therefore, a hybrid terrestrial and UWC setup is required in most of the underwater military and commercial applications. In this study, the two different dual-hop up-link hybrid underwater and terrestrial cooperative communication systems have been investigated. A floating buoy works as a relay node to assist information transmission from AUV and regenerated then forward information with the terrestrial-based station (BS). The AUV transmits information through visible light communication (VLC) link with the relay node. Moreover, RF and Free-space optics (FSO) are used as a potential candidate for terrestrial communication between relay and destination of the proposed system models. Numerical results show that the VLC-FSO combination has the superior bit-error-rate (BER) performance compare with the VLC-RF setup in low SNR conditions regardless of the water mediums.
... Furthermore, there is a separating distance between the entities concerned. The second term of the right hand side in (23) and (24) describe the ratio of the distance between AUVs to the distance between entities and the computing entity. ...
... In Table 2, the values on the separating distance are used with regard to the performance evaluation are motivated by [24,25]. The simulation considers one underwater data centre as shown in Fig. 1. ...
Full-text available
Underwater data acquisition entities acquire big data that are processed aboard terrestrial data centres. However, processing the big data aboard terrestrial computing entities involves high latency data transfer. In addition, the processing of data in a terrestrial environment is challenging when there is inadequate edge node capacity. These challenges are addressed here. The paper proposes the heterogeneous edge computing paradigm to realize low latency transfer of increasing underwater big data. This is realized via the use of underwater computing entities instead of terrestrial computing entities for processing acquired big data. The proposed heterogeneous edge computing paradigm presents the multi-mode automated teller machine (ATM) as low cost terrestrial edge network entity. The multi-mode ATM is suitable when edge nodes have inadequate computing capacity. Performance evaluation shows that the use of underwater computing entities instead of terrestrial computing entities (existing work) enhances network performance and related capital costs. The number of hops, computing entity access latency and required autonomous underwater vehicle acquisition costs by an average of (5.3–88.4)%, 63.5% and (31.8–95.4)%, respectively. Evaluation shows that the use of the multi-mode ATM in the context of terrestrial cloud computing reduces the number of hops and latency by 44.4% and 37.3% on average, respectively.
... The propagation speed is very high with a range of 10^7 m/s, rate of transmitting data in the range of Mb/s. The communication range for EM wave is less than 10 m [2]. ...
... In dissipative medium  is given by  = jj' + eff (2) where  is angular frequency,' is electrical permittivity & eff is effective conductivity [3]. ...
Full-text available
The research in underwater wireless communication is attracting and leading to increased attention due to its numerous applications mainly for military & commercial fields. There exists enormous major challenges in the field of submerged communication or communication in underwater namely: Finite bandwidth, delay in propagation, less data rate, more BER (Bit Error Rate), Doppler spreading, High ambient noise etc. Underwater wireless communication is based on three types of waves, these are EM wave, acoustic wave & optical wave. Each type of wave propagation has its advantage & disadvantage. In the present review paper, mechanism of RF communication, acoustic communication & optical communication has been discussed in details & also differentiated the three communication based on various parameters such as attenuation, bandwidth, distance, propagation speed, latency, frequency etc. The mechanism of acoustic modem & its components has also been presented. The study will help the researchers to focus on the research gaps & undertake research in the field vigorously.
... Acoustic waves are used for long-ranges transmissions approximately up to 15 − 20 km, but these waves cannot achieve high bandwidth signals undersea. Due to low frequency, bandwidth, speed, and additionally the received signals are delayed at the destination [264], [265]. ...
Full-text available
In recent years, underwater visible light communication (UVLC) has become a potential wireless carrier candidate for signal transmission in highly critical, unknown, and acrimonious water mediums such as oceans. Unfortunately, the oceans are the least explored reservoirs in oceanogeographical history. However, natural disasters have aroused significant interest in observing and monitoring oceanic environments for the last couple of decades. Therefore, UVLC has drawn attention as a reliable digital carrier and claims a futuristic optical media in the wireless communication domain. Counterparts of traditional communications, the green, clean, and safe UVLC support high capacity data-rate and bandwidth with minimal delay. Nevertheless, the deployment of UVLC is challenging rather than terrestrial basis communication over long ranges. In addition, UVLC systems have severe signal attenuation and strong turbulence channel conditions. Due to the fact that, this study provides an exhaustive and comprehensive survey of recent advancements in UVLC implementations to cope with the optical signal propagation issues. In this regard, a wide detailed summary and future perspectives of underwater optical signaling towards 5G and beyond (5GB) networks along with the current project schemes, channel impairments, various optical signal modulation techniques, underwater sensor network (UWSN) architectures with energy harvesting approaches, hybrid communication possibilities, and advancements of Internet of underwater things (IoUTs) are concluded in this research.
Recently, the Internet of things (IoT) paradigm has proliferated all aspect of life. The improvements IoT has made in business and industry has raised the possibility of extending its use to underwater environments, which also impacts human life. Consequently, Internet of Underwater Things (IoUT) research is intensifying. As in IoT, to deploy a successful application in IoUT, an optimal communication network is required. However, underwater environments pose unique technical challenges for setting up such networks. The aim of these networks is to achieve optimal performance required for efficient and reliable transmission within IoUT. Communication is the lifeline of a network and involves the transmission of information along a medium or path. Thus, it is critical to understand the impact of underwater environment on IoUT communication. Overall, IoUT communication utilizes underwater and terrestrial equipment. We focus on underwater communication where the medium is water and information is transmitted as acoustic/sound signals. With respect to physical, Medium Access Control (MAC) and network layers, we investigate issues associated with designing optimal IoUT networks. The underwater ecosystem varies spatially with time so, knowledge of prevailing underwater regional profiles at any time is essential. Profiles enable the construction of necessary constraints that affect optimized performance of IoUT networks. We analyze the constraints imposed by different regional profiles of underwater ecosystem and their impact on optimal IoUT communication. These constraints affect performance goals required for successful IoUT network deployment. The analysis is useful for developing state-of-the-art IoUT communication strategies based on stochastic optimization models.
Full-text available
Crashing airplane could cause a falling black box inside ocean water. Generally, fast finding black box location pretty much needed to collect flight data history with unmanned underwater submarine vehicle such as called Unmanned Underwater Vehicle (UUV). Location of black box could be known from vertical and horizontal position of UUV. This horizontal positioning system in the air obtained from GPS. Meanwhile, underwater vertical positioning system using GPS is unreliable. Therefore, another alternative provided by this research is underwater vertical positioning system of UUV using hydrostatic pressure measurement to collect depth values. Design of vertical positioning UUV with hydrostatic pressure measurement that had been build consists of sensor module MS-5837, Arduino Uno Microcontroller, and data storage. This sub system is part of another three sub systems which is integrated become UUV data communication system. Depth values from output proceeded to the next subsystems and transmitted in water medium wirelessly. Final output of the system is position coordinate of UUV. Using experimental method on this research, it could generated proportional measurement between depth and hydrostatic pressure. It showed linearity of sensor by determination coefficient equals to 0.9984 and accuracy 97.44% from UNY’s swimming pool testing in 4,7 m depth and adding extrapolation until 10 m. Depth values is vertical position data for UUV. This research can be used as a reference to the next UUV development technologies. Keywords: Unmanned Underwater Vehicle, piezo resistive sensor, vertical positioning, accuracy, linearity, hydrostatic pressure, depth.
Full-text available
Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.
Full-text available
Efficient underwater acoustic communication and target locating systems require detailed study of acoustic wave propagation in the sea. Many investigators have studied the absorption of acoustic waves in ocean water and formulated empirical equations such as Thorp's formula, Schulkin and Marsh model and Fisher and Simmons formula. The Fisher and Simmons formula found the effect associated with the relaxation of boric acid on absorption and provided a more detailed form of absorption coefficient which varies with frequency. However, no simulation model has made for the underwater acoustic propagation using these models. This paper reports the comparative study of acoustic wave absorption carried out by means of modeling in MATLAB. The results of simulation have been evaluated using measured data collected at Desaru beach on the eastern shore of Johor in Malaysia. The model has been used to determine sound absorption for given values of depth (D), salinity (S), temperature (T), pH, and acoustic wave transmitter frequency (f). From the results a suitable range, depth and frequency can be found to obtain best propagation link with low absorption loss.
Full-text available
Initial efforts on Wireless Power Transfer (WPT) have concentrated towards long-distance transmission and high power applications. Nonetheless, the lower achievable transmission efficiency and potential health concerns arising due to high power applications, have caused limitations in their further developments. Due to tremendous energy consumption growth with ever-increasing connected devices, alternative wireless information and power transfer techniques have been important not only for theoretical research but also for the operational costs saving and for the sustainable growth of wireless communications. In this regard, Radio Frequency Energy Harvesting (RF-EH) for a wireless communications system presents a new paradigm that allows wireless nodes to recharge their batteries from the RF signals instead of fixed power grids and the traditional energy sources. In this approach, the RF energy is harvested from ambient electromagnetic sources or from the sources that directionally transmit RF energy for EH purposes. Notable research activities and major advances have occurred over the last decade in this direction. Thus, this paper provides a comprehensive survey of the state-of-art techniques, based on advances and open issues presented by Simultaneous Wireless Information and Power Transfer (SWIPT) and WPT assisted technologies. More specifically, in contrast to the existing works, this paper identifies and provides a detailed description of various potential emerging technologies for the fifth generation (5G) communications with SWIPT/WPT. Moreover, we provide some interesting research challenges and recommendations with the objective of stimulating future research in this emerging domain.
Full-text available
In this paper, we propose a power allocation scheme for non-orthogonal multiple access (NOMA) in underwater acoustic sensor networks (UWASNs). The existing terrestrial sum-rate maximization (SRM) power allocation scheme suffers from the degradation of the overall sum-rate in UWASNs due to wasteful resource created by unequal transmission times between each transmission path. To address this issue, we propose the equal transmission times (ETT) power allocation scheme, which can prevent wasteful resource generation by guaranteeing equal transmission times between each transmission path. ETT considers the number of packets waiting for transmission in the sender’s buffer for creating equal transmission times. Numerical results show that the proposed ETT outperforms SRM in terms of the overall sum-rate, while having nearly identical maximum sum-rate to the SRMs.
Full-text available
The Internet of Underwater Things (IoUT) is a novel class of Internet of Things (IoT), and is defined as the network of smart interconnected underwater objects. IoUT is expected to enable various practical applications, such as environmental monitoring, underwater exploration, and disaster prevention. With these applications, IoUT is regarded as one of the potential technologies toward developing smart cities. To support the concept of IoUT, Underwater Wireless Sensor Networks (UWSNs) have emerged as a promising network system. UWSNs are different from the traditional Territorial Wireless Sensor Networks (TWSNs), and have several unique properties, such as long propagation delay, narrow bandwidth, and low reliability. These unique properties would be great challenges for IoUT. In this paper, we provide a comprehensive study of IoUT, and the main contributions of this paper are threefold: (1) we introduce and classify the practical underwater applications that can highlight the importance of IoUT; (2) we point out the differences between UWSNs and traditional TWSNs, and these differences are the main challenges for IoUT; and (3) we investigate and evaluate the channel models, which are the technical core for designing reliable communication protocols on IoUT.
Full-text available
Generalized frequency division multiplexing (GFDM) is a new candidate technique for the fifth generation (5G) standard based on multibranch multicarrier filter bank. Unlike OFDM, it enables the frequency and time domain multiuser scheduling and can be implemented digitally. It is the generalization of traditional OFDM with several added advantages like the low PAPR (peak to average power ratio). In this paper, the influence of the pulse shaping filter on PAPR performance of the GFDM system is investigated and the comparison of PAPR in OFDM and GFDM is also demonstrated. The PAPR is restrained by selecting proper parameters and filters to make the underwater acoustic communication more efficient.
Conference Paper
Underwater acoustic (UWA) channels are characterized by low availability of bandwidth, large propagation delays and fast varying multipaths. The fast variation of multipaths, in particular, hampers the bandwidth efficiency of UWA channels, as a significant percentage of transmission resources should be allocated to pilots. The problem magnifies further in the case of multiple-input multiple-output (MIMO) channels as the number of pilots increases linearly with the number of transmitting transducers. This paper introduces the concept of massive MIMO (a technology that has recently been proposed as a candidate for 5G wireless communication systems) for UWA channels and shows that the choice of filter bank multicarrier (FBMC) modulation for transmission in a multicarrier system removes the need for pilots, hence achieves a high level of bandwidth efficiency.