the UComms`16 book of abstracts here.

Book of Abstracts of the
Third Underwater Communications
and Networking Conference - UComms’16
Aug.30 - Sep.1 2016, Lerici, Italy
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KEYNOTESPEECH...........................................................................................................................................1
UNDERWATERCOMMUNICATIONS:IERI,OGGIEDOMANI...........................................................................................1
APPLICATIONSANDREQUIREMENTS......................................................................................................2
ACOUSTICCOMMUNICATIONANDNAVIGATIONINTHENEWARCTIC-AMODELCASEFORENVIRONMENTAL
ADAPTATION........................................................................................................................................................................2
THESWIGACOUSTICSTANDARD.....................................................................................................................................2
HUMAN-ROBOTINTERACTIONUNDERWATER:COMMUNICATIONANDSAFETYREQUIREMENTS.....................3
UNDERWATERCOMMUNICATIONREQUIREMENTSINCOORDINATEDAUTONOMOUSMANIPULATION:THE
MARISPROJECT.................................................................................................................................................................3
EFFECTSOFMETALSTRUCTURESONMAGNETO-INDUCTIVECOUPLEDCOILS......................................................4
SUB-ICEGLIDERNAVIGATION&COMMUNICATION....................................................................................................4
PHYSICALLAYERINACOUSTICCOMMUNICATIONS...........................................................................6
DECISIONTREE-BASEDADAPTIVEMODULATIONFORUNDERWATERACOUSTICCOMMUNICATIONS..............6
ENERGY-EFFICIENTOFDMBANDWIDTHSELECTIONFORUNDERWATERACOUSTICCARRIERAGGREGATION
SYSTEMS...............................................................................................................................................................................6
ITERATIVESPARSECHANNELESTIMATIONFORACOUSTICOFDMSYSTEMS........................................................7
UNCODEDACOUSTICCOMMUNICATIONINSHALLOWWATERSWITHBURSTYIMPULSIVENOISE.....................7
BLINDEQUALIZATIONOFUNDERWATERACOUSTICCHANNELSUSINGIMPLICITHIGHER-ORDERSTATISTICS
................................................................................................................................................................................................8
MODEL-BASEDSIGNALDETECTIONINSNAPPINGSHRIMPNOISE...........................................................................8
ADAPTIVEPOWERALLOCATIONFORNONCOOPERATIVEOFDMSYSTEMSINUWAINTERFERENCE
CHANNELS............................................................................................................................................................................8
AUTONOMOUSPOWERCONTROLFORACOUSTICMODEMS.......................................................................................9
NETWORKING,LOCALISATIONANDSCHEDULING...........................................................................11
COLLABORATIVELOCALIZATIONOFVEHICLEFORMATIONSBASEDONRANGESANDBEARINGS...................11
ONTHEACCURACYOFPASSIVEMULTIPATH-AIDEDUNDERWATERRANGEESTIMATION...............................11
ADISTRIBUTEDIDASSIGNMENTANDTOPOLOGYDISCOVERYPROTOCOLFORUNDERWATERACOUSTIC
NETWORKS........................................................................................................................................................................12
UNSLOTTEDTRANSMISSIONSCHEDULESFORPRACTICALUNDERWATERACOUSTICMULTIHOPGRID
NETWORKSWITHLARGEPROPAGATIONDELAYS.....................................................................................................12
EXPERIMENTALDEMONSTRATIONOFSUPER-TDMA:AMACPROTOCOLEXPLOITINGLARGEPROPAGATION
DELAYSINUNDERWATERACOUSTICNETWORKS.....................................................................................................13
EFFICIENTLINKDISCOVERYFORUNDERWATERNETWORKS................................................................................13
NEARREAL-TIMEIMPROVEDUUVPOSITIONINGTHROUGHCHANNELESTIMATION..........................................14
SIMULATION,MODELSANDTESTBEDS...............................................................................................15
ANANALYSISOF1AND2-DARRAYSFORADAPTIVEMULTICHANNELEQUALIZERSINUNDERWATER
ACOUSTICCOMMUNICATIONS.........................................................................................................................................15
VERYHIGHFREQUENCYNOISESOURCESINTHELITTORALZONE........................................................................15
TETHEREDBALLOONSANDTVWHITESPACES:ASOLUTIONFORREAL-TIMEMARINEDATATRANSFERAT
REMOTEOCEANAREAS..................................................................................................................................................16
WIDE-BANDSHALLOWACOUSTICCHANNELSIMULATIONWITHREALISTICDOPPLERANDDELAYSPREADING
FOR3DEVOLVINGROUGHSURFACES...........................................................................................................................16
INTEROPERABILITYANDSTANDARDS................................................................................................17
ANALYSISOFJANUSANDUNDERWATERTELEPHONECAPABILITIESANDCO-EXISTENCE................................17
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EXPERIENCESWITHJANUSANDEFFORTSTOWARDSACOMMONHEAVY-DUTYUNDERWATER
COMMUNICATIONSTACK.................................................................................................................................................17
FOSTERINGTHEUSEOFJANUSINOPERATIONALLY-RELEVANTUNDERWATERAPPLICATIONS...................18
WATERMARK:AREALISTICBENCHMARKFORUNDERWATERACOUSTICMODEMS.............................................18
NON-ACOUSTICCOMMUNICATIONMODALITIES..............................................................................19
DEVELOPMENTANDVALIDATIONOFBLUERAY,ANOPTICALMODEMFORTHEMEDUSACLASSAUVS.......19
TEMPORALDISPERSIONINUNDERWATERLASERCOMMUNICATIONLINKS:CLOSINGTHELOOPBETWEEN
MODELANDEXPERIMENT...............................................................................................................................................19
EXPERIMENTALTESTBEDFORSEAWATERCHANNELCHARACTERIZATION..........................................................20
INVESTIGATIONONRADIOWAVEPROPAGATIONINSHALLOWSEAWATER:SIMULATIONSAND
MEASUREMENTS..............................................................................................................................................................20
OPTOCOMM:INTRODUCINGANEWOPTICALUNDERWATERWIRELESSCOMMUNICATIONMODEM..............21
DIPOLEANTENNAFORUNDERWATERRADIOCOMMUNICATIONS........................................................................22
NON-VISIBLELIGHTUNDERWATEROPTICALCOMMUNICATIONS...........................................................................22
ARCHITECTURESANDNOVELSTACKS.................................................................................................24
SEANETG3:HIGH-DATA-RATESOFTWARE-DEFINEDUNDERWATERACOUSTICNETWORKPLATFORM...24
THEDESERTUNDERWATERFRAMEWORKV2:IMPROVEDCAPABILITIESANDEXTENSIONTOOLS.............24
SECURITYINUNDERWATERCOMMUNICATIONS.............................................................................26
SECUREUNDERWATERACOUSTICNETWORKS:CURRENTANDFUTURERESEARCHDIRECTIONS..................26
ANALYTICALMETRICWEIGHTGENERATIONFORMULTI-DOMAINTRUSTINAUTONOMOUSUNDERWATER
MANETS...........................................................................................................................................................................26
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Keynotespeech
UnderwaterCommunications:ieri,oggiedomani
MilicaStojanovic,NortheasternUniversity,MA,USA
Inthispresentation,wetakeatourofunderwatercommunications,scrollingthorough
the past, present and future of key technologies, signal processing and networks. We
begin by briefly summarizing “the achievements of yesterday”—those that have
resulted in mature technology that is now routinely deployed in various scientific and
commercialsystems.Wefollowwithobservationsontoday’sresearchefforts,touching
upon the issues of channel estimation and equalization for single- and multi-carrier
communication systems, acoustics and optics, system integration and networking. At
present,thereisnodominantapplication(market)thatdrivestechnologydevelopment,
and the challenge to the scientific community is to continue to provide fundamental
building blocks that will push the application limits. The underlying issues are closely
intertwined with our major question: What is the future of underwater
communications? Or, if you prefer, what are the underwater communications of the
future? We invite the audience to participate in answering this question, so if you are
readingtheselines,thinkaboutanitemortwothatyouwouldputonthe“tomorrow”
list.
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ApplicationsandRequirements
(Chairs:RoaldOtnesandVladimirDjapic)
AcousticCommunicationandNavigationintheNewArctic-AModelCasefor
EnvironmentalAdaptation
HenrikSchmidt(MassachusettsInstituteofTechnology)
TobySchneider(GobySoft,LLC)
The particular sensitivity of the Arctic to climate change is well established, and the
significance to undersea operations can be dramatic. As part of the recent ICEX16 US
Navy Exercise in the Beaufort Sea, MIT deployed an autonomous underwater vehicle
with a towed hydrophone array below the ice cover for assessing the climate-induced
changes to the undersea ambient noise environment. The safe underwater operation
depended on navigation updates from the submarine tracking range being
communicatedtothevehicleforfusionwiththeonboardinertialnavigation.
However, the changes in the environment severely deteriorated the tracking
performance compared to previous deployments. The reason was clearly associated
with a previously observed neutrally buoyant layer of warm Pacific water persistently
spreadingthroughouttheBeaufortSea,whichseverelyalterstheacousticenvironment
with dramatic effects for both long and short range acoustic sensing, communication
and navigation. This paper describes the effects observed and discusses how robust
acoustic connectivity in this environment makes it paramount that the manned or
unmannedunderseaplatformsarecapableofadaptingtotheenvironmentforsensing,
communicationandnavigation.
TheSWIGacousticStandard
AndySmerdon(AquatecGroupLtd)
FranciscoBustamante(EvologicsGmbH)
MikeBaker(OTMConsulting)
This paper describes industry efforts to develop an underwater acoustic
communications standard for the offshore energy community. The Subsea Wireless
Group (SWiG), an international oil and gas industry network comprising operators,
installers, and technology companies, assessed a variety of potential use cases and
possibleroutestodevelopacommonstandard,culminatingintheselectionoftheJANUS
standard as a template. The paper explores typical use cases, the benefits of
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standardisationfortechnologydevelopersandusers,identificationofgapsintheJANUS
standard,andcurrentprogressindevelopingthestandard.
Human-RobotInteractionUnderwater:CommunicationandSafetyRequirements
NikolaMiskovic(UniversityofZagrebFacultyofElectricalEngineeringandComputing)
MuratEgi(DANEurope)
ĐulaNađ(UniversityofZagrebFacultyofElectricalEngineeringandComputing)
AntónioPascoal(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
LuisSebastiao(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
MarcoBibuli(CNR-ISSIA)
Safety is of particular interest when performing research related to human--robot
interactioninunpredictableandhazardousunderwaterenvironment.Specialattention
is devoted to safety requirements within FP7 project "CADDY - Cognitive Autonomous
Diving Buddy" in order to reduce hazards during experiments, since divers relying on
technologyforlifesupportareexposedtoadditionalriskoftraumaasaconsequenceof
impactwithamarinevehicle.
This paper focuses on the risk assessment of human--robot interaction in the
underwater environment within the scope of CADDY project. Each vehicle comprising
theCADDYfleetisanalyzedforanumberofrisks,andanoverallassessmentisprovided
showingtheappropriatenessofselectedvehiclesfortheapplication.Also,theacoustic
communication scheme used in the project is described, as a means of efficient and
robustnavigationdataexchangeforthepurposeofminimizingtheriskoftraumadueto
unwantedcontactbetweenthevehiclesandthediver.
UnderwaterCommunicationRequirementsinCoordinatedAutonomousManipulation:the
MARISProject
DavideFenucci(DepartmentofInformationEngineering,UniversityofPisa)
AndreaCaiti(DepartmentofInformationEngineering,UniversityofPisa)
EnricoSimetti(DIBRIS,UniversityofGenova)
GiuseppeCasalino(DIBRIS,UniversityofGenova)
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This paper addresses the communication requirements needed within the MARIS
project, which involves several Italian institutions. The goal of the MARIS project is to
developtechnologiesforautonomousunderwaterinterventions,inparticulartoenable
twofloatingmanipulatorsinexecutingjointgrasp-ingandtransportationactivities.In
this context, communication issues are mainly related to the information exchange
neededbythecooperationalgorithmsduringallthephasesofthemission,inparticular
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in the coordinated transportation. Simulation results show the expected performances
ofthecooperativealgorithmasthecommunicationratechanges.Basedontheseresults,
a strategy to meet the requirements imposed by the cooperation and to achieve the
missionobjectivewiththeavailabledevicesispresented.
EffectsofMetalStructuresonMagneto-InductiveCoupledCoils
NiazAhmed(MissouriUniversityofScienceandTechnology)
YahongZheng(MissouriUniversityofScienceandTechnology)
DavidPommerenke(MissouriUniversityofScienceandTechnology)
This paper analysizes the effects of metal structures in near-field Magneto-Inductive
(MI)communicationsystems,wherethetransmitterand/orreceivercoilsmaybeclose
to large metal structures that has high magnetic permeability and conductivity.
EMCoStudiosimulationsshowthatthepresenceofmetalstructurehelptoincreasethe
coupling magnitude if placed nearby the transmit and receive coils, but reduces
significantifplacedbetweenthetransmitandreceivecoils.
Sub-IceGliderNavigation&Communication
(“Off-the-record”paper)
AndreyMorozov(TeledyneMarine)
DaleGreen(TeledyneMarine)
ClaytonJones(TeledyneMarine)
Navigation and telemetry for AUVs operating in the Arctic currently rely on GPS and
satellitecommunicationsthatarepoorlysuitedforpolarareascoveredbyicerestricting
accesstotheseasurface.Althoughthedatarateoflongrangeacousticcommunications
ismuchlessthansatellitecommunications,andtheprecisionofacousticalnavigationis
less than GPS, underwater acoustic systems are the only way to provide geo-location
and telemetry in ice-covered regions. The Teledyne broadband sound sources with
precision clocks can provide underwater navigation in the Arctic, with frequency and
signalsselectedfortherangesofinterest,whichspantenstothousandsofkilometers.
Approachesconsideredhereforlow-frequencysourcesincludebroadbandandtunable
resonant transducers in a frequency range 5-1000 Hz: dual-resonant sources; tunable
organ pipes and gas-filled seismic sources. While light and small dual-resonant
compositepipesoundsourcesinafrequencyrange500-1000Hzcanprovidelow-data
rate communications with gliders at the distance 100-300 km, swept frequency sound
sources in 150-500 Hz range can provide navigation signals for thousand kilometers;
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gas filled seismic sources in frequency range 5-150 Hz are useful for a global ocean
navigationtocovertensthousandsofkilometers.
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PhysicalLayerInAcousticCommunications
(Chairs:JamesPreisig,GrantDeaneandCostasPelekanakis)
DecisionTree-BasedAdaptiveModulationforUnderwaterAcousticCommunications
CostasPelekanakis(CMRE)
LucaCazzanti(CMRE)
GiovanniZappa(CMRE)
JoãoAlves(CMRE)
Underwateracousticchannelsarecharacterisedbynon-stationaryfadingstatisticsand
consequently,amodulationschemeoptimallydesignedforaspecificfadingmodelwill
underperformwhenthechannelstatisticschange.Thisissuecanbealleviatedbyusing
adaptive modulation, i.e., the matching of the modulation scheme to the conditions of
the acoustic link. However, selecting signals from a broad range of bit rates is tedious
because one needs to know the relationship between the bit error rate (BER) and all
relevant channel characteristics (e.g., multipath spread, Doppler spread and signal-tonoise ratio). In this work, this relationship is extracted from large amounts of
transmissions of a phase-shift keying (PSK) single-carrier modem. In particular, a
decision tree is trained to associate channels with modulation schemes under a target
BER.Theeffectivenessoftheproposedtreemethodisdemonstratedbypost-processing
datafromtwoexperimentallinksoffthecoastofFaialIsland,Azores,Portugal.
Energy-efficientOFDMBandwidthSelectionforUnderwaterAcousticCarrierAggregation
Systems
XueyuanZhao(RutgersUniversity)
DarioPompili(RutgersUniversity)
JoãoAlves(CMRE)
The energy efficiency of underwater acoustic carrier aggregation in Orthogonal
Frequency Division Multiplexing (OFDM) systems is studied and an energy efficient
aggregationbandwidthselectionmethodisproposed.Viasimulationsitisfoundthat(i)
the aggregation bandwidth has an optimal value maximizing the energy efficiency, (ii)
this optimal aggregation bandwidth decreases with increasing distance, and (iii) the
energyefficiencyatthisoptimalbandwidthdropssignificantlyfordistancesabove5km.
Based on these results, an energy-efficient aggregation bandwidth selection method is
proposed for an underwater system composed of a surface buoy and Autonomous
Underwater Vehicles (AUVs). The proposed method is expected to optimize the
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transmission energy utilization by feeding back the optimal bandwidth value from the
receivertothetransmitterfordifferentdistancesettings.Tovalidatetheresultsunder
varying acoustic channel conditions, field experiments on the LOON testbed hosted at
theNATOSTOCentreforMaritimeResearchandExperimentation(CMRE)arecurrently
ongoing.
IterativeSparseChannelEstimationforAcousticOFDMSystems
SayedamirhosseinTadayon(NortheasternUniversity)
MilicaStojanovic(NortheasternUniversity)
We propose a method for channel estimation in orthogonal frequency division
multiplexing (OFDM) systems with an array of receiving elements. In contrast to
traditional methods, which target the equivalent sample-spaced channel taps, this
method targets the physical propagation paths whose delays are not restricted to the
sample-spaced grid. The path delays are estimated jointly with the path gains and the
angles of arrival, exploiting coherence between the array elements. Numerical results
illustratesuperiorperformanceascomparedtotap-basedchannelestimation,aswellas
additionalgainavailablefromspatialcorrelationacrossthearrayelements.
UncodedAcousticCommunicationinShallowWaterswithBurstyImpulsiveNoise
AhmedMahmood(NationalUniversityofSingapore)
MandarChitre(NationalUniversityofSingapore)
The shallow underwater acoustic channel offers a challenging environment. Besides
long delay spreads caused by multiple surface-bottom reflections, the channel is time
variant as well. In tropical waters, the problem is compounded further by impulsive
noise created by snapping shrimp. Conventionally, the noise process is modeled by
whiteimpulsivenoise.However,inreality,snappingshrimpnoisedepictsmemoryand
isthusburstyaswell.Weinvestigatetheperformanceofahigh-rateuncodedacoustic
communication system operating in tropical shallow waters. The stationary α-subGaussiannoisewithmemoryorderm(αSGN(m))modelisemployedasitcharacterizes
both the temporal and amplitude statistics of snapping shrimp noise. We show that
there is a stark deviation from the expected performance of the white maximumlikelihood (ML) detector when the ambient noise is αSGN(m) (m > 0). Moreover, we
derive the ML detector for the shallow water acoustic channel with additive αSGN(m)
andcompareitsperformancetothatofitswhitecounterpart.
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BlindEqualizationofUnderwaterAcousticChannelsusingImplicitHigher-OrderStatistics
KoenBlom(TNO)
HenryDol(TNO)
AndréKokkeler(UniversityofTwente)
GerardSmit(UniversityofTwente)
In order to reduce the length of transmission time slots and energy consumption of
underwater modems, this work focuses on equalization without the need for training
sequences. This type of equalization is known as blind equalization. A blind equalizer
cascade based on higher-order statistics is presented and evaluated using sea-trial
replaydata.Thesubcomponentsofthecascadeuseincreasinglystringentnonlinearcost
criteriarootedintheconstantmodulusalgorithm.Initialresultsrevealthatthecascade
can cope with the time variance of a realistic channel and largely mitigates its
convolutionalerror.
Model-BasedSignalDetectioninSnappingShrimpNoise
AhmedMahmood(NationalUniversityofSingapore)
HariVishnu(NationalUniversityofSingapore)
MandarChitre(NationalUniversityofSingapore)
Inanumberofscenarios,detectingthepresenceorabsenceofaknownsignalmaybeof
practical interest. One such example lies in a communication setting, where packet
detectionisavitalfirststeptodecodetransmitteddata.Thedetectionproblemcanbe
formulatedasabinaryhypothesistestwithintheNeyman-Pearson(NP)framework.Our
scenarioofinterestiswarmshallowwaters,wheretheseafloorisinhabitedbycolonies
ofsnappingshrimp.Theambientnoiseinsuchacaseisimpulsiveandexhibitsmemory.
We investigate the performance of optimal detectors corresponding to four additive
noise models in snapping shrimp noise. In the literature, proposed detectors typically
takeonlytheamplitudestatisticsofthenoiseprocessintoaccount.Byalsoconsidering
thememory,weshowthatthereissubstantialimprovementindetectionperformance.
The detector in the latter case is based on the recently introduced stationary α-subGaussiannoisewithmemoryorderm(αSGN(m))model,whicheffectivelycharacterizes
thetemporalamplitudestatisticsofthesnappingshrimpnoiseprocess.
AdaptivePowerAllocationforNoncooperativeOFDMSystemsinUWAInterference
Channels
AntonyPottier(TelecomBretagne)
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Francois-XavierSocheleau(TelecomBretagne)
ChristopheLaot(TelecomBretagne)
Noncooperative underwater acoustic (UWA) communication systems are prone to
interfere with each other since the limited resource offered by the channel is not
regulated by any standard. Mutual inteferences can significantly degrade the
performancesofsuchsystemsanditisnecessarytofindpoliciesallowingUWAdevices
to access the same physical resource. In this paper, we consider noncooperative UWA
OFDMsystemscompetingtoaccessthesameportionofthespectrum.Weshowthatan
efficient decentralized power allocation strategy can be achieved when all the
communication links apply a waterfilling policy only based on little knowledge about
theirenvironment.NumericalsimulationsperformedwithrealUWAchannelssounded
at-seademonstratetherelevanceofourapproach.
AutonomousPowerControlForAcousticModems
(“Off-the-record”paper)
DaleGreen(TeledyneBenthos)
AdaptivePowerControlisacapabilityinwhichtheacousticmodemsmakeautonomous
decisions to adjust their transmit power levels to provide reliable acoustic
communicationsandrangingmeasurementsatthelowestpossiblesignaltonoiseratio
(SNR).Thealgorithmusesasinglehandshaketoestablishtheminimumtransmitpower
level for communications between two modems, then monitors background noise to
enablefuturecommunicationswithouttheneedforfurtherhandshaking.
The Adaptive Power Control algorithm requires the modem to both characterize the
backgroundnoiseandtoaccuratelymeasureSNR.Analgorithmtomeasureandreport
backgroundnoisewasvalidatedandaddedtothemodem.TheTeledyneBenthos(TB)
modem already had an ability to measure SNR, but this limited version was only valid
for very modest multipath conditions. We developed an extension to the existing
algorithmwhichproperlyincorporatestheenergycontainedinallsignificantpaths.We
also developed a separate algorithm appropriate for other signalling schemes with a
different acquisition structure, and demonstrated the close performance between the
twomethods.Severalat-seaexperimentswereconducted,withextensivedatacollected
tosupportthevalidationofouralgorithms.Weconductedanextensiveevaluationofthe
SNR requirements for good receiver performance using simulation in additive white
Gaussiannoise(AWGN).Theevaluationwasmadeforalldataratesavailableusingour
standard multi-channel M-ary frequency shift keyed (MFSK) signalling and for
frequency hopping (FH), and other methods as well. The analysis used a completely
knownsignal(equivalenttoasingledirect-pathenvironment),soeffectssuchasrange
rate and time-varying channels were not included. However, all of these methods use
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non-coherentdemodulationwhichtendstoaddtheenergyinallmultipaths,soournew
SNR-measurement algorithms, which inform the modem of the total available energy,
are appropriate. Until at0sea experience suggests otherwise, we add 2 dB to the
required(AWGN)SNRtoaccountforreal-world,at-seaconditions.
Wehavedevelopedthefollowing:
1.
Theabilitytomeasurebackgroundnoisepowerinanappropriateway
2.
TheabilitytomeasureSNRinawaythatincorporatesallsignificant(multipath)
energy
3.
TabulatedtherequiredSNRforallavailablemodulationsschemes.
Our present efforts identified the need to incorporate range as a metric for power
control.Webelievethisisanimportantareaforfuturestudy,becauseitisapplication
and scenario dependent. However, it is not addressed here. Aside from range
implications,wehaveidentified,developed,andimplementedinthemodem,acomplete
adaptivepowercontrolsystemappropriateforstaticgeometries.
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Networking,LocalisationandScheduling
(Chairs:LeeFreitag,ChiaraPetrioliandAndreaMunafò)
CollaborativeLocalizationofVehicleFormationsBasedonRangesandBearings
BeatrizFerreira(ISR-InstitutoSuperiorTécnico,UniversidadedeLisboa)
JoãoGomes(ISR-InstitutoSuperiorTécnico,UniversidadedeLisboa)
CláudiaSoares(ISR-InstitutoSuperiorTécnico,UniversidadedeLisboa)
JoãoCosteira(ISR-InstitutoSuperiorTécnico,UniversidadedeLisboa)
We examine the problem of jointly determining the positions of multiple underwater
vehicles based on a set of pairwise range and bearing measurements taken over time.
This extends prior work on the so-called (static) collaborative localization paradigm
whereahybridapproachwasproposedforseamlessinstantaneousfusion(i.e.,notime
dependence) of range and bearing measurements. To incorporate time we add to the
original convexified least-squares cost function a regularizing term that penalizes
deviations between predicted and computed vehicle positions at a given instant. The
methodoperatesprogressivelyovertime,withpastestimatesusedforpredictionatthe
current instant assuming a very simple quasi-linear motion model. The method is
amenable to parallelization, with simple gradient-like updates. Numerical results
demonstratepromisingaccuracygains(reductionontheorderof10%intermsofrootmean-square positioning error) in simulations inspired by an underwater geoacoustic
surveyingapplication.
OntheAccuracyofPassiveMultipath-AidedUnderwaterRangeEstimation
ElizavetaDubrovinskaya(IMDEANetworksInstitute,Madrid;UniversidadCarlosIII,Madrid)
Ivor Nissen (Research Department for Underwater Acoustics and Marine Geophysics (FWG),
WTD71Kiel)
PaoloCasari(IMDEANetworksInstitute,Madrid)
We consider range estimation algorithm based on the time differences between
different arrivals of the signal transmitted by an anchor node of known location. We
assumethatonlytheanchornodecantransmitinformation.Weconsiderthegeometry
oftheprobleminthesimplifiedcaseofaconstantsoundspeedprofile(SSP),andargue
thatthemorerealisticcaseofanon-constantSSPcanbestilltackledasiftheSSPwere
constant, provided that an effective sound speed value is computed based on the
geometryofthesignalpropagation.
Wethenevaluatetheaccuracyofthelatterapproachinthepresenceoferrorsaffecting
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different quantities required for the range estimation process, including the TDoA
values,thebottomdepth,andthedepthofthenodetowhichtherangeiscomputed.Our
resultsshowthatourapproachoffersimprovedaccuracywithrespecttoabaselineLSE
estimator.
ADistributedIDAssignmentandTopologyDiscoveryProtocolforUnderwaterAcoustic
Networks
RobertoPetroccia(CMRE)
This paper presents a new protocol to self assign node IDs in an Underwater Acoustic
Network(UAN).Theproposedsolution,termedDIVEforDistributedIdassignmentand
topologydiscoVEry,isfullydistributedandself-adaptive.WhileassigningthenodeIDs,
additionalinformationissharedtodiscovertheothernodesinthenetwork,thetypeof
thesenodes(staticormobile),andthenumberofhopstoreachthem.TheDIVEprotocol
exploits link quality information to increase its reliability and robustness against
message losses. The protocol performance has been evaluated under a variety of
networking scenarios including node mobility, and node addition and removal.The
resultsshowthatDIVEisanefficientandreliablesolutionfornodeIDassignmentand
network discovery, which scales with the network size in the presence of a unreliable
channel.
UnslottedTransmissionSchedulesforPracticalUnderwaterAcousticMultihopGrid
NetworkswithLargePropagationDelays
PrasadAnjangi(NationalUniversityofSingapore)
MandarChitre(NationalUniversityofSingapore)
In a recent work, a regular grid-based network topology with multihop relaying was
investigated.Atransmissionstrategywhichmaximizesthethroughputwhileexploiting
the large propagation delay was presented, and the upper bound on throughput
established. However, deployments of communication nodes in the ocean inevitably
result in slight positional deviations from the expected locations of the nodes, a
departurefromtheperfectlyalignedregulargridnetworksassumed.Theirregularityin
the grid network due to deployment errors degrades the network throughput
significantly.Weconsiderthispracticalproblemandproposeanalgorithmtocompute
unslotted transmission schedules. We formulate the scheduling problem as a MixedInteger Linear Problem (MILP) and compute throughput-maximizing schedules. We
demonstrate the throughput gain compared to the existing state of the art techniques
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and verify the solution in the simulator for various random instances of the grid
networkdeployment.
ExperimentalDemonstrationofSuper-TDMA:AMACProtocolExploitingLarge
PropagationDelaysinUnderwaterAcousticNetworks
PrasadAnjangi(NationalUniversityofSingapore)
MandarChitre(NationalUniversityofSingapore)
The potential of exploiting large propagation delays in underwater acoustic (UWA)
networks to maximize the network throughput is established in the recent past.
Transmission scheduling strategies have been proposed to take advantage of large
propagation delay. Super-TDMA is one among such Medium Access Control (MAC)
strategies proposed. It is a form of Time Division Multiple Access (TDMA) protocol in
whichmultipletransmissionsareallowedinthesametimeslotandhenceconcurrently
propagateinthemedium.WepresenttheimplementationchallengesofSuper-TDMAon
underwateracousticmodemsandtheexperimentalresultsdemonstratinginterference
alignment, the crossing of simultaneously transmitted packets in water, and the time
synchronizationamongthedeployednodesinthenetwork.
EfficientLinkDiscoveryforUnderwaterNetworks
RoeeDiamant(UniversityofHaifa)
RobertoFrancescon(UniversityofPadova)
MicheleZorzi(UniversityofPadova)
We describe an efficient method to discover the topology of underwater acoustic
networks (UWANs). By knowing the network topology, nodes can determine
destinations and routing possibilities for their packets, and schedule transmissions
accordingly.Todetectthenetworktopology,aninitialphaseisemployed.Ouralgorithm
aims to reduce the time overhead of this initial phase while accurately discovering
acoustic links. To that end, our algorithm allows simultaneous transmissions from
different nodes while controlling the number of possible collisions in an optimized
fashion. Experimental results from the 14~days ALOMEx'15 sea expedition show that
ouralgorithmisabletoaccuratelydetectthenetworktopologyinamuchshortertime
comparedtobenchmarkmethods.
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Nearreal-timeimprovedUUVpositioningthroughchannelestimation
RenatoVio(NavalPostgraduateSchool)
RobertoCristi(NavalPostgraduateSchool)
KevinSmith(NavalPostgraduateSchool)
Underwaternavigationsystemsaresusceptibletoawidevarietyoferrors.Atechnique
to accurately update the position of an autonomous system, while underwater, is
extremelydesirable.Theprimaryobjectiveofthisworkistoenhancethenavigational
and positioning accuracy of Unmanned Underwater Vehicles (UUVs) by networking a
number of Unmanned Surface Vehicles (USVs) utilizing underwater acoustic modems
andacoustictraveltimecalculations.Thedevelopmentofatrackingalgorithmbasedon
the Extended Kalman Filter (EKF) and the use of underwater acoustic ray tracing
algorithms to estimate accurate ranges between USVs and UUVs are demonstrated. A
combination of the EKF with a Smoothing Algorithm was developed and extensively
testedwithsyntheticdata.Tovalidatetheconcepts,thetrackingalgorithmwasapplied
todatacollectedduringseateststhattookplaceinMontereyBayinAugust,2015.
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Simulation,ModelsandTestBeds
(Chairs:SérgioJesusandPaulvanWalree)
Ananalysisof1and2-Darraysforadaptivemultichannelequalizersinunderwater
acousticcommunications
(“Off-the-record”paper)
JamesPreisig(JPAnalytics,LLC)
GrantDeane(ScrippsInstitutionofOceanography,UCSD)
Hydrophonearraysformultichannelequalizersareusedtospatiallyfilterthereceived
signalandmitigatethenegativeimpactofmultipath-inducedIntersymbolInterference
(ISI)andambientnoise.Whilethemultipathstructureintheoceanisprimarilyvertical,
the ambient noise structure is both horizontal and vertical. Thus, as SNR is decreased
theoptimalconfigurationofahydrohonearrayisexpectedtotransitionfromthatofa
vertical line array to a 2-D geometry with both horizontal and vertical aperture. This
paper presents an analysis of the impact of the spatial structure of the acoustic
multipath and ambient noise on equalizer performance and a methodology for
quantifying the impact to be used in optimizing receiver array geometry. The
accompanying talk will present the results of the trade-study of array geometry as a
functionofSNRbaseduponthemethodologydevelopedhere.
VeryHighFrequencyNoiseSourcesintheLittoralZone
GrantDeane(ScrippsInstitutionofOceanography,UCSD)
JamesPreisig(WoodsHoleOceanographicInstitution)
Recent interest in very high frequency (VHF, here defined as > 300kHz) underwater
acousticcommunicationshasmotivedastudyofVHFnoisesourcesinthelittoralzone.
The Littoral is a special environment for underwater ambient noise. Near shore
bathymetry induces wave breaking and wave-sediment interactions, both of which
generateunderwaternoise,andavarietyofmarineorganismscanradiatenoiseacrossa
broad acoustic spectrum. Two potential VHF noise sources, breaking waves and
snappingshrimp,areconsideredhere.Measurementsofthenoiseradiatedbybreaking
laboratorywavesarepresented,whichshowthatwavenoisecanextendtoatleast400
kHz.Modelcalculationsofthepulseofsoundradiatedbyacollapsingcavitationbubble
generated by a snapping shrimp jet show the potential for significant spectral
componentsupto1MHz.Theimplicationsforthesenoisesourcesonthetemporaland
spatialdistributionoftheVHFnoisefieldarediscussed.
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TetheredBalloonsandTVWhiteSpaces:ASolutionforReal-timeMarineDataTransferat
RemoteOceanAreas
FilipeTeixeira(INESCTEC)
TiagoOliveira(INESCTEC)
MárioLopes(INESCTEC)
JoséRuela(INESCTEC)
RuiCampos(INESCTEC)
ManuelRicardo(INESCTEC)
Autonomous Underwater Vehicles and Remotely Operated Vehicles are useful in
industries such as offshore Oil and Gas, deep sea mining, and aquaculture, where
inspection missions are frequent. While underwater communications are mainly done
using acoustic links, retrieving data from these devices to shore is still an open issue,
especially when we consider the high cost of satellite communications. In this paper,
using ns-3 simulations, we evaluate the ability of the communications solution being
developedintheBLUECOM+projecttoenablereal-timemarinedatatransferatremote
oceanareas.Throughtheusageoftetheredballoons,TVwhitespacesfrequencies,and
multi-hop communications, the BLUECOM+ solution enables cost-effective, broadband
connectivity to the Internet at remote ocean areas, using standard access technologies
such as GPRS/UMTS/LTE and Wi-Fi. Simulation results show an expected range
exceeding100kmfromshoreusingonlytwonodesatsea,withbitratesover1Mbit/s.
Wide-bandshallowacousticchannelsimulationwithrealisticDoppleranddelayspreading
for3Devolvingroughsurfaces
MichaelCaley(CurtinUniversityofTechnology)
AlecDuncan(CurtinUniversityofTechnology)
A phase-coherent shallow underwater multipath channel simulation is described that
combines the eigenpath amplitude/delay responses from a ray-tracing model for the
flat-surfacechannelgeometry,withthetime-varyingmicro-pathresponsesderivedfrom
signal interactions with successive 3D realisations of the rough surface. The timevaryingroughsurfaceresponseiscalculatedfromadiscreteseriesoftime-circular3D
rough surface realisations, allowing the resulting time-circular channel impulse
response to be used with test signals of arbitrary length. The simulated channel is
synthetically probed to present comparisons of Doppler and delay spreading
characteristicsofmeasuredandsimulatedreplicachannels.
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InteroperabilityandStandards
(Chairs:DaleGreenandJoãoAlves)
AnalysisofJANUSandunderwatertelephonecapabilitiesandco-existence
JoãoAlves(CMRE)
JustusCh.Fricke(BundeswehrTechnicalCentreforShipsandNavalWeapons,NavalTechnology
andResearch(WTD71))
This document aims at offering a concise look into the co-existence of Underwater
TelephoneandJANUSdigitalcommunicationmethods.Thistopicisofparticularinterest
as both methods (one a well-established STANAG and the latter in the process to
becomeaSTANAG)havepartiallyoverlappingfrequencybands.Thetwotechniquesare
brieflydescribedandthespecificinterferencemitigationstrategiesbuilt-ininJANUSare
presented.Thedocumentthenfocusesonaseriesofexperimentsconductedduringthe
REP14-Atlanticseatrials.Theseexperimentshadtwomainobjectives:1)Measuringthe
impact of an interfering JANUS signal on the intelligibility of voice messages and 2)
assessingthecapabilitiesofbothtechniquesundersimilarconditionsandvalidationof
theJANUSMediumAccessControlscheme.Experimentalsetup,analysisandresultsare
presentedforthedifferentactivities.
ExperienceswithJANUSandeffortstowardsacommonheavy-dutyunderwater
communicationstack
HenryDol(TNO)
KoenBlom(TNO)
ErnestVanDerSpek(DMO)
AnewEuropeanDefenceAgency(EDA)projectiscurrentlybeingsetup,calledSALSA,
in which five European nations are working towards a common underwater
communication stack for heavy-duty purposes, i.e., a rugged protocol stack that can
serveasthefuturecommunicationbackbonefornavaloperationsinvolvingautonomous
underwater vehicles (AUV) and bottom nodes. The emerging NATO standard JANUS is
envisioned as first-contact protocol in the SALSA stack, enabling ad-hoc extensions of
the underwater network such as in-mission upscaling of the number of AUVs in joint
operations. In this context, the JANUS modulation has been tested at sea for several
communication ranges and Doppler shifts, comparing its performance with the
candidatephysical-layerprotocoloftheSALSAstack.
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FosteringtheUseofJANUSinOperationally-RelevantUnderwaterApplications
RobertoPetroccia(CMRE)
JoãoAlves(CMRE)
GiovanniZappa(CMRE)
ThispaperpresentstheuseofJANUSinoperationally-relevantunderwaterapplications.
JANUS is an open, simple and robust digital coding technology currently in process to
become a NATO standard. Two underwater scenarios have been considered: 1)
BroadcastofunderwaterAISandsituationalawarenessmessages;2)Firstcontactand
languageswitching.
The JANUS physical coding scheme has been used by the underwater nodes as the
common "language" to share data and to negotiate the switching into a different
language, if needed. Field experiments have been conducted to test and validate the
proposedapproach.Differentandheterogeneousconfigurationshavebeenconsidered.
Inthispaperwepresentthecollectedresultsandlessonslearntwhichareapromising
startingpointforfosteringtheresearchinthisarea.
Watermark:Arealisticbenchmarkforunderwateracousticmodems
PaulvanWalree(NorwegianDefenceResearchEstablishment(FFI))
RoaldOtnes(NorwegianDefenceResearchEstablishment(FFI))
TrondJenserud(NorwegianDefenceResearchEstablishment(FFI))
WATERMARK is a benchmark for testing, development, and comparison of physicallayer schemes for underwater acoustic communications. Its core is a replay channel
simulator driven by at-sea measurements of the time-varying impulse response.
WATERMARK is programmed in MATLAB and is initially provided with two (singlereceiver) test channels with a run time of 30 minutes each. These channels were
measured in Norwegian waters in the frequency band from 10 to 18 kHz. The
benchmarkcanbeextendedwithchannelsfromdifferentenvironmentsandfrequency
bands,dependingonthewillingnessofthirdpartiestoperformandmakeavailablesuch
measurements.
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Non-AcousticCommunicationModalities
(Chairs:BrandonCochenourandFraserDalgleish)
DevelopmentandValidationofBlueRay,anOpticalModemfortheMedusaclassAUVs
PedroGois(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
NichinSreekantaswamy(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
NandeeshBasavaraju(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
ManuelRufino(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
LuisSebastiao(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
JoaoBotelho(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
JoaoGomes(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
AntonioPascoal(ISR-InstitutoSuperiorTecnico,UniversidadedeLisboa)
Wirelessopticalcommunicationsareemergingasaviablesolutionforhigh-speeddata
transmission over short ranges in the ocean, complementing mainstream acoustic
communicationsystemsthatoperateovermuchlongerranges,butatlowerdatarates.
The current drive to develop cooperative autonomous vehicular systems to carry out
surveyingandothercomplexmissionsintheoceancriticallydependsontheexistenceof
such communication links to share sensory and coordination information. This paper
presents a compact, low power consumption, cost-efficient, and lightweight optical
modem designed for fast data transmission between MEDUSA underwater vehicles at
ranges on the order of 10m. The transmitter uses LEDs for ON-OFF keying, while the
receiver front-end adopts a transimpedance architecture with a photodiode detector.
This simplistic transmission and reception technique reduces the overall design and
hardware complexities compared to, e.g., laser diodes and photomultiplier tubes. The
LEDs are arranged in a circular array, with a photodiode at the centre to enable halfduplex operation. These modems are designed to achieve data rates of 20 - 200 kb/s
overshort-range,line-of-sight,configurations.Atransparentcasingiscustomisedtofit
the MEDUSA vehicles, with proper alignment for inter-vehicle communication when
theymoveinformation.
Temporaldispersioninunderwaterlasercommunicationlinks:Closingtheloopbetween
modelandexperiment
BrandonCochenour(NavalAirWarfareCenter)
AlanLaux(NavalAirWarfareCenter)
LindaMullen(NavalAirWarfareCenter)
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development of numerous theoretical models to predict both signal attenuation and
bandwidth(pulsespreading)forunderwateropticallinks.Few,ifany,ofthesemodels
have been experimentally validated, owing mostly to the difficulty in experimentally
measuring temporal dispersion in these challenging environments. In this work, we
begintoclosetheloopbetweentheoryandexperiment,byvalidatinganumericalMonte
Carlomodelagainstexperimentaldata.Channelattenuationandfrequencyresponseis
measuredoutto1GHzover20attenuationlengthsinaline-of-sightconfiguration.
Experimentaltestbedforseawaterchannelcharacterization
PabloMena(UniversidaddeLasPalmasdeGranCanaria/IDeTIC)
PabloDorta(UniversidaddeLasPalmasdeGranCanaria/IDeTIC)
GaraQuintana(UniversidaddeLasPalmasdeGranCanaria/IDeTIC)
IvanPerez-Alvarez(UniversidaddeLasPalmasdeGranCanaria/IDeTIC)
EugenioJimenezYguacel(UniversidaddeLasPalmasdeGranCanaria/IDeTIC)
SantiagoZazo(UniversidadPolitecnicadeMadrid/ETSITelecomunicacion)
MarinaPerez(UniversidadPolitecnicadeMadrid/ETSITelecomunicacion)
LauraCardona(OceanicPlatformoftheCanaryIslands(PLOCAN))
J.JoaquinHernandez(OceanicPlatformoftheCanaryIslands(PLOCAN))
Shallow seawaters are problematic for acoustic and optical communications. Sensor
networks based on electromagnetic (EM) communications are evaluated in this
environment. In order to characterize the underwater channel, several measurement
systemshavebeendesigned,builtandtestedintheseaobtainingveryreliableresults.
Experimentscarriedoutwithdipolesandloopantennasshowedseriousdisagreement
withthestateoftheart,especiallywhendipoleantennasareused.Dipolesperformance
waspoorwhilemagneticloopsshowedmuchlowerattenuation.Ameasurementsystem
is described in detail and real attenuation of the underwater channel is obtained for
severaldistancesandantennas.Finally,measuredandsimulatedresultsarecompared
andrevealgoodagreement.
InvestigationonRadioWavePropagationinShallowSeawater:Simulationsand
Measurements
EugenioJimenezYguacel(UniversityofLasPalmasdeGranCanaria/IDeTIC)
GaraQuintana(UniversityofLasPalmasdeGranCanaria/IDeTIC)
PabloMena(UniversityofLasPalmasdeGranCanaria/IDeTIC)
PabloDorta(UniversityofLasPalmasdeGranCanaria/IDeTIC)
IvanPerez-Alvarez(UniversityofLasPalmasdeGranCanaria/IDeTIC)
SantiagoZazo(UniversidadPolitecnicadeMadrid/ETSITelecomunicacion)
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MarinaPerez(UniversidadPolitecnicadeMadrid/ETSITelecomunicacion)
EduardoQuevedo(OceanicPlatformoftheCanaryIslands(PLOCAN))
The authors present full wave simulations and experimental results of propagation of
electromagnetic waves in shallow seawaters. Transmitter and reciever antennas are
tenturnsloopsplacedontheseabed.Somepropagationframeworksarepresentedand
simulated.Finally,simulationresultsarecomparedwithexperimentalones.
OptoCOMM:introducinganewopticalunderwaterwirelesscommunicationmodem
AndreaCaiti(DepartmentofInformationEngineering,UniversityofPisa)
ErnestoCiaramella(ScuolaSuperioreSant’Anna,InstitutoTeCIP)
Giuseppe Conte (Dipartimento di Ingegneria dell’Informazione, Universitá Politecnica delle
Marche)
GiulioCossu(ScuolaSuperioreSant’Anna,InstitutoTeCIP)
Daniele Costa (Dipartimento di Ingegneria dell’Informazione, Universitá Politecnica delle
Marche)
SimoneGrechi(DepartmentofInformationEngineering,UniversityofPisa)
RogerNuti(DepartmentofInformationEngineering,UniversityofPisa)
David Scaradozzi (Dipartimento di Ingegneria dell’Informazione, Universitá Politecnica delle
Marche)
AlessandroSturniolo(ScuolaSuperioreSant’Anna,InstitutoTeCIP)
OptoCOMM aims at demonstrating the potential, at physical level, of a communication
facility for the SUNRISE platform constituted by an Optical Underwater Wireless
Communication(OUWC)modulewithtargetperformanceof10Mb/stransmissionrate
at 10 meters range in shallow medium/high turbidity harbour waters. The module,
whichisbasedonblueLightEmittingDiode(LED)unitsandcommonphotodiodes,isan
evolutionoftheproof-of-principleprototypealreadyproveninlaboratory(pool).Itwill
constitute an additional node integrated in the Littoral Ocean Observatory Network
(LOON) test-bed of the SUNRISE infrastructures, providing a high speed and short-
range communication node, which will complete the capability of acoustic modems
already present in the test-bed. Three modules (nodes) will be developed and
experimentallydemonstrated:onefordirectintegrationwiththeLOONinfrastructures,
one,batterypowered,tobepotentiallyinstalledonbuoys,RemotelyOperatedVehicles
(ROVs), etc., and one to be installed on the eFolaga Autonomous Underwater Vehicle
(AUV)oftheproponents.Thepaperdescribesindetailthedevelopmentofthemodems
as well as the first lab experiments, where the core technology has been successfully
tested.
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DipoleAntennaforUnderwaterRadioCommunications
SofiaInácio(INESCTEC)
MárioPereira(INESCTEC)
HugoSantos(INESCTEC)
LuísPessoa(INESCTEC)
FilipeTeixeira(INESCTEC)
MárioLopes(INESCTEC)
OluyomiAboderin(INESCTEC)
HenriqueSalgado(INESCTEC)
The radiation characteristics of a dipole antenna when immersed in both fresh and
seawater are assessed through simulation and experimental work. Simulations show
that the antenna's bandwidth and radiation pattern change with the properties of the
medium where it is placed, namely the conductivity of the medium. Two dipoles
antennas with current baluns were built and tested experimentally in freshwater. The
tests included the measurement of the insertion loss between two identical dipole
antennas and their radiation pattern. The results obtained show a good agreement
betweenthesimulationandexperimentalresults.
Non-visiblelightunderwateropticalcommunications
NormanFarr(WoodsHoleOceanographicInstitution)
CliffordPontbriand(WoodsHoleOceanographicInstitution)
JonathanWare(WoodsHoleOceanographicInstitution)
Leo-PaulPelletier(WoodsHoleOceanographicInstitution)
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One look at the absorption curve for light in water suggests that the best possible
windowforunderwateropticaltransmissionisattheblue-greenendofthevisiblelight
spectrum,centeredatroughly450nmforclear,deepwater,andshiftedmoretowards
green for coastal water. While this holds true for signal transmission in the optical
communications channel, it is also true for the solar spectrum, which presents as inbandwhitenoiseneartheoceansurface.Thegreatestsignallossandinterferenceisin
the 0 to 40 meter depth range, but solar irradiance is still present to a depth of 300
metersandinsomecasestoadepthof500meters.
Because solar radiation shares the same spectral band as the communications signal,
solar light is very difficult to reject without the loss of transmitted communications
signal.Forwide-angletransmittersandreceivers,dielectric,thin-film(TF)filtersarenot
effectiveduetothewavelengthdependenceonangleofincidence,thusmakingnarrowanglebandpassfiltersforunderwateruseverydifficulttodesign.Absorptivefilterscan
beusedtorejectlargeportionsofthevisiblespectrum,buttheproblemofin-bandnoise
still remains since absorptive filters do not exhibit the sharp cutoff of interference
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filters.
Sourcesintherangeof350to400nmpresentaviablemeanstoworkat,orjustbeyond,
the edge of the visible spectrum where a majority of sunlight can be rejected. Until
recently, efficient, inexpensive, near ultraviolet (NUV) sources have not been readily
available; but the demand for new, high power NUV light-emitting diodes (LEDs) for
commercialapplicationshasmadetheiruseinunderwaterapplicationspossible.These
wavelengths are not visible to the human eye thus making them good candidates for
non-visiblecommunications.
The Woods Hole Oceanographic Institution’s (WHOI’s) Optical Communications Group
hasperformedmanyfieldandlabexperimentswithshortwavelengthsforthepurpose
of wavelength division multiplexing (WDM), enhanced daylight performance, and nonvisible underwater communications. Initially 405 nm LEDs were used for WDM in
shallow water and then for long-range transmission tests in deep water at the Axial
SeamountoftheJuandeFucaRidge(JDR).Additionaltestswereperformedusing405
nmand385nmnearthesurfaceatJDRtoassessambientdaylightrejection.Recently,
work has been done in very shallow water in Cape Cod Bay to assess range with high
ambientlightinveryturbidwater.
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ArchitecturesandNovelStacks
(Chairs:TommasoMelodiaandPaoloCasari)
SEANetG3:High-Data-RateSoftware-DefinedUnderwaterAcousticNetworkPlatform
(“Off-the-record”paper)
EmrecanDemirors(NortheasternUniversity)
TommasoMelodia(NortheasternUniversity)
As of today, the underwater acoustic wireless communication platforms are mostly
based on inflexible hardware that can support mostly point-to-point, low-data-rate,
delay-tolerant applications. Regrettably, these devices do not provide neither the
sufficient data rates nor the necessary flexibility to support future underwater
networking applications and systems. To that end, we propose a new high-data rate
software-defined underwater acoustic networking platform, SEANet G3, with unique
characteristicsintermsofdatarate(megabit/sdataratesareforeseenovershortrange
links), spectrum agility, and hardware/software flexibility in support of distributed
networkedmonitoringoperations.Moreover,wedemonstratedataratesintheorderof
megabit/sonacontrolledlabenvironmentandforthefirsttimedataratesof522kbit/s
intheseaovershorthorizontallinks(e.g.10m)foraBERlowerthan10-3.
TheDESERTUnderwaterFrameworkv2:ImprovedCapabilitiesandExtensionTools
FilippoCampagnaro(UniversityofPadova)
RobertoFrancescon(UniversityofPadova)
FedericoFavaro(UniversityofPadova)
FedericoGuerra(UniversityofPadova)
PaoloCasari(IMDEANetworksInstitute)
RoeeDiamant(UniversityofHaifa)
MicheleZorzi(UniversityofPadova)
The DESERT Underwater emulation system (http://nautilus.dei.unipd.it/desertunderwater), originally designed for testing underwater acoustic networks, has been
recently extended. The new framework now includes multi-modal communication
functionalities encompassing low rate and high rate acoustics as well as optics, the
capabilityoftestingwirelesstelemetryforunderwaterequipment,aconnectiontothe
most recent version of the World Ocean Simulation System (WOSS), a modification to
the RECORDS system for sea trial remote control, and an interface between external
tools, e.g., Matlab, and the EvoLogics modem. In addition, experimental activities are
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now supported by an accurate real-time event scheduler which has been shown to
support, among others, long experiments involving time-division multiple-access
(TDMA)-basedMACprotocols.TheseadditionalprotocolschemesfromtheMACtothe
application layer (most of which have been tested in controlled environments and sea
trials) now make DESERT Underwater a comprehensive tool for underwater network
simulation and experimentation. In this paper, we present the new functionalities
developedoverthelasttwoyears.
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SecurityinUnderwaterCommunications
(Chairs:MauroConti,GianlucaDinniandRobertoPetroccia)
SecureUnderwaterAcousticNetworks:CurrentandFutureResearchDirections
ChhaganLal(UniversityofPadova)
RobertoPetroccia(CMRE)
MauroConti(UniversityofPadova)
JoãoAlves(CMRE)
UnderwaterAcousticNetworks(UANs)arewidelyusedinvariousapplicationssuchas
climate change monitoring, pollution control and tracking, tactical surveillance and
offshore exploration. However, limited consideration is given to the security of such
networks,despitethefactthattheuniquecharacteristicsofUANsmakethesenetworks
vulnerabletovariousmaliciousattacks.Inthispaper,weaddressfutureaspectsofhow
toimprovesecurityinUANs.Westartbyreviewinganddiscussingthestate-of-the-art
security threats for underwater networks along with their existing solutions. We then
identify the open research issues and challenges in the design of secure protocols for
communicationinUANs.Weproposeinnovativeapproachesbasedonnodecooperation,
cross-layering, software-defined cognitive networking and context-aware
communication in order to effectively provision new or strengthen existing security
frameworksinUANs.Byusingtheseapproaches,weaddresstheproblemofdetecting
maliciousbehavioursandroguenodesinordertoaddressthemajorsecurityissuesin
UANs.Wealsoinvestigatetheuseofacovertchannelbaseddetectionmechanismwhich
needstobeconsideredwhenmonitoringordeployingUANsatsea.Webelievethatthe
issuesraisedandfuturepossiblesolutionapproachesproposedinthispaperwillgreatly
helptheresearcherscontributingtowardsfortifyingsecurityinaninherentlyin-secure
UAN.
AnalyticalMetricWeightGenerationforMulti-DomainTrustinAutonomousUnderwater
MANETs
AndrewBolster(UniversityOfLiverpool)
AlanMarshall(UniversityOfLiverpool)
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Trust Management Frameworks (TMFs) are being used to improve the efficiency,
security, and reliability of de- centralized and distributed autonomous MANETs using
metrics garnered from the communications activities of nodes within the networks.
However, these do not perform well in sparse/harshenvironmentssuchasthose
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found in Underwater Acoustic Networks (UANs). As node capabilities increase, the
physical motion of nodes represent an additional domain of knowledge about the
operationsandbehavioursofthenetwork.InthispaperwepresentaMachineLearning
supported methodology for optimising metric weight vector generation, using metrics
from both physical and communications domains to detect and identify a range of
misbehaviours, demonstrating that by utilising information from multiple domains,
trust assessment can be more sensitive and accurate than in single-domain
(communications)assessment.
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