Diamant Lutz Lampe Emmett Gamroth Low Probability of Detection for Underwater Acoustic Communication Networks 2 Motivation LPD not LPI Applications Military quite sonar UWAC ID: 320343
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Slide1
Roee Diamant, Lutz Lampe, Emmett Gamroth
Low Probability of Detection for Underwater Acoustic Communication
NetworksSlide2
2
Motivation
LPD not LPI !
Applications:
Military – “quite” sonar, UWACSafety & Environment – regulations are dB/HzLack of clear definition – what is LPD?Low SNR?Blend in noise?LPD by who?
Objective: representation of LPDSlide3
3
Methods for LPD UWAC
Direct Sequence Spread Spectrum (DSSS):
random phase
[Ling:2010]Chaotic sequence [Lei:2011]OFDM – close bands + slow Tx rate [Leus:2008]Focusing: time reversal [Yang:2008], MIMO [Zhu:2006]
Frequency
PSD
noise level
Frequency
PSD
noise level
Dispreading:
Spreading:
Interceptor:
Receiver:Slide4
4
Quality Measures
Determine if a comm. System is LPD
Alternatives:
We use:captures target Pd, Pfa of interceptor, and Pe of receiverNot related to Tx powerLPD - for each , define Truly covert - , Good LPD - Slide5
5Slide6
6
LPD Comm. System – a Test Case
Simple attenuation model:
Model used to set upper and lower bounds on LPD!
SNPR at distance r from Tx:Assuming similar at Rx and In, we getIf are similar :Slide7
7
Capabilities: Receiver and Interceptor
Interceptor – energy detection:
Interceptor SNPR (ROC):
Receiver detection (ROC):Receiver decoding: Slide8
8
Simulation
Parameters:
MPSK DSSS vs. Energy detector
Channel ParametersSpreading factorSlide9
9
Sea Trial
Vancouver Island -
Saanich
InletVessels:Transmitter – fixed buoy (Ocean Technology Test Bed, UVIC)Receiver – drifting vesselInterceptor– maneuvering vesselProcedure:Find Tx-Rx range (max s.t. BER = 0)Find Tx-In range (max s.t. detect)Slide10
10
Sea Trial - Results
Fc
= 40kHz
Fc
= 30kHz True LPD is possible!Slide11
11
Summery
Channel Effect:
LPD inversely proportional to carrier frequency
( )LPD better in shallow water ( ) Communication Effect:LPD increases with spreading factor (K),LPD decreases as Tx rate increaseLPD inversely proportional to number of symbols (N)True LPD is possible! (validated in sea trial)
Thank you!Slide12
12
Reference
J. Ling, H. He, J. Li, W. Roberts, and P.
Stoica
, “Covert underwater acoustic communications:
Transciever structures, waveform designs and associated performances,” Journal of Acoustical Society of America, vol. 128, no. 5, p. 2898-2909, Nov. 2010. L. Lei and F. Xu, “A chaotic direct sequence spread spectrum communication system in shallow water,” in International Conference on Control, Automation and Systems Engineering (CASE), Singapore, Jul. 2011. G. Leus, P. Walree, J. Boschma, C. Franciullacci, H. Gerritsen, and P. Tusoni, “Covert underwater communication with muliband OFDM,” in IEEE OCEANS, Quebec City, Canada, Sep. 2008. W. Zhu, B. Daneshrad, J. Bhatia, and K. Hun-Seok, “MIMO systems for military communications,” in IEEE Military Communications Conference (MILCOM), Washington, DC, Oct. 2006. T. Yang and W. Yang, “Performance analysis of direct-sequence spread-spectrum underwater acoustic communicationswith low signal-to-noise-ratio input signals,” Journal of Acoustical Society of America, vol. 123, no. 2, pp. 842–855, Feb. 2008. S. Blunt, J. Metcalf, C. Biggs, and E.
Perrins, “
Perforamnce
charectaristics
and metrics for intra-pulse radar-embedded communication,” IEEE J. Select. Areas Commun., vol. 29, no. 10, pp. 2057–2066, Dec. 2011.P. Walree, T. Ludwig, C. Solberg, E. Sangfelt, A. Laine, G. Bertolotto, and A. Ishøy, “UUV covert acoustic
communicatios
,” in
Underwater
Defence Technologies (UDT), Hamburg, Germany, 2006.
C. Liao and T. Woo, “Adaptation from transmission security (TRANSEC) to cognitive radio communication,” in
Advances in Cognitive Radio Systems. InTech, 2012, pp. 81–104.