Full-Duplex for Underwater Acoustic Communications

Lead Research Organisation: University of York
Department Name: Electronics

Abstract

In recent years, there has been an immense interest in developing underwater acoustic communication (UAC) systems related to remote control and telemetry applications for the off-shore oil & gas industry. In practice, the only feasible method to achieve sub-sea communications is by means of acoustic signals. However, due to the limited bandwidth of the UAC channel, past research concentrated on the half-duplex (HD) mode of operation using time-division duplexing (TDD). Recently, full-duplex (FD) transmission attracted attention in wireless communications due to its potential to nearly double the throughput of single-hop wireless communication links. However, there is an evident absence of equivalent in-depth research in FD for UAC systems, despite the severe bandwidth limitations of the UAC channel. Hence, we outline 3 crucial challenges to be addressed in this research project:
Challenge 1-Understanding the Self Interference (SI) in FD UAC systems: FD comes with the promise of theoretically doubling the throughput. However, in practice, SI induced by the large power difference between the distant and local transmissions will result in signal to interference and noise loss, and in turn throughput performance degradation. For acoustic waveforms and UAC modems little is known with regard to the statistical properties of SI and the impact of non-ideal/non-linear characteristics of hardware components operating in FD mode. In order to design effective self interference cancellation (SIC) methods, a comprehensive understanding and accurate models of SI are required.
Challenge 2-SIC methods: To fully exploit the potential of FD transmission, effective SIC methods are required capable of providing cancellation up to approximately 100 dB. Passive and active SIC methods have been proposed for wireless communications, however, they have not been investigated at all for UAC waveforms, and we believe that there is significant potential in their utilisation, as well as in developing new and improved approaches.
Challenge 3-To realise the benefits of FD in UAC networks: The enhanced physical layer capability offered by FD links can only be fully realised if the medium access control (MAC) layer is suitably designed for simultaneous transmission and reception on the same frequency channel. This calls for highly adaptive scheduling based on varying traffic demands, channel conditions and local interference. The long propagation delays demand efficient assignment of capacity using methods adopted for satellite systems, including free, predictive assignment of capacity, and FD-enabled physical layer network coding.

To address these challenges we propose 5 work packages (WP) at Newcastle University (NU) and University of York (UoY) with the aim to design an FD-enabled UAC system that nearly doubles the throughput of equivalent HD systems under the same power and bandwidth constraints. WP A (NU) will study the effects of SI for UAC waveforms and hardware, and provide analytical models capturing the characteristics of SI. WP B (UoY) will study the performance of joint analog and digital SIC and beamforming methods to enable FD operation of acoustic modems. WP C (NU) and WP D (UoY) will investigate the design and performance of FD single and multi-hop relaying methods at physical layer and efficient MAC protocols. WP E (NU) will be used for experimental validation, refinement and integration of the proposed FD system. Experiments will be carried out in the anechoic water tank at NU and using full-scale sea trials conducted in the North Sea in realistic shallow-water channels using NU's research vessel.

The research in this proposal is potentially transformative and will contribute to the development of FD-based underwater networking and communication capabilities required by applications such as oil & gas exploration, oceanographic data collection, pollution monitoring, disaster prevention, and security.
 
Description This project is developing full-duplex technologies to allow simultaneous transmission and reception of signals at the same frequencies. Current systems are limited to using separate frequencies or non-simultaneous transmission. Full-duplex capability could provide up to twice the capacity for communications, for example. A key challenge to achieve full-duplex communication is cancellation of the strong interference from the transmitter into the receiver. A key outcome of the project so far has been effective reduction in the power of this interference to 1/7000000 th in practical experiments conducted in a water tank.

It has been found that the main challenges in providing the full-duplex capability include the time variability of the self-interference channel and nonlinearities in the transmitter and the receiver. New techniques have been proposed for dealing with these challenges. Specifically, a new class of adaptive filtering algorithms has been proposed that significantly improves the cancellation performance compared to classical adaptive filters in fast time-varying channels. A special scheme was proposed to deal with the nonlinearity of the power amplifier at the transmitter. Also, a nonlinear adaptive equaliser has been proposed to deal with the nonlinearity of the preamplifier in the receiver.
Exploitation Route To be fully defined later in the project. The currently developed capability would allow significantly increased communications capacity for short range underwater acoustic systems, for example, for spread spectrum systems operating at low signal to noise ratio.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Electronics

 
Description Cyber security for underwater communication
Amount £7,000 (GBP)
Organisation British Council 
Sector Charity/Non Profit
Country United Kingdom
Start 06/2019 
End 12/2019
 
Description High bandwidth covert (low probability of intercept) underwater acoustic communication
Amount £117,500 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 10/2019 
End 09/2023
 
Description Image processing for sonar applications
Amount £28,968 (GBP)
Organisation University of York 
Sector Academic/University
Country United Kingdom
Start 03/2019 
End 12/2019
 
Description Innovating the future of bio-inspired autonomous robot fish for offshore renewable energy inspection
Amount £10,985 (GBP)
Organisation White Rose University Consortium 
Sector Academic/University
Country United Kingdom
Start  
 
Description Maritime autonomous system anti-submarine barrier (Phase 1)
Amount £100,000 (GBP)
Organisation Defence Science & Technology Laboratory (DSTL) 
Sector Public
Country United Kingdom
Start 10/2018 
End 11/2019
 
Description Progeny Framework Task 19ss, Phorcys Phase 1: Work Package 3 - Networking
Amount £68,706 (GBP)
Organisation Thales Group 
Department Thales UK Limited
Sector Private
Country United Kingdom
Start 03/2020 
End 08/2020
 
Description York-Haifa Underwater Acoustic Communications Experiments
Amount £6,000 (GBP)
Organisation The Royal Society 
Sector Charity/Non Profit
Country United Kingdom
Start 11/2018 
End 11/2019
 
Title Waymark simulator 
Description Software simulator for virtual full-duplex signal transmission in the underwater acoustic channel. 
Type Of Material Improvements to research infrastructure 
Year Produced 2018 
Provided To Others? Yes  
Impact The development cycle for full-duplex techniques has been significantly reduced. A wider variety of underwater scenarios can now be investigated. Investigation of full-duplex techniques in totally controllable environments is now possible. Full-duplex techniques can now be compared in exactly the same acoustic environments and conditions. 
URL https://www.york.ac.uk/electronic-engineering/research/communication-technologies/underwater-network...
 
Description Harbin University 
Organisation Harbin Engineering University
Country China 
Sector Academic/University 
PI Contribution This is a collaboration with several research groups within the Harbin Engineering University. Several academic visitors were hosted by my research team. Due to this collaboration, a number of joint journal and conference papers have been published.
Collaborator Contribution A number of joint journal and conference papers have been published.
Impact Some of the jointly published papers: 1. Y. Zhang, J. Li, Y. Zakharov, X. Li, and J. Li, "Deep learning based underwater acoustic OFDM communications", Applied Acoustics, Elsevier, vol.154, 01 Nov 2019, pp. 53 - 58. 2. Y. Zhang, T. Wu, Y. Zakharov, and J. Li, "MMP-DCD-CV based sparse channel estimation algorithm for underwater acoustic transform domain communication system", Applied Acoustics, Elsevier, vol.154, 01 Nov 2019, pp. 43 - 52. 3. Q. Wu, Y. Li, Y. Zakharov, W. Xue, and W. Shi, "A kernel affine projection-like algorithm in reproducing kernel Hilbert space", IEEE Transactions on Circuits and Systems II: Express Briefs, published on 15 Oct 2019, pp.1-5. DOI: 10.1109/TCSII.2019.2947317 4. X. Zhang, T. Jiang, Y. Li, and Y. Zakharov, "A novel block sparse reconstruction method for DOA estimation with unknown mutual coupling", IEEE Communications Letters, vol. 23, No. 10, 17 July 2019, pp. 1845 - 1848. 5. Y. Zhang, J. Li, Y. Zakharov, J. Li, Y. Li, C. Lin, and X. Li, "Deep learning based single carrier communications over time-varying underwater acoustic channel", IEEE Access, vol. 7, 20 March 2019, pp. 38420 - 38430. 6. Y. Zhang, Y. Zakharov, and J. Li, "Soft-decision-driven sparse channel estimation and turbo equalization for MIMO underwater acoustic communications", IEEE Access, vol.6, 17 Jan 2018, pp. 4955 - 4973.
Start Year 2017
 
Description IMT Atlantique 
Organisation IMT Atlantique
Country France 
Sector Academic/University 
PI Contribution Hosted PhD researcher at the University of York for a period of 3 months. Gave invited talk at IMT Atlantique. Jointly wrote proposal for PhD studentship for funding from DGA/DSTL. Contributed to a joint conference paper, presented at UCOMMS 2018.
Collaborator Contribution Two researchers visited our research group. Jointly wrote proposal for PhD studentship for funding from DGA/DSTL. Prepared joint conference paper, presented at UCOMMS 2018.
Impact Conference paper published at UCOMMS conference 2018.
Start Year 2017
 
Description NATO-CMRE 
Organisation NATO Centre for Maritime Research and Experimentation
Country Italy 
Sector Public 
PI Contribution Invited a colleague to organise a special session at the UACE conference 2019. Invited a colleague to co-edit a special issue of the MDPI Journal on Sensor and Actuator Networks on the subject of underwater networking.
Collaborator Contribution Participation in conference special session organisation and journal special issue.
Impact Organisation of conference special session and journal special issue.
Start Year 2017
 
Description Thales UK 
Organisation Thales Group
Department Thales UK Limited
Country United Kingdom 
Sector Private 
PI Contribution Visibility of our research activities at York.
Collaborator Contribution Thales are supporting research proposals by offering use of trials facilties, access and loan of equipment, staff time etc. They are part funding an EPSRC iCASE studentship.
Impact iCASE award.
Start Year 2018
 
Description University of Haifa 
Organisation University of Haifa
Country Israel 
Sector Academic/University 
PI Contribution Invited to give a presentation at a workshop organised by the University of Haifa. Have a joint project funded by the Royal Society. Provided signals and planned sea experiments for a joint paper.
Collaborator Contribution Have a joint project funded by the Royal Society. Carried out sea experiments for a joint paper.
Impact Royal Society grant successful. Journal paper submitted to IEEE Journal of Oceanic Engineering.
Start Year 2018
 
Description XIamen University 
Organisation Xiamen University
Country China 
Sector Academic/University 
PI Contribution Prepared signals and planned sea experiment. Prepared two papers.
Collaborator Contribution Carried out sea and water tank experiments and contributed to two joint papers.
Impact Published paper in UCOMMS conference 2018. Submitted journal paper to IEEE Journal of Oceanic Engineering.
Start Year 2017
 
Description Attendance (with stand) of UK-RAS International Robotics Showcase 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact This event brought the international community together on the subject of robotics and autonomous systems, including use of such systems in marine environments.
Year(s) Of Engagement Activity 2019
URL https://www.ukras.org/robotics-week/international-robotics-showcase-2019-programme/
 
Description DSTL workshop on underwater communications 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Ben Henson, Nils Morozs and Paul Mitchell contributed to sessions on underwater acoustic communications and led a session on underwater networking for this workshop held at the National Oceanographic centre.
Year(s) Of Engagement Activity 2018
 
Description Invited talk (with associated paper) at the Underwater Acoustics Conference & Exhibition 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk abstract:

Full-duplex (FD) underwater acoustic (UWA) communication has significant
potential in increasing the capacity of acoustic links, but it suffers from severe self-interference
(SI) caused by the near-end transmission. Existing SI cancellation techniques include analogue
cancellation, digital cancellation and antenna beamforming. Among those techniques, the
digital cancellation has the lowest complexity. However, the reported digital SI cancellation
performance is limited. To achieve a higher performance, the non-linearity of power amplifier
(PA) should be taken into account. Here we use the digitalized PA output as the reference
signal for SI estimation to reduce the effect of the non-linear distortions. Such a system
architecture allows us to use a low-complexity linear adaptive filter for SI cancellation.
Specifically, we use the recursive least-squares (RLS) algorithm with dichotomous coordinate
descent (DCD) iterations. This results in a low-complexity SI canceller. As observed from the
experimental results, the choice of the sampling time is crucial to the SI cancellation

performance. In this paper, we present the digital SI cancellation scheme based on the RLS-
DCD algorithm with the use of PA output. To achieve robust SI cancellation performance, the

PA output is oversampled to twice of the symbol rate, de-multiplexed into two branches with
digital SI cancellation, and then combined based on the residual variance estimates in the two
branches. The SI cancellation performance is investigated by conducting experiments in an
indoor water tank and in a shallow lake. The tank experiments show that up to 66 dB of SI can
be cancelled using the proposed scheme, which is high compared to existing FD designs.
Meanwhile, up to 56 dB of SI is cancelled in the lake experiments. The difference in the SI
cancellation performance is due to faster varying SI channels in the lake experiments. Both the
water tank and lake experimental results show robust SI cancellation performance of the
proposed scheme regardless of the choice of sampling time.
Year(s) Of Engagement Activity 2019
URL http://www.uaconferences.org/
 
Description Invited workshop presentation at DSTL Fort Halstead 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact A presentation was given on underwater acoustic network research developments in a plenary session.
Year(s) Of Engagement Activity 2018
 
Description JANUS NATO standard workshop 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact To bring together experts to discuss developments with regard to standards for underwater acoustic communication, including future requirements.
Year(s) Of Engagement Activity 2018
 
Description Member of CETO Community 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Working group set up by DSTL to bring together interested and active parties involved in underwater communications.
Year(s) Of Engagement Activity 2018
 
Description Plenary conference talk 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Abstract of invited talk:

The underwater environment makes the design and deployment of networks particularly challenging. Acoustic signals provide a means of communicating over long distances, but the available bandwidth (and thereby fundamental capacity) is limited, especially over a longer range. Time-varying multi-path propagation generates significant spatial and temporal variation in received signal power, and the slow propagation speed of acoustic waves introduces significant latency. Achieving reliable and efficient communication is dependent on a suitably designed medium access control protocol, and in many instances, a multi-hop routing protocol.

This talk will provide an insight into alternative approaches in medium access control, showing how some of the underlying challenges can be addressed for particular types of network. A distinct approach to underwater networking will be proposed, based upon the use of reinforcement learning to provide inherent adaptation to time-varying conditions in distributed networks. An example will show how reinforcement learning can be used to provide efficient medium access control.
Year(s) Of Engagement Activity 2019
URL https://wuwnet.acm.org/2019/
 
Description Progeny Framework 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact We are a member of this framework run by QinetiQ. It's purpose is to manage and coordinate projects for DSTL, with members of the framework collaborating and bidding for DSTL funds in underwater and above water maritime systems.
Year(s) Of Engagement Activity 2018