Vertical underwater acoustic (UWA) communications play a crucial role in deep-sea applications. A vertical UWA channel generally features a moderate multipath but with time-varying Doppler shifts as well as loud impulsive noise. To achieve a robust vertical single-carrier UWA communication, this paper proposes an enhanced iterative receiver. First, a spline interpolation-based timing estimation approach is proposed to compensate for the time-varying Doppler effects efficiently. Then, the residual timing errors and the multipath interference are tackled by a fractionally spaced self-iterative soft equalizer (SISE) based on the vector approximate message passing (VAMP) algorithm. The VAMP-SISE consists of four parts: an inner soft slicer and an inner soft equalizer for symbol detection as well as a denoiser and a minimum mean-squared error estimator for impulsive noise suppression. Different parts iteratively exchange extrinsic information to improve the equalization performance. Last, a channel-fitting irregular convolutional code and a unity-rate code are employed at the transmitter to lower the signal-to-noise ratio threshold for reliable communications. Deep-sea experiments verify the performance superiority of the proposed receiver over existing schemes.

1.
J. W.
Choi
,
T. J.
Riedl
,
K.
Kim
,
A. C.
Singer
, and
J. C.
Preisig
, “
Adaptive linear turbo equalization over doubly selective channels
,”
IEEE J. Ocean. Eng.
36
(
4
),
473
489
(
2011
).
2.
A.
Yellepeddi
and
J. C.
Preisig
, “
Adaptive equalization in a turbo loop
,”
IEEE Trans. Wireless Commun.
14
(
9
),
5111
5122
(
2015
).
3.
D.
Li
,
Y.
Wu
,
M.
Zhu
, and
X.
Wu
, “
Efficient faster-than-Nyquist transceiver design for underwater acoustic communications
,” in
Proceedings of the International Conference on Underwater Networks and Systems (WUWNet)
(
2019
), pp.
1
5
.
4.
W.
Duan
,
J.
Tao
, and
Y. R.
Zheng
, “
Efficient adaptive turbo equalization for multiple-input multiple-output underwater acoustic communications
,”
IEEE J. Ocean. Eng.
43
(
3
),
792
804
(
2018
).
5.
J.
Tao
,
Y.
Wu
,
X.
Wang
, and
X.
Luo
, “
Comparison of sparsity-aware LMS adaptive equalization for underwater acoustic communications
,” in
2018 OCEANS – MTS/IEEE Kobe Techno-Oceans (OTO)
(
2018
), pp.
1
5
.
6.
J.
Tao
,
Y.
Wu
,
Q.
Wu
, and
X.
Han
, “
Kalman filter based equalization for underwater acoustic communications
,” in
OCEANS 2019 – Marseille
(
2019
), pp.
1
5
.
7.
J.
Tao
,
Y.
Wu
,
X.
Han
, and
K.
Pelekanakis
, “
Sparse direct adaptive equalization for single-carrier MIMO underwater acoustic communications
,”
IEEE J. Ocean. Eng.
45
(
4
),
1622
1631
(
2020
).
8.
Z.
Qin
,
J.
Tao
,
X.
Wang
,
X.
Luo
, and
X.
Han
, “
Direct adaptive equalization based on fast sparse recursive least squares algorithms for multiple-input multiple-output underwater acoustic communications
,”
J. Acoust. Soc. Am.
145
(
4
),
EL277
EL283
(
2019
).
9.
J.
Tao
,
J.
Wu
,
Y. R.
Zheng
, and
C.
Xiao
, “
Enhanced MIMO LMMSE turbo equalization: Algorithm, simulations, and undersea experimental results
,”
IEEE Trans. Signal Process.
59
(
8
),
3813
3823
(
2011
).
10.
L.
Wang
,
J.
Tao
, and
Y. R.
Zheng
, “
Single-carrier frequency-domain turbo equalization without cyclic prefix or zero padding for underwater acoustic communications
,”
J. Acoust. Soc. Am.
132
(
6
),
3809
3817
(
2012
).
11.
Y. R.
Zheng
,
J.
Wu
, and
C.
Xiao
, “
Turbo equalization for single-carrier underwater acoustic communications
,”
IEEE Commun. Mag.
53
(
11
),
79
87
(
2015
).
12.
Z.
Yang
and
Y. R.
Zheng
, “
Iterative channel estimation and turbo equalization for multiple-input multiple-output underwater acoustic communications
,”
IEEE J. Ocean. Eng.
41
(
1
),
232
242
(
2016
).
13.
X.
Tu
,
A.
Song
, and
X.
Xu
, “
Prefix-free frequency domain equalization for underwater acoustic single carrier transmissions
,”
IEEE Access
6
,
2578
2588
(
2018
).
14.
P.
Roberts
,
N.
Andronis
, and
A.
Ghiotto
, “
Voices from the deep—Acoustic communication with a submarine at the bottom of the Mariana Trench
,” in
Proceedings of Acoustics
(
2012
), pp.
1
4
.
15.
M.
Suzuki
,
T.
Sasaki
, and
T.
Tsuchiya
, “
Digital acoustic image transmission system for deep-sea research submersible
,” in
OCEANS 92 Proceedings: Mastering the Oceans Through Technology
(
1992
), Vol.
2
, pp.
567
570
.
16.
Y.-b.
Wu
,
M.
Zhu
,
T.
Liang
,
W.
Wang
,
B.
Yang
,
L.-y.
Zhang
,
X.-g.
Li
, and
Y.-y.
Liu
, “
Shipborne underwater acoustic communication system and sea trials with submersible Shenhai Yongshi
,”
China Ocean Eng.
32
(
6
),
746
754
(
2018
).
17.
W.
Zhu
,
M.
Zhu
,
Y.
Wu
,
B.
Yang
,
L.
Xu
,
X.
Fu
, and
F.
Pan
, “
Signal processing in underwater acoustic communication system for manned deep submersible ‘Jiaolong
,’”
Chin. J. Acoust.
32
(
1
),
1
15
(
2013
).
18.
M.
Zhu
,
Acoustic System of Jiaolong Manned Submersible and Its Future Development
(
Springer
Singapore, Singapore
,
2020
), pp.
171
186
.
19.
T.
Shimura
,
Y.
Kida
, and
M.
Deguchi
, “
High-rate acoustic communication at the data rate of 69 kbps over the range of 3,600 m developed for vertical uplink communication
,” in
OCEANS 2019 – Marseille
(
2019
), pp.
1
6
.
20.
L.
Freitag
,
M.
Johnson
, and
D.
Frye
, “
High-rate acoustic communications for ocean observatories-performance testing over a 3000 m vertical path
,” in
OCEANS 2000 MTS/IEEE Conference and Exhibition. Conference Proceedings
(
2000
), Vol.
2
, pp.
1443
1448
.
21.
J.
Gomes
and
V.
Barroso
, “
Acoustic channel equalization results for the ASIMOV high-speed coherent data link
,” in
OCEANS 2000 MTS/IEEE Conference and Exhibition. Conference Proceedings
(
2000
), Vol.
2
, pp.
1497
1442
.
22.
S.
Singh
,
S. E.
Webster
,
L.
Freitag
,
L. L.
Whitcomb
,
K.
Ball
,
J.
Bailey
, and
C.
Taylor
, “
Acoustic communication performance of the WHOI micro-modem in sea trials of the Nereus vehicle to 11,000 m depth
,” in
OCEANS 2009
(
2009
), pp.
1
6
.
23.
M.
Kurowski
,
E.
Rentzow
,
D.
Dewitz
,
T.
Jeinsch
,
B.
Lampe
,
S.
Ritz
,
R.
Kutz
,
F.
Boeck
,
S.
Neumann
, and
D.
Oertel
, “
Operational aspects of an ocean-going USV acting as communication node
,”
in Proceedings of the 15th Conference on Computer Applications and Information Technology in the Maritime Industries
(
2015
).
24.
D.
Li
,
Y.
Wu
, and
M.
Zhu
, “
Nonbinary LDPC code for noncoherent underwater acoustic communication under non-Gaussian noise
,” in
Proceedings of 2017 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC)
(
2017
), pp.
1
6
.
25.
Y.
Li
,
B.
Vucetic
, and
Y.
Sato
, “
Optimum soft-output detection for channels with intersymbol interference
,”
IEEE Trans. Inf. Theory
41
(
3
),
704
713
(
1995
).
26.
M.
Tüchler
, “
Design of serially concatenated systems depending on the block length
,”
IEEE Trans. Commun.
52
(
2
),
209
218
(
2004
).
27.
J.
Wang
,
S. X.
Ng
,
A.
Wolfgang
,
L. L.
Yang
,
S.
Chen
, and
L.
Hanzo
, “
Near-capacity three-stage MMSE turbo equalization using irregular convolutional codes
,” in
4th International Symposium on Turbo Codes & Related Topics; 6th International ITG-Conference on Source and Channel Coding
(
2006
), pp.
1
6
.
28.
H. V.
Nguyen
,
C.
Xu
,
S. X.
Ng
, and
L.
Hanzo
, “
Near-capacity wireless system design principles
,”
IEEE Commun. Surv. Tuts.
17
(
4
),
1806
1833
(
2015
).
29.
Y.
Yao
,
Y.
Wu
,
M.
Zhu
,
D.
Li
, and
J.
Tao
, “
Efficient on-off keying underwater acoustic communication for seafloor observation networks
,”
Appl. Sci.
10
(
6
),
1986
(
2020
).
30.
D.
Li
,
Y.
Wu
,
J.
Tao
, and
M.
Zhu
, “
Performance analysis and improvement for VAMP soft frequency-domain equalizers
,”
IEEE Access
7
,
42495
42506
(
2019
).
31.
S.
Şahin
,
A. M.
Cipriano
,
C.
Poulliat
, and
M.-L.
Boucheret
, “
A framework for iterative frequency domain EP-based receiver design
,”
IEEE Trans. Commun.
66
(
12
),
6478
6493
(
2018
).
32.
B. S.
Sharif
,
J.
Neasham
,
O. R.
Hinton
, and
A. E.
Adams
, “
A computationally efficient Doppler compensation system for underwater acoustic communications
,”
IEEE J. Ocean. Eng.
25
(
1
),
52
61
(
2000
).
33.
Z.
Lin
, “
Wideband ambiguity function of broadband signals
,”
J. Acoust. Soc. Am.
83
(
6
),
2108
2116
(
1988
).
34.
L.
Erup
,
F. M.
Gardner
, and
R. A.
Harris
, “
Interpolation in digital modems: II. Implementation and performance
,”
IEEE Trans. Commun.
41
(
6
),
998
1008
(
1993
).
35.
J.
Proakis
and
M.
Salehi
,
Digital Communications
, 5th ed. (
McGraw-Hill Higher Education
, New York, 2008), p.
654
.
36.
S.
Rangan
,
P.
Schniter
, and
A. K.
Fletcher
, “
Vector approximate message passing
,”
IEEE Trans. Inf. Theory
65
(
10
),
6664
6684
(
2019
).
37.
P.
Schniter
,
S.
Rangan
, and
A. K.
Fletcher
, “
Vector approximate message passing for the generalized linear model
,” in
Proceedings of 50th Asilomar Conference on Signals, Systems and Computers
(
2016
), pp.
1525
1529
.
38.
M.
Nassar
,
P.
Schniter
, and
B. L.
Evans
, “
A factor graph approach to joint OFDM channel estimation and decoding in impulsive noise environments
,”
IEEE Trans. Signal Process.
62
(
6
),
1576
1589
(
2014
).
39.
S.
Yang
,
G. B.
Deane
,
J. C.
Preisig
,
N. C.
Sevüktekin
,
J. W.
Choi
, and
A. C.
Singer
, “
On the reusability of postexperimental field data for underwater acoustic communications R&D
,”
IEEE J. Ocean. Eng.
44
(
4
),
912
931
(
2019
).
You do not currently have access to this content.