Multibranch Autocorrelation Method for Doppler Estimation in Underwater Acoustic Channels

Li, Jianghui; Zakharov, Yuriy; Henson, Benjamin

doi:10.1109/joe.2017.2761478

Cited by 55 publications

(47 citation statements)

References 39 publications

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“…3) also includes the packet detection, timing estimation and initial Doppler estimation applied to the LPE signal r LPE (n). These operations are based on the multi-branch autocorrelation Doppler estimator as described in our recent work [9].…”

Section: B Data Packet Detection and Doppler Estimationmentioning

confidence: 99%

“…For every sample r LPE (n), the 2D autocorrelation function is computed as explained in [9]; an example is shown in Fig. 4.…”

Section: B Data Packet Detection and Doppler Estimationmentioning

confidence: 99%

“…The receiver in the modem detects the data packet, finds the temporal centre of the packet and performs initial estimation of Doppler parameters, such as the linear and quadratic time compression factors. Such a model of the Doppler effect allows communication in scenarios with transmitter/receiver motion at high velocity and acceleration [9]. This processing is performed independently (blindly) of the specific pilot sequence incorporated into the data packet.…”

Section: Introductionmentioning

confidence: 99%

“…However, due to a large number of potential Doppler estimation channels, the CAF method is computationally intensive, even if fast Fourier transforms (FFTs) and a two-step (coarse and fine estimation) approach are used to speed up the computations [4], [14], [15]. In [9], [16], we have proposed a Doppler estimator that provides accurate estimates of Doppler compression factors due to the transmitter/receiver velocity and acceleration that requires significantly fewer computations than the CAF method. The design proposed in this paper is based on the Doppler estimator from [9], [16].…”

Section: Introductionmentioning

confidence: 99%

“…In [9], [16], we have proposed a Doppler estimator that provides accurate estimates of Doppler compression factors due to the transmitter/receiver velocity and acceleration that requires significantly fewer computations than the CAF method. The design proposed in this paper is based on the Doppler estimator from [9], [16].…”

Section: Introductionmentioning

confidence: 99%

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Low-Complexity UAC Modem and Data Packet Structure

Zakharov

Fei

Mitchell

et al. 2018

2018 Fourth Underwater Communications and Networking Conference (UComms)

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In underwater acoustic communication (UAC), the propagated signal undergoes severe multipath and Doppler distortions. The high overall complexity of UAC receivers is essentially due the Doppler estimation, channel estimation and equalization techniques required to deal with these effects. In this paper, we propose a novel data packet structure for transmission in underwater acoustic channels. This data structure allows the development of relatively simple estimation and equalization techniques, thus resulting in a low-complexity modem design. The data packet is based on single-carrier modulation with superimposed data and pilot symbols. The pilot symbol sequence is repeated within the packet, thus allowing application of the multi-branch autocorrelation Doppler estimation, possessing a low complexity and high accuracy. The data rate in the packet can easily be adjusted depending on the propagation conditions. The received packet is processed in the frequency domain, thus allowing low-complexity channel estimation and equalization. More specifically, in the example design, the channel estimation is based on local cubic B-splines. The modem has been evaluated using numerical simulation and experiments in a water tank, demonstrating successful performance of our design.

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Section: B Data Packet Detection and Doppler Estimationmentioning

confidence: 99%

“…For every sample r LPE (n), the 2D autocorrelation function is computed as explained in [9]; an example is shown in Fig. 4.…”

Section: B Data Packet Detection and Doppler Estimationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Low-Complexity UAC Modem and Data Packet Structure

Zakharov

Fei

Mitchell

et al. 2018

2018 Fourth Underwater Communications and Networking Conference (UComms)

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Synchronization techniques for underwater acoustic communications

Babu

Ameer

Koilpillai

2023

Int J Communication

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SummaryUnderwater acoustic channel is a challenging medium for communication due to the presence of significant multipath, high noise, frequency‐dependent propagation loss, and high and non‐uniform Doppler spread. Doppler shift is non‐negligible in underwater communication due to the low velocity of underwater signals. Synchronization and Doppler estimation are important requirements for achieving good performance in this channel. Synchronization algorithms that give good performance in radio communication do not work well in underwater communication. Hence, this area has received a lot of attention from researchers. This paper surveys important works in the area. The techniques proposed in the literature for frame synchronization, frequency and phase synchronization, and timing synchronization in single carrier communications are reviewed here. The synchronization techniques proposed for OFDM, MIMO OFDM, and spread spectrum communication are also surveyed. Doppler estimation methods proposed in the literature are also reviewed. It is found that most of the recent works in underwater acoustic communication focus on OFDM synchronization. Deep learning‐based methods proposed in the literature are also reviewed. Key open problems and areas that require future research attention in the field of synchronization and Doppler estimation in underwater communications are highlighted in this paper. The area needing most attention of underwater communication researchers was found to be MIMO OFDM due to the difficulty in synchronization in such systems while used in underwater communication. Reducing the computational complexity of the algorithms used is also important for future work. Schemes that work with Doppler due to relative velocity over 10 m/s also need to be developed.

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