A transceiver architecture for ultrasonic OFDM with adaptive Doppler compensation

MinhHai, Tran; Saotome, Rie; Taisuki, Suzuki; Wada, Tomohisa

doi:10.23919/oceans.2015.7401805

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…We then used time-domain resampling, which has been a very powerful tool to alleviate nonuniform Doppler shifts [26]. • Similar to other conventional two-step approaches to alleviate the Doppler effect, the coarse-and the fine compensation phase will be used to compensate CFO and Doppler shifts, respectively [33], [34]. As illustrated in [33], the resampling besides being effective in ununiform Doppler shift compensation, will increase the FFT size significantly.…”

Section: Introductionmentioning

confidence: 99%

“…Agreed, the oversized FFT problem is theoretically still be accurately handled through digital signal processing [26]. However, the utilization of the ICI matrix inversion with the computational complexity of O(N 2 ) will be a problem at the receiver [34]. The main difference of this study is to use nonuniform fast Fourier transform (NFFT) in choosing the sampling points to construct a fast and stable Doppler frequency Compensation Matrix-based NFFT (DCMN) to fine compensate the Doppler phase shift.…”

Section: Introductionmentioning

confidence: 99%

“…By doing so, we have combined the IFFT operation with the Doppler frequency compensation. Thus, the receiver complexity of our proposal is significantly reduced when compared with the state of the art [34], [39]. • The remaining contribution of this study is to present a test-bed UWA-OFDM with a transmission distance of more than 1km.…”

Section: Introductionmentioning

confidence: 99%

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Low Complexity Non-Uniform FFT for Doppler Compensation in OFDM-Based Underwater Acoustic Communication Systems

et al. 2022

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The Doppler effect critically degrades the performance of orthogonal frequency division multiplexing (OFDM) systems in general. This problem is significantly worse for underwater acoustic (UWA) communication systems due to the distinct characteristics of the underwater channel, resulting in the loss of orthogonality among sub-carriers. In order to compensate Doppler shifts, including phase noise and multipath channels in realistic communication scenarios, the joint of channel estimation and ICI reduction is often performed. However, the accuracy depends on the channel estimation and the FFT size, while this leads to increased computational complexity at the receiver. To achieve this dual goal in the actual underwater communication environment, a novel pilot structure in the frequency domain has been applied to overcome the channel impulse response (CIR) variation in a block period. The coarse Doppler shift is firstly estimated by using the received pilot signal. Afterward, the study takes advantage of the flexibility provided by non-uniform fast Fourier transform (NFFT) in choosing the sampling points to construct a fast and stable Doppler frequency Compensation Matrix-based NFFT (DCMN) to fine compensate the Doppler phase shift. Finally, this study shows the improvement of the proposed method's performance by actual experimental measurements and simulations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low Complexity Non-Uniform FFT for Doppler Compensation in OFDM-Based Underwater Acoustic Communication Systems

et al. 2022

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“…The OFDM technique is widely used thanks to its ability to eliminate the inter-symbol interference (ISI) which is caused by a large delay spread [5,6]. However, OFDM systems are very easily influenced by the Doppler shifts that result in the so-called inter-carrier interference (ICI) and degrade the system performance dramatically [7].…”

Section: Introductionmentioning

confidence: 99%

Impact of Inter-Channel Interference on Shallow Underwater Acoustic OFDM Systems

Nguyen

2020

MIC ICT Research Journal

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This paper investigates the impacts of Inter-Channel Interference (ICI) effects on a shallow underwater acoustic (UWA) orthogonal frequency-division multiplexing (OFDM) communication system. Considering both the turbulence of the water surface and the roughness of the bottom, a stochastic geometry-based channel model utilized for a wide-band transmission scenario has been exploited to derive a simulation model. Since the system bandwidth and the sub-carrier spacing is very limited in the range of a few kHz, the channel capacity of a UWA system is severely suffered by the ICI and Doppler effects. For further investigation, we construct the signal-to-noise-plus-interference ratio (SINR) based on the simulation model, then evaluate the channel capacity. Numerical results show that the various factors of a UWA-OFDM system as subcarriers, bandwidth, and OFDM symbols affects the channel capacity under the different Doppler frequencies. Those observations give hints to select the good parameters for UWA-OFDM systems.

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Method of selecting signals with spatial-temporal diversity for underwater communication using OFDM technique

Hung

Khương

Trung

et al. 2022

JMST

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In this paper, we propose a reliable communication solution using space-time diversity technique but using only one transceiver antenna applied to mobile OFDM system in underwater communication environment. In our solution, instead of using multiple receive antennas, the transmitter transmits an OFDM signal N times consecutively. The moving transmitter during sending OFDM frames will creat both spatial and temporal diversity of the received signal. To decode the signal from N received OFDM signal frames, we propose an optimal frame selection method to increase efficiency as well as save decoding time. The simulation and experimental results show that the system can achieve a better SER error rate than the MRC technique applied to N received data frames and the number of calculations in our algorithm is also less than that of combination maximum cases of N frames.

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A transceiver architecture for ultrasonic OFDM with adaptive Doppler compensation

Cited by 3 publications

References 12 publications

Low Complexity Non-Uniform FFT for Doppler Compensation in OFDM-Based Underwater Acoustic Communication Systems

Low Complexity Non-Uniform FFT for Doppler Compensation in OFDM-Based Underwater Acoustic Communication Systems

Impact of Inter-Channel Interference on Shallow Underwater Acoustic OFDM Systems

Method of selecting signals with spatial-temporal diversity for underwater communication using OFDM technique

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