The Experts below are selected from a list of 49794 Experts worldwide ranked by ideXlab platform
Geert Leus - One of the best experts on this subject based on the ideXlab platform.
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underwater acoustic communication using multiple input multiple output doppler resilient Orthogonal Signal division multiplexing
IEEE Journal of Oceanic Engineering, 2020Co-Authors: Tadashi Ebihara, Hanako Ogasawara, Geert LeusAbstract:In this paper, we propose a novel underwater acoustic (UWA) communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) and multiple-input–multiple-output (MIMO) Signaling. We present both the transmitter processing and the receiver processing for MIMO D-OSDM. We evaluate the performance of MIMO D-OSDM in simulations with a large intersymbol interference of 25 symbols and a Doppler spread with a maximum Doppler shift of 8 Hz. In addition, the sea trial is performed in Suruga Bay, where the receiver is mounted on a barge and a research vessel with the transmitter makes round trips along a line with a speed of 4 kn. In the experiments, we obtain an intersymbol interference of 3.6–29.7 symbols and a Doppler spread of several Hertz (leading to a spread of over two to three subcarrier spacings). The simulation results suggest that MIMO D-OSDM has an advantage over normal D-OSDM, Doppler-resilient MIMO Orthogonal frequency division multiplexing (MIMO D-OFDM), and classical OFDM with MIMO Signaling (MIMO OFDM)—MIMO D-OSDM achieves better bit error rate performance than the benchmarks. The sea trial results also support the advantage of MIMO D-OSDM—it achieves a coded block error rate of 3.2% while normal D-OSDM and MIMO D-OFDM achieve a coded block error rate of 9.7% and 9.3%, respectively. We conclude that MIMO D-OSDM can become a viable technique that achieves reliable and effective UWA communication.
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equalization of osdm over time varying channels based on diagonal block banded matrix enhancement
Signal Processing, 2020Co-Authors: Jing Han, Yujie Wang, Zehui Gong, Geert LeusAbstract:Abstract Orthogonal Signal-division multiplexing (OSDM) has recently emerged as a promising alternative to Orthogonal frequency division multiplexing (OFDM) for high-rate wireless communications. Although providing more flexibility in system design, it suffers from a special interference structure, namely inter-vector interference (IVI), when channel time variations are present. In this paper, we first derive the general OSDM Signal model over time-varying channels, and then show that a time-domain window can be used to enhance the diagonal-block-banded (DBB) approximation of the channel matrix in a transformed domain. Furthermore, based on the DBB matrix enhancement, a low-complexity OSDM equalization algorithm is designed. Simulation results indicate that the proposed equalizer has significant performance advantages over that using the direct DBB approximation.
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low complexity equalization of Orthogonal Signal division multiplexing in doubly selective channels
IEEE Transactions on Signal Processing, 2019Co-Authors: Jing Han, Lingling Zhang, Qunfei Zhang, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a generalized modulation scheme to bridge the gap between Orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. It allows significantly more flexibility in system design; however, over doubly-selective channels, it suffers from a special Signal distortion structure, namely inter-vector interference, which is analogous to inter-carrier interference in conventional OFDM. To analyze its effect, in this paper, the complex exponential basis expansion model (CE-BEM) is used to approximate the doubly-selective channel. We show that the composite channel matrix of OSDM systems is cyclically block banded in this case, and the blocks in its main band can be further diagonalized. By exploiting this unique matrix structure, low-complexity block and serial OSDM equalization algorithms are then proposed. These two equalization algorithms are based on block LDL $^H$ factorization and block iterative matrix inversion, respectively, both of which are implemented in a transformed domain to avoid direct inversion of large matrices. In addition, a CE-BEM channel estimation method is designed for OSDM systems, which uses frequency-shifted Chu sequences as pilots to ease the computation. Numerical simulations are finally provided to justify the validity of our channel equalization and estimation algorithms.
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time domain oversampled Orthogonal Signal division multiplexing underwater acoustic communications
Journal of the Acoustical Society of America, 2019Co-Authors: Jing Han, Yujie Wang, Lingling Zhang, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a recently emerging modulation scheme which, compared to conventional Orthogonal frequency-division multiplexing, can effectively lower the peak-to-average power ratio and introduce intra-vector frequency diversity. In this paper, a time-domain oversampled OSDM system for underwater acoustic (UWA) communications is designed, where each OSDM vector is equivalently transmitted over multiple virtual channels, and thus an enhanced frequency diversity gain can be achieved. Moreover, at the receiver, zero vectors and frequency-shifted Chu sequences are used for Doppler compensation and channel estimation, respectively, while low-complexity per-vector equalization is performed based on the composite channel matrix factorization. Finally, the performance of the proposed OSDM system is evaluated through both numerical simulations and a short-range field experiment, and its effectiveness over time-varying UWA channels is confirmed.
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iterative per vector equalization for Orthogonal Signal division multiplexing over time varying underwater acoustic channels
IEEE Journal of Oceanic Engineering, 2019Co-Authors: Jing Han, Qunfei Zhang, Sundeep Prabhakar Chepuri, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a promising modulation scheme that provides a generalized framework to unify Orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. By partitioning each data block into vectors, it allows for a flexible configuration to trade off resource management flexibility with peak-to-average power ratio. In this paper, an OSDM system is proposed for underwater acoustic communications. The channel Doppler effect after front-end resampling is modeled as a common time-varying phase on all propagation paths. It leads to a special Signal distortion structure in the OSDM system, namely, intervector interference, which is analogous to the intercarrier interference in the conventional OFDM system. To counteract the related performance degradation, the OSDM receiver performs iterative detection, integrating joint channel impulse response and phase estimation, equalization, and decoding in a loop. Meanwhile, to avoid inversion of large matrices in channel equalization, frequency-domain per-vector equalization is designed, which can significantly reduce the computational complexity. Furthermore, the performance of the proposed OSDM system is evaluated through both numerical simulations and a field experiment, and its reliability over underwater acoustic channels is confirmed.
Consuelo Pizarro - One of the best experts on this subject based on the ideXlab platform.
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Prediction of organic acids and other quality parameters of wine vinegar by near-infrared spectroscopy. A feasibility study
Food Chemistry, 2006Co-Authors: María-josé Sáiz-abajo, José-maría González-sáiz, Consuelo PizarroAbstract:Abstract A method for quality control of wine vinegar has been developed based on near-infrared spectroscopy that can be applied to monitor processes or in quality control in vinegar industries. In vinegar production, stages such as on-line fermentation monitoring, dilution process and quality control of the final product are relevant and necessary. The aim of this study was to achieve and simplify these manufacturing stages through the determination of 14 parameters from a spectral measurement. Total acids, non-volatile and volatile acids, organic acids, l -proline, solids, ash and chloride in vinegar were determined by near-infrared spectroscopy. Different data pre-processing methods such as Orthogonal Signal correction, multiplicative scatter correction or column centering were used and the final multivariate methods were evaluated and compared. The calibration models were validated and prediction capacity studied in order to examine their practical applicability to the vinegar industry.
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Orthogonal Signal correction applied to the classification of wine and molasses vinegar samples by near-infrared spectroscopy. Feasibility study for the detection and quantification of adulterated vinegar samples
Analytical and Bioanalytical Chemistry, 2005Co-Authors: María-josé Sáiz-abajo, José-maría González-sáiz, Consuelo PizarroAbstract:The most common fraudulent practice in the vinegar industry is the addition of alcohol of different origins to the base wine used to produce wine vinegar with the objective of reducing manufacturing costs. The mixture is then sold commercially as genuine wine vinegar, thus constituting a fraud to consumers and an unfair practice with respect to the rest of the vinegar sector. A method based on near-infrared spectroscopy has been developed to discriminate between white wine vinegar and alcohol or molasses vinegar. Orthogonal Signal correction (OSC) was applied to a set of 96 vinegar NIR spectra from both original and artificial blends made in the laboratory, to remove information unrelated to a specific response. The specific response used to correct the spectra was the extent of adulteration of the vinegar samples. Both raw and corrected NIR spectra were used to develop separate classification models using the potential functions method as a class-modeling technique. The previous models were compared to evaluate the suitability of near-infrared spectroscopy as a rapid method for discrimination between vinegar origin. The transformation of vinegar NIR spectra by means of an Orthogonal Signal-correction method resulted in notable improvement of the specificity of the constructed classification models. The same Orthogonal correction approach was also used to perform a calibration model able to detect and quantify the amount of exogenous alcohol added to the commercial product. This regression model can be used to quantify the extent of adulteration of new vinegar samples.
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Classification of wine and alcohol vinegar samples based on near-infrared spectroscopy. Feasibility study on the detection of adulterated vinegar samples.
Journal of agricultural and food chemistry, 2004Co-Authors: María-josé Sáiz-abajo, José-maría Gonzales-saiz, Consuelo PizarroAbstract:Near-infrared (NIR) spectroscopy was used to discriminate between wine vinegar (red or white) and alcohol vinegar. One Orthogonal Signal correction method (OSC) was applied on a set of 73 vinegar NIR spectra from both origins and artificial blends made in the laboratory in order to remove information unrelated to a specific chemical response (tartaric acid), which was selected due to its high discriminant ability to differentiate between wine vinegar and alcohol vinegar samples. These corrected NIR spectra, as well as raw NIR spectra and 14 physicochemical variables, were used to develop separate classification models using the potential functions method as a class-modeling technique. The aforementioned models were compared to evaluate the suitability of NIR spectroscopy as a rapid method for discriminating between vinegar origins. The transformation of vinegar NIR spectra by means of an Orthogonal Signal correction method prompted a notable improvement in the specificity of the constructed classification models. The classification model developed was then applied to artificial vinegar blends made in the laboratory to test its capacity to recognize adulterated vinegar samples.
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an evaluation of Orthogonal Signal correction methods for the characterisation of arabica and robusta coffee varieties by nirs
Analytica Chimica Acta, 2004Co-Authors: I Estebandiez, J M Gonzalezsaiz, Consuelo PizarroAbstract:Two Orthogonal Signal correction methods (OSC and DOSC) were applied on a set of 83 roasted coffee NIR spectra from varied origins and varieties in order to remove information unrelated to a specific chemical response (caffeine), which was selected due to its high discriminant ability to differentiate between arabica and robusta coffee varieties. These corrected NIR spectra, as well as raw NIR spectra and three chemical quantities (caffeine, chlorogenic acids and total acidity), were used to develop separate classification models accordingly using the potential functions method as a class-modelling technique in order to evaluate their respective capacities to discriminate between coffee varieties and the influence of these pre-processing methods on the classification of the coffee samples into their corresponding variety class. The transformation of roasted coffee NIR spectra by means of an Orthogonal Signal correction method, taking into account in this correction a chemical response closely related to the sample origin, prompted a notable improvement in the specificity of the constructed classification models.
Tadashi Ebihara - One of the best experts on this subject based on the ideXlab platform.
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underwater acoustic communication using multiple input multiple output doppler resilient Orthogonal Signal division multiplexing
IEEE Journal of Oceanic Engineering, 2020Co-Authors: Tadashi Ebihara, Hanako Ogasawara, Geert LeusAbstract:In this paper, we propose a novel underwater acoustic (UWA) communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) and multiple-input–multiple-output (MIMO) Signaling. We present both the transmitter processing and the receiver processing for MIMO D-OSDM. We evaluate the performance of MIMO D-OSDM in simulations with a large intersymbol interference of 25 symbols and a Doppler spread with a maximum Doppler shift of 8 Hz. In addition, the sea trial is performed in Suruga Bay, where the receiver is mounted on a barge and a research vessel with the transmitter makes round trips along a line with a speed of 4 kn. In the experiments, we obtain an intersymbol interference of 3.6–29.7 symbols and a Doppler spread of several Hertz (leading to a spread of over two to three subcarrier spacings). The simulation results suggest that MIMO D-OSDM has an advantage over normal D-OSDM, Doppler-resilient MIMO Orthogonal frequency division multiplexing (MIMO D-OFDM), and classical OFDM with MIMO Signaling (MIMO OFDM)—MIMO D-OSDM achieves better bit error rate performance than the benchmarks. The sea trial results also support the advantage of MIMO D-OSDM—it achieves a coded block error rate of 3.2% while normal D-OSDM and MIMO D-OFDM achieve a coded block error rate of 9.7% and 9.3%, respectively. We conclude that MIMO D-OSDM can become a viable technique that achieves reliable and effective UWA communication.
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underwater acoustic communication using multiple input multiple output doppler resilient Orthogonal Signal division multiplexing
OCEANS Conference, 2018Co-Authors: Tadashi Ebihara, Geert Leus, Hanako OgasawaraAbstract:In this paper, we propose a novel underwater acoustic communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) and multiple-input multiple-output (MIMO) Signaling. We present both the transmitter and receiver processing for MIMO D-OSDM. We evaluate the performance of MIMO D-OSDM in simulations with a large inter-symbol interference (60 symbols) and Doppler spread (maximum Doppler shift of 15 Hz). The simulation results show that MIMO D-OSDM achieves almost the same energy efficiency as normal D-OSDM while doubling the spectrum efficiency. We conclude that MIMO D-OSDM can become a viable technique that achieves reliable and effective UWA communication.
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underwater acoustic communication using doppler resilient Orthogonal Signal division multiplexing in a harbor environment
Physical Communication, 2018Co-Authors: Tadashi Ebihara, Geert Leus, Hanako OgasawaraAbstract:Abstract Underwater acoustic (UWA) channels are one of the historical mobile ultrawideband channels characterized by large delay and Doppler spreads, but reliable UWA communication remains challenging. Here we performed an initial demonstration of the Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) technique in an actual sea environment. D-OSDM spreads data symbols in both time and frequency with guardbands to exploit the time and frequency diversity of UWA channels. The experiment was performed in a challenging scenario: the transmitter was fixed on a floating pier, and the receiver was mounted on a moving remote-controlled boat. The harbor UWA channel had a delay spread of 50 ms and a Doppler spread of up to 4.5 Hz, in the presence of additive Gaussian noise, and the combination of two Rayleigh fading models (a two-path model without Doppler spread and a multi-path model with Doppler spread) was able to successfully model the actual environment. Our results also confirmed that a UWA communication link using D-OSDM will deliver excellent reliability even for a harbor UWA channel with a mobile receiver; D-OSDM achieves better communication quality compared to other communication schemes in both simulations and experiments.
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underwater acoustic communication using doppler resilient Orthogonal Signal division multiplexing with time diversity
OCEANS 2017 - Aberdeen, 2017Co-Authors: Tadashi Ebihara, Hanako OgasawaraAbstract:Recent advancements in underwater technology have made cooperative exploration, an efficient underwater exploration technique, possible. This technique networks mobile and fixed platforms, sensors and systems, and makes it possible to accomplish underwater tasks efficiently by integrated operations over a wide area and balancing exploration and exploitation. As a networking technique, underwater acoustic (UWA) communication is a technology of choice today, since it can enables mobility and flexibility in cooperative exploration systems. However, UWA communication still has several design challenges which need to be carefully addressed. To provide a reliable UWA modem suitable for cooperative exploration, in this study we designed a Doppler-resilient Orthogonal Signal division multiplexing with time diversity (D-OSDM-TD) and evaluated its performance in simulations and experiments. We evaluated the D-OSDM-TD in simulations and experiments and found that the D-OSDM-TD achieved a far better bit-error-rate performance in UWA channels with delay and Doppler spreads using low Signal power and without using a receiver array. We expect that D-OSDM-TD can become a viable alternative offering highly reliable communication for underwater operations, and we believe it is suitable for underwater cooperative operations.
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harbor trial of underwater acoustic communication using doppler resilient Orthogonal Signal division multiplexing
Journal of the Acoustical Society of America, 2016Co-Authors: Tadashi Ebihara, Geert Leus, Hanako OgasawaraAbstract:Underwater acoustic channels are characterized by a severe spread in time and frequency. To provide a highly reliable communication environment in doubly spread channels for UWA communication, we have proposed Doppler-resilient Orthogonal Signal-division multiplexing (D-OSDM). D-OSDM is a combination of the OSDM technique and Orthogonal multiple access, and it preserves Orthogonality among data streams even after propagation through doubly spread channels. We have conducted test tank experiments and simulations, and have found that D-OSDM could cope well with time- and frequency-spread channels and that it achieves a good communication quality [1]. In this talk, we will show some results of our first sea trial of D-OSDM, that was performed on 21 June, 2016 at Hashirimizu port, Kanagawa, Japan. In this trial, the transmitter is fixed on the harbor quay, and the receiver is fixed on a remotely-operated survey boat. Acoustic communication was performed by moving the boat to generate a severe spread in freque...
Jing Han - One of the best experts on this subject based on the ideXlab platform.
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equalization of osdm over time varying channels based on diagonal block banded matrix enhancement
Signal Processing, 2020Co-Authors: Jing Han, Yujie Wang, Zehui Gong, Geert LeusAbstract:Abstract Orthogonal Signal-division multiplexing (OSDM) has recently emerged as a promising alternative to Orthogonal frequency division multiplexing (OFDM) for high-rate wireless communications. Although providing more flexibility in system design, it suffers from a special interference structure, namely inter-vector interference (IVI), when channel time variations are present. In this paper, we first derive the general OSDM Signal model over time-varying channels, and then show that a time-domain window can be used to enhance the diagonal-block-banded (DBB) approximation of the channel matrix in a transformed domain. Furthermore, based on the DBB matrix enhancement, a low-complexity OSDM equalization algorithm is designed. Simulation results indicate that the proposed equalizer has significant performance advantages over that using the direct DBB approximation.
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low complexity equalization of Orthogonal Signal division multiplexing in doubly selective channels
IEEE Transactions on Signal Processing, 2019Co-Authors: Jing Han, Lingling Zhang, Qunfei Zhang, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a generalized modulation scheme to bridge the gap between Orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. It allows significantly more flexibility in system design; however, over doubly-selective channels, it suffers from a special Signal distortion structure, namely inter-vector interference, which is analogous to inter-carrier interference in conventional OFDM. To analyze its effect, in this paper, the complex exponential basis expansion model (CE-BEM) is used to approximate the doubly-selective channel. We show that the composite channel matrix of OSDM systems is cyclically block banded in this case, and the blocks in its main band can be further diagonalized. By exploiting this unique matrix structure, low-complexity block and serial OSDM equalization algorithms are then proposed. These two equalization algorithms are based on block LDL $^H$ factorization and block iterative matrix inversion, respectively, both of which are implemented in a transformed domain to avoid direct inversion of large matrices. In addition, a CE-BEM channel estimation method is designed for OSDM systems, which uses frequency-shifted Chu sequences as pilots to ease the computation. Numerical simulations are finally provided to justify the validity of our channel equalization and estimation algorithms.
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time domain oversampled Orthogonal Signal division multiplexing underwater acoustic communications
Journal of the Acoustical Society of America, 2019Co-Authors: Jing Han, Yujie Wang, Lingling Zhang, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a recently emerging modulation scheme which, compared to conventional Orthogonal frequency-division multiplexing, can effectively lower the peak-to-average power ratio and introduce intra-vector frequency diversity. In this paper, a time-domain oversampled OSDM system for underwater acoustic (UWA) communications is designed, where each OSDM vector is equivalently transmitted over multiple virtual channels, and thus an enhanced frequency diversity gain can be achieved. Moreover, at the receiver, zero vectors and frequency-shifted Chu sequences are used for Doppler compensation and channel estimation, respectively, while low-complexity per-vector equalization is performed based on the composite channel matrix factorization. Finally, the performance of the proposed OSDM system is evaluated through both numerical simulations and a short-range field experiment, and its effectiveness over time-varying UWA channels is confirmed.
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iterative per vector equalization for Orthogonal Signal division multiplexing over time varying underwater acoustic channels
IEEE Journal of Oceanic Engineering, 2019Co-Authors: Jing Han, Qunfei Zhang, Sundeep Prabhakar Chepuri, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a promising modulation scheme that provides a generalized framework to unify Orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. By partitioning each data block into vectors, it allows for a flexible configuration to trade off resource management flexibility with peak-to-average power ratio. In this paper, an OSDM system is proposed for underwater acoustic communications. The channel Doppler effect after front-end resampling is modeled as a common time-varying phase on all propagation paths. It leads to a special Signal distortion structure in the OSDM system, namely, intervector interference, which is analogous to the intercarrier interference in the conventional OFDM system. To counteract the related performance degradation, the OSDM receiver performs iterative detection, integrating joint channel impulse response and phase estimation, equalization, and decoding in a loop. Meanwhile, to avoid inversion of large matrices in channel equalization, frequency-domain per-vector equalization is designed, which can significantly reduce the computational complexity. Furthermore, the performance of the proposed OSDM system is evaluated through both numerical simulations and a field experiment, and its reliability over underwater acoustic channels is confirmed.
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space frequency coded Orthogonal Signal division multiplexing over underwater acoustic channels
Journal of the Acoustical Society of America, 2017Co-Authors: Jing Han, Wentao Shi, Geert LeusAbstract:Orthogonal Signal-division multiplexing (OSDM) is a newly emerged modulation scheme which provides a generalized framework unifying conventional Orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency domain equalization. In this letter, a space-frequency block coding (SFBC) scheme based on OSDM is proposed for time-varying underwater acoustic channels. The receiver processing includes Doppler compensation, channel estimation, space-frequency decoding, and equalization. Simulation and experimental results demonstrate its superiority over the existing SFBC-OFDM counterpart.
Hanako Ogasawara - One of the best experts on this subject based on the ideXlab platform.
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underwater acoustic communication using multiple input multiple output doppler resilient Orthogonal Signal division multiplexing
IEEE Journal of Oceanic Engineering, 2020Co-Authors: Tadashi Ebihara, Hanako Ogasawara, Geert LeusAbstract:In this paper, we propose a novel underwater acoustic (UWA) communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) and multiple-input–multiple-output (MIMO) Signaling. We present both the transmitter processing and the receiver processing for MIMO D-OSDM. We evaluate the performance of MIMO D-OSDM in simulations with a large intersymbol interference of 25 symbols and a Doppler spread with a maximum Doppler shift of 8 Hz. In addition, the sea trial is performed in Suruga Bay, where the receiver is mounted on a barge and a research vessel with the transmitter makes round trips along a line with a speed of 4 kn. In the experiments, we obtain an intersymbol interference of 3.6–29.7 symbols and a Doppler spread of several Hertz (leading to a spread of over two to three subcarrier spacings). The simulation results suggest that MIMO D-OSDM has an advantage over normal D-OSDM, Doppler-resilient MIMO Orthogonal frequency division multiplexing (MIMO D-OFDM), and classical OFDM with MIMO Signaling (MIMO OFDM)—MIMO D-OSDM achieves better bit error rate performance than the benchmarks. The sea trial results also support the advantage of MIMO D-OSDM—it achieves a coded block error rate of 3.2% while normal D-OSDM and MIMO D-OFDM achieve a coded block error rate of 9.7% and 9.3%, respectively. We conclude that MIMO D-OSDM can become a viable technique that achieves reliable and effective UWA communication.
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underwater acoustic communication using multiple input multiple output doppler resilient Orthogonal Signal division multiplexing
OCEANS Conference, 2018Co-Authors: Tadashi Ebihara, Geert Leus, Hanako OgasawaraAbstract:In this paper, we propose a novel underwater acoustic communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) and multiple-input multiple-output (MIMO) Signaling. We present both the transmitter and receiver processing for MIMO D-OSDM. We evaluate the performance of MIMO D-OSDM in simulations with a large inter-symbol interference (60 symbols) and Doppler spread (maximum Doppler shift of 15 Hz). The simulation results show that MIMO D-OSDM achieves almost the same energy efficiency as normal D-OSDM while doubling the spectrum efficiency. We conclude that MIMO D-OSDM can become a viable technique that achieves reliable and effective UWA communication.
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underwater acoustic communication using doppler resilient Orthogonal Signal division multiplexing in a harbor environment
Physical Communication, 2018Co-Authors: Tadashi Ebihara, Geert Leus, Hanako OgasawaraAbstract:Abstract Underwater acoustic (UWA) channels are one of the historical mobile ultrawideband channels characterized by large delay and Doppler spreads, but reliable UWA communication remains challenging. Here we performed an initial demonstration of the Doppler-resilient Orthogonal Signal division multiplexing (D-OSDM) technique in an actual sea environment. D-OSDM spreads data symbols in both time and frequency with guardbands to exploit the time and frequency diversity of UWA channels. The experiment was performed in a challenging scenario: the transmitter was fixed on a floating pier, and the receiver was mounted on a moving remote-controlled boat. The harbor UWA channel had a delay spread of 50 ms and a Doppler spread of up to 4.5 Hz, in the presence of additive Gaussian noise, and the combination of two Rayleigh fading models (a two-path model without Doppler spread and a multi-path model with Doppler spread) was able to successfully model the actual environment. Our results also confirmed that a UWA communication link using D-OSDM will deliver excellent reliability even for a harbor UWA channel with a mobile receiver; D-OSDM achieves better communication quality compared to other communication schemes in both simulations and experiments.
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underwater acoustic communication using doppler resilient Orthogonal Signal division multiplexing with time diversity
OCEANS 2017 - Aberdeen, 2017Co-Authors: Tadashi Ebihara, Hanako OgasawaraAbstract:Recent advancements in underwater technology have made cooperative exploration, an efficient underwater exploration technique, possible. This technique networks mobile and fixed platforms, sensors and systems, and makes it possible to accomplish underwater tasks efficiently by integrated operations over a wide area and balancing exploration and exploitation. As a networking technique, underwater acoustic (UWA) communication is a technology of choice today, since it can enables mobility and flexibility in cooperative exploration systems. However, UWA communication still has several design challenges which need to be carefully addressed. To provide a reliable UWA modem suitable for cooperative exploration, in this study we designed a Doppler-resilient Orthogonal Signal division multiplexing with time diversity (D-OSDM-TD) and evaluated its performance in simulations and experiments. We evaluated the D-OSDM-TD in simulations and experiments and found that the D-OSDM-TD achieved a far better bit-error-rate performance in UWA channels with delay and Doppler spreads using low Signal power and without using a receiver array. We expect that D-OSDM-TD can become a viable alternative offering highly reliable communication for underwater operations, and we believe it is suitable for underwater cooperative operations.
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harbor trial of underwater acoustic communication using doppler resilient Orthogonal Signal division multiplexing
Journal of the Acoustical Society of America, 2016Co-Authors: Tadashi Ebihara, Geert Leus, Hanako OgasawaraAbstract:Underwater acoustic channels are characterized by a severe spread in time and frequency. To provide a highly reliable communication environment in doubly spread channels for UWA communication, we have proposed Doppler-resilient Orthogonal Signal-division multiplexing (D-OSDM). D-OSDM is a combination of the OSDM technique and Orthogonal multiple access, and it preserves Orthogonality among data streams even after propagation through doubly spread channels. We have conducted test tank experiments and simulations, and have found that D-OSDM could cope well with time- and frequency-spread channels and that it achieves a good communication quality [1]. In this talk, we will show some results of our first sea trial of D-OSDM, that was performed on 21 June, 2016 at Hashirimizu port, Kanagawa, Japan. In this trial, the transmitter is fixed on the harbor quay, and the receiver is fixed on a remotely-operated survey boat. Acoustic communication was performed by moving the boat to generate a severe spread in freque...
