Orthogonal Chirp Division Multiplexing for Underwater Acoustic Communication

Bai, Yiqi; Bouvet, Pierre-Jean

doi:10.3390/s18113815

Cited by 26 publications

(16 citation statements)

References 18 publications

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“…Needless to say, identifying which signal comes from which source is the main concern here. A more detailed investigation should reveal which multiple access protocol is suited to address this challenge and existing chirp based techniques [21][22][23] should be tested. The robustness against Doppler shifts of the acoustic chirps [43] needs to be verified and tracking algorithms to counter the potentially introduced error can be investigated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes

Cox

Perre

Wielandt

et al. 2020

J Wireless Com Network

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Hybrid acoustic-RF systems offer excellent ranging accuracy, yet they typically come at a power consumption that is too high to meet the energy constraints of mobile IoT nodes. We combine pulse compression and synchronized wake-ups to achieve a ranging solution that limits the active time of the nodes to 1 ms. Hence, an ultra low-power consumption of 9.015 µW for a single measurement is achieved. The operation time is estimated on 8.5 years on a CR2032 coin cell battery at a 1 Hz update rate, which is over 250 times larger than state-of-the-art RF-based positioning systems. Measurements based on a proof-of-concept hardware platform show median distance error values below 10 cm. Both simulations and measurements demonstrate that the accuracy is reduced at low signal-to-noise ratios and when reflections occur. We introduce three methods that enhance the distance measurements at a low extra processing power cost. Hence, we validate in realistic environments that the centimeter accuracy can be obtained within the energy budget of mobile devices and IoT nodes. The proposed hybrid signal ranging system can be extended to perform accurate, low-power indoor positioning.

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Section: Discussionmentioning

confidence: 99%

“…Autocorrelation is used to perform fast distance calculations using small data sets, as described in [18,42], and exploited in [19,20]. A linear chirp [21][22][23] is used as audio broadcast signal for two reasons. First of all, mobile nodes with different distances to the beacon, will measure other parts of the chirp signal.…”

Section: Pulse Compressionmentioning

confidence: 99%

High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes

Cox

Perre

Wielandt

et al. 2020

J Wireless Com Network

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“…The LFM has received recent interest to implement reliable underwater acoustic communication links. 30,31 Also, a digital amplifier controls the amplitude of the signal produced by the digital processor, and the gain of the amplifier can be reconfigured by the user. The control unit can also be configured to concatenate different sequences of waveforms that are optionally separated by guard intervals.…”

Section: A Software-defined Transmittermentioning

confidence: 99%

A Janus compatible software-defined underwater acoustic multiple-input multiple-output modem

Singh

Crispo

Bousquet

et al. 2021

International Journal of Distributed Sensor Networks

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This article describes the implementation of a multiple-input multiple-output acoustic communication link in shallow water conditions to enable a software-defined acoustic modem with a maximum transmission rate of 20 kbps in a 5-kHz bandwidth. The reliability improvement of a low-complexity Alamouti space–time block code is evaluated to improve the diversity in a high-rate transmission mode using single carrier modulation, as well as in a low-rate transmission mode relying on continuous-phase frequency-shift keying. Using measurements in realistic subsea conditions, the effect of the spatial channel correlation is demonstrated. It is found that for the space–time block code/continuous-phase frequency-shift keying, the spatial diversity is significantly degraded due to the high spatial correlation. In contrast, for the high-mode transmission rate, space–time block code with single carrier modulation offers a bit error rate improvement by a factor over hundred, in comparison to a single transmit element, demonstrating that the multiple-input multiple-output optimal code depends on the software-defined acoustic modem transmission mode.

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“…In (14), w is the Gaussian noise component with a mean of 0, and the variances of w and x are σ 2 w and σ 2 x , respectively. In (15), H k is the channel frequency response (CFR) of the channel at the kth frequency bin.…”

Section: B Anti-multipath Ocdm Schemementioning

confidence: 99%

“…Therefore, OCDM maximizes spectral efficiency while maintaining the robustness of CSS technology [13]. An underloaded OCDM scheme is proposed and leads to signal-to-noise ratio (SNR) gain but at the expense of the decreasing data rate [14]. Compared with the traditional OFDM system, the OCDM system offers better anti-interference ability while maintaining the same spectral efficiency [15].…”

Section: Introductionmentioning

confidence: 99%

Anti-Multipath Orthogonal Chirp Division Multiplexing for Underwater Acoustic Communication

Zhu

et al. 2020

IEEE Access

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Multipath due to reflections of the sea surface, seabed, and obstacles, as well as inhomogeneity within the ocean, is an important characteristic of underwater acoustic channels. Mutual interference among multiple paths causes severe amplitude fading and frequency selective fading. The guard interval is an effective anti-multipath method, but an excessively long guard interval will reduce the data rate of multicarrier underwater acoustic communication. In this paper, we propose a new anti-multipath multi-carrier communication method based on orthogonal chirp division multiplexing (OCDM) that uses chirp signals for carrier modulation. As OCDM exploits the multipath components for diversity gain, the system robustness is improved. The new method also adds a data pick-based rake receiver for maintaining good communication performance, even at short guard intervals. We detail the implementation and parameter selection of the antimultipath OCDM system and compare its performance with the traditional orthogonal frequency division multiplexing (OFDM) scheme using simulations; under a severe multipath simulation condition (the delay spread is longer than the guard interval), the anti-multipath OCDM achieves a bit error rate (BER) of 10 −6 , while the OFDM has a BER floor of 10 −3. The simulation results verify the feasibility of the proposed method and the superiority of its anti-multipath performance. INDEX TERMS Multipath channels, orthogonal chirp division multiplexing, underwater acoustic communication.

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Orthogonal Chirp Division Multiplexing for Underwater Acoustic Communication

Cited by 26 publications

References 18 publications

High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes

High precision hybrid RF and ultrasonic chirp-based ranging for low-power IoT nodes

A Janus compatible software-defined underwater acoustic multiple-input multiple-output modem

Anti-Multipath Orthogonal Chirp Division Multiplexing for Underwater Acoustic Communication

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