An underwater acoustic 64QAM OFDM communication system with robust Doppler compensation

Wada, Tomohisa; Suzuki, Taisaku; Yamada, Hiromasa; Nakagawa, Shigeto

doi:10.1109/oceans.2016.7761056

Cited by 6 publications

(1 citation statement)

References 3 publications

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“…In such cases, the difference in time of occurrence of two chirp signals transmitted with a certain time interval is determined and from this the Doppler factor is calculated, allowing the received signal to be corrected [13]. The correction usually consists of resampling the received signal [1], [14] although there are other approaches, such as [15], where the use of RLS filtering and PLL loops has been proposed. The paper [16] uses Kalman filtering for Doppler estimation and correction.…”

Section: Volume XX 2017mentioning

confidence: 99%

Comparison of Doppler Effect Estimation Methods for MFSK Transmission in Multipath Hydroacoustic Channel

Czapiewska,

Łuksza,

Studański

et al. 2024

IEEE Access

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Underwater wireless communication remains a challenging topic, particularly for applications such as wreck penetration where multipath and Doppler effects are very intense. These effects are becoming even more difficult to mitigate for fast data transmission systems that utilize wideband signals. Due to the low propagation speed of acoustic wave in the water, there is a significant difference between the Doppler shift for lower and upper frequencies of the utilized spectrum. To address these challenges, this paper describes various methods for determining the Doppler frequency shift for MFSK signals, including crosscorrelation, double FFT, pilots, and additional Up-Down chirp signals. The reception quality of the transmitted data in a real environment was used as an evaluation criterion for each method. The tests were carried out in motion within the towing tank for different movement speeds of the transmitter relative to the receiver. The tank's limited dimensions created conditions for multipath signal propagation. Under very difficult multipath signal propagation conditions, the pilots method was found to be the most effective. It gave over two times lower BER than the well-known Up-Down chirp method.

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