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1. Doppler Estimation Based on Frequency Average and Remodulation for Underwater Acoustic Communication.

Author

Hwang, Chan-Ho, Kim, Ki-Man, Chun, Seung-Yong, and Lee, Sang-Kook

Subjects
*DOPPLER effect, *ESTIMATION theory, *UNDERWATER acoustic communication, *TELECOMMUNICATION channels, *DATA transmission systems, *COMPUTER simulation, *BIT error rate
Abstract

Underwater acoustic communication channel is time varying and has Doppler effect due to wind, sea surface roughness, and platform motion. We have to recognize the changing channel state and apply it to communication technique for increasing transmission efficiency in the underwater acoustic channel. In this paper, we propose more reliable Doppler estimation method based on frequency average and remodulation. We conducted the simulation and sea trial to evaluate the performance of the proposed method. When the channel coding technique was not applied, the uncoded bit error rate performance of the proposed method was improved about maximum 50.3% compared with conventional method. [ABSTRACT FROM AUTHOR]

Published
2015
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2. Optimal linear estimation with square-based sampling.

Author

Zhou, Haomiao, Deng, Zhihong, Xia, Yuanqing, and Fu, Mengyin

Subjects
*SAMPLING (Process), *DATA transmission systems, *KALMAN filtering, *COMPUTER simulation, *DATA reduction, *ESTIMATION theory
Abstract

This paper is concerned with the problem of event-based sampling for the purpose of reducing the number of data transferred in control systems and the corresponding modified Kalman filter. A mathematical description based upon square-based sampling is proposed, in which the sampling occured when the accumulated difference between two adjacent sampling points satisfies the specified event condition. Then, by utilizing the square based sampling method, a modified Kalman filter algorithm is adopted, in which the measurement is sent when the output exceeds a given event. The simulation results illustrate the advantage of the new event-based sampling scheme and the effectiveness of modified Kalman filter. [ABSTRACT FROM AUTHOR]

Published
2015
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