Time Reversal Acoustic Communication Using Filtered Multitone Modulation

Lin Sun; Baowei Chen; Haisen Li; Tian Zhou; Ruo Li

doi:10.3390/s150923554

Time Reversal Acoustic Communication Using Filtered Multitone Modulation

Sensors (Basel). 2015 Sep 17;15(9):23554-71. doi: 10.3390/s150923554.

Authors

Lin Sun^{1

2}, Baowei Chen^{3

4}, Haisen Li^{5

6}, Tian Zhou^{7

8}, Ruo Li^{9

10}

Affiliations

¹ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. zcbsunny@hrbeu.edu.cn.
² Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China. zcbsunny@hrbeu.edu.cn.
³ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. chenbaowei@hrbeu.edu.cn.
⁴ Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China. chenbaowei@hrbeu.edu.cn.
⁵ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. hsli@hrbeu.edu.cn.
⁶ Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China. hsli@hrbeu.edu.cn.
⁷ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. zhoutian@hrbeu.edu.cn.
⁸ Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China. zhoutian@hrbeu.edu.cn.
⁹ College of Underwater Acoustic Engineering, Harbin Engineering University, Harbin 150001, China. liruo@hrbeu.edu.cn.
¹⁰ Science and Technology on Underwater Acoustic Laboratory, Harbin Engineering University, Harbin 150001, China. liruo@hrbeu.edu.cn.

Abstract

The multipath spread in underwater acoustic channels is severe and, therefore, when the symbol rate of the time reversal (TR) acoustic communication using single-carrier (SC) modulation is high, the large intersymbol interference (ISI) span caused by multipath reduces the performance of the TR process and needs to be removed using the long adaptive equalizer as the post-processor. In this paper, a TR acoustic communication method using filtered multitone (FMT) modulation is proposed in order to reduce the residual ISI in the processed signal using TR. In the proposed method, FMT modulation is exploited to modulate information symbols onto separate subcarriers with high spectral containment and TR technique, as well as adaptive equalization is adopted at the receiver to suppress ISI and noise. The performance of the proposed method is assessed through simulation and real data from a trial in an experimental pool. The proposed method was compared with the TR acoustic communication using SC modulation with the same spectral efficiency. Results demonstrate that the proposed method can improve the performance of the TR process and reduce the computational complexity of adaptive equalization for post-process.

Keywords: adaptive equalization; filtered multitone modulation; time reversal; underwater acoustic communication.