## 1 Introduction  
For the construction of underwater acoustic sensor networks, high data rate acoustic communications have been extensively researched to improve the throughput of sensor nodes. In order to achieve reliable performance with relatively low implementation complexity, the high data rate single-carrier (SC) acoustic communication using time reversal (TR) has been studied in recent years [1; 2; 3; 4; 5; 6; 7]. For a given underwater acoustic channel with large multipath spread, the higher symbol rate results in the larger intersymbol interference (ISI) span which reduces the performance of the TR process. The larger ISI span needs to be removed through longer adaptive equalizers in the high data rate SC acoustic communication using TR. To shorten the span of ISI in SC acoustic communication using TR, multicarrier modulation can be used in the TR acoustic communication. In multicarrier modulation for acoustic communications [8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23], researches have mainly focused on orthogonal frequency-division multiplexing (OFDM) [8; 9; 10; 11; 12; 13; 14; 15; 16; 21; 22; 23]. In OFDM, the available frequency band is divided into a number of overlapping subcarriers which have the small bandwidth to avoid ISI. However, since the subcarriers in OFDM are overlapping, the small bandwidth of each subcarrier can result in that the communication performance is sensitive to frequency offset. A slight frequency offset in OFDM can lead to severe intercarrier interference (ICI). Therefore, in order to obtain good performance, complicated algorithms at the receiver must be exploited to suppress ICI [24; 25; 26]. In order to avoid ICI, some other multicarrier modulation schemes have been studied in acoustic communications. [PERSON] _et al._[17] proposed a multicarrier modulation scheme which divided the available frequency band into two separate subcarriers with 1 kHz bandwidth, and a guard band was set between subcarriers. A similar multicarrier modulation scheme with wider subcarriers was proposed by [PERSON] _et al._[18; 19], in which the bandwidth of each subcarrier was 4.5 kHz and guard bands were also inserted between subcarriers. In the multicarrier modulation schemes respectively proposed by [PERSON] _et al._ and [PERSON] _et al._, widely separate subcarriers and guard bands can keep the acoustic communication system from ICI, but guard bands can also result in the lower spectral efficiency compared with the SC modulation using similar transmit filters with the same roll-off factor over the whole frequency band. In order to overcome the disadvantage of OFDM while keeping high spectral efficiency, [PERSON] _et al._[20] studied the acoustic communication using filtered multitone (FMT) modulation [27; 28; 29; 30; 31; 32; 33] which divided the available frequency band into several separate subcarriers without guard bands, and compared the performance of FMT acoustic communication with that of OFDM acoustic communication. In FMT, each subcarrier is separate and the bandwidth is relatively wide. Therefore, when some frequency offset occurs in FMT, ICI is relatively slight and a minor concern compared with ISI. Furthermore, compared with the multicarrier modulation schemes proposed respectively by [PERSON] _et al._ and [PERSON] _et al._, due to no guard bands, FMT has the same spectral efficiency as the SC modulation using similar transmit filters with the same roll-off factor overthe whole frequency band. FMT modulation for acoustic communications has attracted increasing interest recently [31,32]. Based on the high spectral efficiency and good ICI suppression of FMT modulation, a TR acoustic communication method using FMT modulation is proposed in this paper for the purpose of improving the performance of the TR process and reducing the computational complexity of adaptive equalization for post-process.