Abstract
This paper discusses channel sounders for underwater acoustic communications (UWAC), which estimate channel impulse response (CIR) using commercial electronic acoustic devices and off-line signal processing. Although transmission channel models are inevitable in performance evaluation of wireless communications, there are a few reports on channel models for UWAC. In order to obtain channel models for UWAC, channel sounders play important roles. Thus, if channel sounders can be realized by commercial electronic acoustic devices, it is easy to sound CIR in UWAC channel environment. The proposed simple acoustic channel sounders can suppress frequency distortion and frequency deviation due to mismatch between a transmitter and a receiver of commercial electronic acoustic devices. Furthermore, the channel sounder can precisely detect time-varying CIR by means of cyclic correlation. Finally, this paper evaluates performance of the proposed channel sounders in actual shallow UWAC environment in Lake Biwa.
