In this paper, the design of a Turbo equalizer is described. The equalizer is used as a part of the receiver when the QPSK modulation is used in underwater acoustic communications. The purpose of the equalizer is to remove the inter-symbol interference which is caused by the multipath propagation of the underwater acoustic signals. Anlaboratorysimulationswas conducted basedonProakis'B channel model. To verify the validity of the equalizer, a lake experiment is then carried out in June, 2015. During the experiment, QPSK signals were transmitted at the rate of 6000sps, and the range of the communication is from 700 meters to 2200 meters. The results of the experiment shows that the equalizer can effectively remove the ISI when the multipath propagation is not severe.
['Lijun Xu', 'Shefeng Yan']
Turbo Equalization Based on Single Carrier QPSK Modulation for Underwater Acoustic Channel