Abstract
In this paper, we introduce carrier interferometry OFDM (CI/OFDM) into the underwater acoustic transmission field, and put the emphasis on how to deal with BER during communication with LDPC approach. We also analyze the error distribution of the received CI/OFDM signal, and propose a kind of CI-OFDM-LDPC joint algorithm to solve this problem. The result shows that even if the BER reaches a level of 10-2, it can be corrected completely in this way.