Abstract: The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as “Pattern Time Delay Shift Coding (PDS) communication system”.The aim of the PDS is to improve the quality of communication in shallow water. The open water experiments show that at the condition of 2 kHz bandwidth, the communication rate is more than 300 bit/s and error rate is at the level of 10^-4. The details of PDS technique will be shown, including: principle of PDS coding, the model of communication, time delay estimation, simulation of PDS communication, Anti-multipath interference and open water experiments.