A search algorithm for code sets of time frequency coding used in underwater acoustic communications

Time-frequency coding modulation shows strong ability against fast fading in wireless channel, study on it used in underwater acoustic communication progressed in recent years. Performances of different time-frequency codeword group vary greatly. Marine underwater acoustic channel is sparse multipath channel with random delay, this paper presents three points about time-frequency coding principle used in it, and accordingly wrote a searching program based on backtracking algorithm so as to find out code groups with different property quickly and reliably. In this article the problem of searching for eligible code groups is detailedly analysed, then searching algorithm is derived from it, finally the algorithm is realized and running flowchart is given.