Doppler Compensation Algorithm Using Coded Estimation BER in Underwater Acoustic Communication

Abstract

The underwater wireless acoustic communication channel is a time-varying channel which has a rapidly changing channel transfer characteristic. Especially, Doppler shift, occurred by currents and wind, possibly affect to the performance of the communication system. To overcome such degradation factor of underwater communication channel, we proposed an algorithm to compensate Doppler shift on data by using coded estimation BER technique, which can achieve estimated BER of coded data by comparing received data and decoded data. A sea experiment conducted to analyze the efficiency of proposed Doppler compensation algorithm using coded estimation BER in the underwater communication by using turbo codes with a coding rate of 1/3. Experimental results showed that coded estimation BER has the lowest value at the point of exact Doppler offset. Also, through the five trials of sea experiment, only one trial was succeeded with the conventional method. However, with the proposed method, all five trials were succeeded. Therefore, we confirm that proposed algorithm is well operated in the environment of time varying underwater communication channel.