Adaptive Equalizer Based on Second-Order Cone Programming in Underwater Acoustic Communication

An improved adaptive equalizer based on the principle of minimum mean square error (MMSE) is proposed. This optimization problem which is shown to be convex, is transformed to second-order cone (SOC) and solved using the interior point method instead of conventional iterative methods such as least mean squares (LMS) or recursive least squares (RLS). To validate its performance a single-carrier system for underwater acoustic communication with digital phase-locked loop and the adaptive fractional spaced equalizers was designed and a lake trial was carried out. According to the results, comparing with traditional equalizers based on LMS and RLS algorithms, the equalizer proposed needs no iterative process and gets rid of the contradiction between convergent rate and precision. Therefore it overcomes the difficulty of parameters setting. Furthermore, the algorithm needs much less training codes to achieve the same equalization performance and improves the communication efficiency. Copyright © 2014 IFSA Publishing, S. L.