Low Complexity Adaptive Equalizers for Underwater Acoustic Communications

• Published in: China ocean engineering 2014-08, Vol.28 (4), p.529-540
• Main Authors: Soflaei, Masoumeh, Azmi, Paeiz
• Format: Article
• Language: English
• Subjects: Coastal Sciences; Engineering; Fluid- and Aerodynamics; Marine & Freshwater Sciences; NLMS算法; Numerical and Computational Physics; Oceanography; Offshore Engineering; Simulation; 仿射投影算法; 低复杂度; 失调误差; 收敛速度; 水声通信; 自适应均衡器; 自适应算法
• ISSN: 0890-5487; 2191-8945
• DOI: 10.1007/s13344-014-0043-2

Interference signals due to scattering from surface and reflecting from bottom is one of the most important problems of reliable communications in shallow water channels. To solve this problem, one of the best suggested ways is to use adaptive equalizers. Convergence rate and misadjustment error in adaptive algorithms play important roles in adaptive equalizer performance. In this paper, affine projection algorithm （APA）, selective regressor APA（SR-APA）, family of selective partial update （SPU） algorithms, family of set-membership （SM） algorithms and selective partial update selective regressor APA （SPU-SR-APA） are compared with conventional algorithms such as the least mean square （LMS） in underwater acoustic communications. We apply experimental data from the Strait of Hormuz for demonstrating the efficiency of the proposed methods over shallow water channel. We observe that the values of the steady-state mean square error （MSE） of SR-APA, SPU-APA0 SPU-normalized least mean square （SPU-NLMS）, SPU-SR-APA0 SM-APA and SM-NLMS algorithms decrease in comparison with the LMS algorithm. Also these algorithms have better convergence rates than LMS type algorithm.