Wu Fei-Yun, Yang Hui-Zhong, Liu Shengxing
Navigation College, Jimei University, Xiamen, Fujian 361021, China.
School of Marine Science and Technology, Northwestern Polytechnical University, Xian, Shaanxi 710072, China.
J Acoust Soc Am. 2024 Oct 1;156(4):2250-2264. doi: 10.1121/10.0030406.
Recursive least squares (RLS)-based equalizers are hindered by their high complexity in underwater acoustic (UWA) communications. This article proposes an adaptive equalizer with a phase tracking method for the UWA communication, named the error-feedback lattice-equalizer (EFLE). First, we derive the algorithm for recursively solving the least squares problem from EFLE, introducing a lattice structure using time and order updates, thereby reducing the complexity to be linearly related to its length. The error-feedback mechanism used in computing reflection coefficients ensures the numerical stability of the algorithm. By focusing on the rapid tap rotation in time-varying channels, we design phase tracking in EFLE to further improve equalization performance. To verify the bit error rate (BER) performance of the proposed EFLE, we study the UWA communication system and conduct UWA simulations and at-sea experiments. Comparisons include linear complexity equalizers such as least mean square (LMS), leaky LMS, least mean mixed-norm, and ϵ-normalized LMS equalizers, and quadratic complexity RLS equalizers. At-sea experiment results show that the BER performance of EFLE significantly outperforms its counterparts.
基于递归最小二乘（RLS）的均衡器在水下声学（UWA）通信中因其高复杂度而受到阻碍。本文提出了一种用于UWA通信的具有相位跟踪方法的自适应均衡器，称为误差反馈格型均衡器（EFLE）。首先，我们从EFLE推导出递归求解最小二乘问题的算法，引入使用时间和阶数更新的格型结构，从而将复杂度降低到与其长度呈线性关系。计算反射系数时使用的误差反馈机制确保了算法的数值稳定性。通过关注时变信道中的快速抽头旋转，我们在EFLE中设计了相位跟踪以进一步提高均衡性能。为了验证所提出的EFLE的误码率（BER）性能，我们研究了UWA通信系统并进行了UWA仿真和海上实验。比较对象包括线性复杂度均衡器，如最小均方（LMS）、泄漏LMS、最小均方混合范数和ϵ归一化LMS均衡器，以及二次复杂度的RLS均衡器。海上实验结果表明，EFLE的BER性能明显优于其同类产品。
