Qin Zhen, Tao Jun, Qu Fengzhong, Qiao Yongjie
Key Laboratory of Underwater Acoustic Signal Processing of the Ministry of Education, School of Information Science and Engineering, Southeast University, Nanjing 210096, China.
Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Zhejiang University, Zhoushan, 316021, China.
J Acoust Soc Am. 2022 May;151(5):2877. doi: 10.1121/10.0010370.
The sparse property of a direct adaptive equalizer (DAE) for single-carrier underwater acoustic communications is well recognized. It has been used to improve the performance and/or reduce the complexity of a DAE. Extensive investigations have been performed in terms of performance improvement. On the contrary, research on complexity reduction remains preliminary. A fundamental way for reducing the complexity of a DAE is to keep only significant taps while discarding trivial taps, that is, to run a partial-tap DAE. Existing partial-tap DAE designs assume a slowly varying sparse structure and may suffer performance degradation under a severe underwater environment. Motivated by this fact, the dynamic compressed sensing (DCS) technique is resorted to and a partial-tap DAE based on the sparse adaptive orthogonal matching pursuit-affine projection algorithm is proposed. The sparse adaptive orthogonal matching pursuit-affine projection algorithm-direct adaptive equalizer (SpAdOMP-APA-DAE) achieves symbol-wise updating of both positions and values of the significant coefficients. In this paper, a more extensive study on DCS-based DAEs is performed, and an enhanced dynamic compressed sensing-direct adaptive equalizer design enabled by the sparse adaptive subspace pursuit-improved proportionate affine projection algorithm (SpAdOMP-IPAPA) is proposed. The sparse adaptive subspace pursuit-improved proportionate affine projection algorithm-direct adaptive equalizer enjoys lower complexity while better performance than the previous SpAdOMP-APA-DAE. Experimental results corroborated the superiority of the SpAdOMP-IPAPA-DAE.
单载波水声通信中直接自适应均衡器（DAE）的稀疏特性已得到广泛认可。它已被用于提高DAE的性能和/或降低其复杂度。在性能提升方面已经进行了广泛的研究。相反，关于复杂度降低的研究仍处于初步阶段。降低DAE复杂度的一种基本方法是只保留有效抽头而舍弃无关抽头，即运行部分抽头DAE。现有的部分抽头DAE设计假定稀疏结构变化缓慢，在恶劣的水下环境中可能会导致性能下降。受这一事实的启发，采用了动态压缩感知（DCS）技术，并提出了一种基于稀疏自适应正交匹配追踪 - 仿射投影算法的部分抽头DAE。稀疏自适应正交匹配追踪 - 仿射投影算法直接自适应均衡器（SpAdOMP - APA - DAE）实现了对有效系数的位置和值进行符号级更新。本文对基于DCS的DAE进行了更广泛的研究，并提出了一种由稀疏自适应子空间追踪 - 改进的比例仿射投影算法（SpAdOMP - IPAPA）实现的增强型动态压缩感知 - 直接自适应均衡器设计。与之前的SpAdOMP - APA - DAE相比，稀疏自适应子空间追踪 - 改进的比例仿射投影算法直接自适应均衡器具有更低的复杂度和更好的性能。实验结果证实了SpAdOMP - IPAPA - DAE的优越性。
