In visible light communication (VLC) systems, the data transmission quality could be deteriorated by the nonlinear distortion, which stems from the inherent characteristic of light-emitting diode. In order to eliminate the influence of nonlinearity, reproducing kernel Hilbert space based post distortion technology is an effective solution. As a kind of kernel methods, extended kernel recursive least squares (EX-KRLS) has played a role in providing linear approximation ability and adapting to environment with fast speed. Due to the fact that the implementation of EX-KRLS algorithm relies on constantly growing dictionaries, it leads to high computational complexity. To solve this problem, the approximate linear dependency (ALD) and coherence sparsification criteria (CALD) are introduced in this paper, forming the EX-KRLS-ALD/CALD post-distortions. Simulation results show that compared with the original EX-KRLS, the dictionary size of EX-KRLS-ALD is reduced by 52.6 %, while the size of EX-KRLS-CALD can be reduced by about 77 %, with the same bit error rate performance. The numerical results prove that the proposed strategy meets the expectations in suppressing the dictionary size and reducing the computational costs.

中文翻译：

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用于可见光通信的基于扩展内核递归最小二乘的低复杂度后失真器

在可见光通信（VLC）系统中，由于发光二极管的固有特性，非线性失真可能会导致数据传输质量下降。为了消除非线性的影响，基于再生核希尔伯特空间的后失真技术是一种有效的解决方案。扩展核递归最小二乘法(EX-KRLS)作为一种核方法，发挥了提供线性逼近能力、快速适应环境的作用。由于EX-KRLS算法的实现依赖于不断增长的字典，导致计算复杂度较高。为了解决这个问题，本文引入了近似线性相关性（ALD）和相干稀疏化准则（CALD），形成了EX-KRLS-ALD/CALD后失真。仿真结果表明，与原始EX-KRLS相比，在相同误码率的情况下，EX-KRLS-ALD的字典大小减少了52.6%，而EX-KRLS-CALD的大小可减少约77%表现。数值结果证明所提出的策略在抑制字典大小和降低计算成本方面满足了预期。