As the optical communication technology advances, vortex beam with orbital angular momentum (OAM) has gained wide attention due to its potential to significantly increase the channel capacity. Under the influence of atmospheric turbulence, there are still challenging problems in the OAM multiplexing system. To the best of our knowledge, in this paper one multiple-input-multiple-output (MIMO) detection technology named K-best detection, is first applied to the OAM multiplexing system. Numerical simulation results indicate the proposed solution enhances the performance of the optical communication system compared with data-aided least mean square (DA-LMS) and minimum mean squared error (MMSE) detection. Furthermore, with MMSE sorted QR decomposition (MMSE-SQRD) preprocessing, the performance of K-best detection can be further improved. When C ²_n = 1×10⁻¹⁴, about 4.4 dB signal-to-noise ratio (SNR) gain can be obtained by preprocessing at k = 2 while the complexity is not significantly increased. Computational complexity is also analyzed in this paper, results show that K-best detection with winner path extension (WPE) algorithm can achieve 43% system complexity reduction, achieving a compromise between performance and complexity in K-best detection.

随着光通信技术的进步，具有轨道角动量（OAM）的涡旋光束因其显着增加信道容量的潜力而受到广泛关注。在大气湍流的影响下，OAM复用系统仍然存在具有挑战性的问题。据我们所知，在本文中，一种名为 K-best 检测的多输入多输出 (MIMO) 检测技术首次应用于 OAM 复用系统。数值仿真结果表明，与数据辅助最小均方 (DA-LMS) 和最小均方误差 (MMSE) 检测相比，所提出的解决方案提高了光通信系统的性能。此外，通过MMSE排序的QR分解（MMSE-SQRD）预处理，可以进一步提高K-best检测的性能。当 C ² _n = 1×10 ^-14，通过k = 2的预处理可以获得大约4.4dB的信噪比(SNR)增益，而复杂度没有显着增加。本文还对计算复杂度进行了分析，结果表明，采用获胜者路径扩展（WPE）算法的 K-best 检测可以实现 43% 的系统复杂度降低，在 K-best 检测中实现了性能和复杂度之间的折衷。