In this paper, the performance of adaptive turbo equalization for nonlinearity compensation (NLC) is investigated. A turbo equalization scheme is proposed where a recursive least-squares (RLS) algorithm is used as an adaptive channel estimator to track the time-varying intersymbol interference (ISI) coefficients associated with inter-channel nonlinear interference (NLI) model. The estimated channel coefficients are used by a MIMO 2x2 soft-input soft-output (SISO) linear minimum mean square error (LMMSE) equalizer to compensate for the time-varying ISI. The SISO LMMSE equalizer and the SISO forward error correction (FEC) decoder exchange extrinsic information in every turbo iteration, allowing the receiver to improve the performance of the channel estimation and the equalization, achieving lower bit-error-rate (BER) values. The proposed scheme is investigated for polarization multiplexed 64QAM and 256QAM, although it applies to any proper modulation format. Extensive numerical results are presented. It is shown that the scheme allows up to 0.7 dB extra gain in effectively received signal-to-noise ratio (SNR) and up to 0.2 bits/symbol/pol in generalized mutual information (GMI), on top of the gain provided by single-channel digital backpropagation.

翻译：在本文中,对调适涡轮对非线性补偿的平衡性(NLLC)的绩效进行了调查,建议采用涡轮衡平准办法,即使用递归性最低平方(RLS)算法作为调适通道估计器,跟踪与气道非线性干扰(NLI)模式相关的时间变化间干扰(ISI)系数。估计的频道系数用于MIMO 2x2软投入软性软输出最小平均平差(SISO)线性平均差(LMMSE)等值,以补偿时间变化的 ISI。SISO LMMSE 等同器和SISO前方差错校正(FEC) 调差异差异差交换(FES) 在每个涡轮循环中跟踪跟踪跟踪时间变化,使接收者能够改进频道估计和平衡性,达到较低的位调率(BER)值。拟议的办法用于对极分极化后向64QAM和256QAM进行调查,尽管适用于任何适当的调制格式。 Sl-CM-C-S 双向双向双向双向双向平级平级(通过收到的双向双向数字/双向双向双向平级平方/双向平方/双向双向双向平方平方平方平方之间测测测测测测测测测测算),显示,显示双向双向双向双向双向双向双向双向平平平平平平平方平方平平平平平平平方平方平方案。