Low-Cost Blind and Semi-Blind Equalizers for Nonlinear SIMO Systems

Nonlinearities in systems, such as those encountered in optical and satellite communications, can significantly degrade signal quality and require advanced equalization techniques for effective compensation. This work introduces an innovative blind and semi-blind (SB) signal estimation method designed for Single-Input Multiple-Output (SIMO) systems with nonlinearity. The proposed approach leverages the truncated covariance matrix kernel in conjunction with signal subspace properties and pilot symbols (when available) to compute an accurate equalizer. Furthermore, a low-complexity variant of the equalizer, which bypasses subspace decomposition, is presented. Extensive simulations are conducted to evaluate the performance of the proposed equalizers in nonlinear multichannel systems. The results demonstrate the effectiveness of the proposed methods, achieving robust signal estimation with significantly reduced computational overhead, making them suitable for practical deployment in resource-constrained environments.