Self-interference suppression in MIMO power line communication based on spatial linear projection filter

In modern communication technology applications, electromagnetic coupling inevitably occurs among multiple channels in multiple-input multiple-output (MIMO) power line communication (PLC) systems, which gives rise to signal crosstalk between channels and introduces additional detrimental effects on communication stability and effectiveness. This paper proposes a self-interference suppression method for MIMO-PLC. The complete implementation architecture of the MIMO-PLC system is first delineated, followed by an analysis of adaptive modulation in MIMO-PLC to ascertain the ideal signal form at the receiving end. The structure of the MIMO-OFDMA PLC system is examined under the influence of complex physical layer techniques, and a mathematical representation of carrier communication signals containing self-interference is provided. The spatial linear projection filter (SLPF) is innovatively adopted as the spatial projection filtering algorithm for self-interference suppression. Geometrically, this approach is equivalent to determining whether a point consistently lies on the same side of a convex hull formed by multiple points, thereby enabling the separation of crosstalk signals in carrier communication and achieving self-interference suppression in PLC. Experimental results demonstrate that after applying the proposed self-interference suppression method, the signal-to-noise ratios (SNRs) of segmented signals are improved to 26.32 dB and 14.88 dB, with corresponding SNR error rates of 0.73 ± 0.056% and 0.91 ± 0.062%, respectively. These results indicate that the design method enables the receiving end to recover original data more accurately, thereby enhancing the overall reliability and stability of carrier communication. The method also exhibits strong practical effectiveness in communication applications.