The rapid evolution of high-speed communication technologies has brought serious inter-symbol interference (ISI). To cope with this issue, channel equalization techniques, such as feedforward equalization (FFE) and decision feedback equalization (DFE), are typically used to compensate for channel response to facilitate signal recovery, and forward error correction (FEC) code, such as low-density parity check (LDPC) codes, is widely deployed to improve link budget margin. However, the mutual influence between the equalizer and the decoder has yet to be thoroughly explored. In this paper, the state error decoding (SED) algorithm is proposed to enhance the decoding performance by effectively reducing the error probabilities and surpassing the limitations of traditional signal recovery methods. Experimental results in a photonic terahertz wireless communication system achieve error propagation mitigation and additional 0.2 dB link budget improvement by utilizing the proposed SED method, which confirms the effectiveness of the algorithm in reducing error propagation and improving system performance, paving the way for the development of broadband communications.