Figure 4.

The procedure of STBP and ITBP. For STBP, the operated sequence {ô₇, ô₆, ⋯ , ô₀} (we denote the sequence as ${\widehat{\text{o}}}_{Seq}$) is transformed into ŷ via UWD. Then MSE between y and ŷ is calculated. For ITBP, y is transformed into input sequence {o₇, o₆, ⋯ , o₀} (we denote the sequence as o_Seq) by UWE. Then, calculate weighted MSE between ${\widehat{\text{o}}}_{Seq}$ and o_Seq by Equation (11), where ${\widehat{\text{o}}}_{Seq}$ is the operated sequence ready to be decoded.