only at lower levels and hard-decision decoding is applied at higher levels. 5.10.4多层码的代译码 v) u →Demulti Encoder for Interleaver Mapping plexer 2-ary Figure5.108 Encoder Decoder for C 0 Decoder for C m. W (a)迭代多级译码器 y Demapper for C元 计算外信息 L.(c) (b)第1级分量译码器结构 Figure5.10.9MLC的迭代译码 19 only at lower levels and hard-decision decoding is applied at higher levels. 5.10.4 多层码的迭代译码 Demulti￾plexer Encoder for Encoder for Encoder for Mapping -ary signal constellation 2A Interleaver Interleaver # # u (0) u (1) u ( 1) − u A (0) c (1) c ( 1) − c A (1) v ( 1) − v A x C0 C1 Cl−1 π1 π l−1 (0) v Figure 5.10.8 Encoder W0 W1 # # y C0 (0) cˆ (1) cˆ ( 1) cˆ " A− C1 Cl−1 Wl−2 Wl−1 （a）迭代多级译码器 y Demapper for Ci λi DEC-i 判决 1 πi − πi ( ) ˆ i c Wi W W 0 1 ~ i− W W i l + − 1 1 ~ ( ) ( ) i L c ( ) ( ) i Le 计算外信息 c （b） 第 i 级分量译码器结构 Figure 5.10.9 MLC 的迭代译码