Fig5.10.3 2)(0) 8-ASK mapper 000001010011100101110111 Equivalent mapper 0 0 0 channel y 0:01010101 Equivalent mapper for=0 0+ 一X十0十一十 channel y :0 1 0 1 Equivalent mapper for=00 channel :0 1 Figure5.10.3 From the chain rule,the mutual information of the equivalent channel ican be calculated as Tcm;yco.c-w）=tc0c-n:yc-）-T(cewc-:yc.cm） where Y is calculated by averaging over all possible combinations ofco.c-).(在第i层的所有信号子集上求平均)。即 io.-y.）=Emz(o,yoe} Random variables Outcome 等效信道的概念是分析与设计编码调制方案的基本工具。 Thus,the capacity of the equivalent channel is given by c=(r)=E[c(([c(x(] where C)denotes the capacity when using only the subset)with a priori probabilities P(a)/P) The capacity C)将作为第i层分量码的码率设计依据。The total capacity C of a 15 15 Fig.5.10.3 . (2) (1) (0) ccc (1) (0) c c = 00 Figure 5.10.3 From the chain rule, the mutual information of the equivalent channel i can be calculated as ( ) ( ) ( ) ( ) (0) ( 1) ( ) ( 1) (0) ( 1) ( 1) ( 1) (0) ( ) ; . . ; . . ; . i i il i i l i c Yc c c c Yc c c c Yc c − − − +− II I = − where ( ) ( ) ( 1) (0) ( 1) . ; . il i c c Yc c − − I is calculated by averaging over all possible combinations of (0) ( 1) . i c c − . (在第 i 层的所有信号子集上求平均)。即 ( ) (0) ( 1) { ( )} ( ) ( 1) (0) ( 1) ( ) ( 1) (0) ( 1) . . ; . . ; . i il i il i c c c c Yc c c c Yc c − −− −− I I = E 等效信道的概念是分析与设计编码调制方案的基本工具。 Thus, the capacity of the equivalent channel is given by ( ) (0) ( 1) (0) ( ) ( ( )) ( ) ( ) ( ) ( ) (0) ( 1) (0) ( 1) (0) ( ) . . ; . . . i i ii i i i cc cc C c Yc c C c c C c c − − − == − ⎡ ⎤⎡ ⎤ ⎣ ⎦⎣ ⎦ ￾ XX E E where ( ) ( ) (0) ( ) . i C cc X denotes the capacity when using only the subset ( ) (0) ( ) . i X c c with a priori probabilities { ( )} (0) ( ) ( ) / . i Pa P c c X . The capacity ( )i C 将作为第 i 层分量码的码率设计依据。The total capacity C of a Random variables Outcome