说明：   set up the trellis given code generator g g given in binary matrix form. e.g. g = [ 1 1 1 1 0 1 ] next_out(i,1:2): trellis next_out (systematic bit parity bit) when input = 0, state = i next_out(i,j) = -1 or 1 next_out(i,3:4): trellis next_out (systematic bit parity bit) when input = 1, state = i next_state(i,1): next state when input = 0, state = i next_state(i,i) = 1,...2^m next_state(i,2): next state when input = 1, state = i last_out(i,1:2): trellis last_out (systematic bit parity bit) when input = 0, state = i last_out(i,j) = -1 or 1 last_out(i,3:4): trellis last_out (systematic bit parity bit) when input = 1, state = i last_state(i,1): previous state that comes to state i when info. bit = 0 last_state(i,2): previous state that comes to state i when info. bit = 1