function rx_init_viterbi

global sim_consts;
global prev_state;
global prev_state_outbits;

sim_consts = struct( 'ConvCodeGenPoly', [1 0 1 1 0 1 1;1 1 1 1 0 0 1 ]);%定義卷積編碼器的生成矩陣
prev_state = zeros(64, 2);
prev_state_outbits = zeros(64, 2, 2);

for state = 0:63
   state_bits = (fliplr(kron(dec2bin(state,6),1))~=48);%移位寄存器的狀態(tài)
   input_bit= state_bits(1)
   for transition = 0:1
      prev_state_bits = [state_bits(2:6) transition];%上一級(jí)的移位寄存器的狀態(tài)
      prev_state(state+1,transition+1) = base2dec(fliplr(prev_state_bits)+48,2);%用來存儲(chǔ)上一級(jí)移位寄存器狀態(tài)
      
      %第一個(gè)生成器的輸出碼字
      prev_state_outbits(state+1, transition+1, 1) = 2*(rem(sum(sim_consts.ConvCodeGenPoly(1,:).* ...
         [input_bit prev_state_bits ]),2)) - 1;
     %第二個(gè)生成器的輸出碼字
      prev_state_outbits(state+1, transition+1, 2) = 2*(rem(sum(sim_consts.ConvCodeGenPoly(2,:).* ...
         [input_bit prev_state_bits]),2)) - 1;
   end
end