main.m

卷积码的Viterbi译码算法仿真程序 要求：递归卷积码

%  main
close all;
clear all;


global  state_num;
global  memory_len;

global  state_inbits;
global  state_outbits1;
global  state_outbits2;


global gama;
global alpha;




frame_len=400;
frame_num=100;
ViterbiInit;

%inbits=[1 0 1 0 0 1 1 1]
%tx_bits  = Encoder( inbits )

%L=length(tx_bits);
%rx_bits=tx_bits+wgn(L,2,1);

%[LLR,dec_outbits ] =ViterbiDecoder( 0,rx_bits );
%LLR
%dec_outbits 

pe=[];
for SNR=0:4
    SNR
    E=[];
    for n=1:frame_num
        inbits=randint(1,frame_len);
        tx_bits=encoder(inbits);
       
       L=length(tx_bits);
        Pn=-SNR;           %Eb=1=0dB
        rx_bits=tx_bits+wgn(L,2,Pn);
       
        [LLR,dec_outbits ] =ViterbiDecoder(Pn,rx_bits);
        
        E=[E abs(inbits-dec_outbits)];
    end
    pe=[pe mean(E)];
end

snr=(0:4);
semilogy(snr,pe);
grid