int gc1[]={0,2};
                int gs1[]={1,0};
                int gc2[]={2,2};
                int gs2[]={0,1};
                int c1[]={0,0,1,1};
                int c2[]={0,1,0,1};
                int s1[]={0,0,1,1};
                int s2[]={0,1,0,1};
                int m,n,ls,id1,id2;    // ls is for last_state
                double temp1,temp2,temp3,temp4;
                int x1[4][4]={{0,2,0,2},{0,2,0,2},{1,3,1,3},{1,3,1,3}};
                int x2[4][4]={{0,2,2,0},{1,3,3,1},{0,2,2,0},{1,3,3,1}};
                int signal_re[4]={1,0,-1,0};
                int signal_im[4]={0,1,0,-1};
                int input_signal[4]={0,1,2,3}; 
                double distance[4]={0,0,0,0};
                  
                
                ls=0;  
                for (m=0;m<130;m++){
                    for (n=0;n<4;n++){
                        id1=x1[ls][n];
                        id2=x2[ls][n];
                        temp1=h1[m].re*signal_re[id1]-h1[m].im*signal_im[id1];
                        temp2=h2[m].re*signal_re[id2]-h2[m].im*signal_im[id2];
                        temp3=r[m].re-temp1-temp2;
                        temp1=h1[m].re*signal_im[id1]+h1[m].im*signal_re[id1];
                        temp2=h2[m].re*signal_im[id2]+h2[m].im*signal_re[id2];
                        temp4=r[m].im-temp1-temp2;
                        distance[n]=temp3*temp3+temp4*temp4;
                    }
                    temp1=999999;
                    id1=0;
                    for (n=0;n<4;n++){
                        if (distance[n]<temp1){
                            temp1=distance[n];
                            id1=n;
                        }
                    }
                    y[m]=input_signal[id1];  // output of the decode results
                    ls=id1;
                }