/*****************************************************************************//*   FIle Name : turbo_decoder.c                                             *//*   Description : WiMax OFDM FEC turbo Product code for Decoder             *//*   author : miffie                                                         *//*   Date   : Nov/15/05                                                      *//*   Copyright (c) 2005 miffie   All rights reserved.                        *//*****************************************************************************/struct binaryset turbo_decoder (struct binaryset datain,//                                struct binaryset exp,                               char fec_code_type, char Nsub ) {//input format must be 1  and each bit data is SOFT(0x0-0xf)//This solution is still not effcient.//This may be improved in  follwoing ways://1) cross check //     After the end of each itelation, the cross point between//     errored row and errored column may be an error. So, the point's//     data should be changed to 7 or 8.//2) Area//    viterbi_turbo2 is consuming huge area, so it must reduce the size,//    I guess 128 state should be reduced 32 using Marray method.int 	ii , jj , ll, repeat ;char 	tmp1 , tmp2 , shifter ;char	*pp ;struct 	binaryset bset0, bset1 , metric , exp0 ;char    bdat[ 64 ] ;char    edat[ 64 ] ;char    fdat[ 64 ] ;char  	parity, sum_parity, previous_sum ;char    fail ;char    rowtype, columntype ;char    row, column , nx, ny;//rowtype, columntype// 1:(16,11), 2:(32,26), 3(64,57),// 4:(8,7) , 5(16,15), 6:(32,31) 7:(64,63)//short Nfull[] = {384, 384, 768,768, 1152, 1152} ;//                               row column Ix  Iy  B  Qchar  btc_parameters[6][6] = { {  2,  1,    4,  2,  8, 6},                               {  2,  5,    0,  4,  0, 6},                               {  2,  2,    0,  8,  0, 4},                               {  3,  5,    7,  2, 30, 4},                               {  7,  2,    3, 13,  7, 5},                               {  6,  3,   13,  3,  7, 5} } ;  //Main     //X sizes    rowtype = btc_parameters[fec_code_type-7][0] ;    nx = (rowtype==1) ? 5 :         (rowtype==2) ? 6 :         (rowtype==3) ? 7 : 1 ;    row = (rowtype==1) ? 11 :         (rowtype==2) ? 26 :         (rowtype==3) ? 57 :         (rowtype==4) ? 7 :         (rowtype==5) ? 15 :         (rowtype==6) ? 31 : 63 ;    row -= btc_parameters[fec_code_type-7][2]  ; //row-Ix    nx = row + nx ;    //Y sizes    columntype = btc_parameters[fec_code_type-7][1] ;    ny = (columntype==1) ? 5 :         (columntype==2) ? 6 :         (columntype==3) ? 7 : 1 ;    column = (columntype==1) ? 11 :         (columntype==2) ? 26 :         (columntype==3) ? 57 :         (columntype==4) ? 7 :         (columntype==5) ? 15 :         (columntype==6) ? 31 : 63 ;    column -= btc_parameters[fec_code_type-7][3]  ; //column-Iy    ny = column + ny ;    if ((pp = (char *)malloc((nx*ny)*sizeof(char)) ) == NULL) {        PRINTF( " malloc failed in turbo_decoder.c\n") ;    } //fail    else { //allocated     PRINTF( "turbo_decoder.c size=0x%x\n", datain.size ) ;     repeat = 0 ;     sum_parity = 0x7e ;     previous_sum = 0x7f ;     //add padding     bset1 = pad_binaryset ( btc_parameters[fec_code_type-7][4]  ) ;     datain = cat_binaryset( bset1, datain ) ;     //Loop     while ((previous_sum>sum_parity) & (sum_parity>0))  { //repeat       previous_sum = sum_parity ;       /////////////////////////////////////////////////////////       //column check "This must be first"       //        Because correcting checks first can get better result.       /////////////////////////////////////////////////////////       for(jj=0;jj<nx;jj++) { //each  column          printf("\n %d itelation Column%d decoding...\n" , repeat , jj ) ;         //Extract column to bset1         //bset1 = extract_binaryset( datain, jj*nx,  nx ) ;         bset1.data = &bdat[0] ;         bset1.format = 1 ;         bset1.size = ny ;         for(ii=0;ii<ny;ii++) { //each bit             bset1.data[ii] = datain.data[ii*nx+jj] ;         } //each bit         //Extract expectation to exp0         //exp0.data = &edat[0] ;         //exp0.format = 0 ;         //exp0.size = ny ;         //for(ii=0;ii<ny;ii++) { //each bit         //    exp0.data[ii] = exp.data[ii*nx+jj] ;         //} //each bit         //print_binaryset( bset1) ;         if (columntype<4) { //lfsr           metric = viterbi_turbo1(columntype, bset1 , &parity) ;           //if (metric.data[0]>0) {           bset1 = viterbi_turbo2(columntype, bset1, metric, &parity ) ;           //}           //print_binaryset( bset1) ;         }//lfsr         bset0.format=0 ;         bset0.size=ny ;         bset0.data=&fdat[0] ;         //writeback to datain         for(ii=0;ii<ny;ii++) { //each bit              datain.data[ii*nx+jj] = bset1.data[ii] ;              bset0.data[ii] = (bset1.data[ii]>=8) ? 1 : 0 ;              //printf("%d data=%x parity=%x\n", ii, bset1.data[ii], parity) ;         } //each bit         sum_parity += parity ;         //printf(" %d itelation Column%d parity=%x\n", repeat, jj, parity) ;         //fail = compare_binaryset( exp0, bset0 ) ;       } //each column       //print_binaryset( datain ) ;       /////////////////////////////////////////////////////////       //row check       sum_parity= 0 ;       for(jj=0;jj<column;jj++) { //each  row          printf("\n %d itelation Row%d decoding...\n" , repeat , jj ) ;         bset1 = extract_binaryset( datain, jj*nx,  nx ) ;         //exp0 = extract_binaryset( exp, jj*nx,  nx ) ;         //print_binaryset( bset1) ;         metric = viterbi_turbo1(rowtype, bset1, &parity ) ;         //if (metric.data[0]>0) {         bset1 = viterbi_turbo2(rowtype, bset1, metric, &parity ) ;         //}         //print_binaryset( bset1 ) ;         //writeback to datain         bset0.format=0 ;         bset0.size=nx ;         bset0.data=&fdat[0] ;         for(ii=0;ii<nx;ii++) { //each bit              datain.data[jj*nx+ii] = bset1.data[ii] ;              bset0.data[ii] = (bset1.data[ii]>=8) ? 1 : 0 ;         } //each bit         sum_parity += parity ;         printf(" %d itelation Row%d parity=%x\n", repeat, jj, parity) ;         //fail = compare_binaryset( exp0, bset0 ) ;       } //each row       printf(" %d itelation sum_parity=%x\n", repeat, sum_parity) ;       //print_binaryset( datain ) ;       repeat++ ;      } //repeat       /////////////////////////////////////////////////////////       //Soft to Hard Decision       bset0.data = pp ;       bset0.size = row*column ;       bset0.format = 0 ;       ll=0 ;       for(jj=0;jj<column;jj++) { //each  row          for(ii=0;ii<row;ii++) { //each bit           if(ll<bset0.size)              bset0.data[ll++] = (datain.data[jj*nx+ii]>=8) ? 1 : 0 ;         } //each bit       } //each row       /////////////////////////////////////////////////////////       //remove padding       bset0 = extract_binaryset( bset0, btc_parameters[fec_code_type-7][4] +                            btc_parameters[fec_code_type-7][5],                            bset0.size-btc_parameters[fec_code_type-7][4] -                            btc_parameters[fec_code_type-7][5]) ;    } //allocated    free ( datain.data ) ;    bset0 = binary2byte( bset0 ) ;    return ( bset0 ) ;} //turbo_decoder