turboproduct.c

这个文件包括wimax中所有的编解码源代码

/*****************************************************************************/
/*   FIle Name : turboproduct.c                                              */
/*   Description : WiMax OFDM FEC turbo Product code for Encoder             */
/*   author : miffie                                                         */
/*   Date   : Nov/16/05                                                      */
/*   Copyright (c) 2005 miffie   All rights reserved.                        */
/*****************************************************************************/

//Parity calculation with LinearFeedbackShiftRegister
char lfsr ( char type , char datain, char shifter ) {
char check , tmp1 ;

     if(type==3)  { //x^6+x+1
             tmp1 = ((datain^(shifter>>5)) &0x1) ;
             check = (tmp1) ? ((shifter^0x01)<<1) + tmp1 :
                    (shifter<<1) ;
             check &= 0x3f ;
     } //x^6+x+1
     else if (type==2) { //x^5+x^2+1
             tmp1 = ((datain^(shifter>>4)) &0x1) ;
             check = (tmp1) ? ((shifter^0x02)<<1) + tmp1 :
                    (shifter<<1) ;
             check &= 0x1f ;
     }  //x^5+x^2+1
     else if (type==1) { //x^4+x^1+1
             tmp1 = ((datain^(shifter>>3)) &0x1) ;
             check = (tmp1) ? ((shifter^0x01)<<1) + tmp1 :
                    (shifter<<1) ;
             check &= 0x0f ;
     }  //x^4+x^1+1
     else { //x^3+x^1+1
             tmp1 = ((datain^(shifter>>2)) &0x1) ;
             check = (tmp1) ? ((shifter^0x01)<<1) + tmp1 :
                    (shifter<<1) ;
             check &= 0x07 ;
     }  //x^3+x^1+1
     //printf("shifter=%x datain=%x check=%x\n", shifter, datain , check ) ;
     return ( check ) ;
} //lfsr

struct binaryset turboproduct (struct binaryset datain,
                               char fec_code_type, char Nsub ) {
//input format must be 1 
int 	ii , jj , kk ;
char 	tmp1 , tmp2 , shifter, parity ;
char    nx, ny ;
char	*qq;
struct binaryset bset0 , bset1 ;
char    rowtype, columntype ;
char  row, column ;
//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  Q 
char  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 ;

    //build BTC
    if ((qq = (char *)malloc((nx*ny)*sizeof(char)) ) == NULL) {
        PRINTF( " malloc failed in turboproduct.c\n") ;
    } //fail
    else { //allocated
       PRINTF( "turboproduct.c size=%x\n", datain.size ) ;
       bset0  = byte2binary( datain ) ;
       bset1 = pad_binaryset ( btc_parameters[fec_code_type-7][4] + 
                            btc_parameters[fec_code_type-7][5] ) ;
       bset1 = cat_binaryset( bset1, bset0 ) ;
       bset0.format = 0 ; //a bit
       bset0.size = nx * ny  ; //
       bset0.data = qq ; //

       //row encoder
       for(jj=0;jj<column;jj++) { //each  row 
         printf("\n Row%d encoding..\n", jj) ;
         shifter = 0 ; //Linear Feedback Shift Register
         parity = 0 ;
         //data
         for(ii=0;ii<row;ii++) { //each bit
           kk=jj*row + ii ;
           if (kk <bset1.size)  
             *qq = bset1.data[kk] & 0x1 ;
           else *qq = 0 ; //padding
           //printf("(%d %d) " , jj, ii ) ;
           shifter = lfsr(rowtype, *qq, shifter ) ;
           parity ^= *qq &0x1 ;
           *qq++ ;
         } //each bit
         //checks 
          if (rowtype<4) { //lfsr
            tmp1= nx-row-1 ; 
            for(ii=0;ii<tmp1;ii++) { //each bit
             *qq = (shifter>>(tmp1-1-ii)) & 0x1 ;
             parity ^= *qq &0x1 ;
             *qq++ ;
            } //each bit
          } //lfsr
         //overall parity
         *qq++ = parity ;
       } //each row

       /////////////////////////////////////////////////////////
       //column encoder
       for(jj=0;jj<nx;jj++) { //each  column 
         printf("\n Column%d encoding..\n", jj) ;
         shifter = 0 ; //Linear Feedback Shift Register
         parity = 0 ;
         //data
         for(ii=0;ii<column;ii++) { //each bit
           kk=ii*nx + jj ;
           //printf("(%d %d) kk=%d " , jj, ii , kk ) ;
           tmp2 =  bset0.data[kk] & 0x1 ;
           shifter = lfsr(columntype, tmp2, shifter ) ;
           parity ^= tmp2 &0x1 ;
         } //each bit
         //checks 
         if (columntype<4) { //lfsr
           tmp1= nx-row-1 ; 
           for(ii=0;ii<tmp1;ii++) { //each bit
             bset0.data[jj+(column+ii)*nx] = (shifter>>(tmp1-1-ii)) & 0x1 ;
             parity ^= bset0.data[jj+(column+ii)*nx] &0x1 ;
           } //each bit
         } //lfsr
         //overall parity
         bset0.data[jj+(column+tmp1)*nx]  = parity ;
       } //each column
       //remove B individual bits from the first row
       bset0 = extract_binaryset ( bset0, btc_parameters[fec_code_type-7][4], 
                                          nx*ny-btc_parameters[fec_code_type-7][4] ) ;
    } //allocated
    //free ( datain.data ) ;
    return ( bset0 ) ;
} //turboproduct