fecenc.c

这个文件包括wimax中所有的编解码源代码

/*****************************************************************************/
/*   FIle Name : fecenc.c                                                    */
/*   Description : WiFi OFDM FEC Encoder                                     */
/*   author : miffie                                                         */
/*   Date   : Nov/01/05                                                      */
/*   Copyright (c) 2005 miffie   All rights reserved.                        */
/*****************************************************************************/

struct binaryset fecenc(struct binaryset datain , 
                              char fec_code_type ,
                              short *randomizer_seed ) {
                        
  register int ii , jj ;
  char num_erasure ;
  char RR ;
  short  KK  , num_data , size  ;
  short  row, column, tmp1 ;
  struct  binaryset bset0, bset1, bset2 , bset3;
  unsigned char     data[256] ;
  short BSID = 7 ;
  short DIUC = 1 ;
  short frame_number = 1 ;
  //   rs_cc           RS_K  RS_T  RATE Ncpc
  char rs_cc[7][4] = {{   12,    0,   0,   1 },
                      {   24,    4,   1,   2 },
                      {   36,    2,   3,   2 },
                      {   48,    8,   1,   4 },
                      {   72,    4,   3,   4 },
                      {   96,    6,   2,   6 },
                      {  108,    6,   3,   6 } } ;
  char btc_block[] =  { 23, 35, 58, 77, 96, 120 } ;
  char ctc_block[] =  { 24, 32, 36, 48, 72, 96, 108 } ;
  char Nsub = 16 ;
  
  PRINTF("fecenc    fec_code_type=%d size=0x%x\n", fec_code_type , datain.size) ;
    //////////////////////////////////////////////////////////////////////////////
    // randomization
    //////////////////////////////////////////////////////////////////////////////
    print_binaryset(datain) ;
    bset0 = byte2binary_MSB( datain ) ;
    bset0 = randomizer( bset0 , randomizer_seed ) ; //only accept format= 0 (binary);
    bset0 = binary2byte_MSB( bset0 ) ;
    bset3 = pad_binaryset( 1 ) ; //tail byte for convolution encoder
    bset0 = cat_binaryset( bset0, bset3 ) ;
    print_binaryset(bset0) ;
 
    //////////////////////////////////////////////////////////////////////////////
    // Outer Code ( Reed-Solomon)
    //////////////////////////////////////////////////////////////////////////////
    /* encode data[] to produce parity in bb[].  Data input and parity output
       is in polynomial form
    */
    //KK= NN-RR ; //number of data inputs to encoder
    if(fec_code_type==0) { //BPSK
      bset2.size = bset0.size ;
      bset2.format = bset0.format ;
      bset2.data = bset0.data ;
    } //BPSK
    else if(fec_code_type<=6) { //RS
      bset2.size= 0 ;
      bset2.format= 1 ; //Byte
      size=bset0.size ;
      while (size >0 ) { //while
         if ( size > rs_cc[fec_code_type][0] ) { //fixed size
            bset1 = extract_binaryset( bset0, bset0.size-size, rs_cc[fec_code_type][0] ) ;
            bset1 =  encode_rs(bset1, rs_cc[fec_code_type][1]*2 ) ;
            print_binaryset( bset1 ) ;
            bset2 = cat_binaryset( bset2, bset1 ) ;
            size -= rs_cc[fec_code_type][0] ;
         } else {//lastword
            bset1 = extract_binaryset( bset0, bset0.size-size, size ) ;
            bset3 = pad_binaryset( rs_cc[fec_code_type][0]-size ) ; //stuff bytes
            //bset1 = cat_binaryset( bset1, bset3 ) ;
            bset1 =  encode_rs(bset1, rs_cc[fec_code_type][1]*2 ) ;
            //bset1.data[0] = 0x49 ;
            //bset1.data[1] = 0x31 ;
            //bset1.data[2] = 0x40 ;
            //bset1.data[3] = 0xbf ;
            print_binaryset( bset1 ) ;
            bset2 = cat_binaryset( bset2, bset1 ) ;
            size = 0 ;
         } //lastword
      } //while
    } //RS
    else if(fec_code_type<=12) { //BTC
      size=0 ;
      bset2.size= 0 ;
      bset2.format= 1 ; //Byte
      while (size < bset0.size ) { //while
          if ((bset0.size-size)<btc_block[fec_code_type-7])  {//shortened
            //This process is not the way written in p435 of 802.16.2004
            //The way is the spec does not make sense to me , because
            //No way for the decoder to get Ix,Iy,B,Q parameters. 
            bset1 = pad_binaryset( btc_block[fec_code_type-7] -(bset0.size-size) ) ;
            bset1.format =1 ; //Byte
            for(ii=0;ii<bset1.size;ii++) bset1.data[ii]=0xff ; //Stuff
            bset0 = cat_binaryset (bset0, bset1 ) ;
          }//shortened
          bset1 = extract_binaryset( bset0, size, btc_block[fec_code_type-7] ) ;
          bset1 = turboproduct(bset1, fec_code_type, Nsub ) ;
          bset2 = cat_binaryset( bset2, bset1 ) ;
          size += btc_block[fec_code_type-7] ;
      } //while
    }//BTC
    else { //CTC
      size=0 ;
      bset2.size= 0 ;
      bset2.format= 1 ; //Byte
      while (size < bset0.size ) { //while
          if ((bset0.size-size)<ctc_block[fec_code_type-13])  {//shortened
            bset1 = pad_binaryset( ctc_block[fec_code_type-13] -(bset0.size-size) ) ;
            bset1.format =1 ; //Byte
            for(ii=0;ii<bset1.size;ii++) bset1.data[ii]=0xff ; //Stuff
            bset0 = cat_binaryset (bset0, bset1 ) ;
          }//shortened
          bset1 = extract_binaryset( bset0, size, ctc_block[fec_code_type-13] ) ;
          bset1 = ctc_encoder(bset1, fec_code_type, Nsub ) ;
          bset2 = cat_binaryset( bset2, bset1 ) ;
          size += ctc_block[fec_code_type-13] ;
      } //while
    }//CTC
    print_binaryset(bset2) ;
  
    //////////////////////////////////////////////////////////////////////////////
    // Inner Code 
    //////////////////////////////////////////////////////////////////////////////
    if  (fec_code_type<=6) {
      bset2 = byte2binary_MSB( bset2 ) ;
      print_binaryset( bset2 ) ;
      bset2 =  convolution_encoder(bset2, rs_cc[fec_code_type][2]) ;
      print_binaryset( bset2 ) ;
    }
    return( bset2 ) ;
} //fecenc