ofdm_mod.c 8.97 KB
Newer Older
ghaddab's avatar
ghaddab committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
/*******************************************************************************
    OpenAirInterface 
    Copyright(c) 1999 - 2014 Eurecom

    OpenAirInterface is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.


    OpenAirInterface is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with OpenAirInterface.The full GNU General Public License is 
   included in this distribution in the file called "COPYING". If not, 
   see <http://www.gnu.org/licenses/>.

  Contact Information
  OpenAirInterface Admin: openair_admin@eurecom.fr
  OpenAirInterface Tech : openair_tech@eurecom.fr
  OpenAirInterface Dev  : openair4g-devel@eurecom.fr
  
ghaddab's avatar
ghaddab committed
26
  Address      : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
ghaddab's avatar
ghaddab committed
27 28

 *******************************************************************************/
29 30 31 32 33 34 35 36 37 38 39
/*
* @defgroup _PHY_MODULATION_
* @ingroup _physical_layer_ref_implementation_
* @{
\section _phy_modulation_ OFDM Modulation Blocks
This section deals with basic functions for OFDM Modulation.


*/

#include "PHY/defs.h"
Raymond Knopp's avatar
 
Raymond Knopp committed
40
#include "UTIL/LOG/log.h"
41 42 43 44 45 46
 
//static short temp2[2048*4] __attribute__((aligned(16)));

//#define DEBUG_OFDM_MOD


47
void normal_prefix_mod(int32_t *txdataF,int32_t *txdata,uint8_t nsymb,LTE_DL_FRAME_PARMS *frame_parms) {
48

49
  uint8_t i;
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227
  int short_offset=0;

  if ((2*nsymb) < frame_parms->symbols_per_tti)
    short_offset = 1;

  //  printf("nsymb %d\n",nsymb);
  for (i=0;i<((short_offset)+2*nsymb/frame_parms->symbols_per_tti);i++) {

#ifdef DEBUG_OFDM_MOD
        printf("slot i %d (txdata offset %d, txoutput %p)\n",i,(i*(frame_parms->samples_per_tti>>1)),
	       txdata+(i*(frame_parms->samples_per_tti>>1)));
#endif
    
    PHY_ofdm_mod(txdataF+(i*NUMBER_OF_OFDM_CARRIERS*frame_parms->symbols_per_tti>>1),        // input
		 txdata+(i*frame_parms->samples_per_tti>>1),         // output
		 frame_parms->log2_symbol_size,                // log2_fft_size
		 1,                 // number of symbols
		 frame_parms->nb_prefix_samples0,               // number of prefix samples
		 frame_parms->twiddle_ifft,  // IFFT twiddle factors
		 frame_parms->rev,           // bit-reversal permutation
		 CYCLIC_PREFIX);
#ifdef DEBUG_OFDM_MOD
        printf("slot i %d (txdata offset %d)\n",i,OFDM_SYMBOL_SIZE_COMPLEX_SAMPLES0+(i*frame_parms->samples_per_tti>>1));
#endif    

    PHY_ofdm_mod(txdataF+NUMBER_OF_OFDM_CARRIERS+(i*NUMBER_OF_OFDM_CARRIERS*(frame_parms->symbols_per_tti>>1)),        // input
		 txdata+OFDM_SYMBOL_SIZE_COMPLEX_SAMPLES0+(i*(frame_parms->samples_per_tti>>1)),         // output
		 frame_parms->log2_symbol_size,                // log2_fft_size
		 (short_offset==1) ? 1 :(frame_parms->symbols_per_tti>>1)-1,//6,                 // number of symbols
		 frame_parms->nb_prefix_samples,               // number of prefix samples
		 frame_parms->twiddle_ifft,  // IFFT twiddle factors
		 frame_parms->rev,           // bit-reversal permutation
		 CYCLIC_PREFIX);
    

  }
}

void PHY_ofdm_mod(int *input,                       /// pointer to complex input
	          int *output,                      /// pointer to complex output
	          unsigned char log2fftsize,        /// log2(FFT_SIZE)
	          unsigned char nb_symbols,         /// number of OFDM symbols
	          unsigned short nb_prefix_samples,  /// cyclic prefix length
		  short *twiddle_ifft,              /// pointer to precomputed twiddle table
		  unsigned short *rev,              /// pointer to bit-reversal table
		  Extension_t etype                /// type of extension
) {

  static short temp[2048*4] __attribute__((aligned(16)));
  unsigned short i,j;
  short k;

  volatile int *output_ptr=(int*)0;

  int *temp_ptr=(int*)0;
  void (*idft)(int16_t *,int16_t *, int);

  switch (log2fftsize) {
  case 7:
    idft = idft128;
    break;
  case 8:
    idft = idft256;
    break;
  case 9:
    idft = idft512;
    break;
  case 10:
    idft = idft1024;
    break;
  case 11:
    idft = idft2048;
    break;
  default:
    idft = idft512;
    break;
  }

#ifdef DEBUG_OFDM_MOD
  msg("[PHY] OFDM mod (size %d,prefix %d) Symbols %d, input %p, output %p\n",
      1<<log2fftsize,nb_prefix_samples,nb_symbols,input,output);
#endif


  
  for (i=0;i<nb_symbols;i++){

#ifdef DEBUG_OFDM_MOD
    msg("[PHY] symbol %d/%d (%p,%p -> %p)\n",i,nb_symbols,input,&input[i<<log2fftsize],&output[(i<<log2fftsize) + ((i)*nb_prefix_samples)]);
#endif

    idft((int16_t *)&input[i<<log2fftsize],
	 (log2fftsize==7) ? (int16_t *)temp : (int16_t *)&output[(i<<log2fftsize) + ((1+i)*nb_prefix_samples)],
	 1);
    //    write_output("fft_out.m","fftout",temp,(1<<log2fftsize)*2,1,1);

    //memset(temp,0,1<<log2fftsize);
    
  
    // Copy to frame buffer with Cyclic Extension
    // Note:  will have to adjust for synchronization offset!
    
    switch (etype) {
    case CYCLIC_PREFIX:
      output_ptr = &output[(i<<log2fftsize) + ((1+i)*nb_prefix_samples)];
      temp_ptr = (int *)temp;
      

      //      msg("Doing cyclic prefix method\n");

      if (log2fftsize==7) {
	for (j=0;j<((1<<log2fftsize)) ; j++) {
	  output_ptr[j] = temp_ptr[j];
	}
      }
      j=(1<<log2fftsize);
      
      for (k=-1;k>=-nb_prefix_samples;k--) {
	output_ptr[k] = output_ptr[--j];
      }
      break;
      
    case CYCLIC_SUFFIX:
      
      
      output_ptr = &output[(i<<log2fftsize)+ (i*nb_prefix_samples)];
      
      temp_ptr = (int *)temp;
      
      //      msg("Doing cyclic suffix method\n");

      for (j=0;j<(1<<log2fftsize) ; j++) {
	output_ptr[j] = temp_ptr[2*j];
      }
      
      
      for (j=0;j<nb_prefix_samples;j++)
	output_ptr[(1<<log2fftsize)+j] = output_ptr[j];
      
      break;

    case ZEROS:

      break;

    case NONE:

      //      msg("NO EXTENSION!\n");
      output_ptr = &output[(i<<log2fftsize)];

      temp_ptr = (int *)temp;
      
      for (j=0;j<(1<<log2fftsize) ; j++) {
	output_ptr[j] = temp_ptr[2*j];


      }

      break;

    default:
      break;

    }
    

    
  }
  /*
  printf("input %p, output %p, log2fftsize %d, nsymb %d\n",input,output,log2fftsize,nb_symbols);
  for (i=0;i<16;i++)
    printf("%d %d\n",((short *)input)[i<<1],((short *)input)[1+(i<<1)]);
  printf("------\n");
  for (i=0;i<16;i++)
    printf("%d %d\n",((short *)output)[i<<1],((short *)output)[1+(i<<1)]);  
  */
}

Raymond Knopp's avatar
 
Raymond Knopp committed
228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287

void do_OFDM_mod(mod_sym_t **txdataF, int32_t **txdata, uint32_t frame,uint16_t next_slot, LTE_DL_FRAME_PARMS *frame_parms) {

  int aa, slot_offset, slot_offset_F;

  slot_offset_F = (next_slot)*(frame_parms->ofdm_symbol_size)*((frame_parms->Ncp==1) ? 6 : 7);
  slot_offset = (next_slot)*(frame_parms->samples_per_tti>>1);
  
  for (aa=0; aa<frame_parms->nb_antennas_tx; aa++) {
   if (is_pmch_subframe(frame,next_slot>>1,frame_parms)) {
      if ((next_slot%2)==0) {
	LOG_D(PHY,"Frame %d, subframe %d: Doing MBSFN modulation (slot_offset %d)\n",frame,next_slot>>1,slot_offset); 
	PHY_ofdm_mod(&txdataF[aa][slot_offset_F],        // input
		     &txdata[aa][slot_offset],         // output
		     frame_parms->log2_symbol_size,                // log2_fft_size
		     12,                 // number of symbols
		     frame_parms->ofdm_symbol_size>>2,               // number of prefix samples
		     frame_parms->twiddle_ifft,  // IFFT twiddle factors
		     frame_parms->rev,           // bit-reversal permutation
		     CYCLIC_PREFIX);
     
	if (frame_parms->Ncp == EXTENDED)
	  PHY_ofdm_mod(&txdataF[aa][slot_offset_F],        // input
		       &txdata[aa][slot_offset],         // output
		       frame_parms->log2_symbol_size,                // log2_fft_size
		       2,                 // number of symbols
		       frame_parms->nb_prefix_samples,               // number of prefix samples
		       frame_parms->twiddle_ifft,  // IFFT twiddle factors
		       frame_parms->rev,           // bit-reversal permutation
		       CYCLIC_PREFIX);
	else {
	  LOG_D(PHY,"Frame %d, subframe %d: Doing PDCCH modulation\n",frame,next_slot>>1); 
	  normal_prefix_mod(&txdataF[aa][slot_offset_F],
			    &txdata[aa][slot_offset],
			    2,
			    frame_parms);
	}      
      }
    }
    else {
      if (frame_parms->Ncp == EXTENDED)
	PHY_ofdm_mod(&txdataF[aa][slot_offset_F],        // input
		     &txdata[aa][slot_offset],         // output
		     frame_parms->log2_symbol_size,                // log2_fft_size
		     6,                 // number of symbols
		     frame_parms->nb_prefix_samples,               // number of prefix samples
		     frame_parms->twiddle_ifft,  // IFFT twiddle factors
		     frame_parms->rev,           // bit-reversal permutation
		     CYCLIC_PREFIX);
      else {
	normal_prefix_mod(&txdataF[aa][slot_offset_F],
			  &txdata[aa][slot_offset],
			  7,
			  frame_parms);
      }
    }  
  }
  
}

288
/** @} */