308 lines
9.3 KiB
C
Executable File
308 lines
9.3 KiB
C
Executable File
/*******************************************************************************
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OpenAirInterface
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Copyright(c) 1999 - 2014 Eurecom
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OpenAirInterface is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenAirInterface is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with OpenAirInterface.The full GNU General Public License is
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included in this distribution in the file called "COPYING". If not,
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see <http://www.gnu.org/licenses/>.
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Contact Information
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OpenAirInterface Admin: openair_admin@eurecom.fr
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OpenAirInterface Tech : openair_tech@eurecom.fr
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OpenAirInterface Dev : openair4g-devel@eurecom.fr
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Address : Eurecom, Campus SophiaTech, 450 Route des Chappes, CS 50193 - 06904 Biot Sophia Antipolis cedex, FRANCE
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*******************************************************************************/
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/*
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* @defgroup _PHY_MODULATION_
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* @ingroup _physical_layer_ref_implementation_
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* @{
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\section _phy_modulation_ OFDM Modulation Blocks
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This section deals with basic functions for OFDM Modulation.
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*/
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#include "PHY/defs.h"
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#include "UTIL/LOG/log.h"
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//static short temp2[2048*4] __attribute__((aligned(16)));
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//#define DEBUG_OFDM_MOD
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void normal_prefix_mod(int32_t *txdataF,int32_t *txdata,uint8_t nsymb,LTE_DL_FRAME_PARMS *frame_parms) {
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uint8_t i;
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int short_offset=0;
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if ((2*nsymb) < frame_parms->symbols_per_tti)
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short_offset = 1;
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// printf("nsymb %d\n",nsymb);
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for (i=0;i<((short_offset)+2*nsymb/frame_parms->symbols_per_tti);i++) {
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#ifdef DEBUG_OFDM_MOD
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printf("slot i %d (txdata offset %d, txoutput %p)\n",i,(i*(frame_parms->samples_per_tti>>1)),
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txdata+(i*(frame_parms->samples_per_tti>>1)));
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#endif
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PHY_ofdm_mod(txdataF+(i*NUMBER_OF_OFDM_CARRIERS*frame_parms->symbols_per_tti>>1), // input
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txdata+(i*frame_parms->samples_per_tti>>1), // output
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frame_parms->log2_symbol_size, // log2_fft_size
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1, // number of symbols
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frame_parms->nb_prefix_samples0, // number of prefix samples
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frame_parms->twiddle_ifft, // IFFT twiddle factors
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frame_parms->rev, // bit-reversal permutation
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CYCLIC_PREFIX);
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#ifdef DEBUG_OFDM_MOD
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printf("slot i %d (txdata offset %d)\n",i,OFDM_SYMBOL_SIZE_COMPLEX_SAMPLES0+(i*frame_parms->samples_per_tti>>1));
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#endif
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PHY_ofdm_mod(txdataF+NUMBER_OF_OFDM_CARRIERS+(i*NUMBER_OF_OFDM_CARRIERS*(frame_parms->symbols_per_tti>>1)), // input
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txdata+OFDM_SYMBOL_SIZE_COMPLEX_SAMPLES0+(i*(frame_parms->samples_per_tti>>1)), // output
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frame_parms->log2_symbol_size, // log2_fft_size
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(short_offset==1) ? 1 :(frame_parms->symbols_per_tti>>1)-1,//6, // number of symbols
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frame_parms->nb_prefix_samples, // number of prefix samples
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frame_parms->twiddle_ifft, // IFFT twiddle factors
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frame_parms->rev, // bit-reversal permutation
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CYCLIC_PREFIX);
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}
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}
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void PHY_ofdm_mod(int *input, /// pointer to complex input
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int *output, /// pointer to complex output
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unsigned char log2fftsize, /// log2(FFT_SIZE)
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unsigned char nb_symbols, /// number of OFDM symbols
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unsigned short nb_prefix_samples, /// cyclic prefix length
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short *twiddle_ifft, /// pointer to precomputed twiddle table
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unsigned short *rev, /// pointer to bit-reversal table
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Extension_t etype /// type of extension
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) {
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static short temp[2048*4] __attribute__((aligned(16)));
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unsigned short i,j;
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short k;
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volatile int *output_ptr=(int*)0;
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int *temp_ptr=(int*)0;
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void (*idft)(int16_t *,int16_t *, int);
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switch (log2fftsize) {
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case 7:
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idft = idft128;
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break;
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case 8:
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idft = idft256;
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break;
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case 9:
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idft = idft512;
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break;
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case 10:
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idft = idft1024;
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break;
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case 11:
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idft = idft2048;
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break;
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default:
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idft = idft512;
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break;
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}
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#ifdef DEBUG_OFDM_MOD
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msg("[PHY] OFDM mod (size %d,prefix %d) Symbols %d, input %p, output %p\n",
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1<<log2fftsize,nb_prefix_samples,nb_symbols,input,output);
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#endif
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for (i=0;i<nb_symbols;i++){
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#ifdef DEBUG_OFDM_MOD
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msg("[PHY] symbol %d/%d (%p,%p -> %p)\n",i,nb_symbols,input,&input[i<<log2fftsize],&output[(i<<log2fftsize) + ((i)*nb_prefix_samples)]);
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#endif
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#ifndef NEW_FFT
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fft((short *)&input[i<<log2fftsize],
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temp,
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twiddle_ifft,
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rev,
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log2fftsize,
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log2fftsize/2, // normalized FFT (i.e. 1/sqrt(N) multiplicative factor)
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0);
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#else
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idft((int16_t *)&input[i<<log2fftsize],
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(log2fftsize==7) ? (int16_t *)temp : (int16_t *)&output[(i<<log2fftsize) + ((1+i)*nb_prefix_samples)],
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1);
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#endif
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// write_output("fft_out.m","fftout",temp,(1<<log2fftsize)*2,1,1);
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//memset(temp,0,1<<log2fftsize);
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// Copy to frame buffer with Cyclic Extension
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// Note: will have to adjust for synchronization offset!
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switch (etype) {
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case CYCLIC_PREFIX:
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output_ptr = &output[(i<<log2fftsize) + ((1+i)*nb_prefix_samples)];
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temp_ptr = (int *)temp;
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// msg("Doing cyclic prefix method\n");
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#ifndef NEW_FFT
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for (j=0;j<((1<<log2fftsize)) ; j++) {
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output_ptr[j] = temp_ptr[j];
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output_ptr[j] = temp_ptr[2*j];
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}
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#else
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if (log2fftsize==7) {
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for (j=0;j<((1<<log2fftsize)) ; j++) {
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output_ptr[j] = temp_ptr[j];
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}
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}
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j=(1<<log2fftsize);
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#endif
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for (k=-1;k>=-nb_prefix_samples;k--) {
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output_ptr[k] = output_ptr[--j];
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}
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break;
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case CYCLIC_SUFFIX:
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output_ptr = &output[(i<<log2fftsize)+ (i*nb_prefix_samples)];
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temp_ptr = (int *)temp;
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// msg("Doing cyclic suffix method\n");
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for (j=0;j<(1<<log2fftsize) ; j++) {
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output_ptr[j] = temp_ptr[2*j];
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}
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for (j=0;j<nb_prefix_samples;j++)
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output_ptr[(1<<log2fftsize)+j] = output_ptr[j];
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break;
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case ZEROS:
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break;
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case NONE:
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// msg("NO EXTENSION!\n");
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output_ptr = &output[(i<<log2fftsize)];
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temp_ptr = (int *)temp;
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for (j=0;j<(1<<log2fftsize) ; j++) {
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output_ptr[j] = temp_ptr[2*j];
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}
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break;
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default:
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break;
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}
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}
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/*
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printf("input %p, output %p, log2fftsize %d, nsymb %d\n",input,output,log2fftsize,nb_symbols);
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for (i=0;i<16;i++)
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printf("%d %d\n",((short *)input)[i<<1],((short *)input)[1+(i<<1)]);
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printf("------\n");
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for (i=0;i<16;i++)
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printf("%d %d\n",((short *)output)[i<<1],((short *)output)[1+(i<<1)]);
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*/
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}
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void do_OFDM_mod(mod_sym_t **txdataF, int32_t **txdata, uint32_t frame,uint16_t next_slot, LTE_DL_FRAME_PARMS *frame_parms) {
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int aa, slot_offset, slot_offset_F;
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slot_offset_F = (next_slot)*(frame_parms->ofdm_symbol_size)*((frame_parms->Ncp==1) ? 6 : 7);
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slot_offset = (next_slot)*(frame_parms->samples_per_tti>>1);
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for (aa=0; aa<frame_parms->nb_antennas_tx; aa++) {
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if (is_pmch_subframe(frame,next_slot>>1,frame_parms)) {
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if ((next_slot%2)==0) {
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LOG_D(PHY,"Frame %d, subframe %d: Doing MBSFN modulation (slot_offset %d)\n",frame,next_slot>>1,slot_offset);
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PHY_ofdm_mod(&txdataF[aa][slot_offset_F], // input
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&txdata[aa][slot_offset], // output
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frame_parms->log2_symbol_size, // log2_fft_size
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12, // number of symbols
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frame_parms->ofdm_symbol_size>>2, // number of prefix samples
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frame_parms->twiddle_ifft, // IFFT twiddle factors
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frame_parms->rev, // bit-reversal permutation
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CYCLIC_PREFIX);
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if (frame_parms->Ncp == EXTENDED)
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PHY_ofdm_mod(&txdataF[aa][slot_offset_F], // input
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&txdata[aa][slot_offset], // output
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frame_parms->log2_symbol_size, // log2_fft_size
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2, // number of symbols
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frame_parms->nb_prefix_samples, // number of prefix samples
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frame_parms->twiddle_ifft, // IFFT twiddle factors
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frame_parms->rev, // bit-reversal permutation
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CYCLIC_PREFIX);
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else {
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LOG_D(PHY,"Frame %d, subframe %d: Doing PDCCH modulation\n",frame,next_slot>>1);
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normal_prefix_mod(&txdataF[aa][slot_offset_F],
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&txdata[aa][slot_offset],
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2,
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frame_parms);
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}
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}
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}
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else {
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if (frame_parms->Ncp == EXTENDED)
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PHY_ofdm_mod(&txdataF[aa][slot_offset_F], // input
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&txdata[aa][slot_offset], // output
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frame_parms->log2_symbol_size, // log2_fft_size
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6, // number of symbols
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frame_parms->nb_prefix_samples, // number of prefix samples
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frame_parms->twiddle_ifft, // IFFT twiddle factors
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frame_parms->rev, // bit-reversal permutation
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CYCLIC_PREFIX);
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else {
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normal_prefix_mod(&txdataF[aa][slot_offset_F],
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&txdata[aa][slot_offset],
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7,
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frame_parms);
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}
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}
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}
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}
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/** @} */
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