nr_dci.c

/*
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 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (the "License"); you may not use this file
 * except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.openairinterface.org/?page_id=698
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
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 * See the License for the specific language governing permissions and
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 *-------------------------------------------------------------------------------
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/*! \file PHY/NR_TRANSPORT/nr_dci.c
* \brief Implements DCI encoding and PDCCH TX procedures (38.212/38.213/38.214). V15.4.0 2019-01.
* \author Guy De Souza
* \date 2018
* \version 0.1
* \company Eurecom
* \email: desouza@eurecom.fr
* \note
* \warning
*/

#include "nr_dci.h"

//#define DEBUG_PDCCH_DMRS
#define DEBUG_DCI
#define DEBUG_CHANNEL_CODING


extern short nr_mod_table[NR_MOD_TABLE_SIZE_SHORT];

uint16_t nr_get_dci_size(nfapi_nr_dci_format_e format,
                        nfapi_nr_rnti_type_e rnti_type,
                        uint16_t N_RB,
                        nfapi_nr_config_request_t* config)
{
  uint16_t size = 0;

  switch(format) {
/*Only sizes for 0_0 and 1_0 are correct at the moment*/
    case NFAPI_NR_UL_DCI_FORMAT_0_0:
      /// fixed: Format identifier 1, Hop flag 1, MCS 5, NDI 1, RV 2, HARQ PID 4, PUSCH TPC 2 Time Domain assgnmt 4 --20
      size += 20;
      size += (uint8_t)ceil( log2( (N_RB*(N_RB+1))>>1 ) ); // Freq domain assignment -- hopping scenario to be updated
      size += nr_get_dci_size(NFAPI_NR_DL_DCI_FORMAT_1_0, rnti_type, N_RB, config) - size; // Padding to match 1_0 size
      // UL/SUL indicator assumed to be 0
      break;

    case NFAPI_NR_UL_DCI_FORMAT_0_1:
      /// fixed: Format identifier 1, MCS 5, NDI 1, RV 2, HARQ PID 4, PUSCH TPC 2, SRS request 2 --17
      size += 17;
      // Carrier indicator
      // UL/SUL indicator
      // BWP Indicator
      // Freq domain assignment
      // Time domain assignment
      // VRB to PRB mapping
      // Frequency Hopping flag
      // 1st DAI
      // 2nd DAI
      // SRS resource indicator
      // Precoding info and number of layers
      // Antenna ports
      // CSI request
      // CBGTI
      // PTRS - DMRS association
      // beta offset indicator
      // DMRS sequence init
      break;

    case NFAPI_NR_DL_DCI_FORMAT_1_0:
      /// fixed: Format identifier 1, VRB2PRB 1, MCS 5, NDI 1, RV 2, HARQ PID 4, DAI 2, PUCCH TPC 2, PUCCH RInd 3, PDSCH to HARQ TInd 3 Time Domain assgnmt 4 -- 28
      size += 28;
      size += (uint8_t)ceil( log2( (N_RB*(N_RB+1))>>1 ) ); // Freq domain assignment

      break;

    case NFAPI_NR_DL_DCI_FORMAT_1_1:
      // Carrier indicator
      size += 1; // Format identifier
      // BWP Indicator
      // Freq domain assignment
      // Time domain assignment
      // VRB to PRB mapping
      // PRB bundling size indicator
      // Rate matching indicator
      // ZP CSI-RS trigger
        /// TB1- MCS 5, NDI 1, RV 2
      size += 8;
      // TB2
      size += 4 ;  // HARQ PID
      // DAI
      size += 2; // TPC PUCCH
      size += 3; // PUCCH resource indicator
      size += 3; // PDSCH to HARQ timing indicator
      // Antenna ports
      // Tx Config Indication
      size += 2; // SRS request
      // CBGTI
      // CBGFI
      size += 1; // DMRS sequence init
      
      break;

    case NFAPI_NR_DL_DCI_FORMAT_2_0:
      break;

    case NFAPI_NR_DL_DCI_FORMAT_2_1:
      break;

    case NFAPI_NR_DL_DCI_FORMAT_2_2:
      break;

    case NFAPI_NR_DL_DCI_FORMAT_2_3:
      break;

  default:
    AssertFatal(1==0, "Invalid NR DCI format %d\n", format);
  }

  return size;
}

void nr_pdcch_scrambling(uint32_t *in,
                         uint16_t size,
                         uint32_t Nid,
                         uint32_t n_RNTI,
                         uint32_t* out) {

  uint8_t reset;
  uint32_t x1, x2, s=0;

  reset = 1;
  x2 = (n_RNTI<<16) + Nid;

  for (int i=0; i<size; i++) {
    if ((i&0x1f)==0) {
      s = lte_gold_generic(&x1, &x2, reset);
      reset = 0;
      if (i){
	in++;
	out++;
      }
    }
    (*out) ^= ((((*in)>>(i&0x1f))&1) ^ ((s>>(i&0x1f))&1))<<(i&0x1f);
        //printf("nr_pdcch_scrambling: in %d seq 0x%08x => out %d\n",((*in)>>(i&0x1f))&1,s,((*out)>>(i&0x1f))&1);
  }

}

uint8_t nr_generate_dci_top(NR_gNB_PDCCH pdcch_vars,
			    t_nrPolar_paramsPtr *nrPolar_params,
                            uint32_t **gold_pdcch_dmrs,
                            int32_t* txdataF,
                            int16_t amp,
                            NR_DL_FRAME_PARMS frame_parms,
                            nfapi_nr_config_request_t config)
{

  int16_t mod_dmrs[NR_MAX_CSET_DURATION][NR_MAX_PDCCH_DMRS_LENGTH>>1]; // 3 for the max coreset duration
  uint32_t dmrs_seq[NR_MAX_PDCCH_DMRS_INIT_LENGTH_DWORD];
  uint16_t dmrs_offset=0;
  uint16_t cset_start_sc;
  uint8_t cset_start_symb, cset_nsymb;
  int k,l,k_prime,dci_idx, dmrs_idx;
  nr_cce_t cce;
  nr_reg_t reg;
  nr_reg_t reg_mapping_list[NR_MAX_PDCCH_AGG_LEVEL*NR_NB_REG_PER_CCE];

  /*First iteration: single DCI*/
  NR_gNB_DCI_ALLOC_t dci_alloc = pdcch_vars.dci_alloc[0];
  nfapi_nr_dl_config_pdcch_parameters_rel15_t pdcch_params = dci_alloc.pdcch_params;

  /*The coreset is initialised
  * in frequency: the first subcarrier is obtained by adding the first CRB overlapping the SSB and the rb_offset for coreset 0
  * or the rb_offset for other coresets
  * in time: by its first slot and its first symbol*/
  if (pdcch_params.config_type == NFAPI_NR_CSET_CONFIG_MIB_SIB1){
    cset_start_sc = frame_parms.first_carrier_offset + (frame_parms.ssb_start_subcarrier/NR_NB_SC_PER_RB +
    pdcch_params.rb_offset)*NR_NB_SC_PER_RB;
  }
  else
    cset_start_sc = frame_parms.first_carrier_offset + pdcch_params.rb_offset*NR_NB_SC_PER_RB;

  cset_start_symb = pdcch_params.first_symbol;
  cset_nsymb = pdcch_params.n_symb;
  dci_idx = 0;
  LOG_I(PHY, "Coreset starting subcarrier %d on symbol %d (%d symbols)\n", cset_start_sc, cset_start_symb, cset_nsymb);

  // DMRS length is per OFDM symbol
  uint16_t dmrs_length = (pdcch_params.precoder_granularity == NFAPI_NR_CSET_ALL_CONTIGUOUS_RBS)?
  (pdcch_params.n_rb*6) : (dci_alloc.L*36/cset_nsymb); //2(QPSK)*3(per RB)*6(REG per CCE)
  uint16_t encoded_length = dci_alloc.L*108; //2(QPSK)*9(per RB)*6(REG per CCE)
  LOG_I(PHY, "DMRS length per symbol %d\t DCI encoded length %d\n", dmrs_length, encoded_length);


  /// DMRS QPSK modulation
    /*There is a need to shift from which index the pregenerated DMRS sequence is used
     * see 38211 r15.2.0 section 7.4.1.3.2: assumption is the reference point for k refers to the DMRS sequence*/
  if (pdcch_params.config_type == NFAPI_NR_CSET_CONFIG_PDCCH_CONFIG) {
    for (int symb=cset_start_symb; symb<cset_start_symb + pdcch_params.n_symb; symb++)
      gold_pdcch_dmrs[symb] += (pdcch_params.rb_offset*3)>>5;
    dmrs_offset = (pdcch_params.rb_offset*3)&0x1f;
  LOG_I(PHY, "PDCCH DMRS offset %d\n", dmrs_offset);
  }

  for (int symb=cset_start_symb; symb<cset_start_symb + pdcch_params.n_symb; symb++) {
    if (dmrs_offset) {
      // a non zero offset requires the DMRS sequence to be rearranged
      memset(dmrs_seq,0, NR_MAX_PDCCH_DMRS_INIT_LENGTH_DWORD*sizeof(uint32_t));
      for (int i=0; i<dmrs_length; i++) {
        dmrs_seq[(i>>5)] |= ((gold_pdcch_dmrs[symb][(i+dmrs_offset)>>5]>>((i+dmrs_offset)&0x1f))&1)<<(i&0x1f);
#ifdef DEBUG_PDCCH_DMRS
  //printf("out 0x%08x in 0x%08x \n", dmrs_seq[(i>>5)], gold_pdcch_dmrs[symb][(i+dmrs_offset)>>5]);
#endif
      }
      nr_modulation(dmrs_seq, dmrs_length, MOD_QPSK, mod_dmrs[symb]);
    }
    else
      nr_modulation(gold_pdcch_dmrs[symb], dmrs_length, MOD_QPSK, mod_dmrs[symb]);

#ifdef DEBUG_PDCCH_DMRS
  for (int i=0; i<dmrs_length>>1; i++)
    if (dmrs_offset)
      printf("symb %d i %d gold seq 0x%08x mod_dmrs %d %d\n", symb, i, dmrs_seq[i>>5],
      mod_dmrs[symb][i<<1], mod_dmrs[symb][(i<<1)+1] );
    else
      printf("symb %d i %d gold seq 0x%08x mod_dmrs %d %d\n", symb, i,
      gold_pdcch_dmrs[symb][i>>5], mod_dmrs[symb][i<<1], mod_dmrs[symb][(i<<1)+1] );
#endif

  }


  /// DCI payload processing
    // CRC attachment + Scrambling + Channel coding + Rate matching
  uint32_t encoder_output[NR_MAX_DCI_SIZE_DWORD];
  uint16_t n_RNTI = (pdcch_params.search_space_type == NFAPI_NR_SEARCH_SPACE_TYPE_UE_SPECIFIC)? pdcch_params.rnti:0;
  uint16_t Nid = (pdcch_params.search_space_type == NFAPI_NR_SEARCH_SPACE_TYPE_UE_SPECIFIC)?
  pdcch_params.scrambling_id : config.sch_config.physical_cell_id.value;

  nr_polar_init(nrPolar_params, NR_POLAR_DCI_MESSAGE_TYPE, dci_alloc.size, dci_alloc.L);
  t_nrPolar_paramsPtr currentPtr = nr_polar_params(*nrPolar_params, NR_POLAR_DCI_MESSAGE_TYPE, dci_alloc.size, dci_alloc.L);

  polar_encoder_fast(dci_alloc.dci_pdu, encoder_output, pdcch_params.rnti,currentPtr);

#ifdef DEBUG_CHANNEL_CODING
  printf("polar rnti %d\n",pdcch_params.rnti);
  printf("DCI PDU: [0]->0x%lx \t [1]->0x%lx\n",
    dci_alloc.dci_pdu[0], dci_alloc.dci_pdu[1]);
  printf("Encoded Payload (length:%d dwords):\n", encoded_length>>5);
  for (int i=0;i<encoded_length>>5;i++)
    printf("[%d]->0x%08x \t", i,encoder_output[i]);
  printf("\n");
#endif

  /// Scrambling
  uint32_t scrambled_output[NR_MAX_DCI_SIZE_DWORD]={0};
  nr_pdcch_scrambling(encoder_output, encoded_length, Nid, n_RNTI, scrambled_output);
#ifdef DEBUG_CHANNEL_CODING
printf("scrambled output: [0]->0x%08x \t [1]->0x%08x \t [2]->0x%08x \t [3]->0x%08x\t [4]->0x%08x\t [5]->0x%08x\t \
[6]->0x%08x \t [7]->0x%08x \t [8]->0x%08x \t [9]->0x%08x\t [10]->0x%08x\t [11]->0x%08x\n",
		  scrambled_output[0], scrambled_output[1], scrambled_output[2], scrambled_output[3], scrambled_output[4],scrambled_output[5],
		  scrambled_output[6], scrambled_output[7], scrambled_output[8], scrambled_output[9], scrambled_output[10],scrambled_output[11] );	
#endif

  /// QPSK modulation
  int16_t mod_dci[NR_MAX_DCI_SIZE>>1];
  nr_modulation(scrambled_output, encoded_length, MOD_QPSK, mod_dci);
#ifdef DEBUG_DCI
  for (int i=0; i<encoded_length>>1; i++)
    printf("i %d mod_dci %d %d\n", i, mod_dci[i<<1], mod_dci[(i<<1)+1] );
#endif

  /// Resource mapping

    if (cset_start_sc >= frame_parms.ofdm_symbol_size)
      cset_start_sc -= frame_parms.ofdm_symbol_size;


    /*Reorder REG list for a freq first mapping*/
    uint8_t symb_idx[NR_MAX_CSET_DURATION] = {0,0,0};
    uint8_t nb_regs = dci_alloc.L*NR_NB_REG_PER_CCE;
    uint8_t regs_per_symb = nb_regs/cset_nsymb;
    for (int cce_idx=0; cce_idx<dci_alloc.L; cce_idx++){
      cce = dci_alloc.cce_list[cce_idx];
      for (int reg_idx=0; reg_idx<NR_NB_REG_PER_CCE; reg_idx++) {
        reg = cce.reg_list[reg_idx];
        reg_mapping_list[reg.symb_idx*regs_per_symb + symb_idx[reg.symb_idx]++] = reg;
      }
    }
#ifdef DEBUG_DCI
    printf("\n Ordered REG list:\n");
    for (int i=0; i<nb_regs; i++)
      printf("%d\t",reg_mapping_list[i].reg_idx );
    printf("\n");
#endif
    
    if (pdcch_params.precoder_granularity == NFAPI_NR_CSET_ALL_CONTIGUOUS_RBS) {
    /*in this case the DMRS are mapped on all the coreset*/
      for (l=cset_start_symb; l<cset_start_symb+ cset_nsymb; l++) {
        dmrs_idx = 0;
        k = cset_start_sc + 1;
        while (dmrs_idx<3*pdcch_params.n_rb) {
          ((int16_t*)txdataF)[(l*frame_parms.ofdm_symbol_size + k)<<1]       = ((amp>>1) * mod_dmrs[l][dmrs_idx<<1]) >> 15;
          ((int16_t*)txdataF)[((l*frame_parms.ofdm_symbol_size + k)<<1) + 1] = ((amp>>1) * mod_dmrs[l][(dmrs_idx<<1) + 1]) >> 15;
#ifdef DEBUG_PDCCH_DMRS
  printf("symbol %d position %d => (%d,%d)\n",l,k,((int16_t*)txdataF)[(l*frame_parms.ofdm_symbol_size + k)<<1] ,
  ((int16_t*)txdataF)[((l*frame_parms.ofdm_symbol_size + k)<<1)+1]);
#endif
          k+=4;
          if (k >= frame_parms.ofdm_symbol_size)
            k -= frame_parms.ofdm_symbol_size;
          dmrs_idx++;
        }
      }    
    }

    /*Now mapping the encoded DCI based on newly constructed REG list
     * and the DMRS for the precoder granularity same as REG bundle*/
    for (int reg_idx=0; reg_idx<nb_regs; reg_idx++) {
      reg = reg_mapping_list[reg_idx];
      k = cset_start_sc + reg.start_sc_idx;
      if (k >= frame_parms.ofdm_symbol_size)
          k -= frame_parms.ofdm_symbol_size;
      l = cset_start_symb + reg.symb_idx;
      dmrs_idx = (reg.reg_idx/cset_nsymb)*3;
      k_prime = 0;
      for (int m=0; m<NR_NB_SC_PER_RB; m++) {
        if ( m == (k_prime<<2)+1) { // DMRS if not already mapped
          if (pdcch_params.precoder_granularity == NFAPI_NR_CSET_SAME_AS_REG_BUNDLE) {
            ((int16_t*)txdataF)[(l*frame_parms.ofdm_symbol_size + k)<<1]       = ((amp>>1) * mod_dmrs[l][dmrs_idx<<1]) >> 15;
            ((int16_t*)txdataF)[((l*frame_parms.ofdm_symbol_size + k)<<1) + 1] = ((amp>>1) * mod_dmrs[l][(dmrs_idx<<1) + 1]) >> 15;
#ifdef DEBUG_PDCCH_DMRS
  printf("l %d position %d => (%d,%d)\n",l,k,((int16_t*)txdataF)[(l*frame_parms.ofdm_symbol_size + k)<<1] ,
  ((int16_t*)txdataF)[((l*frame_parms.ofdm_symbol_size + k)<<1)+1]);
#endif
            dmrs_idx++;
          }
          k_prime++;
        }
        else { // DCI payload
          ((int16_t*)txdataF)[(l*frame_parms.ofdm_symbol_size + k)<<1]       = (amp * mod_dci[dci_idx<<1]) >> 15;
          ((int16_t*)txdataF)[((l*frame_parms.ofdm_symbol_size + k)<<1) + 1] = (amp * mod_dci[(dci_idx<<1) + 1]) >> 15;
#ifdef DEBUG_DCI
  printf("l %d position %d => (%d,%d)\n",l,k,((int16_t*)txdataF)[(l*frame_parms.ofdm_symbol_size + k)<<1] ,
  ((int16_t*)txdataF)[((l*frame_parms.ofdm_symbol_size + k)<<1)+1]);
#endif
          dci_idx++;
        }
        k++;
        if (k >= frame_parms.ofdm_symbol_size)
          k -= frame_parms.ofdm_symbol_size;
      }
    }

  return 0;
}