/* * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more * contributor license agreements. See the NOTICE file distributed with * 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, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. *------------------------------------------------------------------------------- * For more information about the OpenAirInterface (OAI) Software Alliance: * contact@openairinterface.org */ /*! \file PHY/NR_TRANSPORT/nr_pbch.c * \brief Top-level routines for generating the PBCH/BCH physical/transport channel V15.1 03/2018 * \author Guy De Souza * \thanks Special Thanks to Son Dang for helpful contributions and testing * \date 2018 * \version 0.1 * \company Eurecom * \email: desouza@eurecom.fr * \note * \warning */ #include "PHY/defs_gNB.h" #include "PHY/NR_TRANSPORT/nr_transport.h" #include "PHY/LTE_REFSIG/lte_refsig.h" #include "PHY/sse_intrin.h" //#define DEBUG_PBCH //#define DEBUG_PBCH_ENCODING //#define DEBUG_PBCH_DMRS #include "PHY/NR_REFSIG/nr_mod_table.h" uint8_t nr_pbch_payload_interleaving_pattern[32] = {16, 23, 18, 17, 8, 30, 10, 6, 24, 7, 0, 5, 3, 2, 1, 4, 9, 11, 12, 13, 14, 15, 19, 20, 21, 22, 25, 26, 27, 28, 29, 31}; int nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs, int32_t *txdataF, int16_t amp, uint8_t ssb_start_symbol, nfapi_nr_config_request_t* config, NR_DL_FRAME_PARMS *frame_parms) { int k,l; int16_t a; int16_t mod_dmrs[NR_PBCH_DMRS_LENGTH<<1]; uint8_t idx=0; uint8_t nushift = config->sch_config.physical_cell_id.value &3; LOG_D(PHY, "PBCH DMRS mapping started at symbol %d shift %d\n", ssb_start_symbol+1, nushift); /// QPSK modulation for (int m=0; m<NR_PBCH_DMRS_LENGTH; m++) { idx = ((((gold_pbch_dmrs[(m<<1)>>5])>>((m<<1)&0x1f))&1)<<1) ^ (((gold_pbch_dmrs[((m<<1)+1)>>5])>>(((m<<1)+1)&0x1f))&1); mod_dmrs[m<<1] = nr_mod_table[(NR_MOD_TABLE_QPSK_OFFSET + idx)<<1]; mod_dmrs[(m<<1)+1] = nr_mod_table[((NR_MOD_TABLE_QPSK_OFFSET + idx)<<1) + 1]; #ifdef DEBUG_PBCH_DMRS printf("m %d idx %d gold seq %d b0-b1 %d-%d mod_dmrs %d %d\n", m, idx, gold_pbch_dmrs[(m<<1)>>5], (((gold_pbch_dmrs[(m<<1)>>5])>>((m<<1)&0x1f))&1), (((gold_pbch_dmrs[((m<<1)+1)>>5])>>(((m<<1)+1)&0x1f))&1), mod_dmrs[(m<<1)], mod_dmrs[(m<<1)+1]); #endif } /// Resource mapping // PBCH DMRS are mapped within the SSB block on every fourth subcarrier starting from nushift of symbols 1, 2, 3 ///symbol 1 [0+nushift:4:236+nushift] -- 60 mod symbols k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift; l = ssb_start_symbol + 1; for (int m = 0; m < 60; m++) { #ifdef DEBUG_PBCH_DMRS printf("m %d at k %d of l %d\n", m, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_dmrs[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_dmrs[(m<<1) + 1]) >> 15; #ifdef DEBUG_PBCH_DMRS printf("(%d,%d)\n", ((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; } ///symbol 2 [0+u:4:44+nushift ; 192+nu:4:236+nushift] -- 24 mod symbols k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift; l++; for (int m = 60; m < 84; m++) { #ifdef DEBUG_PBCH_DMRS printf("m %d at k %d of l %d\n", m, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_dmrs[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_dmrs[(m<<1) + 1]) >> 15; #ifdef DEBUG_PBCH_DMRS printf("(%d,%d)\n", ((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+=(m==71)?148:4; // Jump from 44+nu to 192+nu if (k >= frame_parms->ofdm_symbol_size) k-=frame_parms->ofdm_symbol_size; } ///symbol 3 [0+nushift:4:236+nushift] -- 60 mod symbols k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift; l++; for (int m = 84; m < NR_PBCH_DMRS_LENGTH; m++) { #ifdef DEBUG_PBCH_DMRS printf("m %d at k %d of l %d\n", m, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_dmrs[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_dmrs[(m<<1) + 1]) >> 15; #ifdef DEBUG_PBCH_DMRS printf("(%d,%d)\n", ((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; } #ifdef DEBUG_PBCH_DMRS write_output("txdataF_pbch_dmrs.m", "txdataF_pbch_dmrs", txdataF[0], frame_parms->samples_per_frame_wCP>>1, 1, 1); #endif return 0; } void nr_pbch_scrambling(NR_gNB_PBCH *pbch, uint32_t Nid, uint8_t nushift, uint16_t M, uint16_t length, uint8_t encoded, uint32_t unscrambling_mask) { uint8_t reset, offset; uint32_t x1, x2, s=0; uint32_t *pbch_e = pbch->pbch_e; reset = 1; // x1 is set in lte_gold_generic x2 = Nid; // The Gold sequence is shifted by nushift* M, so we skip (nushift*M /32) double words for (int i=0; i<(uint16_t)ceil(((float)nushift*M)/32); i++) { s = lte_gold_generic(&x1, &x2, reset); reset = 0; } // Scrambling is now done with offset (nushift*M)%32 offset = (nushift*M)&0x1f; #ifdef DEBUG_PBCH_ENCODING printf("Scrambling params: nushift %d M %d length %d encoded %d offset %d\n", nushift, M, length, encoded, offset); #endif #ifdef DEBUG_PBCH_ENCODING printf("s: %04x\t", s); #endif int k = 0; if (!encoded) { /// 1st Scrambling for (int i = 0; i < length; ++i) { if ((unscrambling_mask>>i)&1) pbch->pbch_a_prime ^= ((pbch->pbch_a_interleaved>>i)&1)<<i; else { if (((k+offset)&0x1f)==0) { s = lte_gold_generic(&x1, &x2, reset); reset = 0; } pbch->pbch_a_prime ^= (((pbch->pbch_a_interleaved>>i)&1) ^ ((s>>((k+offset)&0x1f))&1))<<i; k++; /// k increase only when payload bit is not special bit } } } else { /// 2nd Scrambling for (int i = 0; i < length; ++i) { if (((i+offset)&0x1f)==0) { s = lte_gold_generic(&x1, &x2, reset); reset = 0; } pbch_e[i>>5] ^= (((s>>((i+offset)&0x1f))&1)<<(i&0x1f)); } } } void nr_init_pbch_interleaver(uint8_t *interleaver) { uint8_t j_sfn=0, j_hrf=10, j_ssb=11, j_other=14; memset((void*)interleaver,0, NR_POLAR_PBCH_PAYLOAD_BITS); for (uint8_t i=0; i<NR_POLAR_PBCH_PAYLOAD_BITS; i++) if (!i) // choice bit:1 *(interleaver+i) = *(nr_pbch_payload_interleaving_pattern+j_other++); else if (i<7) //Sfn bits:6 *(interleaver+i) = *(nr_pbch_payload_interleaving_pattern+j_sfn++); else if (i<24) // other:17 *(interleaver+i) = *(nr_pbch_payload_interleaving_pattern+j_other++); else if (i<28) // Sfn:4 *(interleaver+i) = *(nr_pbch_payload_interleaving_pattern+j_sfn++); else if (i==28) // Hrf bit:1 *(interleaver+i) = *(nr_pbch_payload_interleaving_pattern+j_hrf); else // Ssb bits:3 *(interleaver+i) = *(nr_pbch_payload_interleaving_pattern+j_ssb++); } int nr_generate_pbch(NR_gNB_PBCH *pbch, t_nrPolar_paramsPtr polar_params, uint8_t *pbch_pdu, uint8_t *interleaver, int32_t *txdataF, int16_t amp, uint8_t ssb_start_symbol, uint8_t n_hf, uint8_t Lmax, uint8_t ssb_index, int sfn, nfapi_nr_config_request_t* config, NR_DL_FRAME_PARMS *frame_parms) { int k,l,m; int16_t a; int16_t mod_pbch_e[NR_POLAR_PBCH_E]; uint8_t idx=0; uint16_t M; uint8_t nushift; uint32_t unscrambling_mask; LOG_I(PHY, "PBCH generation started\n"); ///Payload generation memset((void*)pbch, 0, sizeof(NR_gNB_PBCH)); pbch->pbch_a=0; for (int i=0; i<NR_PBCH_PDU_BITS; i++) pbch->pbch_a |= ((pbch_pdu[2-(i>>3)]>>(7-(i&7)))&1)<<i; #ifdef DEBUG_PBCH_ENCODING for (int i=0; i<3; i++) printf("pbch_pdu[%d]: 0x%02x\n", i, pbch_pdu[i]); printf("PBCH payload = 0x%08x\n",pbch->pbch_a); #endif // Extra byte generation for (int i=0; i<4; i++) pbch->pbch_a |= ((sfn>>(3-i))&1)<<(24+i); // resp. 4th, 3rd, 2nd ans 1st lsb of sfn pbch->pbch_a |= n_hf<<28; // half frame index bit if (Lmax == 64) for (int i=0; i<3; i++) pbch->pbch_a |= ((ssb_index>>(5-i))&1)<<(29+i); // resp. 6th, 5th and 4th bits of ssb_index else pbch->pbch_a |= ((config->sch_config.ssb_subcarrier_offset.value>>4)&1)<<29; //MSB of k_SSB (bit index 4) LOG_I(PHY,"After extra byte: pbch_a = 0x%08x\n",pbch->pbch_a); // Payload interleaving for (int i=0; i<NR_POLAR_PBCH_PAYLOAD_BITS; i++) { pbch->pbch_a_interleaved |= ((pbch->pbch_a>>i)&1)<<(*(interleaver+i)); #ifdef DEBUG_PBCH_ENCODING printf("i %d out 0x%08x ilv %d (in>>i)&1) %d\n", i, pbch->pbch_a_interleaved, *(interleaver+i), (pbch->pbch_a>>i)&1); #endif } #ifdef DEBUG_PBCH_ENCODING printf("Interleaving:\n"); printf("pbch_a_interleaved: 0x%08x\n", pbch->pbch_a_interleaved); #endif // Scrambling unscrambling_mask = (Lmax ==64)? 0x100006D:0x1000041; M = (Lmax == 64)? (NR_POLAR_PBCH_PAYLOAD_BITS - 6) : (NR_POLAR_PBCH_PAYLOAD_BITS - 3); nushift = (((sfn>>2)&1)<<1) ^ ((sfn>>1)&1); pbch->pbch_a_prime = 0; nr_pbch_scrambling(pbch, (uint32_t)config->sch_config.physical_cell_id.value, nushift, M, NR_POLAR_PBCH_PAYLOAD_BITS, 0, unscrambling_mask); #ifdef DEBUG_PBCH_ENCODING printf("Payload scrambling: nushift %d M %d sfn3 %d sfn2 %d\n", nushift, M, (sfn>>2)&1, (sfn>>1)&1); printf("pbch_a_prime: 0x%08x\n", pbch->pbch_a_prime); #endif /// CRC, coding and rate matching polar_encoder_fast (&pbch->pbch_a_prime, (uint32_t*)pbch->pbch_e, 0, polar_params); #ifdef DEBUG_PBCH_ENCODING printf("Channel coding:\n"); for (int i=0; i<NR_POLAR_PBCH_E_DWORD; i++) printf("pbch_e[%d]: 0x%08x\t", i, pbch->pbch_e[i]); printf("\n"); #endif /// Scrambling M = NR_POLAR_PBCH_E; nushift = (Lmax==4)? ssb_index&3 : ssb_index&7; nr_pbch_scrambling(pbch, (uint32_t)config->sch_config.physical_cell_id.value, nushift, M, NR_POLAR_PBCH_E, 1, 0); #ifdef DEBUG_PBCH_ENCODING printf("Scrambling:\n"); for (int i=0; i<NR_POLAR_PBCH_E_DWORD; i++) printf("pbch_e[%d]: 0x%08x\t", i, pbch->pbch_e[i]); printf("\n"); #endif /// QPSK modulation for (int i=0; i<NR_POLAR_PBCH_E>>1; i++){ idx = (((pbch->pbch_e[(i<<1)>>5]>>((i<<1)&0x1f))&1)<<1) ^ ((pbch->pbch_e[((i<<1)+1)>>5]>>(((i<<1)+1)&0x1f))&1); mod_pbch_e[i<<1] = nr_mod_table[(NR_MOD_TABLE_QPSK_OFFSET + idx)<<1]; mod_pbch_e[(i<<1)+1] = nr_mod_table[((NR_MOD_TABLE_QPSK_OFFSET + idx)<<1)+1]; #ifdef DEBUG_PBCH printf("i %d idx %d mod_pbch %d %d\n", i, idx, mod_pbch_e[2*i], mod_pbch_e[2*i+1]); #endif } /// Resource mapping nushift = config->sch_config.physical_cell_id.value &3; // PBCH modulated symbols are mapped within the SSB block on symbols 1, 2, 3 excluding the subcarriers used for the PBCH DMRS ///symbol 1 [0:239] -- 180 mod symbols k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier; l = ssb_start_symbol + 1; m = 0; for (int ssb_sc_idx = 0; ssb_sc_idx < 240; ssb_sc_idx++) { if ((ssb_sc_idx&3) == nushift) { //skip DMRS k++; continue; } else { #ifdef DEBUG_PBCH printf("m %d ssb_sc_idx %d at k %d of l %d\n", m, ssb_sc_idx, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_pbch_e[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_pbch_e[(m<<1) + 1]) >> 15; k++; m++; } if (k >= frame_parms->ofdm_symbol_size) k-=frame_parms->ofdm_symbol_size; } ///symbol 2 [0:47 ; 192:239] -- 72 mod symbols k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier; l++; m=180; for (int ssb_sc_idx = 0; ssb_sc_idx < 48; ssb_sc_idx++) { if ((ssb_sc_idx&3) == nushift) { k++; continue; } else { #ifdef DEBUG_PBCH printf("m %d ssb_sc_idx %d at k %d of l %d\n", m, ssb_sc_idx, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_pbch_e[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_pbch_e[(m<<1) + 1]) >> 15; k++; m++; } if (k >= frame_parms->ofdm_symbol_size) k-=frame_parms->ofdm_symbol_size; } k += 144; if (k >= frame_parms->ofdm_symbol_size) k-=frame_parms->ofdm_symbol_size; m=216; for (int ssb_sc_idx = 192; ssb_sc_idx < 240; ssb_sc_idx++) { if ((ssb_sc_idx&3) == nushift) { k++; continue; } else { #ifdef DEBUG_PBCH printf("m %d ssb_sc_idx %d at k %d of l %d\n", m, ssb_sc_idx, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_pbch_e[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_pbch_e[(m<<1) + 1]) >> 15; k++; m++; } if (k >= frame_parms->ofdm_symbol_size) k-=frame_parms->ofdm_symbol_size; } ///symbol 3 [0:239] -- 180 mod symbols k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier; l++; m=252; for (int ssb_sc_idx = 0; ssb_sc_idx < 240; ssb_sc_idx++) { if ((ssb_sc_idx&3) == nushift) { k++; continue; } else { #ifdef DEBUG_PBCH printf("m %d ssb_sc_idx %d at k %d of l %d\n", m, ssb_sc_idx, k, l); #endif ((int16_t*)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_pbch_e[m<<1]) >> 15; ((int16_t*)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_pbch_e[(m<<1) + 1]) >> 15; k++; m++; } if (k >= frame_parms->ofdm_symbol_size) k-=frame_parms->ofdm_symbol_size; } #ifdef DEBUG_PBCH write_output("txdataF_pbch.m", "txdataF_pbch", txdataF[0], frame_parms->samples_per_frame_wCP>>1, 1, 1); #endif return 0; }