446 lines
16 KiB
C
446 lines
16 KiB
C
/*
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* Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The OpenAirInterface Software Alliance licenses this file to You under
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* the OAI Public License, Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.openairinterface.org/?page_id=698
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*-------------------------------------------------------------------------------
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* For more information about the OpenAirInterface (OAI) Software Alliance:
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* contact@openairinterface.org
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*/
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/*! \file PHY/NR_TRANSPORT/nr_pbch.c
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* \brief Top-level routines for generating the PBCH/BCH physical/transport channel V15.1 03/2018
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* \author Guy De Souza
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* \thanks Special Thanks to Son Dang for helpful contributions and testing
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* \date 2018
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* \version 0.1
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* \company Eurecom
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* \email: desouza@eurecom.fr
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* \note
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* \warning
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*/
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#include "PHY/defs_gNB.h"
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#include "PHY/NR_TRANSPORT/nr_transport_proto.h"
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#include "PHY/sse_intrin.h"
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#include "executables/softmodem-common.h"
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#include "openair1/PHY/NR_REFSIG/nr_refsig_common.h"
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#include "openair1/PHY/NR_REFSIG/nr_mod_table.h"
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#include "openair1/PHY/TOOLS/tools_defs.h"
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//#define DEBUG_PBCH
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//#define DEBUG_PBCH_ENCODING
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//#define DEBUG_PBCH_DMRS
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const uint8_t nr_pbch_payload_interleaving_pattern[32] = {16, 23, 18, 17, 8, 30, 10, 6, 24, 7, 0, 5, 3, 2, 1, 4,
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9, 11, 12, 13, 14, 15, 19, 20, 21, 22, 25, 26, 27, 28, 29, 31
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};
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void nr_generate_pbch_dmrs(uint32_t *gold_pbch_dmrs,
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c16_t *txdataF,
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int16_t amp,
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uint8_t ssb_start_symbol,
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nfapi_nr_config_request_scf_t *config,
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NR_DL_FRAME_PARMS *frame_parms)
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{
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int k,l;
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//int16_t a;
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c16_t mod_dmrs[NR_PBCH_DMRS_LENGTH];
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uint8_t idx=0;
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uint8_t nushift = config->cell_config.phy_cell_id.value &3;
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LOG_D(PHY, "PBCH DMRS mapping started at symbol %d shift %d\n", ssb_start_symbol+1, nushift);
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/// QPSK modulation
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for (int m=0; m<NR_PBCH_DMRS_LENGTH; m++) {
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idx = (((gold_pbch_dmrs[(m<<1)>>5])>>((m<<1)&0x1f))&3);
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mod_dmrs[m] = nr_qpsk_mod_table[idx];
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#ifdef DEBUG_PBCH_DMRS
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printf("m %d idx %d gold seq %u b0-b1 %d-%d mod_dmrs %d %d\n",
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m,
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idx,
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gold_pbch_dmrs[(m << 1) >> 5],
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(((gold_pbch_dmrs[(m << 1) >> 5]) >> ((m << 1) & 0x1f)) & 1),
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(((gold_pbch_dmrs[((m << 1) + 1) >> 5]) >> (((m << 1) + 1) & 0x1f)) & 1),
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mod_dmrs[m].r,
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mod_dmrs[m].i);
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#endif
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}
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/// Resource mapping
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// PBCH DMRS are mapped within the SSB block on every fourth subcarrier starting from nushift of symbols 1, 2, 3
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///symbol 1 [0+nushift:4:236+nushift] -- 60 mod symbols
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k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
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l = ssb_start_symbol + 1;
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for (int m = 0; m < 60; m++) {
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#ifdef DEBUG_PBCH_DMRS
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printf("m %d at k %d of l %d\n", m, k, l);
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#endif
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txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_dmrs[m], amp, 15);
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k+=4;
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if (k >= frame_parms->ofdm_symbol_size)
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k-=frame_parms->ofdm_symbol_size;
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}
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///symbol 2 [0+u:4:44+nushift ; 192+nu:4:236+nushift] -- 24 mod symbols
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k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
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l++;
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for (int m = 60; m < 84; m++) {
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#ifdef DEBUG_PBCH_DMRS
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printf("m %d at k %d of l %d\n", m, k, l);
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#endif
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txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_dmrs[m], amp, 15);
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#ifdef DEBUG_PBCH_DMRS
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printf("(%d,%d)\n",
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((int16_t *)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1],
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((int16_t *)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1)+1]);
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#endif
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k+=(m==71)?148:4; // Jump from 44+nu to 192+nu
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if (k >= frame_parms->ofdm_symbol_size)
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k-=frame_parms->ofdm_symbol_size;
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}
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///symbol 3 [0+nushift:4:236+nushift] -- 60 mod symbols
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k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + nushift;
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l++;
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for (int m = 84; m < NR_PBCH_DMRS_LENGTH; m++) {
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#ifdef DEBUG_PBCH_DMRS
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printf("m %d at k %d of l %d\n", m, k, l);
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#endif
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txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_dmrs[m], amp, 15);
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k+=4;
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if (k >= frame_parms->ofdm_symbol_size)
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k-=frame_parms->ofdm_symbol_size;
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}
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#ifdef DEBUG_PBCH_DMRS
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write_output("txdataF_pbch_dmrs.m", "txdataF_pbch_dmrs", txdataF[0], frame_parms->samples_per_frame_wCP>>1, 1, 1);
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#endif
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}
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typedef struct {
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int len;
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int goldIdx;
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int offset;
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} NR_PBCH_scramb_info_t;
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static NR_PBCH_scramb_info_t get_scrambling_info(uint8_t nushift,
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uint16_t M,
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uint16_t length)
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{
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NR_PBCH_scramb_info_t info;
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info.len = (nushift * M + 31) / 32 + (length + 31) / 32;
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// The Gold sequence is shifted by nushift* M, so we skip (nushift*M /32) double words
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info.goldIdx = (nushift * M + 31) / 32 - 1;
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// Scrambling is now done with offset (nushift*M)%32
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info.offset = (nushift * M) & 0x1f;
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return info;
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}
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static void nr_pbch_encoded_scrambling(uint32_t *pbch_e,
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uint32_t Nid,
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uint8_t nushift,
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uint16_t M,
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uint16_t length)
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{
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NR_PBCH_scramb_info_t info = get_scrambling_info(nushift, M, length);
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uint32_t *s = gold_cache(Nid, info.len);
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int goldIdx = info.goldIdx;
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#ifdef DEBUG_PBCH_ENCODING
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printf("Scrambling params: nushift %d M %d length %d offset %d\n", nushift, M, length, info.offset);
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#endif
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#ifdef DEBUG_PBCH_ENCODING
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printf("s: %04x\t", s);
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#endif
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for (int i = 0; i < length; ++i) {
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if (((i + info.offset) & 0x1f) == 0)
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goldIdx++;
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pbch_e[i >> 5] ^= (((s[goldIdx] >> ((i + info.offset) & 0x1f)) & 1) << (i & 0x1f));
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}
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}
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static uint32_t nr_pbch_scrambling(uint32_t pbch_a_interleaved,
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uint32_t Nid,
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uint8_t nushift,
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uint16_t M,
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uint16_t length,
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uint32_t unscrambling_mask)
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{
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uint32_t pbch_a_prime = 0;
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int k = 0;
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NR_PBCH_scramb_info_t info = get_scrambling_info(nushift, M, length);
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uint32_t *s = gold_cache(Nid, info.len);
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#ifdef DEBUG_PBCH_ENCODING
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printf("Scrambling params: nushift %d M %d length %d offset %d\n", nushift, M, length, info.offset);
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#endif
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#ifdef DEBUG_PBCH_ENCODING
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printf("s: %04x\t", s);
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#endif
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int goldIdx = info.goldIdx;
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for (int i = 0; i < length; ++i) {
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if ((unscrambling_mask >> i) & 1)
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pbch_a_prime ^= ((pbch_a_interleaved >> i) & 1) << i;
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else {
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if (((k + info.offset) & 0x1f) == 0)
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goldIdx++;
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pbch_a_prime ^= (((pbch_a_interleaved >> i) & 1) ^ ((s[goldIdx] >> ((k + info.offset) & 0x1f)) & 1)) << i;
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k++; /// k increase only when payload bit is not special bit
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}
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}
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return pbch_a_prime;
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}
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void nr_init_pbch_interleaver(uint8_t *interleaver)
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{
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uint8_t j_sfn = 0, j_hrf = 10, j_ssb = 11, j_other = 14;
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memset((void *)interleaver,0, NR_POLAR_PBCH_PAYLOAD_BITS);
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for (int i = 0; i < NR_POLAR_PBCH_PAYLOAD_BITS; i++)
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if (!i) // choice bit:1
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*(interleaver + i) = *(nr_pbch_payload_interleaving_pattern + j_other++);
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else if (i < 7) //Sfn bits:6
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*(interleaver + i) = *(nr_pbch_payload_interleaving_pattern + j_sfn++);
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else if (i < 24) // other:17
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*(interleaver + i) = *(nr_pbch_payload_interleaving_pattern + j_other++);
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else if (i < 28) // Sfn:4
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*(interleaver + i) = *(nr_pbch_payload_interleaving_pattern + j_sfn++);
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else if (i == 28) // Hrf bit:1
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*(interleaver + i) = *(nr_pbch_payload_interleaving_pattern + j_hrf);
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else // Ssb bits:3
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*(interleaver + i) = *(nr_pbch_payload_interleaving_pattern + j_ssb++);
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}
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uint32_t nr_pbch_extra_byte_generation(int sfn, int n_hf, int ssb_index, int ssb_sc_offset, int Lmax)
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{
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uint32_t extra_byte = 0;
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// Extra byte generation
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for (int i = 0; i < 4; i++)
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extra_byte |= ((sfn >> (3 - i)) & 1) << i; // resp. 4th, 3rd, 2nd ans 1st lsb of sfn
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extra_byte |= n_hf << 4; // half frame index bit
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if (Lmax == 64)
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for (int i = 0; i < 3; i++)
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extra_byte |= (uint32_t)((ssb_index >> (5 - i)) & 1) << (5 + i); // resp. 6th, 5th and 4th bits of ssb_index
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else
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extra_byte |= ((ssb_sc_offset >> 4) & 1) << 5; //MSB of k_SSB (bit index 4)
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return extra_byte;
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}
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void nr_generate_pbch(PHY_VARS_gNB *gNB,
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const nfapi_nr_dl_tti_ssb_pdu *ssb_pdu,
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c16_t *txdataF,
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uint8_t ssb_start_symbol,
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uint8_t n_hf,
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int sfn,
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nfapi_nr_config_request_scf_t *config,
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NR_DL_FRAME_PARMS *frame_parms)
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{
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LOG_D(PHY, "PBCH generation started\n");
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///Payload generation
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uint8_t ssb_index = ssb_pdu->ssb_pdu_rel15.SsbBlockIndex;
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const uint8_t *pbch_pdu = (const uint8_t*)&ssb_pdu->ssb_pdu_rel15.bchPayload;
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uint8_t Lmax = frame_parms->Lmax;
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uint32_t pbch_a = 0;
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for (int i = 0; i < NR_PBCH_PDU_BITS; i++)
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pbch_a |= ((pbch_pdu[i >> 3] >> (7 - (i & 7))) & 1) << i;
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// NSA to signal no coreset0
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const int ssb_sc_offset = IS_SA_MODE(get_softmodem_params()) ? config->ssb_table.ssb_subcarrier_offset.value : 31;
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#ifdef DEBUG_PBCH_ENCODING
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for (int i = 0; i < 3; i++)
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printf("pbch_pdu[%d]: 0x%02x\n", i, pbch_pdu[i]);
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printf("PBCH payload = 0x%08x\n", pbch_a);
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#endif
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uint32_t extra_byte = nr_pbch_extra_byte_generation(sfn, n_hf, ssb_index, ssb_sc_offset, Lmax);
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pbch_a |= extra_byte << 24;
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LOG_D(PHY,"After extra byte: pbch_a = 0x%08x\n", pbch_a);
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// Payload interleaving
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uint32_t pbch_a_interleaved = 0;
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uint8_t *interleaver = gNB->nr_pbch_interleaver;
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for (int i = 0; i < NR_POLAR_PBCH_PAYLOAD_BITS; i++) {
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pbch_a_interleaved |= ((pbch_a >> i) & 1) << (*(interleaver + i));
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#ifdef DEBUG_PBCH_ENCODING
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printf("i %d out 0x%08x ilv %d (in>>i)&1) %d\n", i, pbch_a_interleaved, *(interleaver+i), (pbch_a >> i) & 1);
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#endif
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}
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#ifdef DEBUG_PBCH_ENCODING
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printf("Interleaving:\n");
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printf("pbch_a_interleaved: 0x%08x\n", pbch_a_interleaved);
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#endif
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// Scrambling
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uint32_t unscrambling_mask = (Lmax == 64) ? 0x100006D : 0x1000041;
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uint16_t M = (Lmax == 64)? (NR_POLAR_PBCH_PAYLOAD_BITS - 6) : (NR_POLAR_PBCH_PAYLOAD_BITS - 3);
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uint8_t nushift = (((sfn >> 2) & 1) << 1) ^ ((sfn >> 1) & 1);
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uint32_t pbch_a_prime = nr_pbch_scrambling(pbch_a_interleaved,
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(uint32_t)config->cell_config.phy_cell_id.value,
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nushift,
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M,
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NR_POLAR_PBCH_PAYLOAD_BITS,
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unscrambling_mask);
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#ifdef DEBUG_PBCH_ENCODING
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printf("Payload scrambling: nushift %d M %d sfn3 %d sfn2 %d\n", nushift, M, (sfn >> 2) & 1, (sfn >> 1) & 1);
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printf("pbch_a_prime: 0x%08x\n", pbch_a_prime);
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#endif
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// Encoder reversal
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uint64_t a_reversed = reverse_bits((uint64_t)pbch_a_prime, NR_POLAR_PBCH_PAYLOAD_BITS);
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uint32_t pbch_e[NR_POLAR_PBCH_E_DWORD];
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/// CRC, coding and rate matching
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polar_encoder_fast(&a_reversed,
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pbch_e,
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0,
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0,
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NR_POLAR_PBCH_MESSAGE_TYPE,
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NR_POLAR_PBCH_PAYLOAD_BITS,
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NR_POLAR_PBCH_AGGREGATION_LEVEL);
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#ifdef DEBUG_PBCH_ENCODING
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printf("Channel coding:\n");
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for (int i = 0; i < NR_POLAR_PBCH_E_DWORD; i++)
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printf("pbch_e[%d]: 0x%08x\t", i, pbch_e[i]);
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printf("\n");
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#endif
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/// Scrambling
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M = NR_POLAR_PBCH_E;
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nushift = (Lmax == 4) ? ssb_index & 3 : ssb_index & 7;
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nr_pbch_encoded_scrambling(pbch_e,
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(uint32_t)config->cell_config.phy_cell_id.value,
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nushift,
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M,
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NR_POLAR_PBCH_E);
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#ifdef DEBUG_PBCH_ENCODING
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printf("Scrambling:\n");
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for (int i = 0; i < NR_POLAR_PBCH_E_DWORD; i++)
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printf("pbch_e[%d]: 0x%08x\t", i, pbch_e[i]);
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printf("\n");
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#endif
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c16_t mod_pbch_e[NR_POLAR_PBCH_E / 2];
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/// QPSK modulation
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for (int i=0; i<NR_POLAR_PBCH_E>>1; i++) {
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int idx = ((pbch_e[(i << 1) >> 5] >> ((i << 1) & 0x1f)) & 3);
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mod_pbch_e[i] = nr_qpsk_mod_table[idx];
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#ifdef DEBUG_PBCH
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printf("i %d idx %d mod_pbch %d %d\n", i, idx, mod_pbch_e[i].r, mod_pbch_e[i].i);
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#endif
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}
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/// Resource mapping
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nushift = config->cell_config.phy_cell_id.value &3;
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// PBCH modulated symbols are mapped within the SSB block on symbols 1, 2, 3 excluding the subcarriers used for the PBCH DMRS
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///symbol 1 [0:239] -- 180 mod symbols
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int k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier;
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int l = ssb_start_symbol + 1;
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int m = 0;
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int16_t amp = gNB->TX_AMP;
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for (int ssb_sc_idx = 0; ssb_sc_idx < 240; ssb_sc_idx++) {
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if ((ssb_sc_idx&3) == nushift) { //skip DMRS
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k++;
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continue;
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} else {
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#ifdef DEBUG_PBCH
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printf("m %d ssb_sc_idx %d at k %d of l %d\n", m, ssb_sc_idx, k, l);
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#endif
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txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_pbch_e[m], amp, 15);
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k++;
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m++;
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}
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if (k >= frame_parms->ofdm_symbol_size)
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k-=frame_parms->ofdm_symbol_size;
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}
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///symbol 2 [0:47 ; 192:239] -- 72 mod symbols
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k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier;
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l++;
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m=180;
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for (int ssb_sc_idx = 0; ssb_sc_idx < 48; ssb_sc_idx++) {
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if ((ssb_sc_idx&3) == nushift) {
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k++;
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continue;
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} else {
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#ifdef DEBUG_PBCH
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printf("m %d ssb_sc_idx %d at k %d of l %d\n", m, ssb_sc_idx, k, l);
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#endif
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txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_pbch_e[m], amp, 15);
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k++;
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m++;
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}
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if (k >= frame_parms->ofdm_symbol_size)
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k-=frame_parms->ofdm_symbol_size;
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}
|
|
|
|
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
|
|
txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_pbch_e[m], amp, 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
|
|
txdataF[l * frame_parms->ofdm_symbol_size + k] = c16mulRealShift(mod_pbch_e[m], amp, 15);
|
|
k++;
|
|
m++;
|
|
}
|
|
|
|
|
|
if (k >= frame_parms->ofdm_symbol_size)
|
|
k-=frame_parms->ofdm_symbol_size;
|
|
}
|
|
}
|