mirror of https://github.com/pvnis/srsRAN_4G.git
Rearanged PDCCH NR functions structures
Xavier Arteaga
4 years ago
committed by
Xavier Arteaga
parent
452eb2dbbf
commit
775692f461
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/*
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* Copyright 2013-2020 Software Radio Systems Limited
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*
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* This file is part of srsLTE.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE 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 Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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/******************************************************************************
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* File: pdcch.h
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*
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* Description: Physical downlink control channel.
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*
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* Reference: 3GPP TS 36.211 version 10.0.0 Release 10 Sec. 6.8
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*****************************************************************************/
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#ifndef SRSLTE_PDCCH_NR_H
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#define SRSLTE_PDCCH_NR_H
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#include "srslte/config.h"
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#include "srslte/phy/common/phy_common_nr.h"
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/**
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* @brief Function for generating NR PDCCH candidate locations n_cce for a given CORESET, search space, aggregation
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* level and slot.
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*
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* @see srslte_pdcch_ue_locations_ncce
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* @see srslte_pdcch_common_locations_ncce
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*
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* @param coreset is the coreset configuration provided from higher layers
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* @param search_space is the Search Space configuration provided from higher layers
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* @param RNTI UE temporal identifier, unused for common search spaces
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* @param aggregation_level aggregation level in logarithm range (0,1,2,3,4)
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* @param slot_idx Slot index within the radio frame
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* @param locations is the destination array with the possible candidate locations n_cce
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*/
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int srslte_pdcch_nr_locations_ncce(const srslte_coreset_t* coreset,
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const srslte_search_space_t* search_space,
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uint16_t rnti,
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uint32_t aggregation_level,
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uint32_t slot_idx,
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uint32_t locations[SRSLTE_SEARCH_SPACE_MAX_NOF_CANDIDATES]);
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#endif // SRSLTE_PDCCH_NR_H
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@ -0,0 +1,111 @@
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/*
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* Copyright 2013-2020 Software Radio Systems Limited
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*
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* This file is part of srsLTE.
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*
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* srsLTE is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* srsLTE 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 Affero General Public License for more details.
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*
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* A copy of the GNU Affero General Public License can be found in
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* the LICENSE file in the top-level directory of this distribution
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* and at http://www.gnu.org/licenses/.
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*
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*/
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#include "srslte/phy/phch/pdcch_nr.h"
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#include "srslte/phy/utils/debug.h"
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#include "srslte/phy/utils/vector.h"
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/**
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* @brief Recursive Y_p_n function
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*/
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static uint32_t srslte_pdcch_calculate_Y_p_n(uint32_t coreset_id, uint16_t rnti, int n)
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{
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static const uint32_t A_p[3] = {39827, 39829, 39839};
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const uint32_t D = 65537;
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if (n < 0) {
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return rnti;
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}
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return (A_p[coreset_id % 3] * srslte_pdcch_calculate_Y_p_n(coreset_id, rnti, n - 1)) % D;
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}
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/**
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* Calculates the Control Channnel Element As described in 3GPP 38.213 R15 10.1 UE procedure for determining physical
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* downlink control channel assignment
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*
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*/
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static int srslte_pdcch_nr_get_ncce(const srslte_coreset_t* coreset,
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const srslte_search_space_t* search_space,
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uint16_t rnti,
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uint32_t aggregation_level,
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uint32_t slot_idx,
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uint32_t candidate)
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{
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if (aggregation_level >= SRSLTE_SEARCH_SPACE_NOF_AGGREGATION_LEVELS) {
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ERROR("Invalid aggregation level %d;\n", aggregation_level);
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return SRSLTE_ERROR;
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}
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uint32_t L = 1U << aggregation_level; // Aggregation level
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uint32_t n_ci = 0; // Carrier indicator field
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uint32_t m = candidate; // Selected PDDCH candidate
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uint32_t M = search_space->nof_candidates[aggregation_level]; // Number of aggregation levels
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if (M == 0) {
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ERROR("Invalid number of candidates %d for aggregation level %d\n", M, aggregation_level);
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return SRSLTE_ERROR;
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}
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// Every REG is 1PRB wide and a CCE is 6 REG. So, the number of N_CCE is a sixth of the bandwidth times the number of
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// symbols
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uint32_t N_cce = srslte_coreset_get_bw(coreset) * coreset->duration / 6;
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if (N_cce < L) {
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ERROR("Error number of CCE %d is lower than the aggregation level %d\n", N_cce, L);
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return SRSLTE_ERROR;
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}
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// Calculate Y_p_n for UE search space only
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uint32_t Y_p_n = 0;
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if (search_space->type == srslte_search_space_type_ue) {
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Y_p_n = srslte_pdcch_calculate_Y_p_n(coreset->id, rnti, slot_idx);
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}
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return (int)(L * ((Y_p_n + (m * N_cce) / (L * M) + n_ci) % (N_cce / L)));
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}
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int srslte_pdcch_nr_locations_ncce(const srslte_coreset_t* coreset,
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const srslte_search_space_t* search_space,
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uint16_t rnti,
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uint32_t aggregation_level,
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uint32_t slot_idx,
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uint32_t locations[SRSLTE_SEARCH_SPACE_MAX_NOF_CANDIDATES])
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{
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if (coreset == NULL || search_space == NULL) {
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return SRSLTE_ERROR_INVALID_INPUTS;
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}
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uint32_t nof_candidates = search_space->nof_candidates[aggregation_level];
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nof_candidates = SRSLTE_MIN(nof_candidates, SRSLTE_SEARCH_SPACE_MAX_NOF_CANDIDATES);
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for (uint32_t candidate = 0; candidate < nof_candidates; candidate++) {
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int ret = srslte_pdcch_nr_get_ncce(coreset, search_space, rnti, aggregation_level, slot_idx, candidate);
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if (ret < SRSLTE_SUCCESS) {
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return ret;
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}
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locations[candidate] = ret;
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}
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return nof_candidates;
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}
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