common_utils.cpp

Go to the documentation of this file.

/*
 * Copyright 2020 Telecom Paris

   Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0

   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.
 */

#include <cmath>
#include "common_utils.h"


void free5GRAN::utils::common_utils::parse_mib(int *mib_bits, free5GRAN::mib &mib_object) {
    /*
     * Getting MIB informations
    */
    // Recovering SFN from BCH payload
    int sfn_array[10] = {mib_bits[1], mib_bits[2], mib_bits[3], mib_bits[4], mib_bits[5], mib_bits[6],mib_bits[24], mib_bits[25], mib_bits[26], mib_bits[27]};
    mib_object.sfn = 0;
    for (int i = 0 ; i < 10; i ++){
        mib_object.sfn += sfn_array[i] * pow(2, 10 - 1 - i);
    }

    int available_scs[2] = {15, 30};
    // Recovering PDCCH config identifier
    int pdcch_config_array[8];
    for (int i = 0 ; i < 8; i ++){
        pdcch_config_array[i] = mib_bits[13 + i];
    }
    mib_object.pdcch_config = 0;
    for (int i = 0 ; i < 8; i ++){
        mib_object.pdcch_config += pdcch_config_array[i] * pow(2, 8 - 1 - i);
    }
    // Recovering cell barred information
    mib_object.cell_barred = mib_bits[21];
    mib_object.scs = available_scs[mib_bits[7]];

    int k_ssb_array[5] = {mib_bits[29], mib_bits[8], mib_bits[9], mib_bits[10], mib_bits[11]};
    mib_object.k_ssb = 0;
    for (int i = 0 ; i < 5; i ++){
        mib_object.k_ssb += k_ssb_array[i] * pow(2, 5 - 1 - i);
    }
    mib_object.dmrs_type_a_position = 2 + mib_bits[12];
    mib_object.intra_freq_reselection = mib_bits[22];
}

/*
 * Scrambling implementation: output = (input + c_seq)[2]
 */
void free5GRAN::utils::common_utils::scramble(int *input_bits, int *c_seq, int *output_bits, int length, int offset) {
    for (int i = 0; i < length; i ++){
        output_bits[i] = (input_bits[i] + c_seq[i + offset]) % 2;
    }
}

void free5GRAN::utils::common_utils::scramble(double *input_bits, int *c_seq, double *output_bits, int length, int offset) {
    for (int i = 0; i < length; i ++){
        output_bits[i] = input_bits[i] * c_seq[i + offset];
    }
}