sequence_generator.cpp

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/*
 * 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 "sequence_generator.h"
#include "../../variables/common_variables/common_variables.h"
#include <cmath>
#include <iostream>
using namespace std;

void free5GRAN::utils::sequence_generator::generate_pss_sequence(int n_id_2, int *output_sequence) {
    int x_seq[free5GRAN::SIZE_PSS_SSS_SIGNAL];
    for (int i = 0; i < free5GRAN::SIZE_PSS_SSS_SIGNAL; i++){
        if (i < 7){
            x_seq[i] = free5GRAN::PSS_BASE_SEQUENCE[i];
        } else {
            x_seq[i] = (x_seq[i - 3] + x_seq[i - 7]) % 2;
        }
    }
    for (int n = 0; n < free5GRAN::SIZE_PSS_SSS_SIGNAL; n++){
        int m = (n + 43 * n_id_2) % free5GRAN::SIZE_PSS_SSS_SIGNAL;
        output_sequence[n] = 1 - 2 * x_seq[m];
    }

}

void free5GRAN::utils::sequence_generator::generate_sss_sequence(int n_id_1, int n_id_2, int *output_sequence) {
    int m0, m1;
    int x0_seq[free5GRAN::SIZE_PSS_SSS_SIGNAL];
    int x1_seq[free5GRAN::SIZE_PSS_SSS_SIGNAL];
    for (int i = 0; i < free5GRAN::SIZE_PSS_SSS_SIGNAL; i++){
        if (i < 7){
            x0_seq[i] = free5GRAN::SSS_BASE_X0_SEQUENCE[i];
            x1_seq[i] = free5GRAN::SSS_BASE_X1_SEQUENCE[i];;
        } else {
            x0_seq[i] = (x0_seq[i - 3] + x0_seq[i - 7]) % 2;
            x1_seq[i] = (x1_seq[i - 6] + x1_seq[i - 7]) % 2;
        }
    }
    m0 = 15 * (n_id_1 / 112) + 5 * n_id_2;
    m1 = n_id_1 % 112;
    for (int n = 0; n < free5GRAN::SIZE_PSS_SSS_SIGNAL; n++){
        output_sequence[n] = (1 - 2 * x0_seq[(n + m0) % free5GRAN::SIZE_PSS_SSS_SIGNAL]) * (1 - 2 * x1_seq[(n + m1) % free5GRAN::SIZE_PSS_SSS_SIGNAL]);
    }
}

void free5GRAN::utils::sequence_generator::generate_pbch_dmrs_sequence(int pci, int i_bar_ssb, complex<float> *output_sequence) {
    int c_init = pow(2,11) * (i_bar_ssb + 1) * (pci / 4 + 1) + pow(2,6) * (i_bar_ssb + 1) + (pci % 4);
    int seq[2 * free5GRAN::SIZE_SSB_DMRS_SYMBOLS];
    generate_c_sequence(c_init, 2 * free5GRAN::SIZE_SSB_DMRS_SYMBOLS, seq, 0);
    for (int m = 0 ; m < free5GRAN::SIZE_SSB_DMRS_SYMBOLS; m++){
        output_sequence[m] = (float) (1 / sqrt(2)) * complex<float>(1 - 2 * seq[2 * m], 1 - 2 * seq[2 * m + 1]);
    }
}


void free5GRAN::utils::sequence_generator::generate_c_sequence(long c_init, int length, int *output_sequence, int demod_type) {
    int x1[1600 + length], x2[1600 + length], base_x2[32];

    for (int j = 0; j < 31; j ++){
        base_x2[j] = ((int) c_init / (int) pow(2,j)) % 2;
    }
    for (int n = 0; n < 1600 + length; n ++){
        if (n < 31){
            x1[n] = free5GRAN::DMRS_BASE_X1_SEQUENCE[n];
            x2[n] = base_x2[n];
        }else {
            x1[n] = (x1[n - 28] + x1[n - 31]) % 2;
            x2[n] = (x2[n - 28] + x2[n - 29] + x2[n - 30] + x2[n - 31]) % 2;
        }
    }
    for (int j = 0; j < length; j ++){
        output_sequence[j] = (x1[j + 1600] + x2[j + 1600]) % 2;
        if (demod_type == 1){
            output_sequence[j] = (output_sequence[j]==0) ? 1 : -1;
        }
    }

}

void free5GRAN::utils::sequence_generator::generate_pdcch_dmrs_sequence(int nid, int slot_number, int symbol_number, complex<float> *output_sequence, int size){
    long c_init = (long)(pow(2, 17) * (14 * slot_number + symbol_number + 1) * (2 * nid + 1) + 2 * nid) % (long)pow(2,31);
    int seq[2 * size];
    generate_c_sequence(c_init, 2 * size, seq, 0);
    for (int m = 0; m < size; m++){
        output_sequence[m] =  (float) (1 / sqrt(2)) * complex<float>(1 - 2 * seq[2 * m], 1 - 2 * seq[2 * m + 1]);
    }
}


void free5GRAN::utils::sequence_generator::generate_pdcch_dmrs_sequence(int nid, int slot_number, int symbol_number, vector<complex<float>> &output_sequence, int size){
    long c_init = (long)(pow(2, 17) * (14 * slot_number + symbol_number + 1) * (2 * nid + 1) + 2 * nid) % (long)pow(2,31);
    int seq[2 * size];
    generate_c_sequence(c_init, 2 * size, seq, 0);
    for (int m = 0; m < size; m++){
        output_sequence[m] =  (float) (1 / sqrt(2)) * complex<float>(1 - 2 * seq[2 * m], 1 - 2 * seq[2 * m + 1]);
    }
}

void free5GRAN::utils::sequence_generator::generate_pdsch_dmrs_sequence(int n_symb_slot, int slot_number, int symbol_number, int n_scid, int n_id_scid, complex<float> *output_sequence, int size){
    long c_init = (long)(pow(2, 17) * (n_symb_slot * slot_number + symbol_number + 1) * (2 * n_id_scid + 1) + 2 * n_id_scid + n_scid) % (long)pow(2,31);
    int seq[2 * size];
    generate_c_sequence(c_init, 2 * size, seq, 0);
    for (int m = 0; m < size; m++){
        output_sequence[m] =  (float) (1 / sqrt(2)) * complex<float>(1 - 2 * seq[2 * m], 1 - 2 * seq[2 * m + 1]);
    }
}