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openairinterface5g/openair1/PHY/NR_TRANSPORT/nr_sss.c
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2018-10-18 23:32:51 +02:00

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3.0 KiB
C

/*
* 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
*/
#include "PHY/NR_TRANSPORT/nr_transport.h"
//#define NR_SSS_DEBUG
int nr_generate_sss( int16_t *d_sss,
int32_t **txdataF,
int16_t amp,
uint8_t ssb_start_symbol,
nfapi_nr_config_request_t* config,
NR_DL_FRAME_PARMS *frame_parms)
{
int i,k,l;
int m0, m1;
int Nid, Nid1, Nid2;
int16_t a;
int16_t x0[NR_SSS_LENGTH], x1[NR_SSS_LENGTH];
const int x0_initial[7] = { 1, 0, 0, 0, 0, 0, 0 };
const int x1_initial[7] = { 1, 0, 0, 0, 0, 0, 0 };
/// Sequence generation
Nid = config->sch_config.physical_cell_id.value;
Nid2 = Nid % 3;
Nid1 = (Nid - Nid2)/3;
for ( i=0 ; i < 7 ; i++) {
x0[i] = x0_initial[i];
x1[i] = x1_initial[i];
}
for ( i=0 ; i < NR_SSS_LENGTH - 7 ; i++) {
x0[i+7] = (x0[i + 4] + x0[i]) % 2;
x1[i+7] = (x1[i + 1] + x1[i]) % 2;
}
m0 = 15*(Nid1/112) + (5*Nid2);
m1 = Nid1 % 112;
for (i = 0; i < NR_SSS_LENGTH ; i++) {
d_sss[i] = (1 - 2*x0[(i + m0) % NR_SSS_LENGTH] ) * (1 - 2*x1[(i + m1) % NR_SSS_LENGTH] ) * 32767;
}
#ifdef NR_SSS_DEBUG
write_output("d_sss.m", "d_sss", (void*)d_sss, NR_SSS_LENGTH, 1, 1);
#endif
/// Resource mapping
a = (config->rf_config.tx_antenna_ports.value == 1) ? amp : (amp*ONE_OVER_SQRT2_Q15)>>15;
for (int aa = 0; aa < config->rf_config.tx_antenna_ports.value; aa++)
{
// SSS occupies a predefined position (subcarriers 56-182, symbol 2) within the SSB block starting from
k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + 56; //and
l = ssb_start_symbol + 2;
for (int m = 0; m < NR_SSS_LENGTH; m++) {
((int16_t*)txdataF[aa])[2*(l*frame_parms->ofdm_symbol_size + k)] = (a * d_sss[m]) >> 15;
k++;
if (k >= frame_parms->ofdm_symbol_size)
k-=frame_parms->ofdm_symbol_size;
}
}
#ifdef NR_SSS_DEBUG
// write_output("sss_0.m", "sss_0", (void*)txdataF[0][l*frame_parms->ofdm_symbol_size], frame_parms->ofdm_symbol_size, 1, 1);
#endif
return 0;
}