79 lines
2.7 KiB
C
79 lines
2.7 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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#include "PHY/NR_TRANSPORT/nr_transport_proto.h"
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//#define NR_SSS_DEBUG
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int nr_generate_sss( int32_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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int16_t x0[NR_SSS_LENGTH];
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int16_t x1[NR_SSS_LENGTH];
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const int x0_initial[7] = { 1, 0, 0, 0, 0, 0, 0 };
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const int x1_initial[7] = { 1, 0, 0, 0, 0, 0, 0 };
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/// Sequence generation
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int Nid = config->cell_config.phy_cell_id.value;
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int Nid2 = Nid % 3;
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int Nid1 = (Nid - Nid2)/3;
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for (int i=0; i < 7; i++) {
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x0[i] = x0_initial[i];
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x1[i] = x1_initial[i];
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}
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for (int i=0; i < NR_SSS_LENGTH - 7; i++) {
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x0[i+7] = (x0[i + 4] + x0[i]) % 2;
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x1[i+7] = (x1[i + 1] + x1[i]) % 2;
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}
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int m0 = 15*(Nid1/112) + (5*Nid2);
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int m1 = Nid1 % 112;
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#ifdef NR_SSS_DEBUG
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write_output("d_sss.m", "d_sss", (void*)d_sss, NR_SSS_LENGTH, 1, 1);
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#endif
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/// Resource mapping
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// SSS occupies a predefined position (subcarriers 56-182, symbol 2) within the SSB block starting from
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int k = frame_parms->first_carrier_offset + frame_parms->ssb_start_subcarrier + 56; //and
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int l = ssb_start_symbol + 2;
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for (int i = 0; i < NR_SSS_LENGTH; i++) {
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int16_t d_sss = (1 - 2*x0[(i + m0) % NR_SSS_LENGTH] ) * (1 - 2*x1[(i + m1) % NR_SSS_LENGTH] ) * 23170;
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((int16_t*)txdataF)[2*(l*frame_parms->ofdm_symbol_size + k)] = (((int16_t)amp) * d_sss) >> 15;
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k++;
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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 NR_SSS_DEBUG
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// write_output("sss_0.m", "sss_0", (void*)txdataF[0][l*frame_parms->ofdm_symbol_size], frame_parms->ofdm_symbol_size, 1, 1);
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#endif
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return 0;
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}
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