Sakthivel Velumani
043da0c440
Till this commit, the UE gets the position of SSB in frequency from command line and does the syncronization by locating the SSB in time. It does this by generating a PSS time signal during initialization with the SSB offset given via command line. Then PSS detection is done by correlation. In this commit, the UE computes a list of GSCN in the current NR band that falls within the current bandwidth for the set center frequency. For each GSCN in the list, the UE starts a thread and performs the following: 1. Generate PSS time signal with SSB offset for current GSCN. 2. Detect PSS, SSS and decode PBCH (this step remains the same). After all threads finishes, the results are collected. For now, only the first detected PBCH is used to proceed further. So this PBCH is indicated to MAC and UE exits initial sync. Future work: The cell search can be standalone feature where the UE could scan for SSB in the entire NR band. This would require changing radio's frequency on the fly as the UE's bandwidth would not cover an entire NR band. The cell detection can futher be imporved by looking for SIB1 for each decoded PBCH.
110 lines
3.7 KiB
C
110 lines
3.7 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 1.0 (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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/***********************************************************************
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*
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* FILENAME : sss_nr.h
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*
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* MODULE : Secondary synchronisation signal
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*
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* DESCRIPTION : variables related to sss
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*
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************************************************************************/
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#ifndef SSS_NR_H
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#define SSS_NR_H
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#include "limits.h"
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#include "PHY/defs_nr_UE.h"
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#include "PHY/types.h"
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#include "pss_nr.h"
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/************** DEFINE ********************************************/
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#define SAMPLES_IQ (sizeof(int16_t)*2)
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#define NUMBER_SSS_SEQUENCE (336)
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#define INVALID_SSS_SEQUENCE (NUMBER_SSS_SEQUENCE)
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#define LENGTH_SSS_NR (127)
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#define SCALING_METRIC_SSS_NR (15)//(19)
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#define N_ID_2_NUMBER (NUMBER_PSS_SEQUENCE)
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#define N_ID_2_NUMBER_SL (NUMBER_PSS_SEQUENCE_SL)
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#define N_ID_1_NUMBER (NUMBER_SSS_SEQUENCE)
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#define GET_NID2(Nid_cell) (Nid_cell%3)
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#define GET_NID1(Nid_cell) (Nid_cell/3)
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#define GET_NID2_SL(Nid_SL) (Nid_SL/NUMBER_SSS_SEQUENCE)
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#define GET_NID1_SL(Nid_SL) (Nid_SL%NUMBER_SSS_SEQUENCE)
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#define PSS_SC_START_NR (52) /* see from TS 38.211 table 7.4.3.1-1: Resources within an SS/PBCH block for PSS... */
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#define SSS_START_IDX (3) /* [0:PSBCH 1:PSS0 2:PSS1 3:SSS0 4:SSS1] */
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#define NUM_SSS_SYMBOLS (2)
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#define SSS_METRIC_FLOOR_NR (30000)
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/************** VARIABLES *****************************************/
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#define PHASE_HYPOTHESIS_NUMBER (16)
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#define INDEX_NO_PHASE_DIFFERENCE (3) /* this is for no phase shift case */
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/************** FUNCTION ******************************************/
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static const c16_t phase_nr[PHASE_HYPOTHESIS_NUMBER] = {
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// {pi/3 ---- pi/3, -pi/3 ---- pi/3}
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{16384, -28377},
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{20173, -25821},
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{23571, -22762},
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{26509, -19260},
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{28932, -15383},
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{30791, -11207},
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{32051, -6813},
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{32687, -2286},
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{32687, 2286},
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{32051, 6813},
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{30791, 11207},
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{28932, 15383},
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{26509, 19260},
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{23571, 22762},
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{20173, 25821},
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{16384, 28377}};
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void init_context_sss_nr(int amp);
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void free_context_sss_nr(void);
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void insert_sss_nr(int16_t *sss_time,
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NR_DL_FRAME_PARMS *frame_parms);
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bool rx_sss_nr(const NR_DL_FRAME_PARMS *frame_parms,
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int nid2,
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int target_Nid_cell,
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int freq_offset_pss,
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int ssb_start_subcarrier,
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int *Nid_cell,
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int32_t *tot_metric,
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uint8_t *phase_max,
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int *freq_offset_sss,
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c16_t rxdataF[][frame_parms->samples_per_slot_wCP]);
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#endif /* SSS_NR_H */
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