mirror of https://github.com/PentHertz/srsLTE.git
128 lines
3.2 KiB
C
128 lines
3.2 KiB
C
/*
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* Copyright (c) 2013, Ismael Gomez-Miguelez <gomezi@tcd.ie>.
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* This file is part of OSLD-lib (http://https://github.com/ismagom/osld-lib)
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*
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* OSLD-lib is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* OSLD-lib is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with OSLD-lib. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef PSS_
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#define PSS_
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#include <stdint.h>
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#include <stdbool.h>
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#include "utils/convolution.h"
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typedef _Complex float cf_t; /* this is only a shortcut */
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#define CONVOLUTION_FFT
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#define DEFAULT_CORRELATION_TH 10000
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#define DEFAULT_NOSYNC_TIMEOUT 5
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#define PSS_LEN_FREQ 129 // FFT-based convolution removes 1 leaving it in 128
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#define PSS_LEN 62
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#define PSS_RE 6*12
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/** The pss_synch_t object provides functions for fast computation of the crosscorrelation
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* between the PSS and received signal and CFO estimation. Also, the function pss_synch_periodic() is designed
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* to be called periodically every subframe, taking care of the correct data alignment with respect
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* to the PSS sequence.
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*/
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/* Low-level API */
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typedef struct {
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#ifdef CONVOLUTION_FFT
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conv_fft_cc_t conv_fft;
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#endif
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int frame_size;
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int N_id_2;
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float current_cfo;
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bool cfo_auto; // default true
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int nof_nosync_frames;
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int nosync_timeout_frames; // default 5
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float correlation_threshold; // default 10000
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int frame_start_idx;
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int fb_wp;
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cf_t *pss_signal_freq;
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cf_t *tmp_input;
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float *conv_abs;
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cf_t *frame_buffer;
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cf_t *conv_output;
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cf_t *tmp_nco;
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}pss_synch_t;
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/* Basic functionality */
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int pss_synch_init(pss_synch_t *q, int frame_size);
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void pss_synch_free(pss_synch_t *q);
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int pss_generate(cf_t *signal, int direction, int N_id_2);
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int pss_synch_set_N_id_2(pss_synch_t *q, int N_id_2);
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int pss_synch_find_pss(pss_synch_t *q, cf_t *input, float *corr_peak_value, float *corr_mean_value);
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float pss_synch_cfo_compute(pss_synch_t* q, cf_t *pss_recv);
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/* Automatic frame management functions (for periodic calling) */
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int pss_synch_periodic(pss_synch_t *q, cf_t *input, cf_t *output, int nsamples);
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void pss_synch_set_timeout(pss_synch_t *q, int nof_frames);
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void pss_synch_set_threshold(pss_synch_t *q, float threshold);
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void pss_synch_set_cfo_mode(pss_synch_t *q, bool cfo_auto);
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float pss_synch_get_cfo(pss_synch_t *q);
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int pss_synch_get_frame_start_idx(pss_synch_t *q);
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/* High-level API */
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typedef struct {
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pss_synch_t obj;
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struct pss_synch_init {
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int frame_size; // if 0, 2048
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int unsync_nof_pkts;
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int N_id_2;
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int do_cfo;
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} init;
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cf_t *input;
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int in_len;
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struct pss_synch_ctrl_in {
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int correlation_threshold;
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float manual_cfo;
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} ctrl_in;
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cf_t *output;
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int out_len;
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}pss_synch_hl;
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#define DEFAULT_FRAME_SIZE 2048
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int pss_synch_initialize(pss_synch_hl* h);
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int pss_synch_work(pss_synch_hl* hl);
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int pss_synch_stop(pss_synch_hl* hl);
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#endif
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