Bastian Bloessl
157 lines
3.8 KiB
C++
157 lines
3.8 KiB
C++
/*
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* Copyright (C) 2013 Bastian Bloessl <bloessl@ccs-labs.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU 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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* This program 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 General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <ieee802-11/ofdm_sync_short.h>
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#include <gnuradio/io_signature.h>
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#include "utils.h"
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#include <iostream>
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using namespace gr::ieee802_11;
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static const int MIN_GAP = 480;
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class ofdm_sync_short_impl : public ofdm_sync_short {
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public:
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ofdm_sync_short_impl(double threshold, unsigned int max_samples,
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unsigned int min_plateau, bool log, bool debug) : block("ofdm_sync_short",
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gr::io_signature::make2(2, 2, sizeof(gr_complex), sizeof(float)),
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gr::io_signature::make(1, 1, sizeof(gr_complex))),
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d_log(log),
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d_debug(debug),
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d_state(SEARCH),
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d_plateau(0),
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MAX_SAMPLES(max_samples),
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MIN_PLATEAU(min_plateau),
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d_threshold(threshold) {
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set_tag_propagation_policy(block::TPP_DONT);
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}
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~ofdm_sync_short_impl(){
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}
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int general_work (int noutput_items, gr_vector_int& ninput_items,
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gr_vector_const_void_star& input_items,
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gr_vector_void_star& output_items) {
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const gr_complex *in = (const gr_complex*)input_items[0];
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const float *in2 = (const float*)input_items[1];
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gr_complex *out = (gr_complex*)output_items[0];
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int noutput = noutput_items;
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int ninput = std::min(ninput_items[0], ninput_items[1]);
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// dout << "SHORT noutput : " << noutput << " ninput: " << ninput_items[0] << std::endl;
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switch(d_state) {
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case SEARCH: {
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int i;
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for(i = 0; i < ninput; i++) {
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if(in2[i] > d_threshold) {
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if(d_plateau < MIN_PLATEAU) {
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d_plateau++;
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} else {
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d_state = COPY;
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d_copy_left = MAX_SAMPLES;
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d_plateau = 0;
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insert_tag(nitems_written(0));
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dout << "SHORT Frame!" << std::endl;
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break;
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}
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} else {
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d_plateau = 0;
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}
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}
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consume(0, i);
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consume(1, i);
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return 0;
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}
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case COPY: {
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int o = 0;
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while( (o < ninput) && (o < noutput) && d_copy_left) {
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if(in2[o] > d_threshold) {
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if(d_plateau < MIN_PLATEAU) {
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d_plateau++;
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// there's another frame
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} else if((MAX_SAMPLES - d_copy_left) > MIN_GAP) {
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d_copy_left = MAX_SAMPLES;
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d_plateau = 0;
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insert_tag(nitems_written(0) + o);
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dout << "SHORT Frame!" << std::endl;
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break;
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}
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} else {
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d_plateau = 0;
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}
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out[o] = in[o];
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o++;
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d_copy_left--;
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}
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if(!d_copy_left) {
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d_state = SEARCH;
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}
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dout << "SHORT copied " << o << std::endl;
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consume(0, o);
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consume(1, o);
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return o;
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}
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}
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throw std::runtime_error("sync short: unknown state");
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return 0;
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}
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void insert_tag(uint64_t item) {
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mylog(boost::format("frame start at %1%") % item);
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const pmt::pmt_t key = pmt::string_to_symbol("ofdm_start");
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const pmt::pmt_t value = pmt::PMT_T;
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const pmt::pmt_t srcid = pmt::string_to_symbol(name());
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add_item_tag(0, item, key, value, srcid);
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}
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private:
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enum {SEARCH, COPY} d_state;
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int d_copy_left;
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int d_plateau;
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const double d_threshold;
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const bool d_log;
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const bool d_debug;
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const unsigned int MAX_SAMPLES;
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const unsigned int MIN_PLATEAU;
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};
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ofdm_sync_short::sptr
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ofdm_sync_short::make(double threshold, unsigned int max_samples,
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unsigned int min_plateau, bool log, bool debug) {
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return gnuradio::get_initial_sptr(new ofdm_sync_short_impl(threshold,
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max_samples, min_plateau, log, debug));
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}
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