Bastian Bloessl
137 lines
3.3 KiB
C++
137 lines
3.3 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_pilot.h>
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#include "utils.h"
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#include <gnuradio/io_signature.h>
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using namespace gr::ieee802_11;
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class ofdm_pilot_impl : public ofdm_pilot {
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static const int TONES = 48;
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static const int FFT_SIZE = 64;
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public:
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ofdm_pilot_impl(bool debug) :
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sync_block ("ofdm_pilot",
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gr::io_signature::make(1, 1, TONES * sizeof(gr_complex)),
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gr::io_signature::make(1, 1, FFT_SIZE * sizeof(gr_complex))),
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d_offset(0),
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d_debug(debug) {
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}
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~ofdm_pilot_impl() {
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}
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int work (int noutput_items, 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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gr_complex *out = (gr_complex*)output_items[0];
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int i = 0;
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int count = 0;
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const uint64_t nread = nitems_read(0);
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std::vector<gr::tag_t> tags;
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while (count < noutput_items) {
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get_tags_in_range(tags, 0, nread + count, nread + count + 1, pmt::string_to_symbol("ofdm_start"));
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if(tags.size()) {
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d_offset = 0;
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dout << "OFDM PILOT: start of OFDM frame" << std::endl;
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}
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// guard band
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memset(out, 0, 6 * sizeof(gr_complex));
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// subcarriers -26 to -22
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memcpy(out + 6, in, 5 * sizeof(gr_complex));
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// pilot 1
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out[11] = POLARITY[d_offset];
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// subcarriers -20 to -8
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memcpy(out + 12, in + 5, 13 * sizeof(gr_complex));
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// pilot 2
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out[25] = POLARITY[d_offset];
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// subcarriers -6 to -1
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memcpy(out + 26, in + 18, 6 * sizeof(gr_complex));
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// DC
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out[32] = 0;
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// subcarriers 1 to 6
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memcpy(out + 33, in + 24, 6 * sizeof(gr_complex));
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// pilot 3
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out[39] = POLARITY[d_offset];
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// pubcarriers 8 to 20
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memcpy(out + 40, in + 30, 13 * sizeof(gr_complex));
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// pilot 4
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out[53] = -POLARITY[d_offset];
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// subcarriers 22 to 26
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memcpy(out + 54, in + 43, 5 * sizeof(gr_complex));
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// guard band
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memset(out + 59, 0, 5 * sizeof(gr_complex));
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count++;
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out += FFT_SIZE;
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in += TONES;
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d_offset = (d_offset + 1) % 127;
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}
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dout << "OFDM PILOT: produced items: " << noutput_items << std::endl;
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return noutput_items;
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}
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private:
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bool d_debug;
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int d_offset;
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static const gr_complex POLARITY[127];
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};
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const gr_complex ofdm_pilot_impl::POLARITY[127] = {
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1, 1, 1, 1,-1,-1,-1, 1,-1,-1,-1,-1, 1, 1,-1, 1,
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-1,-1, 1, 1,-1, 1, 1,-1, 1, 1, 1, 1, 1, 1,-1, 1,
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1, 1,-1, 1, 1,-1,-1, 1, 1, 1,-1, 1,-1,-1,-1, 1,
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-1, 1,-1,-1, 1,-1,-1, 1, 1, 1, 1, 1,-1,-1, 1, 1,
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-1,-1, 1,-1, 1,-1, 1, 1,-1,-1,-1, 1, 1,-1,-1,-1,
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-1, 1,-1,-1, 1,-1, 1, 1, 1, 1,-1, 1,-1, 1,-1, 1,
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-1,-1,-1,-1,-1, 1,-1, 1, 1,-1, 1,-1, 1, 1, 1,-1,
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-1, 1,-1,-1,-1, 1, 1, 1,-1,-1,-1,-1,-1,-1,-1 };
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ofdm_pilot::sptr
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ofdm_pilot::make(bool debug) {
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return gnuradio::get_initial_sptr(new ofdm_pilot_impl(debug));
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}
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