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add wifi signal header

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This commit is contained in:
Bastian Bloessl
2013-12-31 12:52:02 +01:00
parent dab44836f5
commit c64d175178
3 changed files with 230 additions and 0 deletions
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include/ieee802-11/wifi_signal_field.h
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/*
* Copyright (C) 2013 Bastian Bloessl <bloessl@ccs-labs.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_IEEE802_11_WIFI_SIGNAL_FIELD_H
#define INCLUDED_IEEE802_11_WIFI_SIGNAL_FIELD_H
#include <ieee802-11/api.h>
#include <gnuradio/digital/packet_header_default.h>
namespace gr {
namespace ieee802_11 {
class IEEE802_11_API wifi_signal_field : virtual public digital::packet_header_default
{
public:
typedef boost::shared_ptr<wifi_signal_field> sptr;
static sptr make();
protected:
wifi_signal_field();
};
} // namespace ieee802_11
} // namespace gr
#endif /* INCLUDED_IEEE802_11_WIFI_SIGNAL_FIELD_H */
lib/wifi_signal_field_impl.cc
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/*
* Copyright (C) 2013 Bastian Bloessl <bloessl@ccs-labs.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "wifi_signal_field_impl.h"
#include "utils.h"
#include <gnuradio/digital/lfsr.h>
using namespace gr::ieee802_11;
wifi_signal_field::sptr
wifi_signal_field::make() {
return wifi_signal_field::sptr(new wifi_signal_field_impl());
}
wifi_signal_field::wifi_signal_field() : packet_header_default(48, "packet_len") {};
wifi_signal_field_impl::wifi_signal_field_impl() : packet_header_default(48, "packet_len") {}
wifi_signal_field_impl::~wifi_signal_field_impl() {}
int wifi_signal_field_impl::get_bit(int b, int i) {
return (b & (1 << i) ? 1 : 0);
}
void wifi_signal_field_impl::generate_signal_field(char *out, tx_param &tx, ofdm_param &ofdm) {
//data bits of the signal header
char *signal_header = (char *) malloc(sizeof(char) * 24);
//signal header after...
//convolutional encoding
char *encoded_signal_header = (char *) malloc(sizeof(char) * 48);
//interleaving
char *interleaved_signal_header = (char *) malloc(sizeof(char) * 48);
int length = tx.psdu_size;
// first 4 bits represent the modulation and coding scheme
signal_header[ 0] = get_bit(ofdm.rate_field, 3);
signal_header[ 1] = get_bit(ofdm.rate_field, 2);
signal_header[ 2] = get_bit(ofdm.rate_field, 1);
signal_header[ 3] = get_bit(ofdm.rate_field, 0);
// 5th bit is reserved and must be set to 0
signal_header[ 4] = 0;
// then 12 bits represent the length
signal_header[ 5] = get_bit(length, 0);
signal_header[ 6] = get_bit(length, 1);
signal_header[ 7] = get_bit(length, 2);
signal_header[ 8] = get_bit(length, 3);
signal_header[ 9] = get_bit(length, 4);
signal_header[10] = get_bit(length, 5);
signal_header[11] = get_bit(length, 6);
signal_header[12] = get_bit(length, 7);
signal_header[13] = get_bit(length, 8);
signal_header[14] = get_bit(length, 9);
signal_header[15] = get_bit(length, 10);
signal_header[16] = get_bit(length, 11);
//18-th bit is the parity bit for the first 17 bits
int sum = 0;
for(int i = 0; i < 17; i++) {
if(signal_header[i]) {
sum++;
}
}
signal_header[17] = sum % 2;
// last 6 bits must be set to 0
for (int i = 0; i < 6; i++) {
signal_header[18 + i] = 0;
}
ofdm_param signal_ofdm(BPSK_1_2);
tx_param signal_tx(signal_ofdm, 3);
signal_tx.n_data = 24;
signal_tx.n_sym = 1;
// convolutional encoding (scrambling is not needed)
convolutional_encoding(signal_header, encoded_signal_header, signal_tx);
// interleaving
//interleave(encoded_signal_header, interleaved_signal_header, signal_tx, signal_ofdm);
interleave(encoded_signal_header, out, signal_tx, signal_ofdm);
free(signal_header);
free(encoded_signal_header);
free(interleaved_signal_header);
}
bool wifi_signal_field_impl::header_formatter(long packet_len, unsigned char *out, const std::vector<tag_t> &tags)
{
bool encoding_found = false;
bool len_found = false;
int encoding = 0;
int len = 0;
// read tags
for(int i = 0; i < tags.size(); i++) {
if(pmt::eq(tags[i].key, pmt::mp("encoding"))) {
encoding_found = true;
encoding = pmt::to_long(tags[i].value);
} else if(pmt::eq(tags[i].key, pmt::mp("psdu_len"))) {
len_found = true;
len = pmt::to_long(tags[i].value);
}
}
// check if all tags are present
if( (!encoding_found) || (!len_found)) {
return false;
}
ofdm_param ofdm((Encoding)encoding);
tx_param tx(ofdm, len);
generate_signal_field((char*)out, tx, ofdm);
return true;
}
bool wifi_signal_field_impl::header_parser(
const unsigned char *in, std::vector<tag_t> &tags) {
throw std::runtime_error("not implemented yet");
return false;
}
lib/wifi_signal_field_impl.h
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/*
* Copyright (C) 2013 Bastian Bloessl <bloessl@ccs-labs.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef INCLUDED_IEEE802_11_WIFI_SIGNAL_FIELD_IMPL_H
#define INCLUDED_IEEE802_11_WIFI_SIGNAL_FIELD_IMPL_H
#include <ieee802-11/wifi_signal_field.h>
#include "utils.h"
namespace gr {
namespace ieee802_11 {
class wifi_signal_field_impl : public wifi_signal_field
{
public:
wifi_signal_field_impl();
~wifi_signal_field_impl();
bool header_formatter(long packet_len, unsigned char *out,
const std::vector<tag_t> &tags);
bool header_parser(const unsigned char *header,
std::vector<tag_t> &tags);
private:
int get_bit(int b, int i);
void generate_signal_field(char *out, tx_param &tx, ofdm_param &ofdm);
};
} // namespace ieee802_11
} // namespace gr
#endif /* INCLUDED_IEEE802_11_WIFI_SIGNAL_FIELD_IMPL_H */