Bastian Bloessl
85 lines
2.7 KiB
C++
85 lines
2.7 KiB
C++
/*
|
|
* Copyright (C) 2015 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 "comb.h"
|
|
|
|
using namespace gr::ieee802_11::equalizer;
|
|
|
|
void comb::equalize(gr_complex* in,
|
|
int n,
|
|
gr_complex* symbols,
|
|
uint8_t* bits,
|
|
boost::shared_ptr<gr::digital::constellation> mod)
|
|
{
|
|
|
|
gr_complex pilot[4];
|
|
|
|
if (n < 2) {
|
|
pilot[0] = in[11];
|
|
pilot[1] = -in[25];
|
|
pilot[2] = in[39];
|
|
pilot[3] = in[53];
|
|
} else {
|
|
gr_complex p = POLARITY[(n - 2) % 127];
|
|
pilot[0] = in[11] * p;
|
|
pilot[1] = in[25] * p;
|
|
pilot[2] = in[39] * p;
|
|
pilot[3] = in[53] * -p;
|
|
}
|
|
|
|
gr_complex avg = (pilot[0] + pilot[1] + pilot[2] + pilot[3]) / gr_complex(4, 0);
|
|
|
|
for (int i = 0; i < 64; i++) {
|
|
gr_complex H;
|
|
if (i <= 11) {
|
|
H = gr_complex((11 - i) / 11.0, 0) * avg + gr_complex(i / 11.0, 0) * pilot[0];
|
|
} else if (i <= 25) {
|
|
H = gr_complex((25 - i) / 14.0, 0) * pilot[0] +
|
|
gr_complex((i - 11) / 14.0, 0) * pilot[1];
|
|
} else if (i <= 39) {
|
|
H = gr_complex((39 - i) / 14.0, 0) * pilot[1] +
|
|
gr_complex((i - 25) / 14.0, 0) * pilot[2];
|
|
} else if (i <= 53) {
|
|
H = gr_complex((53 - i) / 14.0, 0) * pilot[2] +
|
|
gr_complex((i - 39) / 14.0, 0) * pilot[3];
|
|
} else {
|
|
H = gr_complex((64 - i) / 11.0, 0) * pilot[3] +
|
|
gr_complex((i - 53) / 11.0, 0) * avg;
|
|
}
|
|
|
|
if (n == 0) {
|
|
d_H[i] = H;
|
|
} else {
|
|
d_H[i] = gr_complex(1 - alpha, 0) * d_H[i] + gr_complex(alpha, 0) * H;
|
|
}
|
|
}
|
|
|
|
int c = 0;
|
|
for (int i = 0; i < 64; i++) {
|
|
if ((i == 11) || (i == 25) || (i == 32) || (i == 39) || (i == 53) || (i < 6) ||
|
|
(i > 58)) {
|
|
continue;
|
|
} else {
|
|
symbols[c] = in[i] / d_H[i];
|
|
bits[c] = mod->decision_maker(&symbols[c]);
|
|
c++;
|
|
}
|
|
}
|
|
}
|
|
|
|
double comb::get_snr() { return 42; }
|