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gr-ieee802-11/lib/utils.cc
T
Bastian Bloessl 760fc86101 rename
2016-04-20 07:45:49 +02:00

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9.7 KiB
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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 "utils.h"
#include <cassert>
#include <cstring>
#include <math.h>
// constellations for different modulations (normalized to avg power 1)
const std::complex<double> BPSK_D[2] = {
std::complex<double>(-1.0, 0.0), std::complex<double>(1.0, 0.0)};
const std::complex<double> QPSK_D[4] = {
std::complex<double>(-0.7071, -0.7071), std::complex<double>(-0.7071, 0.7071),
std::complex<double>(+0.7071, -0.7071), std::complex<double>(+0.7071, 0.7071)};
const std::complex<double> QAM16_D[16] = {
std::complex<double>(-0.9487, -0.9487), std::complex<double>(-0.9487, -0.3162),
std::complex<double>(-0.9487, 0.9487), std::complex<double>(-0.9487, 0.3162),
std::complex<double>(-0.3162, -0.9487), std::complex<double>(-0.3162, -0.3162),
std::complex<double>(-0.3162, 0.9487), std::complex<double>(-0.3162, 0.3162),
std::complex<double>(0.9487, -0.9487), std::complex<double>(0.9487, -0.3162),
std::complex<double>(0.9487, 0.9487), std::complex<double>(0.9487, 0.3162),
std::complex<double>(0.3162, -0.9487), std::complex<double>(0.3162, -0.3162),
std::complex<double>(0.3162, 0.9487), std::complex<double>(0.3162, 0.3162)};
const std::complex<double> QAM64_D[64] = {
std::complex<double>(-1.0801, -1.0801), std::complex<double>(-1.0801, -0.7715),
std::complex<double>(-1.0801, -0.1543), std::complex<double>(-1.0801, -0.4629),
std::complex<double>(-1.0801, 1.0801), std::complex<double>(-1.0801, 0.7715),
std::complex<double>(-1.0801, 0.1543), std::complex<double>(-1.0801, 0.4629),
std::complex<double>(-0.7715, -1.0801), std::complex<double>(-0.7715, -0.7715),
std::complex<double>(-0.7715, -0.1543), std::complex<double>(-0.7715, -0.4629),
std::complex<double>(-0.7715, 1.0801), std::complex<double>(-0.7715, 0.7715),
std::complex<double>(-0.7715, 0.1543), std::complex<double>(-0.7715, 0.4629),
std::complex<double>(-0.1543, -1.0801), std::complex<double>(-0.1543, -0.7715),
std::complex<double>(-0.1543, -0.1543), std::complex<double>(-0.1543, -0.4629),
std::complex<double>(-0.1543, 1.0801), std::complex<double>(-0.1543, 0.7715),
std::complex<double>(-0.1543, 0.1543), std::complex<double>(-0.1543, 0.4629),
std::complex<double>(-0.4629, -1.0801), std::complex<double>(-0.4629, -0.7715),
std::complex<double>(-0.4629, -0.1543), std::complex<double>(-0.4629, -0.4629),
std::complex<double>(-0.4629, 1.0801), std::complex<double>(-0.4629, 0.7715),
std::complex<double>(-0.4629, 0.1543), std::complex<double>(-0.4629, 0.4629),
std::complex<double>(1.0801, -1.0801), std::complex<double>(1.0801, -0.7715),
std::complex<double>(1.0801, -0.1543), std::complex<double>(1.0801, -0.4629),
std::complex<double>(1.0801, 1.0801), std::complex<double>(1.0801, 0.7715),
std::complex<double>(1.0801, 0.1543), std::complex<double>(1.0801, 0.4629),
std::complex<double>(0.7715, -1.0801), std::complex<double>(0.7715, -0.7715),
std::complex<double>(0.7715, -0.1543), std::complex<double>(0.7715, -0.4629),
std::complex<double>(0.7715, 1.0801), std::complex<double>(0.7715, 0.7715),
std::complex<double>(0.7715, 0.1543), std::complex<double>(0.7715, 0.4629),
std::complex<double>(0.1543, -1.0801), std::complex<double>(0.1543, -0.7715),
std::complex<double>(0.1543, -0.1543), std::complex<double>(0.1543, -0.4629),
std::complex<double>(0.1543, 1.0801), std::complex<double>(0.1543, 0.7715),
std::complex<double>(0.1543, 0.1543), std::complex<double>(0.1543, 0.4629),
std::complex<double>(0.4629, -1.0801), std::complex<double>(0.4629, -0.7715),
std::complex<double>(0.4629, -0.1543), std::complex<double>(0.4629, -0.4629),
std::complex<double>(0.4629, 1.0801), std::complex<double>(0.4629, 0.7715),
std::complex<double>(0.4629, 0.1543), std::complex<double>(0.4629, 0.4629)};
ofdm_param::ofdm_param(Encoding e) {
encoding = e;
switch(e) {
case BPSK_1_2:
n_bpsc = 1;
n_cbps = 48;
n_dbps = 24;
rate_field = 0x0D; // 0b00001101
break;
case BPSK_3_4:
n_bpsc = 1;
n_cbps = 48;
n_dbps = 36;
rate_field = 0x0F; // 0b00001111
break;
case QPSK_1_2:
n_bpsc = 2;
n_cbps = 96;
n_dbps = 48;
rate_field = 0x05; // 0b00000101
break;
case QPSK_3_4:
n_bpsc = 2;
n_cbps = 96;
n_dbps = 72;
rate_field = 0x07; // 0b00000111
break;
case QAM16_1_2:
n_bpsc = 4;
n_cbps = 192;
n_dbps = 96;
rate_field = 0x09; // 0b00001001
break;
case QAM16_3_4:
n_bpsc = 4;
n_cbps = 192;
n_dbps = 144;
rate_field = 0x0B; // 0b00001011
break;
case QAM64_2_3:
n_bpsc = 6;
n_cbps = 288;
n_dbps = 192;
rate_field = 0x01; // 0b00000001
break;
case QAM64_3_4:
n_bpsc = 6;
n_cbps = 288;
n_dbps = 216;
rate_field = 0x03; // 0b00000011
break;
defaut:
assert(false);
break;
}
}
void
ofdm_param::print() {
std::cout << "OFDM Parameters:" << std::endl;
std::cout << "endcoding :" << encoding << std::endl;
std::cout << "rate_field :" << (int)rate_field << std::endl;
std::cout << "n_bpsc :" << n_bpsc << std::endl;
std::cout << "n_cbps :" << n_cbps << std::endl;
std::cout << "n_dbps :" << n_dbps << std::endl;
}
frame_param::frame_param(ofdm_param &ofdm, int psdu_length) {
psdu_size = psdu_length;
// number of symbols (17-11)
n_sym = (int) ceil((16 + 8 * psdu_size + 6) / (double) ofdm.n_dbps);
// number of bits of the data field (17-12)
n_data = n_sym * ofdm.n_dbps;
// number of padding bits (17-13)
n_pad = n_data - (16 + 8 * psdu_size + 6);
n_encoded_bits = n_sym * ofdm.n_cbps;
}
void
frame_param::print() {
std::cout << "FRAME Parameters:" << std::endl;
std::cout << "psdu_size: " << psdu_size << std::endl;
std::cout << "n_sym: " << n_sym << std::endl;
std::cout << "n_data: " << n_data << std::endl;
std::cout << "n_pad: " << n_pad << std::endl;
}
void scramble(const char *in, char *out, frame_param &frame, char initial_state) {
int state = initial_state;
int feedback;
for (int i = 0; i < frame.n_data; i++) {
feedback = (!!(state & 64)) ^ (!!(state & 8));
out[i] = feedback ^ in[i];
state = ((state << 1) & 0x7e) | feedback;
}
}
void reset_tail_bits(char *scrambled_data, frame_param &frame) {
memset(scrambled_data + frame.n_data - frame.n_pad - 6, 0, 6 * sizeof(char));
}
int ones(int n) {
int sum = 0;
for(int i = 0; i < 8; i++) {
if(n & (1 << i)) {
sum++;
}
}
return sum;
}
void convolutional_encoding(const char *in, char *out, frame_param &frame) {
int state = 0;
for(int i = 0; i < frame.n_data; i++) {
assert(in[i] == 0 || in[i] == 1);
state = ((state << 1) & 0x7e) | in[i];
out[i * 2] = ones(state & 0155) % 2;
out[i * 2 + 1] = ones(state & 0117) % 2;
}
}
void puncturing(const char *in, char *out, frame_param &frame, ofdm_param &ofdm) {
int mod;
for (int i = 0; i < frame.n_data * 2; i++) {
switch(ofdm.encoding) {
case BPSK_1_2:
case QPSK_1_2:
case QAM16_1_2:
*out = in[i];
out++;
break;
case QAM64_2_3:
if (i % 4 != 3) {
*out = in[i];
out++;
}
break;
case BPSK_3_4:
case QPSK_3_4:
case QAM16_3_4:
case QAM64_3_4:
mod = i % 6;
if (!(mod == 3 || mod == 4)) {
*out = in[i];
out++;
}
break;
defaut:
assert(false);
break;
}
}
}
void interleave(const char *in, char *out, frame_param &frame, ofdm_param &ofdm, bool reverse) {
int n_cbps = ofdm.n_cbps;
int first[n_cbps];
int second[n_cbps];
int s = std::max(ofdm.n_bpsc / 2, 1);
for(int j = 0; j < n_cbps; j++) {
first[j] = s * (j / s) + ((j + int(floor(16.0 * j / n_cbps))) % s);
}
for(int i = 0; i < n_cbps; i++) {
second[i] = 16 * i - (n_cbps - 1) * int(floor(16.0 * i / n_cbps));
}
for(int i = 0; i < frame.n_sym; i++) {
for(int k = 0; k < n_cbps; k++) {
if(reverse) {
out[i * n_cbps + second[first[k]]] = in[i * n_cbps + k];
} else {
out[i * n_cbps + k] = in[i * n_cbps + second[first[k]]];
}
}
}
}
void interleave(const double *in, double *out, frame_param &frame, ofdm_param &ofdm, bool reverse) {
int n_cbps = ofdm.n_cbps;
int first[n_cbps];
int second[n_cbps];
int s = std::max(ofdm.n_bpsc / 2, 1);
for(int j = 0; j < n_cbps; j++) {
first[j] = s * (j / s) + ((j + int(floor(16.0 * j / n_cbps))) % s);
}
for(int i = 0; i < n_cbps; i++) {
second[i] = 16 * i - (n_cbps - 1) * int(floor(16.0 * i / n_cbps));
}
for(int i = 0; i < frame.n_sym; i++) {
for(int k = 0; k < n_cbps; k++) {
if(reverse) {
out[i * n_cbps + second[first[k]]] = in[i * n_cbps + k];
} else {
out[i * n_cbps + k] = in[i * n_cbps + second[first[k]]];
}
}
}
}
void split_symbols(const char *in, char *out, frame_param &frame, ofdm_param &ofdm) {
int symbols = frame.n_sym * 48;
for (int i = 0; i < symbols; i++) {
out[i] = 0;
for(int k = 0; k < ofdm.n_bpsc; k++) {
assert(*in == 1 || *in == 0);
out[i] |= (*in << (ofdm.n_bpsc - k - 1));
in++;
}
}
}
void generate_bits(const char *psdu, char *data_bits, frame_param &frame) {
// first 16 bits are zero (SERVICE/DATA field)
memset(data_bits, 0, 16);
data_bits += 16;
for(int i = 0; i < frame.psdu_size; i++) {
for(int b = 0; b < 8; b++) {
data_bits[i * 8 + b] = !!(psdu[i] & (1 << b));
}
}
}
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