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Replaced demodulation algorithms in OFDM Decode MAC block for a more efficient version.

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[Gonzalo Arcos | Rodrigo Ferreri]
This commit is contained in:
Gonzalo Arcos
2016-04-07 17:01:59 -03:00
committed by Bastian Bloessl
parent 3703abbbf1
commit 74ae445143
1 changed files with 77 additions and 33 deletions
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lib/ofdm_decode_mac.cc
+77 -33
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@@ -40,28 +40,6 @@ ofdm_decode_mac_impl(bool log, bool debug) : block("ofdm_decode_mac",
message_port_register_out(pmt::mp("out"));
// bpsk
int bpsk_bits[] = {0, 1};
bpsk.set(cvec(BPSK_D, 2), ivec(bpsk_bits, 2));
// qpsk
int qpsk_bits[] = {0, 1, 2, 3};
qpsk.set(cvec(QPSK_D, 4), ivec(qpsk_bits, 4));
// qam16
int qam16_bits[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
qam16.set(cvec(QAM16_D, 16), ivec(qam16_bits, 16));
// qam64
int qam64_bits[] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
60, 61, 62, 63};
qam64.set(cvec(QAM64_D, 64), ivec(qam64_bits, 64));
}
int general_work (int noutput_items, gr_vector_int& ninput_items,
@@ -158,6 +136,79 @@ void decode() {
message_port_pub(pmt::mp("out"), pmt::cons(dict, blob));
}
/***** Auxiliary functions used for demodulation *****/
// BPSK
bvec demodulate_bpsk(const cvec &signal) const
{
bvec out(signal.size());
out.set_size(signal.size(), false);
for (int i = 0; i < signal.length(); i++) {
out(i) = bin(signal(i).real() > 0);
}
return out;
}
// QPSK
bvec demodulate_qpsk(const cvec &signal) const
{
int k = 2;
bvec out(k * signal.size());
out.set_size(k * signal.size(), false);
for (int i = 0; i < signal.size(); i++) {
out(k*i) = bin(signal(i).real() > 0);
out(k*i + 1) = bin(signal(i).imag() > 0);
}
return out;
}
// 16QAM
bvec demodulate_16qam(const cvec &signal) const
{
int k = 4;
bvec out(k * signal.size());
out.set_size(k * signal.size(), false);
for (int i = 0; i < signal.size(); i++) {
out(k*i) = bin(signal(i).real() > 0);
out(k*i + 1) = bin(std::abs(signal(i).real()) < 0.63245);
out(k*i + 2) = bin(signal(i).imag() > 0);
out(k*i + 3) = bin(std::abs(signal(i).imag()) < 0.63245);
}
return out;
}
// 64QAM
bvec demodulate_64qam(const cvec &signal) const
{
int k = 6;
bvec out(k * signal.size());
out.set_size(k * signal.size(), false);
for (int i = 0; i < signal.size(); i++) {
out(k*i) = bin(signal(i).real() > 0);
out(k*i + 1) = bin(std::abs(signal(i).real()) < 0.6172);
out(k*i + 2) = bin(std::abs(signal(i).real()) < 0.9258 && std::abs(signal(i).real()) > 0.3086);
out(k*i + 3) = bin(signal(i).imag() > 0);
out(k*i + 4) = bin(std::abs(signal(i).imag()) < 0.6172);
out(k*i + 5) = bin(std::abs(signal(i).imag()) < 0.9258 && std::abs(signal(i).imag()) > 0.3086);
}
return out;
}
void demodulate() {
cvec symbols;
@@ -169,23 +220,21 @@ void demodulate() {
switch(d_ofdm.encoding) {
case BPSK_1_2:
case BPSK_3_4:
bits = to_vec(bpsk.demodulate_bits(symbols));
bits = to_vec(demodulate_bpsk(symbols));
break;
case QPSK_1_2:
case QPSK_3_4:
bits = to_vec(qpsk.demodulate_bits(symbols));
bits = to_vec(demodulate_qpsk(symbols));
break;
case QAM16_1_2:
case QAM16_3_4:
bits = to_vec(qam16.demodulate_bits(symbols));
bits = to_vec(demodulate_16qam(symbols));
break;
case QAM64_2_3:
case QAM64_3_4:
bits = to_vec(qam64.demodulate_bits(symbols));
bits = to_vec(demodulate_64qam(symbols));
break;
}
@@ -318,11 +367,6 @@ private:
ofdm_param d_ofdm;
int copied;
bool d_frame_complete;
Modulator<std::complex<double> > bpsk;
Modulator<std::complex<double> > qpsk;
Modulator<std::complex<double> > qam16;
Modulator<std::complex<double> > qam64;
};
ofdm_decode_mac::sptr