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/* -*- c++ -*- */
/*
* Copyright 2011,2012 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "lms_dd_equalizer_cc_impl.h"
#include <gnuradio/io_signature.h>
#include <gnuradio/misc.h>
#include <volk/volk.h>
namespace gr {
namespace digital {
using namespace filter::kernel;
lms_dd_equalizer_cc::sptr
lms_dd_equalizer_cc::make(int num_taps, float mu, int sps, constellation_sptr cnst)
{
return gnuradio::get_initial_sptr(
new lms_dd_equalizer_cc_impl(num_taps, mu, sps, cnst));
}
lms_dd_equalizer_cc_impl::lms_dd_equalizer_cc_impl(int num_taps,
float mu,
int sps,
constellation_sptr cnst)
: sync_decimator("lms_dd_equalizer_cc",
io_signature::make(1, 1, sizeof(gr_complex)),
io_signature::make(1, 1, sizeof(gr_complex)),
sps),
fir_filter_ccc(sps, std::vector<gr_complex>(num_taps, gr_complex(0, 0))),
d_new_taps(num_taps, gr_complex(0, 0)),
d_updated(false),
d_cnst(cnst)
{
set_gain(mu);
if (num_taps > 0)
d_new_taps[0] = 1.0;
fir_filter_ccc::set_taps(d_new_taps);
const int alignment_multiple = volk_get_alignment() / sizeof(gr_complex);
set_alignment(std::max(1, alignment_multiple));
set_history(num_taps);
}
lms_dd_equalizer_cc_impl::~lms_dd_equalizer_cc_impl() {}
void lms_dd_equalizer_cc_impl::set_taps(const std::vector<gr_complex>& taps)
{
d_new_taps = taps;
d_updated = true;
}
std::vector<gr_complex> lms_dd_equalizer_cc_impl::taps() const { return d_taps; }
gr_complex lms_dd_equalizer_cc_impl::error(const gr_complex& out)
{
gr_complex decision, error;
// The `map_to_points` function will treat `decision` as an array pointer.
// This call is "safe" because `map_to_points` is limited by the
// dimensionality of the constellation. This class calls the
// `constellation` class default constructor, which initializes the
// dimensionality value to `1`. Thus, Only the single `gr_complex` value
// will be dereferenced.
d_cnst->map_to_points(d_cnst->decision_maker(&out), &decision);
error = decision - out;
return error;
}
void lms_dd_equalizer_cc_impl::update_tap(gr_complex& tap, const gr_complex& in)
{
tap += d_mu * conj(in) * d_error;
}
int lms_dd_equalizer_cc_impl::work(int noutput_items,
gr_vector_const_void_star& input_items,
gr_vector_void_star& output_items)
{
const gr_complex* in = (const gr_complex*)input_items[0];
gr_complex* out = (gr_complex*)output_items[0];
if (d_updated) {
d_taps = d_new_taps;
set_history(d_taps.size());
d_updated = false;
return 0; // history requirements may have changed.
}
int j = 0;
size_t k, l = d_taps.size();
for (int i = 0; i < noutput_items; i++) {
out[i] = filter(&in[j]);
// Adjust taps
d_error = error(out[i]);
for (k = 0; k < l; k++) {
// Update tap locally from error.
update_tap(d_taps[k], in[j + k]);
// Update aligned taps in filter object.
fir_filter_ccc::update_tap(d_taps[k], k);
}
j += decimation();
}
return noutput_items;
}
} /* namespace digital */
} /* namespace gr */
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