diff options
| author | mormj <34754695+mormj@users.noreply.github.com> | 2020-04-09 07:38:25 -0400 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-04-09 07:38:25 -0400 |
| commit | 3c1750c481a578bd831fce933502fde88444eb54 (patch) | |
| tree | b2e3baf85a1e0605fdf4b0bfcf3e4d6280dfe439 /gr-digital/include/gnuradio/digital/adaptive_algorithm.h | |
| parent | 7bc8622dda145164c97b73b1c8d4aaf3e0a8bf16 (diff) | |
digital: restructure equalizers and add dfe (#3306)
* digital: restructure equalizers and add dfe
This commit restructures the linear equalizer to have a separate
specifiable adaptive algorithm. Generally this works the same as the
previous LMS and CMA decision directed equalizers, but also adds the
ability to equalize using training sequences as well.
Also, a Decision Feedback Equalizer structure is added
* digital: more const in equalizers
* digital: equalizers - more safety based on review
* digital: dfe - use deque instead of vector for decision_history
* digital - equalizers, further cleanup
Diffstat (limited to 'gr-digital/include/gnuradio/digital/adaptive_algorithm.h')
| -rw-r--r-- | gr-digital/include/gnuradio/digital/adaptive_algorithm.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/gr-digital/include/gnuradio/digital/adaptive_algorithm.h b/gr-digital/include/gnuradio/digital/adaptive_algorithm.h new file mode 100644 index 0000000000..670bb17373 --- /dev/null +++ b/gr-digital/include/gnuradio/digital/adaptive_algorithm.h @@ -0,0 +1,90 @@ +/* -*- c++ -*- */ +/* + * Copyright 2020 Free Software Foundation, Inc. + * + * This file is part of GNU Radio + * + * SPDX-License-Identifier: GPL-3.0-or-later + * + */ + +#ifndef INCLUDED_DIGITAL_ADAPTIVE_ALGORITHM_H +#define INCLUDED_DIGITAL_ADAPTIVE_ALGORITHM_H + +#include <gnuradio/digital/api.h> +#include <gnuradio/digital/constellation.h> +#include <gnuradio/math.h> +#include <math.h> +#include <algorithm> +#include <vector> + +namespace gr { +namespace digital { +enum class adaptive_algorithm_t { LMS, NLMS, CMA }; + +class adaptive_algorithm; +typedef std::shared_ptr<adaptive_algorithm> adaptive_algorithm_sptr; + +class DIGITAL_API adaptive_algorithm + : public std::enable_shared_from_this<adaptive_algorithm> +{ +protected: + const adaptive_algorithm_t d_algorithm_type; + const constellation_sptr d_constellation; + +public: + virtual ~adaptive_algorithm() {} + + adaptive_algorithm(adaptive_algorithm_t alg_type, constellation_sptr cons) + : d_algorithm_type(alg_type), d_constellation(cons) + { + } + + adaptive_algorithm_sptr base() { return shared_from_this(); } + + virtual void initialize_taps(std::vector<gr_complex>& taps) + { + std::fill(taps.begin(), taps.end(), gr_complex(0.0, 0.0)); + taps[0] = gr_complex(1.0, 0.0); // default weights, overridden by derived classes + } + + virtual gr_complex error_dd(gr_complex& wu, gr_complex& decision) const + { + // 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_constellation->map_to_points(d_constellation->decision_maker(&wu), &decision); + return decision - wu; + } + + virtual gr_complex error_tr(const gr_complex& wu, const gr_complex& d_n) const + { + return d_n - wu; + } + + virtual gr_complex update_tap(const gr_complex tap, + const gr_complex& in, + const gr_complex error, + const gr_complex decision) = 0; + + virtual void update_taps(gr_complex* taps, + const gr_complex* in, + const gr_complex error, + const gr_complex decision, + unsigned int num_taps) + { + // default tap update until update_taps is implemented for all the alg types + // Performance can be improved in the derived algorithms by having a volk-ified + // update_taps method + for (unsigned i = 0; i < num_taps; i++) { + taps[i] = update_tap(taps[i], in[i], error, decision); + } + } +}; + +} // namespace digital +} // namespace gr +#endif
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