diff options
Diffstat (limited to 'gr-digital/include/digital_impl_mpsk_snr_est.h')
| -rw-r--r-- | gr-digital/include/digital_impl_mpsk_snr_est.h | 279 |
1 files changed, 0 insertions, 279 deletions
diff --git a/gr-digital/include/digital_impl_mpsk_snr_est.h b/gr-digital/include/digital_impl_mpsk_snr_est.h deleted file mode 100644 index df7dbadec1..0000000000 --- a/gr-digital/include/digital_impl_mpsk_snr_est.h +++ /dev/null @@ -1,279 +0,0 @@ -/* -*- c++ -*- */ -/* - * Copyright 2011 Free Software Foundation, Inc. - * - * This file is part of GNU Radio - * - * GNU Radio 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, or (at your option) - * any later version. - * - * GNU Radio 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 GNU Radio; see the file COPYING. If not, write to - * the Free Software Foundation, Inc., 51 Franklin Street, - * Boston, MA 02110-1301, USA. - */ -#ifndef INCLUDED_DIGITAL_IMPL_MPSK_SNR_EST_H -#define INCLUDED_DIGITAL_IMPL_MPSK_SNR_EST_H - -#include <digital_api.h> -#include <gr_sync_block.h> - -//! Enum for the type of SNR estimator to select -/*! \ingroup snr_blk - * \anchor ref_snr_est_types - * - * Below are some ROUGH estimates of what values of SNR each of these - * types of estimators is good for. In general, these offer a - * trade-off between accuracy and performance. - * - * \li SNR_EST_SIMPLE: Simple estimator (>= 7 dB) - * \li SNR_EST_SKEW: Skewness-base est (>= 5 dB) - * \li SNR_EST_M2M4: 2nd & 4th moment est (>= 1 dB) - * \li SNR_EST_SVR: SVR-based est (>= 0dB) -*/ -enum snr_est_type_t { - SNR_EST_SIMPLE = 0, // Simple estimator (>= 7 dB) - SNR_EST_SKEW, // Skewness-base est (>= 5 dB) - SNR_EST_M2M4, // 2nd & 4th moment est (>= 1 dB) - SNR_EST_SVR // SVR-based est (>= 0dB) -}; - -/*! \brief A parent class for SNR estimators, specifically for M-PSK - * signals in AWGN channels. - * \ingroup snr_blk - */ -class DIGITAL_API digital_impl_mpsk_snr_est -{ - protected: - double d_alpha, d_beta; - - public: - /*! Constructor - * - * Parameters: - * \param alpha: the update rate of internal running average - * calculations. - */ - digital_impl_mpsk_snr_est(double alpha); - virtual ~digital_impl_mpsk_snr_est(); - - //! Get the running-average coefficient - double alpha() const; - - //! Set the running-average coefficient - void set_alpha(double alpha); - - //! Update the current registers - virtual int update(int noutput_items, - const gr_complex *in); - - //! Use the register values to compute a new estimate - virtual double snr(); -}; - - -//! \brief SNR Estimator using simple mean/variance estimates. -/*! \ingroup snr_blk - * - * A very simple SNR estimator that just uses mean and variance - * estimates of an M-PSK constellation. This esimator is quick and - * cheap and accurate for high SNR (above 7 dB or so) but quickly - * starts to overestimate the SNR at low SNR. - */ -class DIGITAL_API digital_impl_mpsk_snr_est_simple : - public digital_impl_mpsk_snr_est -{ - private: - double d_y1, d_y2; - - public: - /*! Constructor - * - * Parameters: - * \param alpha: the update rate of internal running average - * calculations. - */ - digital_impl_mpsk_snr_est_simple(double alpha); - ~digital_impl_mpsk_snr_est_simple() {} - - int update(int noutput_items, - const gr_complex *in); - double snr(); -}; - - -//! \brief SNR Estimator using skewness correction. -/*! \ingroup snr_blk - * - * This is an estimator that came from a discussion between Tom - * Rondeau and fred harris with no known paper reference. The idea is - * that at low SNR, the variance estimations will be affected because - * of fold-over around the decision boundaries, which results in a - * skewness to the samples. We estimate the skewness and use this as - * a correcting term. - */ -class DIGITAL_API digital_impl_mpsk_snr_est_skew : - public digital_impl_mpsk_snr_est -{ - private: - double d_y1, d_y2, d_y3; - - public: - /*! Constructor - * - * Parameters: - * \param alpha: the update rate of internal running average - * calculations. - */ - digital_impl_mpsk_snr_est_skew(double alpha); - ~digital_impl_mpsk_snr_est_skew() {} - - int update(int noutput_items, - const gr_complex *in); - double snr(); -}; - - -//! \brief SNR Estimator using 2nd and 4th-order moments. -/*! \ingroup snr_blk - * - * An SNR estimator for M-PSK signals that uses 2nd (M2) and 4th (M4) - * order moments. This estimator uses knowledge of the kurtosis of - * the signal (k_a) and noise (k_w) to make its estimation. We use - * Beaulieu's approximations here to M-PSK signals and AWGN channels - * such that k_a=1 and k_w=2. These approximations significantly - * reduce the complexity of the calculations (and computations) - * required. - * - * Reference: - * D. R. Pauluzzi and N. C. Beaulieu, "A comparison of SNR - * estimation techniques for the AWGN channel," IEEE - * Trans. Communications, Vol. 48, No. 10, pp. 1681-1691, 2000. - */ -class DIGITAL_API digital_impl_mpsk_snr_est_m2m4 : - public digital_impl_mpsk_snr_est -{ - private: - double d_y1, d_y2; - - public: - /*! Constructor - * - * Parameters: - * \param alpha: the update rate of internal running average - * calculations. - */ - digital_impl_mpsk_snr_est_m2m4(double alpha); - ~digital_impl_mpsk_snr_est_m2m4() {} - - int update(int noutput_items, - const gr_complex *in); - double snr(); -}; - - -//! \brief SNR Estimator using 2nd and 4th-order moments. -/*! \ingroup snr_blk - * - * An SNR estimator for M-PSK signals that uses 2nd (M2) and 4th (M4) - * order moments. This estimator uses knowledge of the kurtosis of - * the signal (k_a) and noise (k_w) to make its estimation. In this - * case, you can set your own estimations for k_a and k_w, the - * kurtosis of the signal and noise, to fit this estimation better to - * your signal and channel conditions. - * - * A word of warning: this estimator has not been fully tested or - * proved with any amount of rigor. The estimation for M4 in - * particular might be ignoring effectf of when k_a and k_w are - * different. Use this estimator with caution and a copy of the - * reference on hand. - * - * The digital_mpsk_snr_est_m2m4 assumes k_a and k_w to simplify the - * computations for M-PSK and AWGN channels. Use that estimator - * unless you have a way to guess or estimate these values here. - * - * Original paper: - * R. Matzner, "An SNR estimation algorithm for complex baseband - * signal using higher order statistics," Facta Universitatis - * (Nis), no. 6, pp. 41-52, 1993. - * - * Reference used in derivation: - * D. R. Pauluzzi and N. C. Beaulieu, "A comparison of SNR - * estimation techniques for the AWGN channel," IEEE - * Trans. Communications, Vol. 48, No. 10, pp. 1681-1691, 2000. - */ -class DIGITAL_API digital_impl_snr_est_m2m4 : - public digital_impl_mpsk_snr_est -{ - private: - double d_y1, d_y2; - double d_ka, d_kw; - - public: - /*! Constructor - * - * Parameters: - * \param alpha: the update rate of internal running average - * calculations. - * \param ka: estimate of the signal kurtosis (1 for PSK) - * \param kw: estimate of the channel noise kurtosis (2 for AWGN) - */ - digital_impl_snr_est_m2m4(double alpha, double ka, double kw); - ~digital_impl_snr_est_m2m4() {} - - int update(int noutput_items, - const gr_complex *in); - double snr(); -}; - - -//! \brief Signal-to-Variation Ratio SNR Estimator. -/*! \ingroup snr_blk - * - * This estimator actually comes from an SNR estimator for M-PSK - * signals in fading channels, but this implementation is - * specifically for AWGN channels. The math was simplified to assume - * a signal and noise kurtosis (k_a and k_w) for M-PSK signals in - * AWGN. These approximations significantly reduce the complexity of - * the calculations (and computations) required. - * - * Original paper: - * A. L. Brandao, L. B. Lopes, and D. C. McLernon, "In-service - * monitoring of multipath delay and cochannel interference for - * indoor mobile communication systems," Proc. IEEE - * Int. Conf. Communications, vol. 3, pp. 1458-1462, May 1994. - * - * Reference: - * D. R. Pauluzzi and N. C. Beaulieu, "A comparison of SNR - * estimation techniques for the AWGN channel," IEEE - * Trans. Communications, Vol. 48, No. 10, pp. 1681-1691, 2000. - */ -class DIGITAL_API digital_impl_mpsk_snr_est_svr : - public digital_impl_mpsk_snr_est -{ - private: - double d_y1, d_y2; - - public: - /*! Constructor - * - * Parameters: - * \param alpha: the update rate of internal running average - * calculations. - */ - digital_impl_mpsk_snr_est_svr(double alpha); - ~digital_impl_mpsk_snr_est_svr() {} - - int update(int noutput_items, - const gr_complex *in); - double snr(); -}; - -#endif /* INCLUDED_DIGITAL_IMPL_MPSK_SNR_EST_H */ |