summaryrefslogtreecommitdiff
path: root/gr-digital/include
diff options
context:
space:
mode:
Diffstat (limited to 'gr-digital/include')
-rw-r--r--gr-digital/include/CMakeLists.txt3
-rw-r--r--gr-digital/include/Makefile.am3
-rw-r--r--gr-digital/include/digital_impl_mpsk_snr_est.h279
-rw-r--r--gr-digital/include/digital_mpsk_snr_est_cc.h115
-rw-r--r--gr-digital/include/digital_probe_mpsk_snr_est_c.h113
5 files changed, 513 insertions, 0 deletions
diff --git a/gr-digital/include/CMakeLists.txt b/gr-digital/include/CMakeLists.txt
index cf20bd1e7..81ed8d368 100644
--- a/gr-digital/include/CMakeLists.txt
+++ b/gr-digital/include/CMakeLists.txt
@@ -22,6 +22,7 @@
########################################################################
install(FILES
digital_api.h
+ digital_impl_mpsk_snr_est.h
digital_binary_slicer_fb.h
digital_clock_recovery_mm_cc.h
digital_clock_recovery_mm_ff.h
@@ -37,12 +38,14 @@ install(FILES
digital_kurtotic_equalizer_cc.h
digital_metric_type.h
digital_mpsk_receiver_cc.h
+ digital_mpsk_snr_est_cc.h
digital_ofdm_cyclic_prefixer.h
digital_ofdm_frame_acquisition.h
digital_ofdm_frame_sink.h
digital_ofdm_insert_preamble.h
digital_ofdm_mapper_bcv.h
digital_ofdm_sampler.h
+ digital_probe_mpsk_snr_est_c.h
digital_gmskmod_bc.h
digital_cpmmod_bc.h
DESTINATION ${GR_INCLUDE_DIR}/gnuradio
diff --git a/gr-digital/include/Makefile.am b/gr-digital/include/Makefile.am
index 8ce3a94e8..3cf186d3d 100644
--- a/gr-digital/include/Makefile.am
+++ b/gr-digital/include/Makefile.am
@@ -24,6 +24,7 @@ include $(top_srcdir)/Makefile.common
# These headers get installed in ${prefix}/include/gnuradio
grinclude_HEADERS = \
digital_api.h \
+ digital_impl_mpsk_snr_est.h \
digital_binary_slicer_fb.h \
digital_clock_recovery_mm_cc.h \
digital_clock_recovery_mm_ff.h \
@@ -39,12 +40,14 @@ grinclude_HEADERS = \
digital_kurtotic_equalizer_cc.h \
digital_metric_type.h \
digital_mpsk_receiver_cc.h \
+ digital_mpsk_snr_est_cc.h \
digital_ofdm_cyclic_prefixer.h \
digital_ofdm_frame_acquisition.h \
digital_ofdm_frame_sink.h \
digital_ofdm_insert_preamble.h \
digital_ofdm_mapper_bcv.h \
digital_ofdm_sampler.h \
+ digital_probe_mpsk_snr_est_c.h \
digital_gmskmod_bc.h \
digital_cpmmod_bc.h
diff --git a/gr-digital/include/digital_impl_mpsk_snr_est.h b/gr-digital/include/digital_impl_mpsk_snr_est.h
new file mode 100644
index 000000000..df7dbadec
--- /dev/null
+++ b/gr-digital/include/digital_impl_mpsk_snr_est.h
@@ -0,0 +1,279 @@
+/* -*- 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 */
diff --git a/gr-digital/include/digital_mpsk_snr_est_cc.h b/gr-digital/include/digital_mpsk_snr_est_cc.h
new file mode 100644
index 000000000..2cbd98bab
--- /dev/null
+++ b/gr-digital/include/digital_mpsk_snr_est_cc.h
@@ -0,0 +1,115 @@
+/* -*- 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_MPSK_SNR_EST_CC_H
+#define INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H
+
+#include <digital_api.h>
+#include <gr_sync_block.h>
+#include <digital_impl_mpsk_snr_est.h>
+
+class digital_mpsk_snr_est_cc;
+typedef boost::shared_ptr<digital_mpsk_snr_est_cc> digital_mpsk_snr_est_cc_sptr;
+
+DIGITAL_API digital_mpsk_snr_est_cc_sptr
+digital_make_mpsk_snr_est_cc(snr_est_type_t type,
+ int tag_nsamples=10000,
+ double alpha=0.001);
+
+//! \brief A block for computing SNR of a signal.
+/*! \ingroup snr_blk
+ *
+ * This block can be used to monitor and retrieve estimations of the
+ * signal SNR. It is designed to work in a flowgraph and passes all
+ * incoming data along to its output.
+ *
+ * The block is designed for use with M-PSK signals especially. The
+ * type of estimator is specified as the \p type parameter in the
+ * constructor. The estimators tend to trade off performance for
+ * accuracy, although experimentation should be done to figure out
+ * the right approach for a given implementation. Further, the
+ * current set of estimators are designed and proven theoretically
+ * under AWGN conditions; some amount of error should be assumed
+ * and/or estimated for real channel conditions.
+ */
+class DIGITAL_API digital_mpsk_snr_est_cc : public gr_sync_block
+{
+ private:
+ snr_est_type_t d_type;
+ int d_nsamples, d_count;
+ double d_alpha;
+ digital_impl_mpsk_snr_est *d_snr_est;
+
+ //d_key is the tag name, 'snr', d_me is the block name + unique ID
+ pmt::pmt_t d_key, d_me;
+
+ /*! Factory function returning shared pointer of this class
+ *
+ * Parameters:
+ *
+ * \param type: the type of estimator to use \ref ref_snr_est_types
+ * "snr_est_type_t" for details about the available types.
+ * \param tag_nsamples: after this many samples, a tag containing
+ * the SNR (key='snr') will be sent
+ * \param alpha: the update rate of internal running average
+ * calculations.
+ */
+ friend DIGITAL_API digital_mpsk_snr_est_cc_sptr
+ digital_make_mpsk_snr_est_cc(snr_est_type_t type,
+ int tag_nsamples,
+ double alpha);
+
+ // Private constructor
+ digital_mpsk_snr_est_cc(snr_est_type_t type,
+ int tag_nsamples,
+ double alpha);
+
+public:
+
+ ~digital_mpsk_snr_est_cc();
+
+ int work (int noutput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items);
+
+ //! Return the estimated signal-to-noise ratio in decibels
+ double snr();
+
+ //! Return the type of estimator in use
+ snr_est_type_t type() const;
+
+ //! Return how many samples between SNR tags
+ int tag_nsample() const;
+
+ //! Get the running-average coefficient
+ double alpha() const;
+
+ //! Set type of estimator to use
+ void set_type(snr_est_type_t t);
+
+ //! Set the number of samples between SNR tags
+ void set_tag_nsample(int n);
+
+ //! Set the running-average coefficient
+ void set_alpha(double alpha);
+};
+
+#endif /* INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H */
diff --git a/gr-digital/include/digital_probe_mpsk_snr_est_c.h b/gr-digital/include/digital_probe_mpsk_snr_est_c.h
new file mode 100644
index 000000000..a78e90412
--- /dev/null
+++ b/gr-digital/include/digital_probe_mpsk_snr_est_c.h
@@ -0,0 +1,113 @@
+/* -*- 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_PROBE_MPSK_SNR_EST_C_H
+#define INCLUDED_DIGITAL_PROBE_MPSK_SNR_EST_C_H
+
+#include <digital_api.h>
+#include <gr_sync_block.h>
+#include <digital_impl_mpsk_snr_est.h>
+
+class digital_probe_mpsk_snr_est_c;
+typedef boost::shared_ptr<digital_probe_mpsk_snr_est_c> digital_probe_mpsk_snr_est_c_sptr;
+
+DIGITAL_API digital_probe_mpsk_snr_est_c_sptr
+digital_make_probe_mpsk_snr_est_c(snr_est_type_t type,
+ int msg_nsamples=10000,
+ double alpha=0.001);
+
+//! \brief A probe for computing SNR of a signal.
+/*! \ingroup snr_blk
+ *
+ * This is a probe block (a sink) that can be used to monitor and
+ * retrieve estimations of the signal SNR. This probe is designed for
+ * use with M-PSK signals especially. The type of estimator is
+ * specified as the \p type parameter in the constructor. The
+ * estimators tend to trade off performance for accuracy, although
+ * experimentation should be done to figure out the right approach
+ * for a given implementation. Further, the current set of estimators
+ * are designed and proven theoretically under AWGN conditions; some
+ * amount of error should be assumed and/or estimated for real
+ * channel conditions.
+ */
+class DIGITAL_API digital_probe_mpsk_snr_est_c : public gr_sync_block
+{
+ private:
+ snr_est_type_t d_type;
+ int d_nsamples, d_count;
+ double d_alpha;
+ digital_impl_mpsk_snr_est *d_snr_est;
+
+ //d_key is the message name, 'snr'
+ pmt::pmt_t d_key;
+
+ /*! Factory function returning shared pointer of this class
+ *
+ * Parameters:
+ *
+ * \param type: the type of estimator to use \ref ref_snr_est_types
+ * "snr_est_type_t" for details about the available types.
+ * \param msg_nsamples: [not implemented yet] after this many
+ * samples, a message containing the SNR (key='snr') will be sent
+ * \param alpha: the update rate of internal running average
+ * calculations.
+ */
+ friend DIGITAL_API digital_probe_mpsk_snr_est_c_sptr
+ digital_make_probe_mpsk_snr_est_c(snr_est_type_t type,
+ int msg_nsamples,
+ double alpha);
+
+ //! Private constructor
+ digital_probe_mpsk_snr_est_c(snr_est_type_t type,
+ int msg_nsamples,
+ double alpha);
+
+public:
+
+ ~digital_probe_mpsk_snr_est_c();
+
+ int work (int noutput_items,
+ gr_vector_const_void_star &input_items,
+ gr_vector_void_star &output_items);
+
+ //! Return the estimated signal-to-noise ratio in decibels
+ double snr();
+
+ //! Return the type of estimator in use
+ snr_est_type_t type() const;
+
+ //! Return how many samples between SNR messages
+ int msg_nsample() const;
+
+ //! Get the running-average coefficient
+ double alpha() const;
+
+ //! Set type of estimator to use
+ void set_type(snr_est_type_t t);
+
+ //! Set the number of samples between SNR messages
+ void set_msg_nsample(int n);
+
+ //! Set the running-average coefficient
+ void set_alpha(double alpha);
+};
+
+#endif /* INCLUDED_DIGITAL_PROBE_MPSK_SNR_EST_C_H */