digital: converted mpsk snr and probes to new style.

author: Tom Rondeau <trondeau@vt.edu> 2012-08-14 00:00:14 -0400
committer: Tom Rondeau <trondeau@vt.edu> 2012-08-14 00:00:14 -0400
commit: 48a95b3469febf4929c74f41beac6b33ab77566e (patch)
tree: 09fcfa18252f4e629f1bdb280b7ef0a12e1f401b /gr-digital/include
parent: 509fddb30a70862b31b0488acfbbdf523b48af0d (diff)
9 files changed, 544 insertions, 586 deletions
diff --git a/gr-digital/include/digital/CMakeLists.txt b/gr-digital/include/digital/CMakeLists.txt
index 7d8545b185..2445a6fe37 100644
--- a/gr-digital/include/digital/CMakeLists.txt
+++ b/gr-digital/include/digital/CMakeLists.txt
@@ -77,7 +77,7 @@ install(FILES
     ${digital_generated_includes}
     api.h
     glfsr.h
-#    impl_mpsk_snr_est.h
+    mpsk_snr_est.h
     additive_scrambler_bb.h
     binary_slicer_fb.h
     clock_recovery_mm_cc.h
@@ -105,7 +105,7 @@ install(FILES
     map_bb.h
 #    metric_type.h
 #    mpsk_receiver_cc.h
-#    mpsk_snr_est_cc.h
+    mpsk_snr_est_cc.h
 #    ofdm_cyclic_prefixer.h
 #    ofdm_frame_acquisition.h
 #    ofdm_frame_sink.h
@@ -116,8 +116,8 @@ install(FILES
     pfb_clock_sync_ccf.h
     pfb_clock_sync_fff.h
     pn_correlator_cc.h
-#    probe_density_b.h
-#    probe_mpsk_snr_est_c.h
+    probe_density_b.h
+    probe_mpsk_snr_est_c.h
     scrambler_bb.h
 #    simple_framer.h
 #    simple_framer_sync.h
diff --git a/gr-digital/include/digital/mpsk_snr_est.h b/gr-digital/include/digital/mpsk_snr_est.h
new file mode 100644
index 0000000000..80dad77ce3
--- /dev/null
+++ b/gr-digital/include/digital/mpsk_snr_est.h
@@ -0,0 +1,287 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011,2012 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_H
+#define INCLUDED_DIGITAL_MPSK_SNR_EST_H
+
+#include <digital/api.h>
+#include <gr_complex.h>
+
+namespace gr {
+  namespace digital {
+
+    //! 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 mpsk_snr_est
+    {
+    protected:
+      double d_alpha, d_beta;
+
+    public:
+      /*! Constructor
+       *
+       *  Parameters:
+       *  \param alpha: the update rate of internal running average
+       *  calculations.
+       */
+      mpsk_snr_est(double alpha);
+      virtual ~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 *input);
+
+      //! 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 mpsk_snr_est_simple :
+      public mpsk_snr_est
+    {
+    private:
+      double d_y1, d_y2;
+  
+    public:
+      /*! Constructor
+       *
+       *  Parameters:
+       *  \param alpha: the update rate of internal running average
+       *  calculations.
+       */
+      mpsk_snr_est_simple(double alpha);
+      ~mpsk_snr_est_simple() {}
+
+      int update(int noutput_items,
+		 const gr_complex *input);
+      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 mpsk_snr_est_skew :
+      public mpsk_snr_est
+    {
+    private:
+      double d_y1, d_y2, d_y3;
+  
+    public:
+      /*! Constructor
+       *
+       *  Parameters:
+       *  \param alpha: the update rate of internal running average
+       *  calculations.
+       */
+      mpsk_snr_est_skew(double alpha);
+      ~mpsk_snr_est_skew() {}
+
+      int update(int noutput_items,
+		 const gr_complex *input);
+      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 mpsk_snr_est_m2m4 :
+      public mpsk_snr_est
+    {
+    private:
+      double d_y1, d_y2;
+  
+    public:
+      /*! Constructor
+       *
+       *  Parameters:
+       *  \param alpha: the update rate of internal running average
+       *  calculations.
+       */
+      mpsk_snr_est_m2m4(double alpha);
+      ~mpsk_snr_est_m2m4() {}
+
+      int update(int noutput_items,
+		 const gr_complex *input);
+      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 snr_est_m2m4 :
+      public 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)
+       */
+      snr_est_m2m4(double alpha, double ka, double kw);
+      ~snr_est_m2m4() {}
+
+      int update(int noutput_items,
+		 const gr_complex *input);
+      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 mpsk_snr_est_svr :
+      public mpsk_snr_est
+    {
+    private:
+      double d_y1, d_y2;
+  
+    public:
+      /*! Constructor
+       *
+       *  Parameters:
+       *  \param alpha: the update rate of internal running average
+       *  calculations.
+       */
+      mpsk_snr_est_svr(double alpha);
+      ~mpsk_snr_est_svr() {}
+
+      int update(int noutput_items,
+		 const gr_complex *input);
+      double snr();
+    };
+
+  } /* namespace digital */
+} /* namespace gr */
+
+#endif /* INCLUDED_DIGITAL_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 0000000000..e6cc511dc7
--- /dev/null
+++ b/gr-digital/include/digital/mpsk_snr_est_cc.h
@@ -0,0 +1,96 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011,2012 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 <digital/mpsk_snr_est.h>
+#include <gr_sync_block.h>
+
+namespace gr {
+  namespace digital {
+
+    //! \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 mpsk_snr_est_cc : virtual public gr_sync_block
+    {
+    public:
+      // gr::digital::mpsk_snr_est_cc::sptr
+      typedef boost::shared_ptr<mpsk_snr_est_cc> sptr;
+
+      /*! 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.
+       */
+      static sptr make(snr_est_type_t type,
+		       int tag_nsamples,
+		       double alpha);
+
+      //! Return the estimated signal-to-noise ratio in decibels
+      virtual double snr() = 0;
+
+      //! Return the type of estimator in use
+      virtual snr_est_type_t type() const = 0;
+
+      //! Return how many samples between SNR tags
+      virtual int tag_nsample() const = 0;
+
+      //! Get the running-average coefficient
+      virtual double alpha() const = 0;
+
+      //! Set type of estimator to use
+      virtual void set_type(snr_est_type_t t) = 0;
+
+      //! Set the number of samples between SNR tags
+      virtual void set_tag_nsample(int n) = 0;
+
+      //! Set the running-average coefficient
+      virtual void set_alpha(double alpha) = 0;
+    };
+
+  } /* namespace digital */
+} /* namespace gr */
+
+#endif /* INCLUDED_DIGITAL_MPSK_SNR_EST_CC_H */
diff --git a/gr-digital/include/digital/probe_density_b.h b/gr-digital/include/digital/probe_density_b.h
new file mode 100644
index 0000000000..7459663fe1
--- /dev/null
+++ b/gr-digital/include/digital/probe_density_b.h
@@ -0,0 +1,63 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2008,2012 Free Software Foundation, Inc.
+ *
+ * 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_GR_PROBE_DENSITY_B_H
+#define INCLUDED_GR_PROBE_DENSITY_B_H
+
+#include <digital/api.h>
+#include <gr_sync_block.h>
+
+namespace gr {
+  namespace digital {
+
+    /*!
+     * This block maintains a running average of the input stream and
+     * makes it available as an accessor function.  The input stream
+     * is type unsigned char.
+     *
+     * If you send this block a stream of unpacked bytes, it will tell
+     * you what the bit density is.
+     *
+     * \param alpha  Average filter constant
+     *
+     */
+    class DIGITAL_API probe_density_b : virtual public gr_sync_block
+    {
+    public:
+      // gr::digital::probe_density_b::sptr
+      typedef boost::shared_ptr<probe_density_b> sptr;
+
+      static sptr make(double alpha);
+
+      /*!
+       * \brief Returns the current density value
+       */
+      virtual double density() const = 0;
+
+      /*!
+       * \brief Set the average filter constant
+       */
+      virtual void set_alpha(double alpha) = 0;
+    };
+
+  } /* namespace digital */
+} /* namespace gr */
+
+#endif /* INCLUDED_GR_PROBE_DENSITY_B_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 0000000000..d65e8e1b6e
--- /dev/null
+++ b/gr-digital/include/digital/probe_mpsk_snr_est_c.h
@@ -0,0 +1,94 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011,2012 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 <digital/mpsk_snr_est.h>
+#include <gr_sync_block.h>
+
+namespace gr {
+  namespace digital {
+
+    //! \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 probe_mpsk_snr_est_c : virtual public gr_sync_block
+    {
+    public:
+      // gr::digital::probe_mpsk_snr_est_c::sptr
+      typedef boost::shared_ptr<probe_mpsk_snr_est_c> sptr;
+
+      /*! Make an MPSK SNR probe.
+       *
+       *  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.
+       */
+      static sptr make(snr_est_type_t type,
+		       int msg_nsamples,
+		       double alpha);
+
+      //! Return the estimated signal-to-noise ratio in decibels
+      virtual double snr() = 0;
+
+      //! Return the type of estimator in use
+      virtual snr_est_type_t type() const = 0;
+
+      //! Return how many samples between SNR messages
+      virtual int msg_nsample() const = 0;
+
+      //! Get the running-average coefficient
+      virtual double alpha() const = 0;
+
+      //! Set type of estimator to use
+      virtual void set_type(snr_est_type_t t) = 0;
+
+      //! Set the number of samples between SNR messages
+      virtual void set_msg_nsample(int n) = 0;
+
+      //! Set the running-average coefficient
+      virtual void set_alpha(double alpha) = 0;
+    };
+
+  } /* namespace digital */
+} /* namespace gr */
+
+#endif /* INCLUDED_DIGITAL_PROBE_MPSK_SNR_EST_C_H */
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 */
diff --git a/gr-digital/include/digital_mpsk_snr_est_cc.h b/gr-digital/include/digital_mpsk_snr_est_cc.h
deleted file mode 100644
index 2cbd98bab8..0000000000
--- a/gr-digital/include/digital_mpsk_snr_est_cc.h
+++ /dev/null
@@ -1,115 +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_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_density_b.h b/gr-digital/include/digital_probe_density_b.h
deleted file mode 100644
index 271ad2a072..0000000000
--- a/gr-digital/include/digital_probe_density_b.h
+++ /dev/null
@@ -1,75 +0,0 @@
-/* -*- c++ -*- */
-/*
- * Copyright 2008,2012 Free Software Foundation, Inc.
- *
- * 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_GR_PROBE_DENSITY_B_H
-#define INCLUDED_GR_PROBE_DENSITY_B_H
-
-#include <digital_api.h>
-#include <gr_sync_block.h>
-
-class digital_probe_density_b;
-
-typedef boost::shared_ptr<digital_probe_density_b> digital_probe_density_b_sptr;
-
-DIGITAL_API digital_probe_density_b_sptr
-digital_make_probe_density_b(double alpha);
-
-/*!
- * This block maintains a running average of the input stream and
- * makes it available as an accessor function.  The input stream
- * is type unsigned char.
- *
- * If you send this block a stream of unpacked bytes, it will tell
- * you what the bit density is.
- *
- * \param alpha     Average filter constant
- *
- */
-
-class DIGITAL_API digital_probe_density_b : public gr_sync_block
-{
-private:
-  friend DIGITAL_API digital_probe_density_b_sptr
-    digital_make_probe_density_b(double alpha);
-
-  double d_alpha;
-  double d_beta;
-  double d_density;
-
-  digital_probe_density_b(double alpha);
-
-public:
-  ~digital_probe_density_b();
-
-  /*!
-   * \brief Returns the current density value
-   */
-  double density() const { return d_density; }
-
-  /*!
-   * \brief Set the average filter constant
-   */
-  void set_alpha(double alpha);
-
-  int work(int noutput_items,
-	   gr_vector_const_void_star &input_items,
-	   gr_vector_void_star &output_items);
-};
-
-#endif /* INCLUDED_GR_PROBE_DENSITY_B_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
deleted file mode 100644
index a78e904124..0000000000
--- a/gr-digital/include/digital_probe_mpsk_snr_est_c.h
+++ /dev/null
@@ -1,113 +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_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 */
author	Tom Rondeau <trondeau@vt.edu>	2012-08-14 00:00:14 -0400
committer	Tom Rondeau <trondeau@vt.edu>	2012-08-14 00:00:14 -0400
commit	48a95b3469febf4929c74f41beac6b33ab77566e (patch)
tree	09fcfa18252f4e629f1bdb280b7ef0a12e1f401b /gr-digital/include
parent	509fddb30a70862b31b0488acfbbdf523b48af0d (diff)