Merge branch 'digital' of https://github.com/trondeau/gnuradio into digital

Conflicts:
	gr-digital/lib/Makefile.am
	gr-digital/python/__init__.py

1 files changed, 302 insertions, 0 deletions

diff --git a/gr-digital/include/digital_mpsk_receiver_cc.h b/gr-digital/include/digital_mpsk_receiver_cc.h
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+/* -*- c++ -*- */
+/*
+ * Copyright 2004,2007,2011 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_RECEIVER_CC_H
+#define	INCLUDED_DIGITAL_MPSK_RECEIVER_CC_H
+
+#include <digital_api.h>
+#include <gruel/attributes.h>
+#include <gri_control_loop.h>
+#include <gr_block.h>
+#include <gr_complex.h>
+#include <fstream>
+
+class gri_mmse_fir_interpolator_cc;
+
+class digital_mpsk_receiver_cc;
+typedef boost::shared_ptr<digital_mpsk_receiver_cc> digital_mpsk_receiver_cc_sptr;
+
+// public constructor
+DIGITAL_API digital_mpsk_receiver_cc_sptr 
+digital_make_mpsk_receiver_cc (unsigned int M, float theta, 
+			       float loop_bw,
+			       float fmin, float fmax,
+			       float mu, float gain_mu, 
+			       float omega, float gain_omega, float omega_rel);
+
+/*!
+ * \brief This block takes care of receiving M-PSK modulated signals
+ * through phase, frequency, and symbol synchronization.
+ * \ingroup sync_blk
+ * \ingroup demod_blk
+ *
+ * This block takes care of receiving M-PSK modulated signals through
+ * phase, frequency, and symbol synchronization. It performs carrier
+ * frequency and phase locking as well as symbol timing recovery.  It
+ * works with (D)BPSK, (D)QPSK, and (D)8PSK as tested currently. It
+ * should also work for OQPSK and PI/4 DQPSK.
+ *
+ * The phase and frequency synchronization are based on a Costas loop
+ * that finds the error of the incoming signal point compared to its
+ * nearest constellation point. The frequency and phase of the NCO are
+ * updated according to this error. There are optimized phase error
+ * detectors for BPSK and QPSK, but 8PSK is done using a brute-force
+ * computation of the constellation points to find the minimum.
+ *
+ * The symbol synchronization is done using a modified Mueller and
+ * Muller circuit from the paper:
+ * 
+ *    G. R. Danesfahani, T.G. Jeans, "Optimisation of modified Mueller
+ *    and Muller algorithm," Electronics Letters, Vol. 31, no. 13, 22
+ *    June 1995, pp. 1032 - 1033.
+ *
+ * This circuit interpolates the downconverted sample (using the NCO
+ * developed by the Costas loop) every mu samples, then it finds the
+ * sampling error based on this and the past symbols and the decision
+ * made on the samples. Like the phase error detector, there are
+ * optimized decision algorithms for BPSK and QPKS, but 8PSK uses
+ * another brute force computation against all possible symbols. The
+ * modifications to the M&M used here reduce self-noise.
+ *
+ */
+
+class DIGITAL_API digital_mpsk_receiver_cc : public gr_block, public gri_control_loop
+{
+ public:
+  ~digital_mpsk_receiver_cc ();
+  void forecast(int noutput_items, gr_vector_int &ninput_items_required);
+  int general_work (int noutput_items,
+		    gr_vector_int &ninput_items,
+		    gr_vector_const_void_star &input_items,
+		    gr_vector_void_star &output_items);
+
+
+  // Member functions related to the symbol tracking portion of the receiver
+  //! (M&M) Returns current value of mu
+  float mu() const { return d_mu;}
+
+  //! (M&M) Returns current value of omega
+  float omega() const { return d_omega;}
+
+  //! (M&M) Returns mu gain factor
+  float gain_mu() const { return d_gain_mu;}
+
+  //! (M&M) Returns omega gain factor
+  float gain_omega() const { return d_gain_omega;}
+
+  //! (M&M) Sets value of mu
+  void set_mu (float mu) { d_mu = mu; }
+  
+  //! (M&M) Sets value of omega and its min and max values 
+  void set_omega (float omega) { 
+    d_omega = omega;
+    d_min_omega = omega*(1.0 - d_omega_rel);
+    d_max_omega = omega*(1.0 + d_omega_rel);
+    d_omega_mid = 0.5*(d_min_omega+d_max_omega);
+  }
+
+  //! (M&M) Sets value for mu gain factor
+  void set_gain_mu (float gain_mu) { d_gain_mu = gain_mu; }
+
+  //! (M&M) Sets value for omega gain factor
+  void set_gain_omega (float gain_omega) { d_gain_omega = gain_omega; }
+
+protected:
+  
+  /*!
+   * \brief Constructor to synchronize incoming M-PSK symbols
+   *
+   * \param M	        modulation order of the M-PSK modulation
+   * \param theta	any constant phase rotation from the real axis of the constellation
+   * \param loop_bw	Loop bandwidth to set gains of phase/freq tracking loop
+   * \param fmin        minimum normalized frequency value the loop can achieve
+   * \param fmax        maximum normalized frequency value the loop can achieve
+   * \param mu          initial parameter for the interpolator [0,1]
+   * \param gain_mu     gain parameter of the M&M error signal to adjust mu (~0.05)
+   * \param omega       initial value for the number of symbols between samples (~number of samples/symbol)
+   * \param gain_omega  gain parameter to adjust omega based on the error (~omega^2/4)
+   * \param omega_rel   sets the maximum (omega*(1+omega_rel)) and minimum (omega*(1+omega_rel)) omega (~0.005)
+   *
+   * The constructor also chooses which phase detector and decision maker to use in the work loop based on the
+   * value of M.
+   */
+  digital_mpsk_receiver_cc (unsigned int M, float theta, 
+			    float loop_bw,
+			    float fmin, float fmax,
+			    float mu, float gain_mu, 
+			    float omega, float gain_omega, float omega_rel);
+
+  void make_constellation();
+  void mm_sampler(const gr_complex symbol);
+  void mm_error_tracking(gr_complex sample);
+  void phase_error_tracking(gr_complex sample);
+
+
+  /*!
+   * \brief Phase error detector for MPSK modulations.
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This function determines the phase error for any MPSK signal by
+   * creating a set of PSK constellation points and doing a
+   * brute-force search to see which point minimizes the Euclidean
+   * distance. This point is then used to derotate the sample to the
+   * real-axis and a atan (using the fast approximation function) to
+   * determine the phase difference between the incoming sample and
+   * the real constellation point
+   *
+   * This should be cleaned up and made more efficient.
+   *
+   * \returns the approximated phase error.
+   */
+  float phase_error_detector_generic(gr_complex sample) const; // generic for M but more costly
+
+  /*!
+   * \brief Phase error detector for BPSK modulation.
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This function determines the phase error using a simple BPSK
+   * phase error detector by multiplying the real and imaginary (the
+   * error signal) components together. As the imaginary part goes to
+   * 0, so does this error.
+   *
+   * \returns the approximated phase error.
+   */
+  float phase_error_detector_bpsk(gr_complex sample) const;    // optimized for BPSK
+
+  /*!
+   * \brief Phase error detector for QPSK modulation.
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This function determines the phase error using the limiter
+   * approach in a standard 4th order Costas loop
+   *
+   * \returns the approximated phase error.
+   */
+  float phase_error_detector_qpsk(gr_complex sample) const;
+
+
+
+  /*!
+   * \brief Decision maker for a generic MPSK constellation.
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This decision maker is a generic implementation that does a
+   * brute-force search for the constellation point that minimizes the
+   * error between it and the incoming signal.
+   *
+   * \returns the index to d_constellation that minimizes the error/
+ */
+  unsigned int decision_generic(gr_complex sample) const;
+
+
+ /*!
+   * \brief Decision maker for BPSK constellation.
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This decision maker is a simple slicer function that makes a
+   * decision on the symbol based on its placement on the real axis of
+   * greater than 0 or less than 0; the quadrature component is always
+   * 0.
+   *
+   * \returns the index to d_constellation that minimizes the error/
+   */
+  unsigned int decision_bpsk(gr_complex sample) const;
+  
+
+  /*!
+   * \brief Decision maker for QPSK constellation.
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This decision maker is a simple slicer function that makes a
+   * decision on the symbol based on its placement versus both axes
+   * and returns which quadrant the symbol is in.
+   *
+   * \returns the index to d_constellation that minimizes the error/
+   */
+  unsigned int decision_qpsk(gr_complex sample) const;
+
+private:
+  unsigned int d_M;
+  float        d_theta;
+
+  /*!
+   * \brief Decision maker function pointer 
+   *
+   * \param sample   the baseband I&Q sample from which to make the decision
+   *
+   * This is a function pointer that is set in the constructor to
+   * point to the proper decision function for the specified
+   * constellation order.
+   *
+   * \return index into d_constellation point that is the closest to the recieved sample
+   */
+  unsigned int (digital_mpsk_receiver_cc::*d_decision)(gr_complex sample) const; // pointer to decision function
+
+
+  std::vector<gr_complex> d_constellation;
+  unsigned int d_current_const_point;
+
+  // Members related to symbol timing
+  float d_mu, d_gain_mu;
+  float d_omega, d_gain_omega, d_omega_rel, d_max_omega, d_min_omega, d_omega_mid;
+  gr_complex d_p_2T, d_p_1T, d_p_0T;
+  gr_complex d_c_2T, d_c_1T, d_c_0T;
+
+  /*!
+   * \brief Phase error detector function pointer 
+   *
+   * \param sample   the I&Q sample from which to determine the phase error
+   *
+   * This is a function pointer that is set in the constructor to
+   * point to the proper phase error detector function for the
+   * specified constellation order.
+   */
+  float (digital_mpsk_receiver_cc::*d_phase_error_detector)(gr_complex sample) const;
+
+
+  //! get interpolated value
+  gri_mmse_fir_interpolator_cc 	*d_interp;
+  
+  //! delay line length.
+  static const unsigned int DLLEN = 8;
+  
+  //! delay line plus some length for overflow protection
+  __GR_ATTR_ALIGNED(8) gr_complex d_dl[2*DLLEN];
+  
+  //! index to delay line
+  unsigned int d_dl_idx;
+
+  friend DIGITAL_API digital_mpsk_receiver_cc_sptr
+  digital_make_mpsk_receiver_cc (unsigned int M, float theta,
+				 float loop_bw,
+				 float fmin, float fmax,
+				 float mu, float gain_mu, 
+				 float omega, float gain_omega, float omega_rel);
+};
+
+#endif