/* -*- c++ -*- */
/*
* Copyright 2004,2007,2011,2012 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_RECEIVER_CC_IMPL_H
#define INCLUDED_DIGITAL_MPSK_RECEIVER_CC_IMPL_H
#include <gnuradio/digital/mpsk_receiver_cc.h>
#include <gnuradio/attributes.h>
#include <gnuradio/blocks/control_loop.h>
#include <gnuradio/gr_complex.h>
#include <fstream>
#include <gnuradio/filter/mmse_fir_interpolator_cc.h>
namespace gr {
namespace digital {
class mpsk_receiver_cc_impl
: public mpsk_receiver_cc, public blocks::control_loop
{
public:
mpsk_receiver_cc_impl(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);
~mpsk_receiver_cc_impl();
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);
//! Returns the modulation order (M) currently set
float modulation_order() const { return d_M; }
//! Returns current value of theta
float theta() const { return d_theta; }
//! Returns current value of mu
float mu() const { return d_mu; }
//! Returns current value of omega
float omega() const { return d_omega; }
//! Returns mu gain factor
float gain_mu() const { return d_gain_mu; }
//! Returns omega gain factor
float gain_omega() const { return d_gain_omega; }
//! Returns the relative omega limit
float gain_omega_rel() const {return d_omega_rel; }
//! Sets the modulation order (M) currently
void set_modulation_order(unsigned int M);
//! Sets value of theta
void set_theta(float theta) { d_theta = theta; }
//! Sets value of mu
void set_mu(float mu) { d_mu = mu; }
//! 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);
}
//! Sets value for mu gain factor
void set_gain_mu(float gain_mu) { d_gain_mu = gain_mu; }
//! Sets value for omega gain factor
void set_gain_omega(float gain_omega) { d_gain_omega = gain_omega; }
//! Sets the relative omega limit and resets omega min/max values
void set_gain_omega_rel(float omega_rel);
protected:
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;
/*!
* \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;
/*!
* \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 (mpsk_receiver_cc_impl::*d_decision)(gr_complex sample) const;
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 (mpsk_receiver_cc_impl::*d_phase_error_detector)(gr_complex sample) const;
//! get interpolated value
gr::filter::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;
};
} /* namespace digital */
} /* namespace gr */
#endif /* INCLUDED_DIGITAL_MPSK_RECEIVER_CC_IMPL_H */