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channel_model2.h
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channel_model2.h
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/* -*- c++ -*- */
/*
* Copyright 2009,2012,2013 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* SPDX-License-Identifier: GPL-3.0-or-later
*
*/
#ifndef INCLUDED_CHANNELS_CHANNEL_MODEL2_H
#define INCLUDED_CHANNELS_CHANNEL_MODEL2_H
#include <gnuradio/channels/api.h>
#include <gnuradio/hier_block2.h>
#include <gnuradio/types.h>
namespace gr {
namespace channels {
/*!
* \brief Basic channel simulator allowing time-varying frequency
* and timing inputs.
* \ingroup channel_models_blk
*
* \details
* This block implements a basic channel model simulator that can
* be used to help evaluate, design, and test various signals,
* waveforms, and algorithms.
*
* This model allows the user to set the voltage of an AWGN noise
* source (\p noise_voltage), an initial timing offset (\p
* epsilon), and a seed (\p noise_seed) to randomize the AWGN
* noise source.
*
* Multipath can be approximated in this model by using a FIR
* filter representation of a multipath delay profile with the
* parameter \p taps.
*
* Unlike gr::channels::channel_model, this block is designed to
* enable time-varying frequency and timing offsets.
* * Port 0: input signal to be run through the channel.
* * Port 1: frequency function. A constant value between -0.5 and
* 0.5 here will turn into a constant frequency offset
* from -fs/2 to fs/2 (where fs is the sample rate).
* * Port 2: timing offset function. Sets the resampling rate of
* the channel model. A constant value here produces
* that value as the timing offset, so a constant 1.0
* input stream is the same as not having a timing
* offset.
*
* Since the models for frequency and timing offset may vary and
* what we are trying to model may be different for different
* simulations, we provide the time-varying nature as an input
* function that is user-defined. If only constant frequency and
* timing offsets are required, it is easier and less expensive to
* use gr::channels::channel_model.
*/
class CHANNELS_API channel_model2 : virtual public hier_block2
{
public:
// gr::channels::channel_model2::sptr
typedef std::shared_ptr<channel_model2> sptr;
/*! \brief Build the channel simulator.
*
* \param noise_voltage The AWGN noise level as a voltage (to be
* calculated externally to meet, say, a
* desired SNR).
* \param epsilon The initial sample timing offset to emulate the
* different rates between the sample clocks of
* the transmitter and receiver. 1.0 is no difference.
* \param taps Taps of a FIR filter to emulate a multipath delay profile.
* \param noise_seed A random number generator seed for the noise source.
* \param block_tags If true, tags will not be able to propagate through this block.
*/
static sptr make(double noise_voltage = 0.0,
double epsilon = 1.0,
const std::vector<gr_complex>& taps = std::vector<gr_complex>(1, 1),
double noise_seed = 0,
bool block_tags = false);
virtual void set_noise_voltage(double noise_voltage) = 0;
virtual void set_taps(const std::vector<gr_complex>& taps) = 0;
virtual void set_timing_offset(double epsilon) = 0;
virtual double noise_voltage() const = 0;
virtual std::vector<gr_complex> taps() const = 0;
virtual double timing_offset() const = 0;
};
} /* namespace channels */
} /* namespace gr */
#endif /* INCLUDED_CHANNELS_CHANNEL_MODEL2_H */