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itpp::FIR_Fading_Generator Class Reference

FIR type Fading generator class. More...

#include <itpp/comm/channel.h>

Inheritance diagram for itpp::FIR_Fading_Generator:
itpp::Correlated_Fading_Generator itpp::Fading_Generator

Public Member Functions

 FIR_Fading_Generator (double norm_doppler, int filter_length=500)
 Default constructor.
 
virtual ~FIR_Fading_Generator ()
 Destructor.
 
virtual void set_filter_length (int filter_length)
 Set FIR filter length.
 
virtual int get_filter_length () const
 Get filter length.
 
virtual void init ()
 Initialize the generator.
 
virtual void generate (int no_samples, cvec &output)
 Generate no_samples values from the fading process.
 
virtual void set_norm_doppler (double norm_doppler)
 Set normalized Doppler.
 
virtual void set_LOS_doppler (double relative_doppler)
 Set relative Doppler (compared to the maximum Doppler) for the LOS component.
 
virtual void set_time_offset (int offset)
 Set time offset in samples.
 
virtual double get_norm_doppler () const
 Return normalized Doppler.
 
virtual double get_LOS_doppler () const
 Get relative Doppler (compared to the maximum doppler) for the LOS component.
 
virtual double get_time_offset () const
 Get time offset in samples.
 
virtual void shift_time_offset (int no_samples)
 Shift generator time offset by a number of samples.
 
cvec generate (int no_samples)
 Generate no_samples values from the fading process.
 
void set_LOS_power (double relative_power)
 Set relative LOS power.
 
virtual void set_doppler_spectrum (DOPPLER_SPECTRUM spectrum)
 Set Doppler spectrum (for Rice fading generator)
 
virtual void set_no_frequencies (int no_freq)
 Set number of sine frequencies (for Rice fading generator)
 
virtual void set_rice_method (RICE_METHOD method)
 Set calculation method of Doppler frequencies and amplitudes (for Rice fading generator)
 
double get_LOS_power () const
 Get relative power of LOS component (Rice factor)
 
virtual DOPPLER_SPECTRUM get_doppler_spectrum () const
 Return Doppler spectrum (for Rice fading generator)
 
virtual int get_no_frequencies () const
 Get number of sine frequencies (for Rice fading generator)
 
virtual RICE_METHOD get_rice_method () const
 Get calculation method of Doppler frequencies and amplitudes (for Rice fading generator)
 

Protected Member Functions

vec Jakes_filter (double norm_dopp, int order=100)
 Jakes spectrum filter.
 
void add_LOS (int idx, std::complex< double > &sample)
 add LOS component to the sample with index idx
 

Protected Attributes

int fir_length
 Size of FIR filter.
 
int upsample_rate
 
MA_Filter< std::complex
< double >, double,
std::complex< double > > 
fir_filter
 Filter used for fading generation.
 
cvec left_overs
 Left-overs from upsampling.
 
double n_dopp
 Normalized maximum Doppler frequency.
 
double los_dopp
 Relative Doppler on LOS component (0.7 by default)
 
double time_offset
 Time offset in samples (time state in the generator)
 
bool init_flag
 signals if generator is initialized or not
 
double los_power
 Relative power of LOS component compared to diffuse component (K factor)
 
double los_diffuse
 Diffuse component: sqrt(1 / (1 + los_power))
 
double los_direct
 Direct component: sqrt(los_power / (1 + los_power))
 

Detailed Description

FIR type Fading generator class.

Author
Tony Ottosson and Adam Piatyszek

A FIR generator is a linear finite impulse response (FIR) filter implementation of a filter method for generation of a fading process. Parameters that define the generator are the normalized Doppler and length of the FIR filter. The default value of filter length is 500. If the normalized Doppler frequency is lower than 0.1 an equivalent process of a higher normalized Doppler is generated and linearly interpolated.

References:

Definition at line 536 of file channel.h.

Member Function Documentation

vec itpp::FIR_Fading_Generator::Jakes_filter ( double  norm_dopp,
int  order = 100 
)
protected

Jakes spectrum filter.

Function that generates the taps in the Jakes filter.

Parameters
orderNumber of taps in the filter
norm_doppNormalized Doppler frequency, i.e. $ f_{norm} = f_{max} T_{s} $, where $ f_{max} $ is the actual Doppler frequency and $ T_{s} $ is the sampling interval.
Returns
A vector containing the filter taps of the Jakes filter.

Definition at line 447 of file channel.cpp.

References itpp::besselj(), itpp::concat(), itpp::elem_mult(), itpp::hamming(), itpp::m_2pi, itpp::norm(), itpp::pow(), and itpp::reverse().

Referenced by init().

Member Data Documentation

int itpp::FIR_Fading_Generator::upsample_rate
protected

Upsampling rate for linear interpolation

Definition at line 559 of file channel.h.

Referenced by generate(), and init().


The documentation for this class was generated from the following files:
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