GNU Radio Manual and C++ API Reference  3.10.9.1
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gr::digital::snr_est_m2m4 Class Reference

SNR Estimator using 2nd and 4th-order moments. More...

#include <gnuradio/digital/mpsk_snr_est.h>

Public Member Functions

 snr_est_m2m4 (double alpha, double ka, double kw)
 
 ~snr_est_m2m4 () override
 
int update (int noutput_items, const gr_complex *input) override
 Update the current registers. More...
 
double snr () override
 Use the register values to compute a new estimate. More...
 
- Public Member Functions inherited from gr::digital::mpsk_snr_est
 mpsk_snr_est (double alpha)
 
virtual ~mpsk_snr_est ()
 
double alpha () const
 Get the running-average coefficient. More...
 
void set_alpha (double alpha)
 Set the running-average coefficient. More...
 
virtual double signal ()
 Returns the signal power estimate. More...
 
virtual double noise ()
 Returns the noise power estimate. More...
 

Additional Inherited Members

- Protected Attributes inherited from gr::digital::mpsk_snr_est
double d_alpha
 
double d_beta
 
double d_signal
 
double d_noise
 

Detailed Description

SNR Estimator using 2nd and 4th-order moments.

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.

Constructor & Destructor Documentation

◆ snr_est_m2m4()

gr::digital::snr_est_m2m4::snr_est_m2m4 ( double  alpha,
double  ka,
double  kw 
)

Constructor

Parameters:

Parameters
alphathe update rate of internal running average calculations.
kaestimate of the signal kurtosis (1 for PSK)
kwestimate of the channel noise kurtosis (2 for AWGN)

◆ ~snr_est_m2m4()

gr::digital::snr_est_m2m4::~snr_est_m2m4 ( )
inlineoverride

Member Function Documentation

◆ snr()

double gr::digital::snr_est_m2m4::snr ( )
overridevirtual

Use the register values to compute a new estimate.

Reimplemented from gr::digital::mpsk_snr_est.

◆ update()

int gr::digital::snr_est_m2m4::update ( int  noutput_items,
const gr_complex input 
)
overridevirtual

Update the current registers.

Reimplemented from gr::digital::mpsk_snr_est.


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