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 int	update (int noutput_items, const gr_complex *input)
	Update the current registers. More...

virtual double	snr ()
	Use the register values to compute a new estimate. 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

alpha	the update rate of internal running average calculations.
ka	estimate of the signal kurtosis (1 for PSK)
kw	estimate 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.