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

Additional Inherited Members
Protected Attributes inherited from gr::digital::mpsk_snr_est
double	d_alpha
double	d_beta

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

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)

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

inline

Member Function Documentation

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

virtual

Use the register values to compute a new estimate.

Reimplemented from gr::digital::mpsk_snr_est.

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

virtual

Update the current registers.

Reimplemented from gr::digital::mpsk_snr_est.

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

• mpsk_snr_est.h