Patent ID: 6317456
Filing Date: 2001-11-13
Classification: H04B,H04L

Abstract:
A method of estimating a signal-to-noise ratio (SNR) of a signal having a signal component and a noise component, wherein the signal has been first modulated according to a predetermined modulation scheme and then demodulated by a receiver so that the signal can be represented as a complex symbol having a real part and an imaginary part, comprising the steps of:storing the complex symbol in a digital memory;accessing the digital memory to rotate the real and imaginary components of the complex symbol in a plane having an imaginary axis and a real axis until the signal components lie substantially in an upper right hand quadrant of the plane;obtaining a mean-squared value from the real part of the rotated complex symbol;obtaining a variance value from the imaginary part of the rotated complex symbol; anddividing the calculated mean-squared value by the calculated variance value to thereby obtain an estimate of the SNR of the signal.