Patent ID: 9001912
Filing Date: 2015-04-07
Classification: H04B,H04L,H04N

Abstract:
1. A method of estimating a Signal-to-Noise (S/N) ratio of an input channel carrying a QAM signal, the QAM signal having a defined number of ideal values in demodulated I and Q components, the method comprising: receiving the QAM signal from the input channel; comparing decoded values from a constellation of a decoded QAM signal to ideal constellation values to determine error values for a selected group of constellation ideal values, the selected group of constellation ideal values having a fewer number of values than the defined number of ideal values for the QAM signal constellation; determining a modified Modulation Error Ratio (MER) for the input received QAM signal using error values that correspond only to the selected group of constellation ideal values; and ascribing the modified MER ratio as the S/N ratio of the input channel carrying the QAM signal.