Patent ID: 9621883
Date: 2017-04-11
CPC Classifications: H04B,H04N

Claim:
1. A method for evaluating a communication network that employs quadrature amplitude modulation (QAM) to transmit data, the method comprising: a) receiving from the network a communication signal modulated using a first QAM modulation format; b) demodulating the communication signal to obtain a sequence of received symbol samples; c) making hard decisions on the received symbol samples based on a first set of decision boundaries that are associated with the first QAM modulation format to obtain a sequence of modulation symbol decisions of the first modulation format corresponding to the sequence of received symbol samples; d) computing displacements of the received symbol samples with respect to the modulation symbol decisions obtained using the first set of decision boundaries; and, e) comparing the displacements of the received symbol samples obtained in step (d) to one or more decision thresholds associated with a second set of decision boundaries that are tighter than the first set of decision boundaries to obtain a measure of network performance in the absence of symbol errors for the first modulation format.