Patent ID: 6370120
Filing Date: 2002-04-09
Classification: H04L,H04M

Abstract:
A method of evaluating the quality of a packet-switched voice signal, the method comprising:selecting a plurality of objective characteristics for a voice connection being transmitted across a packet-switched network, at least one of the objective characteristics comprising packet loss; selecting a plurality of quality characteristics of a voice signal, each of the quality characteristics affecting the quality of the voice signal as perceived and described by users; generating a plurality of evaluation voice messages by varying selected ones of the plurality of objective characteristics for each of the evaluation voice messages; developing a transform that can be used to translate measurements of each of the objective characteristics into subjective quantifications of each of the plurality of quality characteristics; empirically acquiring user perception data by having at least one test subject listen to the evaluation voice messages and rate the quality of each evaluation voice message as one of a plurality of subjective quality ratings and also having the at least one test subject provide an overall quality opinion score of each of the evaluation voice messages; developing an effects model based on the empirically acquired user perception data, the its effects model providing perceived quality as a function of the subjective quantifications of the quality characteristics; and determining a probability that the packet-switched voice signal will fall within a selected one of the subjective quality ratings by measuring each of the objective characteristics and then translating measurements of the objective characteristics into subjective quantifications of each of the plurality of quality characteristics, the subjective quantifications being used with the effects model to determine the probability that the packet-switched voice signal will fall within a selected one of the subjective quality ratings.