摘要:
Where a first communication service exhibits a first performance characteristic affecting communication quality and a second communication service exhibits both the first performance characteristic and a second performance characteristic not exhibited by the first communication service, a method for determination the effect of the second performance characteristic upon the quality of the second communication service comprising the steps: Establishing communications via the second communications service (702); Obtaining objective measures of the first performance characteristic as the second performance characteristic varies (704); Converting the objective measurement of the first performance characteristic into subjective rating based upon knowledge of the first communication service (706, 708, 710); Altering the subjective ratings to reflect the effects of the second performance characteristic by use of an assumed model for the effects of the second performance characteristic upon the subjective ratings of the first performance characteristic (712); Computing quality index values from the altered subjective ratings (712); and Adjusting the assume model to improve the correlation between the quality index values and the second performance characteristic (714)
摘要:
A method and apparatus for determining what level of performance must be maintained by a second communication service (910) so as to be perceived as being of equal quality to a first communication service, especially where the second communication service (910) is subject to additional impairments (972) not experienced by the first communication service. In one example embodiment, the present invention is applied to determining what combinations of packet loss rate (968) and packet delay are tolerable where a packet switched telephony service is desired to be perceived to be substantially equivalent to a traditional toll-quality non-packet switched telephone service. Empirically derived models (940) are used to relate user perception to objectively measurable characteristics, such as packet loss rate (968).