System and methods for measuring quality of communications over packet networks

Abstract

A communications quality measurement system for use with packet and other networks comprises a test signal transmitter, a test signal receiver, and a test signal analyzer. A test transmitter is used to produce a series of test signals selected or engineered for measuring one or more desired Quality of Service or other performance parameters of a network path to be tested. A first copy of the test signal is transmitted via a reference path of known characteristics and with minimal impairments. A second copy of the test signal is transmitted via the network path to be tested. A test receiver receives and records the signals which were carried via the reference and test paths. A test signal analyzer compares the signals received over the reference and test paths and analyzes differences to determine Quality of Service or other parameters, such as Bearer Delay, Cell or Packet Loss, Echo Delay, and Echo Amplitude, some of which are directed to the particular impairments that are characteristic of packet networks. The test signal is preferably injected into and received from handset analog audio paths of originating and terminating subscriber terminals, so that the effects of nearly all network components will be measured.