Nonintrusive Measurement of Echo-Path Parameters in VoIP Environments

This paper proposes two echo-path delay measurement methods suitable for voice-over-Internet-protocol environments, where the echo suffers from excessive delay and nonlinear distortion. The proposed methods aim at greatly reducing the computational requirements while maintaining good measurement accuracy. The delay measurement is based on the cross correlation; the computation reduction is achieved by using either downsampled speeches or sparse speeches for the two methods, respectively. The echo-path loss is also measured by using the obtained delay information. The performance under codec distortion, packet loss, noise, and double talk conditions is examined through simulations and real field measurements. The results show that the proposed methods are effective and accurate