Abstract
The following case study describes how to eliminate echo in a VoIP network using delay estimation algorithms. It is known that echo with long transmission delays becomes more noticeable to users. Thus, time delay estimation, as a part of echo cancellation, is an important topic during transmission of voice signals over packetswitching telecommunication systems. An echo delay problem associated with IP-based transport networks is discussed in the following text. The paper introduces the comparative study of time delay estimation algorithm, used for estimation of the true time delay between two speech signals. Experimental results of MATLab simulations that describe the performance of several methods based on cross-correlation, normalized crosscorrelation and generalized cross-correlation are also presented in the paper.
Highlights
Echo phenomenon has been always existed in telecommunications networks
It is known that the active part of the network echo path is usually much smaller compared to the whole echo path that has to be covered by the adaptive filtering algorithm inside the echo canceller
Generalized cross-correlation algorithms, which operate in the frequency domain, are further presented
Summary
Echo phenomenon has been always existed in telecommunications networks. Generally it has been noticed on long international telephone calls. An important issue in echo analysis is the round-trip delay of the network. This is a time interval required for a signal from speaker’s mouth, across the communication network through the transmit path to the potential source of the echo, and back across the network again on the receive path to the speaker’s ear. The main problem associated with IP-based networks is that the round-trip delay can be never reduced below its fundamental limit. That is why the knowledge of the echo delay is important for using echo cancellers in packet-switching networks. There is a wide family of adaptive filtering algorithms that can exploit sparseness of the echo path to reduce high computational complexity associated with long echo paths [5,6,7,8]. Experimental results are presented in the context of the echo delay estimation which is described
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
