01-02-2010, 12:12 AM
ABSTRACT
Wireless phones are increasingly being regarded as essential communications tools, dramatically impacting how people approach day-to-day personal and business communications. As new network infrastructures are implemented and competition between wireless carriers increases, digital wireless subscribers are becoming ever more critical of the service and voice quality they receive from network providers. A key technology to provide near-wireline voice quality across a wireless carrier's network is echo cancellation.
Introduction
People have been using phones as a means of distant voice communication for more than a century now.Using phones has become sort of a usual thing. We use the phones almost every day and just about every where At home,at work,outside,in our cars and so on.
Subscribers use speech quality as the benchmark for assessing the overall quality of a network. Regardless of whether or not this is a subjective judgment, it is the key to maintaining subscriber loyalty. For this reason, the effective removal of hybrid and acoustic echo inherent within the digital cellular infrastructure is the key to maintaining and improving perceived voice quality on a call. This has led to intensive research into the area of echo cancellation, with the aim of providing solutions that can reduce background noise and remove hybrid and acoustic echo before any transcoder processing. By employing this technology, the overall efficiency of the coding can be enhanced, significantly improving the quality of speech. This tutorial discusses the nature of echo and how echo cancellation is helpful in making mobile calls meet acceptable quality standards.