Avoiding repetition [echo cancellation]
F. Bourget · Communications Engineer · 2004
After decades of playing a vital role in the circuit-switched environment, echo cancellation techniques are proving even more crucial in the IP telephony world. The worldwide adoption of the Internet has resulted in an explosion of innovative applications. This trend will continue, to the extent that carriers will be expected to support voice services in a modern network infrastructure dominated by data traffic. Although data traffic has now outstripped voice, the majority of service provider revenue still comes from traditional voice services. It is only natural that - be it on wireless or wireline networks, using circuit-switched or packet-switched technology - voice quality is today a fundamental concern for service providers. To protect this source of revenue, carriers must maintain the quality of their current voice services while they launch themselves into the mission of creating networks that will support the wave of new data offerings. A key element in ensuring voice quality on hybrid and converging networks is echo cancellation. The article looks at what echo is, where it comes from and how to cancel it. High-quality echo cancellers are bound to play a unique role in the success of future network developments.