SK Telecom Launches Voice over LTE Services

­SK Telecom, a South Korean Telecom Company has launched a Voice over LTE (VoLTE) service,  branding it as “HD Voice”.

HD Voice offers high definition sound quality by using high-quality audio codec capable of handling 2.2 times wider frequency bandwidth than that of 3G voice calls. In addition to that, the call connection time is less than 0.25 to 2.5 seconds, 2 to 20 times shorter than 3G voice calls that the company says can require an average of 5 seconds to connect a call.

HD Voice uses Adapted Multi-Rate Wide Band (AMR-WB) codec, which offers upgraded 3G speech coding, and 23.85 Kbps transmission bandwidth, 2.2 times wider than that of 3G voice call, thereby transmitting the previously-inaudible low and high sound waves, and improving voice quality by a claimed 40% compared to that of 3G.

HD Voice (AMR-WB) also provides a richer and more natural speech quality due to a wider speech bandwidth of 50-7000 Hz compared to 3G voice call service that is optimized for only 300-2400 Hz voice band.

To use HD Voice, both people on a call will have to be subscribed to SK Telecom’s LTE service and have HD Voice-capable devices. The company has begun selling Galaxy S3 LTE embedded with HD Voice feature and plans to offer firmware upgrades for existing users of Galaxy S3 LTE within this month.

Going forward, high-quality voice call is expected to be realized among VoLTE customers of different carriers through service interworking among three Korean mobile carriers. In addition SK Telecom plans to embed HD Voice as a basic feature in most of its LTE smartphones to be released in the future.