updated 02:07 pm EDT, Tue August 7, 2012
LTE-based calls to increase call clarity, speech bandwidth
Sprint is going to launch its HD Voice LTE service by the end of this year. The service, initially using HTC EVO 4G LTE handsets at both ends and requiring the local network to be upgraded with Network Vision, aims to improve the voice call experience by offering a wider speech bandwidth. South Korea-based SK Telecom will launch its equivalent service tomorrow, using the Samsung Galaxy S III LTE for the pilot program.
HD Voice uses the Adapted Multi-Rate Wide Band (AMR-WB) codec, an upgrade from 3G speech coding, and will use a transmission bandwidth of 23.85Kbps, double that of a 3G voice call. A wider speech bandwidth of 50-7000 Hz, compared to 3G voice call services optimized for between 300-2400 Hz, also helps to bring a claimed 40 percent improvement in voice quality.
Due to the Network Vision upgrade requirement for the networks, Sprint says it will need to upgrade a "critical mass" of its markets to support the service. After adding devices to the service other than the EVO 4G LTE, the carrier expects a significant portion of its network and devices to support HD Voice by the end of 2014.
SK Telecom, however, will begin selling the Galaxy S III LTE embedded with HD Voice from August 8, with firmware upgrades to existing Galaxy S III LTE handsets within the month, and plans to embed HD Voice as a basic feature in most of its LTE handsets in the future. The carrier completed its LTE rollout in June, covering 99 percent of the population with service in underground and in-building areas as well as mountainous and coastal regions. Going forward, three other Korean carriers will add the HD Voice service and interwork with SK Telecom to allow for cross-network HD Voice calls. [via Phone Scoop]