Enhanced HD voice for LTE takes voice quality to the next level in LTE/VoLTE and Wi-Fi networks, as T-Mobile launches first commercial service in the US with support from Ericsson.
Ericsson evolved HD Voice

In the app-centric world of modern smartphones, it’s easy to lose sight of progress in phones’ core function – voice services. But that’s changing with the introduction of Evolved HD voice for LTE, now entering the market and bringing greatly improved audio quality and reliability for voice and music within calls.

To evolve HD voice services further is enabled with the Enhanced Voice Service (EVS) next-generation audio codec, standardized in 3GPP for VoLTE/LTE networks. This improves the quality of voice and music within calls beyond today’s narrowband voice and HD voice services (which is already deployed in many 2G, 3G and LTE networks).

T-Mobile has pioneered commercial EVS services in the Unites States. With Ericsson’s support, T-Mobile provides nationwide EVS support for VoLTE and Wi-Fi calling users, delivering even greater audio quality than current HD voice services, and better call reliability and quality across both T-Mobile’s LTE network and Wi-Fi access.

Mark McDiarmid, Vice President Radio Network Engineering and Development at T-Mobile says: “With Ericsson’s partnership, we’ve been able to bring better voice reliability and higher fidelity calls to T-Mobile customers in more times and places than HD voice alone could provide. We already have three EVS-capable devices in the market and will have seven by the end of the year.”

Phones have always been about bringing people together, but for much of their history, they have been capable of carrying only a limited part of the human voice’s dynamic range. When mobile phones first launched in the 1980s and smartphones in the 1990s, they supported only narrowband voice capabilities. HD voice (wideband voice capabilities) finally debuted on 3G networks in 2009, then on 2G a few years later, and was extended to LTE in 2012. But now, with Enhanced HD voice expanding the available audio spectrum even beyond HD, callers will feel like they are standing next to each other

Ericsson has been one of the main contributors to EVS standards development within 3GPP, along with 11 other companies, including network vendors, device and chipset vendors, technology companies, and operators. Ericsson demonstrated EVS in public for the first time at Mobile World Congress 2014, and the first operator trials followed.

To achieve more natural voice and better quality music within calls, EVS brings together new codec support in the device’s chipset and software, and adaptions of the acoustic design of phones (such as ensuring that microphones and speakers are capable of covering the expanded audio frequency range). Commercial device support for EVS is already strong – major chipset vendors support it now, which means that several device vendors have started enabling this on commercial phones.

Mobile networks also need to be updated with new software in the IMS core network to support EVS. The Ericsson Session Border Gateway (SBG) and the Ericsson Media Resource System (MRS) include this new functionality.

For users, Enhanced HD voice brings significantly improved HD voice quality, excellent in-call music quality, and even the possibility for stereo sound in the future. In particular, users will enjoy better quality audio in areas with limited LTE coverage and more robust voice services on networks prone to packet loss and jitter.

The improved audio quality and service reliability of Enhanced HD voice also means clearer on-hold music, announcements, and voicemail. It also opens the door for innovative new uses, such as customized ring-back tones, sharing live music over voice calls, and others that will emerge as people explore the possibilities of the new technology.

For operators, the globally interoperable, standards-based technology delivers telecom-grade quality using the same bandwidth as HD voice. Enhanced HD voice enables operators to provide more attractive and high-quality voice services (bundled with LTE data subscriptions) for consumers and enterprise users. The marketing name of this new service towards consumers is yet to be defined by the market.

With Enhanced HD voice available on commercial VoLTE and Wi-Fi calling networks, mobile phone subscribers can now hear the full dynamic range of the human voice in calls for the first time in the history of mobile phones. Smartphone calls can now make people feel as though they are standing next to each other – and the benefits are crystal clear.