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What is HD voice?

Yesterday, Sprint and HTC announced the HTC Evo 4G LTE, the latest in the series of Evo phones from Sprint. While the device is largely unexceptional — information technology is only a modified version of the HTC Ane 40 that is heading to AT&T — there is a particular feature that stands out: HD voice. For the starting time fourth dimension in several years, voice calling is getting an upgrade. Just what is Hd vox and what does it offer?

Hd voice is an umbrella term which refers to technologies that enhance the quality of an audio call, or the sound portion of a video call. Depending on the calling system beingness used, HD vox may or may not be bachelor.

Most people commonly feel HD voice when using VoIP platforms like Skype on their computers. However, nearly people do not consider Skype an HD voice platform considering it is not a phone system. With the transition to predominantly digital cellular/satellite communications, as opposed to the traditional terrestrial excursion-switched telephone network, Hd vox became possible for telephony. Even better, governments effectually the world are at present considering replacing traditional excursion-switched telephone networks (POTS) with optical fiber packet-switched VoIP networks.

HTC Evo 4G LTEFor cellular (and perhaps hybrid cellular/satellite) networks, Hard disk drive voice has been in development since 2000. In the terminal two years, the specifications for Hard disk drive voice on CDMA2000, GSM, HSPA+, and LTE accept been finalized. However, this yr is the twelvemonth that device makers are finally existence offered modem chipsets (from the likes of Qualcomm) that take full back up for HD phonation.

Hd voice on CDMA2000 requires upgrading the 1X carrier to 1X Avant-garde. This new network infrastructure upgrade boosts capacity and range of a given prison cell past up to 70%, merely more than importantly it widens the 1X channel to about 300Kbps, giving more than plenty room to support a make new, higher quality audio codec. The EVRC-NW (Enhanced Variable Rate Codec – Narrowband/Wideband) codec for CDMA2000 systems is a redesigned codec that can scale from the narrowband channel sizes currently supported in CDMA2000 to new wideband channel sizes provided in CDMA2000 1X Advanced. Additionally, a multi-microphone dissonance canceling system is required to take total reward of the codec. The new codec allows for properly encoding audio in the 50Hz-4KHz range at a 16KHz sampling rate, equally opposed to half that for the older narrowband-only codec. Additionally, the wideband codec actually goes upwards to 7KHz instead of 4KHz, offer slightly better sound recording capabilities.

On the GSM side of things (which includes 2G GSM, HSPA+, and LTE), HD vox is largely a cadre network upgrade. The audio aqueduct for the base stations needs to be widened a bit to make room for the AMR-WB (Adaptive Multi-Rate Wideband) codec, though. AMR-WB and EVRC-NW offer largely the same benefits and have the same requirements. However, the HD phonation upgrade is easier on the GSM side, since no massive equipment upgrades are required at the base of operations station/tower side.

There are restrictions for currently available Hard disk phonation implementations, though. Information technology looks like the CDMA2000 and the GSM family variants of Hard disk drive vox are not interoperable for the foreseeable future, so GSM calls to CDMA phones and vice versa volition driblet down to narrowband codecs that the current interoperability systems support. For CDMA2000 networks, every participant in a call must be continued to a cell site that supports CDMA2000 1X Advanced and each handset connected to the 1X Avant-garde cells must accept a chipset supporting 1X Advanced and the new codec (otherwise it falls back to 1X and the older codec). For GSM networks, all handsets participating in the call must support the AMR-WB codec.

In LTE, HD vocalization is actually built into the VoLTE standard, because VoLTE uses AMR-WB. Equally long as the device supports AMR-WB, then Hd vocalization is possible. The but thing left would be for the network operator to enable HD voice on the network.

For wireline networks (standard telephony), HD voice is not still available. All currently available wireline telephony services (including VoIP based ones similar Vonage) use narrowband speech communication codecs, so there'south no capability for HD voice. While SIP does support it (and is the basis for VoLTE Hd voice support), most wireline networks cap the bandwidth to 12Kbps to forestall also much data from going through. Consequently, higher-quality speech codecs cannot exist used.

T-Mobile 4G coverage mapCurrently, at that place are no networks in the U.s. that offer HD voice. T-Mobile USA'south network is technically capable of it, since the new WiFi Calling feature uses the same engineering as VoLTE. However, it is not currently enabled; it will be enabled when T-Mobile deploys LTE. Sprint has declared that it will enable information technology with the upgrade to CDMA2000 1X Advanced, but it will probable be mostly useless until late 2013. It will too support Hd voice through VoLTE side by side yr. No other CDMA carriers will offer HD voice through CDMA2000 1X Advanced. Verizon Wireless and AT&T will accept support for the applied science with VoLTE deployment, but only Verizon Wireless has announced plans to offer back up for Hard disk vocalisation on LTE.

Sprint can trumpet the feature all it wants, but HD phonation will remain a useless characteristic that hardly anyone volition become to experience until late 2013 at the primeval. And even so, nearly all subscribers volition experience HD phonation through LTE, non CDMA2000 1X Advanced. If you desire to experience HD voice, try using a calculator-based VoIP solution for at present.