HD Voice Brings Crystal Clear Sound to Smartphones

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Many mobile carriers in Europe have begun offering HD Voice service to their customers over the past few months. Basically, this is an improvement in the quality of sound (regular conversations via call phone) which can only be offered on 3G networks. There’s also another condition for “high definition” conversations to be made possible: both phones have to support this new type of technology.

The View from AbroadAt the moment, all Nokia models support HD Voice (Nokia E5, E7, C7 etc.) while Samsung and HTC have announced support with their upcoming devices. Indeed, when both parties in a conversation use such a phone, where 3G coverage by a carrier is good, sound quality is immeasurably better compared to the classic phone conversation. It is as if you were listening to your collocutor’s voice recorded on a CD, in studio conditions, through quality headphones designed for audio enthusiasts.

None of the carriers charge for the HD Voice service, and users do not have to adjust the settings on their cell phone in order to activate the service. The conversation will automatically take place via this technology if all standards have been met.

Why the Free Upgrade?
Given the fact that users do not have to pay for this improvement in sound quality, it is logical to conclude that carriers are introducing it solely to remain competitive, i.e. in times when it is exceptionally difficult to come up with new ways of expanding the services range, differing from the rest of the market can be accomplished by raising the bar of quality when it comes to existing services. All of us can hear each other quite well when we are having a phone conversation via “regular” technology of sound transfer; however, if someone offers us better sound for free, we will definitely see it as the carrier’s advantage. Furthermore, if all cell phone manufacturers supported HD Voice, carriers would be able to turn off their 2G networks because they would no longer need to offer any of the basic services via GSM standards.

The reasons why carriers are introducing HD Voice are somewhat more complex than this, though. To understand all of them, one needs to look at the technical background of this technology. Traditional telephony is based on sampling the sound stream 8,000 times a second, and constraining the reproduction of the sound spectrum to the range between 200Hz on the low end to 3.3KHz on the high end, and fitting it into a 64Kbps bandwidth. In HD voice, a wideband codec doubles the sampling rate and more than doubles the width of the sound spectrum reproduced, from 50Hz to 7KHz. This adds significant depth and nuance to the transmitted sound — and it reduces the bandwidth requirement to 32Kbps, half that of PSTN transmission.

HD Voice technology uses Digital Signal Processing (DSP) technology to capture and transmit the higher quality sound. Several wideband codecs currently being used for HD voice include G.722 and G.722.1, and the MPEG-4 AAC Low Delay codec.

A software upgrade of the infrastructure is in question, however. Apart from 3G bandwidth, the network has to have sufficiently high capacity to handle several simultaneous HD Voice conversations on the same base station, parallel to regular data and voice traffic, for the upgrade to be feasible. As a preparation for HD Voice, the network has to be hardware optimized and upgraded in several aspects, which requires more substantial expenses than simply installing new software.

The Benefits
All of this pays off for large international carriers only, but it could be too great a risk if they were to venture out solely for their image; once the competition introduces HD Voice, this service will no longer be an advantage. The main reason why HD Voice will pay off comes down to a specific type of user being recruited who feels they will benefit from the crystal clear sound.

The best examples of such users are radio stations. Several European ones use HD Voice while reporting on location, enabling their listeners to hear direct reports of various events without interruptions (including sports matches, which take place in areas surrounded by great noise). Using HD Voice cuts down expenses and increases program technical quality, thus making sound broadcasting comparable to broadcasting HD video on television channels.

Finally, a comparison with other technologies, like video transfer. Today, we all expect that the video we are watching, whether it is on a movie screen or on television, is of HD quality. We are also used to similar standards when listening to music on our iPod or home stereo. On the other hand, when it comes to making phone calls, we settle for a standard which is several decades old, just because it is “good enough” and we’re still able to understand the person we’re talking to.

Today, 3G mobile network technology is so widespread that its not outside the realm of possibility for all of us to be making phone calls using HD Voice. While in the upcoming months, when 4G networks have become more available and their signal can be found practically anywhere, no carrier will have an excuse for poor voice transfer quality. The trend of introducing HD Voice will surely spread at the speed of light among global mobile carriers.

About Dragan Petric
For the last fifteen years, Dragan Petric (www.draganpetric.com) has been working as an IT journalist, editor and analyst, with special interests in telecommunication technologies and services. In addition, he authored five books and published over 2,500 articles in many magazines and newspapers in Europe. He has attended about 30 telecommunications and IT congresses around the world and won several journalists awards for his work. 




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