HD Quality Voice Calls

[faizone 15]

Source

A growing number of mobile operators are rolling out HD voice in their networks, allowing customers with compatible phones to make calls with better voice quality. The operators have been encouraged to invest in the technology by an increase in the number of compatible phone models, according to a report from the Global Mobile Suppliers Association (GSA).

The improved voice quality is possible thanks to Adaptive Multi-Rate Wideband (AMR-WB), a speech compression algorithm that doubles the range of voice frequencies transmitted, resulting in sound comparable to FM radio according to French operator Orange.

The technology has been a slow starter. Back in 2006 Ericsson and T-Mobile announced they had conducted the first trial of the technology in a commercial network. However, in the last couple of months the technology has started to take off, in large part thanks to Orange, which has been the biggest proponent so far.

Orange has launched Mobile HD Voice in seven of the countries where it operates networks: Moldova, France, Armenia, the UK, Spain (in the Catalonia region), Belgium and Egypt (in Cairo). In 2011, Orange subscribers in Switzerland, the rest of Egypt, Luxembourg and the Dominican Republic will also be able to make calls, according to the operator.

Other operators that have added HD voice in the last three months include SFR in France, Vipnet in Croatia, Tata DOCOMO in India and Megafon in Russia, according to GSA. Telstra in Australia and 3 in the UK, as well as a number of other unnamed operators, are testing the technology, GSA president Alan Hadden said.

The growing interest among operators is helped by the availability of more phones that can make and receive HD voice calls: for the technology to work, both parties to the call must use phones and networks that support AMR-WB, according to Hadden.

At first, the Nokia 6720c was the only phone that could offer the improved sound quality. However, Orange has now added the N8 and E5 from Nokia, the Samsung Omnia 7 and the HTC Desire HD to its line-up of compatible phones. The line-up also includes the 5230 and E72 from Nokia and Sony Ericsson's Elm, the company said.

The addition of more phones, in combination with increasing awareness among operators and more public demonstrations that allow users to hear the difference should help HD voice take off on larger scale, Hadden said.

Edited December 7, 2010 by faizone

[Greatest 55]

I do not know if this is co-incidence, but a few weeks back when I had bought a new DCM connection (thanks to my crave to check out 3G speeds in their network in my city) and made a few voice calls, I was stunned to hear excellent voice on my iPhone 3GS.

I let it go from my head thinking that it might be a good feature of the handset (iPhone) that I was using, but it never came to my mind that even DCM could have to do something with this.

Now if according to the above report, DCM is the operator in India who have adopted HD voice in their network, then this must be true.

I can easily say that when I spoke from the DCM connection, I was feeling an itch that the voice clarity was as good as my rcdma connection.

I think my days of thinking, 'CDMA has excellent voice clarity than GSM' days are slowly deteriorating... way to go DCM...

[faizone 15]

Some more info...

With AMR or AMR-WB, mobile radio systems are able to use available bandwidth as effectively as possible. For example, in GSM it is possible to dynamically adjust the speech encoding rate during a session so as to continuously adapt to the varying transmission conditions by dividing the fixed overall bandwidth between speech data and error protective coding. This enables the best possible trade-off between speech compression rate and error tolerance. To perform mode adaptation, the decoder (speech receiver) needs to signal the encoder (speech sender) the new mode it prefers. This mode change signal is called Codec Mode Request or CMR.

Both codecs support voice activity detection (VAD) and generation of comfort noise (CN) parameters during silence periods. Hence, the codecs have the option to reduce the number of transmitted bits and packets during silence periods to a minimum. The operation of sending CN parameters at regular intervals during silence periods is usually called discontinuous transmission (DTX) or source controlled rate (SCR) operation. The AMR or AMR-WB frames containing CN parameters are called Silence Indicator (SID) frames.

Read the RFC here for more info

[Karthik R 246]

For the technology to work, both parties to the call must use phones and networks that support AMR-WB.

That means Tata Docomo alone implementing it wont be of much use in off-net calls

[commonman 228]

never had any voice clarity issue on CDMA

[swapnil05in 2]

so i take it this way that calls between CDMA operators & DCM will be of very good clarity.

Am I thinking right?

[faizone 15]

@Karthik..

The narrowband voice of public switched telephone network circuits operates between 300 Hz to 3.4 Khz. On the other hand, HD, or wideband, voice transmits a much wider spectrum, from 30 Hz to 7Khz which is possible only on 3G networks.. Once all operators move on to 3g, then they may look at licensing/implementing HD technology on their networks.

Also note that the consonants f, s, m and n, collectively known as fricatives, are difficult to understand via narrowband but easy to distinguish with HD voice. The same is true for foreign accents and conversation that has to compete with background noise. HD voice offers double the voice quality for typical mobile calls versus mobile narrowband. And, this greatly improved quality is accomplished without increasing capacity.

[kkdeep 6]

The narrowband voice of public switched telephone network circuits operates between 300 Hz to 3.4 Khz. On the other hand, HD, or wideband, voice transmits a much wider spectrum, from 30 Hz to 7Khz

So it uses wider spectrum and hence more bandwidth

And, this greatly improved quality is accomplished without increasing capacity.

How is it possible? Do they use some kind of compression to reduce bandwidth?