Networking

Peter Cochrane's Blog: VoIP reality check

It's here to stay - but there's still progress to be made

Written at home and dispatched to silicon.com from a free wi-fi node in Lower Ufford near Woodbridge, Suffolk

The entertainment industry has been chasing reality since they cut the first silent movie. At some time during their dramatic advance through technology someone cut the following maxim:

Bad picture + bad sound = Bad experience
Bad picture + good sound = Better picture perception and experience
Good picture + good sound = Excellent experience

Hollywood understood this relationship early on and it still drives the industry towards the joint goals of higher-definition pictures, special effects and surround sound. In short the entertainment industry understands that the emotional bits of communication are the most important.

You can see more about the relationship between articulation and bandwidth in the chart at the end of this blog post.

Unfortunately the much older industry of telecoms still doesn't get it. It still persists with standards that hark back to the limitations of the carbon microphone and the fixed-magnet earpiece. Roughly speaking telcos deliver a bandwidth of 300 to 3,400 hertz and a limited dynamic range of around 50 to 60 decibels, or worse. In contrast, a hi-fi music system typically spans 18 to 20,000 hertz with a dynamic rage of around 100 decibels.

A further factor in the telecoms industry is the belief that bandwidth costs money, is in some way precious and should be conserved at all costs - hence the persisting obsession with narrowband speech. This might have been true pre-1980 but since the arrival of optical fibre everything has been upturned. Today bandwidth is effectively free!

The arrival of the internet plus Skype and VoIP in general has changed everyone's perception of voice communications. Talk on a fixed-line phone and a mobile - and then try a VoIP call. They are poles apart! VoIP has near hi-fi quality with bandwidth typically spanning over 50 to 7,000 hertz but can be extended to 14k hertz and above - and all with a good dynamic range. The result is an emotional connection the like of which we never had from the telecoms industry.

For decades my engineering target for audio and video conferencing has been that they should be capable of a level of human engagement between a man and a woman that would lead them to fall in love. Well VoIP does just that! Add a good video channel and a life-size high-definition display and you have it made. The resulting combination of emotional connection might just deter people from flying or driving to that next meeting.

So is VoIP game over? Not quite! The internet is fundamentally flawed when it comes to real-time services of any kind. Raw packet switching cannot support voice or video with any degree of service quality. Additional network engineering is required to overcome the high likelihood of packet loss and overall lack of capacity.

So the bad news is today's VoIP over the internet works in two typically digital modes: brilliant and crap - and there ain't much in between. Sometimes it works well and other times it does not. The good news is that moves are afoot to fix this flaw in the internet and it is relatively easy to fix in intranets and ultimately telephone networks that move to IP.

In my view bandwidth and good quality speech and video are an absolute necessity that will transform more than the ICT industry.

human articulation v bandwidth chart

About

Peter Cochrane is an engineer, scientist, entrepreneur, futurist and consultant. He is the former CTO and head of research at BT, with a career in telecoms and IT spanning more than 40 years.