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A few thoughts from deep inside the VoIP industry: 1) There are "high definition" / wideband codecs that remove the traditional 3.1 KHz PCM bearer channel audi
by abalashov 11y ago
A few thoughts from deep inside the VoIP industry:
1) There are "high definition" / wideband codecs that remove the traditional 3.1 KHz PCM bearer channel audio spectrum restriction, along with its logarithmic companding, such as G.722. There is also desk handset hardware that makes them sound really, really good; given both, it's unlike any phone call you've ever had.
2) The challenge is that even in 2016, the PSTN - with its 3.1 KHz bearer channels - is still the common denominator to which nearly all audio must be reduced. So, you only stand a chance of having that kind of call quality on a private/intra-PBX type call.
3) Direct IP peering among VoIP providers hasn't really taken off, although pure-IP signalling across interconnects is becoming increasingly common. This is largely due to institutional inertia and deliberate lobbying on the part of LECs of all kinds who are invested in the incumbent per-minute revenue models and cost structures of the PSTN. (Even though the measured usage aspect is generally hidden from the end-user, the intra-industrial cost structure is not at all flat-rate.)
4) The VoLTE ambitions of mobile operators might change the game a lot as far as call quality, but there is some question as to whether the spectrum is physically there to support HD calls for all, and of course the limiting factor of mobile handsets as described in the article.
5) Residential and consumer users are probably not willing to pay for premium call quality experiences or value-added application-level features, and the VoIP industry is mostly disinterested in selling to them except through wholesale channels. But core business users - folks who still use desk phones, and who are pretty much the exclusive focus of the VoIP industry at this point - do care about this, and there's active work going on to cater to them and make their conference calls and such sound better.
6) WebRTC is overhyped and overrated, but there is one large industry to which it is directly relevant and for which it will make a significant impact: contact centres (call centres, customer service centres, support centres, etc.). Better codecs can be found there also, though somewhat offset by the varying quality of Internet connectivity and intermediate network engineering (that call centres are cheapscates is an understatement).
7) Along the lines of #4, over-the-top applications that support voice calling, such as Skype and WhatsApp, are also increasingly changing the character of the typical Millennial's "phone call", especially outside the USA. However, they are aggressively resisted by mobile carriers for obvious reasons: it commoditises them down into a dumb data pipe and purely price-level competition to provide bandwidth, while some clever Silicon Valley app takes all the value-added / higher-margin premium.
- profmonocle 11y ago> but there is some question as to whether the spectrum is physically there to support HD calls for all This surprises me. I assumed that with all the spectral efficiency gains that've been made to support higher data usage, doubling (or more) the bit rate of voice calls wouldn't be a big deal. Now I'm curious what percentage of overall data traffic on a cellular network is voice.
- abalashov 11y agoYeah, but the data usage is all asynchronous stuff, not especially delay-sensitive. It can be shipped in large packets. Voice isn't YouTube; it can't be buffered (much), so it's a hailstorm of a very large number of very small packets[1] that all have to get there in a sufficiently quick, reliable and ordered fashion as to approximate the circuit-switched experience. That changes the physical layer oversubscription economics significantly. [1] A typical "packetisation duration" in wireline VoIP is 20 ms. That's the duration of audio buffered into a single RTP frame. Edit: I'm not saying definitively that it's not physically possible to deliver high-bandwidth voice conversations for everyone as table stakes. I'm ultimately a fixed-line guy and not in a sufficient position of knowledge in wireless/RF to know that for sure. I only meant to say that there are known questions about its realism.