Codec interoperability
A related issue with connecting HD voice islands is interoperability between the various codecs in play, from G.722 and AMR-WB to VoIP codecs like Skype's SILK, says Jim Machi, senior VP of worldwide marketing for Dialogic.
"Interoperability is a major issue, whether it's interoperability from HD voice-enabled networks to non-HD voice-enabled networks, or from one HD voice-enabled network to another, as well as potentially from one HD voice codec to another type," Machi says. "There are infrastructure elements called gateways that would need to be installed to enable this. Or more appropriately said, there are gateways being installed every day in networks around the world, so we would need HD voice enabled gateways."
The interoperability problem also includes related value-added services like voicemail, Machi adds. "If you are on an HD voice-enabled network and you want to record a voicemail, you would want to record it in HD voice format, right? So we need media servers to be HD voice enabled."
Perhaps the biggest obstacle for enabling HD voice is the business case for it. Put simply, there isn't one - at least not if operators see HD voice as a potential new source of premium revenue.
HD voice is a hard sell, partially because of the inability to guarantee HD connections regardless of call destination, but also because not everyone can tell the difference on first listen, says Kravchenko of Spirit DSP.
"If you play narrowband and wideband voice samples for the customer, not everyone can perceive a big difference between them right away," he says. "It takes time for them to use it and get used to it, and only when they go back to narrowband do they hear the difference. So it's hard to sell HD instantly. That also means that you can't really charge more for HD voice, even for enterprise users."
The real value for HD voice, says Ericsson's Lee, is in two main areas: longer talk time (as championed by Skype above) and customer retention. "If the question is whether that translates to more ARPU, we see some doubt from the operators on that, and we haven't yet seen a successful case where the operator can generate higher ARPU directly because of HD voice."
That's not to say there won't be opportunities to put HD voice to use in creative value-added service bundles to differentiate themselves from the competition, says Lee.
"Take couples, for example - if you and your lover both subscribe to the same mobile operator, you can enjoy very intimate HD conversations with your partner over the phone," he says. "For the corporate segment, you can offer HD voice to everyone in the company, which is useful for certain businesses that really require good quality voice, like stock traders, for example. You could also use it for DTMF speech recognition services."