Guest Editorial – Is the HD Voice frontier creeping closer to civilization?

Written by Andrew Nicholson, Aculab Product Manger

Many in the industry have been following the adoption of HD voice growing in isolated islands amidst a sea of enterprise customers over the past few years. But as is the case with most new technology introductions, implementations, in general, have not been without concerns. Certainly, there are technical challenges facing traditional telcos that are saddled with TDM network cores that are fundamentally incompatible with HD voice. Wireless carriers, on the other hand, are expanding HD Voice field trials by using the well-defined AMR-WB standard, while VoIP service providers are sitting back, waiting for demand to achieve enough critical mass to make HD Voice a money-making proposition for them.

Skype pulled out the stops in 2010 in promoting the value of HD Voice as a conduit for clearer verbal communication resulting in longer duration calls, better customer service, and improved business efficiency and effectiveness. Its SILK codec family certainly delivers on the promise of high-clarity and less fatigue-inducing calls. Polycom, in its own right, introduced a series of HD codecs for its widely-used VoIP conference and business telephones with much the same goal in mind.

Mobile carrier trials of HD Voice may eventually lead to the end of the paradigm that mandates consumers trade call quality for mobility. The introduction of the iPad and competing tablets which support HD communications adds even more HD Voice-capable mobile endpoints. The users of these tablets tend to be early adopters who might be attracted to the ability to conduct business on-the-go without sacrificing clarity.

Bigger islands

If we consider the early adopters of HD Voice as the frontiers-folk of the current technological era, we find that they have created a series of close knit communities just like the frontier towns that crop up in any unexplored part of the world. These towns operate with relative freedom and independence from the outside world. Many enterprises have created such communities, or islands of HD service, in order to improve business efficiency or customer service.

However, as time marches on, needs and opportunities evolve, and just speaking with immediate neighbors is no longer sufficient to execute growth strategies. One must communicate with the next settlement, such as a customer in another part of the world, or the home office. At this point, the HD Voice capability and capacity of the intervening network begins to have a significant impact on success. Islands with common codec support easily create bigger islands. But, as often happens, the islands of deployment may have selected different codecs for the organic growth of their specific HD network. Or, the connection available between islands is TDM-based. The least attractive solution to either scenario is to negotiate back to the lowest common denominator – a narrow band codec that discards the highly-valued HD sound quality.

Infrastructure challenges

Telcos face the most daunting challenge to integrate HD into TDM based networks. The only real solution is to bypass TDM completely and implement IP paths to carry the native HD voice traffic. Mobile carriers can support AMR-WB in 3G and 4G networks, but the advent of VoIP over mobile networks throws a bit of a twist into the situation. Data traffic is on the rise in mobile networks, not only does the use of VoIP for HD in mobile networks raise the specter of losing ‘voice minutes’ to data traffic, the additional load on the data network can have an impact on overall performance. For a quick reality check, ask AT&T about the impact the iPhone had on its North American service in 2010.

Gateways have a long service history in telecom networks when disparate technologies or protocols must be interconnected. In the world of HD Voice, gateways can be designed to provide such interconnection, but the challenges are somewhat more complex compared to previous technologies. The SILK codecs, the Polycom SIREN codecs, G.722 (and its multiple variants) all share some basic common characteristics in sample rate and encoding frequencies, but they are generally incompatible. Transcoding gateways that can seamlessly translate between codecs will be the bridge that initially enables the HD islands to connect. With recent announcements of HD codec support, this seamless gateway capability is coming closer to reality.

Conference services

One of the more compelling cases for HD Voice is the HD conference service. Whether used for interactive meetings or webcasts, the ability for all participants to enjoy the clear sound quality of an HD conference is generally purported to be of high value. When the participants originate from many different islands, the challenge for the conference bridge developer begins to approximate that of the HD gateway designer. Terminating and transcoding from any or all of the existing HD codecs, mixing the resulting HD content, and managing the quality of the product for all participants is no simple task—impossible if the media processing platform at the base of the conference bridge cannot speak the language of the inbound lines.

Building momentum

While it is still early in the adoption phase of HD Voice, the recent acceleration of mobile field trials and the push by the likes of Skype and others to build the business case for HD Voice certainly indicates that there is growing interest for these services. Consumers appear to be ready to embrace a higher quality experience than they have settled for in the past, particularly since mobility is an expectation rather than a feature, and sound quality is becoming a critical differentiator.

The challenge will be for providers to understand the limitations that exist in terms of interoperability and seamless transport, and leverage the right resources to connect and unify every outpost.

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