There is something fundamentally troubling about a format designed by a unilateral, proprietary group and not driven by an open standards process.
NAB 2001 provided the opportunity to see and hear the latest on IBOC digital radio. IBiquity presented demonstrations of off-air IBOC audio reception and a mock-up of what might become a video sidecar to the IBOC receiver. The latter was actually the work of Impulse Radio, which is developing a system that could use the relatively small amount of auxiliary data (including opportunistic bandwidth) in the iBiquity format to feed text and images to a Web browser-like display in IBOC receivers or IBOC-equipped vehicles.
In addition, prototype IBOC-FM receivers at NAB 2001 presented the digital signal as an enhancement feature. Users tune to a station's analog FM signal, and after a few seconds, if an adequately robust IBOC signal is available on the channel, the receiver automatically and seamlessly switches to the digital audio. An indicator illuminates when this occurs, similar to the stereo pilot light, and if multipath distortion or noise is present in the analog signal, these artifacts disappear when the IBOC light comes on. Otherwise, the audio quality stays about the same.
The user experience is like viewing a thumbnail or a progressive JPEG image on the web — it comes in small or rough at first, then resolution improves after a few seconds. In the channel-surfing world of car-radio listening, this can be considered an efficient use of the digital signal: no need to bother with long channel-acquisition time required for IBOC signal while tuning around, but once a listener decides to stay with a channel, the higher quality kicks in.
Quantity vs. quality
Downplaying the qualitative improvement of IBOC and stressing the quantitative addition of a visual component could be the right approach to sell IBOC to broadcasters, advertisers, electronics manufacturers and consumers. Broadcasters would have a potential return on conversion investments because a premium upcharge could be levied (or at least a value-add offered) for the visual display of IBOC advertising. The screen gives equipment vendors something to catch consumers' eyes and entice them to purchase.
The Impulse Radio display approach seems right, as it uses an optimized XML subset, and envisions a flexible and adaptive server method that can accommodate synchronous national and local elements in a narrowband environment. But important questions remain: 1) Will this display format be set as a standardized optional element of the IBOC specification, so authoring tools and a wide array of common content can be quickly developed? 2) Will there be enough bandwidth available to allow the system to work? To help with the latter, pre-caching of content in the receiver would be possible (or more likely, required), but the frequent channel-changing behavior of most listeners will limit the applicability of this technique.
The regulatory challenge
The iBiquity model virtually guarantees there will be no growth in the number of audio services provided by IBOC, which some discussion at the NAB 2001 Broadcast Engineering Conference suggested might be a stumbling block for regulatory approval of the format. Even if iBiquity is an appropriate system design, there is something fundamentally troubling about a digital broadcasting format designed by a unilateral, proprietary group and not driven by an open standards process.
Such an approach will favor the interests of the group producing the design; in this case, the constraint of no new audio services is an example. This serves most broadcasters' current needs. (Having gone to great expense to reduce competition via consolidation, why open the band up to more channels?) It's also the driver for most broadcast investments and recent interest in iBiquity, i.e., its defensive value in certifying that new technology will not threaten the less competitive environment that broadcasters have recently crafted. Given this mandate, iBiquity engineers seem to have accomplished their objectives (at least for FM, so far), producing a VHF-optimized, narrowband COFDM-based system that relies on an analog backup channel.
Ibiquity may represent the best technology for the job, but without an open standards process that sets requirements and defines an open specification to meet them, we will never know for sure. If the FCC rubber-stamps a format proposed by private interests, it will be neglecting due diligence and abdicating its ultimate responsibility as steward of the public interest. So while the latest IBOC-FM format is looking more marketable, it may be worth waiting a little longer for a proper, and subsequently unassailable, approval process to be set before we starting baking the silicon.