FEATURE: Mobile broadcast, more than mobile TV

Roundbox's Vinod Valloppillil argues that "mobile broadcast" should be more than just mobile TV.

Mobile TV is one of the hottest wireless applications today--and why shouldn't it be? The battle has all the elements of a great story--billions of dollars, cross-continental rivalries, fierce technological foes and, as only the cellular industry can do it, an alphabet soup of competing acronyms. Consumers love their television, and while they may not watch an hour-long episode of "Desperate Housewives," odds are that they will watch sports highlights, news, mobisodes--any on-the-go entertainment.

Lost in the buzz, however, is a broad look at the technology that's powering the hype. Is mobile TV the final application of broadcast networks like DVBH, MediaFLO, MBMS and BCMCS? Or are there other ways to leverage unique capabilities of these networks into other applications to help cover their $100 million price tags?

A growing chorus of voices are exploring the idea that broadcast technology might be about "more than mobile TV." While mobile TV certainly provides the business model anchor, nothing potentially offering a $10 ARPU lift can be ignored. There other new services which can utilize the network in unique ways. Enter "datacast."

Introducing Datacast

Datacast applications leverage the broadcast network to "push" multiple types of content to multiple subscribers simultaneously.

Many datacast applications have their genesis on the wired Internet. For example, the fabled Pointcast application achieved much fanfare in the mid-1990s but was utterly passé just a few years later. Consumers found the application's push user experience compelling and even fun. But, without an underlying datacast network to support it, network administrators loathed the massive traffic generated when thousands of consumers repetitively "polled" for the same data updates across a unicast network.

Today, many operators and device manufacturers are exploring mobile application concepts similar to Pointcast but under the guise of "Active Wallpaper" or "On-Device Portals." These applications offer promising advertising and commerce opportunities and, like their predecessor, an elegant solution to classic content navigation and discovery problems. The latest news, weather and sports headlines are always available at-a-glance with details just a click away.

Unfortunately, Active Wallpaper, like Pointcast before it, remains a classic high-concurrency application: a large number of users running it inevitably poll for the same content. Even a few hundred thousand clients (much less millions) simultaneously deploying this application destroy the economics of mobile data. Mobile broadcast provides the proper architectural solution to this problem by transmitting the data just once and allowing multiple subscribers to receive it.

The Network Revenue Equation

The flip side of the interest in datacast is the age-old problem of spectral, and thus revenue, efficiency per MHz. While a single, high-quality mobile TV channel may occupy between 200 and 300 kbps of bandwidth, individual datacast applications such as Active Wallpaper require as little as 1-10 kbps to deliver an adequate user experience. As a result, literally dozens of datacast applications can be deployed within the bandwidth normally reserved for a single TV channel.

At the same time, the discrete revenue per TV channel is notoriously difficult to ascertain. In the Cable TV world, perhaps 5-10 out of the nearly 500 channels available are able to sustain themselves on premium, per-channel pricing. The remainder are endlessly packaged and repackaged into bundled offerings with their marginal contribution unknown. By contrast, certain high-interest datacast applications--a news ticker with the latest sports news or celebrity gossip, perhaps--might be able to generate revenue on par or even exceeding a similar video channel while consuming far fewer precious airtime resources.

Datacast's Qualitative Advantages

Datacast has unique attributes which bubble up to the application layer beyond simple cost and spectral efficiency.

Retrieving data from a broadcast network is a far more passive activity for the handset relative to retrieval from unicast. As a result, datacast may have large battery life advantages and be able to support application models which require an always on network for data or event delivery.

Datacast networks also have the property of providing simultaneous delivery of content to a large number of subscribers of a channel which bypasses data/voice channels. Data is sent all at once rather than "serialized" or sent one-by-one as is the case with SMS or WAP Push.

An interesting aspect of datacast techniques is within the realm of Location Based Services (LBS). Traditional LBS applications graft location onto unicast by requiring the consumer to input zip-code-like data or use GPS chips or cell tower data to gather location information to deliver targeted data. By contrast, datacast networks--particularly cellular broadcast systems like BCMCS or MBMS--are naturally local: They flip the LBS application paradigm on its head and circumvent the privacy concerns typically associated with LBS.

Finally, datacast provides a data service with zero marginal cost. Once a datacast channel is allocated, it costs almost nothing to transmit additional data across that channel. As a result, it is now economical to bulk transmit teaser content even if only a small percentage of all recipients are "converted" into paying customers.

These attributes can be combined in unique ways. For example, datacast's natural locality, suitability for background delivery and zero marginal cost radically transforms the viability of the fabled "walk past a coffeeshop and get a coupon" scenario. Other humbler and more realistic applications might be in the realm of commercial content or mass-delivery of Super Bowl updates.

Mobile TV isn't in danger of being replaced by datacast on next generation networks like FLO, DVB-H, MBMS or BCMCS. But, it's likely that mobile TV will be asked to share at least a corner of the stage.

Vinod Valloppillil is the director of product marketing at Roundbox.