Mobile DTV standards give content providers the ability to broadcast multiple video programs and data to mobile and vehicular devices. Although basic broadcast content is expected to be free to the user, broadcasters now have the option of combining in-the-clear content with on-demand or subscription-based pay content. But mobile DTV (MDTV) is more than just “small TV” — it opens up a world of interactive and social applications.
Integrated vs. modular
Integrated and modular systems offer options for device features and time to market. At the simplest level, an MDTV needs a compatible chipset for the tuner and video decoding. VSB modulation is used with ATSC, and COFDM is used with DVB-H; both systems use H.264/AVC for video compression. Although some chipsets provide support for a particular standard, enough commonality exists between standards that chipsets are available that support multiple standards in a cost-effective manner. These chipsets can be built into dedicated “one-way” MDTVs, which usually means more than a year of development time between product definition and market availability. The same is true for MDTV integration into a cellular phone, with an added business complexity: These devices are almost always defined and tightly controlled by cellular carriers, some of whom may look at MDTV as a competitor with their own content service business. So, although some carriers may adapt their services to include MDTV, it is not clear that all will. Nonetheless, there are also strong arguments that even 4G networks cannot fully support live broadcast to millions of simultaneous users, so MDTV could be a better solution.
One way to speed the availability of MDTV devices is to use a modular approach, in which an adapter provides a signal to an existing video-capable device. Different wired and wireless interfaces will allow MDTV services to develop as best suits the marketplace, with no one system being the end-game.
For example, several manufacturers, mostly in the Far East, have already introduced USB dongles providing MDTV support for PCs. The devices are essentially tuners only, delivering an MPEG transport stream to a host laptop or netbook PC. Software supplied with the dongle is used to view an electronic program guide (EPG), tune the receiver and decode the compressed AV stream on the fly. These same USB dongles potentially could be used with some tablets, given appropriate interfaces and driver support. Dongles dedicated for use with a certain highly popular tablet are now available.
Another solution receives MDTV signals and converts them into a Wi-Fi signal for Wi-Fi-enabled viewing devices such as laptops, PCs, tablets and smartphones. One chip manufacturer also has announced the introduction of a multi-Wi-Fi system that simultaneously serves large numbers of users, such as on public transportation trains and buses, and in private vehicles such as taxis. This would allow users to watch live TV, including local programming, without having to install any hardware or software on their personal devices.
Interactivity is the key to MDTV success. When presented with a new technology, today's consumer is not content with taking a step backward in functionality. Because consumers are now accustomed to deep interactivity with any smart device, they would find a mobile TV without similar functionality to be a rather limited experience. Mobile DTV must therefore bring a new level of capability to the broadcast medium and to the devices supporting it. The good news is that MDTV can provide support for sophisticated interactive user products.
Interactivity can be envisioned at both the local and network level. Locally, devices can offer interactive sessions by caching content that was downloaded in non-real time (NRT). In this manner, users can access more content than is available live. If downloaded by means of the OTA path, this means the device must be listening and storing whether it is idle or active. Similarly, enhanced information can be stored in the device, so that users can browse through additional content that is referenced by (and associated with) the live content, e.g., by means of live links. The key is that the enhanced content can be highly correlated with the mobile-channel video content, as well as individualized, offering a high added value to the broadcast experience.
A higher degree of interactivity can be accomplished at the network level, by combining MDTV with a return channel comprised of Wi-Fi services and/or 3G/4G cellular networks. In this way, a hybrid broadcasting network can be established that provides both an efficient return channel and maximum content bandwidth, allowing individually personalized content to reach every device. European broadcasters have already been experimenting with versions of this type of network. Because of the multiple data paths, broadcasters will be able to define different and varying levels of service by a combination of free and paid content distribution and consumption.
With a hybrid network, the devices need not always be connected to the return channel. A broadcaster uses its MDTV OTA path to broadcast content on a one-to-many basis. A combination of collective and individualized side-channel content can be pushed to the user devices, on an opportunistic basis, when the devices are “home,” i.e., when connected to the user's wireless access point. Products and services also can be developed using a commodity-leased private cellular network, potentially unbundling devices from existing mobile carriers. Linking the MDTV receiver to a user's existing smartphone could also provide a return channel. Such a configuration would find use in a car video system, for example, offering interactivity and enhanced content to backseat passengers.
The importance of personalization
The importance of user personalization should not be underestimated. When connected to the network, user behavior and preferences can be conveyed to each broadcaster (or suitable collection agent), allowing for advertising verification, as well as iterative customization of the side-channel content. A customized process can allow for correlated content to be assembled offline and pushed to the user device when an opportunistic connection is available. In addition, when the on-demand data connection is provided to the user device, the user can pull data interactively from the broadcaster when the content value is highly ephemeral.
The proliferation of software apps that provide social networking should provide an important message to the interactive MDTV operators: Users want to connect with their friends and share the entertainment experience with others. This suggests that a means for user intercommunication (e.g., texting, chats, blogs) would be a valuable feature for MDTV viewers. Of course, the availability of an interaction channel (Wi-Fi, 3G) will affect the user's socialization capability, but this can be designed into a compatible service.
Spectrum issues affect the picture, too. With the growing importance of alternate uses of spectrum, broadcasters can maximize their services to viewers by using MDTV to provide the kind of personalized and localized experience consumers are demanding in portable electronics. Some observers have even proposed using MDTV to target local sporting events, essentially making narrowcasting a part of broadcasters' product offerings. In conjunction with venue-specific wireless connectivity, and even potentially using white-space devices to complement the core content, broadcasting can take on new business models to stay competitive.
Aldo Cugnini is a consultant in the digital television industry and a partner in a mobile services company.
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