Your browser is out-of-date!

Update your browser to view this website correctly. Update my browser now


The Radio EPG Proposal Explained

Part 2 of our Series Considers a Flexible and Practical EPG Delivery Architecture Proposed for U.S. Radio Broadcasting

Last time we introduced the concept of an electronic program guide (EPG) for U.S. radio broadcasting, and the existing challenges to its implementation. This time we’ll explore some of the recommendations addressing those inherent difficulties included in a proposed Radio EPG system developed under the auspices of the NAB FASTROAD technology advocacy program. (Repeating the notice given in the previous column, the author is a consultant to this development effort.)

The development team examined a wide range of possible schemes for compilation, delivery and display of a comprehensive radio EPG, considering the entire ecosystem in its scope. Part of the team’s credentials included deep experience from the world’s only already deployed radio EPG system (in the U.K. DAB environment), providing some rare and helpful insight. Nevertheless, differences between the DAB and IBOC broadcasting models still made the U.S. effort uniquely challenging.

As is often the case, there is no single solution identified providing optimal results for all engaged sectors, but there are some likely acceptable compromises proposed that may create a successful approach.

To improve likelihood for success in this respect, a key design goal of the proposal includes maximum flexibility across multiple methods, allowing system designers, broadcasters, equipment manufacturers and consumers to choose their respective preferences while retaining interoperability. This implies a minimization of mandatory features, and a maximum of compatible options, such that the system can be quickly established yet scale adequately toward a foreseeable future where EPG provides rich, multiplatform functionality.

Of course, with any such development, ultimate success – or even initial buy-in – can only be achieved if all necessary stakeholders see a potential benefit. Thus the proposed EPG system attempts to present a balanced set of advantages for broadcasters, receiver manufacturers and consumers alike.

Four-lane highway

The proposed system identifies four methods for delivering EPG data to receivers, any or all of which could potentially operate simultaneously in any radio market.

The most “traditional” approach acts like PAD/PSD, in that each station simply transmits its own EPG information in its own IBOC datacast, using a specified portion of the HD Radio Advanced Application Services (AAS) data transmission format identified by the iBiquity EPG specification. Since in this approach, each station serves only its own purposes, the delivery model is labeled Parochial. This single EPG datastream would include scheduling information for all material broadcast on the station, however, including any multicast services.

The advantage to this approach is that it allows an EPG-cable HD Radio receiver to quickly load the currently tuned station’s EPG data (for main and all supplemental services simultaneously), but when a different station is selected, the process of loading that station’s EPG data must be repeated by the receiver. Further, if the device display were capable of showing a full-market EPG grid (as in the typical television EPG screen), the receiver would have to do all the heavy lifting of assembling and storing the EPG data from each station, one at a time, and eventually displaying the ultimate result. This will require more memory and more MIPS at the receiver, which violates one of the cardinal rules of media-format design stating that the higher-complexity requirements should always be placed at the transmit end, thus lightening the load at the receive end.

Addressing this point, a contrasting approach arranges for all stations in the market to feed their EPG data to one or more Master Stations, which carry the complete market’s EPG in their IBOC datacasts. The other stations in the market may provide a pointer to the Master Station(s), to allow receivers to know where to look for the currently tuned station’s EPG data, if it is not already in the receiver’s memory.

This allows the receiver to load the complete market’s EPG fairly quickly, and display either the full-market grid, or the currently tuned station’s data only, as the receiver allows and the user requires. To do this rapidly and seamlessly, however, the receiver will need either a second data-only tuner (as iBiquity currently envisions in its new v1.5 reference receiver design), or it will need to employ a background operation by which the receiver downloads the EPG data from the Master Stations during times when the device’s (single) tuner is not being used to listen to a station.

A variation between the two above methods is called the Shared model, which allows a number of possible configurations in which the full market’s EPG data is carried by all participating stations in the market. For example, all participating stations in the market could carry at least some data for each of the other participating stations in the market.

This would enable the receiver to quickly capture the full market’s EPG data whenever it was tuned to any station in the market. It would also not require the receiver to permanently store large amounts of data in expensive on-board RAM, since each station would continuously transmit the full market’s EPG.

(click thumbnail)
A summary of attributes for the four delivery models proposed for an HD Radio EPG system.
Making this approach more practical is a distinction between “basic” EPG data – which includes program titles and times only – versus “advanced” EPG data, which includes program descriptions and perhaps other related data, links, etc. This allows a variation in which each participating station might carry only the basic EPG data for all the other stations in the market, adding the advanced data for its own programming only.

The downside of the Shared approach is that it puts a lot of redundant data on the air in any given market, and therefore could be seen as an inefficient use of broadcast bandwidth. Nevertheless, it makes for the best user experience and most inexpensive EPG-capable receiver design.

Another variant of this approach that might make sense in some cases is a “group-centric” sharing, in which a multi-station cluster in a market selects one (or more) station(s) in the group to carry EPG data for all the other stations in the group. This could be particularly advantageous for a group’s AM stations, which have the least datacast bandwidth available, and yet might have the most EPG data to deliver, given their often highly program-oriented (e.g., news/talk, sports, ethnic, religious, etc.) formats.

Finally, any system designed today must acknowledge current and future levels of media convergence. Thus the proposed EPG ecosystem also includes a Network model, by which a radio receiver device that also includes Internet access (or potentially any other/future data connectivity method) can download market EPG data via an alternative (online) source. This would potentially allow consumers to receive radio programming schedules for an entire market from a single, central source, even on devices that do not currently include radio receivers (such as PCs, 3G phones, online gaming platforms, etc.).

Such functionality could also provide earlier EPG returns to broadcasters, considering that it will take some time for EPG-capable HD Radio receivers to proliferate in the marketplace, while online devices already exist in large and fast-growing quantities. So while this would not yet give the user the ability to directly tune to a program they find on an Internet-delivered radio EPG, it would allow listeners to find out when and where a particular program was being aired in their market, and then tune to it on any traditional radio.

In the next issue we will conclude our examination of the NAB FASTROAD Radio EPG proposal, and consider a few other challenges and opportunities that the system involves, and some details on its upcoming trials expected later this year.

Skip Pizzi is contributing editor of Radio World.

Sorry. No data so far.