The killer app for IBOC

Aug 1, 2003 12:00 PM, By Kevin McNamara, CNE

In terms of new technologies, what could we do with a couple of hundred kilohertz of spectrum? What if we could only use that spectrum to broadcast in a single direction? Trying to imagine the killer application for a service with these limitations is challenging at best. To be fair, the term killer application may be asking too much. In my world, for an application to reach true killer status, it must fill a void, address a need and most importantly, create an environment where people can work more precisely and efficiently. The last real killer application was Supercalc, the original spreadsheet program that was ultimately replaced by the more advanced Lotus and Excel. While not an application, the evolution of the Internet globally also had a similar effect.

The long road to IBOC still has no clear future on the horizon.

With the FM implementation of IBOC, standard broadcast stations will need to deal with a number of technical problems related to making IBOC work with RF propagation issues. Let’s immediately eliminate the obvious � streaming of continuous text enlightening us with the latest news, weather, sports, traffic, deer sightings, the current song, bible verses, joke of the minute, important messages and advertisements. We should have a good feel by now from radio’s last killer app, RBDS, that nobody really needs or cares about this. If someone really wants this information, it is readily available and customizable on a variety of data-enhanced pagers, cell phones, PDAs and, of course, computers. Besides, it is difficult to drive while reading textual information located somewhere in the center of your dashboard.

We like interactivity

We have been conditioned to receive a response when we type something or press a button. Media such as the Internet, digital cable, two-way paging devices and those little wireless consoles now available at many bars and restaurants (that let us prove how smart we are by answering those trivia questions) give us the interactivity we crave.

The traditional TV broadcast networks have figured this out and now we have shows where viewers can vote for something or someone in real-time and watch the results, which of course, are not shown until after the last commercial break. Where does IBOC fit into this? The problem may not lay exclusively with IBOC. While IBOC currently doesn’t permit a listener to be interactive, the real problem is that Part 73 simply doesn’t allow anyone other than the licensee to use the frequencies.

Bandwidth is essential

Whether data is traveling over the air or through a wire, the speed of data transmission has a relation to the amount of available bandwidth for a particular medium or wireless service. Creative compression techniques allow additional data to be sent within each packet, but there still will be a physical limit to the ultimate amount of data sent over a given medium. We are well aware that data transmissions over optical fiber and particularly copper mediums have limitations due to its composition and length.

Wireless services also are limited by the amount of allocated spectrum. Let’s consider the FM band to which the FCC has allocated a 20MHz segment of bandwidth that is divided into 100 channels (actually 99 in areas that have a channel 6 TV allocation) about 200kHz each. Assuming a channel was dedicated exclusively to the delivery of data, what is the maximum amount of throughput that could be expected? With a well-designed compression algorithm that provides a good degree of error correction, maybe 300kHz?

Current 2.5G PCS mobile networks can deliver average data speeds (bursts) of 19.2kb/s in two directions. While this may not seem too impressive, remember that this is while the vehicle is in motion. When stationary, some carriers claim data burst speeds of up to 128kb/s are possible. Next generation 3G and 4G wireless mobile networks may achieve data throughput in excess of 2Mb/s. Who actually needs 2Mb/s data speeds while driving or walking around town? It is funny that one of the primary benefits touted for the 3 and 4G wireless mobile networks by the wireless carriers will be their ability to broadcast video advertisements to mobile phone users � imagine, advertiser supported phone calls.

A possible killer app?

The one-way nature of terrestrial digital radio broadcasting, with or without the benefit of IBOC, will create a disadvantage over other wireless services. Assuming the FCC permitted operation that would allow two-way operation on the current allocated frequencies, or perhaps opening up some additional spectrum that might permit a degree of asymmetrical two-way communication. To efficiently process the upstream, (remote-to-base) a series of receive points (cells) would need to be established within the service area of the station. The actual amount of cells would be determined by the amount of predicted traffic, similar to that of a traditional mobile network. Under this scenario, it may be possible to operate a modified IBOC audio transmission along with a higher-speed data broadcast method. IP-enabled radios would provide the receive subsystem for listening to the broadcast, as well as contain a system that provides data receive and transmit functions. The radio may also contain a video screen and perhaps a data port that could connect a laptop to the network.

This may not be the most efficient wireless two-way data network, but it would permit a unique level of connectivity and interactivity to listeners which, if used creatively, might spark a new level of listener interaction, particularly for formats that program talk, news or sports formats.

Is something like this achievable? Yes, with the right level of government and financial support. There is a good supply of smaller towers in most areas, thanks to the growth of wireless mobile services, and it probably wouldn’t be difficult to deploy and build radio data networks that would serve one or more stations within a market.

These cells could serve a single station or the entire market; after all, the data will be riding on an IP-based network and routing that data to the appropriate station is a simple task. Once again, under this scenario each station would be broadcasting its unique IP address to all listeners; that IP address could automatically redirect a listener’s radio to send data upstream to the appropriate station.

Having a data path from each listener to the station may also allow a station to compile real-time listener patterns, as well as determine a true number of listeners and the amount of time those listeners spend with the station.

That is one possible killer application for IBOC and FM broadcasting in general. One thing is certain � the FCC will need to make drastic changes in part 73 to support the next generation of radio broadcasting.

McNamara is president of Applied Wireless, New Market, MD.