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
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
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
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
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
McNamara is president of Applied Wireless, New Market,