Conditional Access

HD Radio™

Conditional Access (CA) is a technology whereby a signal in the HD Radio™ AAS (Advanced Applications Services such as a multicast or data transmission) may be encrypted and only receivers that have been “authorized” (or entitled) will receive and decode the signal. The process has been branded as NDS Radio Guard™.

This is a two-stage process, first the signal (which may be either an audio multicast or data transmission) is encrypted (scrambled) and then each receiver, having a unique electronic serial number (ESN), may be authorized or entitled to receive the encrypted signal. The ESN is not unlike those in cellular telephones or CATV/satellite set-top boxes, and allows each receiver to be individually addressable. If the CA-capable receiver receives the correct code(s) based on the ESN, the appropriate CA channel(s) are then entitled.

Product Details

iBiquity Digital Corp is the intellectual property holder of the US IBOC system branded as HD Radio. They engaged the services of NDS to create a system for CA. NDS has extensive experience in the CATV and satellite markets for this type of technology which they have now redesigned for use in HD Radio.

Early CA-capable radios will incorporate a “chip” with the unique serial number. As more advanced HD Radio decoder chipsets become available from their manufacturers to receiver makers, that serial number will be incorporated into the main chip. Meanwhile, an existing receiver without this capability will simply not recognize a CA signal and a listener will not even know such signal exists.

If the user has a CA-capable receiver, when they tune to a CA broadcast that they are not entitled to receive, the radio will show “not authorized” and the broadcaster can have a unique message appear on the receiver’s display as to how to obtain authorization. It may be a telephone number or a web site the listener must contact. Once authorized, the display will show CA along with HD-x (where x is the HD multicast channel number) and audio plus any PSD (program service data) associated with that signal will then be available within a minute or two after the ESN is entered into the CA system at the station’s end. CA bit-rates are determined by the station and there is no impairment in audio quality as a result of CA. One or more station multicast channels may be CA. There is a single 1 kb/s of data broadcast overhead required to support the entitlements all of the CA channels on a station. The main HD-1 broadcast would not be subject to CA.

The station would require (at minimum) a Protector, which connects to the existing iBiquity compatible Importer to create a CA broadcast. The Protector provides the scrambling signals and transmits and "refreshes" receiver entitlements through the HD signal to keep CA authorized receivers “alive”. Failure to receive this signal after a certain period of time would remove access from that particular broadcast. It is interesting to note that a receiver may be authorized for multiple markets if stations so desire. For example, if all NPR stations in the State of California wished to authorize access on a “pledge free” channel for a listener who has donated at a certain level, each would authorize that ESN and the reception would be seamless throughout the state. Group broadcasters who provide a special format with CA may also do the same on a regional, statewide or national basis.

Instructions are given to the Protector by a device called the Initiator. This may be located at the station, at a headquarters location, or perhaps at a service provider who is paid by stations to operate the system. The Initiator sets up all of the Protector scrambling parameters and it also accesses the world database of CA receivers via the serial number or ESN. The radios may be authorized over one or more stations. They can be authorized for any period of time the station wishes (an hour, day, month, year, lifetime, etc.). Interconnection of Initiator, Protector, Importer and the world database is all over IP. Standard web browsers can access the Initiator over a virtual private network (with password protection). One Protector is needed for each Importer feeding an HD signal, while an Initiator may be used for one or more Protectors, as desired. Protectors and Initiators will be manufactured by NDS and sold through HD Radio equipment suppliers such as Harris Broadcast.

As stated, the CA system can operate on either audio multicast channels in HD Radio or over data transmission for such uses as subscriptions to navigation or other data uses. The same basic equipment is used at the station regardless, to create and authorize the CA. The first on-air CA broadcast used an HD-3 audio multicast and was at station WUSF-FM in Tampa, Florida commencing on March 18, 2007. This test used prototype equipment supplied by iBiquity, NDS and Harris. Similar demonstrations followed at National Association of Broadcasters the following month. Beta software was used in both the Importer and Exporter (Harris DexStar™ exciter, in this case). Commercial versions of this software are due out summer 2007 from iBiquity Digital.

Some possible utilization for CA include maintaining copyright protection of radio reading service for the blind (the subject of WUSF-HD3 broadcasts), a live concert, a pledge-free channel on public radio, a comedy channel, special sporting events (similar to pay-per-view on cable or satellite television), navigation and traffic updates as a few examples.

Commercialization of the product is expected by fall of 2007 with the first CA receivers due out in time for Holiday shopping. When available, Protectors and Initiators may be purchased through Harris Broadcast.

Please see the RELATED DOCUMENTS section in the top right corner of this page for a report on CA at the April 2007 meeting of the NRSC and a white paper provided by NDS.

HD Radio is a registered trademark of iBiquity Digital Corp.
RadioGuard is a registered trademark of NDS Limited
DexStar is a registered trademark of Harris Corp.