New advanced HD Radio transmission modes for FM radio developed by Xperi could open up new revenue streams for broadcasters, create more secondary channels to target niche audiences, and enable surround sound on main channels of FM stations. Hubbard Radio completed live testing of the technology on WTLP-FM Frederick, MD (103.9) in conjunction with Xperi in early September. Although results won’t be released until November, early indicators suggest the new advanced transmission modes worked as intended.
Current HD radio modes allow 96 kilobits or 120 kilobits of digital data to be transmitted per second in conjunction with the analog FM signal. This digital data is split between the main channel audio signal and HD multicasts, as well as any transmitted traffic data services, such as those provided by iHeartMedia’s Total Traffic & Weather service and the Broadcast Traffic Consortium.
Increased digital bandwidth
The new service modes increase these speeds to 168 to 463 kilobits per second, enabling a multitude of new applications of use for broadcasters. “This will help ensure the radio’s long-term viability by allowing stations to roll out more HD subchannels or use the increased digital bandwidth in other ways,” says Dave Kolesar, Senior Broadcast Engineer at Hubbard DC. Stations could use the extra bandwidth to lease data services from third parties to send information to self-driving vehicles, such as alerting them to road closures so the vehicle can reroute automatically. As smart cities and highways become more widespread, the larger data pipeline could be used in multiple other ways. “A utility company that does not wish to maintain its own private radio system could send encrypted data to smart meters or air conditioning units, so that people who wish to register can voluntarily participate in savings programs energy,” suggests Kolesar.
As broadcasters demand more bandwidth, Xperi has proactively developed the next generation of HD FM radio service.
Under a six-month experimental license granted by the FCC, WTLP is the only station to have tested the advanced modes. The tests, which ended on September 7, transmitted WTLP’s analog and digital signal starting at 168 kilobits per second and ended with all-digital broadcasts at the maximum rate of 463 kilobits per second.
Results expected in November
The test data is currently being analyzed by Xperi and is expected to be presented at the IEEE Broadcast Symposium, November 8-10 at Kennedy Space Center in Florida. This is also when Xperi and WTLP must submit their test report to the FCC, as required by the granted experimental clearance.
“From what I observed, these new service modes worked almost exactly as Xperi engineers intended,” says Kolesar. WTLP, which simulcasts all news from the WTOP Washington news powerhouse, has proven to be an ideal testing environment for the modes due to the geography of its broadcast signal footprint. Located in western Maryland along a ridge in the Appalachian foothills, it offers a variety of transmission environments: flat plains in the east, hills and ridges with terrain shade in the west, multi-way on the ridge and concrete corridors of an urban environment in the city of Frederick itself. “I don’t have the quantitative data yet, but from what I understand, the results of the field tests closely match their expectations based on their lab tests,” says Kolesar.
Data Dissemination Opportunities
It will take time for Xperi to integrate the new HD Radio service modes into the receivers. Until then, short-term use cases for the additional bandwidth would be for applications that don’t require consumer receivers, such as smart meters and Internet of Things devices.
“Stations won’t start taking advantage of these new modes for additional audio services until there’s a critical mass of these receivers in hand,” Kolesar notes. But once that happens, the new modes would allow the launch of more sub-channels to target niche audiences with programming provided by the broadcasters or by renting the channels from third-party providers. Stations could switch to higher bitrate audio quality on their main channels and sub-channels, to enable surround sound or 3D audio.
“There are all sorts of datacasting opportunities that arise once you have more bandwidth and AM/FM radio coverage area,” says Kolesar.