Digital FM Radio Comes to Smartphones

Posted by Sam Churchill on

Broadcast radio is going through dramatic changes with digital technology destroying old business models as it creates new ones. Radio’s bread and butter – drive time – with local news, traffic and weather, is fading away.

It’s being replaced by satellite broadcasters like Sirius XM, personalized radio services like Pandora and Aha Radio, streaming radio stations, cellular broadcast channels like MobiTV or LTE broadcast and podcasters of all stripes. Sirius with 24M paid subscribers, is getting beaten up by Pandora’s 60 million listeners while AM radios are becoming artifacts. But radio may be coming back – on phones.

Sprint has agreed to activate an FM analog tuner in a total of some 30 million smartphones over the next three years. The Emmis NextRadio app will be preloaded on the devices thus allowing cellphone users “to hear over-the-air radio without data charges.”

The user can see album art, playlists and location-based advertising. The NextRadio app works in conjunction with the Emmis’ TagStation middleware, where the audio feed is synched with visual elements. Sprint gets a portion of this ad revenue since the radio service is free and off the air. The company hopes to rollout product this summer and other carriers are possible.

Digital FM radio on phones is a step in the right direction. No data fees. Great sound. Localized content. What’s not to like about HD Radio?

Worldwide, three main technologies are used for digital radio broadcasts: HD Radio, the “DAB Family” and Digital Radio Mondiale. They share some aspects, such as COFDM, but each also has unique characteristics driven by spectrum and regulatory constraints.

  • HD Radio is designed to work within the FM band. Digital sidebands are broadcast within the authorized spectrum mask of a 200-MHz channel alongside an analog FM signal, enabling backward compatibility with analog receivers. A variant for AM broadcasting delivers roughly half of the FM system’s data throughput within a much smaller 30 kHz occupied bandwidth.
  • The “DAB Family” includes the original DAB, DAB+ and DMB variants. Designed for deployment on VHF Band III (174–216 MHz, occupied by TV Channels 7–13 in the U.S.) or L-Band frequencies (1450–1500 MHz) for terrestrial use, all three systems package several individual services into a single 1.5-MHz “ensemble,” or multiplex. DAB uses MPEG-1 Layer 2 audio coding, DAB+ uses more efficient HE-AAC coding, and DMB supports AVC (MPEG-4) mobile video in addition to audio services.
  • Digital Radio Mondiale is currently used for shortwave and can fit more channels into a given amount of bandwidth, using various MPEG-4 codecs. Now called DRM30, it operates on SW and MW bands in standard 9- or 10 kHz channels or in wider 18 or 20 kHz allocations for increased data rate or robustness. A newer variant of the system called DRM+ offers a significantly higher data rate on 100-kHz VHF channels

In the United States, HD Radio transmits digital audio on FM stations, and is gaining new fans thanks to HD Radio receivers in cars and soon inside cell phones.

The all digital audio signal is multiplexed with analog FM. Often HD1 and HD2 are available as well as Program Associated Data (with artist, title and genre) and traffic services.

The digital transmission standard was formally adopted by the FCC in October 2002. Today, about 2,100 stations transmit HD Radio, including around 1,800 FMs, with 1,300 separate HD2 and HD3 channels. It’s still a small percentage of the 14,600 AM and FM stations in the country. HD radio receivers crossed the 1 million mark only three years ago.

Only about 2 percent of radio listeners are tuned to HD Radio channels in their cars at any given time, according to the Pew Project for Excellence in Journalism’s State of the News Media 2012 report. But automobile installations are apparently rising fast. Today some 12 million HD Radios are now in use.

According to iBiquity, which licenses the HD Radio standard, 31 automakers have now publicly announced plans to incorporate HD Radio Technology in 160+ models, and more than 80 models featuring HD Radio as standard equipment.

As the standard continues to improve, more and more features are added.

Artist Experience allows broadcasters to embed album art, station logos and other graphic content. It’s incorporated into the digital bit stream and displayed on compatible receivers with screens.

Artist Experience is like a slide show, synched to the radio stream, displaying album art and advertising. Jump2Go and Emmis TagStation have products that insert the AE content, which is multiplexed along with the HD audio signal.

Nautel’s Jump Gate reaches out to different servers for information about the music, and the actual album art image. This information is then incorporated into the Program-Associated Data.

Between 100 – 151 Kbps throughput is available, depending on the bandwidth allotted for audio services, and depends if the station is running an HD2 or HD3 program channel.

The SPS1 Audio service is already limited to 32 kbps. Images that are broadcast need to be 24 bit JPG files with a maximum of 200×200 pixels. The maximum file size should be limited to 12 kilobytes.

During commercials, it is also possible to broadcast images from sponsors, for example show the Coke logo during a Coke spot, and sell this as a value-added service. Additionally between songs or during public service shows, the radio station logo can be shown.

AM Digital Radio is under “Continued Evaluation” by the NAB. The implementation of AM digital was flawed with two incompatible standards and a lack of spectrum causing interference. The possibility of converting to 100% digital is one possibility, although that would make nearly all of today’s radios obsolete. HD Radio offers a whole range of new options for broadcasters, and many have not been thought of yet.

The ITU has approved the new H.265 standard (HEVC) for video transmission in half the bandwidth.

Radio may be “zonecast” using multiple transmitters in one community or sent over cellular channels as “Artist Enhanced” streams. LTE broadcast might enable “wireless cable”. Newspapers could “blipcast” to tablets, linking to social media.

Radio can be received by a million people simultaneously, using a single radio tower. It’s an idea whose time has come.

The economics of Over The Top streaming remain highly unfavorable for popular TV channels, with the cost in some cases hundreds of times greater than broadcast on satellite,” said Guy Bisson, research director for television at IHS Screen Digest. But for channels with a low to medium viewing share, scaling for OTT may be cheaper than satellite time. The combination of H.265 and broadcast over LTE is also expected cut the cost of video streaming dramatically.

See: TWIT: This Week in Radio Tech and Dailywireless: Radio Station Tour

Posted by Sam Churchill on Saturday, January 26th, 2013 at 5:28 pm .

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