This is one in a series about global trends in radio.
David Layer is vice president, advanced engineering at the National Association of Broadcasters in the United States. He’s a specialist in technical standards-setting and development of regulatory frameworks for terrestrial digital broadcasting technologies in the U.S., and he is a frequent presenter at broadcasting industry events in the U.S. and abroad.
Radio World: David, when you look at the state of radio around the world, what would you say are the most important macro changes in transmission and technology platforms?
David Layer: There are a number of important changes taking place.
The development of cloud service platforms for radio broadcasters is a positive development for radio, bringing new options for radio station operation that can shift costs from capital expenses to operating expenses. Cloud-based services also provide simplified and enhanced redundancy, improving the robustness of station operations especially during times of emergency or extreme weather.
Outside the U.S., digital radio appears to be gaining ground, with DAB+ and DRM making inroads into previously unserved markets and, for DRM, continued interest in developing receiver implementations.
This is a positive development as digital radio services offer improved performance and expanded content choices for listeners.
NAB continues to be a strong advocate for both digital radio and AM/FM radio in the U.S. and is encouraged by the recent positive movement of the “AM Radio for Every Vehicle Act” in the U.S. Congress.
RW: We’ve seen a few instances where countries have tried to move away from FM broadcasting. Do you feel this trend will accelerate?
Layer: In the U.S., FM radio is a tremendously successful service with a huge installed receiver base. Norway is the sole place where a bona fide switch-off has occurred, and even there, FM radio is still in use by local radio stations. Countries like Switzerland and the U.K. have been discussing the possibility of a switch-off for a long time, but any possible switch-off dates keep getting moved back.
Switch-off is less of an issue in the U.S. since our digital radio system, HD Radio, allows analog and digital signals to coexist, unlike the European digital radio system DAB+, where analog and digital signals exist in separate frequency bands.
The emergence of hybrid radio services — over-the-air broadcast combined with mobile broadband-delivered content — is giving analog services like FM a new “lease on life” as hybrid radio joins the economy of broadcast audio delivery with the advanced metadata and personalized content delivery of the internet.
Analog AM radio in particular can benefit from a good hybrid radio implementation as analog AM has no native metadata capability. On a hybrid radio receiver, though, AM stations look and feel exactly the same as more advanced digital radio and streaming audio services.
I believe that hybrid radio has the potential to give analog radio services enhanced relevance in a digital world, a good thing for radio. But hybrid radio should be viewed as a complement to, not a replacement for digital radio.
RW: Can you expand on that?
Layer: Hybrid radio platforms bring a host of benefits to listeners and broadcasters. Listeners enjoy the rich metadata descriptions of content as well as expanded choices offered by the internet. Broadcasters for the first time have a real interactive service at scale, which helps in a number of ways, perhaps most importantly in the ability to get detailed analytical information on who is listening, their content choices and where this listening is occurring.
On the other hand, hybrid radio receiver penetration in the marketplace takes time to grow. Currently in the U.S. there are on the order of 10 million hybrid radio receivers on the DTS Autostage platform. Broadcasters need to recognize that there are 10 times that many digital radio receivers, and that a digital radio signal can provide the rich metadata and additional content choices that listeners want.
More U.S. broadcasters should consider implementing digital radio. Hybrid radio should be viewed as a complement to digital, not a replacement.
RW: Will broadcasting itself still be relevant in the long term?
Layer: Absolutely. Radio broadcasting has been proven time and again to be a sought-after and resilient service in the face of competition from new technology. Furthermore, radio offers emergency alerting capabilities that are unmatched by any other service and necessary for the public safety.
Alerting capabilities aside, audio services that utilize mobile broadband for delivery are perhaps the fiercest rivals radio has ever faced, and it’s more important than ever that radio broadcasters provide the compelling local content listeners seek. Making good use of digital and hybrid radio technologies is important, too, and broadcasters that do these things will be best positioned to remain as relevant as they have always been.
RW: Are there implications for radio stations in the rollout of ATSC 3.0 broadcasting in the United States?
Layer: There have been some limited experiments in providing audio services over ATSC 3.0 signals. With its high digital capacity (typically in the 20–30 Mbps range), a single ATSC 3.0 transmission can accommodate dozens if not hundreds of audio channels, similar to what is delivered by other digital satellite services.
However, widespread deployment of audio services over ATSC 3.0 will likely depend on the availability and adoption of portable and mobile receivers equipped with ATSC 3.0 chipsets. Until such devices achieve meaningful market penetration, large-scale rollout of radio-style services over ATSC 3.0 appears unlikely.
RW: Has software-defined radio technology played a role in how radio listening is evolving?
Layer: Software-defined radio (SDR) architectures have been instrumental in supporting the proliferation of digital radio, since a single hardware platform can be used to support multiple digital radio technologies.
Unlike analog AM and FM, which are used worldwide, there are multiple digital radio standards in use including HD Radio (primarily in North America), DAB+ (primarily Europe and Australia), DRM (used most extensively in India and recently adopted for use in China), ISDB (a Japanese-developed system also used in Brazil), and Convergent Digital Radio (CDR, also called China Digital Radio) used in the FM band in China.
Given these multiple, incompatible systems, the ability to use SDR-based receivers is critical to the affordable implementation of digital radio, especially for receivers in automobiles which are designed for global markets.
SDR technology is beneficial for legacy AM and FM systems, as well.
As an example, the National Radio Systems Committee’s AM Improvement Working Group (AIWG) has been conducting research and experimentation on advanced filtering and noise suppression algorithms to improve the listenability of AM radios that rely upon SDR receiver implementations.
Work being done by the AIWG regarding the use of co-channel AM boosters (working in conjunction with a full-service AM station to create a single-frequency network) suggests that the synchronous AM detectors used in SDR AM receivers will be less susceptible to the RF interference that exists in the SFN “mush zones” than are the more traditional AM envelope detector circuits.
Read more on this topic in the free ebook “Global Radio Update.”
