The Communications Research Centre has finalized a year-long research study on hybrid digital (HD) radio which will help broadcasters, policy makers and regulators evaluate the technical feasibility of this new technology for Canadian markets.

The results will provide the study's sponsors, Industry Canada and the Digital Radio Co-ordinating Group (DRCG), with a much clearer picture on any inference issues between FM in-band on-channel (IBOC) digital services and regular analog FM services operating on adjacent channels.

FM-IBOC isn't currently available in Canada; Industry Canada announced in October that it would begin accepting applications for experimental FM-IBOC transmissions. The Canadian Radio-television and Telecommunications Commission said it would be prepared to adopt an expedited licensing process for stations.

"Now that FM radio stations have been invited to experiment with HD Radio, CRC's ongoing efforts in evaluating this in-band digital technology will provide the DRCG with important data. We anticipate that this information will assist broadcasters in determining whether the new service opportunities presented by this technology will outweigh any impact on their existing analog services," says DRCG Chair Wayne Stacey.

HD radio allows existing analog stations to add-on a digital transmission component, which can provide multiple channels of programming on the same frequency without requiring additional spectrum. The technology also accommodates other features such as scrolling text and graphics content, as well as real-time traffic updates. HD radio is widely available in the United States through more than 1,500 AM and FM radio stations, although it hasn't enjoyed the level of commercial success many had anticipated.

CRC's Radio Broadcast Systems and Transmission Group is recognized worldwide for its industry leadership in the field of digital radio broadcasting, helping to position Canada as a global authority in this field. Its expertise extends to L-Band digital radio, Digital Multimedia Broadcasting and, more recently, FM-IBOC.

"Due to our in-depth expertise we've been able to develop some effective methodologies to address those test issues which we felt were weakly considered in the past. We see our work as complementing what others have done in both Canada and the United States," says André Carr, Project Leader of the Radio Broadcast Systems and Transmission (RBSC) group.

Government and industry often turn to CRC when they require objective technical advice on new technologies - advice that assists in the development of new policies, regulations and standards for efficient and effective regulation and allocation of radio spectrum.

"One of the main advantages to using CRC is that we're an impartial third party," explains René Voyer, Research Manager with CRC's RBSC group. "As a non-commercial and independent research agency, we can provide advice that is used by both the public and private sectors to make informed decisions about new technologies."

Why Canada needs independent testing

In this current study, CRC collaborated with the Canadian Broadcasting Corporation, Industry Canada's Spectrum Engineering group and Certification and Engineering Bureau, as well as Mexico's National Chamber of Radio and Television Industries (CIRT) to better predict how FM-IBOC will operate in Canadian FM radio markets.

The U.S. has studied FM-IBOC extensively, but as Carr explains, many of those results cannot be directly applied to Canada, essentially due to our different spectrum and licencing regulatory framework.

The CRC set out to conduct independent research specific to the Canadian environment. Its laboratory testing over the past year examined HD radio's basic service mode MP1 with three main objectives in mind.

One goal was to validate an upgrade to the CRC-COVLAB® - a scientific modeling software that predicts and analyzes coverage areas for various types of over-the-air communications systems. The software is widely used in government labs and engineering firms worldwide.

The CRC team had initially developed a module for the software using early technical data generated in the US to more accurately predict IBOC signal coverage and quantify the level of interference those digital transmissions will have on neighbouring analog or IBOC channels in this country. Data from field tests using an experimental transmitter the CBC had installed in Toronto in the fall of 2006 provided additional data which, combined with the current lab results, are enabling CRC to refine the IBOC module.

The second objective was to analyze the impact of FM-IBOC on existing analog FM radio signals. With so many American FM-IBOC stations so close to the Canadian border, radio stations in this country are concerned about possible interference effects. Thirdly, the team studied the overall performance of the digital FM-IBOC signal: how far does the add-on transmission reach and what service expectations can a broadcaster expect from this technology.

Carr says that the test results are being reviewed by Industry Canada and the DRCG. He did note that there are both advantages and disadvantages to the technology that would have to be considered by industry and regulators before deciding on FM-IBOC's future in Canada.

For more information on the FM-IBOC study, please contact André Carr, Project Leader, Radio Broadcast Systems and Transmission group at (613) 991-5366 or by e-mail at andre.carr@crc.gc.ca.