DRM not inferior but complimentary says Ruxandra Obreja

The expansion of digital radio to regional areas in Australia’s vast continent is an issue that has been challenging broadcasters and regulators for some time.

While DAB+ has been highly successful in Australia’s main population centres, its expansion to the rest of the country has slowed due to cost, technology and frequency issues.

Some of the submissions to the recent ACMA consultation on the Future of Radio revived discussion on the possibility of using DRM to solve some digital radio coverage issues in regional Australia.

CRA dismissed DRM, saying in its submission:

The Issues Paper notes the existence of an alternative digital technology, DRM. This is not a viable technological option in Australia, given that so much investment and infrastructure has been built around DAB+ technology… DAB+ is not yet able to reproduce the coverage offered by AM and FM and therefore must continue to develop alongside the existing analogue solutions.

Other submissions however, were more open to further consideration of DRM.

Broadcast Australia’s submission said:

Whilst VHF-FM and VHF-DAB+ cannot provide similar coverage to the MF-AM radio service, two existing technologies have the ability to provide similar reach – satellite and Digital Radio Mondiale (DRM) in the MF band.

The satellite systems available for provision of radio to in-home, mobile and portable receivers rely on multiple satellites and numerous terrestrial in-fill transmitters. As such, satellite delivered radio is unlikely to be commercially viable in the Australian environment.

DRM in the MF band does, however, warrant further detailed investigation and BA would be willing to engage with industry parties on this investigation, including conducting system trials… further work is required to determine the feasibility of these technologies and, in the case of DRM, the availability of receivers capable of working in this spectrum.

SBS recommends further consideration of DRM, as does the CBAA:

While there is no obvious successor technology available to be immediately deployed, SBS recommends further consideration be given to a number of options to replace AM, with a focus on Digital Radio Mondiale (DRM); and emerging satellite technologies.

The CBAA supports the ACMA facilitating early stage exploration and trial, in the existing VHF-FM band, of VHF-DRM free-to-air digital radio services.

Technologist Alan Hughes made two submissions with a high level of technical detail (See here and here). He is supportive of the success of DAB+ in high population centres, but also proposes the use of DRM in low population areas of regional Australia:

DAB+ has been left with 8 DAB+ transmission channels which cannot be reused within 336 km for high power transmissions.  DAB+ has been designed for areas of high population density because we are using it for up to 29 programs requiring a number of broadcasters to spread the costs…

By comparison Digital Radio Mondiale is designed for single broadcasters who can transmit their AM and supplementary FM program from a single transmitter which can be located closest to the population centre of the licence area. The large number of transmission channels available remakes planning much easier. All DRM radios contain a screen to which will display images and Jounaline text.

Ruxandra Obreja, the Chair of the Digital Radio Mondiale Consortium made a submission (see it in full here), and also read radioinfo’s submission carefully, taking issue with some of our views on DRM for Australia.

Ruxandra’s comments on our submission are below:

radioinfo said:
The alternative digital transmission standard DRM (Digital Radio Mondiale) has previously been considered for Australia and rejected, but still continues to be discussed at times.

Ruxandra replied:
It was not rejected, it was thrown out with the bathwater when SW was discontinued, one of the reasons ACMA has started this very consultation.

radioinfo said:
DRM could be a solution for regional areas in this vast continent, but that would require a change to legislation and a significant amount of thinking about receivers.

Ruxandra countered:
Nor sure what legislative changes are required. As DRM uses more or less the current planning parameters, these changes would be minimal.

Not so much thinking about receivers needed either, as DRM-DAB+ chipsets exist and receiver solutions, too. Have you seen the recent Silabs announcement (Silabs being the largest chipset manufacturer in the world) to add DRM for FM to their comprehensive board?

radioinfo said:
While DRM is an inferior system to DAB+ when operated in simulcast, it could be a cost effective way for some stations to digitize their regional transmissions and deliver some supplementary digital benefits, without the extra cost of new transmission facilities.
Ruxandra said:
DRM is not inferior, it is ITU recommended, as is DAB/DAB+, and it can be used for different purposes and coverage needs, that is all. DRM is the only all-bands open standard for local and large coverage.

We could split hairs and say that technically simulcasting is not available in DAB, a very local (band III) standard which was conceived to be purely digital. If a station is maintaining a FM station (200kHz) and is also part of 1.5 MHz multiplex, this does not strike me as very efficient or superior.

From what I understand, DAB+ is operated in Australia at data rates for some broadcasts at 32 kbit/s, for many at 48 kbit/s particularly commercial stations, and the ABC uses 64 kbit/s and 80 kbit/s. You could easily achieve this in DRM if you use the VHF version. I hope you have also taken note of what actually makes DRM super efficient and superior in the FM band (See a new announcement).

In AM/MF your channels are 18 kHz wide with overlapping by 9 kHz. So the bit rate in simulcast will be a maximum 30.9 kbit/s. I suspect you are talking about music stations where the performance of xHE-AAC and HE AAC V2 is the same, so you might have a point here. However, maybe it is worth examining closer DRM for VHF and its potential which is quite something and certainly not inferior to any other standard.

Perhaps I should also mention the ability of DRM, like DAB+, to use single frequency networks SFN, so many frequencies could be made vacant by the ABC using a single frequency networks for Radio National which is mainly AM and some ABC newsradio channels.

radioinfo said:
However, DRM would not be successful if there were no receivers.
Ruxandra concurred:
Agreed. And works is going on this project, as we speak.
radioinfo said:
If DRM was ever to be seriously considered for Australia it should be considered as a supplementary service and all new receivers should be mandated to include DAB+ and DRM reception, as well as FM and optional other analog formats, otherwise it would not achieve the coverage it would need to have to benefit consumers.
Ruxandra took issue with the terminology:
To brand it “supplementary” is maybe the wrong word. “Complementary” is how it should be characterised. DRM offers full country coverage, filling in all the gaps and bringing with it all the advantages of digital, including multi-media services, not fully exploited or presented on DAB, I think.

Ruxandra’s final comment was:

DRM would enhance DAB+ and offer genuine nationwide coverage and equal access to information and entertainment to all Australian taxpayers.  The heartfelt submission by the First Nations Media, for example, where they appeal for equal access for all groups, can be achieved only with DRM as a complimentary digital solution. An ACMA or government recommendation would unlock deployment and availability of DAB+/DRM receivers that would surpass what is currently available.

As usual, your views and comments are welcome in the comments section below or to [email protected].

See related article: 21 submissions received for ACMA’s Future of Radio consultation: Analysis




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