Keeping on top of interference

Australian Communications and Media Authority

By Chris Fosten, Manager, Communications Infrastructure, ACMA
Thursday, 19 October, 2017

Keeping on top of interference

Interference diagnosis and management is all in a day’s work for the ACMA and its expert inspectors.

The ACMA plays an important role in managing Australia’s radiofrequency spectrum. For the general public, this means making sure radiocommunications and broadcasting services work without being affected by interference — we all want to use our smartphones and enjoy TV and radio services uninterrupted. For industry and government, it can mean the difference between providing a reliable mission-critical communications service or one that is compromised by unauthorised and harmful transmissions or interference.

Managing interference can be done from behind a desk in some cases, but more often diagnosis and resolution takes ACMA officers into the field and to all parts of Australia — from our major cities to coastal and outback communities. ACMA field staff, who are technically qualified and appointed as inspectors, respond to complaints of interference and work hard to make sure everyone gets the most out of Australia’s radiofrequency spectrum.

A typical day in the field

A mobile phone carrier reported to the ACMA that one of its base stations near Flemington, close to Melbourne’s CBD, was experiencing interference. An ACMA officer travelled to the area to find the source and stop the interference.

The information pointed to a transmitter located in a housing area close to the Flemington Racecourse. The ACMA officer scoured the area using a spectrum analyser to gauge the signal strength and find the location of the transmitter. The high-density housing complicated the search because it caused high signal reflections, but the officer used his expertise to quickly narrow the search down to a couple of houses.

He then used his 800–900 MHz directional Yagi antenna to pinpoint the exact location of the device on the second floor of a townhouse, near an external wall. With the cooperation of the resident, the inspector quickly identified a malfunctioning indoor TV antenna booster as the source of the interference. This type of device should not transmit radio signals in the mobile phone band.

The inspector explained to the resident why the device couldn’t be used and advised on how TV reception in the townhouse could be improved. The device was disconnected and an advice notice issued to reinforce the information he had provided.

With the booster out of action, the carrier’s mobile network was restored to its normal performance.

While ACMA inspectors are travelling around, they normally have a spectrum analyser running in the vehicle. This picks up any unusual radiocommunications activity. In the Melbourne suburb of East Brunswick, the analyser identified interference in the 1920–1930 MHz frequency range — the frequency used for mobile phone services in Australia.

Stopping his vehicle, the inspector used his 1900–2100 MHz directional Yagi antenna and spectrum analyser to determine the direction of the signal. He soon narrowed it down to a nearby commercial multistorey building and tracked the signal to a first-floor business.

After introducing himself and explaining the reason for his visit, the inspector searched for the source of the interference. Again, the antenna and spectrum analyser came into play, zeroing in on the interfering signal and identifying the device as a wireless VoIP server. The server was part of the business’s telecommunications set-up and, while other pieces of their phone equipment were appropriately labelled with the relevant compliance mark, this device was not.

The wireless VoIP server wasn’t licensed to operate under the carrier’s spectrum licence or the Cordless Communications Class License, which would generally authorise devices of this kind. In this case, this licence did not apply because it was operating on frequencies outside of the allocated band.

The device was disconnected and the inspector clearly explained why the device could not be used in Australia. He also issued a warning notice for the unlicensed operation of a radiocommunications device.

View of the screen of a handheld spectrum analyser

Spectrum analysers enable ACMA field officers to detect interfering signals.

The lowdown on spectrum reform

Australia’s spectrum is managed using a framework that was developed in 1992. In 2014, the Department of Communications and the Arts (DoCA) instigated a Spectrum Review to look at whether changes are needed to cope with the increase in demand for spectrum and changes in technology, markets and consumer preferences. The review report was released by the Minister for Communications in May 2015.

In August 2015, the government announced that it had accepted all the recommendations of the Spectrum Review and would replace the current legislative arrangements with new legislation that removes prescriptive processes and streamlines licensing.

The exposure draft of the Radiocommunications Bill 2017 released by DoCA in May 2017 aims to simplify the legislative arrangements relating to resolving interference disputes. The Bill provides for:

  • a discretionary power for the ACMA to make interference management guidelines (the guidelines) regarding procedures for resolving interference complaints;
  • a discretionary power for the ACMA to investigate interference complaints and for it to inform the complainant of the results of the investigation;
  • the provision by the ACMA of an alternative dispute resolution service directed towards resolving the interference complaint. The ACMA may also refer interference complainants to one or more providers of dispute resolution services.

Part 5 of the Bill also provides for a right of action available to licensees in the Federal Court.

Looking ahead

While new legislation is still being developed, the government has clearly set out its policy objectives. In other countries, some of the interference management services that the ACMA provides are supplied by the private sector — for example, a German company that operates around the world and provides ‘interference hunting’ services in several countries including the US. Faster response times and overall cost-effectiveness are cited as drivers for mobile carriers using its services in the US rather than seeking recourse to the regulator.

The ACMA expects that demand for interference diagnosis services is likely to continue to grow. Under current arrangements, it is possible that demand for interference diagnosis services could become greater than the ACMA’s ability to supply those services to an acceptable quality or in an acceptable time frame. Demand for ACMA interference diagnosis services could be managed by further rationing services through established case prioritisation processes, charging for interference diagnosis services or a combination of the two.

Consistent with the Radiocommunications Act 1992, the ACMA is proposing to clarify and refine its interference diagnosis role within the interference management framework in accordance with Recommendation 1(e) of the Spectrum Review — allowing licensees to resolve interference and disputes — including:

  • encouraging licensees to access alternative dispute resolution;
  • requiring the ACMA to develop and publish guidelines on its dispute management processes;
  • expanding rights of licensees to undertake civil proceedings.

If adopted, this type of approach would see a transition from the ACMA being the major provider of interference diagnosis services to an interference management framework that increasingly enables and facilitates the provision of interference diagnosis services by third parties. There would be additional incentives for parties to an interference event to independently resolve the issue when the level of harm and seriousness did not warrant regulatory intervention.

Getting involved

It’s important that regulatory decisions are informed by evidence and take into account the views of those with an interest in the outcome — our stakeholders. For instance, this year’s RadComms event included an interference management workshop, which enabled participants to be involved in the development of new arrangements. The ACMA welcomes feedback and input on radiofrequency spectrum interference and other matters via its ‘Interference investigation service’ web page at

Images courtesy ACMA.

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