Stargazing with spectrum in mind

While spectrum, its accessibility, allocation and use were the all-absorbing topics of the ACMA’s fourth RadComms conference, the authority’s chairman, Chris Chapman, covered a range of other topics in his opening address in Melbourne. This is an edited version of his presentation.

He stressed that to cooperate and standardise are essential, otherwise there may be no spectrum available to implement some of the smart infrastructures of the future. He cited, as an example, intelligent transport systems where roads can be fitted with sensors and vehicles using the road can also have sensors that will detect and report air pockets before cracks and potholes appear in the road surface.

Bridges, too, could be fitted with sensors to show cracking and fatigue and all this information can be relayed by radio so that remedial action can be taken. He suggested that this line of thinking could be further extended to monitoring the heights of rivers and the condition of land or livestock, with all this information transmitted to passing vehicles, suitably fitted with receivers, for later download.

“So the simple concept of ITS opens up a Pandora’s Box of possibilities limited only by the imagination of our engineers and scientists,” he said. But the bottom line is going to be available spectrum for such innovations.

Ultrawide band is a recent development in radio acoustic detectors that can reveal people or things moving inside buildings, underground or through walls. Although in its early stages, it could be used to find hostages, people trapped in collapsed buildings or those buried underground.

UWB can also connect a television monitor with a set top box or PVR, it can be used by vehicles to detect threats ahead, and by the military to transmit data at such low power it is virtually undetectable.

“Of course, as seems inevitable, the bands proposed for UWB are already used by many other applications and the ACMA engineers have worked hard to ensure the power levels at which UWB will operate do not harm these existing applications and services.

“That is their job and I think they do it well. This is a terrific working example of how we are working to deliver sensible, flexible use of spectrum to deliver the public interest, the benefits of technology for as many uses as possible,” he said.

Turning to motes, he described them as very small sensors linked together by radio to form an ad hoc flexible mesh network that transfers collected data to a central point. Engineers are already planning to mix motes with concrete before it is used in construction.

Powered by a combination of vibration and long-life lithium ion batteries, these little devices will be able to report on the health of the structure, transmitting to each other over a very small distance and eventually to a larger transmitter that will send the information to a collection point.

Unmanned aerial vehicles (UAVs) have moved on from science fiction and the Predator, he said. Their potential uses could include hurricane hunting, surveying pipelines, checking power transmission lines, spraying noxious weeds and finding lost bushwalkers.

However, these devices need spectrum too, for control and telemetry, and they also need large quantities of it to download their payload that is usually video or broadband data.

“Again the ACMA is grappling with the problem of finding this spectrum right now,” he said.

He said there is the possible development of a crowd-control weapon that consists of a microwave pain-inflicting system that can be fired from an aircraft. Microwave radio heats the surface of the skin, causing pain but without burning it. At the heart of the weapon is a compact airborne antenna, steered electronically and capable of generating multiple beams, each of which can be aimed at individual targets while on the move.

He talked about experimental treatment that might one day cure paralysis in humans. Some researchers believe that an electronic bypass to reconnect a broken spinal cord is possible. The idea is to plant chips in the brain to record neural activity.

A decoder then deciphers the activity to work out what the brain wants the body to do. The messages are relayed by radio to electrodes that deliver a pulse of electricity to stimulate the muscles into action.

Similar chips are already restoring hearing to the deaf and vision to the blind, so maybe the idea is not that far-fetched, he suggested, and a band of spectrum for these applications would need protection from interference.

But it was not all crystal ball gazing. He said progress is being made, with the release of some spectrum in the 3.6 GHz band, the release of the final paper on the 2.5 GHz band and the Green Paper on the 700 MHz digital dividend. And it may be that another 300 MHz will become available for mobile broadband.

Finally, he said: “It is an essential part of the ACMA’s job to look over these horizons to seek, to grasp what is coming, perhaps sometimes to guess. This way we can facilitate the connection and transition between the spectrum solutions and applications that operate today and the exciting opportunity-laden, yet confronting, totally interconnected mobile world that is tomorrow.”