Chris Barton: Sorting the facts from fiction of interference

Interference is at the crux of state-owned networking company BCL's filing of a judicial review against Walker Wireless, radio engineer Robert Vernall and the Ministry for Economic Development.

It is not interference of the political kind - although BCL has been accused of trying to undermine the Government's Probe project to promote broadband competition.

Nor is it interference of the business kind - although BCL has been accused of trying to kneecap rival Walker Wireless.

The interference here is of the electromagnetic kind, and the case, due in the courts this week, throws into question just what interference is. It also raises a deeper concern about the nature of spectrum and how the airwaves, ether, or whatever you call this mysterious realm, should, or could, be regulated.

The nub of BCL's case is that Vernall, who certified Walker Wireless' broadband licences, did not consider whether there would be harmful interference to BCL, which owns an adjacent frequency band.

Vernall will no doubt argue that he did consider the potential problem and was confident it could be resolved. How? By having both parties discuss the nature of the problem and then coming up with a technical solution.

Which is where the definition of interference comes in. We tend to think of interference as radio waves somehow colliding - which is of course wrong.

Just as two people can talk to one another without their speech becoming garbled, radio waves pass through the air unimpeded.

Problems of interference occur only at the receiver. So if BCL has trouble with Walker's emissions, the fault is not in the airwaves but in the equipment. Usually such faults can be fixed through modifications to the gear.

Which is why the Radiocommunications Amendment Act 2000 came into effect: to allow for "increased flexibility to deal with new and changing technologies, and promote a more pragmatic basis for resolution of radio interference".

But it wasn't always like that. Radio receivers of old were not clever devices, distinguishing one transmission from another by picking out the strongest. So if two transmissions were on the same wavelength a receiver would not know which to focus on, hence interference.

To deal with these IQ-challenged receivers Governments developed laws, initially to license broadcasters' use of frequencies, and more recently to assign property rights to chunks of radio frequency spectrum.

BCL and Walker each has a band of frequency that they own like real estate, and which they can guard against interference as if were a trespass or a nuisance.

But herein lies a problem - spectrum isn't really like that. As Yochai Benkler, of the New York University School of Law, puts it: "Generally, we use market-based solutions for resource management, and therefore when posed with such a problem, look for something to which we can affix property rights to be traded in the market.

"But there is no such thing as spectrum. There is no ether out there, no finite physical resource that needs to be allocated. There are simply people communicating with each other, transmitting and receiving messages with equipment that uses electromagnetic waves to encode meaningful communications and send them over varying distances without using a wire."

In other words, spectrum is not a scarce resource, but a legal construct that seeks to contain something that is almost limitless. The airways cannot be used up with radio waves.

Such revolutionary thinking has many people pushing for a better way to regulate. They advocate an "open spectrum" - a public space or "wireless commons" (www.wirelesscommons.org) where anyone can send signals across any frequencies without permission as long as they obey a few rules of the road.

In this wireless nirvana, smart receivers decide which signals to accept and which to ignore.

The concept also makes sense in the light of new radio technologies such as spread spectrum, which uses signals over a broad range of frequencies in short bursts; or meshed wireless networks, which co-operate to route signals among nodes.

The open spectrum approach works through the adoption of protocols, in much the same way as the internet. As internet guru David Reed puts it: "We need a regime that allows radio frequency networks to inter-operate and co-operate in use of spectrum in an open and experimental way, just as the internet did."

The first step in adopting such a view would be to stop auctioning off spectrum to monopoly owners that do not use it efficiently.

The second step would be to introduce a "use it or lose it" clause for existing frequency-owners to stop hoarding and to free up unused frequency. None of this would be appreciated by BCL or Walker.

We are unlikely to get such radical argument in BCL vs Walker Wireless because our law is drafted with property rights in mind. But we should hear plenty about the fiction of interference that BCL contends is fact.

Much will hinge on whether the act allows radio engineers to certify licences assuming technology applied to the equipment will address interference.

Either way, the case highlights a need for the Government to review whether the assignment of property rights is the best way to manage frequencies. Or whether by adopting a wireless commons approach, the sky would indeed be the limit for communications.

* Email Chris Barton