Mention radio waves and most people think of wireless radio signals. But radio frequency - also called "spectrum" - refers to the different wavelengths of electromagnetic radiation - radiation or waves that are produced from the motion of electronically charged particles, and include visible light, x-rays and microwaves.

Parts of this spectrum can be used for broadcasting a signal by an antenna, and those signals can then be picked up by a plethora of devices and for a wide range of communications uses.

The devices operate in specific bands of spectrum, which is allocated for such use by national bodies such as ComReg in Ireland. Some spectrum is used for radio and television broadcasts.

But what many people don't realise is spectrum is also allocated to mobile phone operators and wireless internet providers and satellites, and spectrum is dedicated to industrial, scientific and medical (ISM) use. If you use a Bluetooth headset, a wireless home network, a garage door opener, a cordless phone or like to fly model aeroplanes, you are using ISM spectrum. With the explosion in electronic devices, computing and telecommunications, spectrum is becoming scarce.

The spectrum pie can only be sliced so many ways, and in many countries, the slices are nearly gone. But this doesn't mean the full slice is being used -- indeed, in most cases, spectrum is not used efficiently. For example, with telecommunications operators, a large part of the spectrum allocation licensed to them may lie idle or be only fractionally used, while congestion occurs in other spectrum frequencies. If devices or operators could hop between bands of spectrum, this would enable many more uses for these frequencies and many new applications and services.

But spectrum is so scarce that researchers have not yet been able to experiment with how this might work -- because regulators have not been willing to turn over a band of spectrum for such use.

The Centre for Telecommunications Value-Chain Research's "plastic playground" project, which includes researchers from several rish organisations such as BellLabs and TCD, has been granted the first-ever chunk of spectrum for such use by ComReg.