“Our latest research shows that the data density can be 2,000 times higher than using radio links,” Professor Haas claims.
The idea capitalises on a growing trend in wireless communications – the convergence between mobile telephony and wi-fi internet access, once built for good reason to very different specifications. In fact, says Apurva Mody, who chairs an international committee developing standards for wide-area wireless internet access, mobile operators have saved themselves $50-99 billion a year by offloading a lot of data-intensive traffic to smartphones via the internet. That’s because every time you download a video to your smartphone through your home (or work) wi-fi, you've eased the load on the phone system.
“If all that data had come through the mobile networks,” he argues, “they would have had to build another 350,000 towers to meet demand”.
This kind of thing helps, of course. But part of the appeal of mobile – and one of the reasons it grew so quickly – was that it unshackled people from fixed connections. To continue its growth, mobile firms know that any solution to the bandwidth crunch needs to provide the same freedom. Hence why the industry is constantly scrutinising the radio spectrum for any new opportunities.
Currently, everything up to 300 GHz is spoken for - mobile phones are only permitted to use tiny portions, squeezed in between the bands allocated to broadcasters, radar, air traffic control, the military, satellite communications, even astronomers for whom keyholes must be left clear so they can tune into the universe. That's why every time a little more spectrum is released from some defunct use, operators are prepared to spend billions for a small slice of the new radio resource.
As a result, mobile firms are also looking at ways to use their existing capacity more efficiently.
And it is here that they may strike gold, according to Professor Lajos Hanzo, head of the department of telecommunications at the University of Southampton.
“The coding techniques used in smartphones are inching towards their theoretical limits,” he says. “But those are under idealized conditions. In the real world, their implementation rarely reaches the theoretical performance. “
In other words, if you're standing right next to a radio mast, with no other users in sight, and there's no radio interference, your link will be just about as strong as it theoretically could be; there would be no way of squeezing more bits through the spectrum.
But the world is not like that. We are far more likely to find ourselves far from the base station, wirelessly shouting to be heard among all the other transmissions, our signal broken up by reflections off metal buildings, or fractured by leafy trees. And it is these calls - straining from near the cell edge - that account for most of the shortfall from theoretical performance.
Various tricks are being considered to compensate for these deficiencies.
For example, Phil Pietraski and Bob DiFazio of Interdigital Communications, have proposed the idea of fuzzy cells. Cell edges, they reason, do not have to be rigidly defined. When we're at the edge of one cell, we are also within earshot of the next. It's a matter of convenience that our mobiles talk to one mast and not the other until we cross some imaginary line on the ground.
Fuzzy cells blur the boundary. Pietraski and DiFazio say it is possible to tweak the radio transmissions from towers in such a way that their footprints overlap at the edge, so that users approaching the mobile no-mans-land become connected to two masts, while other users further from the crossover don't suffer from additional interference.