Wireless won't deliver the bandwidth we need, says Quigley.

Stuart Corner
Thursday, 10 December 2009 08:06

Business IT - Technology

It's been said many times by many eminently qualified experts yet NBN Co executive chairman Mike Quigley felt it necessary to once again counter those who claim that wireless will deliver the bandwidths we need.


He told the Government's "Realising our broadband future" forum in Sydney today that: "While wireless is currently enjoying high growth rates, it has inherent limitations compared to fibre. It is simply very difficult to overcome the limits imposed by physics.

"Spectrum is a scarce resource and there is just so much you can do to increase spectral efficiency using better modulation or coding schemes. We have seen real increases in speeds and download capacities offered with wireless networks in the last decade. Some of this is due to more spectrum becoming available, to larger channel bandwidths and to better modulation techniques."

Those who support wireless frequently cite these facts. However Quigley said: "By far the most important factor in the growth of total wireless capacity has been the increasing number of cells and the shrinking of cell sizes. This factor outweighs, by several orders of magnitude, all the other factors that have led to the million-fold increase in wireless capacity since the 1950s."

And, as he pointed out, the further this is taken the closer the network comes to being a FTTP network. "We can, [just keep increasing the number of cell sites and continue to reduce cell sizes] but we still have to haul the traffic out of the cell sites and for that we need fibre. As traffic demand increases we can keep reducing the size of these fibre-connected cells so we end up with a very large number of cells each serving a small number of premises."

Quigley said he doubted that this would be a cheaper option that FTTP adding: "We must remember that wireless is a shared medium, and so we must factor contention into the access traffic calculations. Peak speeds may be high and equal to those of fibre currently, but average speeds are dramatically lower. High bandwidth, constant bit rate applications such as IPTV and [high definition videoconferencing] are very challenging over a wireless network. It is also the case that users at the edge of the cell experience a far lower grade of service than those in the centre."