April 28, 2008 12:44 PM BST
Haven't seen anything published to the general public other than the standard sales and marketing mumbo jumbo. The different system vendors do internal studies short and long term, of course, but this is unfortunately not transformed into white-papers.
The answer is found in the success of data traffic with each operator. In the Nordic countries we are at 34 Mbit/s in the big cities. Not all sites, but a significant number of them require this, and there is an anticipation that this will ,very shortly, not be enough.