r summary of the available options and their comparative merits can be presented as shown in Table 2.1. Self-evidently guided media cannot provide mobility in any meaningful sense of the word unless walking in a circle with a cable in your hand happens to be acceptable. What is immediately apparent is that all these delivery options represent work in progress and are all moving forward in terms of supported data rates and user functionality. 2.2 The Transfer of Bandwidth from Broadcasting to Mobile Broadband Fifteen years ago this prompted Professor Nicholas Negroponte to suggest that as the capacity of guided media increased over time it would become steadily less sensible to use wireless broadcast as a way of communicating with static users - the 'Negroponte switch'. This and similar thinking encouraged the regulatory community to transfer bandwidth from terrestrial broadcasting to mobile broadband. Fortuitously for national treasuries this created lucrative spectral auction opportunities that in some, but certainly not all, cases also yielded longer- term shareholder value for the bidding entities. However, even taking this redistribution into Making Telecoms Work: From Technical Innovation to Commercial Success, First Edition. Geoff Varrall. © 2012 John Wiley & Sons, Ltd. Published 2012 by John Wiley & Sons, Ltd. Table 2.1 Guided and unguided media Unguided media Guided media Fixed wireless one Fibre optic Coaxial cable Twisted pair Free space optics way/two way Portable wireless Mobile wireless 50-year-old upstart 50-year-old upstart 150-year-old grand 30-year-old 100 years of 100 years of 100 years of history, Highest bandwidth, Can convey a larger old man of upstart, high history, still a history, still a still a long way to lowest attenuation volume of data telecommunica- data rates except long way long way to go and lowest than copper of tions can now in dense fog to go Has to adapt to very specified bit error the order of 200 support 1 Mbps variable channel rate of all delivery Mbps but does over short 