From Leon di Marco, leon.dimarco@btinternet.com
Paul Marks is correct that WiMAX data rate performance has been misrepresented (29 October, p 26). Some of the media have used 70 megabits per second and 50-kilometre range in the same sentence, which is a physical impossibility. It does not take “calculations” to work out the actual user data rate, since the 70 megabits per second raw rate is shared by many fixed end-users on the last mile connection – giving a rate about of about 1.5 megabits per second per user, as the article states.
To say that fixed WiMAX offers nothing that third-generation (3G) cellphones will not soon be able to achieve is wide of the mark, as fixed WiMAX was intended as a last-mile service for places that don’t have mobile coverage; it will take a very good service using 3G to offer 1 megabit per second in any case.
The article is correct to be sceptical about mobile WiMAX. This will be a technical tour de force if it works at all, and will involve quite extraordinary amounts of signal processing at both the user’s end and the base station.
