Originally Posted by
gfunkdave
I think this, too, is wrong. My recollection is that AT&T won the bid process for the 2100 MHz spectrum. They paid more for it, pure and simple.
The problem isn't the 2100 MHz spectrum at all. It's the 1900 MHz.
The original UMTS standard was 1885–2025 MHz uplink and 2110–2200 MHz downlink. This is known as "2100 MHz" or sometimes "1900/2100 MHz". It's what most of the world uses.
However the 1900 MHz band was already being used for 2G services in the US. Hence AT&T could replace some of its 2G spectrum for 3G, using 1850-1910 MHz for uplink and 1930-1990 MHz for downlink. This is why AT&T's 3G is incompatible with most of the rest of the world.
T-Mobile, without access to the 1900 MHz band, could still use 2110-2155 MHz for downlink but was forced to use 1710-1755 MHz for uplink. Hence the incompatibility with
everyone.