The FCC has finally approved the spectrum transfer that was part of a $4 billion breakup fee that AT&T promised to T-Mobile if the companies failed to merge. Following AT&T's decision to call off the acquisition in December of last year, the two companies applied in Janurary to the FCC to get the green light for the spectrum transfer. The spectrum, which is estimated to be worth $1 billion, is in the AWS band and it covers 128 cellular market areas. Be sure to check this map to see where AT&T is losing some of its spectrum. While T-Mobile currently relies upon its AWS spectrum for its 3G network, it plans to use the additional capacity gained by the breakup fee to help it play catch-up and launch its own LTE network in 2013.