A geographic area of integration of population and economy ( several adjacent segments ) that is Rand Mc Nally commercial Attas is defined . BTAs FCC , as the geographical boundaries for the licenses ( spectrum ), radio frequency ( 1900MHz ) PCs to be used in the mid 1990 to auctions laid . Some parts of the band, pcs as MTAs ( regions (central business district ) to the auction were laid out, each of which consists of several BTAs . Other bands, such as bands, cellular ( 850 / 800 MHz) instead of the divisions, geographical, MSA and RSA .