vices. These functions have become more critical as subscribers worldwide depend on their mobile devices when they travel for business and leisure. In the United States, the International Bureau of the FCC, the National Telecom- munications and Information Association (NTIA), part of the Commerce Depart- ment, and the State Department are working with the ITU. Generally, working groups comprising representatives from many countries hash out particular issues under the auspices of the ITU. Decisions are made at the ITU's World Radiocommunication Conferences (WRC), held every five years. The FCC and the NTIA jointly manage spectrum allocation in the United States. Finite Spectrum for Wireless Networks Geographic Licensing Schemes In Europe as well as in many other locations, when governments offer spectrum to carriers, they offer it in country-wide swaths. However, in the United States, spectrum auctions for mobile service initially only covered portions of the geographic region. Part of the reasoning is that this encourages competition. In addition, it was felt that the United States is SO large that purchasing nationwide coverage could be cost-prohibitive for entrepreneurs. As a result, no carrier's network provides complete geographic COV- erage across the entire United States. This is starting to change. In the 2008 700MHz auctions, carriers were allowed to bid on large swaths of spectrum in Regional Economic Area Groupings (REAGs) that encompass more territory than the business economic area, metropolitan, and rural groupings. There are six regional groupings in the contiguous United States and others for regional groupings such as Alaska and Hawaii. The Gulf of Mexico also retains its own grouping. Verizon Wireless and AT&T Mobility cover almost all of the metropolitan areas in the United States, but not all of the rural areas. No other carrier has such extensive coverage or the financial wherewithal to purchase spectrum to cover these large areas. Mitigating Interference When transmissions use the same frequ