Radio waves do not respect national borders and many uses of the radio frequency spectrum have an impact outside the territory of the country in which the operation occurs. Sometimes this is deliberate as, for example, in short wave broadcasting or international satellite communications or sometimes it is simply unavoidable. International harmonization of spectrum utilization is also important for many applications because users of communications services are not stationary (roaming) e.g. maritime, aeronautical, mobile telephony, etc. International harmonization can also reduce equipment costs through economies of scale and can reduce the possibility of harmful interference.
The governance of spectrum use on a global basis is a core responsibility of the International Telecommunication Union (ITU) and, in particular, its Radiocommunication Sector (ITU-R). The ITU is a specialized agency of the United Nations with its headquarters located in Geneva, Switzerland. It is important to recognize that the ITU is not a global regulatory authority in the way that a national regulator is within its own jurisdiction since the rules for international regulation and cooperation are written by those governed by them, i.e., by the Member States of the ITU. These rules are administered by the ITU-R’s Radiocommunication Bureau (BR) in Geneva and conformity with the rules is based on goodwill rather than on the kind of regulatory sanctions found at the national level. The mission of the ITU-R sector is, inter alia, to ensure rational, equitable, efficient and economical use of the radio frequency spectrum by all radiocommunication services, including those using satellite orbits and to carry out studies and adopt recommendations on radiocommunication matters.
The ITU's Telecommunication Development Sector (ITU-D) has well-established programmes of activities. These programmes to facilitate telecommunication connectivity and access, foster policy development, assist in regulatory and network readiness, to expand human capacity through training programmes, to formulate financing strategies, and to e-enable enterprises in developing countries. These programmes are designed to address topics of interest to spectrum regulators.
In addition to activities carried out within the ITU framework, there are often, of course, bilateral and multi-lateral agreements by which the use of spectrum is harmonized across national borders. There are two general categories of international activities, namely project activities and transactional activities.