IEE Telecommunications Consultant Contents Introduction 26/3 Frequency assignment 26/3 26.3 International frequency allocation 26/6 26.4 International spectrum management 26/7 National frequency management 26/14 26.6 Efficient spectrum utilisation 26/15 26.7 References 26/18 This page intentionally left blank Introduction 26/3 26.1 Introduction 26.2 Frequency assignment Governments manage the use of the radio spectrum to prevent the 26.2.1 National frequency assignment degradation by interference of a valuable resource, to ensure that radio systems use spectrum economically, leaving room for new Each administration maintains a register of the frequency assign- users and new uses, and to provide for the orderly use of frequencies ments that it has made, recording where each assigned frequency is where this is necessary for practical reasons. transmitted and received and the more important parameters of To ensure that these objectives can be attained, governments insist emissions. The use that is made of the spectrum is monitored, to that there should be no transmission of radio signals without per- ensure that unauthorised transmitting is stopped and that transmit- mission, signified by a licence. Licences are also required for many ting licences that are not put to use are withdrawn. receiving stations. Exceptionally, a general authorisation may be When a new assignment is to be made and the emission par- given for specified frequency bands to be used for specific kinds of ameters required for satisfactory operation, such as the transmitter very low power device without formality, it being assumed that the power and the bandwidth to be occupied, have been determined, a possibility of interference can be disregarded in such cases. search can be made through the register to identify frequencies in Most licences specify the carrier frequency which has been as- appropriately allocated bands that may be suitable for assignment. signed for use at a named station, together with other technical The information in the reg