Over the last decade business radio (PMR) has become a victim of its own success, caught between the ever increasing demands of its users and the limitations of a finite radio spectrum.
The fixed channel allocation makes for simple operation, but is inefficient in the use of radio spectrum. Under the fixed allocation system, a user who finds the designated channel occupied is obliged to wait until it becomes free, even if other channels allocated to other operators are not in use. A common pool of channels, allocated to users when required would clearly promote more efficient use of the radio spectrum. The efficient management of a pool of communication channels is a complex computational task. Developments in microprocessor technology, signaling protocols, digital switches and frequency agile transceivers have enabled Trunked systems to become economically viable.
Trunked systems make more efficient use of the radio spectrum, contribute to more efficient channel utilization, simplify frequency planning/allocation and reduce interference, provide a template for an easily maintained resource management system, provide a wide range of user facilities (including PABX/PSTN connection, data transmission, and call queueing), improve the grade of service, provide sharing users with all the basic characteristics of a private system, extend operational coverage, facilitate the provision of wide area nation-wide systems as well as smaller local schemes.
Trunked systems benefit everyone concerned - the regulatory authorities, network operators and end-users.
