Guest editorial

Although the capability for mobile radio communication has been available for some time, the last few years have seen an increase in interest in this subject, particularly with respect to system design and development. One reason for this renewal of interest has been US FCC Docket 18 262, promising to reallocate the upper end of the UHF television band (channels 70-83) for mobile radio communication. In 1968, the FCC opened Docket 18 262, proposing to double the spectrum for private systems by the allocation of an additional 40 MHz, and to bring the common-carrier service into parity by the allocation of 75 MHz. Although the outcome is still pending, this possibility of serving what is recognized to be a large pent-up demand has stimulated research and development. While there have been significant advances in the state-of-art over the last thirty years, particularly in the area of equipment technology, until recently, the lack of spectrum has discouraged innovation in system architecture. There are not very many operational variations possible for a system with one channel, or at most a dozen. But the flexibility inherent in a contiguous block of 800 channels provides the capability for sophisticated systems with vastly increased spectrum efficiency. And, as described in papers in this issue, such system designs have been forthcoming.