Paired and Unpaired Spectrum
Expansion of consumer demand for cellular communications, as well as for the multitude of other wireless systems and applications, places a corresponding strain on the basic physical resource needed to support them: spectrum. The suitability of spectral resources to a particular application is governed by a range of inter-related factors of a technological, commercial or regulatory nature. Technological considerations influencing the choice of frequency band include propagation characteristics, antenna size and separation, the viability of Radio Frequency (RF) circuitry, and design implications resulting from the need to coexist with systems operating in neighbouring spectrum without causing (or suffering from) undue interference. These considerations determine in part the commercial viability of a system. Signal range and spectral efficiency govern coverage and capacity, and hence determine the required number of base station sites and the capital outlay, whilst terminal costs and form factor affect the acceptability of products in the marketplace.
From a regulatory perspective, in spite of significant coordination at an international level through the International Telecommunications Union (ITU), regional variations in governmental policy regarding spectrum and technology are inescapable due to the differing needs of each region and the different historical factors which have shaped their present-day ...