Special Report: Spectrum diversifies The cellular industry, predictably enough, is already starting to discuss 6G, particularly in relation to radios that could use very high frequency spectrum in the sub-terahertz bands above 100 GHz. As an engineering challenge and bluesky research activity, this is fascinating, but many operators are heaving sighs of frustration that we are talking about 6G when very few of them have used much of their millimeter wave 5G spectrum, or even their midband frequencies, to date. However, they do all agree that commercial 5G success will rely in part on a diversification of the spectrum landscape. Already, the system of long, exclusive and expensive licences, usually allocated on a national basis, is being augmented by local…