In many countries, notably China (see separate item), the 3.5 GHz band is being identified as an important one for 5G. Traditionally allocated for fixed wireless, it is being opened up by regulators for mobile 4G and 5G, and possibly for shared access using emerging technologies like MulteFire. Last week, SK Telecom announced South Korea’s first trial of 5G systems in the band. Although many of the new developments in 3.5 GHz have been spearheaded in the US – where the FCC has introduced an innovative, if complicated, three-tier system of access – that early movement risks leaving the US out of the band plan mainstream again, if the rest of the world adopts a different approach and moves quickly…