If you think it isn’t long since your smartphone started using 4G, you're right. Telstra, Optus and Vodafone switched on their networks between 2011 and 2013. Adoption was rapid. By the end of 2014, 40 per cent of Australia’s mobile customers were using 4G, although Optus has only recently shut down its 2G network and Vodafone’s is scheduled to close in a few weeks. So what is 5G, why might we need it, and why is it suddenly dominating the telecommunications policy agenda in Australia? Communications minister Mitch Fifield told a conference in Sydney in late July that 5G would be “a truly revolutionary event, an inflection point not just for the telecommunications sector but for the whole Australian economy." Chris Althaus, long-time CEO of the Australian Mobile Telecommunications Association, which represents Telstra, Optus and Vodafone, talked of a "Fourth Industrial Revolution" and “a fundamental change in the nature of the mobile experience."