In many ways, LTE was a bigger architectural and cultural leap for mobile operators than 5G will be. They had to move to a flat all-IP platform, for which HSPA had only partially laid the groundwork. The System Architecture Evolution (SAE) which accompanied the LTE radio standards defined a flat IP network around an evolved packet core (EPC). In theory at least, 5G should be just an extension of that fundamental shift away from circuit-switched, hierarchical networks of 2G and 3G. However, to fulfil its lofty objectives, 5G will need to be more than an enhancement to current 4G – otherwise, standards organizations and vendors could continue to squeeze more out of LTE for many years to come, with none…