Each new iteration of mobile telecommunications technology that offers substantial improvements over the last is referred to in terms of its “generation,” so 3G is simply the third generation of telecoms technology, and so on. 2G introduced data transfer and SMS messaging, while successive iterations have mainly focused on improving data and mobile internet services.
5G, the latest generation, is expected to greatly improve both the speed and latency of mobile data, which will in turn aid automation, the IoT, and AR and VR.