Carriers in many countries are facing the dilemma of what to do with their 2G networks – preserve them to support existing low end customers and machine-to-machine (M2M) services, or shut them down in order to reuse the spectrum for 4G? Some operators plan to take the latter path as soon as possible. In Japan and South Korea, the 2G networks are shutting down, and AT&T and Verizon aim to follow their lead. AT&T plans to close its GSM network by the end of this year, while its arch-rival will do the same for CDMA 1X, but at a more stately pace, targeting the end of 2019. This is causing consternation among smaller mobile operators – in the US’s complex…