Back when I worked with LTE (now 4G) there was no such thing in the S1AP protocol at least. Me, and a colleague, where actually the first to get a paging throu

Back when I worked with LTE (now 4G) there was no such thing in the S1AP protocol at least. Me, and a colleague, where actually the first to get a paging through from network to a UE in LTE. Sure, it was a test UE the size of a small refrigerator, and the network was a simulated network. But still. All layers involved. The paging, at the time, was the only way for the network to silently contact the UE, and that message didn’t contain any information. It was basically just a: “Hello IMEI X, are you here?”