LTE-M architecture — Cat-M1 and Cat-M2

LTE-M as a Narrowband UE Class

LTE-M is best understood not as a separate technology but as a set of UE categories within LTE — Cat-M1 (Rel-13), Cat-M2 (Rel-14), and reduced-capability variants in later releases. The eNodeB itself is an ordinary LTE base station with appropriate software. What changes is the device: an LTE-M UE has a maximum bandwidth of 1.4 megahertz (Cat-M1) or 5 megahertz (Cat-M2), simpler RF, and lower processing capability. The device still benefits from LTE features it can use — handover, voice over LTE, full mobility — but is designed and priced for IoT use cases that do not need full smartphone…