LTE-M CE Mode A vs CE Mode B: Key Differences

This page compares LTE-M CE Mode A and CE Mode B and describes the difference between them.

Introduction to LTE-M

LTE-M, which stands for Long Term Evolution for Machine-Type Communications, adheres to 3GPP specifications much like standard LTE technology. It’s primarily designed to meet the objectives of cellular IoT devices, focusing on low device cost, enhanced coverage, extended battery life, and greater cell capacity.

LTE-M devices are categorized into Cat-0, Cat-M1, and Cat-M2 based on different 3GPP releases. Specifically, LTE-M Cat-0, Cat-M1, and Cat-M2 are compliant with the 3GPP TS 36 series, relating to releases 12, 13, and 14 respectively.

Let’s examine the messages exchanged between an LTE-M device and a base station (eNB) during the LTE-M RRC Resume Procedure.

LTE-M RRC Resume Procedure

The diagram illustrates the LTE-M RRC Resume procedure. The messages passed between the UE (User Equipment) and eNB are grouped into four phases:

1. Synchronization Phase: Acquisition of PSS (Primary Synchronization Signal), SSS (Secondary Synchronization Signal), and PBCH (Physical Broadcast Channel).
2. Setup Phase: Connection establishment phase.
3. Data Transfer Phase
4. Release Phase