Overview
Summary
These LTE notes are designed for anyone who wants to learn 4G LTE.
The focus is on easy understanding first, while also providing deeper paths and reference links if you want to explore specific topics further.
So, enjoy the LTE journey!
Tip
Each page starts with the big picture, then moves into protocol-level or more intuitive explanations to help you build understanding.
After that, it may go deeper into specific areas such as protocols and physical layer details.
LTE System Architecture¶
Figure 1. Open5GS 4G/5G NSA and 5G SA System Architecture, showing Control/User Plane Separation (CUPS)1
LTE Attach Call Flow¶
Figure 2. The LTE attach call flow
Useful Resources¶
- ShareTechnote — Main Components of E-UTRAN and EPC
- EventHelix — LTE Tutorials and Call Flows
- 3GPP TS 23.401 — GPRS enhancements for E-UTRAN access: the authoritative source for the full attach flow
-
Lee, S. (n.d.). Quickstart [Architecture diagram]. Open5GS. https://open5gs.org/open5gs/docs/guide/01-quickstart/ ↩