LTE Reference

LTE Protocols

The LTE protocol stack defines how data and signaling are transmitted across the radio interface and core network in 4G systems.

This page provides a structured reference for key LTE protocols, including PHY, MAC, RLC, PDCP, RRC, and NAS, with explanations aligned to 3GPP specifications and real network behavior.

The content is organized layer by layer, helping you understand how physical transmission, data transport, and signaling procedures operate together in LTE networks.

NAS RRC

Released Protocols

Layer: Core signaling Open

NAS

EMM and ESM procedures, states, causes, and session control references.

Layer: Access stratum Open

RRC

Radio resource control procedures, states, system information, and timers.

Recently Added Protocol Pages

LTE RRC Timers: T300, T304, T310, T311, T320 Reference

LTE RRC timers reference based on 3GPP TS 36.331 Release 18. Check T300, T301, T302, T304, T305, T310, T311, and T320 for connection setup, re-establishment, handover, radio link failure, and redirected-priority behavior.

LTE NAS ESM Cause Values: Missing or Unknown APN, Unknown PDN Type, User Authentication Failed

LTE NAS ESM cause values reference based on 3GPP TS 24.301. Check missing or unknown APN, unknown PDN type, user authentication failed, insufficient resources, regular deactivation, QoS and TFT errors, PDN disconnect and bearer-management failures.