Control plane signaling flows
LTE eNodeB S1 startup, MIB-SIB broadcast and RRC connection
Learn about eNodeB startup: (1) eNodeB performs an S1 setup (2) MIB and SIB broadcast (3) eNodeB sends UE specific configuration information via the RRC Connection Setup message.
LTE Random Access Procedure and Contention Resolution
This sequence diagram explains with an example how LTE UEs connect to the eNodeB. Contention resolution between UEs also explored in this flow.
S1AP View of LTE Attach and EPS Bearer Setup for Two PDNs
Explore the S1AP handling of: (1) LTE Attach (2) PDN Setup and Default Bearer Setup for two PDNs (3) UE context release (4) Service Request.
Tracking Area Update Signaling Flow
The flow describes a tracking area update that results in MME change.
LTE X2 Handover Sequence Diagrams
X2 interface connects eNodeBs in LTE. Explore the inter eNodeB handover procedures over the X2 interface.
LTE S1AP View of an Inter-MME S1 Handover
Examine the S1AP messages involved in an S1 Handover at full message level detail. In this scenario, the source and target eNodeBs are served by different MMEs.
Inter-working with 3G and 5G
LTE to 3G Circuit Switched Fallback (CSFB) Call Flow
A 4G LTE subscriber initiates a voice call in an LTE network that does not support VoLTE. In such cases, the UE falls back to 3G networks to establish a voice call.
Presentations and Tutorials
LTE Tutorial Presentation
LTE presentation with audio narration. OFDM basics, LTE channels, signaling procedures and MIMO are covered.
LTE Radio Link Control (RLC) Presentation
Covers Transparent Mode (TMD), Unacknowledged Mode (UMD) and Acknowledged Mode (AMD). RLC state variables and PDU formats are also described.
LTE RRC Connection Setup Messaging Presentation
Describes the RRC connection signaling procedure with detailed description of the RRC message contents.
Attach and Default Bearer Setup Messaging Presentation
Messages involved in LTE attach and default bearer setup are described in detail.