40415 «LTE Protocols and Procedures»

Course Code




This 3 day course covers the LTE RAN protocols and procedures. After a review of the EPS system architecture the course focus on protocols and signaling procedures. Those are described in detail per interface starting with LTE Systems radio access network architecture and signaling, as well as the EPS Bearer Service, End-to-End service from QoS aspects. A description of the LTE radio interface is given including an OFDMA introduction.

The course covers the LTE radio access interfaces, such as X2 and S1 and the corresponding controlling protocols X2AP and S1AP.

Also covered in this course are the L3 and L2 protocols and the upper control layers of NAS and RRC are also covered. Further in the course is also included a description for GTP-U and PDCP, RLC, MAC and the physical layer for the radio interface.

Security aspects are also explained such as Authentication and Security Key generation.

The purpose of the course is to enable the students to understand complete traffic case in EPS including CS Fallback.


Learning objectives

On completion of this course the participants will be able to:

  • Explain the EPS Network Architecture
  • Distinguish between the different EPS Protocols
  • Draw a simplified EPS diagram showing the protocols used.
  • Explain the LTE/SAE Quality of Service and Security in LTE
  • Explain the L3 Signaling Protocols
  • Explain the purpose with Non Access Stratum NAS protocol
  • Explain the interaction between RRC and the lower layers in the control plane
  • Explain the RRC Service States and the difference between connected and idle mode
  • Explain the functions and services of RRC such as System Information Broadcast, Paging, Cell Selection and Mobility
  • Explain the main functions and procedures of X2AP signaling protocol.
  • Explain the main functions and procedures of S1AP signaling protocol.
  • Explain the main functions and procedures of the signaling protocol GTP-C.
  • Explain the L2 transport protocols PDCP, RLC, MAC and GTP-U Protocols
  • Explain the PDCP functions and services such as header compression and ciphering
  • Explain the RLC functions.
  • List the different modes of RLC (transparent, unacknowledged and acknowledged mode) and explain the structure of the PDU involved in these cases.
  • Explain the MAC functions such as HARQ, BCH Reception, PCH reception
  • Explain the MAC architecture, its entities and their usage for the mapping of transport channels.
  • List the contents of the MAC Packet Data Unit (PDU).
  • Explain the main functions and procedures of the transport protocol GTP-U
  • Explain Mobility in LTE and describe different cases (X2 Handover, S1 Handover, IRAT Handover)
  • Explain CS Fall Back for Dual Radio UEs


Target audience

The target audience for this course is:

Network Engineer, Service Engineer, Service Design Engineer, Network Design Engineer



The participants should have a general knowledge in cellular systems and radio technology and equivalent knowledge to “LTE Air Interface” course


Duration and class size

The recommended length of the course is 3 days.

The maximum number of participants is 16


Learning situation

This course is based on theoretical instructor-led lessons given in a classroom environment.


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