The STATUS PDU is used to exchange status information between two RLC AM entities.

In this tutorial following topics are discussed:

  • Why STATUS PDU is required?
  • Status PDU Parameters
  • Different type of SUFIs
  • SUFI ACK described with an example
SRNS Relocation in UMTS Network

SRNS relocation is a procedure used during mobility scenarios when Control of the Serving Radio Network Subsystem (SRNS) is changed to another Radio Network Subsystem (RNS)

In this tutorial following topics are discussed:

  • Relocation Procedure
  • Serving RNS Relocation Procedure
  • Combined Hard Handover and SRNS Relocation Procedure
UMTS Security: Entity Authentication

Entity authentication is the procedure of mutual authentication of UE or USIM and the network.

In this tutorial following topics are discussed:

  • What is Entity Authentication?
  • Authentication Vectors Generation
  • Authentication Procedure
  • Message sequence from UE point of view
MAC PDU Structure for non-HSPA Transport Channels

This tutorial describes about the MAC PDU structure when HS-DSCH and E-DCH transport channel are not used.

MAC PDUs are also called the MAC Transport Blocks (TB). MAC PDU is a bit string. The MAC PDU is consists of the MAC header and the MAC SDU (RLC PDU)

UMTS: RLC Length Indicator (RLC LI)

The Length Indicator is used to indicate, each time, the end of an SDU occurs in the PDU. The Length Indicator points out the number of octets between the end of the last Length Indicator field and up to and including the octet at the end of an SDU segment.

This tutorial gives detail description about RLC AM and UM data PDU encoding.

MAC (Medium Access Control) Architecture (25.321)

MAC is a layer 2 protocol in the UMTS Access Stratum. MAC has the input as logical channels and at the output it has transport channels.
This tutorial covers only the MAC architecture.

The following sections are covered

  • MAC Architecture – UE Side
  • MAC Architecture – UTRAN Side