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)

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

Logical channels define ‘WHAT’ type of information is being transferred and transport channel defines ‘HOW’ the information is being transferred.

In this tutorial different types of logical channels and transport channels and their mappings are described.