7
Radio Interface Protocols
7.1 Introduction
The radio interface protocols are needed to set up, reconfigure and release the Radio Bearer (RB) services (including the Universal Terrestrial Radio Access (UTRA) Frequency Division Duplex (FDD)/Time Division Duplex (TDD) service), which were discussed in Chapter 2.
The protocol layers above the physical layer are called the data link layer (layer 2) and the network layer (layer 3). In the UTRA FDD radio interface, layer 2 is split into sublayers. In the control plane, layer 2 contains two sublayers: the Medium Access Control (MAC) protocol and the Radio Link Control (RLC) protocol. In the user plane, in addition to MAC and RLC, two additional service-dependent protocols exist: the Packet Data Convergence Protocol (PDCP) and the Broadcast/Multicast Control (BMC) protocol. Layer 3 consists of one protocol, called the Radio Resource Control (RRC), which belongs to the control plane. The other network layer protocols, such as Call Control, Mobility Management, Short Message Service (SMS), and so on, are transparent to the Universal Mobile Telecommunication Services (UMTS) Terrestrial Radio Access Network (UTRAN) and are not described in this book.
In this chapter, the general radio interface protocol architecture is first described before going into deeper details of each protocol. For each protocol, the logical architecture and main functions are described. In the MAC section (Section 7.3) the logical channels ...
