TABLE OF CONTENTS We begin our examination of the WCDMA air interface by looking at its organization and some of its characteristics. Following the OSI protocol model, radio interface protocols in the UTRAN system can be described by using a layered three-level protocol model. The lowest layer in this interface is the physical layer. Layer 2 consists of the medium access control (MAC), the radio link control (RLC), the broadcast multicast control (BMC), and the Packet Data Convergence Protocol (PDCP) sublayers. Layer 3 includes the following sublayers: radio resource control (RRC), mobility management (MM), GPRS mobility management (GMM), call control (CC), supplementary services (SS), short message service (SMS), session management (SM), and GPRS short message service support (GSMS). These protocols are depicted in Figure 3.1.
As the physical layer is such an important part of the UTRAN system, it is discussed in four chapters. This chapter gives a general physical layer presentation. Chapters 4-6 include a more detailed discussion about some specific physical layer issues (modulation techniques, spreading codes, and channel coding). The other tasks (i.e., layers 2 and 3) in this protocol model are discussed in Chapter 7.
The physical layer is the lowest layer in the WCDMA air interface protocol model. It has to handle slightly different tasks depending on whether it is in the UE or in Node B, but the basic principles presented here are the same regardless of the location.
The physical layer has logical interfaces to both the MAC...
