tailieunhanh - Các mạng UTMS và công nghệ truy cập vô tuyến P4

THE UTRA PHYSICAL LAYER DESIGN The UTRA design is comprised basically of three parts, . radio aspects corresponding primarily to the physical layer, radio interface aspects incorporating layers two and three, and network aspects inter-working directly with the core network. This chapter describes the UTRA physical layer including both FDD and TDD modes, as well as spreading and modulation, multiplexing and channel coding, and physical layer procedures. | The UMTS Network and Radio Access Technology Air Interface Techniques for Future Mobile Systems Jonathan P. Castro Copyright 2001 John Wiley Sons Ltd Print ISBN 0-471-81375-3 Online ISBN 0-470-84172-9 4 The UTRA Physical Layer Design The UTRA design is comprised basically of three parts . radio aspects corresponding primarily to the physical layer radio interface aspects incorporating layers two and three and network aspects inter-working directly with the core network. This chapter describes the UTRA physical layer including both FDD and TDD modes as well as spreading and modulation multiplexing and channel coding and physical layer procedures. SUMMARY OF FEATURES Figure illustrates the relationship of the physical layer L1 and the upper layers L2-L3 . L1 interfaces the Medium Access Control MAC sub-layer of L2 and the Radio Resource Control RRC portion of L3. L1 offers different transport channels to the MAC and the MAC offers different logical channels to the Radio Link Control RLC sub-layer of L2. Thus there are Service Access Points SAPs between the different layer sub-layers. A transport channel is characterized by the way information is transferred over the radio interface. The type of information transferred characterizes a logical channel. Two types of physical channels are defined in L1 . Frequency Division Duplex FDD and Time Division Duplex TDD . The first FDD mode is characterized by code frequency and in the uplink by the relative phase I Q the 2nd TDD mode has in addition a time slot characterization. The Radio Resource Control RRC manages L1. Figure A radio interface protocol architecture around L1. The data transport services offered to higher layers by L1 occurs through the use of transport channels via the MAC sub-layer. Table illustrates some of the L1 or physical layer services. Through inter-working . a UE provision of compatible bearers is assured. 86 The UMTS Network and Radio Access Technology Based on the types of