TD原理及综合组网.pptVIP

COM TD training TD-SCDMA BASIC INTRODUCTION FOR Zhongxun NPDI Issued by Zhang haijun Overview IMT – 2000 Family Members Optimum Spectrum Efficiency Overview CDMA Principle Data Block 1 Data Block 2: 352 chips Midamble: 144 chips, including 16 cyclic prefix 128 basic midambles with length 128 chips Used for channel estimation, SIR measurement , maintaining uplink synchronization and frequency offset correction Guard period: 16 chips Guard Interval (96 chips) Spreading Codes Basic Scrambling Code (by chip) Scrambling Codes: 128 codes with Qmax=16, used for randomizing the user data signal on the basis of chips and improving cross correlation of spreading code, which will be divided into 32 groups, each contains 4 codes which is corresponded to one midamble; One scrambling code corresponds to Qmax/Qk data symbols Relationship between Codes Benefit to frequency regulation administration: Assignment of only one frequency band required. Benefit to network operators: 1. Allowing adaptive radio resource allocation to Downlink and Uplink 2. Adaptation of radio resources to user caused traffic requirements 3. Optimum traffic load and spectrum utilization independent of service Benefit in System Design: 1. Enabling system-inherent flexible radio resource allocation. 2. Flexible operation of symmetric and asymmetric services without additional hardware. 3. Low hardware complexity in base stations and mobile stations. TD-SCDMA combines 4 Multiple Access Techniques – Hybrid Multiple Access Logical, Transport Physical Channels:Definitions Channel concepts: Logical Channel: defines “which” kind of information is transferred (Broadcast signalling; Common signalling; Paging; Dedicated Signalling; dedicated user data ...). Logical Channels apply between higher layers and MAC layer. Transport Channel: defines “how” the Logical Channel has to be delivered over the air (which channel coding; TTI ...). Transport channels apply between MAC and Layer1. Physical channel: