WCDMA AND WLAN FOR 3 G AND BEYOND
WCDMA AND WLAN FOR 3 G AND BEYOND 通訊所 研二 691430042 楊川民
Outline n n n n Introduction Glossary UTRAN FDD Mode: WCDMA UTRAN TDD Mode: TD/CDMA WCDMA Evolution From 2 G to 3 G Three Phases From Release 99 and Release 4 to Beyond 3 G Conclusion
Introduction
Glossary n n n n n FDD: Frequency Division Duplexing WCDMA: Wideband Code Division Multiple Access TDD: Time Division Duplexing TD/CDMA: Time Division / Code Division Multiple Access GSM: Global System for Mobile Communications 3 GPP: Third Generation Project Partnership HSDPA: High Speed Downlink Packet Access HS-DSCH: High Speed Downlink Shared Channel UMTS: Universal Mobile Telecommunications System
UTRAN FDD Mode: WCDMA
UTRAN FDD Mode: WCDMA (cont. ) n n n Figure 2. 1 illustrates some of the UTRA Frequency Division Duplexing (FDD) characteristics. This mode uses Wide-band Direct-Sequence Code Division Multiple Access (DS-CDMA), denoted WCDMA. To support bit rates up to 2 Mbps, it utilizes a variable spreading factor and multi-code links.
UTRAN TDD Mode: TD/CDMA
UTRAN TDD Mode: TD/CDMA (cont. ) n n The 2 nd UTRA mode results from the combination of TDMA–FDMA and exploits spreading as part of its CDMA component It operates in Time Division Duplexing (TDD) using the same frequency channel In this mode, the MSs can only access a Frequency Division Multiplexing (FDM) channel at specific times and only for a specific period of time Hence, in the TDD mode we define a physical channel by a code, one TS, and one frequency, where each TS can be assigned to either the uplink or the downlink depending on the demand
WCDMA Evolution From 2 G to 3 G n WCDMA q q n support of multiple simultaneous service Higher data rate than GSM q q Not support of multiple simultaneous service evolution parallel with WCDMA
Three Phases From Release 99 and Release 4 to Beyond 3 G n Phase 1: High-Speed Downlink Packet Access (complete in 2001) q HS-DSCH, inherit many of the features of the DSCH defined in release 99 n Main proposed technical enhancement q q Adaptive Modulation and Coding (AMC) Fast Hybrid Automatic Repeat Request (FHARQ) Fast Cell Selection (FCS) HSDPA, released as part of release 4, completed in release 5
Three Phases From Release 99 and Release 4 to Beyond 3 G (Cont. ) n Phase 2: Uplink High-Speed Data, High-Speed Access for TDD (not approved) q n Emphasis air interface optimization in the area of downlink high-data-rate support and attention uplink Phase 3: Capacity Improvements in Uplink and Downlink, and Further Data Rate Enhancement (not approved) q Some of the foreseen air interface technologies become mature in a timeframe that may be unacceptable for the proposed phases 1 and 2 of WCDMA development
Future Challenge in WCDMA and WLAN n n n Data-intensive application need high data rate environment How spreads bandwidth in new frequency allocations How used to mobile business q Established roaming agreements for WLAN network subscriber management
Other Tread in the Next-Generation n n Mobile business need an efficient way to access corporate information systems and databases remotely through the Internet backbone Cover the demand for data-intensive applications and enable smooth online access to corporate data services in hot spots
Potential in WCDMA and WLAN n In hot spot environments q n In business environment q q n Application and service that need high data rate E-commerce Fee service In UMTS and UTRAN q Used WCDMA FDD and TDD achieve larger cell size and cost saving
Coupling of Air Interface
Beyond 3 G to 4 G n Issue in 3 G evolution q n It need to support IP and IP-based multimedia 4 G is a revolution of the air interface rather than a new phase of evolution q They have different access method
The Revolution Toward 4 G
Conclusion n n The WCDMA air interface is seen to develop far beyond its initial capabilities to satisfy future service and application needs No time to fine answer that can overcome the issue in 3 G, we want to fine in 4 G
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