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Investigation of the Advantages of TDSCDMA compared to WCDMA. Thesis Presentation 7 Nov 2006. Author: Wang Ying Supervisor: Prof. Sven-Gustav Häggman Instructor: M.Sc. Mikko Nieminen. Agenda. Background Objectives Methodology TDSCDMA physical layer structure
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Investigation of the Advantages of TDSCDMA compared to WCDMA Thesis Presentation 7 Nov 2006 Author: Wang Ying Supervisor: Prof. Sven-Gustav Häggman Instructor: M.Sc. Mikko Nieminen
Agenda • Background • Objectives • Methodology • TDSCDMA physical layer structure • Key technologies used in TDSCDMA • Conclusion • Future study
Background • The developing of GSM system started from early 1980’s • February 1999 Nokia Oyj completed the first WCDMA call through the public switched telephone network in the world. • There are now about 2.9 million WCDMA subscribers. Most of these are in Europe and Japan. • TDSCDMA (Time Division Synchronous Code Division Multiple Access) developed by the China Academy of Telecommunications Technology (CATT), in cooperation with Siemens. Why indeed TDSCDMA encourages Chinese government spent over 10 years' hard work?
Objectives • To investigate the advantages for using TDSCDMA system compared to using WCDMA system • Methodology • Literature research • Discussion with experts
Core Network CN Iu Radio Access Network RAN Uu User Equipment UE Network structure
Radio Resource Control (RRC) Layer 3 SAP Medium Access Control (MAC) Layer 2 CPHY primitives PHY primitives Layer 1 Physical Layer (PHY) TDSCDMA physical layer structure 1/5 • Physical layer interfaces with upper layers
TDSCDMA physical layer structure 2/5 • Physical channel structure
TDSCDMA physical layer structure 3/5 • Subframe structure ( ; )
TDSCDMA physical layer structure 4/5 • Tsn (n from 0 to 6): the normal time slot, 864 chips duration; • DwPTS: downlink pilot time slot, 96 chips duration; • UpPTS: uplink pilot time slot, 160 chips duration; • GP: main guard period for TDD operation, 96 chips duration; • Switching Point: between the downlink time slots and uplink time slots (vice versa )
675 µs Data symbols 352 chips Midamble 144 chips Data symbols 352 chips Guard period 16 chips 75 µs 125 µs Guard period 32 chips SYNC1 128 chips SYNC 64 chips Guard period 32 chips TDSCDMA physical layer structure 5/5 • Normal TS structure • UpPTS structure • DwPTS structure
Key technologies used in TDSCDMA 1/3 • Combined TDD, TDMA and CDMA operation Depending on the Max. used spreading factor • TDD: Separate Uplink and Downlink • TDMA: Separate different users • CDMA: Separate different users
Antenna Array ... TRx M TRx 1 ... ... TRx 2 TRx 3 ... Feed Cables Base Band Processor Key technologies used in TDSCDMA 2/3 • Smart antenna • Rx (Uplink): find the best • Tx (Downlink): beamforming can greatly reduce the interference to other co-channel UEs also can save output power
Conclusion • 1.6 MHz unpaired frequency band – efficient spectrum usage • TDD, TDMA and CDMA combined operation – better supporting data services • Using smart antenna – efficient suppressing interference • No cell breathing – easier network planning
Future Study • Study TD-SCDMA network performance • Study the disadvantage in TD-SCDMA system Thank You!
AppendixDifferent Radio Modes with Harmonized Parameter Sets