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Overview
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Frequency bands
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Band I
channels 9512 – 9588
channels 10062 – 10113
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1900 to 1920 MHz
2010 to 2025 MHz
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Band II
channels 9262 – 9538
channels 9662 – 9938
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1850 to 1910 MHz
1930 to 1990 MHz
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Band III
channels 9562 – 9638
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1910 to 1930 MHz
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Channel raster
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200 kHz (1.6 MHz channel spacing)
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Channel bandwidth
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1.6 MHz
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Modulation
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QPSK, 8PSK, 16QAM
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Chip rate
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1.28 Mcps
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Access format
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CDMA/TDMA/TDD
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Receiver
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NodeB: Joint Detection
UE: Rake
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Spreading factors
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DL: 1 or 16
UL: 1 to 16
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Frame structure
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2 sub-frames per TDMA frame (10 ms)
7 timeslots per sub-frame (5 ms)
864 chips per time slot, equivalent to 675 µs
symmetric/asymmetric operation
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Data rate
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CS: 12.2 kbits/s, 64 kbits/s, 144 kbits/s,
384 kbits/s, 2048 kbits/s
PS: 9.6kbits/s, 64 kbits/s, 144 kbits/s,
384 kbits/s, 2048 kbits/s
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Speech
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Adaptive multirate (AMR), data rate
(4.75 kHz to 12.2 kHz) depending on cell capacity and reception quality
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Power control
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Yes, in 1, 2 or 3-dB steps
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Applications
Time Division Synchronous CDMA (TD-SCDMA) was developed by the Chinese Academy of Telecommunications Technology (CATT) and Siemens, recommended by China Wireless Telecommunication Standards group (CWTS) and approved by the ITU in 1999.
First TD-SCDMA networks are rolled out in China and provide the following advantages:
- High spectrum efficiency by using one frequency band for uplink and downlink and by providing asymmetric data services. Beam-steering smart antennas, joint detection and dynamic channel allocation minimise radio interference leading to outstanding spectrum efficiency.
- Services optimally suited for asymmetric 3G applications: Real time applications, such as voice, use circuit-switched transmission, whereas non real-time applications, such as email, require packet-switched transmission using data rates up to 2Mbps.
Technology in brief
TD-SCDMA uses the Time Division Duplex (TDD) mode, which transmits uplink traffic and downlink traffic in the same frame in different time slots. That means that the uplink and downlink spectrum is assigned flexibly, dependent on the type of information being transmitted. When asymmetrical data like email and internet are transmitted from the base station, more time slots are used for downlink than for uplink. A symmetrical split in the uplink and downlink takes place with symmetrical services like telephony.
Typical measurements
Numerical measurements: Mean and peak power, frequency error, occupied bandwidth, modulation quality (EVM)
Graphical representations: power vs. time, constellation display, modulation spectrum (Adjacent Channel Leakage Ratio - ACLR, Occupied Bandwidth – OBW, Spectrum Emission Mask - SEM)
Willtek Test Instruments
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