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GSM equipment

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Reference

• Ericsson GSM RBS 2000 Basics (student Text EN/LZT 123 3805 R2A)

• 遠傳電訊教育中心 GSM Basic Training Material, http://www.fetec.org.tw

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GSM System StructureSS

BSSMS OMC

BSCRBS

AUC

HLREIR

ILR

GMSC

DTI MSC/VLR

PSTNPSTN

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Radio Base Station

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Radio Base Station

TRU CDU

Antenna

ECU PSU

TRU

Main supply

Battery supply

To BSC

DXU

• DXU: Distribution Switch Unit• TRU:Transceiver Unit• CDU:Combining and Distribution Unit• ECU: Energy Control Unit• PSU: Power Supply Units

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TRU:Transceiver Unit

• One TRU handle 8 air time slots• Perform Channel Coding,

Interleaving, Ciphering, Equalization• One transmit output, two receive

inlets

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Transmission between RBS & BSC

• Enhancement of transmission network

B SC

R B S

BSC

RBS

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Transmission between RBS & BSC

• Building access network is expensive• Chain and Tree structures Vs. Ring and Mesh

BSC

RBS

Ring

BSC

RBS

Protection

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Antenna

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Omni-directional Antenna

GSM 900

GSM 1800

Lightning conductor

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Directional Antenna

GSM 900

GSM 1800

Lightningconductor

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Directional Antenna

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Antenna Diversity• Two independent

antennas receive the same signal

• Space Diversity: Two antennas are separated in a certain physical distance

• Polarization Diversity: Two different polarization arrays in an antenna unit

Horizational array

Verticalarray

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Indoor Leakage Coaxial Cable

Leakage coaxial cable

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Indoor antenna

Omni-directional antennaDirectional patch antenna