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giải pháp DAS mimo trong hệ thống viễn thông Giải pháp SC MIMO bao gồm hai thành phần chính: Head Unit (HU) và Service Unit (SU). Các thành phần cần thiết khác là Bộ lọc DC+IF và Bộ ghép DC Pass.
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Overview of DAS Solutions
15-Jul-2017
Trang 2▪ In-Building Design Trends
▪ Marketplace Solutions and Building Types▪ Approaches to In Building System Design
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In-Building Design Trends
▪ Network Operators Prefer Passive Solutions
▪ Radiating cable now widely used
▪ Fibre optic technology used only where necessary▪Solution for large buildings
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Trang 4Passive and Active DAS
Passive Solutions
Active Solutions
MainHub
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Why Use Distributed Antenna?
▪ Applicable where narrow range of frequencies are required and future expansion into other bands is not anticipated
▪ Single or Dual band systems.
▪ To provide hot spot coverage of open areas.▪ Highly cost effective.
Trang 6Why Use Radiating Cable?
▪ Flexibility / Cost- Effective Upgrading ▪ Broadband capability
2700MHz
▪ Advantages of leaky cable
▪Less close / far signal difference.
▪ Disadvantages of leaky cable
▪Difficult to match with interior design.
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Radiating Cable vs Antenna
▪ Major issue is the topology of the required coverage area.
rectangular or circular disposition.
and narrow office spaces such as those wrapping around the core of a high rise building.
▪ A radiating cable solution is generally more costly (material wise) than an antenna solution.
▪ Flexibility / Cost
unlimited number of services ranging from 1MHz to 2500MHz.
later without further installation costs.
would require a new antenna system.
Trang 8Antennas vs Radiating Cable
Radiating CableCoverage
Signal Strength
Distance
Trang 9▪ High system reliability
Active System
▪ Active systems overcome insertion loss, restoring antenna EIRPs and uplink system noise figure
▪ Duplex cellphone systems require elaborate and relatively expensive linear BDAs
▪ Linearity is critical; multiple carriers escalate 3OIP and power rating of downlink PAs
▪ Multiple radio platforms necessitate band-dedicated BDAs
Trang 10Passive DAS for LTE-A?
Pros of Passive DAS
▪ An all-passive coaxial cable system is highly linear
▪ Capable of handling multiple downlink carriers with no measurable IM products
▪ High system reliability.
Cons of Passive DAS
▪ Feeder cable size is typically limited to 7/8” or 1-5/8”▪ Not suitable for buildings that require long feeder runs▪ At high frequencies, the system loss becomes very high
▪ Lower DL coverage, poorer uplink sensitivity and reduced SNIR
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Hybrid DAS
▪ Most cost effective solution
▪ Difficult to manage uplink active systemfrom interfering with passive DAS
Hybrid Solutions
Master Unit
Coaxial Cable toAntennas
Coaxial Cable
RemoteUnitRF Repeater
Radiating CablesRadiating Cables
Coaxial Cable to Antennas
Coaxial Cable to Antennas
Donor BTS
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Trang 12Hybrid DAS Application Scenarios
1 Multi StorySkyscraper
Rad Cable
3 Campus Environment
Fiber OpticsRemote Unit
Fiber OpticsRemote Unit
Fiber OpticsMaster Unit
2 ShoppingCenter
Attached High Rise BuildingFiber
Master UnitFiber Optics
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Optimum Amplifier Placement
▪ Best results when amplifier is placed near to antenna.
▪UL NF is minimized, i.e better sensitivity
▪ Trade-off between how close amplifier is placed to the antenna, and number of amplifiers needed.
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Trang 14Optimum Amplifier Placement
▪ Scenario 1: No Amplifier
BTS NF plus cable loss
▪ Scenario 2: Amplifier Near the Antenna
between BTS and amplifier.
System Noise Figure = 50 dB
System Noise Figure = 16.2 dB
RXNF = 10dB
Overall NF16.19dB
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Optimum Amplifier Placement
▪ Scenario 3: Amplifier Far from Antenna
▪ Amplifier gain compensates for feeder loss and thereby increasing performance.
System Noise Figure = 50 dB
RXNF = 10dB
Stage 1 Stage 2 Stage 3 Stage 4
Overall Gain-5dBOverall NF50dB
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Trang 16NFh
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Approaches to ImplementCoverage Solutions
Trang 18Coverage Solutions
RF Repeater, Pico Repeater + DAS
E.g., Small Restaurant and Building
RF Repeater, Booster + DAS
E.g., Supermarket, Residential Building
BTS + DAS
E.g., Office Building, Shopping Mall
BTS + Fiber Repeater / Booster + DAS
E.g., Airport, Megamall
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High Capacity + Small Coverage Applications
WCDMA BTSDCS BTSGSM_B BTS
GSM_A BTS
Basement Car ParkTPX
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Trang 20High Capacity + Large Coverage Applications
▪ Fiber optic repeaters are often used for large scale in-buildings where high coverage and capacity are needed.
▪ Typical applications are in airports, underground metros, exhibition halls, campus buildings, etc.
Trang 21Donor Antenna
Trang 22Low Capacity + Large Coverage Applications
Optical Repeaters
ANTOptical Fiber
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Low Capacity + Small Coverage Applications
Small OfficeDonor
▪ Using Indoor Pico Repeater
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Trang 24Summary
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▪ The new Rosenberger Smart DAS solution can provide a flexible solution for a high power hybrid DAS and low power active DAS.
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Trang 26THANK YOU
www.rosenbergerap.com