Indoor Coverage
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Description
Indoor Coverage Solutions
V. Merle RF Solutions Engineer GSM Solutions 06/17/99
Indoor Solutions Objectives
Indoor Market includes a wide range of applications for operators
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Indoor Solutions Objectives
Indoor Market includes a wide range of applications for operators
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Agenda • Indoor Coverage Solutions – Indoor Solutions approaches – RF distribution System
• Indoor Radio Dimensioning • Corporate Coverage Specificity • Indoor Design Process Outlines • Indoor Realizations – Example : Corporate Coverage with PicoNode
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Indoor Coverage Solutions
Which Indoor Solution ?
Source
? 4
Macrocell & Indoor Application
Macrocell Densification
• Indoor coverage improvement, especially for higher floors
• Difficulty to get perfect indoor coverage, especially for low floors, underground parking & deep indoor • No extra capacity extension if not taken into account from the start
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Microcell solution
• Good coverage solution, especially for lower floors • High capacity solution • High spectrum efficiency Higher sites density
• High density of sites higher cost • Problem of dimensioning the macro/micro cell in order to cope with building generated traffic • Localized solution Macro • Problem of atypical areas µ
cell
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Repeater solution Extension of the outdoor coverage coming from a macro/micro cell
• Coverage everywhere in indoor areas • Fast & low cost solution
• No extra capacity Possible overload of the serving cell • Limited power solution • Possible BTS blocking & BTS desensitivity Fine tuning of repeater amplifier gains 7
Picocell solution
Dedicated cells for the considered buildings
• Coverage everywhere in indoor areas • Capacity extension into indoor areas • Highest spectrum efficiency
• Higher design load : specific design for specific building
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Indoor System Repeater
Indoor Objectives - Good coverage - Good quality - Traffic capture * DAS
2 key points - BTS source - RF system
BTS
RF system
DAS : Distributed Antenna System
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Indoor Issue Indoor Objectives Good coverage Good quality Traffic capture
Indoor/Outdoor Interference
How to Integrate the Indoor cell in your Network ? - in terms of interference - in terms of traffic capture - in terms of Handover
Indoor cell resurgence
Field strength Competition Outdoor cell
Indoor cell
Maximize Indoor field strength, Minimize Outdoor leakage 10
RF Distribution System Repeater & Picocell solution specific
Coaxial cable • + Antenna • + Leaky feeder
Distributed Antenna System • Optic Fiber DAS • CATV • Coax + Power Amplifier
Distributed Base Stations (DBS)
System choice depends on :
• Building form & size • Required capacity/coverage/quality • Available spectrum • Installation constraints • Reuse of existing infrastructure • Resources constraints • Cost 11
Indoor RF system Existing infrastructure Confinement request
• Coaxial feeder (antenna / leaky cable) — widely used solution — large band system — low hardware cost — installation constraints and costs
• Optic Fiber System (DAS) Interference competition 2 Main Technologies
— new technology — possible optic infrastructure reuse — high hardware cost — low installation cost & constraints — low EIRP distributed antenna approach
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Coaxial cable + Antenna
— Expectation of high EIRP — Wide area to cover
Sufficient power to guarantee antennae EIRP & compensation of feeder losses
Careful attention on source position to ensure coverage over targeted area
— For small building coverage (3-5 floors) or small distribution distance (100 m)
— Localized source : careful attention on proximity of apertures to minimize outside leaking — Limited deployment system — Installation constraints
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Coaxial cable + Leaky feeder
— For small building coverage (3-5 floors) or small distribution distance But no strong signal … Jammer overcome ?
— Homogeneous indoor coverage — Very low outside radiation application — Good confinement possibility
New solution : Flat Strip Radiax
— Installation constraints
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Optic Fiber System (1)
• Various OEM Fiber distributed antenna solutions — Monomode Use of fiber optic cables for signal distribution
— Multimode
• Nearly identical RF performances • Best solution criteria : — material & installation cost
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Optic Fiber System (2) — Low-loss low-noise fiber optics transceivers for signal conversion — For huge building (> 5 floors) & wide distribution distance (1-2 km) with no attenuation
Appropriate In- building coverage for scattered buildings
— Possible infrastructure reuse — Low installation cost and constraints – – – –
ease of installation small discrete flexible cable no bulky feeder trays required minimal disruption to functions or staff
— Low output power & same low EIRP for all connected antennas — Critical deployment speed — Higher hardware cost
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Indoor Radio Dimensioning
How to dimension the Indoor network ?
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Indoor Solution
2 dimensioning points - Capacity - Coverage
• Build your Indoor solution considering : — Capacity needs
t ySpectrum availability i— c a C a p — Frequency Planning — Quality of Service — Coverage requests
n g i Interference control — s e d R F — Building architecture — BSS features
BTS & RF system
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Capacity dimensioning • Repeater / BTS Constraints Who is the targeted user? Which quality of service ?
— Traffic needs & capacity evolution — Spectrum availability — Possible frequency planning — Power requirement issues — Installation issues
• Nortel Networks Solutions What spectrum can be used?
Capacity solutions First input for RF design
Power solutions
• Small Capacity :
• Low Power :
• 2 TRXs S2000L / H • up to 3 TRXs Corporate Piconode & distributed pBTS portfolio • High Capacity : S8000
• 2W & 8W Piconode BTS • 2.5W S2000L • High Power : • 24W S2000H • 30W S8000 19
Frequency Plan • Spectrum reuse
High spectrum efficiency possibility
— 3 dimensional frequency planning — by floor — from floor to floor
MA1 MA2
• Fractional reuse
— MAIO / HSN allocation per building / floor
Three dimensional frequency planning
Frequency Hopping
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Spectrum sharing 1 single band for the whole network Outdoor + Indoor Nortel solutions: BCCH plan AFP TCH plan Fractional reuse
• Single band for outdoor and indoor Outdoor
µ
cell
Indoor
Whole spectrum for the network
Is there dedicated spectrum for indoor, how much ?
• Designing indoor radio network with spectrum constraints – Careful borrow from distant macro cells for indoor frequencies – Efficiency of the coverage confinement
Spare frequencies for indoor
• Optimized outdoor spectrum utilization can save some spare frequencies for indoor design 21
Design Constraints
• Installation constraints — Accessibility — Distributed system : feeder runs, feeder trays … — Antenna type (omni, panel, …)
• Minimize Cost — Equipment : BTS system, feeders, splitters, antennas, connectors, amplifiers, … — Installation — Maintenance (distributed system, active elements, …) — Transmission / Power, equipment room (leasing)
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Corporate Coverage Specificity
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Indoor Operator Approach • Corporate Service Offer — Commitments on QoS for a specific end-client
Operator interests
— Deskset / gsm mobile interoperability — Dedicated sub-network — PBX like Services
One solution dedicated to one building
• Corporate Coverage — High quality of Coverage / QoS Improvement — Good voice quality — Traffic Capture — Part of PLMN Network Extension / Optimization
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Corporate Coverage Specificities • Type of customers (operators, building owner, company representatives, …)
• Specific Corporate environment • High QoC & high QoS expected : corporate coverage should be optimum
• Capacity availability — Specific subscriber : high penetration rate (~ 50%) — Specific corporate call profile
• Specific features : — dialing plan, specific billing, PBX extension, supplementary services, data ...
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Indoor Design Process Outlines
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Indoor RF Design Process 2 Strategies : • Careful design Measurements mandatory • Fast design only Optimization
Cooperation needed with : • Building owner • Site engineer • I&C team
a s e h P s i s i t e u q e P r e r
1- Customer requirements 2- RF prerequisites
RFM Measurements & Site survey
3- BTS / Repeater choice
h a s e P n e s i g D F R
4- RF design 5- RF validation
a s e h P t n y m e o l p D e m e t s S y
RFM Measurements Simulations I&C
7- System deployment
8- System validation
* Example for 3-5fl buildings
RSV Measures
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Indoor realizations
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Example 1 : Coax + Antenna Downlink
Uplink
BTS parameters
34 dBm
-104 dBm
Hybrid coupler
3 dB
Jumpers
1 dB
Coax
2*1:2 splitter
6 dB
Splitter
50 m coax cable + connectors 6 dB
Solution widely used in HK, Singapore,..
S2000
Antenna
3 floors building, S2000L
2dBi antenna
2 dBi
RF Distribution loss
13 dB
Slow mobile margin
6 dB
Body loss
3 dB
Mobile antenna gain
2 dBi
Mobile parameter
33 dBm Downlink
Uplink
Worst Link budget
112 dBm 112 dBm
115 dBm limited Downlink
Indoor minimum field
-91 dBm
propagation attenuation : 11.5 dB/100m
EIRP antenna #1
23 dBm
Limiting point : RF distribution loss
EIRP antenna #2
20 dBm
EIRP antenna #3
19 dBm
Design Threshold
-78 dBm
• 7/8“ foam coax cable propagation attenuation : 4.2 dB/100m
• 1/2” superflexible coax cable
13 dB (50m 1/2 ’’ + 2 splitters)
Total Link
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Example 1 : Coax + Antenna Solution used in UK, Singapore
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2 -3 dB
19.5 dBm
-1 dB
3 -3 dB
-1 dB
-1 dB
Splitter 1*2
BTS S2000L
-1 dB
Antenna -1 dB
Antenna location - EMC risks - MPE limits - Blocking
29.5 dBm (-10) 14.5 dBm
10.5 dBm
10.5 dBm
Bidirectional amplifier/ repeater for huge deployment scale Power splitter usual or directional
Amplifier gain to be tuned carefully Impact on Noise figure and sensitivity
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Example 2 : Corporate Coverage with PicoNode
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Corporate Offer • NORTEL provides a dedicated Corporate approach with PicoNode ensuring one local GSM Switching with PBX connection to provide one unique solution to end-users.
• This solution is somehow equivalent to one Combo : MSC/BSC/BTS in one box
small sized GSM system as it integrates MSC, BSC & some BTS in one really compact system.
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Corporate Coverage with PicoNode specificities (1) • Picocell traffic management — The objective is to save some resources of the picocell; nonCorporate subscribers must be directed to the macrocellular network.
Future effective solution [R6] : SOLSA
— Need for “better field strength” approach implying accurate RF design & tuning – careful attention on frequency plan change – careful attention on new BTS introduction
• HO characteristics — Handover facility requested to ensure a seamless service at entrance points. — No HO Ping-Pong between the Picocell & the Macrocell.
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Corporate Coverage with PicoNode specificities (2) • Frequency sharing 2 key points
— Leakage issues – from “no specific attention” to “no field radiated outside”
specific requests of radio thresholds : highest limit for outside radiation (e.g. -90 dBm@50%)
• Leakage • Spectrum
— Spectrum issues – dedicated spectrum or reuse of some spectrum used outdoor macrocells :
number of frequencies = number of TRXs
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Piconode Datafill Parameters Setting (1) • Favor selection & reselection towards the PicoCells : same celltype as PLMN cells
2 users types (public & hybrid)
Piconode network for all mobiles entering in the corporate building – RxLevAccessMin(pcells) 90% (12dB)
• Link Budget
Leaky feeder input power
20 dBm
End Leaky feeder power
9.5dBm
Design Threshold
-73dBm
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LGC Distributed Wireless Access • Main Hub • Up to 4 Expansion Hubs • Multimode fiber up to 1Km • +10 dBm maximum input power for O1 • +7 dBm maximum input power for O2
Expansion Hub r e b i F
e r F i b
U T P o r S T P
Expansion Hub U T P o r S T P
Coax
Fiber Main Hub F i b er
pBTS • 1 FMH per pBTS
Expansion Hub U T P o r S T P
F i b e r
Expansion Hub U T P o r S T P
• Antenna Hub • Expansion Hub • Supports up to 4 Antenna Hubs • Distributes RF over UTP/STP Cat 5
• UTP or STP in (RJ45) up to 50 m • Loop powered via UTP or STP • Coax out (SMA)
• Antenna : 3 / 7 dBi
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