SMALL CELLS BIG IMPACTS: PERFORMANCE IMPROVEMENTS ...
Transcript of SMALL CELLS BIG IMPACTS: PERFORMANCE IMPROVEMENTS ...
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COPYRIGHT © 2014 ALCATEL-LUCENT. ALL RIGHTS RESERVED.
SMALL CELLS – BIG IMPACTS:
PERFORMANCE IMPROVEMENTS & DEPLOYMENT CHALLENGES
Amit Mukhopadhyay, Ph. D. Director, Wireless Network Modeling & Optimization Bell Labs – Corporate CTO Organization +1 908 582 2911, [email protected] May 16, 2014
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1. Introduction
2. Use Cases
3. Deployment Strategies
4. Cost Model
5. Summary Leanings
AGENDA
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WHAT ARE SMALL CELLS?
•Small footprint, lightweight, small volume, low power
•“Plug and play” enabled
•Low CapEx and OpEx
Source: Award Solutions/LTEUniversity.com
SMALL CELL CHARACTERISTICS ARE SIMILAR TO WI-FI ACCESS POINTS
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HOW ARE SMALL CELLS USED?
•Indoor and outdoor deployment
•Capacity, coverage and performance
•Operator controlled, licensed or unlicensed band
Source: Small Cell Forum
MULTIPLE ENVIRONMENTS SUPPORTED BY APPROPRIATE FORM FACTORS
USE PURSUANT TO COMPANY INSTRUCTION 5
SMALL CELLS PROVIDE CAPACITY AND USER EXPERINCE EFFICIENTLY
TRAFFIC DEMAND PUSHING MACRO CAPACITY TO THE LIMITS
SMALL CELLS ARE A TECHNICAL NECESSITY
2
4
-5 +5 +15
Peak d
ata
effic
iency (
bps/H
z)
Signal-to-noise ratio (dB)
Limits of 2G, 3G, 4G
Shannon Bound
Infeasible region
EV-DO
LTE
HSDPA
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Use Cases
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SMALL CELL USE CASES
COVERAGE
HOLES
QoE
IMPROVEMENT HOTSPOT CAPACITY
LAYER
COVERAGE AND CAPACITY TARGETED FOR INDOOR OR OUTDOOR
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USE CASE 1 : COVERAGE HOLES
Use Economical coverage solution for isolated
areas
Deployed individually or in self-organized
groups
Seamless mobility within Metro Cell group
Opportunistic approach
Targeted Segments Macro coverage holes
Rural retreats and camp sites
Benefits Extended coverage with lower TCO
Improved QoE
No “dead zones”
COST-EFFECTIVE COVERAGE FOR “DEAD ZONES”
Advantages Versus Repeaters :
- No radio cabling (Uses existing
power and Ethernet connections)
- Brings capacity (no power reuse)
- Plug and Play
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USE CASE 2 : HOTSPOT
Delivers dedicated capacity directly to where it is needed
Use Used in urban hotspots
Deployed individually or in self-organized
groups
Seamless mobility with macro and small cell
networks
Targeted Segments Buildings: outdoor to indoor
Train stations and subway stops
City squares
Stadiums or arenas
Benefits Extended capacity with lower TCO / No need
for addition antennas
Improved QoE
Increased uptake of data services
Advantages Versus Pure
Macro Approach:
- Simpler installation
- Green deployment
- Targeted capacity
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USE CASE 3 : CAPACITY LAYER
Advantages Versus Pure
Macro Approach:
- Improve user experience.
- Offloads macro capacity.
Improves QoE at cell edge – adds capacity
Use Used in various morphologies
Deployed individually or in self-organized
groups
Seamless mobility with macro and small
cell networks
Targeted Segments Macrocell edge
Benefits Extended capacity with lower TCO
No need for addition antennas
Improved QoE
Increased uptake of data services
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USE CASE 4 : INDOOR QOE IMPROVEMENT
Use Improves public indoors coverage
Fills in gaps within macro network
Deployed individually or in self-organized
groups
Seamless mobility with macro and small cell
networks
Targeted Segments Shopping malls, event centers and government
buildings
Train stations and subway stops
“Urban canyons”
Buildings: outdoor to indoor
Benefits Extended coverage, indoor and outdoor, with
lower TCO
Improved QoE
No “dead zones”
“5 Bars” Coverage Everywhere
Advantages Versus DAS :
- No radio cabling (Uses existing
power and ethernet connections)
- No need for equipment room
- Brings capacity (no power reuse)
- Better power efficiency
- Plug and Play
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Assumptions from
TR36.814 adapted to
700 MHz
# of metro cells per
macro uniform user
distribution hotspot user
distribution
1 17% 193%
2 40% 300%
4 85% 467%
10 212% 960%
Percent Gain in Median User Throughput
1732m ISD, 2x5W pico cell
100m hotspot cluster radius
(compared to macro only)
RELEASE 8/9 SHARED CARRIER HETNET STUDIES
Planned deployment in traffic hotspots
Macro eNB
Small Cell Pico Cell
• Full cell splitting gains with hotspot
scenarios: 5x increase in # of cells
leads to 5x increase in throughput
• With uniform spatial traffic
distribution, 5x improvement in # of
cells leads to less than 2x
improvement in throughput
SMALL CELLS BRING SIGNIFICANT IMPROVEMENT IN USER EXPERIENCE
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METRO CELLS ARE NOT AN EXTENSION OF THE MACRO THE ECOSYSTEM, TOOLS, REQUIREMENTS, AND MORE ARE ALL DIFFERENT
Metro cells need to: • Be deployed in different scenarios of
spectrum arrangements
• Deal with high number of mobility events
• Deal with large numbers of macro cells –
sniffing for cell size and interference
• Reduce macro-to-small cell ping-pong
• Have high availability
• Operate in a variety of environments
HETNET BRINGS NEW TECHNICAL, OPERATIONAL AND ECONOMIC CHALLENGES
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Deployment
Strategies
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METRO CELLS: THE NEED
• With mobile data explosion, network
costs are increasing much faster than
revenues
• In many markets, macro cells are
already very close to each other and
spectrum is getting exhausted
• Radiation concerns and zoning
restrictions are making macro cell adds
more and more difficult
Macro Cells Macro Cells + Small Cells Thro
ughput
WHAT IS THE OPTIMAL MIX OF TECHNOLOGIES?
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IMPORTANCE OF TARGETED DEPLOYMENT
• 2%-3% users generate 40%-50% of mobile
data traffic
• 60% - 70% mobile data generated by nomadic
users, indoors
Only a Few Traffic Hot Spots
• Metro cells are small, light weight, low
power
• Their coverage area is often less than 1% of
macro coverage area
Need Precision in Deployment
Traffic:
Traffic Density Map in a Sector in a Large US City
MATCHING TRAFFIC HOT SPOTS WITH SMALL CELL COVERAGE AREA IS CRITICAL
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1. Identify “high runner” candidate sites
based on:
i. Throughput
ii. Performance
2. Run radio network planning tool to
assess macro signal strength
i. Outdoors
ii. Indoors
3. Carry out hotspot analysis
4. Perform offload estimates and
economic analysis matching
throughput requirements, equipment
characteristics with traffic demand
IDENTIFYING CANDIDATE MACROS
TARGETED MACRO DEPLOYMENT
Macro coverage area
Area in “high
runner” sites
Area with
manageable macro
signal strength
Hotspot
area
A SMALL GEOGRAPHIC AREA IS TYPICALLY COVERED WITH SMALL CELLS
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CORNERSTONES OF METRO DEPLOYMENT
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PN
-99.2250 -99.2167 -99.2083 -99.2000 -99.1917 -99.1833
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METRO CELL DEPLOYMENT OPTIMIZATION IS AN ITERATIVE MULTI-STEP PROCESS
Coverage,
interference
Traffic, users Sites,
backhaul
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METRO OUTDOOR FOOTPRINT IN SHARED CARRIER DEPLOYMENT
Macro site location
Metro in
low efficiency zone
Metro in moderate efficiency zone
Metro in
high efficiency zone
•FOOTPRINT SIZE/SHAPE VARIES, BASED ON RELATIVE MACRO-METRO RF SIGNAL STRENGTH
•AMOUNT OF TRAFFIC OFFLOAD WILL VARY BASED ON TRAFFIC DENSITY IN COVERAGE FOOTPRINT
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SHARED VS. DEDICATED CARRIER FOR METRO CELLS
• A dedicated carrier metro cell can cover a much wider area regardless of proximity to the macro
High efficiency traffic offloading without exclusion zones
• Decision should be driven by performance objectives and network economics
Exclusion zone
Low efficiency
zone
Moderate efficiency
zone
High efficiency
zone
Coverage area of metro cells deployed with dedicated carrier
Coverage area of metro cells deployed with shared carrier
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KPIs: Maximize PS throughput, prevent dropped CS, CS+PS calls, and PS calls.
Traffic segmentation: Macro-metro shared carrier only carries PS only (~90% total traffic)
• Metro cells only placed on one carrier
• All CS traffic (i.e. voice) kept on dedicated macro carriers
• All high mobility traffic kept on dedicated macro carriers
TRAFFIC SEGMENTATION FOR NETWORK KPI
3G
1900 MHz
3G
850 MHz
3G
850 MHz
CS & PS traffic
High mobility traffic
Macro + Metro carrier
Macro Dedicated carriers
PS only traffic
Low mobility traffic
3G
1900 MHz Fs
Fd
Fd
Fd
CARRY LOW MOBILITY PS TRAFFIC ON SMALL CELLS
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METRO INDOOR FOOTPRINT IN SHARED CARRIER DEPLOYMENT
SAFE ZONE FOR INDOOR IS SIGNIFICANTLY LARGER THAN SAFE ZONE FOR OUTDOOR PLACEMENT
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INDOOR DEPLOYMENT CONSIDERATIONS
Functional Area Important Consideration
Macro-small cell mobility Specially configured “gateway” small cells needed at all
entrances/exits, elevators, stairwells etc. needed.
In-building macro interference Building interior may experience macro pilot overshoot,
especially close to windows.
Multi-Floor Deployment Metro signal leakage may occur from floors above/below,
depending upon construction material.
Interior environment change Interior RF conditions/capacity demands may change from
time to time.
Exterior environment change New macro cells or reconfigured existing cells may impact
existing indoor coverage
System restart Simultaneous restart after maintenance activity/power outage
may not allow for neighbors to be sniffed and updated.
IN-BUILDING DEPLOYMENT CAN BE INFLUENCED BY OUTDOOR DEPLOYMENT
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SON FOR SMALL CELLS
MLB - Mobility Load Balancing Improve user
experience and reduce dropped calls
Reduce but not eliminate Cell Planning
MRO - Mobility Robustness Optimization
Dynamic eICIC
Auto Neighbor Relation
Auto Configuration of PCI
eNB Self Configuration
RACH Optimization
Dynamic ICIC
Minimization of Drive Test
Manage interference, improve retainability
and accessibility – IOT Control
MASSIVE DEPLOYMENTS CAN ONLY BE SUCCESSFUL THROUGH AUTOMATION
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Cost Model
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METRO CELL DEPLOYMENT WHAT ARE THE LARGEST CHALLENGES?
“Deployment issues (placement,
power, environmental) – slow
deployment
• Multiple landlords
• Different types of sites
• Zoning / permitting issues
Backhaul
• Line of sight
• Non-line of sight
• Wireline
• Wireless Informa Telecoms & Media Small Cells
Market Status Report June 2012
SITE ACQUISITION AND BACKHAUL ARE THE BIGGEST HURDLES
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Backhaul options
Mounting options indoor, outdoor
Various characteristics (3G/LTE)
METROCELL DEPLOYMENT OPTIONS
On a façade On a pole Lamppost
Integrated MicroWave
From 250mW to 5W
Beamsteering options
Fiber Copper
Distributed or all in one
Integrated Wi-Fi
Indoor
WiFi
NUMEROUS COMBINATIONS BEING EXPLORED FOR DEPLOYMENT
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SMALL CELL BACKHAUL REQUIREMENTS
BACKHAUL REQUIREMENTS
COMPARED TO MACRO CELLS
COMMENTS
Capacity Lower mean capacity, similar peak
Small cells generate less backhaul traffic than multi-cell/mode/band macro cells, but it is much burstier Metrocell: 5-50 Mbps expected (typically 10 Mbps for WCDMA small cell)
Scalability More scalable Faster growth, rapid deployment, needs shorter lead time on new connections
Latency More delay tolerant for some architectures
WCDMA Iuh based small cells = lower delay requirements
Availability Less 99 % to 99.995 % for small cells. Macro network fallback in capacity deployments
Size and Weight of equipment
Smaller and lighter at small cell end
Compact backhaul is essential
Installation & commissioning
Faster, simpler Small cells are close to plug and play Backhaul should also move in this direction
REQUIREMENTS ARE LESS STRINGENT BUT COSTS ARE IMPORTANT DUE TO SCALING
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SMALL CELL BACKHAUL OPTIONS RIGHT MIX OF TECHNOLOGY, FOR RIGHT SITUATION, FOR RIGHT TCO
METRO CELL ACCESS
TECHNOLOGY
POTENTIAL CAPACITY
TYPICAL APPLICATION
MILLIMETER WAVE (LOS P2P)
~1000 Mb/s • All Sites (End sites or hub) • High-capacity, low latency, short
hops
SUB-6 GHz (PROPRIETARY OR
802.11 BASED) ~200 Mb/s
• End site application • Single Hop
GPON 2.5 Gb/s • Leverage fiber infrastructure
VDSL w/ BONDING ~300 Mb/s • Leverage copper deployment
ETHERNET (SERVICE)
/FIBRE
10 Gb/s • High capacity, strong QoS
requirements • Self-build or leased
Router
LOS
NLOS
GPON SFP ONT
WIRELESS AND WIRELINE TECHNOLOGIES BRING DIFFERENT TECHNICAL CAPABILITIES
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KEY DEPLOYMENT COST DRIVERS
Items Cost Drivers Mitigators
Site Acquisition Individual negotiations Expensive bureaucracies
Negotiate in bulk with best partners
Site Survey Expensive on-site surveys Use remote/destktop surveys
Installation Heavy NE with multiple components => extra labor, special equipment
Lightweight Metrocells with integrated units, no special equipment
Commissioning Extensive manual configuration Self configuration + SON = plug ‘n play
Integration Extensive manual configuration Self configuration = plug ‘n play
Optimization Extensive manual configuration Several walk/drive test cycles
Self configuration + SON = plug ‘n play
Acceptance
Testing
Manual steps => higher fallout Self configuration + SON = high acceptance ratio
Backhaul
Installation
Remote backhaul requires expensive trenching
Leverage wireline infrastructure and wireless backhaul
Power
Installation
Remote power requires expensive trenching
Use common trenching as backhaul or use local power
INNOVATIVE DEPLOYMENT STRATEGIES AND EQUIPMENT FEATURES REDUCE COSTS.
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DEPLOYING SMALL CELLS TOTAL COST OF OWNERSHIP
Design Nominal Design Constructive Design ….
Site Acquisition Legal fees Permits Other “closing costs” ……
Backhaul Installation Civil works: Horizontal run Civil works: Vertical run Equipment installation Connection and
configuration ……
Power Installation Civil works: Horizontal run Civil works: Vertical run Equipment installation Connection and configuration ….
Metrocell Installation Mounting Cabling. …
Integration with servers/NEs Integration with SeGW Integration with other servers Integration with core NEs …
RF Performance Optimization Drive/walk testing Data collection RF Performance Analysis …
Acceptance Testing/Turnup Quality assessment Certification/Rework ….
Site Survey Power/backhaul availability Hardware requirements …
Commisioning Provisioning Testing …
OPEX Site Rental & Power Backhaul Operations
Numerous factors affect the cost of deployment and need to be analyzed.
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EXAMPLE OUTDOOR DESIGN RESULT
EQUIPMENT, BACKHAUL AND SITE COSTS OFTEN DOMINATE OTHER ITEMS
Small cell, and backhaul accounting for 70%+ of
deployment cost
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Backhaul Device
LAN switch
LAN switch
Metrocell
• Cost Elements:
Equipment
Metrocell
LAN Switches
Cat5 cabling
Deployment tasks
Site Survey, RF Design, etc.
• Cost Drivers:
Building configuration
Size of coverage areas
Wall material
Amount of open/closed space
INDOOR DEPLOYMENT COST DRIVERS
INDOOR DEPLOYMENT COSTS DRIVEN BY BUILDING CONFIGURATION
Typical largest cost items:
Equipment CAPEX, RF Design, BH Connection
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EXAMPLE NETWORK EVOLUTION WITH AND WITHOUT METRO CELLS
Site Requirement
793
343 (221)
3,005 (1876)
-
500
1,000
1,500
2,000
2,500
3,000
3,500
Nu
mb
er
Of
Sit
es R
eq
uir
ed
Macro Only Macro and Metro
343
3005
• SOME MACRO ADD IS UNAVOIDABLE, BUT THE NUMBER IS MUCH LESS WITH HETNET
• SMALL COSTS NEED TO BE >10X SMALLER THAN MACRO COSTS
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• Small cells are essential tools for handling mobile data
explosion efficiently
• Capacity, coverage and performance are all benefits of small
cells
• Targeted deployment in traffic hotspots is essential for
maximum benefits
• Minimizing deployment costs is key to efficient deployment
of small cells
SUMMARY LEARNINGS