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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

COPYRIGHT © 2013 ALCATEL-LUCENT. ALL RIGHTS RESERVED. 6

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


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


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


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


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?


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


CORNERSTONES OF METRO DEPLOYMENT

1

2

3

4

5

6

7

8

10

11

12

13

14

15

16

9

17 200m

PN

-99.2250 -99.2167 -99.2083 -99.2000 -99.1917 -99.1833

19.4

167

19.4

250

19.4

333

19.4

417

-99.2250 -99.2167 -99.2083 -99.2000 -99.1917 -99.1833

19.4

167

19.4

250

19.4

333

19.4

417

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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COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED. ALCATEL-LUCENT — INTERNAL PROPRIETARY — USE PURSUANT TO COMPANY INSTRUCTION

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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COPYRIGHT © 2011 ALCATEL-LUCENT. ALL RIGHTS RESERVED. ALCATEL-LUCENT — INTERNAL PROPRIETARY — USE PURSUANT TO COMPANY INSTRUCTION

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

small cells big impacts: performance · pdf fileimprove retainability and accessibility ......

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