PACKET MICROWAVE FOR METRO CELL BACKHAUL ENABLING A SEAMLESS EVOLUTION TO HETEROGENEOUS NETWORKSAPPLICATION NOTE

TABLE OF CONTENTS

Introduction / 1

Backhaul challenges for metro cells / 2

Getting wireless backhaul to the metro cell / 2

Scaling the macro cell microwave network / 4

Rapidly deploying metro cells / 4

The Alcatel-Lucent Packet Microwave Mobile Backhaul Solution / 4

Metro cell backhaul flexibility through 9500 MPR-s / 5

Microwave network scale / 6

Professional services for rapid metro cell deployment / 7

Conclusion / 8

References / 8

Acronyms / 8

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

1

The transition to higher capacity 3G and 4G/LTE networks and

the introduction of small cells are the strategic tools that mobile

network operators (MNOs) have at their disposal to keep pace with

rapidly increasing mobile service demand. Small cells introduce

new backhaul challenges because their optimal placement means

that they will be deployed on street furniture, inside heavily

populated buildings and on the sides of buildings. Leveraging

existing macro cell sites to reach these small cell locations is an

attractive approach to solve the challenges associated with small

cell backhaul. This approach will introduce macro cell backhaul

scaling challenges, including the scaling of bandwidth supported

over scarce microwave spectrum that backhauls the majority of

macro cells today. The Alcatel-Lucent Packet Microwave Mobile

Backhaul solution addresses these challenges and allows for an

efficient transition to heterogeneous networks.

INTRODUCTIONThe transition to higher capacity 3G and 4G/LTE networks and the introduction of small cells are the strategic tools that mobile network operators (MNOs) have at their disposal to keep up with rapidly increasing mobile service demand. Small cells enable the delivery of capacity and coverage exactly where needed to relieve overloaded macro cell networks and deliver an enhanced Quality of Experience (QoE) to mobile subscribers. However, optimal placement of small cells means deployment on street furniture, inside heavily populated buildings and on the sides of buildings. These types of deployments introduce new backhaul challenges that must be overcome for the successful deployments of small cells and the heterogeneous networks they support.

Metro cells are a subset of small cells that include MNO-managed small cells but exclude residential and enterprise femto cells. To scale mobile service capacity, it is estimated that three to ten outdoor metro cells will be used per macro cell.

One widely anticipated approach for metro cell backhaul is to use metro cell optimized wireless devices to carry traffic to the nearest macro cell tower. ABIresearch® expects that these types of wireless devices will be used to backhaul over 50 % of metro cell sites. [1] This type of deployment introduces backhaul challenges in the following areas:

• Selectingtherightwirelessmetrocellbackhaultechnology

• Scalingmacrocellbackhaulnetworkbandwidth

• Attainingtheskillsneededtosuccessfullydesignanddeployend-to-endmetrocellbackhaul networks

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

2

Microwave technology is used to backhaul traffic for more than half of the macro cell sites worldwide. The reasons for this prominence are well known: in many cases micro-wave allows for faster and more cost-effective deployment of backhaul capacity than do wireline alternatives. Ethernet packet-based microwave connections are increasingly replacing legacy PDH E1/T1 and SDH/SONET microwave connections. According to Heavy Reading, packet-based backhaul is expected to be deployed for greater than 80 % of all backhaul connections by 2015. [2] Metro cells are designed for packet-based back-haul, and their introduction will further accelerate an evolution to packet microwave.

This paper reviews extensions to the successful Alcatel-Lucent Packet Microwave Mobile Backhaul solution that address the backhaul challenges for metro cells.

BACKHAUL CHALLENGES FOR METRO CELLSSelecting an optimal site for metro cell deployment is a tradeoff among Radio Access Network (RAN) performance, site leasing costs and backhaul availability. Extending backhaul to metro cell sites from MNO established macro cell towers is an attractive backhaul option because it leverages established macro cell sites and associated costs. Running fiber between metro cell and macro cell locations is often prohibitively expen-sive, so has led to the introduction of metro cell optimized wireless backhaul devices. However, deploying these types of devices comes with a specific set of challenges:

• Selectingtheoptimalwirelesstechnology

• Scalingthemacrocellbackhaulnetwork,includingmicrowavelinks,tohandleincreased metro cell packet demands

• Acquiringthebackhaulskillsandresourcestorapidlyandcost-effectivelydeploymetro cells

Getting wireless backhaul to the metro cellTo deliver mobile subscriber capacity where it is needed, metro cell sites need to take advantage of street furniture such as lamp posts and the sides of buildings. Metro cell deployment numbers and their locations, together with the number of subscribers they support, make metro cell deployments different from macro cell deployments in the following ways.

Environmental differences

• Tobeoptimallylocated,ametrocellsiteneedstobevisuallyunobtrusivetoavoidrejection from the public.

• Themetrocellsitecan’talwaysbeplacedinaprotectedindoorenvironment,sometrocellbackhaulequipmentmustbeabletowithstandaharshoutdoorenvironment.

• Optimalmetrocellplacementoftenprecludesline-of-sight(LOS)linkengineeringbetweenthe metro cell and the macro cell locations. Non-line-of-sight (NLOS) technologies are also requiredtogetaroundLOSobstaclessuchastreesandbuildingstructures.

Cost-of-deployment differences

• AmetrocellsitemustbesetupwithminimalOPEX,itshouldbeabletobeconstructedbyasinglepersonwithonevisittothecellsite,anditcan’trequirepreciseantenna alignment schemes to support backhaul.

• Frequencylicensingfeesandtherelatedinterferencestudiesshouldbeminimized.

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

3

These differences have provided the impetus for new generation of small form factor wirelesssystemsusingfrequencybandsthatfalloutsidethelicensedfrequenciestypi-callyusedformacrocellbackhaul.Ofthesefrequencybands,twoareemergingwiththestrongestpotentialtosupportmetrocellbackhaulrequirementsforavailabilityandperformance.

60-GHz frequency bandTheadvantagesofthe60-GHzfrequencybandare:highcapacity,lowlatency,well-understood LOS link engineering, high immunity to interference, and license-free operation.

Link transmission rates as high as 1 Gb/s, with sub-50 microsecond latency can be implemented using this band. These latency characteristics are consistent with macro cell microwavebackhaulfrequenciesthatareusedtoday,andtheyenablethe60-GHzbandtoaddress the most demanding 2G, 3G and/or 4G/LTE backhaul Service Level Agreements (SLAs). The high capacity that this band offers allows it to be positioned for end metro cell sites and the aggregation of several metro cell sites using various network topologies.

This band also presents a very narrow beam, making it easier to mitigate interference in an unlicensed domain. Potential interference can only occur with another 60-GHz channelifitistightlysqueezedintothesamenarrowsector.Thehighoxygenabsorp-tion characteristics of this band limit maximum link distance to 1 km, allowing several 60-GHz links to be densely packed into a small area without interference issues. These characteristics enable maximum network bandwidth using low-cost unlicensed bands.

Unlicensed band operation also avoids licensing delays and associated costs, making it fastertodeployandlessexpensivetooperatethanlicensedfrequencies.

This band is widely available in many countries:

• UnitedStates,CanadaandBrazil(57-64GHz)

• Europe(59-66GHz)

• SouthAfrica,AustraliaandChina(59-64GHz)

• Japan(59-66GHz)

• NewZealandandKorea(57-64GHz)

Sub-6 GHz frequency bandThesub-6GHzfrequencybandsupportslicensedandunlicensedNLOSoperationto address deployments where obstacles to LOS technologies exist. This band has thecharacteristicsrequiredtooperateinthehighinterferenceandseveremultipathconditions typically encountered with metro cell dense urban deployments. However, implementations that leverage this band typically introduce additional delay and delay variation when compared to pure LOS technologies.

Toavoidadditionaldelayanddelayvariation,carefulengineeringistypicallyrequiredto meet backhaul SLAs. Bandwidth capacities supported by implementations using this bandtypicallyrequiredeploymentatendmetrocellsitesratherthantheaggregationofmany metro cell sites.

Sub-6 GHz implementations typically support point-to-point and point-to-multipoint configurations. Point-to-multipoint implementations leverage a common hub site antenna to communicate with individual spoke endpoints to provide cost savings over deploying multiple point-to-point links.

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

4

Scaling the macro cell microwave networkThe introduction of metro cells will accelerate scaling pressures on macro cell microwave backhaul networks. This pressure will lead to the development of increased higher order modulation schemes and regulatory bodies allowing for wider microwave channels to supporthigherbandwidthcapacities(suchastherecentFCCrulingsallowingwiderchannels in the 6-GHz and 11-GHz bands). While these initiatives help to scale micro-wave bandwidth, they are insufficient on their own to increase microwave link capacity totherequiredlevels.

It is becoming increasing difficult to realize backhaul payload capacity gains when moving to higher order modulation rates due to degraded link performance and/or related antenna costs. Support for wider microwave channel width can also adversely impact microwaveperformanceandincreasedeploymentcosts.Acquiringadjacentchannelstocreate wider channels may also be difficult or impossible in congested urban areas where muchoftheincreasedcapacityisrequired.

So, while support for higher order modulation and wider channels can help address increasing bandwidth demands on microwave links, they are not without issues, and areinsufficientontheirowntoincreasemicrowavelinkcapacitytotherequiredlevels. Abroaderapproachisrequiredtothoroughlyscalescarcemicrowavespectrum— anapproachthatleveragesmicrowavechannelbondingtechniques,including:

• Thebondingofchannelswithdifferentpolarizationsatthesamefrequency

• Datatrafficcompression

• Optimalmultiplexingofbackhaultrafficwithadaptivemodulation-aware Quality of Service (QoS) mechanisms

• Advancedpacketnetworking

Rapidly deploying metro cellsMNOs and backhaul transport providers (BTPs) realize they need to evolve their net-works to packet-based backhaul to support the addition of metro cells to the macro cell network and simplify the operation of their networks. However, these operators may not have the expertise or resources to support this transition in the deployment timeframes required.Packetbackhaulexpertiseandsupportingtoolsarerequiredtodeterminetheright backhaul approach to be used and are critical to the design of a reliable, evolvable and robust end-to-end backhaul network.

THE ALCATEL-LUCENT PACKET MICROWAVE MOBILE BACKHAUL SOLUTIONAs part of the Alcatel-Lucent Packet Microwave Mobile Backhaul Solution, the Alcatel-Lucent9500MicrowavePacketRadio(MPR)hasquicklyestablishedapacketmicrowave leadership position by supporting features that enable:

• 2G,3Gand4G/LTEbackhauloveracommonpacketnetwork

• Superiorspectrumperformance

• Service-awareQoS

• Synchronizationdistributionflexibility.

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

5

TheAlcatel-LucentPacketMicrowaveMobileBackhaulsolution(seeFigure1)hasprovided a 4G/LTE mobile backhaul transformation capability for MNOs and BTPs globally, andhasbeenextendedwiththemetrocellbackhaulflexibility,scalabilityandrapidtime-to-deploycapabilitiesrequiredtosupportthebackhaulofheterogeneousnetworksconsisting of metro cells and macro cells.

Metro cell backhaul flexibility through 9500 MPR-s Rapidly deploying cost-effective backhaul to optimal metro cell locations is critical to maximizing RAN performance and addressing mobile subscriber QoE. Alcatel-Lucent hasenhancedits9500MPRportfoliodeploymentflexibilitywiththefollowingmetro cell backhaul options:

• Sub-6GHzNLOSlicensedandunlicensedoptionsthatcansupportupto200Mb/s net aggregate throughput in point-to-point or point-to-multipoint configurations

• 60-GHzunlicensedLOSoptionsthatcansupportfull-duplexgigabitcapacitiesforaggregating several metro cells

These9500MPR-sruggedsmallformfactoroptionsmaximizespectrumperformanceand are powered using Power over Ethernet (PoE) technology. At metro cell sites they aredirectlyconnectedthroughEthernettometrocellsorrelatedbackhaulequipment.AtmacrocellsitestheyareconnectedthroughEthernetto9500MPRdevicestosupportsubtending backhaul from macro cell sites to metro cell sites.

Figure 1. Alcatel-Lucent Packet Microwave Mobile Backhaul solution

Metro cell sites (9500 MPR-s)

Macro cell tail site (9500 MPR)

Mobilecontrollers/gateways

Metro aggregation/transport

Microwavehub site

9500 MPRSub-6 GHz

P2MP

Sub-6 GHzNLOS

60 GHz

5.8 GHz6-42 GHz

60 GHz80 GHz

5.8 GHz6-42 GHz

60 GHz80 GHz

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

6

The9500MPRmanagementplatformsenablerapidprovisioningofend-to-endbackhaulservices,includingover9500MPR-slinks,eliminatingtheneedtoindividuallyconfigureeach device in the service path. This reduces the complexity and risk associated with provisioningcomplexservicesandprovidessupportforFault,Configuration,Accounting,PerformanceandSecurity(FCAPS)management.

With these metro cell backhaul focused additions, Alcatel-Lucent continues to offer the most comprehensive end-to-end portfolio for microwave-based mobile backhaul.

Microwave network scaleToaddressincreasing3Gand4G/LTEmacrocellbandwidthcapacityrequirements,operators globally are evolving their traditional microwave networks to packet micro-wave networks. The addition of metro cells to the macro cell network will further acceleratetheevolutiontopacketmicrowavenetworksandrequirethemtoconstantlyscale to address increasing metro cell backhaul demands.

As previously mentioned, initiatives in the areas of increased higher order modulation and the widening microwave channels will help scale microwave to meet capacity demands.However,theseinitiativesareinsufficientontheirowntomeettherequireddemand.The9500MPRgoesbeyondtheseinitiativestodelivertherequiredscalabilitywith support for the following features:

• Intelligent packet compression: Algorithms that can increase microwave bandwidth utilization by as much as 300 %

• High capacity microwave channel bonding: The ability to seamlessly bond radio channels into higher capacity microwave connections, including support for bonding channelswithdifferentpolarizationsatthesamefrequency

• Advanced packet networking:

¬ Multiservice-aggregation support allows 2G, 3G and 4G/LTE to share a common packet-based backhaul without having to strand bandwidth between TDM and packetdomains—acommonissueassociatedwithhybridmicrowavesystems

¬ High-capacity microwave topology support with up to 24 microwave connections at dense microwave hub sites, including the ability to bond up to 4 radio channels in each of these directions, utilizing a compact 2-RU, power-efficient, indoor Microwave Services Switch (MSS)

¬ Standards-based ITU G.8032v2Ethernet networking options that allow for maximum network bandwidth utilization and offer sub-50 millisecond network reliability capabilities to protect against network failures

• Service-aware QoS: Optimal scheduling of packet traffic to stay within SLA bounds for backhaul delay, delay variation and loss

• High performance adaptive modulation capabilities that maximize the use of high-order modulation when adjusting to changing radio propagation conditions

• Patented synchronization algorithms based on radio symbol rate: Algorithms that do not consume precious over-the-air bandwidth and are also totally independent of network load. These algorithms complement end-to-end synchronization distribution options based on:

¬ Synchronous Ethernet (SyncE)

¬ IEEE 1588v2 Precision Time Protocol

¬ SONET/SDH

Packet Microwave for Metro Cell Backhaul ALCATEL-LUCENT APPLICATION NOTE

7

Afullrangeofmacrocellbackhaulfrequencyoptionsfrom6GHzto80GHzarealsoavailable to scale network capacity. To further maximize spectrum options for macro cellbackhaul,the9500MPRsupportscarriergrade5.8-GHzunlicensedoperation.Thisunique5.8-GHzoptionissupportedonacompacttransceiverthatcanuniversallyaddress any microwave deployment. It enables rapid macro cell site deployment with the abilitytoseamlesslytransitiontolicensedbandoperationiforwhenrequired.

Figure2showstheAlcatel-Lucent9500MPRportfolio.

Professional services for rapid metro cell deploymentThe9500MPRmetrocellandmacrocellbackhaulsolutionsaresupportedby Alcatel-Lucent’sprofessionalservices.Designandbusinesscaseanalysistoolsthat leverage proven Bell Labs network modeling algorithms are used to support the following backhaul professional services:

• Businesscaseanalysistodeterminetherightbackhaulapproach

• Designservicesthatensurereliable,evolvableandrobustbackhaul

Theseprofessionalservicescanbeusedtoinstantlygaintheskillsrequiredtosuccessfullydesign and rapidly deploy packet backhaul for metro cells and heterogeneous networks.

Figure 2. Alcatel-Lucent 9500 MPR portfolio: Enabling a seamless evolution to heterogeneous networks

9500 MPR

MACRO CELL BACKHAUL

Outdoor

Common MPTtransceiver for fulloutdoor and split-mount

COMPACT INDOOR OPTIONS

9500 MPR

MSS-4 (1 RU)

MSS-8 (2 RU)

MSS-1 (0.5 RU)

9500 MPR-S

METRO CELL BACKHAUL

Outdoor

60 GHz Sub 6 GHz

18 cm7 in

27 cm10.6 in

CELL SITE DEPLOYMENT FLEXIBILITY

NETWORKSCALABILITY

RAPIDLYDEPLOY

www.alcatel-lucent.com Alcatel, Lucent, Alcatel-Lucent and the Alcatel-Lucent logo are trademarks of Alcatel-Lucent. All other trademarks are the property of their respective owners. The information presented is subject to change without notice. Alcatel-Lucent assumes no responsibility for inaccuracies contained herein. Copyright © 2013 Alcatel-Lucent. All rights reserved. M2012125516 (February)

CONCLUSIONThe transition to higher capacity 3G and 4G/LTE networks and the introduction of metro cells are the strategic tools that MNOs have at their disposal to keep pace with rapidly increasing mobile service demand. Metro cells introduce new backhaul challenges because their optimal placement means they will be deployed on street furniture, inside heavily populated buildings and on the sides of buildings.

Leveraging existing macro cell sites to reach these metro cell locations using metro cell optimized wireless technologies is an attractive approach to solve the challenges associated with metro cell backhaul. This approach will introduce macro cell backhaul scaling challenges, including the scaling of bandwidth supported over scarce microwave spectrum that backhauls the majority of macro cells today.

Justasthe9500MPRhasenabledtheoptimaldeploymentoflargemacrocellnetworks,newproductextensionsdeliverthemetrocellsitedeploymentflexibility,microwavenetwork scalability and rapid deployment support to allow for an efficient transition to heterogeneous networks.

REFERENCES[1]ABIresearch,BackhaulOptionsforOutdoorSmallCells.NickMarshall,Principal

Analyst,MobileNetworksandAdityaKaul,PracticeDirector,MobileNetworks:September 10, 2012.

[2]HeavyReading,EthernetBackhaulQuarterlyMarketTracker:January2013.

ACRONYMS2G Second-Generation Mobile Network

3G Third-Generation Mobile Network

4G Fourth-Generation Mobile Network

BTPs backhaul transport providers

FCAPS Fault, Configuration, Accounting,

Performance and Security

IEEE Institute of Electrical and Electronics

Engineers

ITU International Telecommunication Union

LOS line-of-sight

LTE Long Term Evolution

MNO mobile network operator

MPR Microwave Packet Radio

MSS Microwave Services Switch

NLOS non-line-of-sight

OPEX operating expenditures

PDH Plesiochronous Digital Hierarchy

PoE Power over Ethernet

RAN Radio Access Network

RU Rack Unit

SDH Synchronous Digital Hierarchy

SLA Service Level Agreement

SONET Synchronous Optical Network

SyncE Synchronous Ethernet

TDM Time Division Multiplexing

QoE Quality-of-Experience