The Importance of Testing Long Term Evolution (LTE)

7/31/2019 The Importance of Testing Long Term Evolution (LTE)

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White Paper

WEBSITE:www.jdsu.com/test

The Importance o Testing Long Term Evolution (LTE)

in Public-Saety Networks

In emergencies, it is imperative that government agencies can communicate internally, that emergencyprofessionals have secure and uninterrupted communications, and that the population is keptinformedneeds that demand a reliable and robust network.

The U.S. has a sophisticated, if aging, emergency-communications network that reliably delivers publicsafety information, and it has served us well. However, it is outdated and is designed only for voicecommunications. Today, the ever-growing sophistication of network components, devices (smartphonesand tablets), and ways in which we communicate (video, e-mail, social sites) have in turn created moresophisticated communications methods for emergency services. To take advantage of these methods, thenetwork must be upgraded.

The National Institute of Standards and Technology (NIST) is the first federal agency to researchguidelines for telecommunications and information technology standards for interoperability andinformation sharing among public safety agencies. NIST, through its Public Safety CommunicationsResearch (PSCR) program, is building a 700 MHz public-safety broadband trial network to givemanufacturers and first responders a location to deploy and test their systems in a multivendor, neutralhost environment. The goal is to demonstrate and evaluate the behaviors of 3GPP/LTE technologydeployed in the 700 MHz bands, specifically to meet the needs of public-safety agencies.

LTE is a new, all-IP, high-bandwidth, wireless technology that enables the delivery of new, advancedservices in a guaranteed, secure and reliable way. The U.S. government has already licensed the 700 MHzfrequency range for the access network for LTE and the new Public-Emergency System will use band 14within this range.

This paper is organized in four sections:

BenefitsofanLTE-basednetwork

Whatneedstobedone?

Whathappensafterdeployment?

Lessonslearned


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2White Paper: The Importance o Testing Long Term Evolution (LTE) in Public-Saety Networks

Benefits of an LTE-based networkHigh bandwidth LTE enables new, advanced services that will significantly improve emergencycommunications with improved capabilities for:

Real-time video

Face scanning and recognition for quick verification against centralized facial recognitiondatabases from any location

Video surveillance of areas not served with a fixed connection (for example, coastal areas anddeserts) resulting in better security

Instant visual emergency assessments

E-mail

Fast and reliable delivery

Recordedcommunications

Database interrogation

Fast access to suspect information from anywhere

Fast retrieval of information needed during an emergency

Voice

Higher-quality transmissions and transcriptions

These new services will be delivered via a single, integrated, all-IP network that will better inform

emergency service providers, letting them make better decisions faster.

What needs to be done?

WorkonthisnewnetworkhasalreadybegunandJDSUhasbeencloselyinvolvedwithNISTintestingitscapabilities to prove that LTE can deliver these services, particularly in emergency situations, when networkswill be stressed to their limit. Part of this work is validating and testing LTE-enabled equipment with a view tocreating standards needed for a national, next-generation public-safety network.

JDSUproductssupportboththeAltairchipsetandtheIPWirelessBand14UE(http://www.ipwireless.com/government/products/devices) earmarked for public safety and being used by NIST in several of the firstwaiverholdersnetworkrollouts.JDSUisakeycontributortotheMulti-ServiceForum(www.msforum.org)

and has contributed heavily to the VoLTE Interoperability Event 2011 and whitepaper (http://www.msforum.org/interoperability/MSF_VoLTE%20_2011_WhitePaper.pdf).

There are three key areas where testing will help establish a reliable and conformant network:

Basicfunctionalitytestingdoesitwork?

Comprehensivesystemandnode-leveltestingdoesitworkefficiently?

Inter-operabilitytestingdoesitworkeverywhere?


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Basic functionality testingdoes it work?To determine if LTE equipment submitted for use in the trial project has been configured correctly to achievedesired functionality, it is necessary to validate the RF environment to ensure cells are deployed in the opti-mal locations and that they are optimized for most efficient operation. Figure 1 shows a typical scenario usingJDSUDriveTest,whichinconjunctionwithAltairchipsetsandanIPWirelessBand14device,validatestheRF performance of the proposed network. Emergency services will need guaranteed communications, bothoutdoorandindoor.TheJDSUDriveTestsolutioncanbeusedinavehicleorbackpack,enablingvalidationofRF coverage and service capability within complex buildings (malls, airports, skyscrapers, stadiums). Typicaltests will include:

RFlayerteststoensurethatthedeployedequipmentwillnotinterferewithotherexisting700MHzLMR,PSCR systems

Servicecoveragevalidation

Outdoorandindoorscenarios

Handoververification

Messaging/protocoltests

Public-safetyapplicationtests(video,data)

Performancetests(throughput,latencyetc)

(b) Indoor Use Model (In Building)

Laptop PC and Phone/Receiver equipment

in backpack or JDSU FTA Phone

(a) Outdoor Use Model

Attended Drive Test with laptop PC and Phone/

Receiver equipment in moving vehicle

Corrective

Actions Optimization

Process

Drive Testing

(Outdoor/Indoor)

Post Processing

Data Analysis

Customer/Network

Trouble ticket,

Initial Planning,

Optimisation

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3

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Figure 1. RF perormance validation


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KPIs & Analytics with DM TReal-Time Protocol Analysis Historic Analysis

with Call Manager

Multi-User Architecture

Centralized configuration and s/w management

Serving Network SS7, Services, IMS, IN

Internet

2G/3G/LTE RAN

UEs

Uu

Comprehensive system and node-level testingdoes it work efficiently?Typically, this area of testing requires complex protocol scenarios to validate that the performance of the corenetwork is able to meet the demand placed on it during emergency situations. Ideally, a testing solution allowsmany engineers to share the same hardware without impacting other tests, making the process efficient, con-sistent, and reliable.

Figure2belowshowsthetypicalconfigurationofaJDSUSignalingAnalyzerRealTime(SART)deployedinalab which can be used to test all the areas described below. Its multi-user architecture lets large numbers of engi-neers perform testing simultaneously. Capabilities include:

In-depthandadvancedperformancetesting

Multiuser,loaded-networkstresstesting

Networkarchitecturetypetesting

Interoperabilitytestingthatincludestestingtheevolvedpacketcore(EPC)andinter-connecting,mul-tiple EPCs

eNodeB-eNodeBhandovers

Mobilitymanagemententity(MME)-MMEhandovers

LTE-to-LTEhandovertestingandevaluation

Figure 2. Service verifcation and services quality testing


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Control and user plane traffic will be significantly higher in emergency situations due to the volume of calls.In addition, LTE introduces a significant increase in the number of messages required to set up, maintain, andtear down a session compared to previous technologies. It is, therefore, imperative that all sessions can be cap-turedandanalyzedinasimplewaythatexpeditesnetworkdeploymentandtroubleshooting.JDSUisuniquein correlating the LTE signaling generated by UEs connected to its Drive Test solution and correlating it withtheprotocolcapturedinthenetworkbySART.Thisenablesamuchgreaterinsightintoproblems.Figure3showsatypicalscenariowheretheJDSUSARTsolutionenableshigher-qualitytesting.

Figure 3. Load and stress testing


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EPC

eNodeB

Vendor A

S1-MME

X2

EPC

Vendor B

X2

Uu

EPC

Vendor A

eNodeB

Vendor A

S1-u

S1-MME

S1-u

S1-MME

S1-u

S1-MME

S1-u

Uu

IOT S1Validate single vendor eNodeB

with EPC from different vendor

IOT X2Validate eNodeB from

different vendors

eNodeB

Vendor A

eNodeB

Vendor B

EPC

Inter-operability testingdoes it work everywhere?New networks are expensive and deploying LTE will be no different; however, unlike previous technologieswhereallthenetworkelementsorcomponentsofthenetwork(RAN,CORE)wouldtypicallybesuppliedbyasingle vendor, the LTE standards body has insisted on interoperability. This requires all LTE network elementsto work with each other irrespective of vendor. This is a crucial step in providing a more competitive environ-ment for network operators as they will no longer be tied to a single vendors pricing model. Figure 4 shows atypicalscenarioforthisinteroperationwhereaconfirmationneedstobemadethateNodeBsfromdifferentvendors interoperate and work with an EPC from another vendor.

Figure 4. Multi-vendor interoperability

Inadditiontoensuringthatnetworkelementsareinteroperable,itisalsocrucialtoconfirmthatAltairchipsetsandtheIPWirelessUEswhichwillbeusedbytheemergencyservicesalsoworkonanycombinationofvendornetwork elements. This flexibility of interoperation available in LTE networks presents significant challengesparticularly in the areas of testing, where it is now even more important to be able to test and confirm thatequipmentfromdifferentvendorscancoexist.TheJDSUSARTsolutionletsengineersindependentlycheckthat the operation of one vendors equipment is exactly the same as another vendorsrather than simplyassuming it is so.


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In addition to the interoperability of multiple vendors equipment, it is essential that handovers between theeNodeBsandhandoversbetweenmultipleMMEscanbetested.Figure5showsahigh-levelnetworksche -matic for LTE where the S10 interface is the link that interconnects multiple MMEs which will be located inmultiplelocations.Handovers,whetherbetweeneNodeBsonthesameMME,orbetweeneNodeBsondiffer-entMMEs,presentspecifictestchallenges,whichareaddressedbybothJDSUDriveTestandSARTsolutions.

Losingserviceisnotacceptableinanemergencysystemduringacrisis.Thesystemneedstowork24/7/365without exception, and therefore must be tested thoroughly.

Gn/GpSG SN

MMES1-MME

UE SGW PGW

Gr

Gn

Gn

Gx

Rx

= User Plane

= Control Plane

S5

SGi

S6a

S10 S11

U TRAN

GERAN

2G/3G/Common

LTE/EPC

Operators IP

Services

(IMS, PSS, etc.)

E-UTRAN

S1u

HSS

PCRF

Figure 5. High-level LTE network view

What happens after deployment?

Wehavediscussedhowtotestthenetworkduringdevelopmentpriortodeployment.Oncethenetworkisdeployed it must be operated, managed, and maintained. RF performance and service accessibility must becontinually validated using Drive Test, both outdoors and indoors, to ensure that emergency services canalways access the network.

Problems will always occur and the challenge is to minimize their impact by testing early in the lab as describedabove, as well as continually monitoring during operation to identify problems before they impact users. How-ever,asperfectasplansmaybe,problemswillstilloccurinthedeployednetworkandtheJDSUDriveTestandSARTsolutionscanbeusedtoidentifytheseproblems.JDSUalsohasanassurancesolutionthatcanbedeployed on the entire network, enabling alarming and troubleshooting of network and service problemsbefore users become aware.


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Productspecicationsanddescriptionsinthisdocumentsubjecttochangewithoutnotice.2012JDSUniphaseCorporation301730850000112LTE.WP.NSD.TM.AE January2012

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White Paper: The Importance o Testing Long Term Evolution (LTE) in Public-Saety Networks

ConclusionWithoutrigoroustestingofthewholenetworkRF,access,andcoreyoucannothaveconfidencethatitwillwork when it is most needed during emergencies when loading will be at its highest. In addition to experiencewithNIST,JDSUhasconsiderableLTEexpertise,helpingdeliverLTEnetworktestingsolutionstoTDC,theleading provider of communications solutions in Denmark , and CSL, Hong Kongs first and leading mobile net-workoperator.JDSUalsoprovidespracticaladviceonwhatisrequiredtogetanLTEnetworkupandrunning.This combination of experience, solutions, and consulting are key components required when delivering anynewnetwork,notjustLTE.JDSUisuniquelypositionedtoensureefficientdeploymentswithsolutionscovering:

Drivetest

OptimizingandtroubleshootingFDD-LTEandTD-LTEnetworks

Supporting UE device measurements and multi-band, multi-technology receivers

Maximizing efficiency in the detection and isolation of problems

Reducing the cost of ownership through a single test platform

Protocolanalysis

End-to-end analysis and troubleshooting for LTE lab networks

Comprehensive monitoring and network diagnostics by interpreting, correlating and analyzing pro-tocol signaling messages produced by multiple network technologies at mobile network interfaces

Real-time performance analysis and measurements against key performance indicators (KPIs)

Intelligent hardware probes

Multiuser access ArobustAPItoenableworkflowautomation,speedingdeploymentsandreducingtime-to-revenue

and operating costs

Customerexperiencemanagement

End-to-end analysis and troubleshooting for live LTE networks

Analyticstovalidateperformance

QoS analysis including KPIs

LTE QoS class identifiers

Asoneoftheworldslargestcommunicationstestequipmentcompanies,JDSUistheonlyvendorwhohaswon

an independent award for our LTE solutions and that has a portfolio of solutions addressing all of the compo-nentsthatarerequiredtobetestedinanetwork.Ourheritage,people,knowledge,experience,andethicsmakeus the ideal partner to ensure successful deployment of emergency systems for public safety.

For more information, please contact Steve Laabs ([email protected]).

The Importance of Testing Long Term Evolution (LTE)

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