071 enterprise small cell networks

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www.scf.io/ www.smallcellforum.org

DOCUMENT

E-SCNUse cases and requirements

December 2013

071.06.01

SMALL CELL FORUM

RELEASE 6.0

Solving the HetNet puzzle

1 7 : 2 5

R U R A L & R E M

O T E

U R B AN

E N T E R P R I S E

V I R T U AL I Z AT I O N

H O M E

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SMALL CELL FORUM

RELEASE 6.0 scf.io

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Small Cell Forum accelerates small cell adoption to drive the wide-scale adoption of small cells and accelerate the delivery of integratedHetNets.

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We have driven the standardization of key elements of small cell technologyincluding Iuh, FAPI/SCAPI, SON, the small cell services API, TR-069 evolutionand the enhancement of the X2 interface.

Today our members are driving solutions that include small cell/Wi-Fiintegration, SON evolution, virtualization of the small cell layer, driving massadoption via multi-operator neutral host, ensuring a common approach toservice APIs to drive commercialisation and the integration of small cells into5G standards evolution.

The Small Cell Forum Release Program has now established business casesand market drivers for all the main use cases, clarifying market needs andaddressing barriers to deployment for residential, enterprise and urban small

cells. The theme of Release 6 is Enterprise, with particular emphasis on realworld and vertical market deployments, and the role of neutral host solutionsto drive the mass adoption of small cells in business environments.

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Report title: E-SCN Issue date: 01 December 2013Version: 071.06.01

Scope

This document focuses on use cases and requirements for enterprise private branch

exchange/unified communications (PBX/UC) systems that are augmented to enableaccess via small cells within the enterprise.

In contrast to the 3GPP standards bodies, the use cases and requirements of thisdocument are not bound by a particular release schedule. Rather, they define asystem from a potentially longer-term view.

The requirements focus on high level functional needs that are normally independentof specific radio interfaces such as CDMA, UMTS and LTE. For exception cases, therequirements do not preclude supplementary requirements applicable to a specificradio interface.

In all cases, small cell technologies will augment existing macro cellular coverage andtherefore any integration between legacy PBX/UC environments and small cells mayneed to take into account issues related to co-existence enhanced capabilities withaccess to such services from the macro network. For example, there are alreadycommercial solutions that bring UC features to mobile devices that are accessible viathe macro network. The architecture requirements should address the capability toenhance such baseline capabilities via the introduction of access via an enterprisesmall cell network.


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Executive summary

The Enterprise small cell business case [SCF062] highlights that a key driver to the

uptake of enterprise small cells will be the improved voice coverage coupled withindoor mobility. The business case also indicates that there are significant additionalbenefits to enterprise small cell deployments that enable the operator to gain a morestrategic role in delivering services to the enterprise. Furthermore, it is highlightedthat as voice and data converge, there is a clear opportunity to enable enterprisevoice services, conventionally delivered by standalone PBX and/or unifiedcommunications systems, to become more tightly integrated with the coreinfrastructure of the mobile operator.

This document describes a set of requirements for enterprise small cells that enableoperators to deliver more than basic voice and mobility services to users accessing viathe enterprise small cell network. The topics include areas related to enterprisemobility, PBX interworking, unified communications interworking, access networkinterworking and enterprise it interworking for operations and maintenance (O&M)functions. Several different enterprise use cases are described examining issuesrelated to voice feature interworking, small cell-macro mobility as well as regulatoryservices.


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Contents

1. Introduction .....................................................................1

2. Definitions and abbreviations ...........................................1 3. Aspects of enterprise small cell networks ........................4 3.1 Enterprise service mobility .................................................... 4 3.2 PBX interworking ................................................................. 4 3.3 Enterprise unified communications interworking ...................... 4 3.4 Enterprise access network interworking .................................. 4 3.5 Enterprise IT-department interworking for O&M functions ......... 5 4. Use cases .........................................................................6

4.1 FMC use cases .................................................................... 6 4.2 Service consistency use cases ............................................... 7 5. Requirements ................................................................. 10 5.1 Basic mobility requirements ................................................ 10 5.2 Small cell grouping requirements ........................................ 10 5.3 Lipa and SIPTO requirements .............................................. 11 5.4 Fixed-mobile convergence for enterprise services .................. 12 5.5 Service consistency requirements ........................................ 12 5.6 Access model requirements ................................................ 13

5.7 O&M support ..................................................................... 14 5.8 Lawful intercept/CALEA requirements ................................... 15 5.9 Security ........................................................................... 15 References ................................................................................ 16

TablesTable 2-1 Definitions and Abbreviations ........................................................... 3


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Report title: E-SCN Issue date: 01 December 2013Version: 071.06.01 1

1. Introduction

The Enterprise small cell business case [SCF062] highlights that a key driver to theuptake of enterprise small cells will be the improved voice coverage coupled with

indoor mobility. The business case also indicates that there are significant additionalbenefits to enterprise small cell deployments that enable the operator to gain a morestrategic role in delivering services to the enterprise. Furthermore, it is highlightedthat as voice and data converge, there is a clear opportunity to enable enterprisevoice services, conventionally delivered by standalone PBX and/or unifiedcommunications systems, to become more tightly integrated with the coreinfrastructure of the mobile operator.

This document assimilates requirements and use cases derived from contributionsmade by companies of the Small Cell Forum (SCF). In particular the requirementsaddressing the important intersection between established 3GPP defined voiceinterworking with enterprise IP-PBX (VINE) [ 1 ] and the SCF Network Working Groupenterprise small cell architecture definition [SCF067]

NOTE: This document represent a revision of an earlier document published bythe Small Cell Forum in 2009.

2. Definitions and abbreviations

Term DefinitionCPN From TISPAN [ 2 ]: Customer premise networkCPN device From TISPAN [ 2 ] :

A device that is physically installed in the CPN allowing useraccess to network services; this can be a customer networkgateway with gateway functionalities towards the NGN, or acustomer network device being the end user terminal

Customer networkdevice (CND)

From TISPAN [ 2 ]:CPN device enabling the final user to have direct access toservices through a specific user interfaceNOTE : CNDs can be dedicated to the internet, conversational andaudio-video services. But they could be also consumer electronicsequipment and other devices that may have nothing to do withthese premium services (e.g. services performing a contentsharing within a CPN, typically between a PC and a musicsystem).

Customer networkgateway (CNG)

From TISPAN [ 2 ]:CPN device acting as a gateway between the CPN and the NGN

NOTE : CNG is able to perform networking functions from physicalconnection to bridging and routing capabilities (L1 to L3), but alsopossibly implementing functions related to the service support (upto L7).

Enterprisecommunicationssystem

The set of enterprise communication functions that logically residein the enterprise, including PBX, unified communications elementsand handsets.NOTE : The definition allows PBX and/or unified communicationsfunctions to reside either on premise or be hosted by a serviceprovider.

E-SC Enterprise small cellSmall cell group One or more ESC units serving a single enterprise that, through

overlapping coverage, provide a larger contiguous coverage area

than that of a single ESC. A small cell group can support small cell


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Term Definitionto small cell handover (within the group) without involving theoperator network. As such, from a signalling point of view, thesmall cell group can appear as a single, larger cell to the operatornetwork.

An enterprise may have numerous small cell groups.Geographically dispersed sites would tend to be serviced bydifferent groups. At a single site, multiple groups may also beused (for example, different floors of a building).NOTES :• With the 3GPP small cell architectures, small cells of a small cell

group must use the same small cell-GW in order to supportintra-group handovers without signalling to the operatornetwork.

• Small cell to small cell handover between small cells of differentgroups (both belonging to the same enterprise) shall bepossible.

• With the 3GPP small cell architecture, signalling to the operator

network can be avoided if the affected small cells share thesame small cell-GW.• With the 3GPP small cell architecture, since the non-access

stratum signalling is protected up to the MME, it may need tobe involved in small cell to small cell handover.

• Some operators may require visibility of small cell to small cellhandovers within the group. As such, the signalling bypasscapability for small cell to small cell handover may be activatedor deactivated based on operator preferences. The small cells ofa given small cell group need not have the same CSG list.

• The small cell group may be configured by the small cellmanagement system, e.g., using an extension to the TR-196data model.

Small cell zone A small cell zone encompasses the small cell groups servicing asingle enterprise. The small cell groups of a small cell zone may ormay not be geographically dispersed.Consistent with the Small Cell Forum enterprise Services WGdefinition, features and services offered within an enterprise smallcell zone can be a superset of those available in the macronetwork.

Enterprise small cellgateway

The ESCG is the point of integration between the ESCN and theenterprise services network. From classical 3GPP architecturepoint-of-view, the ESCG includes Local-GW functionality to enablelocal IP access by suitable authorized enterprise users. Inadditional to IP access, the ESCG delivers key functionality thatenables integration into the enterprise PBX/UC environment and

network management systems. Importantly, from a securityperspective, the ESCG function does not have any visibility ofnon-enterprise traffic.The enterprise small cell gateway function is further defined aspart of the Small Cell Forum’s Enterprise small cell architecture document [SCF067].

Enterprise small cellconcentrator

The ESCC is a point of aggregation for the enterprise small cellnetwork. The ESCC includes functionality that is able to mask idleand connected mode mobility within the enterprise small cellnetwork. From a security perspective, in open and hybriddeployments, the ESCC function has visibility to traffic generatedby non-enterprise users.The enterprise small cell concentrator function is further defined

as part of the Small Cell Forum’s Enterprise small cell architecture


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Term Definitiondocument [SCF067].

NGN Next generation network

Table 2-1 Definitions and Abbreviations


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3. Aspects of enterprise small cell networks

3.1 Enterprise service mobility

Enterprise service mobility refers to the extension of enterprise communications andservices beyond wired desk phones to mobile devices anywhere coverage exists,including being able to access such services from the macro network and also from theenterprise small cell network. For a service to be mobile implies that the service canbe accessed whilst the consumer of the service is mobile, including whilst movingacross the macro network, within the enterprise small cell network and transitioningbetween the small cell and macro environments.

3.2 PBX interworking

Whereas enterprise service mobility more generally describes enterprise servicespresented to a mobile device, PBX interworking supports a more specific feature set

made available to the mobile device.

PBX interworking provides enterprise voice features, conventionally only available onwired desk phones, and enables access to such services from enterprise mobiledevices. For feature phone type mobile devices, accessible enterprise capabilitiesmight be limited to those that can be triggered by digit key sequences. Alternatively,smartphone type mobile devices, coupled with a mobile device application andsophisticated user interface, could potentially expose all services and featuresaccessible via wired desk phones.

PBX interworking must account for enterprises possessing PBX products from multiplevendors, and potentially PBX systems. However, 3GPP focus in its VINE study hasconcentrated on SIP based systems. It is assumed that the enterprise environment iscompatible with the 3GPP VINE approach of SIP based enterprise application serversthat may be centrally hosted or located on the enterprise premise. In particular,requirements around integration with legacy H.323 systems are not addressed.

3.3 Enterprise unified communications interworking

Unified communications systems automate and unify all forms of communicationswithin an enterprise. Typically unified communications systems augment PBX systems.Whereas the PBX system provides call services, UC incorporates other capabilities thatmay include instant messaging, unified messaging, speech access, collaboration toolsand business process integration (that in turn make use of PBX capabilities). As withPBXs, UC deployments greatly differ from vendor to vendor.

The enterprise small cell network needs to make assumptions around the realization ofthe enterprise UC environment. In particular, it is assumed that the enterpriseenvironment is compatible with the 3GPP VINE approach of SIP based enterpriseapplication servers that may be centrally hosted or located on the enterprise premise.

3.4 Enterprise access network interworking

Whereas enterprise mobility deals with presentation of enterprise communicationsservices and capabilities to the mobile device, enterprise access network interworkingencompasses:


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• Universal access – The radio technologies used by mobile devices to accessthe network, such as UMTS or CDMA, LTE, Wi-Fi, and WiMAX

• Access independent service continuity – Maintaining voice and data sessionsbetween handovers involving different access types, including whentransitioning between small cell access network and the macro-cellular accessnetwork.

• Access independent service consistency – Maintaining a consistent set ofenterprise services irrespective of access type - i.e., access via the small cellaccess network or via the macro-cellular access network.

3.5 Enterprise IT-department interworking for O&M functions

In residential settings, small cell management is entirely in the operator domain.Though operators will always require control of small cell systems in the enterprise,there is an equally compelling case supporting some degree of management visibilitywithin the enterprise. An O&M functional boundary must be defined for managementoperations that may be delegated to the enterprise.


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4. Use cases

4.1 FMC use cases

As a general rule FMC use cases are established through the many enterprise mobilitysolutions in the market. The introduction of small cell technologies in the enterpriseshould ensure consistency of the use cases, whether the mobile device is in the macronetwork or camped on an enterprise small cell. The following use cases intend tohighlight key scenarios and/or present existing deployment considerations.

4.1.1 Use case: Small cell interworking with TISPAN CNG function

OverviewAn existing enterprise deployment incorporating TISPAN CNG functions is enhanced tosupport small cell technologies.

PreconditionsAn enterprise deployment includes TISPAN defined functions, including a customernetwork gateway (CNG) that connects to numerous SIP-based customer networkdevices. In order to support small cells, the CNG incorporates an enterprise small cellgateway that accommodates ESCs.

Flow1. Subscriber’s UE is authorized to access enterprise IP PBX services2. ESC gateway registers UE with IMS3. UE user dials extension number of IP extension.4. Call is routed ESC-> ESC gateway -> S-CSCF -> enterprise-AS, based on UE

authorization status.5. IP extension user dials IP extension associated with UE.6. Call is routed IP PBX-> enterprise-AS -> S-CSCF -> ESC gateway ->ESC,

based on location information of UE in S-CSCF.

Notes (optional)CNG and CND in TISPAN model [ 2 ] .

4.1.2 Use case: Groupware collaboration on the mobile device

OverviewGroupware is a term used to describe collaborative software, which allows sharinginformation among members of a group targeted at a common task. For example,assistant can plan meetings for his/her boss (time management), or maintain phone

numbers across the organization (contact management).

A groupware server enables collaboration, regardless of location, via the Internet or acorporate intranet and to work together in a virtual atmosphere. Through a small cell,a mobile device can participate in collaboration with other devices in the enterprisedomain.

PreconditionsESCs are accommodated in LAN that has an existing groupware server serving fixednetwork enterprise user devices. An enterprise small cell gateway is enhanced withlocal gateway functionality.

Flow1. A subscriber is authorized to access enterprise groupware services

http://www.webopedia.com/TERM/I/intranet.htmlhttp://www.webopedia.com/TERM/I/intranet.html


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2. On the subscriber’s mobile device, the user activates the groupwareapplication, which is provisioned to use the enterprise small cell APN for LIPA.

3. The groupware application establishes an IP session to groupware server viathe LIPA gateway.

4. When off-net, the groupware application uses its regular macro network APNand connects to the enterprise groupware server through a VPN tunnel, TLSconnection or similar.

4.1.3 Use case: Call initiation via smartphone ‘over the top’ application

OverviewMany enterprise mobility solutions are deployed today where UC (unifiedcommunications) capabilities are rendered on a smartphone with an ‘over the top’(HTTP(S) based) application. When enterprise users access the mobile network viasmall cells, it is important that these same UC capabilities are available.

Preconditions• An enterprise communication system has a premise based UC solution that

includes HTTP(S) based service capabilities.• Enterprise User A has a mobile smartphone with an installed HTTP(S)

application. User A may be camped on an enterprise small cell, or anywherein the macro network.

• This application interacts with the enterprise HTTP(S) Application Server

Flow• Using the ‘over the top’ HTTP(S) application, User A views the corporate

directory to search for a colleague (User B).• User A selects User B from the corporate directory and initiates the call.• User B answers the call on a device that is ringing.•

Other devices stop ringing and User A and B begin conversing on the call.Notes (optional)This scenario was originally proposed for inclusion in the 3GPP VINE study [ 1 ] , butwas considered beyond the scope of 3GPP.

4.2 Service consistency use cases

4.2.1 Use case: Call initiation via enterprise domain short code diallingplan

The use cases of this section highlight service interactions between legacy circuitswitched domain services (such as supplementary services or voicemail) andenterprise IMS-AS based services for enterprise mobile devices.

OverviewFrom an enterprise mobile device camped on an enterprise small cell, a user attemptsto dial another enterprise user through a valid enterprise short code number.

Preconditions• An enterprise communications system has a premise based enterprise IMS-

AS implementing a corporate dial plan feature where enterprise Users areable to contact other enterprise uses through a short number (typically 4-6digits).

• Enterprise User A has a mobile device and is camped on one of theenterprise’s small cell.


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• Enterprise User A is authorized to access enterprise PBX features• Enterprise User B has any enterprise device (IP phone, PBX or 3GPP mobile

device). User A and User B may be anywhere. Where available, User A and Bmobile devices register with coverage-enhancing systems deployed by theenterprise, such as those based with small cells and/or Wi-Fi.

Flow• User A initiates a call toward User B with the IP-PBX ‘short code’ number

provisioned within the IP-PBX integrated with the enterprise IMS-AS.• The ESC intercepts the request and forwards to the enterprise small cell

gateway which then signals the enterprise IMS-AS via the S-CSCF• Based on service logic within the enterprise IMS-AS, a subset or all of User B

devices ring either simultaneously or in a particular sequence.• User B answers the call on a device that is ringing.• Other devices stop ringing and User A and B begin conversing on the call.

Notes (optional)

Refer to requirement FMC-03 (section 5.4) - ‘Service interaction management betweenenterprise and CS domains’.

4.2.2 Use case: Call initiation via circuit switched domain short code

OverviewFrom an enterprise mobile device camped on an enterprise small cell, a userattempts to dial a short code number that is not a valid enterprise short codenumber.

Preconditions• An enterprise communications system has a premise based enterprise IMS-

AS implementing a corporate dial plan feature where enterprise users areable to contact other enterprise uses through a short number (typically 4-6digits).

• Enterprise User A has a mobile device and is camped on one of theenterprise’s small cells.

• User B has any device, but is not an enterprise user.• User A and User B may be anywhere.• Where available, User A and B mobile devices register with coverage-

enhancing systems deployed by the enterprise, such as those based withsmall cells and/or Wi-Fi.

Flow• User A initiates a call toward User B with a ‘short code’ number that is not

provisioned in the enterprise IMS-AS based IP-PBX system.• The ESC intercepts the request and forwards to the enterprise small cell

gateway which then signals the enterprise IMS-AS• The enterprise IMS-AS is unable to route the call, as the short code is not

recognized. The number translation functionality within the operator network,e.g., implemented as a second IMS-AS, is then queried to determine a callrouting.

• The number translation functionality is able to map the short code to a diallednumber. The operator’s IMS-AS forwards the call to this number.

• The User B device rings.


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Notes (optional)Refer to requirement FMC-03 (section 5.4) - ‘Service interaction management betweenenterprise and CS Domains’.

4.2.3 Use case: Circuit switched domain call waiting and call holdduring an enterprise call

OverviewA mobile enterprise user involved in an enterprise call (serviced by an IP-PBX)receives a CS domain call waiting notification when a 3rd party attempts to callhis/her mobile device.

Preconditions• An enterprise has a premise-based enterprise IMS-AS integrated with its IP-

PBX system.• Enterprise User A has a mobile device and may be serviced through the

macro network or small cell.• Enterprise User B has any device.• User C has a circuit switched 3GPP mobile device and is in the macro

network.• User A and User B are on a call serviced by the enterprise IMS-AS.

Flow• From the macro network, User C initiates a call towards User A through with

the number assigned by the operator.• User A receives a call waiting indication.• User A can put User B on hold and answer the call from User C.• Upon finishing with User C, User A can reconnect with User B to continue with

the enterprise call.

Notes (option a l)Refer to requirement FMC-03 (section 5.4) - ‘Service interaction management betweenenterprise and CS domains’.

4.2.4 Use case: Circuit switched domain voicemail – enterprise calleebusy

OverviewEnterprise voicemail will be available for enterprise users contacted through theirenterprise identity (short code or full enterprise number).

Preconditions• The user has enterprise voicemail provisioned.• The service provider supports defined interaction between standard call

forwarding and enterprise IMS-AS based voicemail• An enterprise user is currently on a voice call on an enterprise device that

could include a mobile device or a desk phone.

Flow1. A caller attempts to dial the enterprise user via an enterprise number (short

code or full number).2. The call is forwarded to the enterprise voicemail applications server.3. The voicemail is accessible through the enterprise voicemail application

server.


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5. Requirements

5.1 Basic mobility requirements

Basic mobility requirements cover voice and data continuity through a mobile devicehandover between various access point types.

ID DescriptionMR-01 CS session continuity between enterprise small cell and macro networks – CS session

continuity shall be maintained following user handover between small cell and macronetworks.

MR-02 PS session continuity between small cell and macro networks (LIPA and SIPTOinactive) –PS session continuity shall be maintained following user handover betweensmall cell and macro networks when neither LIPA nor SIPTO are active.

MR-03 PS session continuity between small cell and macro networks (LIPA or SIPTO active) -It is desirable to support PS session continuity when LIPA or SIPTO is active. Ifimplemented, the mobile operator may be provided a means to activate sessioncontinuity for LIPA and SIPTO data traffic (per UE and APN).

MR-04 Small cell groups – The small cell management system shall be able to support thedefinition of a small cell group, comprising a plurality of small cells in close proximity.

MR-05 CS and PS session continuity within the small cell group – Within the contiguouscoverage area offered by a group, CS and PS session continuity shall be maintainedwhen the user hands over between small cells within the group. This shall be true iftraffic offload capabilities (LIPA and SIPTO) are activated or deactivated.

MR-06 Intra-group soft handoff - Soft handoff may be optionally supported by the enterprisesmall cell system for 3G. If it is supported, operator policy shall dictate whether softhandover is activated.

MR-07 Inter-group handoff – CS and PS session continuity shall be maintained followinghandover between two small cell groups that have overlapping coverage. A handover

between two groups is predicated on successful authorization in the target small cellzone (either through open access or closed subscriber group access schemes).MR-08 Intra-group / small cell zone handoff - The system may optionally support handoff

without involving core network signallingNOTE: With the 3GPP small cell architecture, intra-group handoffs without involvingthe core network are only be supported when the affected small cells use the samesmall cell-GW.NOTE: With the current 3GPP small cell architecture, intra-group handoffs need tosignal the MME functionality in the EPC.

MR-09 Inter-group handoff optimization – Any interruption to CS and/or PS service duringhandoff operation should be minimized.

5.2 Small cell grouping requirements

Small cell grouping allows increased contiguous small cell coverage area and/orincreased capacity through the deployment of multiple small cells that collectivelyemulate a higher powered, higher capacity small cell.

ID DescriptionFC-01 Group self-optimization – Certain small cell and group configuration settings may be

automatically adjusted to an optimal value defined by small cell grouping logic:Further details of RF self-optimization are covered in [SCF066].

FC-02 Scalability - The enterprise small cell zone must scale to support large, potentiallygeographically dispersed enterprises where a small cell zone can include severalgroups, each of which incorporating 10’s or potentially 100’s of small cells.

FC-03 Signalling optimization - Highly frequent intra-group idle and connected mode


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ID Descriptionhandovers must be assumed. Intra-group handovers procedures shall be optimized toreduce signalling in the operator network (core network for UMTS and evolved packetcore for LTE).

FC-04 Intra-group/inter-small cell communications - The enterprise small cell network maysupport a secured logical link between small cells within a group in support of thefollowing functions:Radio resource coordination including interference managementNeighbour list sharingLoad sharingSoft handover supportNOTE: Whilst some of these capabilities have been defined to be supported by the X2interface for LTE based enterprise small cells, corresponding functionality may need tobe defined for 3G based small enterprise small cells.

FC-05 Local media optimization – Subject to operator approval and policies, it shall bepossible for media exchanged between calls involving a mobile device camped on asmall cell and another device in the enterprise to be locally switched. If enabled, thesignalling path will be anchored in the operator network (e.g., using S-CSCF) whilethe user plane is contained in the enterprise, thereby bypassing the operator network.

FC-06 IPSec aggregation - It is desirable to reduce the number of IPsec tunnels supportedper enterprise site mainly to reduce the tunnelling requirement on the operatornetwork.The enterprise small cell network may optionally support an enterprise small cellconcentrator function that provides IPsec aggregation functionality that aggregatesthe IPsec tunnels to/from small cells into a single IPSec tunnel to/from the small cell-GW.IPsec support between ESC and enterprise small cell concentrator within theenterprise network may be required as the ESCC handles non-enterprise user traffic.

5.3 Lipa and SIPTO requirements

Based on operator and enterprise preferences LIPA and SIPTO capabilities defined by3GPP [ 3 ] may be supported for enterprise networks.

ID DescriptionLS-01 Local IP access - Mobile operators shall be able to enable access to local IP services

through activation of LIPA support (per UE and APN) in the enterprise small cell zone.The LIPA APN will be associated to a small cell group. Many small cell groups may beassociated to the same APN. As such, it will be possible for the APN to map to anentire small cell zone (if each small cell groups in the small cell zone is associated tothe same APN).NOTE: The operation of local IP access may have regulatory implications, see section6.8

LS-02 SIPTO in the local network - Mobile operators shall be able to offload selected internetbound IP traffic from the core network to broadband network through seamlessactivation of SIPTO in the enterprise small cell zone.NOTE: The operation of selective IP Traffic offload in the local network may haveregulatory implications, see section 6.8

LS-03 SIPTO above the RAN - Mobile operators shall be able to offload selected internetbound IP traffic from the core network to broadband network through seamlessactivation of SIPTO outside of the enterprise NetworkNOTE: The operation of Selective IP traffic offload above the RAN may haveregulatory requirements, which can be met by the operator using traditional methodsapplied for core network routed traffic. See section 6.8 for further discussion.


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5.4 Fixed-mobile convergence for enterprise services

This section documents services defined in the enterprise domain that will be availableon mobile devices and accessible to authorized enterprise users.

ID DescriptionFMC-01 IP-PBX services on mobile devices – As a general rule, IP-PBX services and features

available to wired lines shall be accessible on mobile devices accessing the networkthrough small cells. Operator policies and / or technical limitations may result in aservice subset available to mobile devices. Examples of converged services includeshort code dialling, parallel alerting, media/call transfer (attended and unattended)and all the other features of a particular enterprise IMS-AS based PBX.NOTE: Some complex features may not be practical on a feature phone, and mayrequire a smartphone with an installed client application, such as an ‘over the top’application utilizing HTTP(S) or some other signalling mechanism over the PS(packet switched) network.

FMC-02 UC services on mobile devices - For enterprise networks containing enterprise IMS-AS based UC (unified communications) capabilities, services available to wired linesshall be possible on mobile devices accessing the network through small cells.Operator policies and/or technical limitations may result in a service subsetavailable to mobile devices.NOTE: Some complex features may not be practical on a feature phone, and mayrequire a smartphone with an installed client application, such as an ‘over the top’application utilizing HTTP(S) or some other signalling mechanism over the PS(packet switched) network.

FMC-03 Service interaction management between enterprise and circuit switched domains –Logic controlled by the operator network must appropriately manage serviceinteractions between services defined in the enterprise and circuit switcheddomains.Specific service interactions requiring management logic need to be identified on acase-by-case basis. As they may depend on operator preferences, the CS domainservices offered by the operator as well as the enterprise Mobility solution offeredby the operator, the identification of service interactions requiring attention is out ofscope of this document. To illustrate the spirit of this requirement, a few examples will be given:• For short code calls originated via the small cell, the operator must be in control

of the activation of the number translation process.• For enterprise calls that are subject to enterprise domain mid-call services,

operator domain call services such as call waiting and call hold shall still function.

Note: Some features, such as enterprise dialling plan, may not be available tohandsets while camped on to the macro network.

FMC-04 TISPAN consideration - For enterprise architectures involving SIP-based small cells,the TISPAN model CNG [2] shall be considered when defining a ESC function basedin the enterprise premise .

FMC-06 Support for multiple IP-PBX types – Support shall be given for enterprisedeployments containing more than one premise-based IP-PBX type that may includeIP-PBX’s from different manufacturers. The architecture assumes that such IP-PBXsare compatible with 3GPP’s VINE architecture [ 1 ] .

5.5 Service consistency requirements

Enterprise UC/PBX integration provides enterprise services to the mobile userauthorized to access enterprise services. The availability these capabilities shall notinterfere with services provided to users who are not authorized to access enterpriseservices and who are served by the service provider core network. Furthermore, the

access to enterprise features when suitably authorized shall not interfere with services


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defined in the operator network, in particular supplementary services defined in [ 4 ]and [ 5 ] and emergency calling services defined in [ 6 ].

ID Description

SC-01 CS domain service consistency – Services in the macro network shall be available tothe mobile users when camped on a small cell and authorized to access enterpriseservices. This includes the numerous supplementary services defined by 3GPP [ 6 ] .In some cases service conflicts can occur between services in the macro network andthe enterprise IMS-AS based PBX/UC system. For such cases, a mechanism isrequired to resolve any such conflicts on a case-by-case basis. This mechanism mustbe controlled by the operator network.

SC-02 Service consistency through handover – Consistent with macro network handovers,services defined in the enterprise IMS-AS and macro networks shall continue tofunction transparently following a handover between macro and enterprise small cells,and in between two enterprise small cells, subject to policies of operator or enterprisepolicies:Enterprise policies may restrict enterprise domain services from functioning following

handovers from an enterprise small cell to the macro network.Operator policies may restrict CS/PS domain services from functioning followinghandovers from the macro network to an enterprise small cell.

SC-03 Enterprise domain service consistency in the macro network – Selected enterprisedomain services available to the mobile user while camped onto a small cell within asmall cell group shall be available to mobile users in the macro network.

SC-04 Access to emergency calling services – Access the emergency calling in the macronetwork shall not be impeded by the operation of the enterprise small cell network.When an enterprise user, camped on to an enterprise small cell and who is authorizedto access local IP-PBX/UC services makes an emergency call, the call will always behandled by the service provider core network.

5.6

Access model requirementsAn access model defines two aspects pertaining to authorization:

• User access – Determines users allowed to camp on to a small cell within asmall cell group,

• Capability restrictions – Features and capabilities available to a particularuser while camped on to small cell within a small cell group.

The requirements in this section identify three access modes with associated useraccess and capability restrictions in addition to associated requirements related tosupport special cases and enterprise access management.

ID DescriptionAM-01 Closed access/restricted association mode support – Through a provisioning

mechanism, it shall be possible to restrict the use of small cells within a small cellgroup to specific mobile users. Such capabilities will re-use similar capabilities definedin 3GPP.CDMA case: closed access support (restricted association) shall be realized by the ACL(access control list) capability [ 7 ].UMTS case: Closed access support shall be realized by the CSG (closed subscribergroup) capability defined in [ 4 ] .LTE case: [ 4 ] In such a mode, unauthorized mobile users will not be allowed to camp on any smallcell within the small cell group.

AM-02 Exceptions for closed access /restricted association small cell groups – For mobileusers that are not authorized to use small cells within a small cell group in closed


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ID Descriptionaccess mode, it must be possible to place emergency calls through the small cell.Other features may be optionally supported, such as outgoing call whitelists.

AM-03 Open access/association mode support – Through a provisioning mechanism, it shallbe possible to place a small cell group in an open access / association mode asdefined by 3GPP [ 4 ] , where any mobile user is authorized to use any of the smallcells within the group. As such, any mobile user may be allowed on camp on smallcells within the small cell group.

AM-04 Hybrid access mode support – It shall be possible to enable a hybrid access modewhere:Mobile users belonging to the small cell group ‘closed subscriber group’ are authorizedfor access to the enterprise features as allowed by the enterprise UC/PBX system.Mobile users not belonging to the small cell group ‘closed subscriber group’ areauthorized to use a limited of the enterprise features and / or are authorized to camponto a subset of the small cells within the small cell group (for example, any UE mightbe able to camp on to a small cell in the lobby, whereas other mobile devices maycamp onto all small cells within the premise). The specific features sets for specificmobile devices shall be manageable based on the operator or enterprise policies.

AM-05 Enterprise closed subscriber group management – For small cell groups employingclosed access or hybrid access modes, it shall be possible for the operator to delegatesubscriber group provisioning to the enterprise.

AM-06 Hybrid resource partitioning support – For small cells operating in hybrid mode, itshould be possible for the operator to be able to define the resource partitioning suchthat a minimum set of resources can be associated with mobile users belonging to thesmall cell group ‘closed subscriber group’.

5.7 O&M support

This section highlights O&M functions required by the operator and enterprise insupport of enterprise small cells.

ID DescriptionOM-01 Small cell group definition - It shall be possible for the small cell's hosting party to

add /remove /replace small cells in the enterprise subject to operator agreement.The incremental addition and/or removal of small cells requires updates to theneighbour list and associated TR-069 database that is maintained in the operatornetwork. In addition, the addition and/or removal of an enterprise small cell maytrigger a reconfiguration of the ESCs within the small cell group, e.g., updating radioresource parameters, including EIRP.

OM-02 Small cell fault management at the enterprise - Subject to operator and small cellhosting party agreement, it shall be possible for the small cell hosting party tomonitor selected status information of network connectivity and radio conditions ofthe small cell (e.g. IPSec tunnel status, radio link up/down).

OM-03 Small cell performance management at the enterprise - Subject to operator and smallcell hosting party agreement, it shall be possible for the small cell hosting party toobtain selected information on key performance indicators of the small cell (e.g. datathroughput, number of packets in/out, number of voice minutes.)

OM-04 Provisioning scaling - The enterprise small cell provisioning system shall support alarge membership group that shall be able to scale up to 100,000 subscribers perCSG

OM-05 CSG batch provisioning support - The enterprise small cell provisioning system shallprovide the enterprise with batch provisioning mechanism to add or remove identitiesfrom the CSG list. Any updates must be validated by the operator network beforebecoming active.

FFS: Must new members belong to the same operator that provides the small cell?OM-06 CSG list management - The enterprise small cell provisioning system shall provide the


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ID Descriptionenterprise with a near real-time system to update the membership (removing oradding a user identity from a CSG). The latency between a CSG update and activationshall be in the order of several minutes. Any updates must be validated by theoperator network before becoming active.

5.8 Lawful intercept/CALEA requirements

The network operator, access provider, or service provider is legally required toprovide law enforcement agencies with access to telecommunications traffic that is tobe intercepted on request, as defined by the laws of each country in which it providesservice. As a communications service provider (CSP), mobile operators must complywith these lawful intercept (LI) requirements. Traditionally, these requirements havebeen readily implemented within the mobile operator’s core network, via intercept atthe serving GPRS support node (SGSN). However, in the case of small cells usingSIPTO or LIPA the situation is more complex and the precise mechanisms forcomplying with LI obligations in these cases may vary by geography and/or dependingon the network architecture.

The equipment will need to conform to the relevant requirements under national laws,with respect to the ability to intercept traffic for specified subscribers only, and withoutdetection. This would include avoiding the subject(s), or third parties, being aware ofthe intercept taking place and ensuring that nobody but authorized individuals(including members of the enterprise IT staff), would be able to determine that one ormore individuals, closed user groups, or small cells themselves are subject tointercept.

ID DescriptionREG-01 LI/CALEA capabilities - A system supporting direct access to the Internet and/or PSTN

from the enterprise small cell may be required to provide lawful intercept/CALEAfunctionality.

5.9 Security

This section highlights security requirements for the enterprise small cell network thatare over an above the functions typically required to be supported by conventionalsmall cells.

ID DescriptionSEC-01 Enterprise user authorization – A means to authorize an enterprise mobile user shall

be supported and optionally enabled before enterprise users can make use of

enterprise capabilities through a wireless device that may be camped on a Small Cellor macro network.SEC-02 Eavesdropping prevention – The architecture should prevent the eavesdropping on

communications sessions from non-enterprise users, including by skilled enterprise ITstaff

SEC-03 Separation of small cell enterprise LAN traffic– The enterprise may require the smallcell traffic to be separated from other enterprise LAN traffic, e.g., by the use ofseparate address pools, or separate VLAN allocations, or separate VRF instances.


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Report title: E-SCN Issue date: 01 December 2013

References

1 3GPP TR 22.809 v0.2.0 Feasibility Study on Support for 3GPP Voice Interworking

with enterprise IP-PBX (VINE) (Release 11) -http://www.3gpp.org/ftp/specs/html-info/22809.htm 2 ETSI TS 185 003 v.2.3.1: Telecommunications and Internet converged Services

and Protocols for Advanced Networking (TISPAN); Customer Network Gateway(CNG) Architecture and Reference Points -http://pda.etsi.org/pda/home.asp?wki_id=C0R8zgTZPWYagcZeXw8Bl

3 3GPP TR 23.829 Local IP Access and Selected IP Traffic Offload -http://www.3gpp.org/ftp/specs/html-info/23829.htm

4 3GPP TS 22.220 Service Requirements for Home Node B (HNB) and Home eNodeB (HeNB) - http://www.3gpp.org/ftp/Specs/html-info/22220.htm

5 3GPP TS 22.004: ‘General on Supplementary Services’:http://www.3gpp.org/ftp/Specs/html-info/22004.htm

6 3GPP TS 22.002 v11.0.0: Circuit Bearer Services (BS) supported by a Public LandMobile Network (PLMN) (Release 11) http://www.3gpp.org/ftp/Specs/html-info/22002.htm

7 3GPP2 TS A.S0024-B.V1, ‘Interoperability Specification (IOS) for Femtocell AccessPoints’
http://www.3gpp.org/ftp/specs/html-info/22809.htmhttp://www.3gpp.org/ftp/specs/html-info/22809.htmhttp://pda.etsi.org/pda/home.asp?wki_id=C0R8zgTZPWYagcZeXw8Blhttp://pda.etsi.org/pda/home.asp?wki_id=C0R8zgTZPWYagcZeXw8Blhttp://www.3gpp.org/ftp/specs/html-info/23829.htmhttp://www.3gpp.org/ftp/specs/html-info/23829.htmhttp://www.3gpp.org/ftp/Specs/html-info/22220.htmhttp://www.3gpp.org/ftp/Specs/html-info/22220.htmhttp://www.3gpp.org/ftp/Specs/html-info/22220.htmhttp://www.3gpp.org/ftp/Specs/html-info/22004.htmhttp://www.3gpp.org/ftp/Specs/html-info/22004.htmhttp://www.3gpp.org/ftp/Specs/html-info/22002.htmhttp://www.3gpp.org/ftp/Specs/html-info/22002.htmhttp://www.3gpp.org/ftp/Specs/html-info/22002.htmhttp://www.3gpp.org/ftp/Specs/html-info/22002.htmhttp://www.3gpp.org/ftp/Specs/html-info/22002.htmhttp://www.3gpp.org/ftp/Specs/html-info/22002.htmhttp://www.3gpp.org/ftp/Specs/html-info/22004.htmhttp://www.3gpp.org/ftp/Specs/html-info/22220.htmhttp://www.3gpp.org/ftp/specs/html-info/23829.htmhttp://pda.etsi.org/pda/home.asp?wki_id=C0R8zgTZPWYagcZeXw8Blhttp://www.3gpp.org/ftp/specs/html-info/22809.htm

071 enterprise small cell networks

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