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2 Nortel Confidential Information

BUSINESS MADE SIMPLE

Femto-Cell Network Architecture Considerations

NortelOctober, 2007

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Topics addressed• Generic Connectivity Requirements

• Femto Architecture Options• PPP Termination• Tunnelled R-P• Tunnelled Abis• Tunnelled PPP

• Considerations:• Femto-cell authentication and Security• Mobility/Seamless VoIP Handoff

• Reuse of IOS interfaces• Protocols to use (P-P-like, PPP/ROHC session context transfer)

• Accounting• QoS• Provisioning

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Generic Connectivity Requirements

FEMTO

General Operation:• The Femto is connected by the customer to

their existing home local network. An address is assigned to the local ETH interface with DHCP.

• Femto ‘proxy clients’ can initiate WAN connectivity (IPSec tunnel establishment) to a wireless provider security gateway.

• Ideally, the existing PDIF framework can be reused. Once the IPSec tunnels are established between Femto-cell and the PDIF, both Voice and Data traffic can be exchanged between the AT and the network.

HomeRouter(NAT)

Cable /DSL

Modem

PC

Border Router

ISP Cellular Provider

Security GW

IPSec Tunnel

AT

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Reachability Requirements for Femtocell:

1. Femto must connect to the wireless provider access network in order to support mobility. There is a secure connection between the access network and the f-BTS

2. Internet breakout: Must have the possibility of local breakout for accessing internet (by-pass)

3. LAN access: Must enable access for the wireless device to devices on the local area network.

Internet

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HRPD / 1x Data – Terminate PPP

• PPP terminated at the FemtoCell – Data tunneled in IPSec tunnel to PDIF

• Mobility• Mobile IP between PDSN and PDIF

– not seamless• Need data integrity solution to

enhance HO (bicasting / fwd)

• Authentication• Same as macro (CHAP or MIP)

• QoS• Currently no solution – PDIF needs

a Ty-like interface.• Additional interface to f-BTS

required.

• Local Breakout:• Based on split tunneling.

f-BTSHRPD

MS

ISP

PDIF

HA

HRPDBTS

IPS

ec RNC

PDSN

policy

New

policy

New

FHO

New

AAA

SA = HOADA = peer

SA = HOADA = peer

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Local breakout – Reverse Link

IPSec

L2Termination Classifier

Forwarding requirements (looks at SA, DA)If DA = {internet, local lan} fwd to Proxy Client Else fwd to IPSec

ETH

Extract the IP frame from OTA encapsulation

RAN Interface Encap.

IP

Encapsulate the IP frame in the appropriate RAN specific formatWiMax : R6 (GRE)LTE : S1 (GTP)

Local NAT

Each terminal is also provided a local IP address on the Local LAN. The NAT inserts the address as the SA field.

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HRPD / 1x Data – Tunneled R-P

• Tunnel R-P interface between PDSN and f-BTS• Scalability on legacy PDSN

equipment

• Mobility• Inter-RNC mobility – leverage

cross-connectivity (A16/A17/A18/A19)

• Idle mobility (A13)

• Authentication• Same as macro (CHAP or MIP)

+ A12

• QoS• Same as macro.

• Local Breakout• Potential to support

f-BTSHRPD

MS

ISP

SEG

HA

HRPDBTS

IPS

ec

RNC

PDSN

PPP

R-P

A12A13A16A17A18A19

AAA

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HRPD / 1x Data – Tunneled A.bis

• Tunnel A.bis between RNC and f-BTS

• Mobility• Inter-RNC / Intra-RNC

mobility may be possible

• Authentication• Same as macro (CHAP or

MIP) + A12

• QoS• Same as macro.

• No Local Breakout

f-BTSHRPD

MS

ISP

SEG

HA

HRPDBTS

IPS

ec RNC

PDSNRNCBSC

PPP A.bis

AAA

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HRPD / 1x Data – Tunneled PPP

• Tunnel PPP from AT via f-BTS to NAS/SEG

• Mobility• Mobile IP between PDSN and

NAS/SEG

• Authentication• Same as macro (CHAP or

MIP)

• QoS• Currently no solution –

possibility to leverage the PDIF framework.

• Local breakout• Not possible

f-BTSHRPD

MS

ISP

NAS / SEG

HA

HRPDBTS

IPS

ec (V

PN

)

RNC

PDSN

L2

TP

AAA

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Femtocell QoS considerationsfor cable modem deployments

• For cable modem deployments, it is desirable to leverage DOCSIS QoS capabilities, as defined by PC2.0

• For standalone femtocell, static QoS provisioning may be used, based on the DSCP marking applied by the femtocell (RL) and PDIF (FL)

• For integrated femtocell, dynamic QoS provisioning can be used, through DSX signalling from an integrated cablemodem; classification would still be based on the DSCP marking applied by the femtocell (RL) and PDIF (FL)

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Femto Service Considerations

• Voice Feature Transparency• Full set of Originating & Mid Call services

•e.g. Call restrictions, Caller ID blocking, 3WC, Call Hold, Call Waiting• Full set of Terminating services

•e.g. Distinctive Ringing, Ringback Tones, Call Forwarding, Voice Mail with MWI, Selective Call Acceptance/Diversion, Anonymous Call Diversion, Do Not Disturb

• Star Codes activation•e.g. Call Forwarding, Caller ID Blocking, Cancel Call Waiting, Local Star Codes

• Regulatory services•LNP, E911, Lawful Intercept

• Data Services Transparency• Leverages existing cellular packet data infrastructure to provide

seamless transparency of existing data services

• Billing and Back-office Integration • Same CDMA Billing format used • Common Fault and Performance management platform (CNM)

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Femto Key Issues Considerations• Carrier IP access Vs Internet Access

• Where is internet traffic segregated from carrier IP traffic?

• Femto/Macro Handoffs - Like to Like Vs. Like to Different• 1x to 1x (Like to Like) has been the focus to date.• Expect Like to Different in the future. E.g. EVDOrA femto to 1x macro

• Authentication & Authorization• Should 1x network AC be used to authentication of 1x homed femto users?• Where is femto authorization list kept, managed, etc.

• QoE/QoS/Reliability• Back-haul n/w assumed to be outside of operators control.• Also question of QoS in the consumer LAN. RF coverage, Through-put/jitter, etc.

• Capacity• How much capacity is required on the back-haul.• Is a new QoS capable WLAN AP needed to ensure throughput?

• Directional HO• Single radio characteristics of 1x to 1x femto to macro demands network assistance.

• Location / Location Based Services• Femto solutions need answer for location data. GPS, provisioned, …

• Service Seamlessness• IMS based solution need to address issues with service seamlessness.

• Regulatory – Licensed Spectrum – RF Interference, 911, CALEA,…

• RF Spectrum / Macro Interference considerations.

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