EV-DO Roaming Update

EV-DO UpdateMarch 2005

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Overview

• EV-DO gaining traction in CDMA community

• Like all packet data services, roaming will be a critical to EV-DO

• Two areas important for EV-DO roaming:

– Operator Network interconnection

– Proper System Selection

EV-DO UpdateMarch 2005

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References

• SKT has presented EV-DO IRT contributions:

– New EV-DO nomenclature– Architecture and call flow– Cited Issues: System Selection, A12, Terminal

Interoperability, Billing (SO59), Fraud– Emphasized need for A12 authentication

• Standards

– IS-878 - Interoperability Specification (IOS) for High Rate Packet Data (HRPD) Access Network Interfaces

– IS-856 - CDMA2000 High Rate Packet Data Air Interface Specification

– IS-835 - Wireless IP Network Standard– IS-638-C – Includes PRL support for EV-DO

EV-DO UpdateMarch 2005

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Reference Architecture

EV-DO UpdateMarch 2005

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Operator Network Interconnection

• From a roaming perspective, most issues are same as 1xRTT

• New version of Document #79 will cover EV-DO

• Exception is A12 authentication, which is optional

• Operator consensus moving toward performing A12 authentication

• Legacy Issues facing EV-DO:

– CRX vs. Bilateral Interconnection– Simple IP, L2TP, or Mobile IP– Security issues: firewall configuration, etc.

EV-DO UpdateMarch 2005

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EV-DO System Selection Issues Overview

• System Selection is already a challenge for operators

• PRL construction to support roaming is complicated

• Problems in PRL construction can be costly

• EV-DO system selection requires a new PRL format

(IS-683-C)

EV-DO UpdateMarch 2005

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Hybrid Mode

• It’s assumed most operators will deploy EV-DO terminals configured in hybrid mode

• Hybrid mode refers 1xRTT/EV-DO capable devices which select EV-DO system using associated 1xRTT systems

• In Hybrid mode, 1xRTT and EV-DO system effectively assume a master/slave relationship.

• The new IS-683-C format supports this implementation

EV-DO UpdateMarch 2005

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• The PRL is :– an indexed list of systems in the handset– built by an operator – a definition of systems a mobile can access– is not accessible to the user

• The PRL comprises two Tables:– The Acquisition Table– The System Table

• The Acquisition Table contains:– An Indexed list of RF channels to search.– Each entry describes the RF environment of a particular area.

• The System Table contains:– An Indexed list of Systems, keyed by (SID, NID) pairs. – Each entry refers to a specific RF environment– Each system belongs to a geographical area– Relative Priority can be specified– Roaming display behavior can be specified– Negative (prohibited) systems can also be specified

• Preferring one system over another– Preferences can exist within Geographic areas– An operator can specify preferences on which networks to

access

Conceptual Representation of a PRL

Geo 4Geo 4 Geo 3Geo 3 Geo 2Geo 2

Carrier - System

(SID, NID)

Selection Pref

Roaming Indicator

Acquisition Index

SID/NID First off 0SID/NID Second on 1SID/NID Second on 2SID/NID Third flashing 4

Permitted Systems

Carrier - System

SID/NID

SID/NIDSID/NID

Forbidden Systems

Geo 1Geo 1

Acquisition Table

INDEX Network TypeChannels/

Block

0 Cellular CDMA (Standard Channels) B1 Cellular CDMA (Standard Channels) A2 Cellular Analog A3 Cellular Analog B4 PCS CDMA (Using Channels) 425

5 PCS CDMA (Using Blocks) F

System Table

Acquisition Table

PRL review

EV-DO UpdateMarch 2005

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Important features of extended PRL format (IS-683-C)

• New Acquisition Record Type for EV-DO/HRPD

• New System Record for EV-DO/HRPD Systems

– Uses Subnet instead of SID/NID

• New field in System Records (ASSOCIATION_TAG) associate 1xRTT System Records with EV-DO records

EV-DO UpdateMarch 2005

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Basic Flow of Hybrid System Selection

• Acquisition table is used to acquire system

• EV-DO acquisition records are ignored until a 1xRTT system is acquired

• System table is used to find highest priority system available in GEO

• If the system acquired has a system whose record has an association tag for an EV-DO system, then the system will search for it and acquire it

IMPORTANT POINT: The prioritization of 1xRTT system determines whether or not EV-DO systems will be acquired depending on which ones have association tags to EV-DO system

EV-DO UpdateMarch 2005

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My Contact Info:

Bryan Cook

Qualcomm Engineering Services

408-557-3516

bcook@qualcomm.com