cdg workshop prl enhancements for international ... workshop prl enhancements for international...

QUALCOMM Engineering Services Group © 2004 QUALCOMM Incorporated

CDG Workshop

PRL Enhancements for International Roaming

Andrew [email protected]

February 2004

CDG PRL Enhancement Workshop

Andrew HunterQUALCOMM Engineering Services Group © 2004 QUALCOMM Incorporated

Overview

• Identification of CDMA Networks & PRLs

• CDG PRL Enhancements for Roaming

• Implementing PRL Enhancements– Infrastructure Capability– Handset Capability– Operator Activities

• Acquiring MCC and IMSI_11_12• Infrastructure Configuration• Technical Data Sheet Exchange• PRL Generation• Handset Configuration

February 2004



Identification of a CDMA network

• Every CDMA system – Operates on a particular frequency or

CDMA channel

• Every CDMA system is uniquely identified by the combination of

– System Identification Code (SID)– Network Identification Code (NID)– Radio Frequency

• Every CDMA system broadcasts its– Mobile Country Code (MCC) – Mobile Network Code (MNC aka

IMSI_11_12)

• Every CDMA base station broadcasts its system and network identities in system overhead messages

The Market

Regionsof the market

Operator A’s implementation

of the market

Operator B’s implementation

of the market

February 2004



What is a Preferred Roaming List (PRL)?• The PRL is :

– an operator supplied list systems in the handset that defines the systems a mobile can access

• An Acquisition Table contains:– An indexed list of RF channels to search– Each entry describes the RF environment of

a particular area

• A System Table contains:– A list of system descriptions– keyed by (SID, NID) pairs & [Acq Idx]– Each entry is part of a geographical area

(GEO)– Access to systems can also be blocked

• 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 - SystemSID/NID

SID/NIDSID/NID

Forbidden Systems

Geo 1Geo 1

Acquisition Table

INDEX Network Type Channels/Block

0 Cellular CDMA (Standard Channels) B1 Cellular CDMA (Standard Channels) A2 Cellular Analog A3 Cellular Analog B4 PCS CDMA (Using Channels) 4255 PCS CDMA (Using Blocks) F

System Table

Acquisition Table

February 2004



Problem Statement

• A SID normally cover the area of a city or large town

• A NID is a subset of a SID (different rating areas, toll areas, private networks, MSC boundaries, etc.)

• National wireless carriers’ networks may cover a large number ofSIDs (tens or hundreds)

• When international roaming is required PRLs become significantlylarger due to the inclusion of the roaming partners’ SIDs

– More memory required in the handset of R-UIM– Larger PRL download times (OTA)– Difficult to keep updated in Handsets

February 2004



CDG Resolution for PRL Enhancement

• Mobile Country Codes and Mobile Network Codes (Operators)– Operators obtain and use MCCs and MNCs (IMSI_11_12) for their CDMA

network

• Use existing broadcast mechanisms for this information (Infrastructure)– Ensuring valid information is being broadcast in the Extended System

Parameters message• MCC is mandatory• IMSI_11_12 is mandatory

• Enhanced PRL system table entry (PRL)– Allows the description of a system by

• SID/NID• MCC/MNC (IMSI_11_12)

• Enhanced system determination (Handset)– use the MCC/MNC (IMSI_11_12) scheme in system selection

• Backward compatibility (Existing Infrastructure & Handsets)– Presence of a MCC/MNC (IMSI_11_12) entry in the PRL will not ‘break’ any

• existing handset system determination• existing PRL management mechanisms

February 2004



Identifying a system

• Every CDMA system broadcasts in system parameters messages

– System Identification (SID)– Network Identification (NID)– Mobile Country Code (MCC)– IMSI_11_12 (akin to Mobile Network

Code - MNC

• Currently the CDMA granularity of roaming control is the SID/NID pair

– One description of a particular market within the carriers network as chosen by the carrier

– Provides good control for the carrier of how to describe the network

• Now the CDMA operator may describe their network BOTH ways:

– Using the granularity of SID/NID for its own users and other roaming partners as needed

– Using the MCC + IMSI_11_12 granularity for roaming partner PRLs that do not require SID/NID information

– Both can be used in combination

SID & /NIDMCC & IMSI_11_12

SID/NIDMCC/IMSI_11_12

SID/NIDMCC/IMSI_11_12

February 2004



PRL enhancements: how they work

• PRL– Can describe a system by

• SID/NID • MCC/MNC

– Full backward compatibility is supported.

• System determination– updated system selection software to use the

enhanced format– Existing system selection will process enhanced

format as normal SID/NID entries

• Use of a valid MCC and IMSI_11_12– ITU issues MCCs – Each country administers allocation of Network

codes in the US the administrator is Telcordia (www.imsiadmin.org)

– CDMA air interfaces currently support the broadcast of a 2 digit MNC. (As in GSM)

• Configuring network to use these values in its broadcasts

– The network is currently broadcasting something –the manufacturer default if it has not be set by the operator

– Configuration with the real MCC/MNC values is required for the enhancements to work

BSC

Abis

System Parameters: {SID=8742, NID=65535}Extended System Parameters: {MCC=310, IMSI_11_12=10}

Carrier - System(SID, NID) or (MCC/MNC)

Selection Pref

Roaming Indicator

Acquisition Index

MCC/MCC=310,10 First ON 0MCC/MCC=310,42 Second ON 0

Permitted Systems

Geo: CountryXGeo: CountryX

System Table: Geo entries requires for CountryX

Handset view of the PRL enhancements Network view of the PRL Enhancements

CDMAroamer

MSC

BSC

CDMA/OTA

CSC

February 2004



Use of Existing Standards

• The resolution does not modify any CDMA standard.

• It describes a uniform method for populating and using existing data elements currently in use.

• Does not impose any requirements on the use or not of full-IMSI in the core network (ANSI-41).

• Describes an encoding convention to describe a system by its MCC and IMSI_11_12 in the SID and NID space of a PRL entry:

– MCC10 bits+ IMSI_11_127 bits = 17 bits– SID = 15 bits, NID = 16 bits– Use of NID for MCC9 bits+ IMSI_11_127 bits – Use of 2 special SIDs for MCC10 (values of 0 1nd 1)

• Used world wide• Not in use by any other operator

February 2004



Implementing the CDG Resolution

US Operator

Foreign Operator4

InfrastructureConfiguration

PRL Management

CDG

Network DataAdmin

ii

2 3

1

TDS

Handset Supplier

MSProgramming

MSProgramming

b

c

d

Enhanced PRL Roaming

e

i

Infrastructure Supplier

a

iii

Network Data

Admin

MCC/MNCAdministrator

(USA: Telcordia)

MCC(s)ITU

February 2004



CDG Coordination Roles

• IFAST And Special SIDs– IFAST has approved the following allocation 15904-15905

• Mobile Network Code Convention– Coordinate a proposal to Telcordia on allocation guidelines for

CDMA operators’ Mobile Network Codes

– Assist in other countries where an MNC usage convention may need to be adopted if required

February 2004



Infrastructure Suppliers Impact

• Support IMSI aspects on the over the air aspects of the system only

• MCC and IMSI_11_12 are sent in the Extended System Parameters Message by the base station

• Operators must be able to configure systems to broadcast their own MCC and IMSI_11_12

– Most are broadcasting something other than wildcards

– Many have manufacturer default values

• No migration to full IMSI in the ANSI-41 Core Network is required

1RESELECT_INCLUDED

3MAX_NUM_ALT_SO

8PACKET_ZONE_ID

6DROP_INTERCEPT

6ADD_INTERCEPT

6SOFT_SLOPE

8MIN_P_REV

8P_REV

1IMSI_T_SUPPORTED

3BCAST_INDEX

8 x TMSI_ZONE_LENTMSI_ZONE

4TMSI_ZONE_LEN

7IMSI_11_12

10MCC

2PREF_MSID_TYPE

1USE_TMSI

1DELETE_FOR_TMSI

6CONFIG_MSG_SEQ

PILOT_PN

Field

9

Length (bits)

February 2004



Handset Suppliers Impacts

• Existing handsets and existing System Selection implementations will not be ‘broken’ by encountering an ‘enhanced PRL’ entry

• System selection must be upgraded to understand system described in terms of MCC, IMSI_11_12

– New format MCC, IMSI_11_12 records will be ignored by existing system selection implementations.

• QCT chipsets will have this functionality later this year

• Complying with the new handset specs that operators will produce to require the PRL Enhancement

February 2004



System Parameters: {SID=8742, NID=65535}Extended System Parameters: {MCC=YYY, IMSI_11_12=xx}

[MCC, MNC]

Operator Implementation Aspects• Obtaining the valid MCC and IMSI_11_12

for their network(s)

• Configuring Infrastructure and verifying the broadcast of valid MCC and IMSI_11_12 values

• Informing roaming partners of MCC/IMSI_11_12 values in Technical Data Sheet (TDS) exchange

• Specifying the PRL Enhancement behavior in Handset specifications

• Building and distributing new PRLs with the more streamlined MCC/MNC entries

TDS

Handset Specification

[MCC, IMSI_11_12]

New PRLs

February 2004



PRL Enhancement Resolution - Benefits

• Provides a more efficient means to describe a network in a PRL– Knowledge of the use of SIDs and NIDs within a visited network becomes

optional– National wireless carriers’ networks may cover a large number of SIDs (tens or

hundreds)

• Requires no changes to existing standards– Existing messages/fields populated with appropriate data

• Does not require that full IMSI support be available in the core network (ANSI-41) for its implementation

• Allows for reduction in size of PRLs

• Allows international roaming partners to describe a greater number of roaming networks in the same PRL size

– More efficient use of memory in the handset of R-UIM– Reduced PRL download times (OTA)– Easier to ensure foreign partners’ information is current

QUALCOMM Engineering Services Group © 2004 QUALCOMM Incorporated

CDG Workshop

PRL Enhancements for International Roaming

Andrew [email protected]

cdg workshop prl enhancements for international ... workshop prl enhancements for international...

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