CDG Global Roaming Symposium PRL Enhancements for ...cdg.org/news/events/CDMASeminar/031211/9-Q-PRL... · Geo 1Geo 1 Acquisition Table INDEX Network Type Channels/ Block 0 Cellular

QUALCOMM Engineering Services Group© 2003 QUALCOMM Incorporated

CDG Global Roaming Symposium

PRL Enhancements for International Roaming

Andrew [email protected]

December, 2003


Andrew HunterQUALCOMM Engineering Services Group © 2003 QUALCOMM Incorporated

PRL Overview

• Identification of CDMA Networks

• How is the PRL used by the MS?

• PRL Enhancements for Roaming

December, 2003



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 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

December, 2003



What is a Preferred Roaming List (PRL)?

• The PRL is :– an indexed list of systems in the handset– built by an operator – a definition of systems a mobile can access– is fully described in IS-683.– 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 & [Acq Idx]– 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 - 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

December, 2003



What is the Preferred Roaming List (PRL) for?

• The PRL assists the mobile in the acquisition and system selection process

• Tells the mobile which systems are permitted and prohibited• It speeds up acquisition• Provides the flexibility to specify a “Roam” or “Not Roam”

condition on mobile’s display• Provides the operator flexibility in specifying mobile search

behavior in:– home market – roaming markets

• PRL standards allow for the description of– CDMA2000 1x, IS95 systems– 1x EV-DO systems– GSM systems

December, 2003



Where is the PRL and how does it get there?

• The PRL can be stored in either– NV-RAM – R-UIM

• An initial or default PRL would be loaded into the phone or R-UIM prior to distribution

• A new PRL can be loaded into the handset– At a customer service center using service

programming tools– Over the air using a OTASP (Over the Air Service

Provisioning - see IS-683)• Although PRL is defined in the OTASP specification,

OTASP is not required for PRL• OTASP facilitates ease of updates once handsets are in

customers hands as new roaming partners are added

December, 2003



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 of SIDs (tens or hundreds)

• When international roaming is required PRLs become significantly larger 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


Enhancements to the PRL for International roaming

The Proposal

December, 2003



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

• In CDMA the 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

• The Enhancement allows the CDMA operator to describe their network BOTH ways:

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

– Using the MCC + MNC (IMSI_11_12) granularity so roaming partner PRLs do not have to contain all the SID/NID information

SID & /NIDMCC & IMSI_11_12

SID/NIDMCC/IMSI_11_12

SID/NIDMCC/IMSI_11_12

December, 2003



What are the PRL Enhancements?

• Use of existing broadcast information– 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– Allows the description of a system by

• SID/NID• MCC/MNC (IMSI_11_12)

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

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

• existing handset system determination• existing PRL management mechanisms

December, 2003



PRL enhancements: how they work

• PRL– Has ability to describe a system by

• SID/NID • MCC/MNC

– Encoding such that full backward compatibility is achieved.

• System determination– To use the MCC/MNC format system

determination software must be updated.– If system determination is not updated and

PRL has MCC/MNC type entries they will appear as normal SID/NID entries

• Obtaining a MCC and MNC from the appropriate regulatory body

– For example, the US issuing agency 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

CDMAroamer

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

December, 2003



Base Station Requirements

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

• Updates and coordination to uniquely identify the operator via the MCC and IMSI_11_12

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)

December, 2003



Mobile Station Requirements

• The MCC and IMSI_11_12 in the SID/NID space:– 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)

• Assignment of two special SIDS from IFAST required– Used Operator wide– Not in use by any other operator

• To use this in the handset the system selection must be upgradedto 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.

December, 2003



Infrastructure Impact Investigations

• Lucent– No issue provided the infrastructure is beyond the software

release that supports full IMSI paging– Note this is only full IMSI on the OTA side NOT IS41

• Ericsson – No issue

• Nortel– Investigating

December, 2003



IFAST And Special SIDs

• IFAST has approved the following allocation

SID Range Qty Country Status

15904-15904 1 "Operator escape code '0' for TIA-683CDMA PRL" Application to be assigned

15905-15905 1 "Operator escape code '1' for TIA-683CDMA PRL" Application to be assigned

December, 2003



Progress…• IRT Proposal and White-paper for Review

• Discussion with carriers on feasibility

• Discussion with Infrastructure Vendors

• IFAST Special SIDs

• IRT Resolution for presentation to CDG Board

• CDG Board Approval

• Implement proposal in Handset software

• Approach Telcordia regarding MNC assignments for North America

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CDG Global Roaming Symposium PRL Enhancements for International Roaming

Andrew [email protected]

Documents

CDG Global Roaming Symposium PRL Enhancements for ...cdg.org/news/events/CDMASeminar/031211/9-Q-PRL... · Geo 1Geo 1 Acquisition Table INDEX Network Type Channels/ Block 0 Cellular