ICR_1.pdf

Soc Classification level ICR / vithomas / 30-JUL-20081 © Nokia Siemens Networks

Intra Circle RoamingVodafone – Idea Cellular


Concept

Benefits to Operator


Intra Circle Roaming

Intra Circle Roaming is a service which enables a mobile station of a given public land mobile network (PLMN) to obtain services from another PLMN in the same country on a location area basis, with automatic return to the home PLMN when this is possible.

The main functional property of the Intra Circle Roaming feature in the network subsystem is that it can prevent location updates in certain areas (groups of location areas) by subscribers from other networks, while allowing it in other parts of the network.

Home

PLMN

LA1

LA2

LA3

XLA4

X

Concept


Benefits for the operator

Intra Circle Roaming is often implemented by the rules and conditions set by the National Regulatory body (TRAI). However, there are many benefits an operator can gain from implementing Intra Circle Roaming in GSM 900/1800 networks.

The benefits include:

• larger coverage area

• faster network roll-out

• cost savings.

The Intra Circle Roaming feature allows the operator to differentiate, in the

operator's national network, between one area where roaming from

neighboring networks is allowed, and another where it is denied.

Benefits to Operator


Initial Stage

Initially when a new Operator (VFE) tries to expand the network the scenario could be as should below

Serving Operator

VodafoneLA1

LA2

LA2

LA2

LA2

LA2

LA2

LA2

LA2

LA1

LA1 = Roaming Not Allowed

LA2 = Roaming Allowed


Intermediate StageConsider that LA1 is the Original LAC of this area

Initially the Serving Operator creates a LA2 which is a replica of LA1 but allows Intra Circle Roaming

He adds all the BTS which requires Intra Circle Roaming into this LAC LA2

All the other BTS are still with LA1 which does not support Intra Circle Roaming

After a period of time ( say 3 months) , when the coverage increases then the cell and reduced from LAC LA2 and added onto LAC LA1 as shown in the figure below

Serving Operator

VodafoneLA1

LA2

LA2

LA2

LA2

LA2

LA2

LA2

LA2

LA1

LA1

LA1

LA1

LA1

LA1 = Roaming Not Allowed

LA2 = Roaming Allowed


Final Stage

Till a day when the riding network has full coverage and Intra Circle Roaming is not requiredThen the dummy LAC LA2 which was created is deleted

Serving Operator

VodafoneLA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1


ScenariosScenariosScenariosScenarios

Scenario I : New Entrant

Scenario II: Two incumbent Operators

Scenario III: Scattered Network, difficult Terrain

Scenario IV: Region of common coverage


Scenario I – New Entrant (Example :: Idea in Chennai and VFE in MP)

Situation•Very Less Radio Coverage in the Region for new operator•Coverage Area is a part of common coverage•Solution•Intra Circle Roaming is an ideal solution for faster rollout•The new Entrant slowly build up the network while its subscribers enjoy complete coverage of the region from day One

Vodafone

Idea

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1LA1

LA1

LA1


Scenario II – Two Incumbent Operators (Maharashtra & AP)

Situation•All Densely Populated regions are areas of Common Coverage•There are certain scantly populated regions where Vodafone has Coverage•There are certain scantly populated regions where IDEA has CoverageSolution•Intra Circle Roaming is an ideal solution for providing complete coverage in the region without major investment•Based on the traffic profile each operator can decide whether to put a site or not•Long term CAPEX and OPEX savings

Vodafone only Coverage Area

Idea only Coverage Area

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1LA1

LA1

LA1Common coverage Area


Scenario III: Scattered Network – Difficult Terrain (Konkan region, Bihar, East India)Situation•All Densely Populated areas are area of Common Coverage•There are certain scantly populated regions where Vodafone has Coverage but is scattered across region•There are certain scantly populated regions where Operator 2 has Coverage but is scattered across regionSolution•Intra Circle Roaming is an ideal solution for CAPEX and OPEX saving only•Since the areas are scattered, the regions where a site is not planned to come up in a years time has to be considered for Intra Circle Roaming•Ideal solution for difficult terrain where there are small towns in valleys , dense vegetations, desert etc

Operator 2 covered towns

Vodafone covered small town

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1LA1

LA1


LA1LA1

LA1

LA1

LA1


Scenario IV: Region of Common Coverage

Situation•Both Operators have same region of coverage but there are coverage holes due to many factors like tall buildings, site has no power etc•Congestion is pretty high due to more number of subscribers but has no solution to de-congestSolution•Intra Circle Roaming could be a solution but its not recommended for Serving operator as the signaling load could be very high•On top if Intra PLMN handover is defined then CDR re-conciliation would be very complex task

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1

LA1 LA1

LA1

LA1LA1

LA1



Location updatingIn a case where the mobile station's PLMN information is defined as "home country and visitor PLMN”, the national roaming checking’s apply. "National Roaming Allowed" parameter is checked in this case and it contains a list of allowed Mobile Network Codes (MNCs) per each location area.

If the MNC of the MS appears in the list, the location update is accepted; if not, the location update is rejected because of the Intra Circle Roaming restriction.

The Intra Circle Roaming restriction indication to the MS depends on the MS's supported GSM specification phase. This is because the GSM Phase 1 specification did not include Intra Circle Roaming definitions. The MS indicates its phase in the MS_classmarks revision level field. If the revision level indicates Phase 1 behaviour, the cause 'location area not allowed' is returned to the MS; if it indicates Phase 2, the returned cause is 'national roaming not allowed in this location area'.

If the location updating is rejected with the cause ‘National Roaming not allowed', the MS starts the initial access procedure. However, since the cause 'location area not allowed' has not been intended to be used in this context, some of the Phase 1 mobile stations may also behave in an unpredictable way. It is therefore recommended that the behaviour of different mobile stations is checked by the operator before taking this feature into use.

The handling of user information in the network depends on the update status of the subscriber in the VLR at the moment when the location updating of the MS was rejected.

There are two different cases:

MS known to the VLR

This is a case in which Intra Circle Roaming was still allowed at the time when the previous location updating occurred. Later, when location updating is attempted again, it is not allowed any more, and Intra Circle Roaming restriction thus applies. In this case the user status in the VLR is defined so that the originated attempts are not allowed.

MS not known in the VLRIn this case the user information is not retrieved from the HLR.


CALL Handling(a) Voice Calls terminating to VFE Customers roaming on Operator’s Mobile Network will be handled in the same manner as terminating calls to international Roaming Customers Specifically, the interrogating VFE’s GMSC will obtain through VFE’s home location register the Mobile Subscriber Roaming Number (MSRN) provided by Operator’s visiting MSC. MSRN ranges are part of the geographic number ranges and will be routed accordingly.

(b) Voice Calls originated by VFE mobile Customers roaming on Operator’s GSM Network will be handled in the same manner as Calls originated by Operator Customers. This includes Calls made to VFE’s Customers which will be routed to VFE’s GMSC regardless of whether or not the Called Party is roaming on Operator’s Mobile Network at the time of the Call.

(c) Standard roaming signaling protocols will apply, namely for Location Update, Mobile Originating Calls (MOC), Mobile Terminating Calls (MTC) and supplementary services.

(d) In the case of prepaid roaming VFE customers, Intelligent Network (IN) signaling based on CAMEL V2 (Customized Application Mobile Enhanced Logic Version 2) will be adopted based on the relevant triggering mechanism

(e) In the case of a VFE Customer with a Call in progress moving out of VFE’s coverage area, the Call will not be handed over to Operator and will be dropped. (If handover is required its inter PLMN handover where the boundaries have to be defined with neighbors which is difficult)


GPRS For GPRS roaming when the subscriber is roaming in a serving

network, the Location update is made with the SGSN.

Internet

Flexi ISNBSS

Gb/Fr

Gb/IP SGSN

NSS

PLMN 2 Data network

USER DATA PATH

Gr

Flexi ISNBSS

Gb/Fr

Gb/IP SGSN

NSS

PLMN 1 Data Network

Gr

Subs from PLMN1

SS7 network

GRX

BG

BG


Prepaid

Prepaid subscribers are treated the same way like the postpaid subscribers, but the call handling is different as the IDP is directly sent from the VPLMN to the SCP, based on the GT updated while making location update.

Triggering mechanisms for Roaming prepaid Customers

The following are the trigger mechanisms for Roaming prepaid Customers

Voice

CAMEL Phase 2. SCP GT is passed During Insert Subscriber Data (LOC UPD)

SMS

If CAP3 is used for roaming, then the charging is online and hence not much of an issue

This is a scenario for balance hold before delivery, VFE specific scenario needs to be checked

MMS

If offline charging is in use then the mechanism for roaming needs to be checked. It could have impact on roaming scenarios


Dropped calls Scenario

Using Visitor Roaming Capability, VFE anticipates that active Calls will be dropped when a VFE mobile Customer transits the roaming boundary as per the following conditions:

(a) there will not be seamless Call Roaming

(b) the Call drop will occur when VFI mobile Customers move from VFI covered areas to an IDEA-only covered area

(c) the Call will not drop when VFI mobile Customers move from IDEA-only covered area to VFI covered area.

Note:: In this ex VFE = RIDER & IDEA = SERVING Network


Other Issues

Vodafone/IDEA Logo Display

As the dependency is on the handset, Network Broadcast would be done as usual

International Roaming

This feature has no impact on National or International Roaming. However exclusive bi-lateral agreements of each network will not be binding for serving network, and the IR / NR customer may be deprived of services

Access to Short Code Services

When VFI mobile Customers are roaming onto the Operator Mobile Network they should be able to continue using the VFI dialing plan as per the attached short code services. In particular, there will be access to the VFI short code services (e.g. Voicemail, pre-pay recharge services) using the same dialing format for the attached short code services as when the MS is directly connected to the VFI network.

Short CodesUsage111 123

** USSD codes need not be agreed as it points to HLR directly but the information needs to be shared


Billing

Customer billing PROTOCOLS FOR INTRA CIRCLE ROAMING (a) Operator will be responsible for generating the CDRs for Intra Circle Roaming Calls.

(b) The Parties agree to interchange of billing data using TAP3 protocols. The frequency within which TAP files are exchanged is to be agreed between Parties, but in any event must not be more than once every 24 hour period.

For Prepaid its real time charging hence no issues


Trial ScenarioIdentify a Cell Site which does not have coverage for IDEAMSS Side• Create new LAC XYZ which allows Roaming• Add Cell ID not having IDEA coverage into this LAC• Create Roaming definitions• Create Digit Analysis for IDEA• Open GT for SCP • Configurations for CAMEL Roaming follow process of IR 24

RF Side• Change the LAC of this site to new LAC XYZ• Add the Neighbors considering this change in LAC• Change the RAC of this site to RAC ABC

IN Side IDEACreate this PLMN in SCP and prepare the tariff table entries

SGSN sideCreate entry for this RAC and allow roaming for IDEAGGSN & Firewall configurations required for V-SGSN


Identified Candidates for Trial

15-Feb-08VodafoneAurangabadNewTherla repTherla repBidBSC49BEED836

29-May-08VodafoneAurangabadNewDongarkinhiDongarkinhiBidBSC49BEED5346

Date of CommisioningOwnerCluster

New Town/ExistingSiteNameTown NameDISTRICTBSC NameSite ID

Maharashtra

Where there is VFE coverage but no IDEA coverage


Share of Responsibilities(a) Operator will be responsible for the following aspects of the Intra Circle Roaming Service: (Prov ider )• Radio network elements including the BTS (Base Transceiver Station) and BSC (Base Station Controller)

• Network Quality of Service

• VMSC (Visited Mobile Switching Centre) and VLR (Visitor Location Register)

• Lawful call interception, including where a warrant for call interception is served on VFE, in which case Operator is to provide call interception services upon being notified by VFE that VFE has been served a warrant requiring call interception; and in accordance with the same procedures that Operator would apply if the warrant was directly served on it

• Generation of CDRs for end user billing; and

• Inter-operator billing

(b) VFE will be responsible for the following issue s related to the Intra Circle Roaming Service: (Rid er)• Billing and collection of charges from its Customers

• Customer service, provisioning, complaint and fraud handling

• Network Quality of service

• HLR (Home Location Register)• Authentication

• Prepaid system

• Voice mail system

• SIM card management

• MNC (Mobile Network Code)• IMSI (International Mobile Subscriber Identity)

• MSISDN (Mobile Station ISDN)


Some known Issues

• Increase in the inter VLR Location update due to the increased number of LAC for serving operator

• Frequent call drops at boundary locations• Problems of abnormal behaviour of GSM Phase 1 only supported

handsets• Restriction of certain services while in VPLMN• Development on IN Platforms for seamless support of services• Modifications in Mediation systems to consider the tariff plan while

customer is roaming in VPLMN• Miscommunication of subscriber figures from the Serving Operator• Misuse of IN services in VPLMN• Difficulty in offline charging of VAS services (GPRS / SMS / Content)• Difficulty in fraud management


Conclusion

Although there are few third party solutions available in market, but LAC based roaming has be the most effective rollout feature which has been deployed world wide in many projects with promising results. References can be provided on request, as its customer specific.


FAQ1) Limited Roaming – Allow Voice & Data calls Where we do not have coverage. Coverage will increase wi th time.

This is the feature of LAC based roaming explained in section 3,4,5

2) In a common coverage area Subscriber to remain o n Home Network. They should not be able to latch on to partner network.

Also included in the feature

3) Granularity – Cell Level

Explained in section 3.3

4) VF Logo to be displayed while customer is roamin g.

This the responsibility of the Serving operator

5) Type of Customer, Local, National Roamer & Inter national Roaming

For National and International roaming, the agreement will not be applicable in the Roaming LAC

For eg >> If VF UK has International roaming agreement with VF India, but no roaming agreement with IDEA, then in such cases VF customers will be able to use this service in Regions where IDEA is providing Intra Circle Roaming for VFI

Similarly National Roaming customer of VFI which does not have tie ups with IDEA will not be able to use this service

6) VAS short codes & VAS Applications to be support ed when roaming

These short codes have to be shared with the serving operator, generally the operator accepts the short codes upto 10, USSD codes may not be defined but has to shared as a part of information only

7) Business Logic applied in the home network shoul d be applicable in VPLMN.eg post paid credit limit,

Scenario’s which are applicable in Roaming will be applicable, but the exchange of TAP files has to happen at a faster rate as compared to International Roaming, All billing requirements and fraud management mechanism has to be agreed with the serving operator


FAQ8) Minimal Impact to customer

The customer will have similar experiences like in roaming scenarios, VAS services which are not applicable in roaming will not work here as well. But more VAS services can be provided after thorough testing with the serving operator

9) Impact on Network.

When VF is a Riding Network, then there will be minimal impact. If VFI is a serving operator then in such scenarios, there is load on the network. Especially signaling load will increase if the LAC’s and cell groupings are not planned with respect to the movement of the home subscribers

10) Billing system should support Inter PLMN LAC ba sed roaming

Generally Inter PLMN handover is avoided to reduce the problems related to billing, as the CDR is generated in both networks for call which is generated in one network but terminated in the other

11) IOT with other Vendor.

IOT is required is required for VAS and Prepaid services only, if the network is already compliant with IR 21, IR 32 etc then IOT for voice services are not mandatory

12) Possibility of including a third intra-circle r oaming partner.

For a riding network it can select 2 or 3 operators based on the coverage in a rural region, but for a serving network its recommended to have not more than one operator to avoid the signaling load on MSS / HLR

13) Minimal Dependency on roaming partner.

Billing information, Fraud management , Lawful Interception the riding network has to rely on the serving operator

14) All regulatory requirements need to be made eg, call routing ,IUC, spectrum issues related to capac ity

The serving operator generally has issues related to NLD , ILD traffic and these calls have to be routed back to the HPLMN. If its agreed in the initial stages then it will go on as in case of the national roaming scenario

15) No charge on IC calls when roaming.

The serving operator will charge for all calls, it has to be taken care in the Mediation Dept and SCP to handle such scenarios


Network ID

(a) When VFI mobile Customers are roaming on the Operator Mobile Network, the mobile device of the VFI mobile Customer will display the following:(i) on a mobile device with a 2 line display, the name of the Operator Network as defined by the mobile device (e.g. Operator) on the upper line and display ‘VF India’ on the lower line; and(ii) on a mobile device with a 1 line display, the mobile device will display ‘Vodafone-Operator’(b) Operator must not send a welcome SMS or MMS to a VFI mobile Customer that is roaming on the Operator Mobile Network (This has to be intimated to the Serving Operator in advance, as the tapping server would be sending sms to any in-roamer, this requires some development at the VAS vendor end)


Network ID

Should Network ID be displayed?Benefits::Subscriber is aware that he is roaming and hence able to report problems when roaming in X-Operator NetworkVF customers can detect easily if the X-Operator is using features like eMLPP to provide better service to his own subscribersEg>> In UAE the TRA has defined toll-free numbers for subscribers of Riding network to report problems when roaming in the network of the Serving Operator. Whenever the customers report problems like congestions or services not allowed, they immediately report the problem on the Toll Free numberDisadvantages::Subscriber is always aware that he is riding on X-Operators NetworkPeople staying in boundary locations will experience call drops and they will have more chances of churning to the serving operator

Note :: The feature in use on the NSN side is called Network Identity and Time Zone, this is similar the feature used by other vendors as well. The feature sends the Network Identity to the MS but its upto the handset to display the broadcast name, generally most of the handsets below s60 series or the ones older than 3 years tend to take the Network name from its handset list and thus over-riding the information coming from the Network broadcast

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