Telecom Roaming Overview

Telecom Roaming Overview

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Objective

Roaming Overview

Entities Related to Roaming Service

Home Network & Visited Network

National, International, Inter-standard Roaming

Inbound & Outbound Roaming

Roaming Scenario’s

Benefit of GSM technology in Roaming

Jargon

Roaming Overview

Roaming is an ability to access mobile data and voice services even if subscriber is outside the coverage area of HOME Network.

It is possible via using VISITED Network services.

To provide roaming facility to subscribers, operators should have roaming agreement with the other operators in different places.

Roaming Overview …

Cell phone

Switch

City 2 (Visited Area)

Subscriber is on

Roaming.

City 1 (Home Area)

Subscriber’s own

area where they are

using its own

providers services

Switch

Cell phone

Home Operator -

Hutch Area

Visited Operator’s

Area (Roaming

Partner of Hutch)

MSC

Hutch Network

Infrastructure

Hutch

Subscriber

Roaming

Agreement

Present between

Hutch and other

Operators

Hutch Subscriber

but using other

operator services

for Roaming

purpose

MSC

Other operators

Network

Infrastructure

Entities Related to Roaming Service

Home Network (HPMN) - Coverage area of subscribers own telecom operator.

Visited Network (VPMN) – Coverage area of another operator which is providing telecom network access to home operator subscriber.

Clearing House – Entity which is a mediator between home and visitor operator to interchange their data in specified format.

Roaming Agreement – To provide roaming facility both the operators (Home and Visitor) should have agreement to use each others network infrastructure.

Data Clearing – Facility to validate, filter and clear the data from one operator to another operator.

Home Network & Visited Network

Cell phone

Home Network

Visited Network

Cell phoneCity

Operator1 suscriber in

Operator1 coverage area

Operator1 suscriber in

Operator2 coverage area

NE

NE

Clearing House

Operator1 & Operator2 have

Roaming Aggrement

Roaming Data

from Operator2

for Operator1

Roaming Data

from Clearing

house to

Operator1

National, International, Inter-standard Roaming

National Roaming – If visited Network is in the same country, it is called National Roaming.

International Roaming – If the visited Network is in the different country, It is called international or Global Roaming.

Inter-standard roaming - If the visited network operates on a different technical standard than the home network, this is known as Inter-standard roaming.

Inbound & Outbound RoamingAssuming – Airtel as a home operator

Inbound Roaming – Customers of other operator roaming in Airtel area and using Airtel infrastructure then this activity is called inbound roaming. Only those customers can roam in Airtel network whose operator has Inbound Roaming agreement with Airtel.

Outbound Roaming – Outbound Roaming refers to Airtel customers roaming in network of other operators area. Customers of Airtel can roam in network of other operators with whom Airtel has Outbound Roaming agreement.


Reciever

Other Operators NE


Subscriber is on

Roaming.

City 1 (Home Area)

Subscriber’s own

area where they are

using its own

providers services

Hutch NE

Caller

Home Operator -

Hutch Area


Area (Roaming

Partner of Hutch)

HUTCH MSC

Hutch Network

Infrastructure

Roaming

Agreement

Present between

Hutch and other

Operators

Hutch Subscriber

but using other

operator services

for Roaming

purpose

MSC

Other operators

Network

Infrastructure

Caller calling to

Hutch Roamer

Scenario 1 - When Roamer receives calls while on roaming, all his calls will reach the MSC of his Home Network in the first instance. He will be traced in his visited network and the calls are therefore forwarded there.


Caller - Hutch Roamer

Other Operators NE


Subscriber is on

Roaming.

City 1 (Home Area)

Subscriber’s own

area where they are

using its own

providers services

Hutch NE

Receiver of Hutch

Home Operator -

Hutch Area


Area (Roaming

Partner of Hutch)

HUTCH MSC

Hutch Network

Infrastructure

Roaming

Agreement

Present between

Hutch and other

Operators

Hutch Subscriber

but using other

operator services

for Roaming

purpose

MSC

Other operators

Network

Infrastructure

Hutch User

Receiving Hutch

Roamer Call

Scenario 2- When roamer makes calls to his Home Network (HPLMN), he obviously knows that he is temporarily out of his home network and thus his calls are routed through his temporary home network ie. visited network (VPLMN).



Other Operators NE


Subscriber is on

Roaming.

City 1 (Home Area)

Subscriber’s own

area where they are

using its own

providers services

Hutch NE

Reciever

Home Operator -

Hutch Area


Area (Roaming

Partner of Hutch)

HUTCH MSC

Hutch Network

Infrastructure

Roaming

Agreement

Present between

Hutch and other

Operators

Hutch Subscriber

but using other

operator services

for Roaming

purpose

MSC

Other operators

Network

Infrastructure

User Receiving

Hutch Roamer

Call

Scenario 3-When he makes calls within his visiting network which is his temporary home network, his calls are routed within that without being routed through his home network (HPLMN).



Other Operators NE


Subscriber is on

Roaming.

City 1 (Home Area)

Subscriber’s own

area where they are

using its own

providers services

Hutch NE

Reciever

Home Operator -

Hutch Area


Area (Roaming

Partner of Hutch)

HUTCH MSC

Hutch Network

Infrastructure

Roaming Agreement

Present between

Hutch and other

Operators

Hutch Subscriber

but using other

operator services

for Roaming

purpose

MSC

Other operators

Network

Infrastructure

City3 User

Receiving Hutch

Roamer Call

Roaming Agreement

Present between City2

& City3 Operators

City 3 (Receiver

Area)

City3 Operators NE

MSC

Scenario 4 - When he is making calls to networks other than his home network or the temporary home network, his calls are routed through the temporary home network only.

Benefit of GSM technology in Roaming

GSM Roaming, which involves roaming between GSM networks, offers the convenience of a single number, a single bill and a single phone with worldwide access to over 191 countries.

The convenience of GSM Roaming has been a key driver behind the global success of the GSM Platform.

Jargon

PLMN - Public Land Mobile Network.

HPLMN - Home Public Land Mobile Network (Home Network ie. say the state of West Bengal)

VPLMN - Visited Public Land Mobile Network (Visited Network - say the state where roaming - outside West Bengal)

Notional TAX - The Trunk Auto Exchange of a particular State (say for West Bengal it is Asansol; for Orissa it is Cuttack and so on). Each state has a Level 1 TAX through which the calls for & from other states pass.

PSTN Phone - Public Switched Telephone Network ie. a Landline Phone.

PSTN Charges - The fixed line phone charges either Local Call Charges or STD Charges.

Air Time - The duration of the call ie. during which time the call is there in the Air.

POI - Point of Interconnect - This is where the mobile network is connected to the PSTN.

SA - Service Area - The area served by a particular operator. Usual a state boundary.

MSC - Mobile Switching Center ie. Mobile Exchange.

BSC - Base Station Controller - It is an interface between the MSC on the one side and the BTS on the other.

BTS - Base Transceiver Stations (Towers)

Billing and Accounting for Roaming Group (BARG) - A subgroup of the GSM Association that focuses on the financial, administrative, and procedural issues related to roaming (visiting) customers.

THANKS

Education

Telecom Roaming Overview