International RoamingBY:Rawand Dlshad Jaf

IREG Engineer

Purpose of the presentation• To Answer questions:• ‘'What is Roaming?’’.• Why we have ‘Roaming Agreements?• How dose International Roaming

work?• How do I get billed for making and

receiving calls?

What is Roaming?(1/1)

• “Roaming is defined as the ability for wireless customers to automatically make and receive voice calls, send and receive data, or access other services when travelling outside the geographical coverage area of their own home network, by means of using a visited network.”

simplified

• Service by a mobile network operator enabling access to its network for subscribers to a foreign

mobile network for making and receiving calls

1992First international roaming

agreement between

Telecom Finland and Vodafone in UK.

Roaming Agreement(1/1)

• In order that a subscriber is able to "latch" on to a visited network, a roaming agreement needs to be in place between the visited network and the home network. This agreement is established after a series of testing processes called IREG (International Roaming Expert Group) and TADIG (Transferred Account Data Interchange Group). While the IREG testing is to test the proper functioning of the established communication links that performed by IREG Engineers , the TADIG testing is to check the billability of the calls.

Roaming Services

• The service a roamer enjoys in a visited network depends on three factors:

mobile station (MS) capabilities, the agreed list of services in the roaming agreement, and the subscription level.

Commercially available handsets generally support the following networkcapabilities:

■ GSM

■ GSM + GPRS

■ GSM + GPRS + 3G

The technical aspects of international mobile roaming • The technical process of a roaming call is called

‘routing’.• To understand the routing of international mobile call,

SMS and data roaming services, a basic understanding of the signaling behind mobile phone calls is needed. A mobile phone call requires two different types of signals: the ‘control’ signal and the ‘voice’ signal. The control signal carries the network data of the call. This signal allows for the mobile phone to be identified, and records the destination, length and geographical location of the call. The voice signal carries the actual voice, SMS or data message.

•

How dose International Roaming work?(10/1)

The details of the roaming process differ among types of cellular networks, but in general, the process resembles the following:

1. When the mobile device is turned on or is transferred via a handover to the network, this new "visited" network sees the device, notices that it is not registered with its own system, and attempts to identify its home network. If there is no roaming agreement between the two networks, maintenance of service is impossible, and service is denied by the visited network.

How dose International Roaming work? (10/2)

2- The visited network contacts the home network and requests service information (including whether or not the mobile should be allowed to roam) about the roaming device using the IMSI number.

3- If successful, the visited network begins to maintain a temporary subscriber record for the device. Likewise, the home network updates its information to indicate that the mobile is on the host network so that any information sent to that device can be correctly routed, and here location update process complete (LU).

HLR

MSC/VLR

IMSI

418 05

Is roaming allowed?

Copy of the HLR Profile (data)

willbe stored in Stock. VLR

Roamer Location Update (10/3)

Signaling

Calling home: how does it work? (10/4)

• If you are calling back home, then the visited operator analyses the dialed number , and decides how best to route the call and the call will be routing to home through a third operator called ‘carrier or international transit’ .

• Remember, when you call home or any other country, you have to type in the international access code and the correct country code along with the telephone number, omitting the leading zero.

• For example, to dial the IRAQ mobile number 0770 XXX XXXX from another country, you dial +964 770 XXX XXXX. If you are calling a landline, you may need to include an area code.

Calling home: how does it work? (10/5)

Receiving calls: how does it work? (10/6)

• When someone calls you the call will be routed to the operator whose network you are using in the visited country (How?)

Receiving calls: how does it work? (10/7)

• If you remember when the Roamer try to make Location Update the visit network MSC/ VLR (Mobile Switch center/Visitor location register) will contacts the home network HLR (Home location register) through GMSC (gate way MSC) and requests service information Likewise, the home network HLR updates its information (address of the host VLR) to indicate that the mobile is on the Visit network so that any Call or data can be correctly routed to the roamer.

• Don't forget; all international signaling between two operators transferring by the carrier.

Receiving calls: how does it work? (10/8)

HLRGWMSC

MSISDN

0770…

MSC/VLR

Originating Leg

Roaming Call Forwarding Leg

SignalingVoice

Receiving Call from another Roamer? (10/9)

When a Aisacell outbound Roamer -A- (let say in UK) calling another Asiacell outbound Roamer roamer –B- in another country (let say in USA) the call flow will be :

• A will dial B number with (+964 770 XXX XXXX) and the call will be routed through host GMSC to Asiacell in IRAQ and after that our GMSC will asking the location of B number from the home HLR and it will know that B is roaming in USA so the call will forward to USA (routed again) through asiacell and transferring be the carrier.

Receiving Call from another Roamer? (10/10)

HLRGWMSC

MSC/VLRA

MSC/VLRB

MSISDN+964 770….

Roaming CallForwarding Leg

SignalingVoice

How do I get billed for making and receiving calls?(2/1)

• When you use your phone while roaming (both making and receiving calls), the visited operator will keep a record of your calls. It will send these records, along with the corresponding charges, to your home operator.

Your home operator will aggregate these call charges, and reflect them in your next bill. All charges will appear in your home currency - your home operator will convert the foreign operator charges for you automatically.

It can take some time for the call charges to be sent to your home operator by the visited operator.

How do I get billed for making and receiving calls?(2/2)

•Thank you for you timePlease don’t hesitate to contact me if you need any

more information

www.rawand.ali@asiacell.com

Kirkuk region

IREG Eng