Sms Data Roaming Explained

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Mobile SMS and Data Roaming Explained


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Mobile SMS and data roaming explained

Roaming is the ability o customers to use their mobile

phones or other mobile devices outside the geographicalcoverage area provided by their normal network operator.When customers travel abroad and use their phones orlaptops whilst on a oreign (visited) network, this is knownas international roaming.

Sending and receiving SMS text messages whilst roamingabroad is called SMS roaming. Data roaming re ers to theuse o mobile data services whilst abroad. The most commonmobile data roaming services are:

MMS: Exchanging rich multimedia messages whileabroad with other customers on GSM/3G networks at home or abroad.

Push e-mail: Reading and replying to e-mails whileabroad, automatically pushed to mobile devices such as BlackBerries, personal digital assistants and sophisticated mobile phones.

Handset internet: Using mobile devices to access internetservices such as Web pages, Web 2.0 applications, music downloads and video streaming whilst abroad.

Mobile broadband: Connecting laptops via data cards orUSB dongles to the internet to provide access to commonapplications such as e-mail, Web browsers and companynetworks whilst abroad.

The usage o mobile data services is typically measured

in kilobytes (KB) and megabytes (MB), which re ers to thevolume of data transmitted for the service used. An e-mailwithout an attachment is typically between 1 and 50KB; anaverage web page can use several 100KBs or even moredepending on the number o graphical elements; and adownloaded song usually consumes 2 to 5MBs o data,depending on quality and length.

Clearly, the traf c volumes involved in one typical day of droaming can vary signi cantly depending on the type andusage intensity o the di erent data services.

Sending or receiving MMS or push e-mail typically usesseveral 10KBs per day unless large iles are attached.Sur ng the internet on a handset can incur data volumeso a ew 100KBs per day, but can also require several MBsif rich multimedia content such as MP3 songs and videostreams are downloaded. Mobile broadband volumes canquickly exceed 10MBs, as laptop-based applications such asdownloading presentations, pictures, music and videos aretypically very data-intensive.

As a result o the trend towards higher volumes o datadownloaded, operators have introduced innovative tari

packages, including fat rate daily bundles, which delivermuch lower prices per MB downloaded than were previouslyavailable.

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Operators offer a wide variety of data roaming tariffs catering for different data services and needs. Customers should get

know the array o tari s available on the market in order to select the package that best suits their needs. Most tari s all intoone o the categories shown in the ollowing table:

What tariffs for SMS and data roaming do operators offer?

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Type o tari

Standard roaming tari

Special roaming tari

Daily roaming bundles

Monthly roaming bundles

Description

The de ault tari a customer woulduse if he has not activated a speci croaming tari option. In this case,customers are typically chargedaccording to how many SMS or MMSthey have sent or how much data theyhave downloaded or uploaded

For a xed fee (typically monthly) thecustomer gets a lower data roamingtari (increasingly combined withdomestic data tari s)

A ee or a single day o dataroaming, which allows data roaming,up to a speci ed data usage limit, for a xed fee

A xed monthly fee, which includesa certain amount o data that can beused within each month while roaming

General suitability

These tari s are typically best suitedor occasional roaming with low

volume usage

These tari s are aimed at regular usewith low to average volume usage

These tari s are ideal or the occasionalroamer with a high data volumerequirement on particular days romtime to time

A regular roamer with high datavolumes would typically subscribe tosuch a tari

Tari s can be identical or all data services or di erent or the various data services. Some operators, or example, o er dailyroaming bundles for laptop connectivity and monthly bundles for push e-mail roaming. For SMS, most operators do not ch

or receiving an SMS while roaming, in much the same way as there is usually no charge or receiving an SMS at home.


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What happens when you receive an MMSwhile abroad? A friend sends an MMS to your mobile phone while you

are roaming. His operators network routes the MMS viainternational data transit to your home network.

Your home network sends an SMS notification to yourmobile phone abroad.

Once your mobile phone has acknowledged the SMSreceipt, the MMS is passed from your home network via international data transit to your mobile phone.

What happens when you use the mobileinternet abroad? When abroad and accessing the mobile internet, including

push e-mail, handset internet and mobile broadbandservices, also called Packet Switched Data (PSD), yourconnection is established by the visited operators network back to your home operators network.

The visited operators network passes your internet traf cvia international data transit to and from your home network.

Your home network connects you to the internet, youre-mail account(s) and other data services.

How do network operators exchange billingin ormation or roaming customers?For all data services (and voice calls), the visited networkcaptures the details of every session in a Call Detail Record(CDR). These record information on the location, sendingparty, receiving party, time o connection, session durationand size (measured in KB or MB).

The visited network operator then uses these details tocalculate the wholesale roaming charge payable by yourhome network. The data records, including the applicablewholesale charges, will be saved in a Trans erred AccountProcedure (TAP) file.

TAP files are sent from the visited network to your homenetwork, typically by using the services o a data clearinghouse. A data clearing house acts as a hub or thedistribution of TAP files and provides the home network witservices such as reporting to assist the home network inrunning its roaming business. Your home network then paysthe visited network the appropriate wholesale charges.

What is the difference between pre-paid andpost-paid roaming?Roaming for pre-paid customers is a more recentdevelopment and involves additional investment byoperators. This is because roaming signalling and billingsystems are more complex for pre-paid services than theyare for post-paid services.

For post-paid roaming, when the user first switches theirphone on, the visited network checks in real time whether thehome network authenticates the customer and authorises itsuse abroad. But the data records (CDRs) with the details oneach SMS and data session are sent to the home operatorwith some delay (up to several days).

For pre-paid roaming, in addition to the initial authenticationstep, the call-related data must be exchanged in real timebetween the visited network and the home network by usinga special platform (called CAMEL Customized Applicationsfor Mobile networks Enhanced Logic), to prevent thebalance o the roaming customers account rom becomingoverdrawn.

What are wholesale charges and how dooperators set them?Wholesale charges represent the ees the visited networkcharges the home network or letting the home networkscustomers roam on its network.

These inter-operator tariffs (IOTs) are agreed bilaterallybetween the home and visited network operators. Operatorso ten negotiate competitive incentives, or instance, discountsrelating to the volume of traf c passed between operators orlower costs or longer sessions.

Wholesale charges are paid to the visited network by thehome network, irrespective o whether the home networkrecovers any ees rom its roaming customers.

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Who pays for what?

Sending and receiving SMSWhen a customer sends an SMS while roaming, the retailprice he pays refects several cost elements: the wholesalecharge or using the visited network, costs o handling androuting the roaming SMS back to the home network, costs

or sending the SMS to the receivers network, data clearinghouse ees, signalling ees between the networks and othercosts (e.g. commercial costs, IT costs, prepay checks), thehome operators retail costs and taxes, such as VAT.

Most operators do not charge or receiving an SMS whileroaming. The sender o the SMS also only pays the usual

price as i the receiving customer were on their homenetwork. Hence mobile operators bear the additional costso handling the received roaming SMS without chargingcustomers or it.

Sending and receiving MMSWhen a customer sends a MMS while roaming, the retailprice he pays refects several elements: the wholesale charge

or using the visited network, costs or international transito the roaming MMS back to the home network, costs orsending the MMS to the receivers network, data clearinghouse ees, signalling ees between the networks and othercosts (e.g. commercial costs, IT costs, prepay checks), thehome operators retail costs and taxes, such as VAT.

When the roaming customer receives an MMS, the retailprice includes the MMS cost plus the cost o an SMS sentto noti y the receiving handset that an MMS is ready to bedownloaded. Some operators do not charge or receivingan MMS while roaming and there ore bear the costs o delivering the MMS without passing these on to customers.

Using internet data servicesWhen a customer connects to the internet while roaming, orexample to receive push e-mail or read the news, the retailprice he pays has to cover the ollowing elements: signallingnetwork ees, the wholesale charge or using the dataconnection on the visited network, costs or the internationaltransit o the data, costs or connecting to the internet romthe home network, data clearing house ees, other costs(e.g. commercial costs, IT costs, prepay checks), the homeoperators retail costs and taxes, such as VAT.

The usage o internet data services is generally measured by

data volume usage, which is highly dependent on the typeof device and services used. Checking e-mails, for example,typically uses less data than downloading an MP3 song.The visited network operator, however, has no visibility o what type o data services visiting customers are using andthere ore the wholesale price charged to the home operatorscan only be based on the data volume used per customer.

Selected key elementsenabling SMS and dataroaming Signalling network: Services

which enable the exchange of roaming related signalling traf cbetween the home network and the visited networks.

Home Location Registers (HLRs):These are databases used to store customers profiles.Communication between thesedatabases and Visitor LocationRegisters of the visited network allows roaming to take place.

Visitor Location Registers (VLRs):These are databases used to store information about customers, including those who roam. Communication betweenthese databases and HLRs of thehome network allows roaming to take place.

SMS welcome servers: Operatorsuse these computer servers to identify and send SMS messages to roaming customers upon arrival in the visited country.

Traf c management platforms:These services allow operators to determine preferred networks for roaming and manage roaming traf c distribution.

International transit: Every timedata is transferred between the visited country and the home

country, an international data transit/backbone network is used. Data clearing house: A third party

that acts as a hub for reporting,the exchange of data records (CDRs) and settlement betweenoperators.

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Common acronyms 3G: Third Generation mobile network standards. Besides

better voice quality, 3G networks allow for faster data transfer than GPRS. 3G is often also called mobilebroadband.

CAMEL: Customized Applications for Mobile networksEnhanced Logic. It is an Intelligent Network designed towork on either GSM or 3G core networks. CAMEL helpsmake pre-paid roaming user friendly, with features suchas no-prefix dialling, real-time billing and being able tomake and receive voice calls, SMS, MMS and use data services while abroad.

CDR: Call Detail Record. This is the record of a voice call oran SMS, with details such as origin, destination, duration,time of day, amount charged for each call or SMS.Roaming partners must share CDRs for accurate inter- operator settlement.

GPRS: General Packet Radio Service. A packet-basedmobile data service, mostly used to access e-mail andthe internet from mobile phones. 3G standards are faster alternatives to GPRS.

HLR: Home Location Registers. These are databases used

to store customers profiles. Communications betweenthese databases and VLRs of the visited network allowsroaming to take place.

IOT: Inter Operator Tariff. This is the wholesale fee thatthe visited network operator charges the home network operators for allowing the roaming customer to make calls or use data services.

IP: Internet Protocol. This is the main protocol to enableaccess to the internet and the Web. It is used in combination with GPRS/3G data transfers.

KB: Kilobyte. Measure for the size of data uploads and

downloads. One KB equals 1,000 bytes with each byte carrying the equivalent of one single character such as the letter A.

MB: Megabyte. Measure for the size of data uploads anddownloads. One MB equals 1,000 KB.

MMS: Multimedia Messaging Service. This is an extensioof SMS, which uses an SMS to notify the mobile device of a new MMS and GPRS or 3G to download the actuamessage and the included multimedia content.

MO: Mobile Originated. Refers to any communication

whether voice, messaging or data, that is initiated by a mobile phone.

MT: Mobile Terminated. Refers to any communicationwhether voice, messaging or data, that is terminated on a mobile phone.

MTR: Mobile Termination Rate. This is the fee chargedmobile operators to terminate a call on their network.

PSD: Packet Switched Data. Describes data services thatuse a combination of GPRS/3G and IP, such as pushe-mail or mobile web browsing.

SMS: Short Message Service. Popular service to send shomessages (each 160 characters) directly from one mobile phone to another.

TAP: Transferred Account Procedure. The TAP is themechanism by which operators exchange roaming billing information (CDRs). This is how roaming partners are ablto bill each other for the use of networks and services through a standard process.

VLR: Visiting Location Registers. These are local databasused to temporarily store information about customers,including roaming customers. Communication between

these databases and HLRs of the home network allowsroaming to take place.

More information

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GSM Facts About 70,000 new GSM connectionsare made globally every hour(Source: Wireless Intelligence 2008) There are over 3 billion GSM and 3Gconnections globally(Source: Wireless Intelligence 2008)

European mobile subscribers

Population of Europe: 500 million(EU27 + Iceland, Liechtenstein,Norway, Source: Eurostat 2007) Number of SIMs in Europe:594 million (EU27 + Iceland,Liechtenstein, Norway, Source: Wireless Intelligence 2007)

Where to go or morein ormation To help mobile phone customersidenti y and compare data roamingtari s between operators, theGSMA has set up an independentwebsite with regularly updated tari in ormation:www.roaming.gsmeurope.org

For urther questions onroaming please contact: [email protected] Produced by the GSMA in co-operation with A.T. Kearney

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Sms Data Roaming Explained