Tuesday, July 8, 2008

GSM World

Today's GSM Platform

Today's GSM
GSM (Global System for Mobile communications) is the technology that underpins most of the world's mobile phone networks. The GSM platform is a hugely successful wireless technology and an unprecedented story of global achievement and cooperation. GSM has become the world's fastest growing communications technology of all time and the leading global mobile standard, spanning 218 countries. Today, GSM technology is in use by more than one in three of the world's population - by June 2008 there were over 2 billion GSM subscribers, representing approximately 86% of the world's cellular market. The growth of GSM continues unabated with almost 400 million new customers in the last 12 months (source: www.wirelessintelligence.com) The progress hasn't stopped there. Today's GSM platform is living, growing and evolving and already offers an expanded and feature-rich 'family' of voice and multimedia services.

What is GSM?

GSM (Global System for Mobile communications) is an open, digital cellular technology used for transmitting mobile voice and data services. GSM differs from first generation wireless systems in that it uses digital technology and time division multiple access transmission methods. GSM is a circuit-switched system that divides each 200kHz channel into eight 25kHz time-slots. GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz and 850MHz bands in the US. The 850MHz band is also used for GSM and 3GSM in Australia, Canada and many South American countries. GSM supports data transfer speeds of up to 9.6 kbit/s, allowing the transmission of basic data services such as SMS (Short Message Service). Another major benefit is its international roaming capability, allowing users to access the same services when travelling abroad as at home. This gives consumers seamless and same number connectivity in more than 210 countries. GSM satellite roaming has also extended service access to areas where terrestrial coverage is not available.

Traveling with your GSM

Did you know that you can be instantly contactable on your usual number in over 100 countries world wide, when you travel with your GSM phone using your own number? The major advantage of GSM technology is that it allows you to use your GSM phone when you travel outside your own country or region. This is known as roaming. Roaming is the ability to use your own GSM phone number in another GSM network. You can roam to another region or country and use the services of any network operator in that region that has a roaming agreement with your GSM network operator in your home region/country. A roaming agreement is a business agreement between two network operators to transfer items such as call charges and subscription information back and forth, as their subscribers roam into each other's areas.


GSM Roaming

Roaming is defined as the ability for a cellular customer to automatically make & receive voice calls, send & receive data, or access other services when travelling outside the geographical coverage area of the home network, by means of using a visited network. Roaming is technically supported by mobility management, authentication and billing procedures. Establishing roaming between network operators is based on - and the commercial terms are contained in - Roaming Agreements. If the visited network is in the same country as the home network, this is known as National Roaming. If the visited network is outside the home country, this is known as International Roaming (the term Global Roaming has also been used). If the visited network operates on a different technical standard than the home network, this is known as Inter-standard 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 210 countries*. The convenience of GSM Roaming has been a key driver behind the global success of the GSM Platform.

How Does Roaming Work?

1. What do I need to do before I leave?

You need to check with your operator that your mobile subscription allows you to use your phone abroad and which services are available in your destination country. A simple phone call is all that is normally required.

You should also check that your operator has a 'roaming agreement' with an operator in the country that you are visiting. Your operator will be able to provide a list of all of the countries you can roam to.

Finally, you should check that your mobile phone supports the radio frequency employed in that region of the world. GSM services are provided in a number of bands (e.g. 850, 900, 1800 and 1900 MHz). Most modern phones are multi-band, but travellers from Europe to North America, for example, should check that their phones will operate in the 850 and/or 1900 MHz bands.

2. How does my mobile work in foreign countries?

When you travel to a different country with your mobile phone, your home operator may not have coverage in the place you have travelled to. However, you are still able to make and receive calls because your mobile phone can 'roam' onto another operator's network, in the visited country.

This is possible because your home operator has a 'roaming agreement' with an operator in the visited country that enables you to use its network.

When you switch on your phone in the foreign country, your mobile phone picks up the radio signals of one of the operators in that country. This local operator will then 'authenticate' your mobile phone with your home operator (e.g. check if you are a valid customer, whether you are allowed to roam, etc.). If your home operator responds with a positive authentication, your mobile phone is ready for use.

All you have to do is to switch your phone on. Operators have done a lot of work behind the scenes to make this process completely automatic and it typically takes only a few minutes to log on to the local network.

3. When I want to make a call when roaming, what actually happens?

When you are roaming and you make a call, the operator in the visited country analyses the dialled number, and decides how best to route the call.

If you are calling back home, then the visited operator will connect the call back to your home country.

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 UK mobile number 07903 XXX XXX from another country, you dial +44 7903 XXX XXX. If you are calling a landline, you may need to include an area code.

If you are calling a local number in the visited country, the visited operator will usually connect the call directly to the party within the country you are in.

4. Is this different if I receive a call?

When someone calls you on your mobile, the call will usually be routed to your home country and your home operator. Your home operator knows where you are roaming, and will then forward the call to the operator whose network you are using in the visited country. The visited network will then connect the call to you.

This initial routing back to your home operator happens regardless of where the call originates, as only your home operator has the information about your location.

Note that when roaming you have to pay both for calls that you make and receive.

5. How do I get billed for making and receiving calls?

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.



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