Today there are two major standards for cell phone technology. CDMA and GSM. Almost all phones around the world operate on either of these networks. However, the average person tends to be unfamiliar with these terms. Common cell phone service providers like Verizon and Sprint use CDMA technology, while carriers like T-Mobile,Vodafone,China Mobile and Cingular operate on the GSM network.
GSM stands for Global System for Mobile Communications. It is one of the leading digital cellular systems. GSM uses narrowband TDMA, which allows eight simultaneous calls on the same radio frequency. It was first introduced in 1991. As of the end of 1997, GSM service was available in more than 100 countries and has become the de facto standard in Europe and Asia.
Europeans quickly realized the disadvantages of each European country operating on their mobile network. It prevents cell phone use from country to country within Europe. With the emerging European Union and high travel volume between countries in Europe this was seen as a problem. Rectifying the situation the Conference of European Posts and Telegraphs (CEPT) assembled a research group with intentions of researching the mobile phone system in Europe. This group was called Group Spécial Mobile (GSM).
For the next ten years the GSM group outlined standards, researched technology and designed a way to implement a pan-European mobile phone network. In 1989 work done by the GSM group was transferred to the European Telecommunication Standards Institute (ETSI). The name GSM was transposed to name the type of service invented. The acronym GSM had been changed from Group Spécial Mobile to Global Systems Mobile Telecommunications.By April of 1991 commercial service of the GSM network had begun. Just a year and half later in 1993 there were already 36 GSM networks in over 22 countries. Several other countries were on the rise to adopt this new mobile phone network and participate in what was becoming a worldwide standard. At the same time, GSM also became widely used in the Middle East, South Africa and Australia.
While the European Union had developed a sophisticated digital cell phone system, the United States was still operating primarily on the old, analog AMPS network and TDMA. In the end of October 2001, Cingular was the first to announce their switch to the 3G GSM network. This involved switching more then 22 million customers from TDMA to GSM.In 2005 Cingular stopped new phone activation on the TDMA network and began only selling GSM service.
Today major operators on the GSM network include Cingular/AT&T, and T-Mobile. Other common carriers such as Verizon Wireless and Sprint operate on CDMA networks. Most of the world external to the United States uses GSM technology. However, operate on different frequencies then the United States GSM phones.
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From the beginning, the planners of GSM wanted ISDN compatibility in services offered and control signaling used. The radio link imposed some limitations, however, since the standard ISDN bit rate of 64 Kbps could not be practically achieved.
The digital nature of GSM allows data, both synchronous and asynchronous data, to be transported as a bearer service to or from an ISDN terminal. The data rates supported by GSM are 300 bps, 600 bps, 1200 bps, 2400 bps, and 9600 bps.
The most basic teleservice supported by GSM is telephony. A unique feature of GSM compared to older analog systems is the Short Message Service (SMS). Supplementary services are provided on top of teleservices or bearer services, and include features such as international roaming, caller identification, call forwarding, call waiting, multiparty conversations, and barring of outgoing (international) calls, among others.
There are five major GSM frequencies that have become standard worldwide. They include
- GSM-900 and GSM-1800 are standards used mostly worldwide. It is the frequency European phones operate on as well as most of Asia and Australia.
- GSM-850 and GSM-1900 are primarily United States frequencies. They are also the standard for Canada GSM service and countries in Latin and South America. Most of the Cingular network operates on GSM 850, while much of T-Mobile operates at GSM-1900. T-Mobile however, has roaming agreements with Cingular. Meaning in the case of no service at GSM-1900, the phone will switch to GSM-850 and operate on Cingular’s network.
- GSM-400 is the least popular of the bunch and is rarely used. It is an older frequency that was used in Russia and Europe before GSM-900 and GSM-1800 became available. There is not many networks currently operating at this frequency.
Phones that work on gsm are
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