GSM GPRS EDGE?

GSM is an acronym for global system for mobile communication. It works at 900 MHz band and uses 124 full duplex channels. GSM offers full international roaming, automatic location services, authentication, and encryption on the wireless link, efficient interoperation with ISDN systems, and a relatively high audio quality. Further more, a short message service with upto 160 alphanumeric characters, fax group 3, and data services at 9.6 Kbit/s have been integrated. Depending on national regulations, one or several providers can use the channels, different accounting and charging schemes can be applied etc. however all GSM systems remain compatible. Providers in more than 130 countries have adopted the GSM standard at 900 MHz worldwide. The digital GSM at 900 MHz in some countries was not sufficient for the high user densities in cities. Therefore a new frequency band at 1800 MHz was chosen. These GSM-1800 networks (also known as DCS 1800, digital cellular system) operate with a better voice quality and smaller cells, and thus are better adapted to business use in big cities. In India service providers fastly adopting the 1800 MHz networks. Nowadays GSM is also available in the USA as GSM-1900 (also called PCS-1900) using spectrum at 1900 MHz like the newer versions of the TDMA and CDMA system. If you are traveling to USA and have a international roaming sim card than you must use Triband handset for roaming. 

GPRS 
1. GSM: the GPRS base
Before beginning to speak of GPRS (Global Packet Radio Service), we at any time see the characteristics of present technology GSM for the shipment of wireless data from any place and: Speed of transference of 9.6 Kbps. 
Time of establishment of connection, 15 to 30 seconds.
Payment per connect time. 
The low speed of transference limits the amount of services that Internet offers to us. For example, to 9.6 Kbps cannot be sailed by Internet of a satisfactory way. If, in addition, we consider that we are paying per connect time, the costs go off. The combination of these three negative factors causes that GSM is a technology mainly used for the voice and does not stop the data. 


2. GPRS: the immediate reality
GPRS is a nontraumatic evolution of present network GSM: it does not entail great investments and it reuses part of present infrastructures of GSM. For this reason, GPRS will have, from their beginnings, the same cover that present network GSM. GPRS (Global Packet Radio Service) is a technology that corrects the GSM deficiencies: 
Speed of transference of up to 115 Kbps. 
Permanent connection. Time of establishment of inferior connection to the second.
Payment by amount of transmitted information, not per connect time.

GPRS can combine up to 8 channels to transfer data, and each channel can transfer at a 10 speed of Kbps, approximately. It is evident that, to be able to serve to us as this new technology, we needed a new terminal. Our movable telephone GSM does not serve. New terminals GPRS will count on diverse benefits based on I number of channels that use. Due to this, we will count on terminals 2 + 1 (that mean two channels to receive information and a channel for the shipment), 3 + 1, 4 + 1, etc. Also there will be terminals that will allow to transfer data and to maintain, at the same time, a voice call. The GPRS use is not limited only the movable telephones; they will appear cards PCMCIA GPRS to connect portable to Internet, cards to connect the desktop computer, etc.

The use of new terminals GPRS as wireless modem has an immediate and evident application. We will be able to connect to laptops or of tablecloth like any modem, but, evidently, with the advantages of being wireless.

Also, terminals GPRS will allow us to visualize contents and to directly use services of Internet in their reduced screen, a continuous evolution of convergence between the movable telephone and PDA (Asistentes Digitales Personales). This new terminal, of reduced screen and keyboard with limited functions, counts on permanent connection to Internet (GPRS) and a payment by use on watch, not per time, which will give rise to new movable services.

When we accede directly to services from our terminal, the speed of transference, unlike which it can seem, is not the determining factor. To have a permanent connection to Internet (what it is translated in acceding to services of almost instantaneous way) or the fact of not being paying per connect time they are factors more excellent than the speed of transmission. But, over the everything, most important it is, without a doubt, to be able to have all those services.

The natural evolution of GPRS is UMTS (Universal Mobile Telephony System). UMTS requires a new technology of radio (great infrastructure investments), a network of greater capacity (because the speeds of transference vary of 384 Kbps to 2 Mbps) and new terminals. These factors to make anticipate that UMTS will take a certain time in settling down and that GPRS, given their greater cover, will maintain a use high. It is necessary to emphasize that no technology is excluding to each other. The GPRS appearance does not exclude GSM; also, UMTS does not imply the GPRS cancellation.


What is EDGE?
Further enhancements in data capability over the core GSM network will be provided with the introduction of Enhanced Data rates for GSM Evolution - known as EDGE*. This will achieve the delivery of advanced mobile services such as the downloading of video and music clips, full multimedia messaging, high-speed colour Internet access and e-mail on the move.

EDGE (or Enhanced Data Rates for Global Evolution) is a 3G technology that delivers broadband-like data speeds to mobile devices. It allows consumers to connect to the Internet and send and receive data, including digital images, web pages and photographs, three times faster than possible with an ordinary GSM/GPRS network. EDGE enables GSM operators to offer higher-speed mobile-data access, serve more mobile-data customers, and free up GSM network capacity to accommodate additional voice traffic.