GPRS

GPRS (General Packet Radio) Service and is a second generation (2G) and third generation (3G)--or sometimes referred to as in-between both generations, 2.5G--wireless data service that extends GSM data capabilities for Internet access, multimedia messaging services, and early mobile Internet applications via the wireless application protocol (WAP), as well as other wireless data services.

GPRS usage is typically charged based on volume of data. This contrasts with circuit switching data, which is typically billed per minute of connection time, regardless of whether or not the user transfers data during that period.

GPRS is a best-effort service, implying variable throughput and latency that depend on the number of other users sharing the service concurrently, as opposed to circuit switching, where a certain quality of service is guaranteed during the connection. In 2G systems, GPRS provides data rates of 56–114 kbit/second. 2G cellular technology combined with GPRS is sometimes described as 2.5G, that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate-speed data transfer, by using unused time division multiple access channels in, for example, the GSM system. GPRS is integrated into GSM Release 97 and newer releases.

GPRS is a method of enhancing 2G phones to enable them to send and receive data more rapidly. With a GPRS connection, the phone is "always on" and can transfer data immediately, and at higher speeds: typically 32 - 48 kbps. An additional benefit is that data can be transferred at the same time as making a voice call. GPRS is now available on most new phones.

GPRS Class Types

The class of a GPRS phone determines the speed at which data can be transferred. Technically the class refers to the number of timeslots available for upload (sending data from the phone) or download (receiving data from the network). The timeslots used for data are in addition to the slot that is reserved for voice calls. These timeslots are available simultaneously, so the greater the number of slots, the faster the data transfer speed. Because GPRS transmits data in packets, the timeslots are not in use all the time, but are shared amongst all users of the network. That increases the overall data capacity of the network, and it also means that you are billed for the quantity of data transmitted, not the time that you are online. It may mean that during busy times, data transfer rates slow down, because the network will give priority to voice calls. Generally speaking, the higher the GPRS class, the faster the data transfer rates.

The most common GPRS classes in use are as follows:

Services offered

GPRS extends the GSM Packet circuit switched data capabilities and makes the following services possible:

• ·         SMS messaging and broadcasting
• ·         "Always on" internet access
• ·         Multimedia messaging service (MMS)
• ·         Push to talk over cellular (PoC)
• ·         Instant messaging and presence—wireless village
• ·         Internet applications for smart devices through wireless application protocol (WAP)
• ·         Point-to-point (P2P) service: inter-networking with the Internet (IP)
• ·        Point-to-Multipoint (P2M) service: point-to-multipoint multicast and point-to-multipoint group calls

If SMS over GPRS is used, an SMS transmission speed of about 30 SMS messages per minute may be achieved. This is much faster than using the ordinary SMS over GSM, whose SMS transmission speed is about 6 to 10 SMS messages per minute.

http://en.wikipedia.org/wiki/General_Packet_Radio_Service

http://mobileoffice.about.com/od/glossary/g/gprs.htm

http://www.mobile-phones-uk.org.uk/gprs.htm