GPRS stands for General Packet Radio Service and is a second generation (2G) and third generation (3G)--or sometimes refered 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 is a cellular networking service that supports WAP, SMS text messaging, and other data communications. GPRS technology is integrated into so-called 2.5G mobile phones designed to provide faster data transfer speeds than older 2G cellular networks.
An always-on packet switching service, mobile Internet providers offered GPRS together with voice subscription packages before 3G and 4G technologies became popular. Customers originally paid for GPRS service according to how much network bandwidth they used in sending and receiving data until providers changed to offer flat-rate unlimited use packages.
Features of GPRS
GPRS was one of the earliest cell phone data access technologies, and more widespread particularly in Europe and Asia, though it was adopted by carriers in North America, such as Rogers in Canada and T-Mobile in the US.
2G (second generation) GPRS service had data rates of 56-114 kbit/second--akin to dial-up modem speeds.
GPRS wireless networks were later enhance faster 3G (third generation) throughput speeds. T-Mobile's EDGE (enhanced Data Rates for Global Evolution), for example, delivers up to 4 times the GPRS rate.
Both GPRS and Edge, however, are quickly being surpassed by even faster 4G (fourth generation) mobile data networks.
How does GPRS work?
GPRS is a network overlay to the existing cellular network. It uses the nature of IP transmissions to its advantage. Because IP traffic is made of "packets", the network does not need to have continuous data transmission. Thus, IP traffic can easily share the channels. A user may be receiving or transmitting data while another one is reading information. The second user does not need to use the channel during this time, and it makes packet networks more efficient than circuit-switched networks (2G), where the channel would be in use, regardless of the user transmitting or not.
Each channel is divided into eight time slots, with a maximum data transmission of 13.4Kbps. One of these time slots is used for control, and normal allocation would reserve two slots for voice traffic as well. Asymmetric traffic (more download than uploads) dictates the distribution of the remaining time slots:
Type
Meaning
2+1
two slots for download + 1 for upload
3+1
three slots for download + 1 for upload
4+1
four slots for download + 1 for upload
Also, the GPRS devices have a classification related to their ability to handle GSM voice calls and GPRS connections:
Class
Meaning
A
devices are capable of simultaneous voice and data transmission
B
devices support one type at a time, and switch automatically between data and voice
C
devices support one type at a time, and require user intervention to switch between data and voice
The connection to the GPRS network is always on, but the device needs to connect to the data terminal (Pocket PC, notebook, cellular phone). The connection times are of course much lower than dial up. My personal tests show GPRS connection to be ready to use in 7 seconds, while a dial up requires around 35 seconds to be in a ready state.
How to use GPRS
A user can connect to a GPRS enable network in three different ways:
Using a mobile with a microbrowser to access WAP pages
A user can connect to the GPRS and browse WAP pages from a GPRS enabled mobile. Of course the impact of reduced content on WML format and using the little phone keypad to type in URLs is tiresome. Examples are mobile phones such as Ericsson T39m and T68i.
Using a handheld with built in GSM/GPRS capabilities
Using handhelds with GPRS capabilities a user can connect to the GPRS network. All Internet services will be available, providing the needed ports are not blocked. This includes web, e-mail, newsgroups, VPN, ftp, etc. The connection between the terminal and the GPRS modem can be via infrared, serial cable or bluetooth. Examples are Treo, XDA Pocket PC Phone Edition, and Smartphones.
Using a mobile as a GPRS modem.
A user can connect a notebook, desktop or handheld to connect to a GPRS enabled mobile, and then connect to the Internet. All Internet services will be available, providing the needed ports are not blocked. This includes web, e-mail, newsgroups, VPN, ftp, etc. The connection between the terminal and the GPRS modem can be via infrared, serial cable or bluetooth. Examples are using a H3970 to link via Bluetooth to a T39m and from there to the Internet.
Using a PCMCIA card as a GPRS modem
A PCMCIA card can be used as a GPRS enabled modem, and once inserted a dial up connection can be created. From there the user can connect to the Internet. All Internet services will be available, providing the needed ports are not blocked. This includes web, e-mail, newsgroups, VPN, ftp, etc.