General Packet Radio Service
General Packet Radio Service or GPRS is a digital mobile phone technology. It is considered as 2.5G, between the second and third generation. It provides high-speed data transfer, and is only compatible with GSM networks.
GPRS is basically an addition to enable packet based communications in the TDMA-based GSM system. Timeslots in GSM are normally allocated to create a circuit-switched connection, but for GPRS timeslots are allocated to a packet-connection on an as-needed basis. This means that if no data is sent by a sender, the frequencies involved remain free to be used by others.
GPRS in Practice
Telephone operators have priced GPRS relatively cheaply (compared to older GSM data transfer, HSCSD) in many areas, such as Finland. But the telco operators donīt offer flat rate access to the Internet, instead basing their tariffs on data transfered.
The maximum speed of a GPRS connection (as offered in 2003) is the same as modem connection in an analog wire telephone network, about 5 kB/s (kilobytes per second). Latency is very bad, ping being about 1 second round trip time. GPRS is typically prioritised lower than speech, and thus the quality of connection varies greatly. Most of the limitations are not technical, as GPRS could be made to work a lot faster.
In China (2003), China Mobile provides flat rate GPRS Internet access for 200元 per month, or around USD$25.
