GSM was the most successful second generation cellular technology, but the need for higher data rates spawned new developments to enable data to be transferred at much higher rates. The General Packet Radio Service (GPRS) is an enhancement to the existing GSM network infrastructure and provides a connectionless packet data service. The same cellular base-stations that support voice calls are used to support GPRS and as a consequence GPRS can be used wherever it is possible to make a voice call. GPRS roaming agreements exist with a large number of countries and this means users can use GPRS devices whilst abroad. GPRS is based on internet Protocols (IP) and enables users to utilize a wide range of applications – email and internet and/or intranet resources for instance. With throughput rates of up to 40 Kbit/s, users have a similar access speed to a dial-up modem, but with the convenience of being able to connect from anywhere.
Basic Overview of GPRS
GPRS (General Packet Radio Service) is a service within the GSM network, just like the two most popular services SMS and voice connections. GPRS is used for transmitting data in the GSM network in from of packets. The connection to the remote station is not reserved and left open during the entire connect time, but is occupied only at the time of actual data transmission.
GPRS is based on internet Protocols (IP) and enables users to utilize a wide range of applications – email and internet and/or intranet resources for instance. With throughput rates of up to 40 Kbit/s, users have a similar access speed to a dial-up modem, but with the convenience of being able to connect from anywhere.
GPRS devices are extremely versatile. The devices allow the owner to use it for many different things. Any device that has GPRS capability will allow the user to have not only mobile communication but also access to the internet for things such as e-mail, and internet browsing. Some devices even have the ability to act as a means of communication between two individuals (such as a parent and a child or a family member and an elderly person). This is done by keeping on part of the device with each party. You can even adjust various settings on the device in order to keep track of thinks like changes in temperature, sound and motion. GPRS devices also have the ability to further its functionality by allowing the user to add on things like cameras and GPS receivers.
GPRS is a packet-based data bearer service that is delivered as a network overlay to existing GSM networks. GPRS is often described as 2.5G cellular technology that lies between second (2G) and third (3G) generation and has evolved because of increased demand of data services over GSM network which otherwise was primarily for voice communication.
Table: GPRS Network Elements
|BTS||Base transceiver station|
|BSC||Base station controller|
|MSC||Mobile switching center|
|SGSN||Serving GPRS support node|
|GGSN||Gateway GPRS support node|
|OMC||Operation and Maintenance Center|
|HLR||Home location register|
|EIR||Equipment identity register|
|SMSC||Short message service center|
Architecture of a GPRS network as an overlay system to basic GSM network is shown in Figure. Various network elements are defined in Table
Figure: GPRS Network Architecture
To have packet-based data communication over existing circuit switched infrastructure of GSM some additional network elements, interfaces and protocols are required to be introduced. Each BSC requires installation of one or more packet control units (PCUs) and a software up-gradation. PCU provides a physical and logical data interface to the base station subsystem for packet data traffic. When a voice or data communication request is originated from ME, it is transported over the air interface to BTS, and from BTS to BSC in the same way as a standard GSM call. At BSC both are separated; voice is sent to MSC and data is sent via PCU to a network path dedicated to GPRS. This network path includes two elements viz. SGSN and GGSN. These elements are primarily mobile aware routers and are interconnected via an IP backbone network. Role of SGSN is analogous to that of MSC in circuit-switched communication. It is responsible for data packet exchange with base station subsystem and for other functions like authentication of GPRS mobiles, registration of mobiles in network, mobility management, recording billing information, etc. GGSN acts as an interface and a router to external PDN. GGSN contains routing information for GPRS users that helps to pass packets through IP based internal backbone to correct SGSN. GGSN also records billing information for use of external data networks and also acts as a packet filter for incoming data. GR as a part of operation subsystem is used to manage information related to each GPRS subscriber as well as routing information.
 “GPRS General Packet Radio Service Tutorial”, available online at: https://www.radio-electronics.com/info/cellulartelecomms/gprs/gprs_tutorial.php
 “What is GPRS and how is it used with GPS Tracking Devices”, available online at: https://www.liveviewgps.com/blog/what-is-gprs-and-how-is-it-used-with-gps-tracking-devices/
 “Basics: How does GPRS work?” available online at: https://www.insys-icom.com/gprs-basics
 “Chapter 4: GPRS Technology”, available online at: http://shodhganga.inflibnet.ac.in/bitstream/10603/46043/11/11_chapter%204.pdf
 “GPRS: How it works”, An O2 White Paper, available online at: http://www.o2.co.uk/assets2/PRODImages/PDF/GPRS-howitworksMar07.pdf