General Packet Radio Services

General Packet Radio Services (GPRS) is a packet-based wireless communication service that promises data rates from 56 up to 114 Kbps and continuous connection to the Internet for mobile phone and computer users. The higher data rates allow users to take part in video conferences and interact with multimedia Web sites and similar applications using mobile handheld devices as well as notebook computers. GPRS is based on Global System for Mobile (GSM) communication and complements existing services such circuit-switched cellular phone connections and the Short Message Service (SMS).

The figure below shows how users can access internet through GPRS. One may use a mobile phone, PDA, or notebook to connect to a GPRS network. A mobile phone can be use as a modem to connect via GPRS.

General Packet Radio Services may also be called 2.5G technology because it is an enchancement of GSM (Global System for Mobile Communication) or TDMA (IS-136) network. It exist in our cellular network infrastructure and enhances the technology by software upgrades at the base station to create a GPRS gateway that connects to the internet.

Because GPRS is a packet switched network, a GPRS user station doesn't occupy a dedicated path during an Internet connection. However, each end user station (e.g. mobile phone) is allocated several time slots out of 8 GSM/TDMA available time-slots for GPRS service. Each time slot has a maximum capacity of 14.4 kbps. Depending on how many time slots are allocated for the downlink (from a base station to a user station) and the uplink (from a user station to a base station), GPRS devices are divided into multi-slot classes. A multi-slot class is often represented by the number of downlink and uplink slots. For example, Class 10 is also known as Class 4+2. While active slots indicate the maximum number of slots that can be allocated for both downlink and uplink in a specific class. The following table lists available multi-slot classes.

With GPRS, it will make mobile data faster, user-friendly and cheaper. It also enables voice and data calls to be handled simultaneously. Instantaneous connection setup is also achievable on mobile internet with high-speed internet access. GPRS was developed to enable GSM operators to meet the growing demands for wireless packet data service that is a result of the explosive growth of the Internet and corporate intranets. Another goal for GPRS is to enable GSM operators to enter the wireless packet data market in a cost−efficient manner. First, they must be able to provide data services without changing their entire infrastructure. The initial GPRS standards make use of standard GSM radio systems. This also includes GSM standard modulation schemes and TDMA framing structures. By doing this, the cost implications are minimized in the cell equipment. Second, GSM operators must have flexibility to deploy GPRS without having to commit their entire network to it. GPRS provides the dynamic allocation and assignment of radio channels to packet services according to the demand.

GPRS Public Land Mobile Networks (PLMN) enables users to roam around within the geographic area and still receive continuous transmission. Either way, the network tracks the location of the MS so that incoming packets can be routed to the MS when they arrive. The GPRS PLMN interfaces with the MSs via the air interface. GPRSs will initially be provided using an enhanced version of the standard GSM interface. The end user is able to access public servers such as web sites and private corporate intranet servers. GPRS can also receive voice services via the GSM PLMN.

Advantages of GPRS

GPRS brought mobile phone users out from the world of WAP, and into a world where Internet was finally available on mobiles. This in itself was a monumental feat, and hence GPRS took off with quite a bang. With GPRS, large amounts of data can be transferred to and from the mobile device over the Internet.

Disadvantages of GPRS

Since GPRS uses the cellular network’s GSM band to transmit data, more often than not, when a connection is active, calls and other network-related functions cannot be used. The data session will go on standby. This is a characteristic typical of the Class B GPRS device. There are Class A devices as well, where there are two radios incorporated into the device, allowing both features to run simultaneously. However, Class A devices tend to be more expensive, and by extension, less popular. Most mobile phones fall in the Class B category.

GPRS is usually billed per megabyte or kilobyte, depending on the individual service provider. However, this has changed in many places, where GPRS downloads are no longer charged as per usage, but are unlimited, and there is merely a flat fee to be paid every month.

http://www.conniq.com/InternetAccess_GPRS.htm

http://searchmobilecomputing.techtarget.com/definition/GPRS