General Packet Radio Service

GPRS packet-based services cost users less than circuit-switched services since communication channels are being used on a shared-use, as-packets-are-needed basis rather than dedicated to only one user at a time. It is also easier to make applications available to mobile users because the faster data rate means that middleware currently needed to adapt applications to the slower speed of wireless systems are no longer be needed. As GPRS has become more widely available, along with other 2.5G and 3G services, mobile users of virtual private networks (VPNs) have been able to access the private network continuously over wireless rather than through a rooted dial-up connection.

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.

GPRS is a key milestone for GSM data. It offers end users new data services and enables

operators to offer radically new pricing options. Using the existing GSM radio infrastructure, up−front

investments for operators are relatively low. GPRS solutions began appearing initially in 1999

through 2000 using the infrastructures that are already in place. Pricing for use of the voice side of

the network has become commoditized, whereas pricing models for the new data access will cause

a revolution. One such threshold looks at an all−you−can−eat model whereby users of wireless

phones add a data subscription at $29.95 per month for unlimited use. Another such model is the

one used in Japan by DoCoMo, charging a rate of the U.S. equivalent to $.0025 per packet. Others

will emerge that will shake the industry mode and create new dynamics in the use of data

anywhere.

GPRS services were targeted at the business user. However, the services will soon be available

networkwide, targeting both the business and the residential consumer. The widespread adoption

and acceptance of GPRS will create a critical mass of users, driving down costs while offering better

services. These components will form the basis of a healthy mobile data market with growth figures

comparable to GSM voice−only services today. Research by Infonetics indicates that the movement

of the user community will also be to a more mobile community. In fact, the study indicates that by

2005, more wireless devices will be used for the Internet than PCs on the Net, as shown in Figure

24−3. This form of growth is again a driver that will force the rapid deployment by carriers and

manufacturers alike.