BN: 0-470-86267-X GPRS: Network Planning and Optimisation 5.1 INTRODUCTION GSM was capable of providing a data rate of 9.6 kbps on a single time slot. With the advent of high-speed circuit-switched data (HSCSD), the capability of the network was increased multi-fold, to 115.2kbps. In practice, however, it was only 64 kbps owing to the limitation of the A-interface and the core network. The main benefit of the implementation of HSCSD was that, with limited upgrading (i.e. minimum investment), the capacity for data transfer was increased to up to four TS on the receiving side and two TS on the transmitting side. But the traffic was still circuit-switched, which meant a long access time to the network. As charging is proportional to the logging time, the subscriber ends up paying more. This led to the evolution to the packet-switched network. In this technology, the access time to the network is reduced and charging is done solely on the usage of the network; i.e. even when a connection is there but not being used, the subscriber is not charged. Usage of the network resources becomes more dynamic and efficient. They are no longer reserved for a user logged to the network, even when he is not using the resources. This system was known as a general radio packet system (GPRS). GPRS is an addition to the existing GSM system, enabling packet-switched transmission in the network whilst keeping the existing value-added services like SMS, etc. Because of this, data rates increase substantially: the user now can log into the GPRS network, and can make use of all eight TS dynamically and be charged only when using the resources. The packet data can be sent during idle times also, between speech calls, thus making effective use of the network resources and saving money for the subscriber. Fundamentals of Cellular Network Planning & Optimisation A.R. Mishra. © 2004 John Wiley & Sons, Ltd. ISBN: 0-470-86267-X GPRS: NETWORK PLANNING AND OPTIMISATION 5.2 THE GPRS SYSTEM GPRS technology is an addition to the existing GSM technology