GPRS General Overview
The General Packet Radio Service (GPRS) allows an end user to send and receive data in packet transfer mode within a public land mobile network (PLMN) without using a permanent connection between the mobile station (MS) and the external network during data transfer. This way, GPRS optimizes the use of network and radio resources (RRs) since, unlike circuitswitched mode, no connection between the MS and the external network is established when there is no data flow in progress. Thus, this RR optimization makes it possible for the operator to offer more attractive fees.

The principles defined for the Global System for Mobile Communications (GSM) radio interface were kept for GPRS, since the notions of time slot, frame, multiframe, and hyperframe have not changed for GPRS as compared with GSM. The GPRS standard proposes multislot allocations for data transmission; the network may allocate up to eight time slots per time division multiple access (TDMA) frame for a given mobile on uplink and downlink. The GPRS standard proposes four channel coding types allowing throughput per slot ranging from 9.05 Kbps to 21.4 Kbps. This allows a theoretical throughput going up to 171.2 Kbps for data transmission when eight time slots are allocated to the MS.