ious example. It is possible to use all of these and to load each with a number of users ( a maximum of 9 in the downlink direction and 7 in the uplink). However, under such circumstances the data rate offered to each user will be low in comparison with that theoretically offered by the coding scheme, and the overall end-to-end message delay will tend to be high where user message sizes are large. Since the distribution of required data transmissions is not expected to be steady (it may be likely to be Poisson distributed, for example) some overhead should be allowed in system resources to accommodate peaks in the load, in order to preserve a satisfactory user data rate. Increasing the GPRS Capacity As shown, a typical network will, at most times, have some limited available capacity for GPRS traffic. To increase the available capacity, further resources will be required in the form of traffic channels (and, hence, carriers). Adding an extra carrier to a cell will create a further seven or eight channels, depending on whether the first timeslot is defined as a control channel or a traffic channel. In all of the cases shown in Table 2.15, the addition of seven or eight TCHs adds significant capacity to the GPRS; in the case of three carriers and 2 % circuit switched blocking, the typical resource available for the GPRS is effectively more than doubled by the addition of a single carrier (for the same circuit switched traffic level). Circuit Switched and GPRS Load Division - The Territory Method * The primary technique for dividing resources between circuit and packet traffic is known as the Territory Method. Here, the timeslots within a cell are dynamically divided into GSM and GPRS territories. This means that a certain number of consecutive traffic timeslots are reserved for circuit switched GSM calls, with the remainder being available for GPRS traffic. A dynamic variation of the territory boundary (and * Note that this type of method may be vendor dependent. Radio Network Planning and Optimisation Traffic Tota