Fig. 2, 3 and 4 show the mean queueing time and blocking
probability of single-slot service distributed to the traffic load
for the average service time (Up) of 2s, 5s and 10s
respectively. In this paper the average interruption time is
included into the mean queueing time. Comparing the
approximation results with simulation results, we find the
approximation method could be used for evaluating the GPRS
performance when the average service time of circuit switched
services is much longer than that of GPRS, e.g., pJk>lOO.
for the call's requirement, the available channels are
allocated to the call.