IV. CONCLUSIONS
In this paper, an approximation method is used for evaluating
the GPRS performance of single-slot service in the variable
radio resource. By the comparison of numerical results and
simulated results, it shows that the method could be used for
evaluating GPRS performance when the average service time
of circuit switched services is much longer than that of GPRS,
e.g., p&&,>lOO. The simulations show that the interruption
probability of GPRS calls due to releasing its channel to the
demand of circuit switched services depends on the average
message size more strongly than on the traffic load. The
multi-slot services cause higher blocking probability and
longer delay to the network than the single-slot service.
However, according to the simulation those effects can be
reduced by implementing a GPRS resource allocation scheme
with flexible multi-slot services. In this scheme, when the
available network resource cannot provide a call with its
required transmission rate, the network negotiates with the
user and agrees on a transmission rate which the network can
provide.