An efficiency limit of cellular mobile systems

We consider cellular mobile systems where in order to limit hando blocking probability, admission control is applied to new call requests and capacity is reserved for future hando attempts. We show that due to this advance reservation the achievable e ciency of the system has an upper bound even if no constraint is speci ed on the blocking probability of new call requests. As a reference case, we rst calculate the e ciency of a system with deterministic advance reservation. Next, we consider systems with statistical reservation and calculate the maximum achievable e ciency, under the set of possible local admission control policies subject to a hard constraint on the probability of call failure due to hando blocking. We relate this maximum to call and mobility characteristics and show that the achievable e ciency decreases with decreasing cell size and with increasing proportion of multimedia calls, both of which are recognized trends today.