We validate a call admission control (CAC) method for mobile cellular networks under more restrictive conditions than those assumed in its design. The method uses distribution and the first and second moments of the channel holding time (CHT) parameter to compute the algorithm’s main admission control metric: remaining CHT. Our goal is to generalize the handover method when only the mean and variance of CHT are known, but precise knowledge of the CHT’s complete distribution is not available. The problem is of practical interest because probability distribution fitting can be time- and CPU-intensive. To this end, we use an approximation of the expected remaining holding time instead of its exact value. We show that for a variety of traffic conditions and the general gamma distribution, the approximation yields acceptable results. For a log-normal distribution, our results also suggest that the algorithm can be defined based solely on the mean and variance of CHT.