  Due to the fact that Quality of Service (QoS) requirements are not as
stringent for non-real-time traffic types, as opposed to real-time traffic,
more calls can be accommodated by releasing some bandwidth from the existing
non-real-time traffic calls. If the released bandwidth to accept a handover
call is larger than to accept a new call, then the probability of dropping a
call is smaller than the probability of blocking a call. In this paper we
propose an efficient Call Admission Control (CAC) that relies on adaptive
multi-level bandwidth-allocation scheme for non-real-time calls. The features
of the scheme allow reduction of the call dropping probability along with the
increase of the bandwidth utilization. The numerical results show that the
proposed scheme is able to attain negligible handover call dropping probability
without sacrificing bandwidth utilization.
