Bandwidth adaptation for joint call admission control to support QoS in heterogeneous networks

Call admission control (CAC) is one of the basic mechanisms for ensuring high quality of service (QoS) offered to the user in Wireless Networks. Based on the available network resources, it estimates the impact of accepting or blocking a new session request. Many CAC algorithms have been proposed in the literature but they were all limited by the available bandwidth. This paper proposes a bandwidth adaptation technique for the Adaptive Joint CAC (AJCAC) algorithm; it is proposed as a solution for congestion; where the AJCAC algorithm degrades the bandwidth of some ongoing users to make room for new incoming ones. A restoration process must take place when the network is underutilized; where the algorithm restores the maximum bandwidth service to the degraded users. In this paper the bandwidth degradation process was investigated and evaluated. The results showed that as the degradation in the bandwidth increases, the adaption required in the network also increases. On the other hand, degradation in the QoS results in decreasing the blocking probability