Adaptive call admission control mechanism for DS-CDMA cellular system

In the DS-CDMA (Direct-Sequence Code-Division Multiple-Access) cellular system, a call admission control (CAC) mechanism is needed to determine whether a new arrival user shall be accepted while the transmission quality of existing users can be guaranteed Furthermore, a handoff call shall have a higher priority than a new arriving call. Most of existing CAC mechanisms in the literature reserve a certain number of channels for handoff calls statistically. However, as we will show in this paper, the number of reserved channels; should be adaptive to arrival rates of new calls and handoff calls, moving speed of user, call holding time, as well as the system capacity. Therefore, in this paper, we propose a CAC mechanism with adaptive channel reservation for handoff calls based on the Markov Decision Processes (MDP). Our simulation results show that the proposed scheme can achieve better Grade of Service (GOS) of the system under various configurations.