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In a mobile cellular system quality of service (QoS) to mobile terminals (MTs) is measured by the probability of forced termination Pft and/or probability of new call blocking (Pb). Since, both cannot be reduced simultaneously, usually keeping the Pft below a designated level DPft is considered as QoS guarantee to the users of the system. However, Pft is related to system parameters namely, maximum capacity of the cell C, the average new call arrival rate λ, the average call holding time 1/μ, and the average cell dwell time 1/η by complex nonlinear equations. Therefore, call admission control (CAC) for maintaining Pft at DPft is a very challenging task. A fuzzy controller is proposed to dynamically maintain Pft at DPft with changes in system parameters. Also, current cellular networks are employing CDMA as the multiple access technique since it provides much more capacity than other techniques. Interference received at the base station (BS) of a cell is considered in the decision making process of whether to admit a call or not. We describe the CAC criteria used in CDMA cellular networks in this paper. Also, through simulation we show that fuzzy controller can be integrated with other CAC schemes to guarantee QoS to the users.