This paper presents a technique to control based on interval type-2 fuzzy logic system (IT2FLS) of Mamdani fuzzy inference, employed to model connection admission control in Fourth Generation (4G) Networks in order to improve quality of service (QoS). The appropriate parameter selection to achieve connection admission control is also considered based on major system parameters like latency, packet loss, load, signal strength and user mobility. We explore the use of Karnik-Mendel (KM) and Wu-Mendel (WM) approaches in our proposed system. We also implement a T1FLS connection admission control for guaranteed QoS in 4G mobile networks for comparison purposes. The empirical comparison is made on the designed system using 4G network admission control synthetic datasets. Analysis of our results reveal that the presence of additional degrees of freedom in IT2FLS-WM controller tend to reduce the root mean square error (RMSE) of the model compared to IT2FLS-KM and fuzzy type-1 approaches