The Network Management Center needs to be highly intelligent to control the network devices for Quality of Service (QoS) assurance. To make sure the traffic of the call and the data as well as the satisfaction from the customers, we develop a decision support (DS) mechanism for the 4G mobile networking with QoS awareness. In this study, real experimental results are explored from the WiMAX equipment. The MRTR parameter is automatically adjusted by the K-Means clustering algorithm. We show that automated DS mechanism can be achieved with QoS guarantee for 4G mobile network.