Intensive research efforts to integrate 3G cellular networks (such as UMTS) and IEEE 802.11 WLAN networks have been stimulated due to the complementary characteristics of UMTS and WLAN. In such integrated system, access control problems like channel partitioning, channel allocation to mobile nodes of both networks and switching of mobile nodes in the networks. In this paper, we propose a modified channel partition scheme which implements a utility based load balancing algorithm to solve these access control problems of the internetworking systems. The proposed model improves QoS parameters such as dropping probability, call handling efficiency of the system when compared to existing model C-WLAN. © 2013 IEEE.