A Pragmatic Design for 3GPP/WLAN RAN Level Interworking

As mobile data traffic continues to grow significantly, traffic offloading is an important issue. Since WiFi-capable user equipments (UEs) are very popular nowadays and a Home evolved Node B+ (HeNB+), which is a Home evolved Node B (HeNB)/WiFi access point (WiFi AP) collocated access node, is a common commercial design, this paper proposed a novel and realistic scheme to utilize WiFi capacity for radio access network offloading such that service flows of a 3rd Generation Partnership Project (3GPP) UE could be offloaded to WiFi as needed. To achieve this, three most important issues need to be conquered. First, the 3GPP UE needs to know the correct service set identification of the WiFi AP to offload traffic. Second, the WiFi AP needs to know the WiFi media access control address of the authorized UE to accept the corresponding access request. Third, the uplink offloaded service flow over WiFi needs to be recognized and be transmitted over the corresponding tunnel toward mobile core network. Based on the proposed architecture and solution, even service flows are offloaded to WiFi, UE is still attached to the collocated HeNB and therefore handover procedures will not be affected. In this paper, we also proposed the system design for implementation.