h the LWIP tunnel. 212 Wi-Fi Integration to the 4G Mobile Network 7) The mobile applies the new configuration and responds with the message RRC ConnectionReconfigurationComplete. 8) The mobile sends the confirmation of the association with the Wi-Fi access point to the eNB entity in the message RRC WLANConnectionStatusReport. 9) The eNB entity sends the message RRC ConnectionReconfiguration to the mobile to establish the IPSec tunnel and can configure the bearers that will use the IPSec tunnel. 10) The mobile applies the new configuration and responds with the message RRC ConnectionReconfigurationComplete. RRC ConnectionReconfiguration Measurement RRC ConnectionReconfigurationComplete configuration RRC WLANMeasurements Xw-AP LWIP Addition Request IPSec tunnel Xw-AP LWIP Addition Request Acknowledge configuration RRC ConnectionReconfiguration LWIP tunnel RRC ConnectionReconfigurationComplete configuration RRC WLANConnectionStatusReport Association RRC ConnectionReconfiguration IPSec tunnel RRC ConnectionReconfigurationComplete configuration Figure 11.10. LWIP and IPSec tunnel establishment 11.3.3. LAA aggregation The access mechanism to the radio channel is different for the LTE and Wi-Fi interfaces. Carrier Aggregation For the LTE radio interface, access to the radio channel is controlled by the eNB entity. For the Wi-Fi radio channel, access to the radio channel uses the CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) mechanism. The eNB entity or the mobile applies the LBT (Listen Before Talk) mechanism before transmitting in the U-NII radio channel. The equipment uses energy sensing to determine the presence or absence of other signals on the radio channel during the CCA (Clear Channel Assessment) observation time. The LBT mechanism has two options: frame-based equipment (FBE) and load-based equipment (LBE). For the FBE option, the equipment operates on the basis of a synchronization with a fixed frame period. At the end of the frame period, the equipment performs a CCA check on the radio channel. I