 the licensed band, used as the primary channel, supports control plane (signaling) and traffic plane (IP packets). The radio channel operating in the U-NII band, used as a secondary channel, supports only the data of the traffic plane. 11.3. Procedures 11.3.1. LWA 11.3.1.1. WT Addition procedure The WT Addition procedure is initialized by the eNB entity and is used to establish the mobile context at the AP to provide mobile resources over the Wi-Fi interface (Figure 11.5). 1) The eNB entity transmits to the access point (AP) the message Xw-AP WT Addition Request in order to allocate resources to the mobile, indicating the characteristics of the LWA bearer. 2) If the access point can accept the resource request, it responds with the message Xw-AP WT Addition Request Acknowledge. 3) The eNB entity sends the message RRC ConnectionReconfiguration to the mobile, indicating the configuration of the radio resource. 4) The mobile applies the new configuration and responds to the eNB entity with the message RRC ConnectionReconfigurationComplete 5) The mobile associates with the access point, which then transmits the message Xw-AP WT Association Confirmation to the eNB entity. 208 Wi-Fi Integration to the 4G Mobile Network Xw-AP WT Addition Request Xw-AP WT Addition Request Acknowledge RRC ConnectionReconfiguration RRC ConnectionReconfigurationComplete Xw-AP Mobile association WT Association Confirmation Figure 11.5. WT Addition procedure 11.3.1.2. WT Modification procedure The WT Modification procedure can be initialized either by the eNB entity or by the access point and can be used to modify, set or release bearer contexts or to modify other properties of the mobile context. Xw-AP WT Modification Request Xw-AP WT Modification Request Acknowledge RRC ConnectionReconfiguration RRC ConnectionReconfigurationComplete Figure 11.6. WT Modification procedure initiated by the eNB entity The WT Modification procedure initiated by the eNB entity is described in Figure 11.6. 1) The eNB entity sends the message Xw-AP WT Modificatio