ll attempt to connect to a Wi-Fi AP whose identifiers match the ones in the configured mobility set. The UE mobility relative to Wi-Fi APs not belonging to the UE mobility set is controlled by the eNB, for example, updating the Wi-Fi mobility set based on measurement reports provided by the UE. A UE is connected to only one mobility set at a time. All Wi-Fi APs belonging to a mobility set share a common WT which terminates Xw-C and Xw-U. The termination points for Xw-C and Xw-U may differ. The Wi-Fi identifiers belonging to a mobility set may be a subset of all Wi-Fi identifiers associated with the WT [5]. The UE supporting LWA may be configured by the LTE RAN to perform Wi-Fi measure- ments. Wi-Fi measurement object can be configured using Wi-Fi identifiers (BSSID, ESSID, or SSID), Wi-Fi carrier information and Wi-Fi band (2.4, 5, and 60 GHz). The Wi- Fi measurement reporting is triggered using RSSI measurement. A Wi-Fi measurement report contains RSSI and Wi-Fi identifier and may contain Wi-Fi carrier information, Wi-Fi band, channel utilization, station count, admission capacity, backhaul rate, and an indication whether the UE is connected to the Wi-Fi [5]. The LTE and Wi-Fi integration architecture requires Wi-Fi-specific core network nodes and interfaces (as shown by dotted lines in Fig. 8.31). However, the LWA scheme is different vEPC/EPC PDCP aggregation and Circuit switch PDCP reordering (IMS) PDCP splitting Gy/Gz S1-MME LWA UE LTE Uu modem Wi-Fi IEEE 802.11 Wi-FiAl modem Gateway Figure 8.31 LWA network architecture (non-co-located case) [5,18]. Operation in Unlicensed and Shared Spectrum LWAUE Application TCP/UDP/IP LTE modem LTE Uu Wi-Fi modem LWAAP Wi-FiAP LWAAP GTP-L GTP-U IEEE 802.11 L1/L2 01/L2 LWAeNB Figure 8.32 LWA protocol architecture (non-co-located case, user-plane) [5,18]. because LTE and Wi-Fi are aggregated at the radio link level. The LWA protocol architec- ture, data aggregation at the PDCP sublayer, signaling and interfaces between eNB and Wi- Fi AP, etc., have been specified by 3GPP and