with the thresholds provided then guiding the WLAN selection. Solution 3 was based on the traffic steering for UEs in RRC CONNECTED state. The UEs would be controlled by the network using dedicated traffic steering commands, very similar to a handover operation (not just moving the actual connection but only part of the traffic). The solution would have been based on WLAN measurements from the UE done for the WLAN networks as defined by the eNodeB for UE to measure. The 3GPP concluded to focus on the actual specification for combination of solutions 1 and 2, with the Release 12 work mostly completed by September 2014 for the work item started [9]. The radio-level functionality in Release 12 allows to define different parameters for con- trolling the selection of WLAN (and thus giving guidance of when to come back to LTE), as shown on Figure 3.8. LTE Small Cell Optimization eNodeB 1. WLAN 3. Off-load bearer selection to WLAN when WLAN AP parameters via conditions are RRC signalling 2. Measure WLAN RSSI and LTE RSRQ/RSRP and decode WLAN AP beacon Figure 3.8 WLAN off-loading control from LTE eNodeB The following parameters are defined in Release 12 3GPP specifications, with part of them actually obtained either from the WLAN AP signalling or from the UE WLAN measurements: The offload preference indicator can be used to configure the UE whether there is preference to use WLAN for off-loading data or not. There are parameters on the available backhaul capacity (given in Kbps) in the WLAN AP. The two different thresholds for Backhaul for Downlink Bandwidth allow defining higher value based on which WLAN should be used and lower value based on which LTE should be used instead. This value is provided by WLAN AP. Respectively the parameters can be set for the uplink backhaul bandwidth as well. The parameter 'thresholdBeaconRSSI' gives two different values to avoid selecting WLAN AP with too low signal strength (or rather move back to LTE in such a case) and when WLAN AP RSSI is considered strong enough to move from LTE to