t networks: traditional cellular networks, small cells integrating LTE and Wi-Fi accesses and stand-alone Wi-Fi access points. Given this variety, choosing the best network for a mobile is essential. The access network discovery and selection function (ANDSF) allows network detection and selection between LTE and Wi-Fi accesses. The rules defined by the 4G mobile network operator are provided by the ANDSF server, which is an optional element of the EPC core network. Hotspot 2.0 (HS2.0) is a working group of WFA. The target of the HS2.0 job is to facilitate the use of the Wi-Fi access point in a 4G mobile network. The HS2.0 certification program is called Passpoint. Introduction The key features of version 1 are based on the 802.11u standard and include additions to the access point beacon and the ANQP (Access Network Query Protocol) server that provides rules defined by the Wi-Fi service operator. Version 2 allows the mobile to identify the home operator and the partners that should be used when the home operator is not directly accessible. I.4. Wi-Fi and LTE access aggregation The integration of the Wi-Fi network to the 4G mobile network brings changes to the EPC core network, the anchor point being realized by the PGW entity. The aggregation of LTE and Wi-Fi channels is another approach that does not impact the structure of the EPC core network (Figure I.8). LTE access operates in a licensed frequency band. The LTE Advanced and LTE Advanced Pro evolutions, respectively, defined an aggregation of 5 and 32 LTE channels. The eNB entity is the anchor point for channel aggregation. LAA (Licensed Assisted Access) aggregation is an extension of LTE aggregation. The LTE transmission is performed on LTE and Wi-Fi frequency bands, between the mobile and the eNB entity, without an intermediate access point. The eNB entity is the anchor point for channel aggregation. LWA (LTE-Wi-Fi Aggregation) uses LTE and Wi-Fi frequency bands. Transmission over the Wi-Fi radio channel is between the mobile and the access point in accord