multaneously on several elements of ANQP information. The information element HS Query List is transmitted in a GAS Query Request frame. Network Discovery and Selection 10.2.2.15. HS Capability List element The information element HS Capability List tells the mobile which ANQP elements are supported by the access point. The information element HS Capability List is transmitted in a GAS Query Response frame. 10.2.2.16. NAI Home Realm Query element The information element NAI Home Realm Query enables the mobile to determine whether the domains for which it has security information correspond to the service providers whose networks are accessible at the access point. Carrier Aggregation 11.1. Functional architecture The integration of Wi-Fi technology into the 4G mobile network results in the sharing of sessions between LTE (Long-Term Evolution) access (e.g. VoLTE session) and Wi-Fi access (e.g. Internet session). The aggregation of LTE and Wi-Fi access is done at the PDN gateway (PDN). The consideration of Wi-Fi access impacts the architecture of the evolved packet core (EPC). The aggregation of the carriers results in a sharing of the IP (Internet Protocol) packets between the different accesses. For the downstream direction (respectively the upstream direction), the sharing is performed by the evolved node B station (eNB) (respectively the mobile) and the reassembly is provided by the mobile (respectively the entity eNB). This operation is performed exclusively in the enhanced universal terrestrial radio access network (E-UTRAN) and does not impact the EPC network (Figure 11.1). LTE and Wi-Fi carrier aggregation can be implemented with collocated or remote eNB and AP (Access Point) entities. The Xw interface is the point of reference between the eNB and AP entities when they are distant (Figure 11.1). Wi-Fi Integration to the 4G Mobile Network, First Edition. André Perez. C ISTE Ltd 2018. Published by ISTE Ltd and John Wiley & Sons, Inc. 202 Wi-Fi Integration to the 4G Mobile Network E-UTRAN LTE-Uu S1-MMF Wi-Fi L