1.1. Functional architecture
EPS (Evolved Packet System) is the name of the 4G mobile network. It consists of an evolved packet core (EPC) and an evolved universal terrestrial radio access network (E-UTRAN).
The E-UTRAN network presents the LTE (Long-Term Evolution) radio interface to the mobile.
Wi-Fi (Wireless Fidelity) interface is subsequently integrated into the EPS network and is a component of a set of technologies grouped under the term Non-3GPP Access.
Its introduction has an impact on the core network (EPC) architecture, which has several variants depending on the following characteristics:
- – Wi-Fi access is trusted or untrusted by the operator;
- – mobility is managed by the network or the mobile.
1.1.1. Architecture based on the S2a interface
The functional architecture based on the S2a interface corresponds to trusted Wi-Fi access and network-based mobility (Figure 1.1).
The mobile stream travels through the Wi-Fi radio interface and the S2a tunnel to access the packet data network (PDN). The PGW (PDN Gateway) entity is an IP (Internet Protocol) router that acts as a gateway for the mobile stream.
The home subscriber server (HSS) and the AAA (Authentication, Authorization and Accounting) server provide the following functions:
- – mutual authentication of the mobile ...