Interworking techniques and architectures for WLAN/3G integration toward 4G mobile data networks

Interworking of 3G cellular networks and wireless LANs

“…Currently, WLANs may be owned by a 3G operator, a commercial WLAN operator, an authority of a public hotspot (e.g., airports or property management corporations) or a business enterprise for internal use (Salkintzis, 2004). The interworking mechanisms are directly related to the ownership of WLANs.…”

“…The lines with tags 'a' and 'b' are examples for tight coupling with different integration points. Typical tight-coupling architectures include the first architecture proposed in Salkintzis et al (2004) and Buddhikot et al (2003b).…”

“…The second architecture proposed in Salkintzis et al (2004) and Buddhikot et al (2003b), respectively, and the operator WLAN system in Ala-Laurila et al (2001) belong to this category. This type of architecture imposes minimal requirements to modify current WLAN standards, and allows for the flexibility and independence of implementing individually different mechanisms within each network.…”

“…Considering the flexibility and interoperability requirement, AAA server is introduced in UMTS (3GPP, 2004b). By means of EAP-AKA, the 3G home AAA server authenticates the UMTS subscribers roaming to a WLAN through the UMTS AKA procedure (Ahmavaara et al, 2003;Buddhikot et al, 2003a;Koien and Haslestad, 2003;Salkintzis, 2004), while EAP-SIM can be used for legacy GSM/GPRS system (Ala-Laurila et al, 2001; Salkintzis et al, 2002). The authentication information and subscription profile can be retrieved from the Home Subscriber Server (HSS) or HLR.…”

“…The authenticator is responsible for relaying EAP frames sent by the supplicant via EAP-Over-LAN (EAPOL), and repacketing them into appropriate AAA messages for onward transmission to the authentication server, and vice versa. In the interworking mechanism, the functions of the authenticator can be carried by the AP (Salkintzis et al, 2004), the WLAN access router, or a separate WLAN AAA proxy (Salkintzis, 2004). A successful authentication procedure is summarised in Figure 2.…”