Inter-system mobility in evolved packet system (EPS): Connecting non-3GPP accesses

EPS (Evolved Packet System) was designed with a new radio access network LTE (Long Term Evolution). But EPS also supports natively non-3GPP accesses with associated QoS (Quality of Service), security and mobility requirements. Although the initial EPS deployment would be with the introduction of LTE for providing higher data rate, operators would still need to introduce non-3GPP accesses, e.g. WiFi, WiMAX, etc. in EPS for various reasons, most notably to cope with “data tsunami” and reduce the cost per bit in their network. In this context, EPS has to consider that different non-3GPP accesses possess different characteristics in terms of security, bandwidth and tariffs. Moreover, EPS mobility management mechanism has to provide mobility support for non-3GPP accesses, which can be based on either client-based mobility protocol (e.g. Dual Stack Mobile IPv6 - DSMIPv6) or network-based mobility protocol (e.g. Proxy Mobile IPv6 - PMIPv6). This paper discusses various technical issues related to the migration of non-3GPP accesses in EPS.