Following are the main targets for SAE design:
- High-level user and operational aspects,
- Basic capabilities,
- Multi-access and seamless mobility,
- Man–machine interface aspects,
- Performance requirements for the evolved 3GPP system,
- Security and privacy, and
- Charging aspects.
Although the SAE requirements are many and split into the subgroups above, but as seen from the above points the SAE requirements are mainly non-radio access related.
The SAE system should be able to operate with more than the LTE radio access network and there should be mobility functions allowing a mobile terminal to move between the different radio-access systems. In fact, the requirements do not limit the mobility between radio access networks, but opens up for mobility to fixed-access network. The access networks need not to be developed by 3GPP, other non-3GPP access networks should also be considered. Thus the implementation for SAE should cover classes or functions for each handovers where the functions can be called as mobility functions.
The SAE requirements also list performance as an essential requirement but do not go into the same level of details as the LTE requirements. Different traffic scenarios and usage are envisioned, for example user to user and user to group communication. Furthermore, resource efficiency is required, especially radio resource efficiency (spectrum efficiency requirement for LTE). The SAE resource efficiency requirement is not as elaborated as the LTE requirement.
Thus it is the LTE requirement that is the design requirement.
Of course, the SAE requirements address the service aspects and require that the traditional services such as voice, video, messaging, and data file exchange should be supported, and in addition multicast and broadcast services. In fact, with the requirement to support IPv4 and IPv6 connectivity, including mobility between access networks supporting different IP versions as well as communication between terminals using different versions, any service based on IP will be supported
There is quality of service requirement of SAE is SAE system should for example, provide no perceptible deterioration of audio quality of a voice call during and following handover between dissimilar circuit switched and packet-switched access networks. Furthermore, the SAE should ensure that there is no loss of data as a result of a handover between dissimilar fixed and mobile access systems. A particular important requirement for the SAE QoS concept is that the SAE QoS concept should be backwards compatible with the pre- SAE QoS concepts of 3GPP. This is to ensure smooth mobility between different 3GPP accesses (LTE, WCDMA/HSPA and GSM).
The SAE system should provide advanced security mechanisms that are equivalent to or better than 3GPP security for WCDMA/HSPA and GSM. This means that protection against threats and attacks including those present on the Internet should be part of SAE. Furthermore, the SAE system should provide information authenticity between the mobile terminal and the network, but at the same time enable lawful interception of the traffic.
The SAE system has strong requirements on user privacy. Several levels of user privacy should be provided, for example communication confidentiality, location privacy, and identity protection. Thus, SAE -based systems will hide the identity of the users from unauthorized third parties, protect the content, origin and destination of a particular communication from unauthorized parties, and protect the location of the user from unauthorized parties. Authorized parties are normally government agencies, but the user may give certain parties the right to know about the location of the mobile terminal. One example hereof is fleet management for truck dispatchers.
Several charging models, including calling party pays, flat rate, and charging based on QoS is required to be supported in SAE. Charging aspects are sometimes visible in the radio access networks, especially those charging models that are based on delivered QoS or delivered data volumes. However, most charging schemes are only looking at information available in the core network.