A (rather long) list of general requirements has been set up as guidelines for the standardization work related to the EPC. Some of those are:
• 3GPP and non-3GPP access systems shall be supported.
• Scalable system architecture and solutions without compromising the system capacity (e.g. by separating CP from UP).
• CP response time shall be such that the UE can move from an idle state to one where it is sending/receiving data in less than 200 ms.
• Basic IP connectivity is established during the initial access phase (hence, the UE is ‘always-on’).
• The Mobility Management (MM) solution shall be able to accommodate terminals with different mobility requirements (fixed, nomadic and mobile terminals).
• The MM functionality shall allow the network operator to control the type of access system being used by a subscriber.
• MM procedures shall provide seamless operation of both real-time (e.g. VoIP) and non real-time applications.
• In order to maximise users’ access opportunities, the architecture should allow a UE that is roaming to use a non-3GPP access (e.g. WLAN) network with which the VPLMN has a business agreement. For example, it should be possible for a user to use a WLAN access network with which only the visited operator has a direct relationship (not the home operator).
• The evolved system shall support Ipv4 and Ipv6 connectivity.
• Access to the evolved system shall be possible with R99 USIM. (Please note that this does not explicitly allow access using SIM)
• The authentication framework should be independent from the used access network technology.
• Radio interface multicast capability shall be a built-in feature.
• The SAE/LTE system shall support network-sharing functionality.
• It shall be possible to support service continuity between IMS over SAE/LTE access and the Circuit Switched (CS) domain.
• It shall be possible for the operator to provide the UE with access network information pertaining to locally supported 3GPP and non-3GPP access technologies.
Why Requirements on the EPC in LTE?
The Evolved Packet Core (EPC) plays a crucial role in the LTE network by ensuring efficient data handling, mobility management, and seamless service delivery. The requirements on the EPC are driven by the need for high-speed data transfer, low latency, scalability, and efficient resource management. Here’s why specific requirements are needed for the EPC in LTE:
- High Throughput: The EPC needs to support high data throughput to handle the increasing demand for mobile broadband services. It must be capable of processing large amounts of data quickly to deliver fast services to end-users.
- Low Latency: For real-time applications like VoLTE (Voice over LTE) and video streaming, low latency is critical. The EPC must ensure quick and efficient processing of signaling and data traffic to minimize delays.
- Scalability: The EPC must be scalable to accommodate a growing number of devices and users. It should be able to handle traffic spikes and support the addition of new users without compromising performance.
- Mobility Management: The EPC is responsible for managing user mobility across different networks and cell sites. It needs to handle seamless handovers and maintain ongoing sessions when a user moves between cells.
- Network Security: The EPC must support robust security protocols to protect user data and prevent unauthorized access. This includes encryption, authentication, and secure data transmission between network elements.
- Efficient Resource Management: The EPC must efficiently manage network resources such as bandwidth, IP addresses, and user sessions to ensure optimal performance and avoid congestion or overloading.
- Interoperability: The EPC must be interoperable with other networks (e.g., 3G, 2G) and technologies (e.g., Wi-Fi) to ensure smooth handoffs and service continuity for users.
In summary, the EPC in LTE is designed to meet specific requirements for high throughput, low latency, scalability, mobility, security, and efficient resource management to deliver a seamless, high-performance user experience.