Evolved Packet System Architecture

Evolved Universal Mobile Telecommunication Systems Terrestrial Radio Access Network(E-UTRAN) is an air interface that allows the communication of radios between the cellphones and Evolved Packet Core(EPC) in the Long Term Evolution(LTE) networks as introduced by the 3rd Group Partnership Project(3GPP). Its components are the eNodeB(eNB), S1-U, S1-MME and X2 (Godor, Kovacs, & Racz, 2018). Evolved Packet Core(EPC) is a framework that converges voice and gives data on the Long Term Evolution(LTE) network which uses the Internet Protocol(IP) architecture as released by the 3GPP. Its components are the HSS, Serving GW, PDN GW and MME (Firmin, 2018).

Functionalities of the E-UTRAN

            The eNB is a base station for controlling the mobile in one cell. It sends and receives processed digital and analog radio transmission signals to the mobiles in the Long Term Evolution network. It also controls the mobile operations when the levels are low. The S1 interface connects the eNB to the Evolved Packet Core. The S1-U is the user plane interface connecting the eNB to the Serving GW of Evolved Packet Core. Lastly, the S1-MME is the control plane interface connecting the eNB to the MME of Evolved Packet Core. The X2 interface connects eNB to the base station which are near each other. It also forwards stored packets from the previous base station to another when the user moves from one place to another. This helps to minimize the loss of packets due to user movements (Godor, et al., 2018).

Functionalities of the EPC

            Home Subscriber Server(HSS) is the database containing information about the users. In addition, it provides support functions in authenticating users, setting up calls and authorization of access. Serving GW is an interconnection point between the user equipment(UE) and Evolved Packet Core. Its function is to route the incoming and outgoing IP data packets. Packet Data Network(PDN) GW is an interconnection point between external IP network and Evolved Packet Core. Its function is routing IP data packets in and out of the Packet Data Networks (Firmin, 2018). It also allocates an IP address. Mobility Management Entity ensures the E-UTRAN security access and signal handling during user movements. Moreover, it tracks the user equipment when it is idle and also the point of termination for the Non-Access Stratum.

E-UTRAN Architecture

            The E-UTRAN architecture (Figure 3.2) is a flatter and simple model. The purpose of the model is reducing the latency of interfacing the radio operations. It contains a single base station, eNodeB, interfacing with the user equipment(UE). The base stations link to each other through the X2 interface. They also link to the EPC through the S1 interface.

EPC Architecture

            The Evolved Packet Core architecture (Figure 3.1) is divided into the core network and access network. E-UTRAN is the access network and Evolved Packet Core is the core network. In addition, the packed switched IP core network is also the core network. The hops are few in the signal and data plane making the network less complex and reduces latency. The Evolved Packet Core also supports the non-3GPP access to the mobile IP through the addition of the Non-Access Stratum(NAS). NAS ensures there is the security of information, robust system and protection of integrity during the interworking of 3GPP and non- 3GPP network (Firmin,2018). The EPC and E-UTRAN are merged together to constitute the evolved packet system(EPS).

References

Firmin, F. (2018). The Evolved Packet Core. Retrieved 11, October 2018 from

http://www.3gpp.org/technologies/keywords-acronyms/100-the-evolved-packet-core

Godor, I., Kovacs, A., & Racz, A. (2018). U.S. Patent No. 9,866,919. Washington, DC: U.S.

Patent and Trademark Office.