Long-Term Evolution (LTE) complements the success of HSPA with higher peak data rates, lower latency and an enhanced broadband example of high-demand areas. This is accomplished while using wider-spectrum bandwidths, OFDMA and SC-FDMA air interfaces, and advanced antenna techniques. These techniques enable high spectral efficiency and an excellent consumer experience for the lots of converged IP services. To take full benefit of these broadband access networks and let the co-existence of multiple technologies through an efficient, all-ip-packet architecture, 3GPP? implemented a new core network, the evolved packet core (EPC). EPC is planned for 3GPP Release 9 which is suitable for use by various access networks including LTE, HSPA/HSPA+ and non-3GPP networks. The evolved packet system (EPS) comprises the EPC and a number of access systems for example the eUTRAN or UTRAN. EPS have been designed through the start to aid seamless mobility and QoS with minimal latency for IP services.
EVOLVING ALL-IP FLAT ARCHITECTURE
The 3GPP is beginning to change wireless networks to become flatter and even more simplified. In EPS's user plane, for instance, you will find only two types of nodes (base stations and gateways), while in current hierarchical networks you will discover four types, together with a centralized RNC. Another simplification is the separation on the control plane, using a separate mobility-management network element. It can be worth noting that similar optimizations are enabled from the evolved HSPA network architecture, providing a likewise flattened architecture.
A vital difference from current networks is that the EPC is determined to guide packet-switched traffic only. Interfaces depend on IP protocols. This means that all services will probably be delivered through packet connections, including voice. Thus, EPS provides savings for operators with a single-packet network for all those services.
EVOLVED NODE-B (eNB)
A noticeable simple truth is that almost all in the typical protocols implemented in the current RNC are transferred to the eNB. The eNB, similar to the Node B functionality in the evolved HSPA architecture, can also be liable for header compression, ciphering and reliable delivery of packets. About the control plane, functions such as admission control and radio resource management will also be incorporated into the eNB. Benefits of the RNC and Node B merger include reduced latency with fewer hops on tv path, and distribution in the RNC processing load into multiple eNBs.
SERVING AND PDN GATEWAYS
Between access network and the PDNs (e.g., the online world), gateways keep the interfaces, the mobility needs along with the differentiation of QoS flows. EPS defines two logical gateway entities, the S-GW along with the P-GW. The S-GW provides a local mobility anchor, forwarding and receiving packets both to and from the eNB in which the UE has been served. The P-GW, in turn, interfaces using the external PDNs, such as the Internet and IMS. It is also to blame for several IP functions, like address allocation, policy enforcement, packet classification and routing, also it provides mobility anchoring for non-3GPP access networks. In practice, both gateways may be implemented united physical network element, according to deployment scenarios and vendor support.
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