4G Cellular Broadband - LTE Network Architecture and Protocol Stack

ABSTRCT

The intention with the LTE typical ?defense pdu would be to generate specs for any new radio-access technological know-how geared to better information prices, reduced latency and greater spectral efficiency. The spectral effectiveness concentrate on for that LTE technique is a few to 4 occasions larger than the current HSPA technique. These intense spectral effectiveness targets have to have utilizing the know-how envelope by employing state-of-the-art air-interface approaches for instance low-PAPR orthogonal uplink several access determined by SC-FDMA(single-carrier frequency division numerous entry) MIMO multiple-input multiple-output multi-antenna technologies, inter-cell interference mitigation methods, lower latency channel composition and single-frequency network (SFN) broadcast. The researchers and engineers engaged on the standard occur up with new revolutionary engineering proposals and concepts for method effectiveness improvement. As a result of the very aggressive regular growth agenda, these researchers and engineers are commonly not able to publish their proposals in conferences or journals, etcetera. In the specifications growth stage, the proposals endure in depth scrutiny with numerous resources evaluating and simulating the proposed technologies from technique effectiveness enhancement and implementation complexity views. For that reason, just the highest-quality proposals and concepts last but not least make to the typical.

Keywords: LTE Architecture, UDP, GDP, MIMO, MIME, MCCH, MBMS, QOS

one. INTRODUCYION

The LTE network architecture is made with all the intention of supporting packet-switched targeted visitors with seamless mobility, high quality of provider (QoS) and negligible latency. A packet-switched method makes it possible for for the supporting of all products and services such as voice through packet connections. The result in the highly simplified flatter architecture with only two types of node namely evolved Node-B (eNB) and mobility management entity/gateway (MME/GW). This really is in distinction to a lot of extra community nodes from the present-day hierarchical community architecture on the 3G method. Just one big change is the fact that the radio community controller (RNC) is eliminated with the information path and its capabilities are now incorporated in eNB. Many of the advantages of the solitary node while in the accessibility network are diminished latency as well as the distribution on the RNC processing load into multiple eNBs. The elimination on the RNC from the obtain community was possible partly simply because the LTE technique isn't going to aid macro-diversity or soft-handoff.

two. LTE Network ARCHITECTURE

All of the network interfaces are based on IP protocols. The eNBs are interconnected by the use of an X2 interface and also to the MME/GW entity via an S1 interface as proven in Figure1. The S1 interface supports a many-to-many romance between MME/GW and eNBs.

The functional split between eNB and MME/GW is demonstrated in Determine 2 Two logical gateway entities namely the serving gateway (S-GW) plus the packet facts community gateway (P-GW) is described. The S-GW acts for a regional mobility anchor forwarding and obtaining packets to and from the eNB serving the UE. The P-GW interfaces with external packet knowledge networks (PDNs) such as the World wide web and also the IMS. The P-GW also performs a number of IP features for example deal with allocation, coverage enforcement, packet filtering and routing.

The MME is really a signaling only entity and therefore person IP packets tend not to undergo MME. A benefit of a different community entity for signaling is the fact the network potential for signaling and targeted visitors can grow independently. The key capabilities of MME are idle-mode UE reach skill such as the control and execution of paging retransmission, tracking spot list management, roaming, authentication, authorization, P-GW/S-GW choice, bearer administration like committed bearer institution, stability negotiations and NAS signaling, and so forth.

Progressed Node-B implements Node-B features and also protocols customarily applied in RNC. The most crucial functions of eNB are header compression, ciphering and trusted delivery of packets. To the command facet, eNB incorporates capabilities for instance admission management and radio useful resource administration. Some of the benefits of a one node in the accessibility network are diminished latency along with the distribution of RNC the network side are actually terminated in eNB.

Figure one: Community Architecture

Determine 2: Practical split in between eNB and MME/GW.

2.1 PROTOCOL STACK AND CONYTOL Plane

The person plane protocol stack is provided in Figure 3.We observe that packet knowledge convergence protocol (PDCP) and radio backlink management (RLC) levels ordinarily terminated in RNC on Determine four displays the command airplane protocol stack.

Figure 3: User airplane protocol.

Figure 4: Control airplane protocol stack.

We take note that RRC operation historically applied in RNC is now incorporated into eNB. The RLC and MAC levels complete the same functions because they do to the person airplane. The capabilities performed by the RRC include things like process facts broadcast, paging, radio bearer manage, RRC connection management, mobility functions and UE measurement reporting and handle. The non-access stratum (NAS) protocol terminated while in the MME on the community facet and in the UE to the terminal facet performs functions including EPS (advanced packet technique) bearer management, authentication and security handle, and so on.

The S1 and X2 interface protocol stacks are proven in Figures 2.five and 2.6 respectively.We be aware that similar protocols are utilized on both of these interfaces. The S1 user aircraft interface (S1-U) is outlined among the eNB and also the S-GW. The S1-U interface works by using GTP-U (GPRS tunneling protocol - person info tunneling) on UDP/IP transportation and provides non-guaranteed shipping of user airplane PDUs involving the eNB plus the S-GW. The GTP-U can be a somewhat basic IP primarily based tunneling protocol that permits numerous tunnels involving each set of stop factors. The S1 manage aircraft interface (S1-MME) is defined as becoming between the eNB along with the MME. Comparable to the user airplane, the transportation network layer is developed on IP transportation and for that reliable