4G Mobile Broadband - LTE Community Architecture and Protocol Stack

ABSTRCT

The objective of the LTE regular ?website is usually to generate specs for the new radio-access technologies geared to larger information prices, lower latency and larger spectral efficiency. The spectral efficiency focus on for the LTE procedure is 3 to 4 moments greater than the latest HSPA program. These intense spectral performance targets have to have making use of the technologies envelope by using innovative air-interface methods such as low-PAPR orthogonal uplink numerous entry based on SC-FDMA(single-carrier frequency division several entry) MIMO multiple-input multiple-output multi-antenna systems, inter-cell interference mitigation tactics, lower latency channel framework and single-frequency community (SFN) broadcast. The scientists and engineers working on the standard come up with new progressive technological innovation proposals and ideas for process efficiency enhancement. On account of the extremely intense regular development plan, these researchers and engineers are commonly not able to publish their proposals in conferences or journals, and so on. During the criteria advancement period, the proposals go through comprehensive scrutiny with several resources evaluating and simulating the proposed systems from system general performance enhancement and implementation complexity perspectives. Therefore, only the highest-quality proposals and concepts at last make to the conventional.

Key terms: LTE Architecture, UDP, GDP, MIMO, MIME, MCCH, MBMS, QOS

one. INTRODUCYION

The LTE network architecture is intended together with the goal of supporting packet-switched targeted visitors with seamless mobility, high-quality of services (QoS) and negligible latency. A packet-switched strategy will allow with the supporting of all solutions including voice as a result of packet connections. The end result within a really simplified flatter architecture with only two sorts of node namely advanced Node-B (eNB) and mobility administration entity/gateway (MME/GW). This is certainly in contrast to quite a few far more community nodes in the present-day hierarchical community architecture in the 3G method. A person main alter is the fact the radio community controller (RNC) is eliminated within the facts route and its features are now incorporated in eNB. A few of the benefits of a single node within the entry network are lessened latency plus the distribution of your RNC processing load into numerous eNBs. The elimination of the RNC within the accessibility community was attainable partly since the LTE procedure will not assistance macro-diversity or soft-handoff.

2. LTE Community ARCHITECTURE

Many of the community interfaces are dependant on IP protocols. The eNBs are interconnected by way of an X2 interface also to the MME/GW entity by way of an S1 interface as shown in Figure1. The S1 interface supports a many-to-many relationship amongst MME/GW and eNBs.

The functional split among eNB and MME/GW is shown in Determine 2 Two rational gateway entities specifically the serving gateway (S-GW) as well as the packet info network gateway (P-GW) is outlined. The S-GW acts as being a local mobility anchor forwarding and getting packets to and from your eNB serving the UE. The P-GW interfaces with external packet info networks (PDNs) such as the Net as well as IMS. The P-GW also performs several IP functions for instance address allocation, coverage enforcement, packet filtering and routing.

The MME is really a signaling only entity and therefore consumer IP packets do not experience MME. A benefit of a separate community entity for signaling is usually that the network capability for signaling and site visitors can grow independently. The most crucial functions of MME are idle-mode UE access potential including the command and execution of paging retransmission, monitoring place record administration, roaming, authentication, authorization, P-GW/S-GW selection, bearer administration which include focused bearer establishment, safety negotiations and NAS signaling, etc.

Advanced Node-B implements Node-B features and also protocols traditionally executed in RNC. The leading features of eNB are header compression, ciphering and reputable supply of packets. To the manage side, eNB incorporates features like admission command and radio resource management. Several of the advantages of a one node from the accessibility network are lowered latency and the distribution of RNC the community facet are now terminated in eNB.

Determine 1: Community Architecture

Determine two: Useful break up involving eNB and MME/GW.

two.1 PROTOCOL STACK AND CONYTOL Plane

The consumer plane protocol stack is offered in Figure 3.We notice that packet info convergence protocol (PDCP) and radio website link manage (RLC) levels usually terminated in RNC on Figure 4 reveals the handle airplane protocol stack.

Figure 3: Person airplane protocol.

Determine 4: Manage airplane protocol stack.

We notice that RRC performance ordinarily carried out in RNC is currently incorporated into eNB. The RLC and MAC layers execute precisely the same capabilities since they do for that consumer plane. The capabilities executed because of the RRC contain process data broadcast, paging, radio bearer handle, RRC connection administration, mobility features and UE measurement reporting and handle. The non-access stratum (NAS) protocol terminated from the MME to the network side and in the UE within the terminal facet performs capabilities including EPS (advanced packet system) bearer administration, authentication and protection command, etc.

The S1 and X2 interface protocol stacks are proven in Figures 2.five and a pair of.6 respectively.We observe that equivalent protocols are applied on both of these interfaces. The S1 person plane interface (S1-U) is outlined involving the eNB plus the S-GW. The S1-U interface utilizes GTP-U (GPRS tunneling protocol - user details tunneling) on UDP/IP transport and offers non-guaranteed supply of user airplane PDUs in between the eNB as well as the S-GW. The GTP-U is really a rather simple IP based tunneling protocol that allows a lot of tunnels between each individual list of conclusion points. The S1 handle aircraft interface (S1-MME) is described as getting amongst the eNB as well as the MME. Comparable to the consumer plane, the transport community layer is constructed on IP transport and for the reliable