4G Mobile Broadband – LTE Network Architecture and Protocol Stack

ABSTRCT

The aim of the LTE normal is to create specs for a brand new radio-entry expertise geared to increased knowledge charges, low latency and larger spectral effectivity. The spectral effectivity goal for the LTE system is three to 4 occasions increased than the present HSPA system. These aggressive spectral effectivity targets require utilizing the expertise envelope by using superior air-interface strategies corresponding to low-PAPR orthogonal uplink a number of entry primarily based on SC-FDMA(single-provider frequency division a number of entry) MIMO a number of-enter a number of-output multi-antenna applied sciences, inter-cell interference mitigation strategies, low latency channel construction and single-frequency community (SFN) broadcast. The researchers and engineers engaged on the usual give you new revolutionary expertise proposals and concepts for system efficiency enchancment. As a result of extremely aggressive normal growth schedule, these researchers and engineers are typically unable to publish their proposals in conferences or journals, and many others. Within the requirements growth part, the proposals undergo in depth scrutiny with a number of sources evaluating and simulating the proposed applied sciences from system efficiency enchancment and implementation complexity views. Subsequently, solely the very best-high quality proposals and concepts lastly make into the usual.

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

1. INTRODUCYION

The LTE community structure is designed with the aim of supporting packet-switched visitors with seamless mobility, high quality of service (QoS) and minimal latency. A packet-switched strategy permits for the supporting of all providers together with voice by means of packet connections. The end in a extremely simplified flatter structure with solely two sorts of node specifically developed Node-B (eNB) and mobility administration entity/gateway (MME/GW). That is in distinction to many extra community nodes within the present hierarchical community structure of the 3G system. One main change is that the radio community controller (RNC) is eradicated from the information path and its capabilities are actually integrated in eNB. A few of the advantages of a single node within the entry community are lowered latency and the distribution of the RNC processing load into a number of eNBs. The elimination of the RNC within the entry community was attainable partly as a result of the LTE system doesn’t assist macro-range or smooth-handoff.

2. LTE NETWORK ARCHITECTURE

All of the community interfaces are primarily based on IP protocols. The eNBs are interconnected via an X2 interface and to the MME/GW entity via an S1 interface as proven in Figure1. The S1 interface helps a many-to-many relationship between MME/GW and eNBs.

The purposeful cut up between eNB and MME/GW is proven in Determine 2 Two logical gateway entities specifically the serving gateway (S-GW) and the packet knowledge community gateway (P-GW) is outlined. The S-GW acts as an area mobility anchor forwarding and receiving packets to and from the eNB serving the UE. The P-GW interfaces with exterior packet knowledge networks (PDNs) such because the Web and the IMS. The P-GW additionally performs a number of IP capabilities corresponding to handle allocation, coverage enforcement, packet filtering and routing.

The MME is a signaling solely entity and therefore person IP packets don’t undergo MME. A bonus of a separate community entity for signaling is that the community capability for signaling and visitors can develop independently. The principle capabilities of MME are idle-mode UE attain capacity together with the management and execution of paging retransmission, monitoring space listing administration, roaming, authentication, authorization, P-GW/S-GW choice, bearer administration together with devoted bearer institution, safety negotiations and NAS signaling, and many others.

Advanced Node-B implements Node-B capabilities in addition to protocols historically applied in RNC. The principle capabilities of eNB are header compression, ciphering and dependable supply of packets. On the management aspect, eNB incorporates capabilities corresponding to admission management and radio useful resource administration. A few of the advantages of a single node within the entry community are lowered latency and the distribution of RNC the community aspect are actually terminated in eNB.

Determine 1: Network Architecture

Determine 2: Practical cut up between eNB and MME/GW.

2.1 PROTOCOL STACK AND CONYTOL PLANE

The person airplane protocol stack is given in Determine 3.We word that packet knowledge convergence protocol (PDCP) and radio hyperlink management (RLC) layers historically terminated in RNC on Determine 4 exhibits the management airplane protocol stack.

Determine 3: Person airplane protocol.

Determine 4: Management airplane protocol stack.

We word that RRC performance historically applied in RNC is now integrated into eNB. The RLC and MAC layers carry out the identical capabilities as they do for the person airplane. The capabilities carried out by the RRC embody system data broadcast, paging, radio bearer management, RRC connection administration, mobility capabilities and UE measurement reporting and management. The non-entry stratum (NAS) protocol terminated within the MME on the community aspect and on the UE on the terminal aspect performs capabilities corresponding to EPS (developed packet system) bearer administration, authentication and safety management, and many others.

The S1 and X2 interface protocol stacks are proven in Figures 2.5 and 2.6 respectively.We word that comparable protocols are used on these two interfaces. The S1 person airplane interface (S1-U) is outlined between the eNB and the S-GW. The S1-U interface makes use of GTP-U (GPRS tunneling protocol – person knowledge tunneling) on UDP/IP transport and supplies non-assured supply of person airplane PDUs between the eNB and the S-GW. The GTP-U is a comparatively easy IP primarily based tunneling protocol that allows many tunnels between every set of finish factors. The S1 management airplane interface (S1-MME) is outlined as being between the eNB and the MME. Much like the person airplane, the transport community layer is constructed on IP transport and for the dependable

Determine 5: S1 interface person and management planes.

Determine 6: X2 interface person and management planes.

Transport of signaling messages SCTP (stream management transmission protocol) is used on high of IP The SCTP protocol operates analogously to TCP guaranteeing dependable, in-sequence transport of messages with congestion management. The appliance layer signaling protocols are known as S1 utility protocol (S1-AP) and X2 utility protocol (X2-AP) for S1 and X2 interface management planes respectively.

3. QOS AND BEARER SERVICE ARCHITECTURE

Functions corresponding to VoIP, internet searching, video telephony and video streaming have particular QoS wants. Subsequently, an essential function of any all-packet community is the availability of a QoS mechanism to allow differentiation of packet flows primarily based on QoS necessities. In EPS, QoS flows referred to as EPS bearers are established between the UE and the P-GW as proven in Determine 7. A radio bearer transports the packets of an EPS bearer between a UE and an eNB. Every IP movement (e.g. VoIP) is related to a distinct EPS bearer and the community can prioritize visitors accordingly.

Determine 7: EPS bearer service structure.

When receiving an IP packet from the Web, P-GW performs packet classification primarily based on sure predefined parameters and sends it an applicable EPS bearer. Primarily based on the EPS bearer, eNB maps packets to the suitable radio QoS bearer. There may be one-to-one mapping between an EPS bearer and a radio bearer.

4. LAYER 2 STRUCTURE

The layer 2 of LTE consists of three sub layers specifically medium entry management, radio hyperlink management (RLC) and packet knowledge convergence protocol (PDCP). The service entry level (SAP) between the bodily (PHY) layer and the MAC sub layer present the transport channels whereas the SAP between the MAC and RLC sub layers present the logical channels. The MAC sub layer performs multiplexing of logical channels on to the transport channels.

The downlink and uplink layer 2 constructions are given in Figures 8 and 9 respectively. The distinction between downlink and uplink constructions is that within the downlink, the MAC sub layer additionally handles the precedence amongst UEs along with precedence dealing with among the many logical channels of a single UE. The opposite capabilities carried out by the MAC sub layers in each downlink and uplink embody mapping between the logical and the transport channels.

Multiplexing of RLC packet knowledge items (PDU), padding, transport format choice and hybrid ARQ (HARQ).

The principle providers and capabilities of the RLC sub layers embody segmentation, ARQ in-sequence supply and duplicate detection, and many others. The in-sequence supply of higher layer PDUs isn’t assured at handover. The reliability of RLC might be configured to both acknowledge mode (AM) or un-acknowledge mode (UM) transfers. The UM mode can be utilized for radio bearers that may tolerate some loss. In AM mode, ARQ performance of RLC Retransmits transport blocks that fail restoration by HARQ. The restoration at HARQ could fail attributable to hybrid ARQ NACK to ACK error or as a result of the utmost variety of retransmission makes an attempt is reached. On this case, the related transmitting ARQ entities are notified and potential retransmissions and re-segmentation might be initiated.

Determine 8: Downlink layer 2 construction.

Determine 9: Uplink layer 2 construction.

The PDCP layer performs capabilities corresponding to header compression and decompression, ciphering and in-sequence supply and duplicate detection at handover for RLCAM, and many others. The header compression and decompression is carried out utilizing the sturdy header compression (ROHC) protocol. 5.1 Downlink logical, transport and bodily channels

4.1 DOWNLINK LOGICAL, TRANSPORT AND PHYSICAL CHANNELS

The connection between downlink logical, transport and bodily channels is proven in Determine 10. A logical channel is outlined by the kind of data it carriers. The logical channels are additional divided into management channels and visitors channels. The management channels carry management-airplane data, whereas visitors channels carry person-airplane data.

Within the downlink, 5 management channels and two visitors channels are outlined. The downlink management channel used for paging data switch is known as the paging management channel (PCCH). This channel is used when the community has no data in regards to the location cell of the UE. The channel that carries system management data is known as the printed management channel (BCCH). Two channels specifically the frequent management channel (CCCH) and the devoted management channel (DCCH) can carry data between the community and the UE. The CCCH is used for UEs that haven’t any RRC connection whereas DCCH is used for UEs which have an RRC connection. The management channel used for the transmission of MBMS management data is known as the multicast management channel (MCCH). The MCCH is utilized by solely these UEs receiving MBMS.

The 2 visitors channels within the downlink are the devoted visitors channel (DTCH) and the multicast visitors channel (MTCH). A DTCH is a degree-to-level channel devoted to a single UE for the transmission of person data. An MTCH is a degree-to-multipoint channel used for the transmission of person visitors to UEs receiving MBMS. The paging management channel is mapped to a transport channel known as paging channel (PCH). The PCH helps discontinuous reception (DRX) to allow UE energy saving. A DRX cycle is indicated to the UE by the community. The BCCH is mapped to both a transport channel known as a broadcast channel (BCH) or to the downlink shared channel (DLSCH).

Determine 10: Downlink logical, transport and bodily channels mapping.

The BCH is characterised by a hard and fast pre-outlined format as that is the primary channel UE receives after buying synchronization to the cell. The MCCH and MTCH are both mapped to a transport channel referred to as a multicast channel (MCH) or to the downlink shared channel (DL-SCH). The MCH helps MBSFN combining of MBMS transmission from a number of cells. The opposite logical channels mapped to DL-SCH embody CCCH, DCCH and DTCH. The DL-SCH is characterised by assist for adaptive modulation/coding, HARQ, energy management, semi-static/dynamic useful resource allocation, DRX, MBM Transmission and multi antenna applied sciences. All of the 4-downlink transport channels have the requirement to be broadcast in your entire protection space of a cell.

The BCH is mapped to a bodily channel known as bodily broadcast channel (PBCH), which is transmitted over 4 sub frames with 40 ms timing interval. The 40 ms timing is detected blindly with out requiring any express signaling. Additionally, every sub body transmission of BCH is self-decodable and UEs with good channel situations could not want to attend for reception of all of the 4 sub frames for PBCH decoding. The PCH and DL-SCH are mapped to a bodily channel known as bodily downlink shared channel (PDSCH). The multicast channel (MCH) is mapped to bodily multicast channel (PMCH), which is the multi-cell MBSFN transmission channel.

The three stand-alone bodily management channels are the bodily management format indicator channel (PCFICH), the bodily downlink management channel (PDCCH) and the bodily hybrid ARQ indicator channel (PHICH). The PCFICH is transmitted each sub body and carries data on the variety of OFDM symbols used for PDCCH. The PDCCH is used to tell the UEs in regards to the useful resource allocation of PCH and DL-SCH in addition to modulation, coding and hybrid ARQ data associated to DL-SCH. A most of three or 4 OFDM symbols can be utilized for PDCCH. With dynamic indication of variety of OFDM symbols used for PDCCH by way of PCFICH, the unused OFDM symbols among the many three or 4 PDCCH OFDM symbols can be utilized for knowledge transmission. The PHICH is used to hold hybrid ARQ ACK/NACK for uplink transmissions.

4.2 UPLINK LOGICAL, TRANSPORT AND PHYSICAL CHANNELS

The connection between uplink logical, transport and bodily channels is proven in Determine 2.11. Within the uplink two management channels and a single visitors channel is outlined. As for the downlink, frequent management channel (CCCH) and devoted management channel (DCCH) are used to hold data between the community and the UE. The CCCH is used for UEs having no RRC connection whereas DCCH is used for UEs having an RRC connection. Much like downlink, devoted visitors channel (DTCH) is a degree-to-level channel devoted to a single UE for transmission of person data. All of the three uplink logical channels are mapped to a transport channel named uplink shared channel (UL-SCH). The UL-SCH helps adaptive modulation/coding, HARQ, energy management and semi-static/dynamic useful resource allocation.

One other transport channel outlined for the uplink is known as the random entry channel (RACH), which can be utilized for transmission of restricted management data from a UE with chance of collisions with transmissions from different UEs. The RACH is mapped to bodily random entry channel (PRACH), which carries the random entry preamble.

The UL-SCH transport channel is mapped to bodily uplink shared channel (PUSCH). A stand-alone uplink bodily channel known as bodily uplink management channel (PUCCH) is used to hold downlink channel high quality indication (CQI) stories, scheduling request (SR) and hybrid ARQ ACK/NACK for downlink transmissions.

5. PROTOCOL STATES AND STATES TRANSITIONS

Within the LTE system, two radio useful resource management (RRC) states specifically RRC IDLE and RRC CONNECTED states are outlined as depicted in Determine 2.12. A UE strikes from RRC IDLE state to RRC CONNECTED state when an RRC connection is efficiently established. A UE can transfer again from RRC CONNECTED to RRC IDLE state by releasing the RRC connection. Within the RRC IDLE state, UE can obtain broadcast/multicast knowledge, displays a paging channel to detect incoming calls, performs neighbor cell measurements and cell choice/reselection and acquires system data. Moreover, within the RRC IDLE state, a UE particular DRX (discontinuous reception) cycle could also be configured by higher layers to allow UE energy financial savings. Additionally, mobility is managed by the UE within the RRC IDLE

State.

Within the RRC CONNECTED state, the switch of uncast knowledge to/from UE, and the switch of broadcast or multicast knowledge to UE can happen. At decrease layers, the UE could also be configured with a UE particular DRX/DTX (discontinuous transmission). Moreover, UE displays management channels related to the shared knowledge channel to find out if knowledge is scheduled for it, supplies channel high quality suggestions data, performs neighbor cell measurements and measurement reporting and acquires system data. Not like the RRC IDLE state, the mobility is managed by the community on this state.

Determine 11 Uplink logical, transport and bodily channels mapping.

Determine 12: UE states and state transitions.

6. SEAMLESS MOBILITY SUPPORT

An essential function of a cellular wi-fi system corresponding to LTE is assist for seamless mobility throughout eNBs and throughout MME/GWs. Quick and seamless handovers (HO) is especially essential for delay-delicate providers corresponding to VoIP. The handovers happen extra continuously throughout eNBs than throughout core networks as a result of the world coated by MME/GW serving numerous eNBs is mostly a lot bigger than the world coated by a single eNB. The

signaling on X2 interface between eNBs is used for handover preparation. The S-GW acts as anchor for inter-eNB handovers.

Within the LTE system, the community depends on the UE to detect the neighboring cells for handovers and due to this fact no neighbor cell data is signaled from the community. For the search and measurement of inter-frequency neighboring cells, solely the provider frequencies have to be indicated. An instance of lively handover in an RRC CONNECTED state is proven in Determine 13 the place a UE strikes from the protection space of the supply eNB (eNB1) to the protection space of the goal eNB (eNB2). The handovers within the RRC CONNECTED state are community managed and assisted by the UE. The UE sends a radio measurement report back to the supply eNB1 indicating that the sign high quality on eNB2 is best than the sign high quality on eNB1. As preparation for handover, the supply eNB1 sends the coupling data and the UE context to the goal eNB2 (HO request) [6] on the X2 interface. The goal eNB2 could carry out admission management depending on the acquired EPS bearer QoS data. The goal eNB configures the required sources in accordance with the acquired EPS bearer QoS data and reserves a C-RNTI (cell radio community momentary identifier) and optionally a RACH preamble.

Determine 13: Energetic handovers.

The C-RNTI supplies a singular UE identification on the cell stage figuring out the RRC connection. When eNB2 alerts to eNB1 that it is able to carry out the handover by way of HO response message, eNB1 instructions the UE (HO command) to vary the radio bearer to eNB2. The UE receives the HO command with the required parameters (i.e. new C-RNTI, optionally devoted RACH preamble, attainable expiry time of the devoted RACH preamble, and many others.) and is commanded by the supply eNB to carry out the HO. The UE doesn’t must delay the handover execution for delivering the HARQ/ARQ responses to supply eNB.

After receiving the HO command, the UE performs synchronization to the goal eNB and accesses the goal cell by way of the random entry channel (RACH) following a competition-free process if a devoted RACH preamble was allotted within the HO command or following a competition-primarily based process if no devoted preamble was allotted. The community responds with uplink useful resource allocation and timing advance to be utilized by the UE. When the UE has efficiently accessed the goal cell, the UE sends the HO verify message (C-RNTI) together with an uplink buffer standing report indicating that the handover process is accomplished for the UE. After receiving the HO verify message, the goal eNB sends a path change message to the MME to tell that the UE has modified cell. The MME sends a person airplane replace message to the S-GW. The S-GW switches the downlink knowledge path to the goal eNB and sends a number of “finish marker” packets on the previous path to the supply eNB and then releases any person-airplane/TNL sources in the direction of the supply eNB. Then S-GW sends a person airplane replace response message to the MME. Then the MME confirms the trail change message from the goal eNB with the trail change response message. After the trail change response message is acquired from the MME, the goal eNB informs success of HO to the supply eNB by sending launch useful resource message to the supply eNB and triggers the discharge of sources. On receiving the discharge useful resource message, the supply eNB can launch radio and C-airplane associated sources related to the UE context.

Throughout handover preparation U-airplane tunnels might be established between the supply ENB and the goal eNB. There may be one tunnel established for uplink knowledge forwarding and one other one for downlink knowledge forwarding for every EPS bearer for which knowledge forwarding is utilized. Throughout handover execution, person knowledge might be forwarded from the supply eNB to the goal eNB. Forwarding of downlink person knowledge from the supply to the goal eNB ought to happen so as so long as packets are acquired on the supply eNB or the supply eNB buffer is exhausted.

For mobility administration within the RRC IDLE state, idea of monitoring space (TA) is launched. A monitoring space typically covers a number of eNBs as depicted in Determine 2.14. The monitoring space id (TAI) data indicating which TA an eNB belongs to is broadcast as a part of system data. A UE can detect change of monitoring space when it receives a distinct TAI than in its present cell. The UE updates the MME with its new TA data because it strikes throughout TAs. When P-GW receives knowledge for a UE, it buffers the packets and queries the MME for the UE’s location. Then the MME will web page the UE in its most present TA. A UE might be registered in a number of TAs concurrently. This permits energy saving on the UE underneath situations of excessive mobility as a result of it doesn’t must continually replace its location with the MME. This function additionally minimizes load on TA boundaries.

8. MULTICAST BROADCAST SYSTEM ARCHITECTURE

Within the LTE system, the MBMS both use a single-cell transmission or a multi-cell transmission. In single-cell transmission, MBMS is transmitted solely within the protection of a particular cell and due to this fact combining MBMS transmission from a number of cells isn’t supported. The only-cell MBMS transmission is carried out on DL-SCH and therefore makes use of the identical community structure because the unicast visitors.

Determine 14: Monitoring space replace for UE in RRC IDLE state.

The MTCH and MCCH are mapped on DL-SCH for level-to-multipoint transmission and scheduling is finished by the eNB. The UEs might be allotted devoted uplink suggestions channels similar to these utilized in unicast transmission, which allows HARQ ACK/NACK and CQI suggestions. The HARQ retransmissions are made utilizing a gaggle (service particular) RNTI (radio community momentary identifier) in a timeframe that’s co-ordinated with the unique MTCH transmission. All UEs receiving MBMS are in a position to obtain the retransmissions and mix with the unique transmissions on the HARQ stage. The UEs which are allotted a devoted uplink suggestions channel are in RRC CONNECTED state. To be able to keep away from pointless MBMS transmission on MTCH in a cell the place there isn’t a MBMS person, community can detect presence of customers within the MBMS service by polling or by means of UE service request.

The multi-cell transmission for the developed multimedia broadcast multicast service (MBMS) is realized by transmitting similar waveform on the similar time from a number of cells. On this case, MTCH and MCCH are mapped on to MCH for level-to-multipoint transmission. This multi-cell transmission mode is known as multicast broadcast single frequency community (eMBSFN) as described intimately in Chapter 17. An MBSFN transmission from a number of cells inside an MBSFN space is seen as a single transmission by the UE. An MBSFN space includes a gaggle of cells inside an MBSFN synchronization space of a community which are co-ordinate to realize MBSFN transmission. An MBSFN synchronization space is outlined as an space of the community wherein all eNBs might be synchronized and carry out MBSFN transmission. An MBMS service space could encompass a number of MBSFN areas. A cell inside an MBSFN synchronization space could type a part of a number of SFN areas every characterised by completely different content material and set of taking part cells.

Determine 15. The eMBMS service space and MBSFN areas.

An instance of MBMS service space consisting of two MBSFN areas, space A and space B, is depicted in Determine 2.15. The MBSFNA space consists of cells A1-A5, cell AB1 and AB2. The MBSFN space consists of cells B1-B5, cell AB1 and AB2. The cells AB1 and AB2 are a part of each MBSFN space A and space B. The cell B5 is a part of space B however doesn’t contribute to MBSFN transmission. Such a cell is known as MBSFN space reserved cell. The MBSFN space reserved cell could also be allowed to transmit for different providers on the sources allotted for the MBSFN however at a restricted energy. The MBSFN synchronization space, the MBSFN space and reserved cells might be semi-statically configured by O&M.

The MBMS structure for multi-cell transmission is depicted in Determine 2.16. The multicell multicast coordination entity (MCE) is a logical entity, which suggests it may also be a part of one other community aspect corresponding to eNB. The MCE performs capabilities such because the allocation of the radio sources utilized by all eNBs within the MBSFN space in addition to figuring out the radio configuration together with the modulation and coding scheme. The MBMS GW can be a logical entity whose predominant operate is sending/broadcasting MBMS packets with the SYNC protocol to every eNB transmitting the service. The MBMS GW hosts the PDCP layer of the person airplane and makes use of IP multicast for forwarding MBMS person knowledge to eNBs.

The eNBs are related to eMBMS GW by way of a pure person airplane interface M1. As M1 is a pure person airplane interface, no management airplane utility half is outlined for this interface. Two management airplane interfaces M2 and M3 are outlined. The appliance half on M2 interface conveys radio configuration knowledge for the multi-cell transmission mode eNBs. The appliance half on M3 interface between MBMS GW and MCE performs MBMS session management signaling on EPS bearer stage that features procedures corresponding to session begin and cease.

An essential requirement for multi-cell MBMS service transmission is MBMS content material synchronization to allow MBSFN operation. The eMBMS person airplane structure for content material synchronization is depicted in Determine 2.17. A SYNC protocol layer is outlined on the transport community layer (TNL) to assist the content material synchronization mechanism. The SYNC protocol carries extra data that allows eNBs to determine the timing for radio body transmission in addition to detect packet loss.

Determine 16: eMBMS logical structure.

Determine 17: The eMBMS person airplane structure for content material synchronization.

The eNBs taking part in multicell MBMS transmission are required to adjust to content material synchronization mechanism. An eNB transmitting solely in single-cell service isn’t required to adjust to the stringent timing necessities indicated by SYNC protocol. In case PDCP is used for header compression, it’s situated in eMBMS GW. The UEs receiving MTCH transmissions and collaborating in no less than one MBMS suggestions scheme have to be in an RRC CONNECTED state. Then again, UEs receiving MTCH transmissions with out collaborating in an MBMS suggestions mechanism might be in both an RRC IDLE or an RRC CONNECTED state. For receiving single-cell transmission of MTCH, a UE could have to be in RRC CONNECTED state. The signaling by which a UE is triggered to maneuver to RRC CONNECTED state solely for single-cell reception functions is carried on MCCH.

8. SUMMARY

The LTE system is predicated on extremely simplified community structure with solely two sorts of nodes specifically eNode-B and MME/GW. Essentially, it’s a flattened structure that allows simplified community design whereas nonetheless supporting seamless mobility and superior QoS mechanisms. It is a main change relative to conventional wi-fi networks with many extra community nodes utilizing hierarchical community structure. The simplification of community was

partly attainable as a result of LTE system doesn’t assist macro-range or smooth-handoff and therefore doesn’t require a RNC within the entry community for macro-range combining. Lots of the different RNC capabilities are integrated into the eNB. The QoS logical connections are offered between the UE and the gateway enabling differentiation of IP flows and assembly the necessities for low-latency functions.

A separate structure optimized for multi-cell multicast and broadcast is offered, which consists of two logical nodes specifically the multicast co-ordination entity (MCE) and the MBMS gateway. The MCE allocates radio sources in addition to determines the radio configuration for use by all eNBs within the MBSFN space. The MBMS gateway broadcasts MBMS packets with the SYNC protocol to every eNB transmitting the service. The MBMS gateway makes use of IP multicast for forwarding MBMS person knowledge to eNBs. The layer 2 and radio useful resource management protocols are designed to allow dependable supply of information, ciphering, header compression and UE energy financial savings.

9. REFERENCES

[1] 3GPPTS 36.300 V8.4.0, Advanced Common Terrestrial Radio Entry Network (E-UTRA): Total Description.

[2] 3GPP TS 29.060 V8.3.0, GPRS Tunneling Protocol (GTP) Throughout the Gn and Gp Interface.

[3] IETF RFC 4960, Stream Management Transmission Protocol.

[4] IETF RFC 3095, RObust Header Compression (ROHC): Framework and 4 Profiles: RTP, UDP, ESP, and uncompressed.

[5] 3GPP TS 36.331 V8.1.0, Radio Useful resource Management (RRC) Protocol Specification.

[6] 3GPP TR 23.882 V1.15.1, 3GPP System Architecture Evolution (SAE): Report on Technical Choices and Conclusions.