LTE介绍(诺基亚西门子内部培训资料).ppt

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1、LTE Overview,Sun ChangsongLBTS I&V HZ2009-05-05,Outline,LTE motivation and background 3GPP schedule LTE Key Technology LTE architecture LTE physical Layer LTE layer 2/3 LTE Peak Bit Rates Spectral Efficiency Voice evolution in LTE/SAE Nokia Siemens Networks LTE,LTE motivation and background,Wireline

2、 evolution pushes higher data rates,Wireless data usage requires more capacity,Flat rate pricing pushes efficiency,LTE expectations,Other technologies push wireless capabilities,Drivers for LTE,HSDPA data packages introduced traffic explodes,HSDPA data volume,ADSL,VDSL,GPON,40 Mbps,80 Mbps,10 MHz,20

3、 MHz,Elisa Flat rate 10-30/month,Several customers with 3 TB/day HSDPA traffic,3GPP schedule,LTE in 3GPP Release 8,3GPP and Operator RequirementsPacket Switched Domain OptimizedServer-UE RTT 30 msAccess Delay 300 msPeak Rates UL/DL 50/100 MbpsGood Mobility and SecurityImprove Terminal Power Efficien

4、cyFrequency Allocation Flexibility with 1.25/2.5,5,10,15 and 20 MHz AllocationsWCDMA evolution work to continue3-4 times higher capacity expected than with Release 6 HSDPA/HSUPA reference case,Study Phase2004:3GPP workshop on UTRAN Long Term Evolution03/2005 Start of the study12/2005 Multiple Access

5、 selected03/2006 eNB/Core functional split selected09/2006 close of the study item&approval of work planRelease 8 Stage 3 Output06/2008 baseline09/2008 baselineMajor PHY updates.12/2008 baselineMajor MAC updates.03/2009 baselineMajor L3 updates.ASN.1 for RRC.,LTE Key Technology,The Beauties of LTE,C

6、hannel only changes amplitude and phase of subcarriers,Advanced Scheduling Time&Freq.(Frequency Selective Scheduling),TX,RX,Tx,Rx,MIMOChannel,DL:OFDMAUL:SC-FDMA,scalable,HARQ:Hybrid Automatic Repeat Request,1,2,NACK,ACK,Rx Buffer,Combined decoding,LTE Architecture,Our Key Architectural ConceptFlat a

7、nd Cost effective Mobile Network,GSM/EDGE/UMTS/HSPA,Access,Core,Control,W-CDMA BTS,RNC,IMS,HLR/HSS,LTE/SAE,Shift of functionality,2GBTS,BSC,MSC,MGW,SGSN,GGSN,LTE BTS(eNodeB),MMESAE-GW,MGW,From CS to PS domain(VoIP),split of functions between eNodeB&aGW Interworking,smooth migration,service continuit

8、y and investment protection,LTE System Architecture,Control Plane,User Plane,Protocol Stacks,MAC,L2,eNB,S1,RLC,PHY,PHY,eUE,eUu,L1,aGW,L2,L1,IP,IP,UDP,UDP,GTP-U,GTP-U,PDCP,MAC,RLC,PDCP,L2,X2,L1,eNB,L2,L1,IP,IP,UDP,UDP,GTP-U,GTP-U,eNB,MAC,L2,eNB,S1,RLC,PHY,PHY,eUE,eUu,L1,MME,L2,L1,IP,IP,SCTP,SCTP,S1-A

9、P,S1-AP,PDCP,MAC,RLC,PDCP,RRC,RRC,NAS,NAS,L2,X2,L1,L2,L1,IP,IP,SCTP,SCTP,X2-AP,X2-AP,eNB,eNB,LTE Physical Layer,Functionality of Physical Layer,Data Transfer via Transport Channels.Error Detection.Hybrid ARQ Combining.Channel Coding and Rate Matching.Modulation and Demodulation.Measurements.MIMO,Tra

10、nsmit Diversity,Beamforming.RF Processing.,Orthogonal Frequency Division Multiplexing,25.892 Figure 1:Frequency-Time Representation of an OFDM Signal,OFDM is a digital multi-carrier modulation scheme,which uses a large number of closely-spaced orthogonal sub-carriers.Each sub-carrier is modulated wi

11、th a conventional modulation scheme(such as QPSK,16QAM,64QAM)at a low symbol rate similar to conventional single-carrier modulation schemes in the same bandwidth.,LTE Radio principles,Power efficient uplink increasing battery lifetime Improved cell edge performance by low peak to average ratio Reduc

12、ed Terminal complexity,Uplink:SC-FDMA,Enabling peak cell data rates of 173 Mbps DL and 58 Mbps in UL*Scalable bandwidth:1.4/3/5/10/15/20 MHz also allows deployment in lower frequency bands(rural coverage,refarming)Short latency:10 20 ms*,Improved spectral efficiency Reduced interference Very well su

13、ited for MIMO,Downlink:OFDMA,*At 20 MHz bandwidth,FDD,2 Tx,2 Rx,DL MIMO,PHY layer gross bit rate*roundtrip ping delay(server near RAN),downlink,OFMD Downlink&SC-FDMA Uplink-TDD Timing,SC-FDMA:PRBs are grouped to bring down Peak to Average Power Ratio(PAPR)better power efficiency at the terminal,1.4

14、MHz=72 Tones 20 MHz=1200 Tones,Subchannels/Tones(each 15 kHz),time,1 TTI=1ms,1 PRB(Physical Resource Block)=12 Subcarriers=180 kHz,1 PRB=2 Slots=2*0.5 ms,uplink,downlink,Special subframe containing guard period(switching from DL-UL),Physical Layer definitions TS36.211Frame Structure(DL)Slot/Frame,Ns

15、ymbDL OFDM symbols(=7 OFDM symbols Normal CP),Cyclic Prefix,160,2048,(x Ts),1slot=15360,1,0,2,3,4,5,6,1,0,2,3,4,5,6,0,1,2,3,4,5,6,1 frame,1 sub-frame,1 slot,#0,#1,#8,#2,#3,#4,#5,#6,#7,#9,#10,#11,#12,#19,#13,#14,#15,#16,#17,#18,Ts=1/(15000 x2048)=32.552nsec,Ts=1/(15000 x2048)=32.552nsec Ts:Time clock

16、 unit for definitions,Frame Structure type 2(TDD),DwPTS,T(variable),One radio frame,Tf=307200 x Ts=10 ms,One half-frame,153600 x Ts=5 ms,#0,#2,#3,#4,#5,One subframe,30720 x Ts=1 ms,Guard period,T(variable),UpPTS,(variable),One slot,Tslot=15360 x Ts=0.5 ms,#7,#8,#9,For 5ms switch-point periodicity,Fo

17、r 10ms switch-point periodicity,LTE Layer 2/3,User Plane LTE protocol stacks,PDCP,UE,RLC,MAC,Physical Layer,PDCP,eNode B,RLC,MAC,Physical Layer,LTE Layer 2,Layer 2 protocols(=MAC&RLC)terminate in BTS(eNode B)Also PDCP(Packet Data Convergence Protocol)terminates in eNode BPDCP includes IP header comp

18、ression and ciphering,Functionality of L2 Layer(MAC,RLC,PDCP),MAC Data Transfer via Logical Channels.Multiplexing Logical Channels and mapping to Transport Channels.Scheduling and Radio Resource Allocation between UEs and between Logical Channels.Transport Format Selection.Hybrid ARQ Protocol.,Funct

19、ionality of L2 Layer(MAC,RLC,PDCP),RLC TM,UM,AM Data Transfer.Automatic Repeat Request(ARQ)Protocol.Concatenation,Segmentation,Re-segmentation.In-Sequence Delivery.Duplicate Detection.,Functionality of L2 Layer(MAC,RLC,PDCP),PDCP Data Transfer for User and Control Plane.Header Compression.Ciphering.

20、Integrity Protection.Sequence Numbering.In-Sequence Delivery during HO.Duplicate Detection.,LTE Layer 3(RRC),Control Plane LTE protocol stacks,RRC,UE,RLC,MAC,Physical Layer,RRC,eNode B,RLC,MAC,Physical Layer,Radio Resource Control(RRC)signaling is also terminated in eNode B(compared to RNC in WCDMA)

21、One of the enablers for the flat model is the lack of macro-diversity RRC handles Broadcast,Paging,RRC connection management,Mobility managements and UE measurements,LTE Peak Bit Rates,Downlink Peak Bit Rate,2x2 MIMO 64QAM Pilot symbols 1 out of 14 Reference symbol overhead 7.7%Result:172 Mbps in 20

22、 MHz and 86 Mbps in 10 MHz,Uplink Peak Bit Rate,Single stream transmission 16QAM Pilot symbols 1 out of 14 57 Mbps in 20 MHz and 28 Mbps in 10 MHz,Spectral Efficiency,Frequency Reuse One in LTE,LTE is designed for frequency reuse of one no frequency planning required Inter-site interference coordina

23、tion is possible by exchanging load information over X2 interface=soft frequency reuse Current simulations show no clear performance gains in downlink from inter-site interference coordination Some performance potential in uplink by exchanging overload indicator information,X2,X2,Key Features for LT

24、E Downlink Spectral Efficiency Compared to HSPA R6,Inter-cell interference rejection combining or cancellation,MIMO=combined use of 2 tx and 2 rx antennas,Frequency domain packet scheduling,+10%,+20%,+40%,Total gain,up to 3.1x,OFDM with frequency domain equalization,+20.70%,Compared to single antenn

25、a BTS tx and 2-rx terminal,Not feasible in HSPA due to cdma modulation,Possible also in HSPA but better performance in OFDM solution,Due to orthogonality,3GPP R7 brings equalizer and MIMO also to HSPA,Voice evolution in LTE/SAE,Potential voice evolution steps in LTE,LTE used for high speed packet da

26、ta access onlyOperator voice service provided over CS networkFallback to CS voiceLTE network is used for data onlyTerminal is simultaneously registered to both LTE and 2G/3G CS networkVoice calls are initiated and received over CS networkSingle radio Voice Call Continuity(VCC)Operator provides VoIP

27、over LTEIMS acts as control machineryVoice calls can be handed over to CS networkAll-IP networkOperator provides VoIP over LTEIMS acts as control machineryVoice calls can be handed over to other packet switched networks,LTE voice evolution,Optionally:Complementary VoIP via IMS/NVS and PC-client,Opti

28、onally:Complementary VoIP via IMS/NVS,Nokia Siemens Networks LTE,Three sector site solution 1+1+1Multimode System Module3-sector RF Module 3 x 60 WMultimode HW available since Q3/2008 and SW-upgradeableto LTE!,Multimode System Module,3-sector RF Module,Complete Outdoor BTS(DC powered)Size:6U highVol

29、ume:50 litersWeight:50 kg,Flexi Multiradio BTS Site,Size Comparison,Flexi Multimode System Module Features,characteristics and capabilities,Flexi Multimode System ModuleOutdoor capable,low volume,low weightMature multimode HW for field deploymentIntegrated Baseband,BTS Control and Transport Optical

30、interfaces(OBSAI)to RF ModulesImportant part of Nokia Siemens Networks globally launched“Green Initiative”for environmental sustainability(Energy Efficiency solution),Outdoor capable-35+55 C,IP55 Volume:25 litersWeight:21 kg,Flexi Transport Modules,Flexi Multimode System ModulewithFlexi Transport(Su

31、b)Module,Multiple transport options,2 x GE electrical+1 x GE optical/electrical via SFP moduleGE optical/electrical via SFP module,FTHA,FTLB,3 x GE1)+4 x E1/T1/JT1 symm.(coaxial via patch panel)High-capacity(2Gbit/s IPSec)ToP,Sync Ethernet,16 x E1/T1/JT1 symmetrical(coaxial via patch panel),FTIB,FTJ

32、A,2 x FE,1 x GE 2)4 x E1 coaxial,2 x GE1)+4 x E1/T1/JT1 symm.(coaxial via patch panel)ToP(IEEE 1588v2),Sync Ethernet,3-Sector RF Module-Multiradio,Flexi 3-Sector RF Module with 3 x 70W power amplifiers delivers 3 x 60W at the antenna connector Improved OPEX,electricity consumption is 25%lower than p

33、revious generation RF 3 sectors LTE(1+1+1)with one RF Module20MHz bandwidthOutdoor IP65,-35+55 C Support for up to 20km distance from System Module(distributed site configuration)All 3GPP frequency bands to be supported according to market needs,Sector2 Tx&Rx,Sector 3 Tx&Rx,Sector3 Div Rx,Sector2 Di

34、v Rx,Sector1Div Rx,Ant6,Ant5,Ant4,Ant3,Ant2,Ant1,Sector1 Tx&Rx,The most cost and size optimized 3-sector RF configuration,Optional TMA/MHA,Optional AC/DC+Battery,Multimode System Module,Two 3-sector RF Modules,Flexi Multiradio BTS with MIMO(High Capacity Site),One System ModuleTwo 3-sector RF Module

35、s for 3 sectors3 cells/sectors 120W with 2x2 MIMO and 20MHz bandwidthRF Redundancy(implicitly)Optional 4 way UL diversityOptional TMA/MHAs,Q&A,Backup,Comparing OFDM and SC-FDMAQPSK example using N=4 subcarriers,The following graphs show how this sequence of QPSK symbols is represented in frequency and time,1,1,-1,-1,-1,1,1,-1,15 kHz,Frequency,fc,V,Time,CP,OFDMAData symbols occupy 15 kHz for one OFDMA symbol period,SC-FDMAData symbols occupy N*15 kHz for 1/N SC-FDMA symbol periods,60 kHz,Frequency,fc,V,Time,CP,