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  • 1. Technical Overview of 3GPP LTE May 18, 2008 Hyung G. Myung (hgmyung@ieee.org)
  • 2. Technical Overview of 3GPP LTE | Hyung G. Myung 1 Cellular Wireless System EvolutionCellular Wireless System EvolutionCellular Wireless System EvolutionCellular Wireless System Evolution • 1G (Early 1980s) – Analog speech communications. – Analog FDMA. – Ex: AMPS • 2G (Early 1990s) – Digital modulation of speech communications. – Advanced security and roaming. – TDMA and narrowband CDMA. – Ex: GSM, IS-95 (cdmaOne), and PDC • 3G (Late 1990s) – Global harmonization and roaming. – Wideband CDMA – Ex: UMTS, cdma2000, and TD-SCDMA Introduction
  • 3. Technical Overview of 3GPP LTE | Hyung G. Myung 2 Beyond 3GBeyond 3GBeyond 3GBeyond 3G • International Mobile Telecommunications (IMT)-2000 introduced global standard for 3G. • Systems beyond IMT-2000 (IMT-Advanced) is set to introduce evolutionary path beyond 3G. – Mobile class targets 100 Mbps with high mobility and nomadic/ local area class targets 1 Gbps with low mobility. • 3GPP and 3GPP2 are currently developing evolutionary/ revolutionary systems beyond 3G. – 3GPP Long Term Evolution (LTE) – 3GPP2 Ultra Mobile Broadband (UMB) • IEEE 802.16-based WiMAX is also evolving towards 4G through 802.16m. Introduction
  • 4. Technical Overview of 3GPP LTE | Hyung G. Myung 3 3GPP Evolution3GPP Evolution3GPP Evolution3GPP Evolution • Release 99 (Mar. 2000): UMTS/WCDMA • Rel-5 (Mar. 2002): HSDPA • Rel-6 (Mar. 2005): HSUPA • Rel-7 (2007): DL MIMO, IMS (IP Multimedia Subsystem), optimized real-time services (VoIP, gaming, push-to-talk). • Long Term Evolution (LTE) – 3GPP work on the Evolution of the 3G Mobile System started in November 2004. – Standardized in the form of Rel-8. – Spec finalized and approved in January 2008. – Target deployment in 2010. – LTE-Advanced study phase in progress. Introduction
  • 5. Technical Overview of 3GPP LTE | Hyung G. Myung 4 3GPP2 Evolution3GPP2 Evolution3GPP2 Evolution3GPP2 Evolution • CDMA2000 1X (1999) • CDMA2000 1xEV-DO (2000) • EV-DO Rev. A (2004): VoIP • EV-DO Rev. B (2006): Multi-carrier • Ultra Mobile Broadband (UMB), f.k.a. EV-DO Rev. C – Based on EV-DO, IEEE 802.20, and FLASH-OFDM – Spec finalized in April 2007. – Commercially available in early 2009. Introduction
  • 6. Technical Overview of 3GPP LTE | Hyung G. Myung 5 IEEE 802.16 EvolutionIEEE 802.16 EvolutionIEEE 802.16 EvolutionIEEE 802.16 Evolution • 802.16 (2002): Line-of-sight fixed operation in 10 to 66 GHz • 802.16a (2003): Air interface support for 2 to 11 GHz • 802.16d (2004): Minor improvements to fixes to 16a • 802.16e (2006): Support for vehicular mobility and asymmetrical link • 802.16m (in progress): Higher data rate, reduced latency, and efficient security mechanism Introduction
  • 7. Technical Overview of 3GPP LTE | Hyung G. Myung 6 Requirements of LTERequirements of LTERequirements of LTERequirements of LTE • Peak data rate – 100 Mbps DL/ 50 Mbps UL within 20 MHz bandwidth. • Up to 200 active users in a cell (5 MHz) • Less than 5 ms user-plane latency • Mobility – Optimized for 0 ~ 15 km/h. – 15 ~ 120 km/h supported with high performance. – Supported up to 350 km/h or even up to 500 km/h. • Enhanced multimedia broadcast multicast service (E-MBMS) • Spectrum flexibility: 1.25 ~ 20 MHz • Enhanced support for end-to-end QoS 3GPP LTE
  • 8. Technical Overview of 3GPP LTE | Hyung G. Myung 7 LTE Enabling TechnologiesLTE Enabling TechnologiesLTE Enabling TechnologiesLTE Enabling Technologies • OFDM (Orthogonal Frequency Division Multiplexing) • Frequency domain equalization • SC-FDMA (Single Carrier FDMA) • MIMO (Multi-Input Multi-Output) • Multicarrier channel-dependent resource scheduling • Fractional frequency reuse 3GPP LTE
  • 9. Technical Overview of 3GPP LTE | Hyung G. Myung 8 LTE Enabling TechnologiesLTE Enabling TechnologiesLTE Enabling TechnologiesLTE Enabling Technologies • Single Carrier FDMA (SC-FDMA) – SC-FDMA is a new single carrier multiple access technique which has similar structure and performance to OFDMA. • Utilizes single carrier modulation and orthogonal frequency multiplexing using DFT-spreading in the transmitter and frequency domain equalization in the receiver. – A salient advantage of SC-FDMA over OFDM/OFDMA is low PAPR. • Efficient transmitter and improved cell-edge performance. – H. G. Myung et al., “Single Carrier FDMA for Uplink Wireless Transmission,” IEEE Vehic. Tech. Mag., vol. 1, no. 3, Sep. 2006 – A comprehensive tutorial available at http://hgmyung.googlepages.com/scfdma.pdf. 3GPP LTE - cont.
  • 10. Technical Overview of 3GPP LTE | Hyung G. Myung 9 Key Features of LTEKey Features of LTEKey Features of LTEKey Features of LTE • Multiple access scheme – DL: OFDMA with CP. – UL: Single Carrier FDMA (SC-FDMA) with CP. • Adaptive modulation and coding – DL/UL modulations: QPSK, 16QAM, and 64QAM – Convolutional code and Rel-6 turbo code • Advanced MIMO spatial multiplexing techniques – (2 or 4)x(2 or 4) downlink and uplink supported. – Multi-user MIMO also supported. • Support for both FDD and TDD • H-ARQ, mobility support, rate control, security, and etc. 3GPP LTE
  • 11. Technical Overview of 3GPP LTE | Hyung G. Myung 10 LTE Standard SpecificationsLTE Standard SpecificationsLTE Standard SpecificationsLTE Standard Specifications • Freely downloadable from http://www.3gpp.org/ftp/Specs/html-info/36-series.htm Conformance testing.TS 36.5xx Infrastructure communications (UTRAN = UTRA Network) including base stations and mobile management entities. TS 36.4xx Layers 2 and 3: Medium access control, radio link control, and radio resource control. TS 36.3xx Physical layer.TS 36.2xx Equipment requirements: Terminals, base stations, and repeaters.TS 36.1xx Description of contents Specification index 3GPP LTE
  • 12. Technical Overview of 3GPP LTE | Hyung G. Myung 11 PHY: Physical layer MAC: Medium Access Control RLC: Radio Link Control Logical channels Transport channels Control/measurements Layer 3 Layer 2 Layer 1 RRC: Radio Resource Control Physical channels Transceiver Protocol ArchitectureProtocol ArchitectureProtocol ArchitectureProtocol Architecture 3GPP LTE
  • 13. Technical Overview of 3GPP LTE | Hyung G. Myung 12 LTE Network ArchitectureLTE Network ArchitectureLTE Network ArchitectureLTE Network Architecture • E-UTRAN (Evolved Universal Terrestrial Radio Access Network) NB: NodeB (base station) RNC: Radio Network Controller SGSN: Serving GPRS Support Node GGSN: Gateway GPRS Support Node RNC RNC SGSN GGSN NB NB NB NB UMTS 3G: UTRAN 3GPP LTE * 3GPP TS 36.300 eNB MME S-GW/P-GW MME S-GW/P-GW S1 X2 E-UTRAN EPC (Evolved Packet Core) eNB eNB eNB eNB: E-UTRAN NodeB MME: Mobility Management Entity S-GW: Serving Gateway P-GW: PDN (Packet Data Network) Gateway * 3GPP TS 36.300
  • 14. Technical Overview of 3GPP LTE | Hyung G. Myung 13 LTE Network ArchitectureLTE Network ArchitectureLTE Network ArchitectureLTE Network Architecture • eNB – All radio interface-related functions • MME – Manages mobility, UE identity, and security parameters. • S-GW – Node that terminates the interface towards E-UTRAN. • P-GW – Node that terminates the interface towards PDN. 3GPP LTE * 3GPP TS 36.300 eNB MME S-GW/P-GW MME S-GW/P-GW S1 X2 E-UTRAN EPC (Evolved Packet Core) eNB eNB eNB eNB: E-UTRAN NodeB MME: Mobility Management Entity S-GW: Serving Gateway P-GW: PDN (Packet Data Network) Gateway * 3GPP TS 36.300 - cont.
  • 15. Technical Overview of 3GPP LTE | Hyung G. Myung 14 LTE Network ArchitectureLTE Network ArchitectureLTE Network ArchitectureLTE Network Architecture * Non-roaming architecture * 3GPP TS 23.401 SGi S12 S3 S1-MME PCR S7 S6a HSS Operator's IP Services (e.g. IMS, PSS etc.) Rx+ S10 UE SGSN "LTE-Uu" E-UTRAN MME S11 S5Serving Gateway PDN Gateway S1-U S4 UTRAN GERAN 3GPP LTE - cont.
  • 16. Technical Overview of 3GPP LTE | Hyung G. Myung 15 LTE Network ArchitectureLTE Network ArchitectureLTE Network ArchitectureLTE Network Architecture * 3GPP TS 36.300 RRM: Radio Resource Management RB: Radio Bearer RRC: Radio Resource Control PDCP: Packet Data Convergence Protocol NAS: Non-Access Stratum EPS: Evolved Packet System 3GPP LTE - cont.
  • 17. Technical Overview of 3GPP LTE | Hyung G. Myung 16 LTE Network ArchitectureLTE Network ArchitectureLTE Network ArchitectureLTE Network Architecture User-Plane Protocol Stack Control-Plane Protocol Stack * 3GPP TS 36.300 3GPP LTE - cont.
  • 18. Technical Overview of 3GPP LTE | Hyung G. Myung 17 Frame StructureFrame StructureFrame StructureFrame Structure • Two radio frame structures defined. – Frame structure type 1 (FS1): FDD. – Frame structure type 2 (FS2): TDD. • A radio frame has duration of 10 ms. • A resource block (RB) spans 12 subcarriers over a slot duration of 0.5 ms. One subcarrier has bandwidth of 15 kHz, thus 180 kHz per RB. 3GPP LTE
  • 19. Technical Overview of 3GPP LTE | Hyung G. Myung 18 Frame Structure Type 1Frame Structure Type 1Frame Structure Type 1Frame Structure Type 1 • FDD frame structure One subframe = TTI (Transmission Time Interval) #0 #1 #2 #3 #18 #19 One slot = 0.5 ms One radio frame = 10 ms 3GPP LTE
  • 20. Technical Overview of 3GPP LTE | Hyung G. Myung 19 Frame Structure Type 2Frame Structure Type 2Frame Structure Type 2Frame Structure Type 2 • TDD frame structure 3GPP LTE Subframe #0 Subframe #2 Subframe #3 Subframe #4 Subframe #5 Subframe #7 Subframe #8 Subframe #9 DwPTS GP UpPTS DwPTS GP UpPTS One subframe = 1 ms One half-frame = 5 ms One radio frame = 10 ms One slot = 0.5 ms
  • 21. Technical Overview of 3GPP LTE | Hyung G. Myung 20 Resource GridResource GridResource GridResource Grid Slot #0 #19 One radio frame Subcarrier(frequency) OFDM/SC-FDMA symbol (time) RB RB scN N× 12 RB scN = symbN Resource block Resource element RB symb scN N= × resource elements 3GPP LTE
  • 22. Technical Overview of 3GPP LTE | Hyung G. Myung 21 Length of CPLength of CPLength of CPLength of CP symbN 6Extended CP 3Extended CP (∆f = 7.5 kHz)† 7Normal CP Configuration 512 (≈ 16.67 µs) for l = 0, 1, …, 5Extended CP 1024 (≈ 33.33 µs) for l = 0, 1, 2Extended CP (∆f = 7.5 kHz) † 160 (≈ 5.21 µs) for l = 0 144 (≈ 4.69 µs) for l = 1, 2, …, 6 Normal CP CP length NCP,l [samples]Configuration † Only in downlink 3GPP LTE
  • 23. Technical Overview of 3GPP LTE | Hyung G. Myung 22 LTE Bandwidth/Resource ConfigurationLTE Bandwidth/Resource ConfigurationLTE Bandwidth/Resource ConfigurationLTE Bandwidth/Resource Configuration 3GPP LTE 1536011520768038401920960Samples per slot 30.7223.0415.367.683.841.92Sample rate [MHz] 204815361024512256128 IDFT(Tx)/DFT(Rx) size 120090060030018072 Number of occupied subcarriers 100755025156 Number of resource blocks (NRB) 201510531.4 Channel bandwidth [MHz] *3GPP TS 36.104
  • 24. Technical Overview of 3GPP LTE | Hyung G. Myung 23 Bandwidth ConfigurationBandwidth ConfigurationBandwidth ConfigurationBandwidth Configuration frequency time 300 RB RB scN N× =12 RB scN = (7.68 MHz) 512 M = (4.5 MHz)(180 kHz) Resource block Zeros Zeros 1 slot DL or UL symbol * 5 MHz system with frame structure type 1 3GPP LTE
  • 25. Technical Overview of 3GPP LTE | Hyung G. Myung 24 LTE Physical ChannelsLTE Physical ChannelsLTE Physical ChannelsLTE Physical Channels • DL – Physical Broadcast Channel (PBCH) – Physical Control Format Indicator Channel (PCFICH) – Physical Downlink Control Channel (PDCCH) – Physical Hybrid ARQ Indicator Channel (PHICH) – Physical Downlink Shared Channel (PDSCH) – Physical Multicast Channel (PMCH) • UL – Physical Uplink Control Channel (PUCCH) – Physical Uplink Shared Channel (PUSCH) – Physical Random Access Channel (PRACH) 3GPP LTE
  • 26. Technical Overview of 3GPP LTE | Hyung G. Myung 25 LTE Transport ChannelsLTE Transport ChannelsLTE Transport ChannelsLTE Transport Channels • Physical layer transport channels offer information transfer to medium access control (MAC) and higher layers. • DL – Broadcast Channel (BCH) – Downlink Shared Channel (DL-SCH) – Paging Channel (PCH) – Multicast Channel (MCH) • UL – Uplink Shared Channel (UL-SCH) – Random Access Channel (RACH) 3GPP LTE
  • 27. Technical Overview of 3GPP LTE | Hyung G. Myung 26 LTE Logical ChannelsLTE Logical ChannelsLTE Logical ChannelsLTE Logical Channels • Logical channels are offered by the MAC layer. • Control Channels: Control-plane information – Broadcast Control Channel (BCCH) – Paging Control Channel (PCCH) – Common Control Channel (CCCH) – Multicast Control Channel (MCCH) – Dedicated Control Channel (DCCH) • Traffic Channels: User-plane information – Dedicated Traffic Channel (DTCH) – Multicast Traffic Channel (MTCH) 3GPP LTE
  • 28. Technical Overview of 3GPP LTE | Hyung G. Myung 27 Channel MappingsChannel MappingsChannel MappingsChannel Mappings PCCH BCCH CCCH DCCH DTCH MCCH MTCH Logical channels PMCH PDCCHPBCHPDSCH PCH DL-SCH MCH CCCH DCCH DTCH PUSCH PUCCHPRACH RACHBCH UL-SCH Transport channels Physical channels Downlink Uplink 3GPP LTE
  • 29. Technical Overview of 3GPP LTE | Hyung G. Myung 28 LTE Layer 2LTE Layer 2LTE Layer 2LTE Layer 2 • Layer 2 has three sublayers – MAC (Medium Access Control) – RLC (Radio Link Control) – PDCP (Packet Data Convergence Protocol) DL UL ROHC: Robust Header Compression * 3GPP TS 36.300 3GPP LTE
  • 30. Technical Overview of 3GPP LTE | Hyung G. Myung 29 RRC LayerRRC LayerRRC LayerRRC Layer • Terminated in eNB on the network side. • Functions – Broadcast – Paging – RRC connection management – RB (Radio Bearer) management – Mobility functions – UE measurement reporting and control • RRC states – RRC_IDLE – RRC_CONNECTED 3GPP LTE
  • 31. Technical Overview of 3GPP LTE | Hyung G. Myung 30 Resource Scheduling of Shared ChannelsResource Scheduling of Shared ChannelsResource Scheduling of Shared ChannelsResource Scheduling of Shared Channels • Dynamic resource scheduler resides in eNB on MAC layer. • Radio resource assignment based on radio condition, traffic volume, and QoS requirements. • Radio resource assignment consists of: – Physical Resource Block (PRB) – Modulation and Coding Scheme (MCS) 3GPP LTE
  • 32. Technical Overview of 3GPP LTE | Hyung G. Myung 31 Radio Resource ManagementRadio Resource ManagementRadio Resource ManagementRadio Resource Management • Radio bearer control (RBC) • Radio admission control (RAC) • Connection mobility control (CMC) • Dynamic resource allocation (DRA) or packet scheduling (PS) • Inter-cell interference coordination (ICIC) • Load balancing (LB) 3GPP LTE
  • 33. Technical Overview of 3GPP LTE | Hyung G. Myung 32 Other FeaturesOther FeaturesOther FeaturesOther Features • ARQ (RLC) and H-ARQ (MAC) • Mobility • Rate control • DRX (Discontinuous Reception) • MBMS • QoS • Security 3GPP LTE
  • 34. Technical Overview of 3GPP LTE | Hyung G. Myung 33 DL OverviewDL OverviewDL OverviewDL Overview • DL physical channels – Physical Broadcast Channel (PBCH) – Physical Control Format Indicator Channel (PCFICH) – Physical Downlink Control Channel (PDCCH) – Physical Hybrid ARQ Indicator Channel (PHICH) – Physical Downlink Shared Channel (PDSCH) – Physical Multicast Channel (PMCH) • DL physical signals – Reference signal (RS) – Synchronization signal • Available modulation for data channel – QPSK, 16-QAM, and 64-QAM 3GPP LTE
  • 35. Technical Overview of 3GPP LTE | Hyung G. Myung 34 DL Physical Channel ProcessingDL Physical Channel ProcessingDL Physical Channel ProcessingDL Physical Channel Processing Scrambling Modulation mapping Layer mapping OFDM signal generation Resource element mapping MIMO-related processing Precoding Mapping onto one or more transmission layers Generation of signals for each antenna port 3GPP LTE IDFT operation
  • 36. Technical Overview of 3GPP LTE | Hyung G. Myung 35 DL Reference SignalDL Reference SignalDL Reference SignalDL Reference Signal • Cell-specific 2D RS sequence is generated as the symbol-by- symbol product of a 2D orthogonal sequence (OS) and a 2D pseudo-random sequence (PRS). – 3 different 2D OS and ~170 different PRS. – Each cell (sector) ID corresponds to a unique combination of one OS and one PRS ⇒ ~510 unique cell IDs. • CDM of RS for cells (sectors)of the same eNodeB (BS) – Use complex orthogonal spreading codes. • FDM of RS for each antenna in case of MIMO 3GPP LTE
  • 37. Technical Overview of 3GPP LTE | Hyung G. Myung 36 DL Reference SignalDL Reference SignalDL Reference SignalDL Reference Signal *With normal CP *3GPP TS 36.211 0=l 0R 0R 0R 0R 6=l 0=l 0R 0R 0R 0R 6=l 0=l 0R 0R 0R 0R 6=l 0=l 0R 0R 0R 0R 6=l 0=l 1R 1R 1R 6=l 0=l 1R 1R 1R 1R 6=l 0=l 0R 0R 0R 0R 6=l 0=l 0R 0R 0R 0R 6=l 0=l 1R 1R 1R 1R 6=l 0=l 1R 1R 1R 1R 6=l 0=l 6=l 0=l 2R 6=l 0=l 6=l 0=l 6=l 2R 2R 2R 3R 3R 3R 3R 3GPP LTE - cont.
  • 38. Technical Overview of 3GPP LTE | Hyung G. Myung 37 DL MIMODL MIMODL MIMODL MIMO • Supported up to 4x4 configuration. • Support for both spatial multiplexing (SM) and Tx diversity (TxD) – SM • Unitary precoding based scheme with codebook based feedback from user. • Multiple codewords – TxD: SFBC/STBC, switched TxD, CDD (Cyclic Delay Diversity) considered. • MU-MIMO supported. 3GPP LTE
  • 39. Technical Overview of 3GPP LTE | Hyung G. Myung 38 UL OverviewUL OverviewUL OverviewUL Overview • UL physical channels – Physical Uplink Shared Channel (PUSCH) – Physical Uplink Control Channel (PUCCH) – Physical Random Access Channel (PRACH) • UL physical signals – Reference signal (RS) • Available modulation for data channel – QPSK, 16-QAM, and 64-QAM • Single user MIMO not supported in current release. – But it will be addressed in the future release. – Multi-user collaborative MIMO supported. 3GPP LTE
  • 40. Technical Overview of 3GPP LTE | Hyung G. Myung 39 UL Resource BlockUL Resource BlockUL Resource BlockUL Resource Block 1 slot (0.5 ms) Resource block (RB) Frequency Time One SC-FDMA symbol Subcarrier Reference symbols (RS) *PUSCH with normal CP 3GPP LTE
  • 41. Technical Overview of 3GPP LTE | Hyung G. Myung 40 UL Physical Channel ProcessingUL Physical Channel ProcessingUL Physical Channel ProcessingUL Physical Channel Processing Scrambling Modulation mapping Transform precoding SC-FDMA signal generation Resource element mapping SC-FDMA modulation DFT-precoding 3GPP LTE IDFT operation
  • 42. Technical Overview of 3GPP LTE | Hyung G. Myung 41 SCSCSCSC----FDMA Modulation in LTE ULFDMA Modulation in LTE ULFDMA Modulation in LTE ULFDMA Modulation in LTE UL Serial- to- Parallel M- IDFT N- DFT Zeros { }0 1 1, , Nx x x −… Parallel -to- Serial { }0 1 1, , Mx x x − ɶ ɶ ɶ… Subcarrier Mapping subcarrier 0M-1 Zeros One SC-FDMA symbol Localized mapping with an option of adaptive scheduling or random hopping. 3GPP LTE
  • 43. Technical Overview of 3GPP LTE | Hyung G. Myung 42 UL Reference SignalUL Reference SignalUL Reference SignalUL Reference Signal • Two types of UL RS – Demodulation (DM) RS ⇒ Narrowband. – Sounding RS: Used for UL resource scheduling ⇒ Broadband. • RS based on Zadoff-Chu CAZAC (Constant Amplitude Zero Auto-Correlation) polyphase sequence – CAZAC sequence: Constant amplitude, zero circular auto- correlation, flat frequency response, and low circular cross- correlation between two different sequences. 2 2 , 0,1,2, , 1; for even 2 ( 1) 2 , 0,1,2, , 1; for odd 2 k r k j qk k L L L r k k j qk k L L L e a e π π   − + = −     +  − + = −    =      ⋯ ⋯ * r is any integer relatively prime with L and q is any integer. B. M. Popovic, “Generalized Chirp-like Polyphase Sequences with Optimal Correlation Properties,” IEEE Trans. Info. Theory, vol. 38, Jul. 1992, pp. 1406-1409. 3GPP LTE
  • 44. Technical Overview of 3GPP LTE | Hyung G. Myung 43 UL RS MultiplexingUL RS MultiplexingUL RS MultiplexingUL RS Multiplexing subcarriers User 1 User 2 User 3 subcarriers FDM Pilots CDM Pilots 3GPP LTE
  • 45. Technical Overview of 3GPP LTE | Hyung G. Myung 44 UL RS MultiplexingUL RS MultiplexingUL RS MultiplexingUL RS Multiplexing • DM RS – For SIMO: FDM between different users. – For SU-MIMO: CDM between RS from each antenna – For MU-MIMO: CDM between RS from each antenna • Sounding RS – CDM when there is only one sounding bandwidth. – CDM/FDM when there are multiple sounding bandwidths. 3GPP LTE - cont.
  • 46. Technical Overview of 3GPP LTE | Hyung G. Myung 45 Cell SearchCell SearchCell SearchCell Search • Cell search: Mobile terminal or user equipment (UE) acquires time and frequency synchronization with a cell and detects the cell ID of that cell. – Based on BCH (Broadcast Channel) signal and hierarchical SCH (Synchronization Channel) signals. • P-SCH (Primary-SCH) and S-SCH (Secondary-SCH) are transmitted twice per radio frame (10 ms) for FDD. • Cell search procedure 1. 5 ms timing identified using P-SCH. 2. Radio timing and group ID found from S-SCH. 3. Full cell ID found from DL RS. 4. Decode BCH. 3GPP LTE
  • 47. Technical Overview of 3GPP LTE | Hyung G. Myung 46 Random AccessRandom AccessRandom AccessRandom Access • Non-synchronized random access. • Open loop power controlled with power ramping similar to WCDMA. • RACH signal bandwidth: 1.08 MHz (6 RBs) • Preamble based on CAZAC sequence. CP Preamble TCP TGP RA slot = 1 ms * TCP = 0.1 ms, TGP = 0.1 ms *3GPP TR 25.814 3GPP LTE
  • 48. Technical Overview of 3GPP LTE | Hyung G. Myung 47 Other ProceduresOther ProceduresOther ProceduresOther Procedures • Synchronization procedures – Radio link monitoring – Inter-Cell synchronization for MBMS – Transmission timing adjustments • Power control for DL and UL • UE procedure for CQI (Channel Quality Indication) reporting • UE procedure for MIMO feedback reporting • UE sounding procedure 3GPP LTE
  • 49. Technical Overview of 3GPP LTE | Hyung G. Myung 48 SummarySummarySummarySummary • Key technologies of LTE system – Multicarrier-based radio air interface • OFDMA and SC-FDMA – IP-based flat network architecture – Multi-input multi-output (MIMO) – Active interference avoidance and coordination • Fractional frequency re-use (FFR) – Fast frequency-selective resource scheduling Summary and References
  • 50. Technical Overview of 3GPP LTE | Hyung G. Myung 49 SummarySummarySummarySummary Multi-layer precoded spatial multiplexing, space-time transmit diversity, spatial division multiple access, and beamforming. Convolutional coding, turbo coding, and LDPC coding 512 9.6 kHz QPSK, 8PSK, 16QAM, and 64QAM Yes Localized and distributed FDD and TDD OFDMA and CDMA OFDMA 1.25, 2.5, 5, 10, and 20 MHz 3GPP2 UMB Beamforming, Space-time coding, and spatial multiplexing Convolutional coding and convolutional turbo coding. Block turbo coding and LDPC coding optional. 512 10.94 kHz QPSK, 16QAM, and 64QAM Yes Localized and distributed TDD OFDMA OFDMA 5, 7, 8.75, and 10 MHz Mobile WiMAX Multi-layer precoded spatial multiplexing space-time/frequency block coding, switched transmit diversity, and cyclic delay diversity MIMO Convolutional coding and turbo coding. Channel coding 512FFT size (5 MHz) 15 kHzSubcarrier spacing QPSK, 16QAM, and 64QAMData modulation YesSubcarrier hopping LocalizedSubcarrier mapping FDD and TDDDuplexing SC-FDMAUL multiple access OFDMADL multiple access 1.4, 3, 5, 10, 15, and 20 MHzChannel bandwidth 3GPP LTE Summary and References - cont.
  • 51. Technical Overview of 3GPP LTE | Hyung G. Myung 50 References and ResourcesReferences and ResourcesReferences and ResourcesReferences and Resources • LTE enabling technologies – OFDM/OFDMA • R. van Nee and R. Prasad, OFDM for Wireless Multimedia Communications, Artech House, 2000. – SC-FDMA • H. G. Myung et al., “Single Carrier FDMA for Uplink Wireless Transmission,” IEEE Vehicular Technology Mag., vol. 1, no. 3, Sep. 2006. • http://hgmyung.googlepages.com/scfdma – MIMO • A. Paulraj et al., Introduction to Space-Time Wireless Communications, Cambridge University Press, May 2003. • G. L. Stüber et al., “Broadband MIMO-OFDM Wireless Communications,” Proceedings of the IEEE, Feb. 2004, vol. 92, no. 2, pp. 271-294. – Multicarrier scheduling • G. Song and Y. Li, “Utility-based Resource Allocation and Scheduling in OFDM-based Wireless Broadband Networks,” IEEE Commun. Mag., vol. 43, no. 12, Dec. 2005, pp. 127-134. Summary and References
  • 52. Technical Overview of 3GPP LTE | Hyung G. Myung 51 References and ResourcesReferences and ResourcesReferences and ResourcesReferences and Resources • 3GPP LTE – Spec • http://www.3gpp.org/ftp/Specs/html-info/36-series.htm • http://www.3gpp.org/ftp/Specs/html-info/25814.htm (old) – E. Dahlman et al., 3G Evolution: HSPA and LTE for Mobile Broadband, Academic Press, 2007 – H. Ekström et al., “Technical Solutions for the 3G Long-Term Evolution,” IEEE Commun. Mag., vol. 44, no. 3, March 2006, pp. 38-45 – 3G Americas, “Mobile Broadband: The Global Evolution of UMTS/HSPA - 3GPP Release 7 and Beyond" available at http://www.3gamericas.org/pdfs/UMTS_Rel7_Beyond_Dec2006.p df – http://www.LTEwatch.com Summary and References - cont.
  • 53. Thank you! May 18, 2008 Hyung G. Myung (hgmyung@ieee.org)