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IPEEC 2007년 2차 강의 (특허 심사관 IT 신기술 교육센터) IT R&D Global Leader 통신단말/무선전송 IPEEC 2007년 2차 강의 (특허 심사관 IT 신기술 교육센터) IT R&D Global Leader 통신단말/무선전송 파트 강좌: Mobile Research Activites of ETRI 3 G LTE 기술 2007. 03. 08 이동통신연구단 무선전송기술연구그룹 김영훈 Confidential - -

Contents Ⅰ Part I: 3 G LTE Background Ⅱ Part II: 3 G LTE Contents Ⅰ Part I: 3 G LTE Background Ⅱ Part II: 3 G LTE 표준 및 동향 Ⅲ Part III: 3 G LTE 요소 기술 소개 Confidential -2 -

Part I: 3 G LTE Background Confidential -3 - Part I: 3 G LTE Background Confidential -3 -

이동통신 종류 q 아날로그 셀룰러 (Analog Cellular) 시스템 v 1983년 아날로그 셀룰러 시스템 서비스 이동통신 종류 q 아날로그 셀룰러 (Analog Cellular) 시스템 v 1983년 아날로그 셀룰러 시스템 서비스 시작 (AMPS: Advanced Mobile Phone Service) q 디지탈 셀룰러 (Digital Cellular) 시스템 v 1990년 CDMA 방식 표준화 결정 (IS-95) v IMT-2000 (International Mobile Telecommunications – 2000) : 2 GHz 대역 ü EV-DO/DV, HSDPA/HSUPA q Wi. Fi, Wi. Max, Wibro q 3 G LTE (Long Term Evolution) v 3 GPP/3 GPP 2 q 4세대 이동통신 시스템 (? ) Confidential -4 -

이동통신 서비스 진화(1/2) Partition ~2001 2002 2003 2004 2005~2011 2012~ DMB Broadcasting 3 G 이동통신 서비스 진화(1/2) Partition ~2001 2002 2003 2004 2005~2011 2012~ DMB Broadcasting 3 G LTE DVB/ DAB 3. 5 G Cellular 2 G Advanced DSRC 802. 11 p cdma 2000/W-CDMA FWA/BWA DSRC 802. 16/16 a/16 d WLL Broadband Wireless Access 2. 4 GHz WLAN Wi. Bro II Ubiquitous Convergence Service Mobile BWA/ Wi. Bro I cdma. One/GSM ITS 4 G Nomadic/ Local Wireless Access EV-DV/HSDPA 3 G 4 G New Mobile Access 5 GHz WLAN 802. 11 b/g WLAN Confidential 802. 16 e High-speed WLAN 802. 11 a 802. 11 n High-speed Wireless Indoor Sensor Network WPAN / RFID -5 -

이동통신 서비스 진화(2/2) High-tier Systems beyond IMT-2000 will encompass the capabilities of previous systems 이동통신 서비스 진화(2/2) High-tier Systems beyond IMT-2000 will encompass the capabilities of previous systems Low-tier System Peak data rate (Mbps) q 3 G evolution의 위치 v 3 G evolution은 IMT-2000의 진화형태이고, 4 G new mobile access가는 중간단계 v Wi. Bro와 다른 점은 보다 높은 이동속도와 넓은 커버리지를 지원. v 3 G evolution은 초기 Hot spot cell로 출발하여 점점 광역화할 것으로 예상 v 당분간은 3 GPP계열쪽은 W-CDMA+3 GE(혹은 HSDPA)+WLAN 결합으로 유비쿼터스 서비스 실현 Confidential -6 -

이동통신 표준화 기구(1/4) q ITU (International Telecommunication Union) v 국제 통신 연합 v 1865년 이동통신 표준화 기구(1/4) q ITU (International Telecommunication Union) v 국제 통신 연합 v 1865년 설립 (1947년 국제연합 (UN) 전문기구) v 1998년 3 G 이동통신 표준화 작업 허가 (ITU-T: Telecommunication Standardization Sector) ü ITU-DS: UMTS frequency division duplex (FDD) ü ITU-MC: CDMA-2000 ü ITU-TC: UMTS time division duplex (TDD), time division synchronous CDMA ü ITU-SC: UWC-136 (EDGE standard) ü ITU-FT: DECT (Digital Enhanced Cordless Telecommunications) Confidential -7 -

이동통신 표준화 기구(2/4) q 3 GPP (3 rd Generation Partnership Project) v European Telecommunications 이동통신 표준화 기구(2/4) q 3 GPP (3 rd Generation Partnership Project) v European Telecommunications Standards Institute (ETSI) 주도 v Global System for Mobile (GSM)을 기반으로 한 3세대 이동통신 표준화 (FDD/TDD) v Technical Specification Groups ü TSG GERAN (GSM EDGE RAN) RAN (Radio Access Network) SA (Services & System Aspects) CT Core Network & Terminals v General Packet Radio Service (GPRS), Enhanced Data rates for GSM Evolution (EDGE) 표준화 포함 Confidential -8 -

이동통신 표준화 기구(3/4) q 3 GPP 2 (3 rd Generation Partnership Project 2) v 이동통신 표준화 기구(3/4) q 3 GPP 2 (3 rd Generation Partnership Project 2) v 북아메리카 (미국), 아시아 (한국, 일본) 참여 v IS-95 a/IS-95 b 기반 v cdma 2000 (1 x. EV-DO/DV) v ANSI/TIA/EIA-41 표준화 v Technical Specification Groups ü TSG-A: Access Network Interfaces ü TSG-C: cdma 2000 ü TSG-S: Service and System Aspects ü TSG-X: Core Networks Confidential -9 -

이동통신 표준화 기구(4/4) q IEEE 802 v IEEE 802 LAN/MAN Standards Committee ü Local 이동통신 표준화 기구(4/4) q IEEE 802 v IEEE 802 LAN/MAN Standards Committee ü Local Area Network standards and Metropolitan Area Network ü Ethernet, Token Ring, Wireless LAN, Bridging and Virtual Bridged LANs v Working Group ü 802. 11 Wireless LAN Working Group : Wi. Fi ü 802. 15 Wireless Personal Area Network (WPAN) Working Group – 15. 1 Bluetooth ü 802. 16 Broadband Wireless Access Working Group – 16 Wireless. MAN (10 to 66 GHz) : Wi. Max – 16 e (2 – 6 GHz) : Wi. Bro ü 802. 20 Mobile Broadband Wireless Access (MBWA) Working Group ü 802. 21 Media Independent Handoff Working Group q 용어 (참고) v v 기지국/AS/Node. B/BS/Base Station/BTS 단말기/단말국/Terminal/UE/Mobile Station/Handset Downlink/Forward link/하향링크 Uplink/Reverse link/상향링크 Confidential - 10 -

Wireless Channels q Channel impairments v Multipath channel(Delay spread) Frequency selectivity f v Mobility(Doppler Wireless Channels q Channel impairments v Multipath channel(Delay spread) Frequency selectivity f v Mobility(Doppler spread) Time selectivity t Diversity Techniques (Frequency, Time, Spatial) Confidential - 11 -

OFDM Basics(1/4) q Demands: High Data Rate Wireless Communications v Future services : > OFDM Basics(1/4) q Demands: High Data Rate Wireless Communications v Future services : > 10 ~ 1000 Mbps v Broadband spectrum: > 5 MHz v Delay spread & doppler spread of wireless channels ü Inter-symbol interference (ISI) ü High complexity with single carrier receivers : Equalizer or Rake receiver q Multi-Carrier Modulation (MCM) v Wideband Multiple narrowband subchannels ü Transmission of signals with longer data duration in parallel ü Robust to ISI v Each subchannel goes through flat fading OFDM based MA schemes f Confidential - 12 -

OFDM Basics(2/4) q Orthogonal Frequency Division Multiplexing (OFDM) v Advantages ü A kind of OFDM Basics(2/4) q Orthogonal Frequency Division Multiplexing (OFDM) v Advantages ü A kind of MCM : robust to multipath fading proper scheme for WB ü High bandwidth efficiency – Subchannel spectra are orthogonally overlapped ü Low complexity – Implemented with FFT techniques (Flat fading channel assumption) ü ISI immunity – Cyclic prefix can eliminate the ISI ü Capacity enhancement with advanced techniques – Adapting the data rate per subchannel – Multiple input multiple out (MIMO) technologies ü Insensitive to timing error in certain condition v Disadvantages ü High peak to average power ratio high power consumption & nonlinear effect ü Interchannel interference (ICI) due to Doppler spread ü Sensitive to frequency offset and phase noise Confidential - 13 -

OFDM Basics(3/4) q OFDM Signal Representation in RF signal v fc : center frequency OFDM Basics(3/4) q OFDM Signal Representation in RF signal v fc : center frequency v T : symbol duration v N : # of subcarriers in OFDM f Confidential - 14 -

OFDM Basics(4/4) Basic OFDM Tranceivers Confidential - 15 - OFDM Basics(4/4) Basic OFDM Tranceivers Confidential - 15 -

OFDM 기반 Multiple Access Schemes q Multiple Access 분류 v 주파수, 시간, 코드: OFDMA, OFDM 기반 Multiple Access Schemes q Multiple Access 분류 v 주파수, 시간, 코드: OFDMA, OFDM-TDMA, OFDM-CDMA(MCCDMA, MC-DSCDMA) Confidential - 16 -

PAPR in OFDM (1/2) q Definition of Peak-to-Average Power Ratio (PAPR) v The ratio PAPR in OFDM (1/2) q Definition of Peak-to-Average Power Ratio (PAPR) v The ratio of the instantaneous peak value, i. e. , maximum magnitude, of a signal parameter to its time-averaged value. v Measure of the envelope variation Confidential - 17 -

PAPR in OFDM (2/2) q High PAPR Problem v Requires a large dynamic range PAPR in OFDM (2/2) q High PAPR Problem v Requires a large dynamic range of DAC and ADC inefficient, quantization noise v Requires inefficient (large) power back-off v Large precision is required, meaning a large number of bits (cost) v Severe power efficiency penalty and expensive q Existing PAR Reduction Techniques v Block Coding Method v Clipping effect transformation v DFT-spreading Confidential - 18 -

SC-FDMA Basics q Basics about SC-FDMA v Originated from Interleaved FDMA (IFDMA) by German SC-FDMA Basics q Basics about SC-FDMA v Originated from Interleaved FDMA (IFDMA) by German Aerospace Center (DLR), Dr Schnell(Dr. Uli Sorger)이 1998년에 제안 v A kind of multi carrier spread spectrum scheme, User discrimination is doing using FDMA v Two types: ü Localized FDMA (LFDMA) ü Distributed FDMA (DFDMA) = IFDMA q Advantages v User간의 othogonality 보장: no MAI v Low PAPR: UE의 전력소모 감소 q Disadvantages v ISI 존재: equalizer 필요 Frequency Domain Equalization Confidential - 19 -

SC-FDMA Basics IFDMA Confidential - 20 - SC-FDMA Basics IFDMA Confidential - 20 -

SC-FDMA Basics Time domain TX 구현 Frequency domain TX 구현 Confidential - 21 - SC-FDMA Basics Time domain TX 구현 Frequency domain TX 구현 Confidential - 21 -

Frequency Domain Equalization q 광대역 multi-path 채널일 경우 기존의 time-domain 등 화기는 복잡도가 높음 Frequency Domain Equalization q 광대역 multi-path 채널일 경우 기존의 time-domain 등 화기는 복잡도가 높음 주파수 도메인 등화기 필요 D. Falconer, S. L. Ariyavisitakul, et. Al. , “Frequency Domain Equalization for Single-Carrier Broadband Wireless System, ” IEEE Comm. Mag. , vol 40, no. 4, April 2002, pp. 58 -66. Confidential - 22 -

Single Carrier Modulation with FDE(1/2) Confidential - 23 - Single Carrier Modulation with FDE(1/2) Confidential - 23 -

Single Carrier Modulation with FDE(2/2) q SC/FDE 는 비슷한 성능 및 복잡도를 갖는다. q Single Carrier Modulation with FDE(2/2) q SC/FDE 는 비슷한 성능 및 복잡도를 갖는다. q OFDM에 대한 SC/FDE 장점 v TX에서의 Single Carrier modulation에 의한 낮은 PAPR v Spectral Null에 강하다. v Carrier Frequency Offset에 민감하지 않다. v 낮은 TX 복잡도로 인해 상향링크에 적절하다. q Single carrier FDMA(SC-FDMA)는 multiple user access 의 SC/FDE 확장 Confidential - 24 -

SC-FDMA Confidential - 25 - SC-FDMA Confidential - 25 -

SC-FDMA vs OFDMA q Similarities v Block-based modulation v Divides the transmission bandwidth into SC-FDMA vs OFDMA q Similarities v Block-based modulation v Divides the transmission bandwidth into smaller subcarriers v Channel equalization is done in the freqnecy domain v CP is added to overcome IBI and to convert linear convolution of the channel impulse response to circular one v SC-FDMA can be regarded as DFT-precoded or DFT-spread OFDMA q Dissimilarities v Channel Equalization ü OFDMA: Sub-carrier당 detection, spectrum null이 생길경우 성능 열화, 채널 코딩등 이 필요 ü SC-FDMA: IDFT이후 detection, 일정 bandwidth를 통해 SNR이 average 됨. Confidential - 26 -

SC-FDMA vs OFDMA q Dissimilarities v Time domain symbol duration ü OFDMA: 변조된 심볼 SC-FDMA vs OFDMA q Dissimilarities v Time domain symbol duration ü OFDMA: 변조된 심볼 구간이 입력 데이터 심볼 구간보다 길음 ü SC-FDMA: 변조된 심볼 구간이 입력 데이터 심볼 구간보다 짧음 v PAPR ü OFDMA: High PAPR ü SC-FDMA: Low PAPR Confidential - 27 -

Synchronization and Cell Search(1/2) q Frame/Symbol Synchronization v Find the frame start and OFDM Synchronization and Cell Search(1/2) q Frame/Symbol Synchronization v Find the frame start and OFDM symbol (FFT start position) v To minimize the effects of ICI and ISI v Should be carried out prior to any demodulation processing in RX v Timing error within Cyclic Prefix region can be compensated with equalizer v Need efficient and low-cost HW Confidential - 28 -

Synchronization and Cell Search(2/2) q Cell Search: v 단말이 현재 어느 셀에 위치에 있는지 Synchronization and Cell Search(2/2) q Cell Search: v 단말이 현재 어느 셀에 위치에 있는지 찾는 기능(Finding Cell ID) v 동기채널에 Cell 구분을 할 수 있는 정보를 보냄 Confidential - 29 -

Frequency offset and Timing offset q Frequency Offset and Doppler frequency v Frequency Offset은 Frequency offset and Timing offset q Frequency Offset and Doppler frequency v Frequency Offset은 기지국과 단말기의 오실레이터에 의한 RF frequency 차이로 부터 발생. 단말기가 이 차이를 보상해야 함. 보 상하기 상대적으로 쉬움 v Doppler frequency는 단말기의 이동속도에 따라 발생. 시간에 따 라 주파수 차이가 변함. v 영향: OFDM에서는 상당히 민감하게 성능에 영향을 줌. q Timing Offset v 주로 Frame/Symbol timing estimation error에 의해 발생 v 영향: OFDM에서는 상대적으로 덜 민감. Confidential - 30 -

Effect of Carrier Frequency Offset q Effect of Frequency Offset on QPSK Constellation Confidential Effect of Carrier Frequency Offset q Effect of Frequency Offset on QPSK Constellation Confidential - 31 -

Effect of Timing Errors (1/2) q Case of Timing Errors v Case A : Effect of Timing Errors (1/2) q Case of Timing Errors v Case A : No timing error v Case B : Timing error within the guard interval v Case C : Timing error out of the guard interval Confidential - 32 -

Effect of Timing Errors (2/2) q Effect of Timing Errors Case C Case B Effect of Timing Errors (2/2) q Effect of Timing Errors Case C Case B Confidential - 33 -

Frequency offset compensation q Frequency Offset Estimation and Compensation v Need good estimation: estimation Frequency offset compensation q Frequency Offset Estimation and Compensation v Need good estimation: estimation error less than 1 % of carrier spacing v Time Domain method: ü ü Using preamble that consists of repeated short codes in time domain relatively efficient and cheap (fractional and integer frequency offset) suitable for coarse estimation sensitive to channel impairments v Frequency Domain methods: ü Using the same pilot tones or preamble in frequency domain (fractional or integer frequency offset) ü suitable for fine estimation ü relatively insensitive to channel impairments Confidential - 34 -

Channel Estimation and Equalization q Channel estimation and Equalization (1/3) v Frequency selective fading Channel Estimation and Equalization q Channel estimation and Equalization (1/3) v Frequency selective fading channel vs. Flat fading channel ü Wideband Frequency selective fading channel severe ISI ü OFDM : Wideband Narrowband (Frequency selective fading channel Flat fading channel) Confidential - 35 -

Channel Estimation and Equalization q Channel estimation and Equalization (2/3) v Pilot sub-carrier arrangement Channel Estimation and Equalization q Channel estimation and Equalization (2/3) v Pilot sub-carrier arrangement depends on SYSTEM! various estimation schemes Slow Fading Block-type Channel Pilot arrangement Fast Fading Comb-type Channel Pilot arrangement Comb-type Pilot arrangement Confidential - 36 -

Channel Estimation and Equalization q Channel estimation and Equalization (3/3) v Channel estimation algorithm Channel Estimation and Equalization q Channel estimation and Equalization (3/3) v Channel estimation algorithm ü MMSE vs. LS type: LS is cheap!! Performance degradation under AWGN at low SNR v Channel estimation at data tone location ü Decision Directed method: Block-type ü Interpolation between pilot tone locations – Linear, high-order polynomial, Winner optimal filter (expensive!) – Linear works fine v Equalization ü 1 -tap equalizer per a sub-carrier: HW uses a single engine (time sharing) ü Simple zero-forcing type equalizer v Considerations ü Coherence Time: Doppler effect (maximum mobile speed) slow or fast fading ü Coherence Bandwidth: channel Interpolation Confidential - 37 -

Channel Estimation and Equalization Confidential - 38 - Channel Estimation and Equalization Confidential - 38 -

Timing Control in OFDM based system q Intra-cell interference due to different propagation delay Timing Control in OFDM based system q Intra-cell interference due to different propagation delay v Uplink synchronization needed Base Station Confidential - 39 -

MIMO Spatial Processing q BLAST (Bell Labs Space Time) v Multiple antenna technique for MIMO Spatial Processing q BLAST (Bell Labs Space Time) v Multiple antenna technique for higher data rate v Independent data streams on each antenna v MUD RX algorithms v Rich scattering channels Confidential - 40 -

Handover(1/4) Cell A Cell B In the soft handoff process, the communication link with Handover(1/4) Cell A Cell B In the soft handoff process, the communication link with the mobile station is maintained at all times. - 41 -

Handover(2/4) Sector B Sector A Sector C In the softer handoff process, the mobile Handover(2/4) Sector B Sector A Sector C In the softer handoff process, the mobile station selects the strongest signal from different sectors. - 42 -

Handover(3/4) Cell A Cell B In the hard handoff process, the communication link with Handover(3/4) Cell A Cell B In the hard handoff process, the communication link with the mobile station is momentarily disrupted. - 43 -

Handover(4/4) q. Signal levels during handover Confidential - 44 - Handover(4/4) q. Signal levels during handover Confidential - 44 -

Power Control(1/2) q To ensure each UE receives & transmits enough energy to convey Power Control(1/2) q To ensure each UE receives & transmits enough energy to convey information properly while interfering w. other users no more than necessary. Confidential - 45 -

Power Control(2/2) q Open-Loop Power Control v in UL only v to set Initial Power Control(2/2) q Open-Loop Power Control v in UL only v to set Initial Power of UE q Closed-Loop Power Control v in UL & DL v typically up/down 1 d. B over 70 d. B range (-50 d. Bm ~ 21 d. Bm) Confidential - 46 -

Mapping between Transport & Physical CHs Node. B DCH UE DPDCH, DPCCH Node. B Mapping between Transport & Physical CHs Node. B DCH UE DPDCH, DPCCH Node. B DCH HS-DSCH UE HS-PDSCH HS-SCCH PRACH AICH RACH PCPCH AP-AICH CPCH HS-DPCCH E-DPDCH E-DCH EDPCCH E-AGCH, E-RGCH CD/CA-ICH CSICH E-HICH DSCH BCH FACH, PCH PDSCH CPICH P-CCPCH S-CCPCH PICH MICH General coding/Multiplexing of Tr. CH s Confidential - -

Transmit Diversity q Why transmit diversity? v Increases capacity in down-link with insufficient small Transmit Diversity q Why transmit diversity? v Increases capacity in down-link with insufficient small delay spread and small Doppler spread (limited space diversity of Rake and time diversity of interleaving) q What kinds of transmit diversity? v Open loop methods ü Time switched transmit diversity (TSTD) ü Space time block coding transmit diversity (STTD) v Closed loop method ü Transmit adaptive array (Tx. AA) Confidential - -

HSDPA/HSUPA(1/4) Confidential - 49 - HSDPA/HSUPA(1/4) Confidential - 49 -

HSDPA/HSUPA(2/4) Included in HSDPA AMC Enhanced in HSDPA Excluded from HSDPA Multi-code operation SHO HSDPA/HSUPA(2/4) Included in HSDPA AMC Enhanced in HSDPA Excluded from HSDPA Multi-code operation SHO H-ARQ Basic WCDMA Technology PC TTI = 2 ms Variable SF Advanced PS Confidential - 50 -

HSDPA/HSUPA(3/4) q AMC (Adaptive Modulation and Coding) v R’ 99: Fast PC, dynamic range: HSDPA/HSUPA(3/4) q AMC (Adaptive Modulation and Coding) v R’ 99: Fast PC, dynamic range: 20 d. B in the DL, 70 d. B in the UL v HSDPA: Link adoption function and AMC v QPSK/16 QAM, Coding Rate(1/4 ~ 4/4) according to channel status v Measurement of channel status at UE, report to Node B -> CQI (Channel Quality Indicator) q HARQ (Hybrid Automatic Repeat Request) v Retransmission when Packet Error occurs v Utilization of error Packet and retransmitted Packet in order to restore the data v R’ 99: RNC-based ARQ v HSDPA: Physical layer fast H-ARQ v Additional intelligence (HSDPA MAC – MAC hs) is installed at the Node. B. v Retransmission controlled by the Node. B leads to faster execution and shorter delay in case of retransmissions. v The Iub interface (Node. B-RNC) requires a flow control mechanism to Confidential ensure that Node. B buffers are used properly and there is no buffer - 51 -

HSDPA/HSUPA(4/4) v RNC still retains the RLC functionalities (providing retransmission in cases when HS-DSCH HSDPA/HSUPA(4/4) v RNC still retains the RLC functionalities (providing retransmission in cases when HS-DSCH Node. B retransmission fails). v New MAC functionality at the Node. B (MAC-hs) handles the ARQ, scheduling, and priority handling. Confidential - 52 -

HSDPA/HSUPA Confidential - 53 - HSDPA/HSUPA Confidential - 53 -

Part II: 3 G LTE 표준 및 동향 Confidential - 54 - Part II: 3 G LTE 표준 및 동향 Confidential - 54 -

3 GPP Milestone Confidential - 55 - 3 GPP Milestone Confidential - 55 -

3 GPP 표준 기구 조직 및 활동 Confidential - 56 - 3 GPP 표준 기구 조직 및 활동 Confidential - 56 -

3 GPP TSG RAN q TSG RAN Objectives v Define and further develop the 3 GPP TSG RAN q TSG RAN Objectives v Define and further develop the UMTS (WCDMA and TDD including TD SCDMA) Radio Access Network v Specify tests for User Equipment as well as Base Station q TSG RAN Organization v Five subgroups ü WG 1 specifying the Layer 1 ü WG 2 specifying the Signalling over the radio Interface ü WG 3 specifying the architecture and the interface within the Access Network ü WG 4 specifying the requirement for the radio performances including test specifications for Base Station ü WG 5 specifying tests for the User Equoment inclusive of the core networks aspects Confidential - 57 -

Roles of TSG WGs for LTE/SAE q TSG RAN WGs v RAN WG 1: Roles of TSG WGs for LTE/SAE q TSG RAN WGs v RAN WG 1: LTE radio layer 1 (Physical) v RAN WG 2: LTE radio layer 2/3 v RAN WG 3: Overall E-UTRAN architecture q TSG SA WGs v SA WG 1: SAE requirements based on AIPN v SA WG 2: System Architecture Evolution (SAE) v SA WG 3: LTE/SAE security q TSG CT WGs v Currently, no LTE/SAE related works Confidential - 58 -

3 GPP LTE philosophy q LTE focus is on: v enhancement of the Universal 3 GPP LTE philosophy q LTE focus is on: v enhancement of the Universal Terrestrial Radio Access (UTRA) v optimisation of the UTRAN architecture q With HSPA (downlink and uplink), UTRA will remain highly competitive for several years q LTE project aims to ensure the continued competitiveness of the 3 GPP technologies for the future q (There is also an ongoing programme of enhancements for GERAN (GSM/EDGE radio access)) Confidential - 59 -

3 GPP SAE philosophy q. SAE focus is on: venhancement of Packet Switched technology 3 GPP SAE philosophy q. SAE focus is on: venhancement of Packet Switched technology to cope with rapid growth in IP traffic ü higher data rates ü lower latency ü packet optimised system vthrough ü fully IP network ü simplified network architecture ü distributed control Confidential - 60 -

Basic criteria for LTE q Demand for higher data rates q Expectations of additional Basic criteria for LTE q Demand for higher data rates q Expectations of additional 3 G spectrum allocations q Greater flexibility in frequency allocations q Continued cost reduction q Keeping up with other (unlicensed) technologies (eg Wi. MAX) q Growing experience with the take-up of 3 G is helping to clarify the likely requirements of users, operators and service providers in the longer term Confidential - 61 -

LTE Targets q Significantly increased peak data rates q Increased cell edge bitrates q LTE Targets q Significantly increased peak data rates q Increased cell edge bitrates q Improved spectrum efficiency q Improved latency q Scaleable bandwidth q Reduced CAPEX and OPEX q Acceptable system and terminal complexity, cost and power consumption q Compatibility with earlier releases and with other systems q Optimised for low mobile speed but supporting high mobile speed Confidential - 62 -

3 GPP LTE 목적 3 GPP Long Term Evolution (LTE) q 목적/목표(Objectives) v 3 3 GPP LTE 목적 3 GPP Long Term Evolution (LTE) q 목적/목표(Objectives) v 3 GPP 기술 진화를 위해 Higher data rate, Lower latency를 지향하는 프레 임워크 개발 v. UTRAN Evolution 및 Functional Split에 초점 q RAN WGs 주축으로 진행 v. UTRAN Evolution Workshop (2004. 11. , Toronto)부터 논의 시작 v. Workshop 개최 현황 v 2004년 11월(토론토), 2005년 3월(동경), 2005년5월(퀘벡), 2005년 9 월(탈린) 3 GPP LTE 표준화 SI Phase q TSG-RAN v. TR 25. 913 (V 7. 2. 0) Requirements for Evolved UTRA and UTRAN 작성 v. TR 25. 912 (V 0. 0. 3) Feasibility Study for Evolved UTRA and UTRAN 작성 q RAN 1 v 3 GPP TR 25. 814, “Physical Layer Aspects for Evolved UTRA, ”, V 1. 0. 1(2005 -12). 작성, Study Item Phase: target 2006년 6월 Confidential - 63 -

3 GPP LTE Requirements 3 GPP LTE WG 1 무선전송기술 요구사항 q Supporting Services 3 GPP LTE Requirements 3 GPP LTE WG 1 무선전송기술 요구사항 q Supporting Services Provided from the PS-Domain q Peak Data Rate v. Max. 100 [email protected] MHz(DL), 50 [email protected] MHz (UL) v. DL: 2 RX Ant. with upto 16 -QAM, UL: 1 TX Ant with 16 QAM Bandwidth (MHz) 1. 25 2. 5 5. 0 10. 0 15. 0 20. 0 Target DL Peak Link Rate (Mbps) 6. 25 12. 5 25 50 75 100 Target UL Peak Link Rate (Mbps) 3. 125 6. 25 12. 5 25 37. 5 50 q Cell Edge Bitrate v단일 Tx/Rx 환경에서의 User throughput은 Rel. 6 HSDPA의 3 -4배, HSUPA의 2 -4배 v. Average user throughput는 2 -3배 q Spectrum Efficiency v. DL은 Rel. 6의 3 -4배, UL은 2 -3배 약 5 bps/Hz q Scalable Bandwidth v 1. 25, 2. 5, 5, 10, 15, 20 MHz Confidential - 64 -

3 GPP LTE Requirements 3 GPP LTE WG 1 무선전송기술 요구사항 q Radio Access 3 GPP LTE Requirements 3 GPP LTE WG 1 무선전송기술 요구사항 q Radio Access Network Latency v무선 액세스 네트웍의 round trip time은 10 msec 이하 (user plane UE RNC) q 이동국 속도 v저속 이동국에 최적화, 고속 이동국 지원. v음성 서비스의 경우 300 여 Km/h에서도 3 G 시스템과 동일한 품질 유지 Velocity Range Performance Characterisation 0 km/h – 15 km/h Optimal 15 km/h – 120 km/h High 120 km/h – 350 km/h Functional q 주파수 대역 v. EUTRA는 paired/unpaired 모두 가능 (FDD/TDD) q Enhanced MBMS 지원 Confidential - 65 -

3 GPP LTE Requirements 3 GPP LTE WG 1 무선전송기술 요구사항 q Coverage vup 3 GPP LTE Requirements 3 GPP LTE WG 1 무선전송기술 요구사항 q Coverage vup to 5 km: performance targets should be met. vup to 30 km: slight degradations of performance vup to 100 km: should not be precluded by the specifications q Co-existence and interworking with 3 GPP RAT Confidential - 66 -

3 GPP LTE Roadmap Confidential - 67 - 3 GPP LTE Roadmap Confidential - 67 -

3 GPP LTE Specification Status WG 1 TS 36. 201 Evolved Universal Terrestrial Radio 3 GPP LTE Specification Status WG 1 TS 36. 201 Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer; General description Ver. 0. 2. 0 TS 36. 211 Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation Ver. 0. 3. 1 TS 36. 212 Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding Ver. 0. 2. 1 TS 36. 213 Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures Ver. 0. 2. 1 TS 36. 214 Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer; Measurements Ver. 0. 1. 0 Confidential - 68 -

3 GPP LTE Specification Status WG 2 Stage 2 Evolved Universal Terrestrial Radio Access 3 GPP LTE Specification Status WG 2 Stage 2 Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access (E-UTRAN); Overall description; Stage 2 Ver. 0. 5. 0 TS 36. 302 Services provided by the physical layer Not yet TS 36. 304 UE procedures in Idle mode Not yet TS 36. 306 UE Radio Access capabilities Not yet TS 36. 321 MAC: Ericsson + Qualcomm (Magnus Lindstrom + Etienne Chaponniere) Not yet TS 36. 322 RLC: NTT Do. Co. Mo (Anil Umesh) Not yet TS 36. 323 PDCP: LG Electronics (Patrick Fischer) Not yet TS 36. 331 RRC: Samsung (Himke Vandervelde) Not yet TS 36. 300 Stage 3 Confidential - 69 -

3 GPP LTE Specification Status WG 3 Stage 3 TS 36. 401 Evolved Universal 3 GPP LTE Specification Status WG 3 Stage 3 TS 36. 401 Evolved Universal Terrestrial Radio Access (E-UTRAN); Architecture description Not yet TS 36. 410 Evolved Universal Terrestrial Radio Access (E-UTRAN); S 1 general aspects and principles Not yet TS 36. 411 Evolved Universal Terrestrial Radio Access (E-UTRAN); S 1 layer 1 Not yet TS 36. 412 Evolved Universal Terrestrial Radio Access (E-UTRAN); S 1 signalling transport Not yet TS 36. 413 Evolved Universal Terrestrial Radio Access (E-UTRAN); S 1 protocol specification Not yet TS 36. 414 Evolved Universal Terrestrial Radio Access (E-UTRAN); S 1 data transport Not yet TS 36. 420 Evolved Universal Terrestrial Radio Access (E-UTRAN); X 2 general aspects and principles Not yet TS 36. 421 Evolved Universal Terrestrial Radio Access (E-UTRAN); X 2 layer 1 Not yet TS 36. 422 Evolved Universal Terrestrial Radio Access (E-UTRAN); X 2 signalling transport Not yet TS 36. 423 Evolved Universal Terrestrial Radio Access (E-UTRAN); X 2 protocol specification Not yet TS 36. 424 Evolved Universal Terrestrial Radio Access (E-UTRAN); X 2 data transport Not yet Confidential - 70 -

3 GPP LTE Specification Status WG 4 Stage 3 TS 36. 1 ab User 3 GPP LTE Specification Status WG 4 Stage 3 TS 36. 1 ab User Equipment (UE) radio transmission and reception Not yet TS 36. 1 cd Base Station (BS) radio transmission and reception Not yet TS 36. 1 ef Requirements for support of radio resource management Not yet TS 36. 1 gh Base Station (BS) conformance testing TS 36. 9 ij E-UTRA Radio Frequency (RF) system scenarios WG 5 Stage 3 Confidential - 71 -

Part III: 3 G LTE 요소 기술 소개 Confidential - 72 - Part III: 3 G LTE 요소 기술 소개 Confidential - 72 -

Key Features of LTE q Multiple access scheme v DL: OFDMA with CP v Key Features of LTE q Multiple access scheme v DL: OFDMA with CP v UL: Single Carrier FDMA(SC-FDMA) with CP q Adaptive modulation and coding v DL modulation: QPSK, 16 QAM, and 64 QAM v UL modulation: QPSK, 16 QAM, and (64 QAM? ) v Rel-6 Turbo Code: Coding rate of 1/3, contention-free internal interleaver q Advanced MIMO spatial multiplexing techniques v (2 or 4) x (2 or 4) downlink and uplink supported ü Multi-layer transmission with up to four streams ü Multi-User MIMO also supported q ARQ within RLC and H-ARQ within MAC layer Confidential - 73 -

Key Features of LTE q Slow Power Control and link adaptation q Implicit support Key Features of LTE q Slow Power Control and link adaptation q Implicit support for interference coordination q Duplexing: FDD/TDD q Enhanced MBMS Confidential - 74 -

Basic Parameters Channel Bandwidth (Effective BW) Sampling Rate Remarks and Values 10 MHz(9 MHz) Basic Parameters Channel Bandwidth (Effective BW) Sampling Rate Remarks and Values 10 MHz(9 MHz) 20 MHz(18 MHz) 15. 36 MHz(4 x 3. 84 MHz) 30. 72 MHz(8 x 3. 84 MHz) Sub-carrier Spacing 15 k. Hz FFT Size 1024 2048 Number of Used Sub-carriers 600 1200 1 Resource Block Size 12 sub-carriers (=180 k. Hz) Confidential - 75 -

PHY Layer Transport Channels q DLTransport Channel types v Broadcast Channel (BCH) characterised by: PHY Layer Transport Channels q DLTransport Channel types v Broadcast Channel (BCH) characterised by: ü fixed, pre-defined transport format; ü requirement to be broadcast in the entire coverage area of the cell. v Downlink Shared Channel (DL-SCH) characterised by: ü support for HARQ; ü support for dynamic link adaptation by varying the modulation, coding and transmit power; ü possibility to be broadcast in the entire cell; ü possibility to use beamforming; ü support for both dynamic and semi-static resource allocation; ü support for UE discontinuous reception (DRX) to enable UE power saving; ü support for MBMS transmission (FFS). v Paging Channel (PCH) characterised by: ü support for UE discontinuous reception (DRX) to enable UE power saving (DRX cycle is indicated by the network to the UE); ü requirement to be broadcast in the entire coverage area of the cell; ü mapped to physical resources which can be used dynamically also for traffic/other control channels. v Multicast Channel (MCH) characterised by: ü requirement to be broadcast in the entire coverage area of the cell; ü support for SFN combining of MBMS transmission on multiple cells; ü support for semi-static resource allocation e. g. with a time frame of a long cyclic prefix. Confidential - 76 -

PHY Layer Transport Channels q. ULTransport Channel types v Uplink Shared Channel (UL-SCH) characterised PHY Layer Transport Channels q. ULTransport Channel types v Uplink Shared Channel (UL-SCH) characterised by: ü possibility to use beamforming; (likely no impact on specifications) ü support for dynamic link adaptation by varying the transmit power and potentially modulation and coding; ü support for HARQ; ü support for both dynamic and semi-static resource allocation. v Random Access Channel(s) (RACH) characterised by: ü limited control information; ü collision risk; ü It is FFS, whether a RACH is included. If yes, it would be characterised by the following attributes: Confidential - 77 -

Cell Search q Initial Cell Search v Find Cell Scrambling Code ID of the Cell Search q Initial Cell Search v Find Cell Scrambling Code ID of the shortest radio distance cell ü Large Number of Cell ID should be provided (~500) v Find 10 msec frame boundary ü Downlink symbol timing ü Downlink frame timing v Frequency offset estimation & Compensation v Acquiring System Information By BCH ü SFN, BW, Number of Tx antennas, and so on. Confidential - 78 -

Cell Search q Neighbor Cell Search v Find Cell Scrambling Code ID of neighboring Cell Search q Neighbor Cell Search v Find Cell Scrambling Code ID of neighboring cells v Find 10 msec frame boundary ü (Different for Async. Or Sync between BTSs) v Compare the signal strength from the neighboring cell with the home cell ü Handover procedure v Acquiring System Information by BCH ü SFN (for Async), BW q Inter-RAT measurement v GSM to LTE measurement should be satisfied : SCH symbols within 4 msec (< 4. 6 msec) interval Confidential - 79 -

MIMO Technology q MIMO-OFDM Systems ST Transmit IFFT FFT ST Receive q MIMO (multiple-input MIMO Technology q MIMO-OFDM Systems ST Transmit IFFT FFT ST Receive q MIMO (multiple-input multiple-output) v Use multiple antennas at transmitter and receiver v Provides diversity, capacity, quality q OFDM (orthogonal frequency division multiplexing) v Digital modulation scheme v Simplifies equalization in freq. sel. channels q Standards: Wi. Bro, Wi. Max, IEEE 802. 11 n, 3 Gevo Confidential - 80 -

MIMO Technology q Ideal MIMO UE Node B v Capacity of Nx. N MIMO MIMO Technology q Ideal MIMO UE Node B v Capacity of Nx. N MIMO can be N times with that of SISO q Real MIMO Node B Channel UE v N channel can be changed into m channel with different SNR by precoding Confidential - 81 -

MIMO Technology q Closed Loop versus Open Loop? Knows Channel? Transmitter channel Receiver Estimates MIMO Technology q Closed Loop versus Open Loop? Knows Channel? Transmitter channel Receiver Estimates Channel feedback? q Open loop communication v Transmit signals designed independently of channel q Closed loop communication v Transmit signals designed as a function of channel Confidential - 82 -

MIMO Technology q How to Close Loop with FDD ST Transmit Reconstruct ST Estimate MIMO Technology q How to Close Loop with FDD ST Transmit Reconstruct ST Estimate Receive feedback Channel Quantizer q Frequency division duplex (FDD) v Use same frequency for uplink / downlink q How FDD provides channel state information v Through a feedback channel q Issues v Feedback channel bandwidth is limited (5 - 10 bits/update) v Quantization, delay and errors in feedback channel Confidential - 83 -

MIMO Technology q Feedback in MIMO-OFDM is Hard q PHY: # of physical channel MIMO Technology q Feedback in MIMO-OFDM is Hard q PHY: # of physical channel coefficients is high Mt * Mr * N v Number of transmit antennas v Number of receive antennas v Number of tones N (or extent of multi-path) q MAC+: Channels required for all active users for most gain v Need control channels to convey this information Confidential - 84 -

MIMO Technology q Overview of LTE MIMO Schemes v Closed-loop MIMO schemes for unicast MIMO Technology q Overview of LTE MIMO Schemes v Closed-loop MIMO schemes for unicast traffic ü Basic features – MCW transmission – Precoding – Rank adaptation – Single user/ Multiuser MIMO ü Proposed schemes – Qualcomm – Samsung – Intel v Open-loop Tx diversity ü SF(T)BC ü CDD ü Combined CDD/SF(T)BC Confidential - 85 -

MIMO Technology q Multicodeword transmission v Transmission of multiple parallel streams ü Independent coding MIMO Technology q Multicodeword transmission v Transmission of multiple parallel streams ü Independent coding for each stream ü Per stream rate control ü Known to achieve open-loop MIMO capacity when combined with stream-by-stream SIC reception Confidential - 86 -

MIMO Technology q Precoding matrix P (M x K) v. M = number of MIMO Technology q Precoding matrix P (M x K) v. M = number of Tx antennas v. K = number of independent input symbols (Rank) Original symbols Precoded symbols, Transmitted by M Tx antennas Precoding vectors Confidential - 87 -

MIMO Technology q Precoding & Rank adaptation v Precoding ü Precoding to each stream MIMO Technology q Precoding & Rank adaptation v Precoding ü Precoding to each stream (phase and amplitude variation across transmit antennas) ü Choice of precoding matrices (or vectors) depending on cell environment and UE channel v Rank adaptation ü Adaptation of the number of independent symbols ü The rank is determined by the UE. ü Only for single-user MIMO mode Confidential - 88 -

MIMO Technology q Single-user MIMO schemes v v PARC, S-PARC etc. All streams to MIMO Technology q Single-user MIMO schemes v v PARC, S-PARC etc. All streams to one user Stream-by-stream SIC Spatial domain multiuser diversity is NOT available q Multi-user MIMO schemes v v PU 2 RC Multistreams to multiple users Spatial domain multiuser diversity Larger diversity gain than single-user MIMO v Stream-by-stream SIC is NOT available Single-user MIMO Multi-user MIMO Confidential - 89 -

RACH q RACH? v Random Access Channel ü Contention based(ALOHA) ü Scheduled based v RACH q RACH? v Random Access Channel ü Contention based(ALOHA) ü Scheduled based v When UE needs uplink resource q Non-synch RACH v When UE does not synchronized with uplink timing v Guard time is needed v Good auto correlation to estimate exact timing q Synch RACH v When UE already have uplink timing Confidential - 90 -

RACH q Uplink timing(Round Trip Delay) v Downlink timing can be acquired by SCH RACH q Uplink timing(Round Trip Delay) v Downlink timing can be acquired by SCH for each UE v Uplink timing can not be acquired without feedback from Node. B UE A UE B Node B RTD = 2 * Distance / C(light of speed) SCH signal UE A UE B Node B UE A Downlink timing Uplink signal UE B Confidential - 91 -