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An Introduction of 3GPP Long Term Evolution (LTE) Speaker : Tsung-Yin Lee
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2 Reference http://www.tcs.com “LTE-Advanced: Future of Mobile Broadband,” TATA Consultancy Services http://www.tcs.com Takehiro Nakamura,“Proposal for Candidate Radio Interface Technol ogies for IMT ‐ Advanced Bas d on LTE Release 10 and Beyond,” 3GPP TSG ‐ RAN Chairman “3GPP LTE Channels and MAC Layer,” EventHelix.com Inc. 2009 Ahmed Hamza, Network Systems Laboratory Simon Fraser University, “Long Term Evolution (LTE) - A Tutorial,” October 13, 2009 Jim Zyren, “Overview of the 3GPP Long Term Evolution Physical Layer,” Document Number: 3GPP EVOLUTIONWP Rev0 07/2007 David Astély, Erik Dahlman, Anders Furuskär, Ylva Jading, Magnus Lindström, and Stefan Parkvall, Ericsson Research, “LTE: The Evolution of Mobile Broadband”, IEEE Communications Magazine, April 2009
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3 Outline History of 3GPP LTE Basic Concepts of LTE Introduction of LTE Protocol Compare with LTE and LTE-Advanced Conclusion
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4 What is LTE ? In Nov. 2004, 3GPP began a project to define the long-term evolution (LTE) of Universal Mobile Telecommunications System (UMTS) cellular technology Higher performance Backwards compatible Wide application
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5 Evolution of Radio Access Technologies LTE (3.9G) : 3GPP release 8~9 LTE-Advanced : 3GPP release 10+ 802.16d/e 802.16m
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6 LTE Basic Concepts LTE employs Orthogonal Frequency Division Multiple Access (OFDMA) for downlink data transmission and Single Carrier FDMA (SC-FDMA) for uplink transmission
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7 Multipath-Induced Time Delays Result in Inter-Symbol Interference (ISI) y(t) : output signal S(t) : input signal S(t-m) : delayed m time input signal n(t) : noise y(t) βS (t-m) S (t)
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8 Equalizers in Receiver Against Frequency Selective Fading Channel transform function H c (f) Equalizers transform function H eq (f) (Receiver)
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9 Frequency Selective Fading the coherence bandwidth of the channel is smaller than the bandwidth of the signal It may be useless for increasing transmission power Frequency Correlation > 0.9 B c = 1 / 50α α is r.m.s. delay spread
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10 Cyclic Prefixes
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11 FDM vs. OFDM
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12 LTE-Downlink (OFDM) Improved spectral efficiency Reduce ISI effect by multipath Against frequency selective fading
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13 LTE Uplink (SC-FDMA) SC-FDMA is a new single carrier multiple access technique which has similar structure and performance to OFDMA A salient advantage of SC- FDMA over OFDM is low to Peak to Average Power Ratio (PAPR) : Increasing battery life
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14 Multi-antenna techniques
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15 Generic Frame Structure Allocation of physical resource blocks (PRBs) is handled by a scheduling function at the 3GPP base station (eNodeB) Frame 0 and frame 5 (always downlink)
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16 Resource Grid One frame is 10ms 10 subframes One subframe is 1ms 2 slots One slot is 0.5ms N resource blocks [ 6 < N < 110] One resource block is 0.5ms and contains 12 subcarriers from each OFDM symbol
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17 LTE spectrum (bandwidth and duplex) flexibility
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18 LTE Downlink Channels Paging Channel Paging Control Channel Physical Downlink Shared Channel
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19 LTE Uplink Channels Random Access Channel Physical Radio Access Channel Physical Uplink Shared Channel CQI report
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20 LTE Release 8 Key Features (1/2) High spectral efficiency OFDM in Downlink Single ‐ Carrier FDMA in Uplink Very low latency Short setup time & Short transfer delay Short hand over latency and interruption time Support of variable bandwidth 1.4, 3, 5, 10, 15 and 20 MHz
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21 LTE Release 8 Key Features (2/2) Compatibility and interworking with earlier 3GPP Releases FDD and TDD within a single radio access technology Efficient Multicast/Broadcast
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22 Evolution of LTE-Advanced Asymmetric transmission bandwidth Layered OFDMA Advanced Multi-cell Transmission/Reception Techniques Enhanced Multi-antenna Transmission Techniques Support of Larger Bandwidth in LTE- Advanced
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23 Asymmetric transmission bandwidth Symmetric transmission voice transmission : UE to UE Asymmetric transmission streaming video : the server to the UE (the downlink)
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24 Layered OFDMA The bandwidth of basic frequency block is, 15–20 MHz Layered OFDMA radio access scheme in LTE-A will have layered transmission bandwidth, support of layered environments and control signal formats
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25 Advanced Multi-cell Transmission/Reception Techniques In LTE-A, the advanced multi-cell transmission/reception processes helps in increasing frequency efficiency and cell edge user throughput Estimation unit Calculation unit Determination unit Feedback unit
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26 Enhanced Multi-antenna Transmission Techniques In LTE-A, the MIMO scheme has to be further improved in the area of spectrum efficiency, average cell through put and cell edge performances In LTE-A the antenna configurations of 8x8 in DL and 4x4 in UL are planned
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27 Enhanced Techniques to Extend Coverage Area Remote Radio Requirements (RREs) using optical fiber should be used in LTE-A as effective technique to extend cell coverage
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28 Support of Larger Bandwidth in LTE-Advanced Peak data rates up to 1Gbps are expected from bandwidths of 100MHz. OFDM adds additional sub-carrier to increase bandwidth
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29 LTE vs. LTE-Advanced
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30 Conclusion LTE-A helps in integrating the existing networks, new networks, services and terminals to suit the escalating user demands LTE-Advanced will be standardized in the 3GPP specification Release 10 (LTE-A) and will be designed to meet the 4G requirements as defined by ITU
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31 Backup
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32 LTE Downlink Logical Channels
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33 LTE Downlink Logical Channels
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34 LTE Downlink Transport Channel
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35 LTE Downlink Transport Channel
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36 LTE Downlink Physical Channels
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37 LTE Downlink Physical Channels
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38 LTE Uplink Logical Channels
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39 LTE Uplink Transport Channel
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40 LTE Uplink Physical Channels
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