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An Introduction of 3GPP Long Term Evolution (LTE) Speaker : Tsung-Yin Lee.

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Presentation on theme: "An Introduction of 3GPP Long Term Evolution (LTE) Speaker : Tsung-Yin Lee."— Presentation transcript:

1 An Introduction of 3GPP Long Term Evolution (LTE) Speaker : Tsung-Yin Lee

2 2 Reference “LTE-Advanced: Future of Mobile Broadband,” TATA Consultancy Services 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 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

3 3 Outline History of 3GPP LTE Basic Concepts of LTE Introduction of LTE Protocol Compare with LTE and LTE-Advanced Conclusion

4 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

5 5 Evolution of Radio Access Technologies LTE (3.9G) : 3GPP release 8~9 LTE-Advanced : 3GPP release d/e m

6 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

7 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)

8 8 Equalizers in Receiver Against Frequency Selective Fading Channel transform function H c (f) Equalizers transform function H eq (f) (Receiver)

9 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

10 10 Cyclic Prefixes

11 11 FDM vs. OFDM

12 12 LTE-Downlink (OFDM) Improved spectral efficiency Reduce ISI effect by multipath Against frequency selective fading

13 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

14 14 Multi-antenna techniques

15 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)

16 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

17 17 LTE spectrum (bandwidth and duplex) flexibility

18 18 LTE Downlink Channels Paging Channel Paging Control Channel Physical Downlink Shared Channel

19 19 LTE Uplink Channels Random Access Channel Physical Radio Access Channel Physical Uplink Shared Channel CQI report

20 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

21 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

22 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

23 23 Asymmetric transmission bandwidth Symmetric transmission voice transmission : UE to UE Asymmetric transmission streaming video : the server to the UE (the downlink)

24 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

25 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

26 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

27 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

28 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

29 29 LTE vs. LTE-Advanced

30 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

31 31 Backup

32 32 LTE Downlink Logical Channels

33 33 LTE Downlink Logical Channels

34 34 LTE Downlink Transport Channel

35 35 LTE Downlink Transport Channel

36 36 LTE Downlink Physical Channels

37 37 LTE Downlink Physical Channels

38 38 LTE Uplink Logical Channels

39 39 LTE Uplink Transport Channel

40 40 LTE Uplink Physical Channels


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