An Introduction of 3GPP Long Term Evolution (LTE)

1. An Introduction of3GPP Long Term Evolution (LTE) Speaker：Tsung-Yin Lee

2. Reference • http://www.tcs.com “LTE-Advanced: Future of Mobile Broadband,” TATA Consultancy Services • Takehiro Nakamura ,“Proposal for Candidate Radio Interface Technologies 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

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

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. Evolution of Radio Access Technologies • LTE (3.9G) : 3GPP release 8~9 • LTE-Advanced :3GPP release 10+ 802.16m 802.16d/e

6. LTE Basic Concepts • LTE employs OrthogonalFrequency Division Multiple Access (OFDMA) for downlink data transmission and Single Carrier FDMA (SC-FDMA) for uplink transmission

7. Multipath-Induced Time Delays Result in Inter-Symbol Interference (ISI) βS(t-m) S(t) y(t) : output signal S(t) : input signal S(t-m) : delayed m time input signal n(t) : noise y(t)

8. Equalizers in Receiver • Against Frequency Selective Fading • Channel transform function Hc(f) • Equalizers transform function Heq(f) (Receiver)

9. Frequency Selective Fading • the coherence bandwidth of the channel is smaller than the bandwidth of the signal Frequency Correlation > 0.9 Bc = 1 / 50α α is r.m.s. delay spread It may be useless for increasing transmission power

10. Cyclic Prefixes

11. FDM vs. OFDM

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

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. Multi-antenna techniques

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. 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. LTE spectrum (bandwidth and duplex) flexibility

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

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

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

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. 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. 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. 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. 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. LTE vs. LTE-Advanced

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. Backup

32. LTE Downlink Logical Channels

33. LTE Downlink Logical Channels

34. LTE Downlink Transport Channel

35. LTE Downlink Transport Channel

36. LTE Downlink Physical Channels

37. LTE Downlink Physical Channels

38. LTE Uplink Logical Channels

39. LTE Uplink Transport Channel

40. LTE Uplink Physical Channels