1 / 66

LTE: Evolution, Standards, and Technology Overview

Dive into the world of LTE with this course unit covering its history, features, major requirements, and evolution. Explore LTE-Advanced, OFDMA, SC-FDMA, frame structures, and more.

jmark
Download Presentation

LTE: Evolution, Standards, and Technology Overview

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 教育部補助「行動寬頻尖端技術跨校教學聯盟第二期計畫--行動寬頻網路與應用--小細胞基站聯盟中心」EPC核心網路系統設計課程單元 04：LTE 通訊與協定 計畫主持人：許蒼嶺 (國立中山大學 電機工程學系) 授課教師：萬欽德 (國立高雄第一科技大學 電腦與通訊工程系)

  2. LTE • LTE • A standard for mobile data communications technology • An evolution of the GSM/UMTS standards • However, LTE wireless interface • Incompatible with 2G and 3G networks • Must be operated on a separate wireless spectrum

  3. History of LTE • LTE was first proposed by NTT DoCoMoof Japan in 2004, and studies on the new standard officially commenced in 2005. • The LTE standard was finalized in December 2008. • The first publicly available LTE service was launched by TeliaSonera in Oslo and Stockholm on December 14, 2009 as a data connection with a USB modem. • Samsung Galaxy Indulge: the world’s first LTE smartphone starting (February 10, 2011).

  4. History of LTE (Cont’d) • Initially, CDMA operators planned to upgrade to rival standards called UMB and WiMAX. • But all the major CDMA operators have announced that they intend to migrate to LTE after all. • Verizon, Sprint and MetroPCS in the United States • Bell and Telus in Canada • KDDI in Japan • SK Telecom in South Korea • China Telecom/China Unicom in China

  5. LTE-Advanced (LTE-A) • The evolution of LTE is LTE Advanced • was standardized in March 2011. • Services of LTE Advanced commenced in 2013.

  6. Features of LTE • Increase of capacity and speed of wireless data networks using new DSPand modulation techniques. • Redesign and simplification of the network architecture to an IP-based system • Reduced transfer latency compared to the 3G architecture

  7. Major Requirements for LTE • Higher peak data rates: 100 Mbps (downlink) and 50 Mbps (uplink) • Improved spectrum efficiency: 2-4 times better compared to 3GPP release 6 • Improved latency: • Radio access network latency (user plane UE – RNC –UE) below 10 ms • Significantly reduced control plane latency • Support of scalable bandwidth: 1.4, 3, 5, 10, 15, 20 MHz • Support of paired and unpaired spectrum (FDD and TDD mode) • Support for interworking with legacy networks

  8. Evolution of UMTS FDD and TDD

  9. Data Transmission in LTE • Downlink: • OrthogonalFrequency Division Multiple Access (OFDMA) • Uplink: • Single Carrier FDMA (SC-FDMA): • SC-FDMA: • a new single carrier multiple access technique • has similar structure and performance to OFDMA • Advantage of SC-FDMA over OFDM: • Low Peak to Average Power ratio (PAPR) : Increasing battery life

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

  11. Introduction to OFDMA Downlink Frame Structure

  12. What is OFDM

  13. OFDM Signal Generation Chain OFDM signal generation is based on Inverse Fast Fourier Transform (IFFT) operation on transmitter side: On receiver side, an FFT operation will be used.

  14. Difference between OFDM and OFDMA

  15. OFDMA Time-Frequency Multiplexing

  16. LTE – Spectrum Flexibility

  17. Introduction to SC-FDMA Uplink Frame Structure

  18. SC-FDMA Signal Generation Chain DFT “pre-coding” is performed on modulated data symbols Sub-carrier mapping allows flexible allocation of signal to available sub-carriers IDFT and cyclic prefix (CP) insertion as in OFDM. Each subcarrier carries a portion of superposed DFT spread data symbols, therefore SC-FDMA is also referred to as DFT-spread-OFDM (DFT-s-OFDM).

  19. OFDM Signal Generation Chain OFDM signal generation is based on Inverse Fast Fourier Transform (IFFT) operation on transmitter side: On receiver side, an FFT operation will be used.

  20. OFDMA (DL) vs. SC-FDMA (UL) 1/2 OFDMA: each sub-carrier only carries information related to one specific symbol SC-FDMA: each sub-carrier contains information of ALL transmitted symbols

  21. OFDMA (DL) vs. SC-FDMA (UL) 2/2

  22. Radio Procedure

  23. LTE Initial Access

  24. Cell Search in LTE (1/4)

  25. Cell Search in LTE: Reference Signals (2/4)

  26. Downlink Reference Signals (3/4)

  27. Cell Search:Essential System Information (4/4)

  28. LTE Initial Access

  29. How to derive Information

  30. LTE Initial Access

  31. Indicating PDCCH Format

  32. Uplink Physical Channels and Signals

  33. Scheduling of Uplink Data

  34. Acknowledging UL data packets on PHICH

  35. Generic Frame Structure • Allocation of physical resource blocks (PRBs) • Scheduling at the 3GPP base station: Evolved Node B (eNodeB)

  36. Frame Structure (DwPTS field) • DwPTS field: • The downlink part of the special subframe • Its length can be varied from three up to twelve OFDM symbols.

  37. Frame Structure (UpPTSfield) • UpPTSfield: • The uplink part of the special subframe • It has a short duration with one or two OFDM symbols.

  38. Frame Structure (GP field) • GPfield: • The remaining symbols (not allocated to DwPTS or UpPTS) in the special subframe. • Providing the guard period.

  39. Resource Blocks for OFDMA • One frame: 10 ms (with 10 subframes) • One subframe: 1ms (with 2 slots) • One slot: N Resource Blocks (6 < N < 110) • The number of downlink resource blocks depends on the transmission bandwidth. • One Resource Block: M subcarriers for each OFDM symbol • M depends on the subcarrier spacing Δf • The number of OFDM symbols in each block depends on both the CP length and the subcarrier spacing.

  40. LTE Spectrum (Bandwidth and Duplex) Flexibility

  41. LTE Downlink Channels • The LTE radio interface: • Various "channels" are used. • Channels are used to segregate the different types of data and allow them to be transported across the radio access network in an orderly fashion. • Physical channels: transmission channels that carry user data and control messages. • Transport channels: the physical layer transport channels offer information transfer to Medium Access Control (MAC) and higher layers. • Logical channels: provide services for the MAC layer within the LTE protocol structure.

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

  43. LTE Downlink Logical Channels

  44. LTE Downlink Logical Channels

  45. LTE Downlink Transport Channel

  46. LTE Downlink Transport Channel

  47. LTE Downlink Physical Channels

More Related