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 However, LTE wireless interface
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 DoCoMo of 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).
On June 25th, 2013, Korea's SK Telecom announced the launching of LTE-Advanced services in Korea. [15]
On June 26th, 2013, Samsung Electronics released an LTE-Advanced version of the Galaxy S4. [16]
On July 18th, 2013, Korea's LG U Plus unveiled an LTE-Advanced network.[17]
On August 18th, 2013, Philippines’ SMART Communications tests the LTE-Advanced network.[18]
On November 5th 2013, two major carriers in the United Kingdom (Vodafone and EE) announced they would be holding LTE - A trials in the London area.
On November 15th 2013, Telefonica and Vodafone have announced that they are testing LTE-Advanced in the German cities of Munich and Dresden

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 DSP and 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

10. Data Transmission in LTE
Downlink:
Orthogonal Frequency 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

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

13. Introduction to OFDMA
Downlink Frame Structure

14. What is OFDM

15. 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.

16. Difference between OFDM and OFDMA

17. OFDMA Time-Frequency Multiplexing

18. LTE – Spectrum Flexibility

19. Introduction to SC-FDMA
Uplink Frame Structure

20. 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).

21. 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.

22. 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

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

24. Radio Procedure

25. LTE Initial Access

26. Cell Search in LTE (1/4)

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

28. Downlink Reference Signals (3/4)

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

30. LTE Initial Access

31. How to derive Information

32. LTE Initial Access

33. Indicating PDCCH Format

34. Uplink Physical Channels and Signals

35. Scheduling of Uplink Data

36. Acknowledging UL data packets on PHICH

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

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

39. Frame Structure (UpPTS field)
The uplink part of the special subframe
It has a short duration with one or two OFDM symbols.

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

41. 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.

43. LTE Spectrum (Bandwidth and Duplex) Flexibility

44. 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.
Physical Channel，乘載上層資訊並送出訊號給UE或EnodeB，簡單的說就是將Resourse Block(RB)分配的機制，規定每一個RB要做為什麼用途，會介紹這個是為了延續上篇介紹的主題。

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

46. LTE Downlink Logical Channels
UE: User Equipment
RRC: Radio Resource Control

47. LTE Downlink Logical Channels
MBMS: Multimedia Broadcast Multicast Services

48. LTE Downlink Transport Channel

49. LTE Downlink Transport Channel

50. LTE Downlink Physical Channels

51. LTE Downlink Physical Channels

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

53. LTE Uplink Logical Channels

54. LTE Uplink Transport Channel

55. LTE Uplink Physical Channels

56. 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

57. LTE Release 8 Key Features (2/2)
Compatibility and interworking with earlier 3GPP
FDD and TDD within a single radio access technology
Efficient Multicast/Broadcast

58. 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

59. Symmetric and Asymmetric Transmission Bandwidth
Voice transmission: UE to UE
Asymmetric transmission
Streaming video : the server to the UE (the downlink)

60. Layered OFDMA The bandwidth of basic frequency block is, 15 - 20 MHz
Layered OFDMA comprises layered transmission bandwidth assignment (bandwidth is assigned to match the required data rate), a layered control signaling structure, and support for layered environments for both the downlink and uplink.

61. Coordinated Multi-Point Transmission/Reception (CoMP)
The CoMP is one of the candidate techniques for LTE-Advanced systems to increase the average cell throughput and cell edge user throughput in the both uplink and downlink.

62. Enhanced Multi-Antenna Transmission Techniques
In LTE-A, the MIMO scheme has to be further improved in the area of spectrum efficiency, average cell throughput and cell edge performances
In LTE-A the antenna configurations of 8x8 in DL and 4x4 in UL are planned

63. 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

64. 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

65. LTE vs. LTE-Advanced

66. Summary
LTE-A helps in integrating the existing networks, new networks, services and terminals to suit the escalating user demands
LTE-Advanced was standardized in the 3GPP specification Release 10 (LTE-A) and designed to meet the 4G requirements as defined by ITU