An Introduction of 3 GPP Long Term Evolution

An Introduction of 3 GPP Long Term Evolution (LTE)

Outline § § § History of 3 GPP LTE Basic Concepts of LTE Introduction of LTE Protocol Compare with LTE and LTE-Advanced Conclusion 2

What is LTE ? § In Nov. 2004, 3 GPP (3 rd Generation Partnership Project) began a project to define the Long-Term Evolution (LTE) of Universal Mobile Telecommunications System (UMTS) cellular technology Ø Higher performance Ø Backwards compatible Ø Wide applications 3

History of LTE § LTE is a standard for wireless data communications technology and an evolution of the GSM/UMTS standards. § The goal of LTE was to increase the capacity and speed of wireless data networks using new DSP (digital signal processing) techniques and modulations. § A further goal was the redesign and simplification of the network architecture to an IP-based system with significantly reduced transfer latency compared to the 3 G architecture. § The LTE wireless interface is incompatible with 2 G and 3 G networks, so that it must be operated on a separate wireless spectrum. 4

History of LTE(Cont’d) § LTE was first proposed by NTT Do. Co. Mo of Japan in 2004, and studies on the new standard officially commenced in 2005. § The LTE standard was finalized in December 2008, and the first publicly available LTE service was launched by Telia. Sonera in Oslo and Stockholm on December 14, 2009 as a data connection with a USB modem. § Samsung Galaxy Indulge being the world’s first LTE smartphone starting on February 10, 2011. 5

History of LTE(Cont’d) § Initially, CDMA operators planned to upgrade to rival standards called UMB and Wi. MAX § But all the major CDMA operators (such as Verizon, Sprint and Metro. PCS in the United States, Bell and Telus in Canada, au by KDDI in Japan, SK Telecom in South Korea and China Telecom/China Unicom in China) have announced that they intend to migrate to LTE after all. § The evolution of LTE is LTE Advanced, which was standardized in March 2011. Services are expected to commence in 2013. 6

Evolution of Radio Access Technologies 802. 16 m 802. 16 d/e n n LTE (3. 9 G) : 3 GPP release 8~9 LTE-Advanced : 3 GPP release 10+ 7

LTE Basic Concepts n n n LTE employs Orthogonal Frequency Division Multiple Access (OFDMA) for downlink data transmission and Single Carrier FDMA (SCFDMA) for uplink transmission 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 the low Peak to Average Power (PAP) ratio : Increasing battery life 8

LTE Uplink (SC-FDMA) 9

Multi-Antenna Techniques 10

Generic Frame Structure n Allocation of physical resource blocks (PRBs) is handled by a scheduling function at the 3 GPP base station: Evolved Node B (e. Node. B) Frame 0 and frame 5 (always downlink) 11

Generic Frame Structure (Cont’d) n n n Dw. PTS field: This is the downlink part of the special subframe and its length can be varied from three up to twelve OFDM symbols. The Up. PTS field: This is the uplink part of the special subframe and has a short duration with one or two OFDM symbols. The GP field: The remaining symbols in the special subframe that have not been allocated to Dw. PTS or Up. PTS are allocated to the GP field, which is used to provide the guard period for the downlink-touplink and the uplink-to-downlink switch. 12

Resource Blocks for OFDMA n n n One frame is 10 ms consisting of 10 subframes One subframe is 1 ms with 2 slots One slot contains N Resource Blocks (6 < N < 110) Ø n One Resource Block contains M subcarriers for each OFDM symbol Ø n The number of downlink resource blocks depends on the transmission bandwidth. The number of subcarriers in each resource block depends on the subcarrier spacing Δf The number of OFDM symbols in each block depends on both the CP length and the subcarrier spacing. 13

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LTE Spectrum (Bandwidth and Duplex) Flexibility 15

LTE Downlink Channels n n The LTE radio interface, various "channels" are used. These 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: These are 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 Medium Access Control (MAC) layer within the LTE protocol structure. 16

LTE Downlink Channels Paging Control Channel Paging Channel Physical Downlink Shared Channel 17

LTE Downlink Logical Channels 18

LTE Downlink Logical Channels 19

LTE Downlink Transport Channel 20

LTE Downlink Transport Channel 21

LTE Downlink Physical Channels 22

LTE Downlink Physical Channels 23

LTE Uplink Channels Random Access Channel CQI report Physical Uplink Shared Channel Physical Radio Access Channel 24

LTE Uplink Logical Channels 25

LTE Uplink Transport Channel 26

LTE Uplink Physical Channels 27

LTE Release 8 Key Features (1/2) n n n High spectral efficiency Ø OFDM in Downlink Ø Single‐Carrier FDMA in Uplink Very low latency Ø Short setup time & Short transfer delay Ø Short hand over latency and interruption time Support of variable bandwidth Ø 1. 4, 3, 5, 10, 15 and 20 MHz 28

LTE Release 8 Key Features (2/2) n n n Compatibility and interworking with earlier 3 GPP FDD and TDD within a single radio access technology Efficient Multicast/Broadcast 29

Evolution of LTE-Advanced n n n Asymmetric transmission bandwidth Layered OFDMA Advanced Multi-cell Transmission/Reception Techniques Enhanced Multi-antenna Transmission Techniques Support of Larger Bandwidth in LTE-Advanced 30

Asymmetric Transmission Bandwidth n Symmetric transmission n n Voice transmission: UE to UE Asymmetric transmission n Streaming video : the server to the UE (the downlink) 31

Layered OFDMA n n 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. 32

Coordinated Multi-Point Transmission/Reception (Co. MP) n The Co. MP 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. 33

Enhanced Multi-Antenna Transmission Techniques n n 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 8 x 8 in DL and 4 x 4 in UL are planned 34

Enhanced Techniques to Extend Coverage Area n Remote Radio Requirements (RREs) using optical fiber should be used in LTE-A as effective technique to extend cell coverage 35

Support of Larger Bandwidth in LTE-Advanced n Peak data rates up to 1 Gbps are expected from bandwidths of 100 MHz. OFDM adds additional sub-carrier to increase bandwidth 36

LTE vs. LTE-Advanced 37

Conclusion n n 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 3 GPP specification Release 10 (LTE-A) and will be designed to meet the 4 G requirements as defined by ITU 38