Demystified LTE

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LTE theory and explanation

Transcript of Demystified LTE

  • An Introduction of3GPP Long Term Evolution (LTE)

  • *OutlineHistory of 3GPP LTEBasic Concepts of LTEIntroduction of LTE ProtocolCompare with LTE and LTE-AdvancedConclusion

  • *What is LTE ?In Nov. 2004, 3GPP (3rd Generation Partnership Project) began a project to define the Long-Term Evolution (LTE) of Universal Mobile Telecommunications System (UMTS) cellular technologyHigher performanceBackwards compatibleWide applications

    3rd Generation Partnership Project3GPP199812ETSIARIBTTCCCSATTAATIS*

  • History of LTELTE 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 3G architecture. The LTE wireless interface is incompatible with 2G and 3G networks, so that it must be operated on a separate wireless spectrum.*

  • History of LTE(Contd)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, and 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 being the worlds first LTE smartphone starting on 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*

  • History of LTE(Contd)Initially, CDMA operators planned to upgrade to rival standards called UMB and WiMAX But all the major CDMA operators (such as Verizon, Sprint and MetroPCS 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.*

  • *Evolution of Radio Access TechnologiesLTE (3.9G) : 3GPP release 8~9LTE-Advanced :3GPP release 10+

    802.16d/e802.16m

  • *

    LTE Basic ConceptsLTE employs Orthogonal Frequency Division Multiple Access (OFDMA) for downlink data transmission and Single Carrier FDMA (SC-FDMA) for uplink transmissionSC-FDMA is a new single carrier multiple access technique which has similar structure and performance to OFDMAA salient advantage of SC-FDMA over OFDM is the low Peak to Average Power (PAP) ratio : Increasing battery life

  • *LTE Uplink (SC-FDMA)

  • *Multi-Antenna Techniques

  • *Generic Frame StructureAllocation of physical resource blocks (PRBs) is handled by a scheduling function at the 3GPP base station: Evolved Node B (eNodeB)

    Frame 0 and frame 5 (always downlink)

  • Generic Frame Structure (Contd)DwPTS field: This is the downlink part of the special subframe and its length can be varied from three up to twelve OFDM symbols.The UpPTS 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 DwPTS or UpPTS are allocated to the GP field, which is used to provide the guard period for the downlink-to-uplink and the uplink-to-downlink switch.

    *

  • Resource Blocks for OFDMAOne frame is 10 ms consisting of 10 subframesOne subframe is 1ms with 2 slotsOne slot contains N Resource Blocks (6 < N < 110)

    The number of downlink resource blocks depends on the transmission bandwidth.One Resource Block contains M subcarriers for each OFDM symbol

    The number of subcarriers in each resource block depends on the subcarrier spacing fThe number of OFDM symbols in each block depends on both the CP length and the subcarrier spacing.

    *

  • *

  • *LTE Spectrum (Bandwidth and Duplex) Flexibility

  • LTE Downlink ChannelsThe 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.

    *

    Physical ChannelUEEnodeBResourse Block(RB)RB *

  • *LTE Downlink ChannelsPaging ChannelPaging Control ChannelPhysical Downlink Shared Channel

  • *LTE Downlink Logical Channels

    UE: User EquipmentRRC: Radio Resource Control*

  • *LTE Downlink Logical Channels

    MBMS: Multimedia Broadcast Multicast Services *

  • *LTE Downlink Transport Channel

  • *LTE Downlink Transport Channel

  • *LTE Downlink Physical Channels

  • *LTE Downlink Physical Channels

  • *LTE Uplink ChannelsRandom Access ChannelPhysical Radio Access ChannelPhysical Uplink Shared ChannelCQI report

  • *LTE Uplink Logical Channels

  • *LTE Uplink Transport Channel

  • *LTE Uplink Physical Channels

  • *LTE Release 8 Key Features (1/2)Highspectralefficiency

    OFDM inDownlinkSingleCarrierFDMAinUplinkVerylowlatency

    Shortsetuptime&ShorttransferdelayShorthand overlatencyandinterruptiontimeSupportofvariablebandwidth

    1.4,3,5,10,15and20MHz

  • *LTE Release 8 Key Features (2/2)Compatibilityandinterworkingwithearlier 3GPPFDDandTDDwithinasingleradioaccess technology EfficientMulticast/Broadcast

  • *Evolution of LTE-AdvancedAsymmetric transmission bandwidthLayered OFDMAAdvanced Multi-cell Transmission/Reception TechniquesEnhanced Multi-antenna Transmission TechniquesSupport of Larger Bandwidth in LTE-Advanced

  • *Asymmetric Transmission BandwidthSymmetric transmissionVoice transmission: UE to UE Asymmetric transmissionStreaming video : the server to the UE (the downlink)

  • *Layered OFDMAThe bandwidth of basic frequency block is, 15 - 20 MHzLayered 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.

  • *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.

  • *Enhanced Multi-Antenna Transmission TechniquesIn LTE-A, the MIMO scheme has to be further improved in the area of spectrum efficiency, average cell through put and cell edge performancesIn LTE-A the antenna configurations of 8x8 in DL and 4x4 in UL are planned

  • *Enhanced Techniques to Extend Coverage AreaRemote Radio Requirements (RREs) using optical fiber should be used in LTE-A as effective technique to extend cell coverage

  • *Support of Larger Bandwidth in LTE-AdvancedPeak data rates up to 1Gbps are expected from bandwidths of 100MHz. OFDM adds additional sub-carrier to increase bandwidth

  • *LTE vs. LTE-Advanced

  • *ConclusionLTE-A helps in integrating the existing networks, new networks, services and terminals to suit the escalating user demandsLTE-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

    3rd Generation Partnership Project3GPP199812ETSIARIBTTCCCSATTAATIS*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*Physical ChannelUEEnodeBResourse Block(RB)RB *UE: User EquipmentRRC: Radio Resource Control*MBMS: Multimedia Broadcast Multicast Services *