Long Term Evolution (LTE) Technology

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Long Term Evolution (LTE) Technology. Presented by GHANSHYAM MISHRA 11EC63R22 M.Tech, RF & Microwave Engineering IIT KHARAGPUR. OUTLINE:. Generation of wireless mobile technologies Targets for LTE LTE architecture LTE enabling technologies: OFDM - PowerPoint PPT Presentation

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Long term evolution (lte) technology

Long Term Evolution (LTE) Technology

Presented by GHANSHYAM MISHRA 11EC63R22M.Tech,RF & Microwave EngineeringIIT KHARAGPUR.OUTLINE:Generation of wireless mobile technologies

Targets for LTE

LTE architecture

LTE enabling technologies: OFDM MIMO antenna technology

Continued.Spectrum for LTE deployments

Comparative study of 3GPP LTE and Wi-MAX

LTE network performance

LTE- Advanced


GENERATION OF WIRELESS MOBILE COMMUNICATION GENERATIONFEATURESTHROUGHPUTTECHNOLOGY1 GAnalog14.4 Kbps(peak)AMPS2 GDigital , Narrowband, Circuit switched data 9.6/14.4 KbpsTDMA(IS-136), GSM, CDMA (IS-95)2.5 GPacket switched data171.2 Kbps(peak)20-40 KbpsGPRS3 GDigital, broadband and packet data3.1Mbps(peak)500-700KbpsCDMA 2000, UMTSEDGE3.5 G> 2 MbpsUpto 3.6/7.2/14.4 Mbps(peak)1-3 Mbps

HSPA4 GDigital broadband packet , all IP , very high throughput100-300Mbps (peak)3.5 MbpsWIMAX,LTE-ABeyond 3GEvolutionary path beyond 3G Mobile class targets 100 Mbps with high mobility Local area class targets 1 Gbps with low mobility

3GPP is currently developing evolutionary/ revolutionary systems beyond 3G 3GPP Long Term Evolution (LTE)

IEEE 802.16-based WiMAX is also evolving towards 4G through 802.16m

MOTIVATION FOR 3G EVOLUTIONCURRENT GENERATION SUPER 3G Voice communicationVoIP, high quality video conferencingSMS, MMSVideo messagingInternet browsingSuper-fast internetDownloadable gamesOnline gaming with mobilityDownloadable videoHigh quality audio & video streamingNo TV serviceBroadcast TV on-demandPeer-to-peer messagingWide-scale distribution of video clipsMobile paymentFile transferMany other innovative ideasLTE TargetsPeak data rate 100 Mbps DL/ 50 Mbps UL within 20 MHz bandwidth. Up to 200 active users in a cell (5 MHz) Less than 5 ms user-plane latencyMobility Optimized for 0 ~ 15 km/h. 15 ~ 120 km/h supported with high performance. Supported up to 350 km/h or even up to 500 km/h. Spectrum flexibility: 1.25 ~ 20 MHzReduced capex/opex via simple architecture

LTE ARCHITECTURE Radio Interfaces Higher Data Throughput Lower Latency More Spectrum Flexibility Improved CAPEX and OPEX IP Core Network Support of non-3GPP Accesses Packet Only Support Improved Security Greater Device Diversity Service Layer More IMS Applications (MBMS, PSS, mobile TV now IMS enabled) Greater session continuity


LTE ARCHITECTUREMain logical nodes in EPC are: PDN Gateway (P-GW) Serving Gateway (S-GW) Mobility Management Entity (MME)EPC also includes other nodes and functions, such: Home Subscriber Server (HSS) Policy Control and Charging Rules Function (PCRF)EPS only provides a bearer path of a certain QoS, control of multimedia applications is provided by the IP Multimedia Subsystem (IMS), which considered outside of EPSE-UTRAN solely contains the evolved base stations, called eNodeB or eNBLTE Enabling TechnologiesTwo main technologies1.Orthogonal Frequency Division Multiplexing (OFDM)

2.Multiple-Input Multiple-Output (MIMO) Antenna technology

11OFDM We have a high rate (hence, large bandwidth) stream of modulation symbols Xk (ex. QAM)Needs to be transmitted on a frequency selective fading channelStream Xk is divided into N low rate parallel sub-streamsBandwidth of each sub-stream is N times narrowerEach sub-stream is carried by one subcarrierReceived must restore each Xk without interference from current or previously transmitted sub-streams

OFDM ConceptTransmitted OFDM Signal

Received OFDM Signal

OFDM Concept

OFDM Concept:OFDM modulation using IFFTGuard time (cyclic prefix) is added to protect against inter-symbol interferenceGuard subcarriers to protect against neighbor channels at both sidesSome subcarriers are used as pilots for channel estimationAfter equalization, receiver performs FFT to retrieve back the stream Xk

OFDM ADVANTAGESOFDM is spectrally efficient IFFT/FFT operation ensures that sub-carriers do not interfere with each other.

OFDM has an inherent robustness against narrowband interference. Narrowband interference will affect at most a couple of sub channels. Information from the affected sub channels can be erased and recovered via the forward error correction (FEC) codes.Equalization is very simple compared to Single-Carrier systems

OFDM ADVANTAGESOFDM has excellent robustness in multi-path environments. Cyclic prefix preserves orthogonality between sub-carriers. Cyclic prefix allows the receiver to capture multi- path energy more efficiently.

Ability to comply with world-wide regulations: Bands and tones can be dynamically turned on/off to comply with changing regulations.

Coexistence with current and future systems: Bands and tones can be dynamically turned on/off for enhanced coexistence with the other devices.

MIMOSignal transmitted from multiple antennas (Multiple In)Signal received by multiple antennas (Multiple Out)

Receiver combines the received signals and optimally combine energy from MxN channelsTwo main types of MIMOTransmit Diversity Spatial Multiplexing

MIMO 2X2, Transmit DiversityTake M=2 and N=2Diversity order 4

MIMO 2x2, Spatial Multiplexing Purpose is to increase data rate (2x2 gives twice data rate) The 4 gains must be known at receiver Spatial multiplexing is a transmission technique in MIMO to transmit independent and separately encoded data signals from each of the multiple transmit antenna .

Spectrum for LTE deploymentsAn operator may introduce LTE in new bands where it is easier to deploy 10 MHz or 20 MHz carriers. e.g. 2.6 GHz band(IMT Extension band) or Digital Dividend spectrum700, 800 MHz Or in re-farmed existing mobile bands e.g. 850, 900, 1700, 1800, 1900, 2100 MHz

Eventually LTE may be deployed in all of these bands and others later

2.6 GHz (for capacity) and 700/800 MHz (wider coverage, improved in-building) is a good combinationLTE offers a choice of carrier bandwidths: 1.4 MHz to 20 MHz; the widest bandwidth will be needed for the highest speeds

Comparative study of 3GPP LTE and Wi-MAX WiMAX (Worldwide Interoperability for Microwave Access), is a wireless communication system that can provide broadband access on a large-scale coverage. It enhances the WLAN (IEEE 802.11) by extending the wireless access to Wide Area Networks and Metropolitan Area Networks.

ParameterWiMAXLTEDuplex methodTDDFDD and TDDBandwidth5 and 10 MHz1.25, 3, 5, 10, 15 & 20 MHzFrame size5 ms10 ms with 10 sub-framesMultiplex Access DLOFDMAOFDMAMultiplex Access ULOFDMASC-FDMAScheduling speedEvery frame (5 ms)Every sub-frame (1 ms)Subcarrier spacing10.9 kHz15 kHzMaximum DL Data rate (SISO)46 Mbps (10 MHz band)50 Mbps (10 MHz band)ModulationQPSK, 16QAM, 64 QAMQPSK, 16QAM, 64 QAMDiversityMIMO up to 2x2TD & SMMIMO up to 4x4TD & SMAdvantages/disadvantages for WiMAX and LTEParameter/CriterionWiMAX(+/-)LTE (+/-)Availability

++ -Migration costs

-++Frequency band options

+ ++Peak data rates

+++Adaptive antenna systems

+++UL performances

+++DL performances

+++Mobility +++Radio access modes(TDD&FDD)

+++QoS provisioning

++++LTE network deployments

April 7, 2010: The number of mobile operators who have committed to deploy LTE advanced mobile broadband systems has more than doubled in the past year. There are now 64 operators committed to LTE network deployments in 31 countries, according to the Global mobile Suppliers Association (GSA) LTE commercial networks -performance Signals Research Group conducted the first ever extensive independent drive test evaluation of a commercial LTE network, assessing the performance of the Telia SoneraLTE networks in Stockholm and Oslo, and reported to GSA:

While still in its infancy, commercial LTE networks in Stockholm and Oslo already outperform many fixed broadband connections, offering average data rates of 16.8Mbps (peak = 50Mbps) and 32.1Mbps (peak = 85Mbps) in 10MHz and 20MHz, respectively. Measured data rates would have been even higher if it had not been for the stringent test methodology, which focused almost entirely on vehicular testing.

Signals Research Group, LLC Signals Ahead, March 2010 LTE: some industry forecastsMaravedis: The number of LTE subscribers worldwide will pass 200 million in 2015 Strategy Analytics: the global LTE handset market will reach 150 million sales units by 2013 ABI Research: by 2013 operators will spend over $8.6 billion on LTE base stations infrastructure IDC: Spending on LTE equipment will exceed WiMAXequipment spend by end 2011, with worldwide LTE infrastructure revenues approaching USD 8 billion by 2014Global mobile Suppliers Association (GSA): up to 22 LTE networks are anticipated to be in commercial service by end 2010, and at least 45 by end 2012 Gartner: long Term Evolution will be the dominant next-generation mobile broadband technology

FUTURE OF LTE LTE-Advanced (LTE-A)LTE-A shall have same or better performance than LTEPeak data rate (peak spectrum efficiency)Downlink: 1 Gbps, Uplink: 500 MbpsPeak spectrum efficiencyDownlink: 30 bps/Hz, Uplink: 15 bps/HzSame requirements as LTE for mobility, coverage, synchronization, spectrum flexibility etc


[1] Erik Dahlman, Stefan Parkvall, Johan Skld, Per Beming, "3G Evolution HSPA and LTE for Mobile Broadband", 2nd edition, Academic Press, 2008, ISBN 978-0-12-374538-5.

[2] K. Fazel and S. Kaiser, Multi-Carrier and Spread Spectrum