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Long term evolution (lte) technology

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This is presented as a part of fulfilment of M.Tech Seminar at IIT Kharagpur.

Text of Long term evolution (lte) technology

  • 1. Long Term Evolution (LTE) Technology Presented byGHANSHYAM MISHRA 11EC63R22 M.Tech, RF & Microwave Engineering IIT KHARAGPUR.

2. OUTLINE:Generation of wireless mobile technologiesTargets for LTELTE architectureLTE enabling technologies:OFDMMIMO antenna technology 3. Continued.Spectrum for LTE deploymentsComparative study of 3GPP LTE and Wi-MAXLTE network performanceLTE- AdvancedReferences 4. GENERATION OF WIRELESSMOBILE COMMUNICATIONGENERATION FEATURES THROUGHPUT TECHNOLOGY1G Analog 14.4 Kbps(peak)AMPS2G Digital , Narrowband, 9.6/14.4 Kbps TDMA(IS-136), GSM, Circuit switched data CDMA (IS-95)2.5 GPacket switched data 171.2 Kbps(peak) GPRS20-40 Kbps3G Digital, broadband 3.1Mbps(peak)CDMA 2000, UMTS and packet data500-700KbpsEDGE3.5 G> 2 Mbps Upto 3.6/7.2/14.4HSPAMbps(peak)1-3 Mbps4G Digital broadband100-300Mbps (peak) WIMAX,LTE-A packet , all IP , very 3.5 Mbps high throughput 5. Beyond 3G Evolutionary path beyond 3G Mobile class targets 100 Mbps with highmobility Local area class targets 1 Gbps with lowmobility 3GPP is currently developing evolutionary/revolutionary systems beyond 3G 3GPP Long Term Evolution (LTE) IEEE 802.16-based WiMAX is also evolvingtowards 4G through 802.16m 6. MOTIVATION FOR 3G EVOLUTIONCURRENT GENERATION SUPER 3GVoice communicationVoIP, high quality video conferencingSMS, MMS Video messagingInternet browsing Super-fast internet Downloadable gamesOnline gaming with mobility Downloadable videoHigh quality audio & video streamingNo TV service Broadcast TV on-demandPeer-to-peer messaging Wide-scale distribution of video clips Mobile payment File transfer Many other innovative ideas 7. LTE Targets Peak data rate 100 Mbps DL/ 50 Mbps UL within 20 MHzbandwidth. Up to 200 active users in a cell (5 MHz) Less than 5 ms user-plane latency Mobility Optimized for 0 ~ 15 km/h. 15 ~ 120 km/h supported with high performance. Supported up to 350 km/h or even up to 500km/h. Spectrum flexibility: 1.25 ~ 20 MHz Reduced capex/opex via simple architecture 8. LTE ARCHITECTURERadio 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 DiversityService Layer More IMS Applications (MBMS, PSS, mobile TV now IMSenabled) Greater session continuity 9. LTE ARCHITECTURE: 10. LTE ARCHITECTURE Main 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 ofmultimedia applications is provided by the IP MultimediaSubsystem (IMS), which considered outside of EPS E-UTRAN solely contains the evolved base stations, called eNodeB or eNB 11. LTE Enabling TechnologiesTwo main technologies1.Orthogonal Frequency Division Multiplexing (OFDM)2.Multiple-Input Multiple-Output (MIMO) Antenna technology 12. OFDM We have a high rate (hence, large bandwidth) stream ofmodulation symbols Xk (ex. QAM) Needs to be transmitted on a frequency selective fadingchannel Stream Xk is divided into N low rate parallel sub-streams Bandwidth of each sub-stream is N times narrower Each sub-stream is carried by one subcarrier Received must restore each Xk without interferencefrom current or previously transmitted sub-streams 13. OFDM Concept Transmitted OFDM Signal Received OFDM Signal 14. OFDM Conceptguard X1 x e j0Serial to ParallelX1 XN-1 TgTb x Add j + Guard e 1 xn1 N 1 2 kn X N-1 xk = 2k/N xn =NX k exp N e jN 1k =0 IFFT 0 1 Unused subcarriers Xk = 0 time N-1 frequencyOFDM SymbolTs =Tb+ Tg 15. OFDM Concept: OFDM modulation using IFFT Guard time (cyclic prefix) is added toprotect against inter-symbol interference Guard subcarriers to protect againstneighbor channels at both sides Some subcarriers are used as pilots forchannel estimation After equalization, receiver performs FFTto retrieve back the stream Xk 16. OFDM ADVANTAGES OFDM is spectrally efficient IFFT/FFT operation ensures that sub-carriers do not interfere with each other. OFDM has an inherent robustness against narrowbandinterference. 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-Carriersystems 17. OFDM ADVANTAGES OFDM has excellent robustness in multi-path environments. Cyclic prefix preserves orthogonality betweensub-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. 18. MIMO Signal transmitted from multiple antennas (Multiple In) Signal received by multiple antennas (Multiple Out) TXRXMN antennas antennas Receiver combines the received signals and optimallycombine energy from MxN channels Two main types of MIMO Transmit Diversity Spatial Multiplexing 19. MIMO 2X2, Transmit Diversity Take M=2 and N=2 Diversity order 4 20. MIMO 2x2, Spatial Multiplexingro = s o g o + s1 g 1r1 = s o g 2 + s1 g 3Purpose is to increase data rate (2x2 gives twice data rate)The 4 gains must be known at receiverSpatial multiplexing is a transmission technique in MIMO to transmitindependent and separately encoded data signals from each of themultiple transmit antenna . 21. Spectrum for LTEdeployments An operator may introduce LTE in new bands where it iseasier to deploy 10 MHz or 20 MHz carriers.e.g. 2.6 GHz band(IMT Extension band) or Digital Dividendspectrum700, 800 MHz Or in re-farmed existing mobilebands e.g. 850, 900, 1700, 1800, 1900, 2100 MHz Eventually LTE may be deployed in all of these bands andothers later 2.6 GHz (for capacity) and 700/800 MHz (wider coverage,improved in-building) is a good combination LTE offers a choice of carrier bandwidths: 1.4 MHz to 20MHz; the widest bandwidth will be needed for the highestspeeds 22. Comparative study of 3GPP LTE and Wi-MAX WiMAX (Worldwide Interoperability forMicrowave Access), is a wireless communication system that canprovide broadband access on a large-scale coverage. It enhances the WLAN (IEEE 802.11) by extendingthe wireless access to Wide Area Networks andMetropolitan Area Networks. 23. ParameterWiMAX LTEDuplex methodTDD FDD and TDDBandwidth5 and 10 MHz1.25, 3, 5, 10, 15 & 20 MHzFrame size 5 ms10 ms with 10 sub-framesMultiplex Access DLOFDMA OFDMAMultiplex Access ULOFDMA SC-FDMAScheduling speed Every frame (5 ms)Every sub-frame (1 ms)Subcarrier spacing 10.9 kHz15 kHzMaximum DL Data rate 46 Mbps (10 MHz band) 50 Mbps (10 MHz band)(SISO)Modulation QPSK, 16QAM, 64 QAM QPSK, 16QAM, 64 QAMDiversityMIMO up to 2x2MIMO up to 4x4 TD & SM TD & SM 24. Advantages/disadvantages for WiMAX and LTEParameter/Criterion WiMAX(+/-) 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++++ 25. 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) 26. LTE commercial networks -performance Signals Research Group conducted the first ever extensiveindependent drive test evaluation of a commercial LTE network,assessing the performance of the Telia SoneraLTE networks inStockholm and Oslo, and reported to GSA:While still in its infancy, commercial LTE networks in Stockholm andOslo already outperform many fixed broadband connections, offeringaverage data rates of 16.8Mbps (peak = 50Mbps) and 32.1Mbps(peak = 85Mbps) in 10MHz and 20MHz, respectively. Measured datarates would have been even higher if it had not been for the stringenttest methodology, which focused almost entirely on vehicular testing.Signals Research Group, LLC Signals Ahead, March 2010 27. LTE: some industry forecasts Maravedis: The number of LTE subscribers worldwide willpass 200 million in 2015 Strategy Analytics: the global LTE handset market willreach 150 million sales units by 2013 ABI Research: by 2013 operators will spend over $8.6billion on LTE base stations infrastructure IDC: Spending on LTE equipment will exceedWiMAXequipment spend by end 2011, with worldwideLTE infrastructure revenues approaching USD 8 billion by2014 Global mobile Suppliers Association (GSA): up to 22 LTEnetworks are anticipated to be in commercial service byend 2010, and at least 45 by end 2012 Gartner: long Term Evolution will be the dominant next-generation mobile broadband technology 28. FUTURE OF LTE LTE-Advanced (LTE-A) LTE-A shall have same or better performancethan LTE Peak data rate (peak spectrum efficiency)Downlink: 1 Gbps, Uplink: 500 Mbps Peak spectrum efficiencyDownlink: 30 bps/Hz, Uplink: 15 bps/Hz Same requirements as LTE for mobility,coverage, synchronization, spectrum flexibilityetc 29. References:[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 Systems: From OFDM and MC-CDMA to LTE and WiMAX, 2nd Edition, John Wiley & Sons, 2008, ISBN 978-0-470-99821-2.[3] H. Ekstrm, A. Furuskr, J. Karlsson, M. Meyer, S. Parkvall, J. Torsner, and M. Wahlqvist, "Technical Solutions for the 3G Long-Term Evolution," IEEE Commun. Mag.