LTE technology introduction
LTE technology introduction| p 2
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Lance Yang( )
Application EngineerApplication & System Support
ROHDE & SCHWARZ Taiwan Ltd. 14F,No.13,Sec. 2,Pei-Tou Road,Taipei, 112,Taiwan, R.O.C.
Phone: +886-2-2893-1088 Ext.321 Fax: +886-2-28917260
email: [email protected]: www.rohde-schwarz.com.twHot Line: 0800-889-669
LTE technology introduction| p 3
Contents l Overview UMTS evolution and 3GPP standardizationl LTE radio transmission schemes
l OFDMl OFDMA / SC-FDMAl Physical channelsl Downlink/uplink
l LTE MIMOl MIMOl Fading
l R&S LTE portfoliol R&S Test Solutions
LTE technology introduction| p 4
UMTS / WCDMA today
140 WCDMA networks launched commercially worldwide*
120 million WCDMA subscribers worldwide as of Mar 2006*
Services: video telephony, video streaming, mobile TV, mobile e-mail,
Challenges:
Continuously improved end-user experience
Improved speed, service attractiveness, service interaction
Long-term 3G competitiveness
*Source: www.umts-forum.org
UMTS = Universal Mobile Telecommunications System
WCDMA = Wideband Code Division Multiple Access
LTE technology introduction| p 5
2009/2010
Today's technology evolution path
GSM/GPRS
UMTS
EDGE, 200 kHzDL: 473 kbpsUL: 473 kbps
E-EDGE, 200 kHzDL: 1.9 MbpsUL: 947 kbps
HSDPA, 5 MHzDL: 14.4 MbpsUL: 2.0 Mbps
HSPA, 5 MHzDL: 14.4 MbpsUL: 5.76 Mbps
HSPA+, Rel. 7DL: 21.0 MbpsUL: 11.5 Mbps
2003/2004 2005/2006 2007/2008 2011/2012
LTE (2x2), Rel. 8, 20 MHzDL: 173 MbpsUL: 58 Mbps
LTE (4x4), 20 MHzDL: 326 MbpsUL: 86 Mbps
HSPA+, Rel. 8DL: 42.0 MbpsUL: 11.5 Mbps
cdma2000
1xEV-DO, Rev. 0 1.25 MHzDL: 2.4 MbpsUL: 153 kbps
1xEV-DO, Rev. A 1.25 MHzDL: 3.1 MbpsUL: 1.8 Mbps
1xEV-DO, Rev. B 5.0 MHzDL: 14.7 MbpsUL: 4.9 Mbps
1xEV-DO, Rev. D (= UMB 4x4) 20 MHzDL: 280 MbpsUL: 68 Mbps
Mobile WiMAXscalable bandwidth1.25 28 MHzup to 15 Mbps
Mobile WiMAX, 802.16e10 MHz DL: 64 Mbps (2x2)UL: 28 Mbps (1x2)
Mobile WiMAX, 802.16m20 MHzDL: >130 Mbps (4x4)UL: 56 Mbps (2x4)
IEEE 802.11a/b/g IEEE 802.11n
1xEV-DO, Rev. C (= UMB 2x2) 20 MHzDL: 140 MbpsUL: 34 Mbps
LTE technology introduction| p 6
UMTS/HSPA voice and data traffic
Voice
Data
Source: Peter Rysavy, 3G Americas
approximately4x-over-year-growth
of data traffic
How the data trafficwill develop in the next years?
LTE technology introduction| p 7
Data traffic growth forecast
Source: Peter Rysavy, 3G Americas
HypothesisToday's (air interface and) core
network might not be able to handle the forecasted data traffic!?
LTE technology introduction| p 8
Why LTE?l Further demand for higher data rates (peak and average) and
a significant decrease of latency,l How this can be achieved?
l Re-use of features like CQI, adaptive modulation and coding, HARQ,l Using higher bandwidths, but flexible and scalable, only possible by
using another transmission scheme,l Further latency reduction with simpler
and flatter network architecture,l Cost efficiency
Affordable roll-out costs (CAPEX1)), low maintenance cost (OPEX2)), l Worldwide network operator commitments for LTE,
1) CAPital Expenditures 2) OPerational EXpenditure
LTE technology introduction| p 9
Ambitious targets with LTE
Significantly increased peak data rate, e.g. 100 Mbps (downlink) and 50 Mbps (uplink),
Significantly improved spectrum efficiency, e.g. 2-4 times compared to 3GPP Release 6,
Improved latency, Radio access network latency (user
plane Network UE) below 30 ms, Significantly reduced control plane
latency, e.g. idle to active
LTE technology introduction| p 10
Dont get confusedLTE = EUTRA(N) = Super3G = 3.9G
l EUTRA(N) = Evolved UMTS Terrestrial Radio Access (Network)l Used within 3GPP for LTE technology / network, like UTRA FDD and
UTRA TDD is used within 3GPP for 3G/UMTS
l Super3Gl Is referring to LTE, like WCDMA is referring to UTRA FDD and TDD
l 3.9Gl Used to indicate that LTE is not 4G, since the requirements for 4G are
set by ITU / IMT-advanced, where 3GPP will approach these requirements with LTE-Advanced
LTE technology introduction| p 11
LTE Key Parameter
Multi-user collaborative MIMO
Wide choice of MIMO configuration options for transmit diversity, spatial multiplexing, and cyclic delay diversity (max. 4 antennas at base station and handset)
Downlink
75 Mbps (20 MHz)
150 Mbps (UE category 4, 2x2 MIMO, 20 MHz)300 Mbps (UE category 5, 4x4 MIMO, 20 MHz)Downlink
OFDMA (Orthogonal Frequency Division Multiple Access)DownlinkSC-FDMA (Single Carrier Frequency Division Multiple Access)
QPSK, 16QAM, 64QAMDownlinkQPSK, 16QAM, 64QAM ( optional for handset)
Uplink
MIMO technology
UplinkPeak Data Rate
UplinkMultiple Access
UplinkModulation Schemes
100 RB75 RB50 RB25 RB15 RB6 RB
20 MHz15 MHz10 MHz5 MHz3 MHz1.4 MHzChannel bandwidth 1 Resource Block (RB)=180 kHz
UMTS FDD bands and UMTS TDD bandsFrequency Range
LTE technology introduction| p 12
LTE UE categories (downlink and uplink)
436672001513763027525
21827072753761507524
21237248753761020483
2123724851024510242
125036810296102961
Maximum number of supported layers for
spatial multiplexing in DL
Total numberof soft
channel bits
Maximum number of bits of a DL-SCH transport block received a TTI
Maximum number of DL-SCH transport block bits received within TTI
UE category
MIMO = Multiple Input Multiple OutputUL-SCH = Uplink Shared ChannelDL-SCH = Downlink Shared ChannelUE = User EquipmentTTI = Transmission Time Interval
Yes753765
No510244
No510243
No254562
No51601
Support 64QAMin UL
Maximum number of UL-SCH transport block bits received within TTI
UE category~300 Mbps
peak DL data rate for 4x4 MIMO
~75 Mbps peakUL data rate
~150 Mbps peak DL data rate
for 2x2 MIMO
LTE technology introduction| p 13
Spectrum flexibility
TransmissionBandwidth [RB]
Transmission Bandwidth Configuration [RB]
Channel Bandwidth [MHz]
Resource block
Channel edge
Channel edge
DC carrier (downlink only)Active Resource Blocks
10075502515 6Number of resource blocks
20151053 1.4Channel bandwidth BWChannel [MHz]
l LTE physical layer /FDD/TDD) supports any bandwidth from 1.4 to 20 MHz,
l Current LTE specification supports a subset of 6 different system bandwidths,
l All UEs must support the maximum bandwidth of 20 MHz,
LTE technology introduction| p 14
Deployment scenarios for LTEl LTE will use same frequency bands as 3G,
l Current 3G frequency blocks, licensed by operators in various countries provide not enough bandwidth, for example in Europe/USA, or a continuous frequency range, for example USA, to roll-out LTE and use the full capacity,
l New frequency ranges will be used to use full capacity of LTE,
l Asia/Europe1) 2.5 to 2.7 GHz,l USA2) 700 MHz Band,l Inter-working between WCDMA/HSPA,
CDMA2000 1xRTT/1xEV-DO and GSM/EDGE is considered and currently specified,
2.6 GHz antennas used for field trial test on LTE in Nuremberg, GERMANY
1) Auction in Norway, Sweden happened, Austria, Hong Kong, Netherlands Q1/2009, Germany, UK probably Q2/2009, Spain, Portugal probably Q4/2009, Italy, France probably Q1/2010
2) auction happened, spectrum available in February 2009
LTE technology introduction| p 15
What is OFDM basically?
5 MHz
Single Carrier Transmission (e.g. WCDMA)
e.g. 5 MHz
(Orthogonal )Frequency Division
Multiplexing ((O)FDM)
Typically several 100 sub-carriers with spacing of x kHz
l Orthogonal Frequency Division Multiplex (OFDM) is a multi-carrier transmission technique, which divides the available spectrum into many subcarriers, each one being modulated by a low data rate stream,
LTE technology introduction| p 16
OFDM SummaryAdvantagesOFDM SummaryAdvantages and disadvantages
l High spectral efficiency due to efficient use of available bandwidth,l Scalable bandwidths and data rates,
l Robust against narrow-band co-channel interference, Intersymbol Interference (ISI) and fading caused by multipath propagation,
l Can easily adapt to severe channel conditions without complex equalizationl 1-tap equalization in frequency
domain,l Low sensitivity to time
synchronization errors,
l Very sensitive to frequency synchronization,l Phase noise, frequency and clock offset,
l Sensitive to Doppler shift,l Guard interval required to minimize
effects of ISI and ICI,l High peak-to-average power ratio
(PAPR), due to the independent phases of the sub-carriers mean that they will often combine constructively,l High-resolution DAC and ADC required,l Requiring linear transmitter circuitry, which
suffers from poor power efficiency, Any non-linearity will cause intermodulation
distortion raising phase noise, causing Inter-Carrier Interference (ICI) and out-of-band spurious radiation.
LTE technology introduction| p 17
LTE Physical Layer ConceptsOFDMA in the Downlink
LTE technology introduction| p 18
Difference between OFDM and OFDMA
l OFDM allocates user just in t
