3GPP – Long Term Evolution Introduction to LTE LTE Network Architecture LTE Physical Layer SC-FDMA Channel Dependent Scheduling Cognitive Radio for LTE RRM Multiple antenna schemes in LTE LTE-Advanced Conclusion Please like and Comments Mr.Vishal Pawar MITSOT www.mitsot.com www.kmallonline.com http://telecommunicationsdemystified.blogspot.in/ http://marketingmythsdemystified.blogspot.in/

1. 3GPP – Long Term Evolution – A Technical
Study
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Mr. Vishal Pawar
MITSOT

2. Main Topics
• Introduction to LTE
• LTE Network Architecture
• LTE Physical Layer
• SC-FDMA
• Channel Dependent Scheduling
• Cognitive Radio for LTE RRM
• Multiple antenna schemes in LTE
• LTE-Advanced
• Conclusion
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3. Introduction to LTE
• 3GPP Long Term Evolution - the next generation of wireless cellular
technology beyond 3G
• Initiative taken by the 3rd Generation Partnership Project in 2004
• Introduced in Release 8 of 3GPP
• Mobile systems likely to be deployed by 2010
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4. Requirements to be met by LTE
Fast, Efficient, Cheap, Simple
• Peak Data Rates
• Spectrum efficiency
• Reduced Latency
• Mobility
• Spectrum flexibility
• Coverage
• Low complexity and cost
• Interoperability
• Simple packet-oriented E-UTRAN architecture
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5. LTE Network Architecture
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• Simple Architecture
• Flat IP-Based Architecture
• Reduction in latency and cost
• Split between
EPC and E-UTRAN
• Compatibility with 3GPP and
non-3GPP technologies
• eNB-radio interface-related
functions
• MME-manages mobility, UE
identity and security
parameters
• S-GW-node that terminates
the interface towards E-
UTRAN

6. LTE Network Architecture
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7. June 26 2009 7

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9. LTE Frame Structure
• LTE Frame Structure
Type I (FDD)
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10. LTE Frame Structure
Type II (TDD)
June 26 2009 MITSOT_MCNE_LTE 10

11. Single-Carrier Frequency Division Multiple
Access (SC-FDMA)
• Motivation for SC-FDMA
• SC-FDMA utilizes single carrier modulation at the transmitter and
frequency domain equalization at the receiver.
• It has the best of both worlds - the low PAPR of single carrier
systems and the multipath resistance and channel dependent
subcarrier allocation features of OFDM.
• Same complexity and performance as OFDMA
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12. The “SC”-”FDMA” System
DFT-Spread OFDMA – Mapping of spread
symbols , not original symbols to subcarriers!!!
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13. Subcarrier Mapping Schemes
• Localized (LFDMA)
• Distributed (DFDMA)
• Interleaved (IFDMA)
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14. Frequency and Time Domain Representation
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Frequency Time

15. Time domain signals of LFDMA, DFDMA and
IFDMA[20]
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16. PAPR characteristics of an SC-FDMA signal [20]
Comparison of the CCDF of PAPR for LFDMA, DFDMA, IFDMA and
OFDMA
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17. Effect of roll-off factor, alpha on the PAPR[20]
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18. Why does SC-FDMA have a low PAPR?
• OFDMA
• Parallel Transmission
• Multi carrier structure
• Increase in M =>
high PAPR
• SC-FDMA
• Serial Transmission
• Each symbol
represented by a
wide signal – DFT spreads
symbols over all subcarriers
• PAPR not affected by
increase in M
Both occupy the same bandwidth with same symbol durations
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19. SC-FDMA in comparison with OFDMA and DS-
CDMA/FDE
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DS-CDMA/FDE

20. Channel Dependent Scheduling
• Channel is highly frequency
selective
• Resources in deep fade for
one user could be excellent for
another user
• Frequency selectivity of the
channel can be exploited by
using CDS to maximize
throughput
• LFDMA – frequency selective
diversity
• IFDMA – Multi user diversity
(inherently frequency diversity
is obtained)
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21. Cognitive RRM in LTE
• Link adaptation possible as network segments in LTE adapt to the
environmental changes
• System can learn from solutions that were provided in the past
• Faster response, improved performance, intelligent system
• Decisions reg. apt BW,DSA,APA and AM
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22. Cognitive Features to enhance RRM in LTE
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23. Enhanced context acquisition mechanism
architecture for cognitive intra-cell RRM
MITSOT_MCNE_LTE 23

24. Multiple Antenna Schemes in LTE
• In DL : Tx diversity, Rx diversity, Spatial multiplexing (2x2,4x2
configurations – SU-MIMO and MU-MIMO) supported
• In UL : Only 1 Transmitter (antenna selection Tx diversity ), MU-
MIMO possible, Rx diversity with 2 or 4 antennas at eNB supported
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25. LTE Advanced
• LTE doesn’t fulfill the requirements of IMT-Advanced
• 3GPP has also started work on LTE-Advanced, an evolution of LTE,
as a proposal to ITU-R for the development of IMT Advanced.
• LTE Advanced is envisioned to be the “first true 4G technology”.
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26. Requirements of LTE Advanced
• Peak data rates – 1Gbps in DL and 500 Mbps in UL
• Cell edge user data rates twice as high and average user throughput
thrice as high as in LTE
• Peak spectrum efficiency DL: 30 bps/Hz, UL: 15 bps/Hz
• Operate in flexible spectrum allocations up to 100 MHz and support
spectrum aggregation (as BW in DL >>20 MHz)
• An LTE-Advanced capable network must appear as a LTE network
for the LTE UEs
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27. Technological proposals for LTE Advanced
• Larger BW can be used for
high date rates and more
coverage at cell edges
• Advanced repeater structures
• Relaying for adaptive coding
based on link quality
MITSOT_MCNE_LTE 27
Carrier aggregation and
Spectrum aggregation

28. Thank You !
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