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Further LTE Enhancements toward Future Radio Access
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Further LTE Enhancements toward Future Radio Access Presentation Transcript

  • 1. Further LTE Enhancements toward Future Radio Access Takehiro Nakamura NTT DOCOMO, Inc.NTT DOCOMO, INC., Copyright 2012, All rights reserved. 1
  • 2. LTE Release 10/11 (LTE-Advanced) StandardizationNTT DOCOMO, INC., Copyright 2012, All rights reserved. 2
  • 3. 3GPP仕様のリリース 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 GSM/GPRS/EDGE enhancementsRelease 99 W-CDMA Release 4 1.28Mcps TDD Release 5 HSDPA Release 6 HSUPA, MBMS Release 7 HSPA+ (MIMO, HOM etc.) ITU-R M.1457 Release 8 LTE IMT-2000 Recommendation Minor LTE Release 9 enhancements Approved at ITU-R RA ITU-R M.2012 in Jan. 2012 Release 10 LTE-Advanced IMT-Advanced Release 11 Recommendation 3GPP TSG-RAN Workshop on Release 12 onward to be held on June 11-12, 2012 NTT DOCOMO, INC., Copyright 2012, All rights reserved. 3
  • 4. Key Requirements for LTE-Advanced LTE-Advanced (LTE Release 10) • LTE-Advanced shall be deployed as an LTE Release 9 evolution of LTE Release 8 and on new bands. LTE Release 8 • LTE-Advanced shall be backwards compatible with LTE Release 8 LTE-Advanced contains all features  Smooth and flexible system migration of LTE Rel-8&9 and additional features for further evolution from Rel-8 LTE to LTE-Advanced LTE-Advanced evolved from LTE Rel-8 LTE Rel-8 cell LTE-Advanced cell LTE Rel-8 terminal LTE-Advanced terminal LTE Rel-8 terminal LTE-Advanced terminal An LTE-Advanced terminal An LTE Rel-8 terminal can can work in an LTE Rel-8 cell work in an LTE-Advanced cell LTE-Advanced backward compatibility with LTE Rel-8NTT DOCOMO, INC., Copyright 2012, All rights reserved.March 4, 2011 4
  • 5. Key Features in LTE Release 10&11 100 MHz  Support of Wider Bandwidth(Carrier Aggregation) Rel-10&11 • Use of multiple component carriers(CC) to extend bandwidth up to 100 MHz • Common physical layer parameters between component carrier and LTE Rel-8 carrier f  Improvement of peak data rate, backward compatibility with LTE Rel-8 CC  Advanced MIMO techniques Rel-10 • Extension to up to 8-layer transmission in downlink • Introduction of single-user MIMO up to 4-layer transmission in uplink • Enhancements of multi-user MIMO  Improvement of peak data rate and capacity  Heterogeneous network and eICIC(enhanced Inter-Cell Interference Coordination) Rel-10&11 • Interference coordination for overlaid deployment of cells with different Tx power  Improvement of cell-edge throughput and coverage  Relay Rel-10 • Type 1 relay supports radio backhaul and creates a separate cell and appear as Rel-8 LTE eNB to Rel-8 LTE UEs  Improvement of coverage and flexibility of service area extension  Coordinated Multi-Point transmission and reception (CoMP) Rel-11 • Support of multi-cell transmission and reception  Improvement of cell-edge throughput and coverage  Interference rejection combining (IRC) UE receiver Rel-11 • Improved minimum performance requirements for E-UTRA  Improvement of cell-edge throughputNTT DOCOMO, INC., Copyright 2012, All rights reserved. 5
  • 6. Future Radio Access (LTE Release 12 and Beyond)NTT DOCOMO, INC., Copyright 2012, All rights reserved. 6
  • 7. Growth of Packet Traffic in DOCOMO • Various services, especially video services, and high-speed mobile access increased amount of mobile data traffic – Approx. 1.6 times per year (2004 – 2009) – Approx. 2 times per year (2010-2011) • Further traffic growth is projected due to dramatic increase in Smartphone salesNTT DOCOMO, INC., Copyright 2012, All rights reserved. 7
  • 8. Forecast of Mobile Data Traffic Growth Cisco VNI Mobile: Mobile video has the highest growth rate of any application category UMTS Forum:By 2015, the mobile data trafficfootprint of a single subscribercould be 450 times what it was10 years earlier in 2005. Consensus in the industry is that there will be substantial growthNTT DOCOMO,demand for mobile data traffic over the next 5 – 10 years in INC., Copyright 2012, All rights reserved. 8
  • 9. Approach for Capacity Enhancements We need set of radio access technologies to satisfy future requirements of 500-1000x capacity Required capacity (bps/km2 = bps/Hz/cell x Hz x cell/km2) Spectrum efficiency Traffic offloading (alternative means for communication) TRx TRx TRx TRx TRx TRx TRx WiFi offload, D2D, etc. TRx Non-orthogonal multiple access Controller Network density Massive MIMO, Current Home/office Dense urban Advanced receiver capacity Shopping mall Study for new interference scenarios Cellular network assists Multiple access technologies local area radio access with Tx-Rx cooperative Spectrum extension interference cancellation Existing cellular bands Higher/wider frequency bands New cellular concept for cost/energy- efficient dense deployments Very wide Super wide Frequency Hybrid access using coverage and capacity spectrum bandsNTT DOCOMO, INC., Copyright 2012, All rights reserved. 9
  • 10. Other Requirements (1) Requirements mainly from user perspective Gbps-order • Higher data rate and user- experienced throughput experienced throughput 100 Mbps 1 Gbps wide area wide area – Data rate competitive to that of Mobility Mobility 1 Gbps 10 Gbps future wired networks IMT-Advanced peak IMT-Advanced peak van diagram van diagram • Gbps-order experienced Data rate Data rate throughput – Low latency for improving user 10x improvement in the next decade experience  More spectra utilized efficiently • Fairness of user throughput – In a cell • Improve cell-edge throughput – Among cells • Urban to rural • Digital divide – Among users • Lower system impact from few Source: Artist4G (FP7 ICT), Jan. 2010 heavy usersNTT DOCOMO, INC., Copyright 2012, All rights reserved. 10
  • 11. Other Requirements (2) Requirements mainly from operator perspective • Flexible, easy, and cost-efficient Non-contiguous spectrum allocation operation over wide range of frequencies – For diverse spectrum allocation • Efficient utilization of Frequency higher/wider frequency bands Different duplex schemes may be applied – For diverse environments and network nodes/devices with different types of backhauling • RRE, Femto, relay, etc. – For diverse types of services, user devices, and communication Macrocells RRE Femto methodologies • MTC, thin client, etc. • Energy saving (Green) – Reduction in joule per bit • System robustness against emergencies Robustness to emergencies – Earthquake, Tsunami, etc.NTT DOCOMO, INC., Copyright 2012, All rights reserved. 11
  • 12. Possible Standardization Scenario • Standardization scenario towards 2020 – Mid-to-long term evolution introducing new technologies to achieve required capacity gain based on 3GPP LTE radio interface – The following two types of evolutions to be considered Backward-compatible evolutions Legacy Complementary Rel. 8 Rel. 10 Rel. 11 Rel. 1X carrier type evolutions Additional Rel. 11 Rel. 1X carrier type New carrier type or new radio inter face Rel. 1X New RAT? • Backward-compatible evolutions – Evolutions backward compatible to legacy UEs sharing the same spectrum bands – New technologies to be introduced, e.g., for further improving spectrum efficiency • Most of new radio access technologies can be introduced in future LTE releases using LTE (OFDM/SC-FDMA) based signal waveform • Complementary evolutions – Introduction of new carrier type that is complementary to legacy carrier type(s) with backward-compatible evolutions – Evolutions focusing on new frequency spectrum bands and/or specific scenarios such as enhanced local area radio accessNTT DOCOMO, INC., Copyright 2012, All rights reserved. 12
  • 13. Technologies Related to Efficient Spectrum Extension and Utilization Capacity Spectrum extensionNTT DOCOMO, INC., Copyright 2012, All rights reserved. 13
  • 14. Wider Bandwidth • Super-wideband to achieve “Gbps” as typical data rate  At least more than 200 MHz will be desirable (maybe up to 1 GHz) Examples to achieve 1-Gbps data rate Bandwidth Spectrum efficiency 100 MHz 10 bps/Hz (4x4 MIMO) LTE-A 200 MHz 5 bps/Hz (2x2 MIMO) FRA  Gbps to be achieved with lower 300 MHz 3.3 bps/Hz (~64QAM) spectrum efficiency, e.g., without MIMO 600 MHz 1.7 bps/Hz (~16QAM) (More than 10-Gbps can be achieved 1000 MHz 1 bps/Hz (~QPSK) by MIMO technology) • Utilization of much higher frequencies – Maybe possible to find contiguous wideband spectrum in higher frequency How to use in Existing cellular bands Higher frequency bands cellular systems ? Very wide Super wide (e.g. > 3.5GHz) (e.g. > 10GHz) FrequencyNTT DOCOMO, INC., Copyright 2012, All rights reserved. 14
  • 15. Efficient Spectrum Utilization • Hybrid radio access using lower & higher frequency bands – Basic coverage/mobility supported in lower frequency bands, e.g., existing cellular bands • Current Service Quality in terms of Connectivity/ Mobility can be maintained • Support control signaling for efficient small-cell discovery – High speed data transmission supported in higher frequency bands • Large bandwidth • Mainly for smaller or denser cell deployments Existing cellular bands Higher frequency bands (high power density for coverage) (wider bandwidth for high data rate) Very wide Super wide (e.g. > 3.5GHz) (e.g. > 10GHz) Frequency Hybrid radio access Macro-cellular deployments Various local area scenarios supporting full coverage area with low-power nodes/devicesNTT DOCOMO, INC., Copyright 2012, All rights reserved. 15
  • 16. Technologies for Efficient Support of Denser Network Deployments CapacityNTT DOCOMO, INC., Copyright 2012, All rights reserved. 16
  • 17. Requirements for Denser Network Deployments • Capacity per NW cost (bps/cost) = Capacity per unit area / NW cost per unit area (bps/km2 (= bps/cell x cell/km2)) (cost/km2) Spectrum efficiency x bandwidth - Low cost NW node & backhaul deployments km - Easy cell planning & maintenance - NW energy saving km • Efficient small cell identification & mobility – UE battery saving Macro cell • Can be optimized to low mobility – Support for non-uniform deployments • Dense cells for high traffic area • Less efforts on cell planning Small cellNTT DOCOMO, INC., Copyright 2012, All rights reserved. 17
  • 18. Deployment Scenarios • Two deployment scenarios are identified for small-cell deployments (increasing network density): – Scenario 1 (Mixed deployment scenario): • Small cell and Macro cell co-exist on a single carrier. – Scenario 2 (Small-cell dedicated carrier scenario): • Small cell utilizes a dedicated carrier, where no Macro cell exists.  Secenario 1 was studied in Rel-11. We assume Scenario 2 getting more and more important in Rel-12 onward Scenario 1: Mixed deployment scenario Scenario 2: Small-cell dedicated carrier scenario F1 F0 F2NTT DOCOMO, INC., Copyright 2012, All rights reserved. 18
  • 19. RRH CA Deployments Macro cell link Macro cell 2 GHz (Example) RRH RRH RRH 3.5 GHz (Example) RRH RRH link  Macro cell link can maintain good connectivity and mobility  RRH link can provide high throughput due to frequency reuse using small RRH cells  Additional carrier type for RRH link would provide more flexible and cost/energy-efficient operationsNTT DOCOMO, INC., Copyright 2012, All rights reserved. 19
  • 20. Technologies for Further Enhancing Spectrum Efficiency Spectrum efficiency CapacityNTT DOCOMO, INC., Copyright 2012, All rights reserved. 20
  • 21. Different Requirements Between WA and LA Spectra • Different requirements for radio access between Wide Area (WA) and Local Area (LA) spectra in HetNet deployments – But, commonality between WA and LA to be considered within a framework of LTE-based radio interface Wide Area spectrum Local Area spectrum Spectrum efficiency Very important Important (limited BW) (may not be critical if large BW available) Mobility Medium-to-High Low Coverage Essential Not critical (but wider is better) DL/UL radio link Asymmetric More symmetric Traffic load More uniform More fluctuated (many users & cell planning) (less users & non-uniform deployments) Macro-cellular deployments Various local area scenarios supporting full coverage area with low-power nodes/devicesNTT DOCOMO, INC., Copyright 2012, All rights reserved. 21
  • 22. FDD/TDD in Local Area • FDD is advantageous over TDD in wide area – No need for synchronization among cells/operators • The adjacent channel interference is much lower than in TDD – Wider coverage and lower latency owing to continuous transmission • DL/UL channels are always "open“ • TDD might be more applicable in local area & in higher frequency bands – Requirements on synchronization among operators can be relaxed in local area – Potential benefits in spectrum sharing between DL/UL – Dynamic TDD • Traffic is more bursty (unbalanced DL/UL) in local area • Interference management of DL/UL transmissions is required among multi-points – Possibly facilitate worldwide harmonized spectrum allocation • Flexible spectrum allocation • No need for guard band (No need for duplexer) Static DL/UL User #2 User #2 Dynamic DL/UL allocation User #1 UL DL User #1 UL allocation UL DL DL UL DL DL UL DL User #4 Enhanced DL User #4 User #3 efficiency User #3NTT DOCOMO, INC., Copyright 2012, All rights reserved. 22
  • 23. Concept of Hybrid Radio Access • Hybrid radio access – Adaptation of radio access schemes according to environments, spectrum bands, types of traffic, etc. • Required high commonality in radio interface among radio access schemes Adaptation for radio access schemes Wide area/lower frequency Local area/higher frequency • Example of hybrid access schemes – Hybrid FDD and TDD according to cell environments – Hybrid non-orthogonal and orthogonal multiple access schemes according to, e.g., path loss variation among users Path loss variation Non-orthogonal Large Small Orthogonal (Local area) freq/time (Wide area) freq/time – Hybrid multi-carrier and single-carrier transmission schemes according to, e.g., required coverage or cell environments Wide area Resource DFT (SC) mapping Tx data & Power IFFT Transmission Local area S/P (MC)NTT DOCOMO, INC., Copyright 2012, All rights reserved. control 23
  • 24. Conclusion • LTE Release 10 and 11 – LTE Release 10 was developped and approved in ITU-R M.2012 as LTE-Advanced – LTE Release 11 is under development to enhance LTE Release 10 technologies • Future Radio Access (LTE Release 12 and beyond) – 3GPP will hold a Workshop on Release 12 onward to identify requirements and potential technologies for Future Radio Access – Variety of requirements including reduced cost and further capacity enhancements needed by traffic explosion – Two evolution scenarios, backward compatible evolution and complementary evolution, to satisfy both of backward compatibility and sufficient gain – Key techniques to meet requirements • Efficient utilization of higher and wider spectrum bands • New small-cell dedicated carrier for efficient and simple NW densification • Hybrid Radio Access for wide area and local area enhancementsNTT DOCOMO, INC., Copyright 2012, All rights reserved. 24
  • 25. NTT DOCOMO, INC., Copyright 2012, All rights reserved. 25