LTE B4G Evolution


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LTE B4G Evolution

  1. 1. Younsun Kim ( DMC R&D Center, STE Team
  2. 2. • Challenges • Rel-12/13 Technologies -Small Cell Enhancements -TDD Interference Management and Traffic Adaptation (eIMTA) -Enhanced COMP (eCoMP) -Full Dimension MIMO (FD-MIMO) -Network Assisted Interference Cancellation and Suppression (NAICS) -Device to Device Communication (D2D) -Coordination with WiFi -User Plane Congestion Management (UPCON) • NGMN Activities • Concluding Remarks
  3. 3. Challenges
  4. 4. Users experience network congestions CAPEX Increase OPEX Increase QoE Decrease1 COST Increase2 User QoE decrease and Cost increase due to Mobile Traffic Growth Mobile Traffic Growth vs. Operator Revenues saturation Increase Revenue Decrease Cost Revenue Decoupling Revenue decoupling3
  5. 5. Increasing Mobile Data Volume1 Increasing Mobile Data Diversity2
  6. 6. LTE Release 12/13 Technologies
  7. 7. 1H 2H 1H 2H 1H 2H 1H 2H 1H 2H 1H 2H 2011 2012 2013 2014 2015 2016 Release 11 (LTE-A) Release 12 (Beyond 4G) Release 13 (Beyond 4G) 2011.09 Stage 1 Stage 3 ASN.1 Freeze 2011.03 Stage 1 Rel-12 and onwards WS 2012.6 2014.06 Stage 3 ASN.1 Freeze 2014.09 2012.09 2013.03 Release 14 (5G) 1H 2H 2017 Projected completion of R13 Projected completion of R14
  8. 8.  Small cell enhancement  CoMP enhancement  FD-MIMO  Diverse traffic support  20MHz, OFDMA/SC-FDMA  DL 4x4 MIMO  SON, HeNB  SAE Rel-8/9 LTE Rel-10/11 LTE-Advanced (4G) Rel-12/13 LTE-Future (Beyond-4G) 2009 CPRI LTE Infrastructure IP FD-MIMO eNB High order MU-MIMO transmission to more than 10 UEs 2012 2015 UE TP0 (Cell ID=X) TP2 (Cell ID=X) TP1 (Cell ID=X) TP4 (Cell ID=X) TP3 (Cell ID=X) Desired Signal Interference  Carrier aggregation  DL/UL COMP  UL 4x4 MIMO  HetNet
  9. 9.  Small Cell Enhancement becomes important because … -Network capacity and user throughput boosting utilizing small cells -3.5 GHz band is ideal for small cell deployments (large available BW)  Issues in Small Cell -Overhead due to frequent cell change -Inter-frequency mobility -Power consumption due to cell discovery -Need to consider non-ideal backhaul -Support of 256QAM Existing cellular band (coverage, mobility) New frequency band (> 3GHz) (high data rate, traffic offloading) E-UTRA Band UL DL Duplex Mode 22 3410 – 3490 MHz 3510 – 3590 MHz FDD 42 3400 – 3600 MHz 3400 – 3600 MHz TDD 43 3600 – 3800 MHz 3600 – 3800 MHz TDD 3GPP: Operating band 22 (FDD) & 42 / 43(TDD)
  10. 10. Improved interaction/mobility between Macro and Pico  Non-CA: Improved Macro-Pico Layer mobility -Improved/Relaxed Pico cell detection -Improved Pico->Macro Handover Failure (HOF) rate -Improved Pico->Macro Radio Link Failure (RLF) handling  Carrier Aggregation (CA) -CA based on Inter-eNB Carrier Aggregation Alt1: Data splitting in RAN Alt2: Data splitting in Core Network Final solution “package” might be combination of different solutions… f1 f2 Data rate Macro eNB Pico eNB MME S-GW Big pipe from small cell Control Data Anchor to macro
  11. 11.  Carrier Aggregation in LTE-A (Release 10 and 11) is important because … - Allows access to bandwidth of up to 100MHz (20MHz x 5) - Allows frequency resources on different bands to be used together (800MHz + 1.5GHz) - Allows flexible load balancing between frequency bands  Inter-eNB Carrier Aggregation in Release 12 - Can be used to realize multi-flow (data from multiple eNBs) from geographically separated eNBs - Macro-cell layer and pico-cell layer can be used for dedicated purposes → E.g., Macro-cell layer on f1 for mobility robustness, pico cell layer on f2 for data fat pipe  Two architecture alternatives  CN split:  RAN split: DataBearer2 DataBearer1 UE MME S-GW Serving ENB Drift ENB UE MME S-GW Serving ENB Drift ENB PDCCH/PUCCH UE MME S-GW Serving ENB Drift ENB UE MME S-GW Serving ENB Drift ENB DataBearer2 DataBearer1 PDCCH/PUCCH
  12. 12. Scenario 1: Co-channel scenario  small cell cluster 1 small cell cluster 2 F1  Scenario 2A: Dual-channel outdoor scenario small cell cluster 1 small cell cluster 2 F1 F2 macro cell small cell cluster 1 small cell cluster 2 F1 F2 macro cell Scenario 2B: Dual-channel outdoor scenario  small cell cluster 1 small cell cluster 2 F2  Scenario 3: Indoor scenario
  13. 13.  Characteristics of TDD systems -Ratio of uplink and downlink resources can be configured (LTE provides 7 configurations) -However, dynamic UL-DL configuration change is currently not feasible  Objective of eIMTA -Provide mechanisms that allow dynamic switching between uplink and downlink TDD resources D S U U U D S U U U D S U D S UD D D D dynamically over time, also between nodes Hotspot area 1: change UL resource to DL resource
  14. 14.  Mechanism for traffic adaptation for reconfiguration -Flexible subframes: Subframes which can switch between uplink and downlink  Interference scenarios -UL-DL & DL-UL interference in flexible subframe between cluster or cell -DL-DL or UL-UL interference in other subframe DL SP UL DL/UL DL/UL DL DL/SP DL/UL DL/UL DL/UL TDD UL/DL configuration Flexible subframe Flexible subframe Heavy UL traffic Heavy DL traffic TDD configuration 5 in cell BTDD configuration 0 in cell A UL-DL interference
  15. 15.  Motivation of LTE FDD – TDD CA -Efficient spectrum utilization of available frequency bands -Increased capacity and higher user throughput  LTE FDD – TDD CA deployment scenarios -Existing Rel-10/11 CA deployment scenarios (intra-eNB CA) -Small cell scenarios where eNBs are not colocated (inter-eNB CA)  Independent duplex mode between macro and small cell  LTE FDD – TDD CA configurations -Either FDD or TDD cell as Pcell -Aggregation of two and more carriers TDD FDD FDD (TDD) Small cellSmall cell TDD (FDD)
  16. 16.  CoMP provides mechanism for network interference coordination  Improves coverage of high data rates  Improves cell-edge and system average throughput  Specification support in Release 11  Definition of CSI process which consists of a channel measurement resource (CMR) and an interference measurement resource (IMR)  Support for multiple CSI processes (up to 4)  Support for quasi-colocation Multiple RRHs sharing a common Cell_ID • No need for handover between RRHs • Flexible cell virtualization possible ‘CoMP Scn4' SystemTraditional Multi-Cell System Each RRH has its own Cell_ID • Handover required between RRHs
  17. 17.  Although CoMP in Release 11 provides means for efficient network coordination  All standardization effort was concentrated on the air interface (PHY/RRC between UE and eNB)  No explicit standardization  eCoMP in Release 12  Should provide additional supports for enhanced network coordination Release 11 CoMP Release 12 eCoMP • No explicit support for efficient joint transmission operation • Relied on heavy CSI feedback overhead in the uplink • Focused on the air-interface aspect only  Relies on proprietary interface between eNBs and coordination entity  Not designed for robust performance in networks with non-ideal backhaul • Should provide means for efficient joint transmission operation • Should provide means for CSI feedback compression to reduce uplink overhead • Should support network interface for inter-eNB coordination  Support coordination among eNBs of different vendors  Design to provide robust performance even in networks with non-ideal backhaul
  18. 18.  Coherent JT showed significant performance gain  30~40% cell-edge gain for 2x2 MU-JT [TR 36.819]  No explicit specification support for coherent JT in Rel-11  Possible enhancement for JT  Inter-transmission point phase information for coherent joint transmission  Aggregate CQI for joint transmission RRH1 precoding: 1 0.7+0.7j RRH2 precoding: 1 -0.7-0.7j RRH1 RRH2 Inter-TP phase/ Aggregated CQI  CSI Compression and CSI Multiplexing  R11 CoMP relies on multiple CSI processes for CoMP (linear increase in UL overhead)  Probability of CSI collision and CSI dropping could be extremely high for multiple CSI processes  CSI-RSRP (CSI-RS Reference Signal Received Power)  Ease network management of CSI-RS resources for CoMP CSI feedbacks, especially for CoMP Scn 4  Provide CoMP gains even for UEs with one CSI process capability
  19. 19.  One key area of eCoMP will be the specification support of inter-eNB coordination  eCoMP work item likely to be approved in next RAN plenary (June, 2013)  RAN1: Evaluate system performance  RAN3: Standardization of new interface that supports inter-eNB coordination Resource Coordinator Resource allocationMultiple sets of downlink channel status info  Some expected benefits of R12 eCoMP  Provides robust coordination performance even on non-ideal backhauls  Allows coordination between eNBs of different vendors
  20. 20. Solution for capacity boosting Full Dimension MIMO with 2D AAS (Active Antenna System) 1) MU-MIMO with 10s of UEs 2) 2D AAS array & 100 antennas 3) 3D-SCM channel Performance and cost Perf “4.5x“ commercial LTE Cost “1.x“ commercial LTE Now # TX antennas for LTE commercial BS “2” Proposal # TX antennas for FD-MIMO “64” Samsung leads discussion on FD-MIMO in 3GPP CPRI LTE Infrastructure IP FD-MIMO eNB High order MU-MIMO transmission to more than 10 UEs
  21. 21. FD-MIMO antenna panel form factor is well within practical range λ=12cm @ 2.5GHz Example 1: 8Hx8V array with “uniform” elements Full digital beamforming across 64 elements λ/2 λ/2 0.5m 0.5m Example 2: 8Hx4V array with “rectangular” elements Each element is 4 antennas with analog beamforming λ/2 2λ 0.5m 1m
  22. 22.  Associate elevation angles to paths generated by SCM  Correlate elevation statistics with other large-scale fading parameters  Reuse the mechanism and procedure in SCM One Path = 20 subpath (Same power, offset of phase, angle) path Each path - Delay, AoA, AoD 2 array antenna UE antenna Cluster horizontal vertical x y z
  23. 23. • User per sector: K=10 • Ant. spacing: V-2.0l,H-0.5l • Scheduler: Full UE scheduling(A1) • Horizontal 3dB beamwidth: 90° • Vertical 3dB beamwidth: 90° • Peak antenna gain: 6.4dBi 14.139 [1,64] [1,32] [1,16] [1,8] 0.798 [16,1] [64,1] 9.416 5.617 0.461 3.014 [32,1] 0.2280.108 [8,1] [2,32] [4,4] [5% user throughput (bps/Hz)] Cellaveragethroughput(bps/Hz) Assumptions Similar antenna gain between vertical and horizontal [NT-V, 1] vs [1, NT-H] if NT-V=NT-H 0.9x (Cell throughput) 0.97x (User throughput) [1,8]  [8,8] 8X (# of total antenna) 4.2X (Cell throughput) 6X (User throughput) Summary [8,8] Legend [4,8] 12.754 0.651 NT =64 NT =32 NT =16 NT = 8
  24. 24.  Objective of NAICS (Network Assisted Interference Cancellation and Suppression) study item:  Evaluate potential gains of advanced UE receivers with network assistance  Study necessary specification support  Advanced UE receivers under consideration  Linear MMSE IRC  Successive interference cancellation  Maximum likelihood detector Cell A Cell B PDSCHA UE A UE B PDSCHB PDSCHA UE A UE B PDSCHB NAICS for inter-cell interference NAICS for intra-cell interference • Cell A and Cell B exchange information on PDSCHA and PDSCHB • Necessary information to perform NAICS is forwarded to each UE • Information on PDSCHA and PDSCHB are available in the same eNB location (no need for information exchange) • Necessary information to perform NAICS is forwarded to each UE
  25. 25.  Side information on dominant interferers  Ex: MCS level, RB allocation, DMRS port(s)  Might need to define new DCI format for indication of this side information  Support for more accurate downlink interference measurement  For the purpose of interference suppression or cancellation  In any case, specification support should target  Wide range of UE application  Robust receiver performance  Reasonable control overhead Cell A Cell B PDSCHA UE A UE B PDSCHB Sideinformation on PDSCHB Sideinformation on PDSCHB Side information on PDSCHB is provided on PDCCHA
  26. 26. Device to Device Communications for new service and new market  Proximity based commercial service  Advertisement  Social Network Service (SNS)  Gaming  Public safety using LTE network (even when network is not working) advertisement Where are you? Just next to you.. Me too.. SNS I win OTL Gaming
  27. 27. 0 Scenario 2: Targeted AdvertisingScenario 1: Social Networking
  28. 28. Component techniques RAN1 Time plan Peer Discovery - UE discovers other UEs proximate to itself - For both commercial service and public safety Direct communication - UE transmits data to other UE with or without network assistance - Supported at least for public safety Out of network coverage - Both peer discovery and direct communication should be supported for public safety RAN1 #72 RAN1 #72b RAN1 #73 RAN1 #74 RAN1 #74b RAN1 #75 RAN1 #76 Evaluation methodology Design of peer discovery and direct communication Evaluation and performance verification End of D2D study item: March 2014
  29. 29.  Priority between commercial use case and public safety use case  Synchronization between cells  D2D Band: UL band vs DL band  Transmission scheme: OFDM vs SC-FDMA  Peer Discovery: what to transmit and how to transmit  Direct communication: detailed design and procedure  Multiplexing of cellular resource and D2D resource
  30. 30.  Smarter opportunistic usage of WiFi to improve user experience  LTE/HSPA small cell and WiFi access points may or may not be co-sited Hotspot WLAN deployment with little integration and non-seamless offload WLAN deployment as extension of LTE network to meet increasing data demands, seamless offload
  31. 31. Example: – All traffic uses the default bearer and RAN node is overloaded – UE1’s preference is app1 and UE2’s preference is app2 – eNB notifies the overload to PGW – PGW selects the flow for each UE and gives event notification to PCRF and AF – The AF performs rate control on non-preferred traffic. PCRF HSSMME PGW eNB SGW PDN Traffic Control by application Select UE/IP flows to be Controlled App AF App AF congestion App App Congestion status Congestion status Congestion status SD QoE Improvement QoE improvement by considering network status at application/service  Selective application/service/user traffic management  Specification impact  Definition of new messages for informing congestion status to the core network  Mechanism to provide user/application-specific information to the core network/eNB
  32. 32. NGMN Activities
  33. 33.  NGMN Operating Committee approved four projects (Nov, 2012)  Project 1 “RAN Evolution” includes four Work Streams  Cloud-RAN  CoMP (Coordinated Multi-Point Tx/Rx)  Front/Backhaul Evolution  Multi-RAN (2G/3G/4G) Cooperation & Architecture Information Exchange Architecture Evolution&Cloud Operational Excellence & Efficiency E2EQuality of Service &User Experience Implementation Aspects Project 1 :RAN Evolution Lead : CMCC Duration : Feb,2013 ~ Feb,2014 Project 2 :Small Cells Lead : Telecom Italia Duration : Feb,2013 ~ Feb,2014 Project 3 :NGCOR* Phase 2 Lead : DTAG Duration : June,2012 ~ June,2013 Project 4 :Mobile Contents Delivery Optimization Lead : DTAG Duration : June,2012 ~ June,2013 Scope of NGMN Beyond 2012 * NGCOR: Next Generation Converged Operations
  34. 34.  CoMP is one of the work streams in Project 1 “RAN Evolution”  Leader: CMCC  Co-Leaders: Samsung and ALU  Gather operators’ views on future deployment of CoMP  Considerations on network architectures  Deployment scenarios  Performance targets  Outcome of the NGMN activities will be provided to 3GPP  Guidance for future standardization activities  Leading to a cost-effective network evolution Project approval ‘13.02 ‘13.05 Feedback from practical deployment ‘13.07 Analyze CoMP schemes over ideal backhaul ‘13.08 Analyze CoMP schemes over non-ideal backhaul CoMP White Paper ‘14.02
  35. 35.  Mobile Contents Delivery Optimization Project in NGMN -Deliverables: White papers for Use Scenarios, Requirements, Potential Solutions and STD impact -SDO Coordination: Liaison letter to the related SDO e.g. 3GPP, MEPG, IETF -Timeline: 2013.02 ~ 2014.02 (Phase 1)  Some Solutions 1) Access Cache: Placing the transparent cache node nearby RAN node Recommendations 2) Media Processing Function: Introducing Media Processing Function in Mobile Operator Network Benefit 1. Save the backhaul cost: for the duplicate contents 2. Increase the throughput by proxy’ing TCP connection (due to the short RTT of TCP connection) Benefit 1. Operator-controlled Media Adaptation with policy interface 2. Dynamic inline frame dropping using MPEG Media Transport
  36. 36. Concluding Remarks
  37. 37.  Main challenges for future mobile systems - Increasing mobile data volume - Increasing mobile data diversity  LTE specification support to overcome challenges - Increasing mobile data volume: Small cell enhancements, enhanced CoMP, FD-MIMO, NAICS, TDD eIMTA - Increasing mobile data diversity: Device to device communications, UPCON, CDN
  38. 38. Appendix
  39. 39. Lead WG Work Item Title Completion Date WI Description 1 RAN1 Further Downlink MIMO Enhancement for LTE-Advanced 2013.06 RP-121416 2 New Carrier Type for LTE 2013.12 RP-122028 3 Further Enhancements to LTE TDD for DL-UL Interference Management and Traffic Adaptation 2013.12 RP-121772 4 RAN2 Hetnet Mobility Enhancements for LTE 2014.03 RP-122007 5 Support for BeiDou Navigation Satellite System (BDS) for UTRA and LTE 2014.03 RP-130416 6 RAN3 Further enhancements for H(e)NB mobility-Part 3 2013.06 RP-121444 7 Further enhancements for HeNB mobility-X2-GW 2013.09 RP-122006 8 Public Warning System - Reset/Failure/Restart in Warning Message Delivery in LTE 2013.12 RP-130398 9 RAN aspects for SIPTO at the Local Network 2014.03 RP-130372 Lead WG Study Item Title Completion Date SI Description 1 RAN1 Small Cell Enhancements for E-UTRA and E-UTRAN – Physical-layer Aspects 2013.09 RP-122032 2 3D-channel model for Elevation Beamforming and FD-MIMO studies for LTE 2013.09 RP-122034 3 Study on LTE Device to Device Proximity Services 2014.03 RP-122009 4 Provision of low-cost MTC UEs based on LTE 2013.06 RP-121441 5 Network-Assisted Interference Cancellation and Suppression for LTE 2013.12 RP-130404 6 RAN2 Small Cell Enhancements for E-UTRA and E-UTRAN – Higher-layer aspects 2013.09 RP-122033 7 WLAN/3GPP Radio Interworking 2013.09 RP-122038 8 RAN aspects of Machine Type and other mobile data applications Communications enhancements 2013.09 RP-130396 9 RAN3 Next-generation SON for UTRA and LTE 2013.09 RP-122037 10 RAN Enhancements for UMTS/HSPA and LTE Interworking 2013.12 RP-122016 11 Study on Energy Saving Enhancement for E-UTRAN 2013.12 RP-122035 Approved work items for Release 12 Approved study items for Release 12