Evolution of 3GPP LTE-Advanced Standard
toward 5G
KRNet
2013. 6. 24.
LG Electronics
Byoung-Hoon Kim
(bh.kim@lge.com)2
802.20
UMB* 1G 2G
High
(~350Km/h)
Medium
(Vehicular)
Low
(Nomadic)
Peak Data Rate 14.4 Kbps 144 Kbps 384 Kbps ~ 50 Mbps ~100 Mbps
CDMA
GSM
AMPS
W-CDMA
HSDPA/HSUPA
CDMA2000/EV-DV/DO
1995 2000 2005 2010
802.16e
802.11a/b
802.16a/d
Mobility
3G
802.11n
IMT-Advanced
Standard
~1 Gbps
3G Ev.
WLAN
802.11ac/ad
We are here
802.16m ?
LTE*
Rel’8/9
LTE-A
Rel’10/11
Communication Standards Evolution3GPP LTE Evolution
OFDMA: Orthogonal Frequency Division Multiple Access, MIMO: Multiple Input Multiple Output, EPC: Enhanced Packet Core, M2M: Machine-to-Machine,
D2D: Device-to-Device, SON: Self Organizing Network, FeICIC: Futher Enhanced Inter-Cell Interference Coordination, MDT: Minimization of Driving Test,
EPDCCH: Enhanced Physical Downlink Control Channel, CoMP: Coordinated Multi-Point Operation, eIMTA: Enhanced Interference Mitigation & Traffic Adaptation
3GPP
LTE
2011 2012 2013
LTE-A Rel.10
LTE-A Rel.11
LTE-A Rel.12
2014
OFDMA
3GPP Workshop for Rel.12 & Onward
(Ljubljana, 6/11-12, 43 company presentations)
Rel.13
2008 2009 2010
LTE Rel.9
LTE Rel.8
LTE-A Study
3GPP Workshop for LTE-Advanced
MIMO Dual Layer Beamforming MIMO Enhancements
EPC
Location Based Service
MBMS
Femto Cell
Carrier Aggregation
SON
Relay
MDT
CoMP
D S U U U D S U U U
D S U D D D S U D D
eIMTA
M2M Optimization
New Carrier Type
Mobile Relay
Small Cell
Amorphous RAN
D2D
3D MIMO
Heterogeneous
Interworking
FeICIC
EPDCCH
Data
ePDCCH PDCCH
MME GW
3 4
User Experience Expectation
Intelligent Agent Free & Green
Transportation
Mobile device as
intelligent agent
Knowledge building
Service brokering
Context reasoning
Health
Shopping Restaurant
Lawyer
Traffic
Context gathering
Application Server
Cloud network
 Ambient sensing/adaptation
 Throughput enhancement
 Proximity awareness
 Cost per bit reduction for
end user satisfaction
 Energy saving
UHD Everywhere
 Peak rate enhancement
 Balanced QoS
 Ubiquitous connectivity
Macro
WiFi
More than FHD device
UHD video
Cooperation
Pico/Femto
Offloading3GPP LTE-Advanced Rel.12 & Onward Requirement
5
Source: Morgan Stanley
Source: Cisco
UHD
3D Video
Improved Channel Capacity
to Cope with Traffic Explosion
Improved Data Rates for
Enhanced User Experiences Cost Per Bit Reduction
Improved Backhaul Performance Energy Saving Device & Application Diversification3GPP LTE-Advanced Rel.12 & Onward Core Technology
6
Small Cell / Amorphous RAN
eIMTA
3D MIMO
Enhanced Carrier Aggregation
D2D
LTE/WLAN Radio Interworking
Enhanced Wireless Backhaul New Carrier Type MTC Enhancement
LTE
Wi-Fi
coordination
FDD: Frequency Division Duplexing, TDD: Time Division Duplexing, D2D: Device-to-Device, Het-Net: Heterogeneous Network, MTC Machine Type Communication (M2M)
Reference
Signal
High Frequency

FDD + TDD + Unlicensed Focus Areas in
LTE-Advanced Rel.12~
1. Small Cell Enhancement
2. 3D MIMO
3. Device-to-Device Communication
4. Enhanced Interference Mitigation and Traffic Adaptation
5. New Carrier Type
6. LTE/WLAN Radio Interworking
7. Other EnhancementsSCE: Small Cell Enhancement
Small Cell
Enhancement
 Enhancement of cellular network for indoor and outdoor scenarios using
low power nodes
 To cope with mobile traffic explosion
 With or without macro cell coverage
 Dense or sparse deployment
 Different or same frequency for macro and small cell layers
8 SCE : Use Cases
9
 Small cells cluster scenarios
Common solution for scenario #1, #2, #3
Small cell
Macro cell
Small cell
Note: Overlapping
macro may be
present or not
Coordination
Coordination
F1
F1 or F2 Cluster
Common design for scenarios #1, #2a, #2b, and #3
- Data/control splitting
- Data throughput boosting
- Offloading
- Extended coverage
Source: 3GPP TSG R1-130748SCE : Technical Challenges [1]
 Utilization of Higher frequency bands (3GHz or higher) with wider bandwidth
Dual Connectivity
10
 Relaxation of backhaul requirements
 Function (C/U) splitting between Macro and small cells
High Frequency BandSCE : Technical Challenges [2]
 Cooperation of dense network of distributed transmission points
 UE-centric virtual cells
 Enhanced mobility support (to minimize the handover frequency)
 Radio Interface based synchronization (network listening, UE assistance)
Interference
Management
&
Discovery
11
 Enhanced inter-cell interference coordination & measurement
 Cell on/off, enhanced power control, load balancing
 Support of small cell discovery
Amorphous Cell
Improved
Spectral Efficiency
 Higher order modulation (256 QAM for cellular, EVM & Rx impairment issue)
 Control Signaling Overhead Reduction: Multi-subframe scheduling, cross-subframe
scheduling, control-less subframes
Pico
Macro
UE
f 1
f 2
Discovery signal only3D MIMO: 3 Dimensional Beamforming
3D MIMO
 Advent of Active Antenna System (AAS)
 Each antenna element combined with active transceiver (including PA)
 Massive MIMO antenna elements
 3D beamforming and single/multi-user MIMO based on 2D AAS
12
Coverage for lower vertical
angle
Coverage for higher vertical
angle
Coverage for ground level
Antenna gain
One sub-array
Whole antenna
Antenna attenuation
Higher signal level in
sub-array
Lower signal level in
sub-array
Antenna gain
One sub-array
Whole antenna
Antenna attenuation
Higher signal level in
sub-array
Lower signal level in
sub-array13
3D MIMO: Use Case
 UE specific vertical/horizontal beamforming
 Dynamic TX/RX beamforming
 Carrier/RAT specific tilting
 Vertical/horizontal sectorization
Source: www.nokiasiemensnetworks.com3D MIMO: Technical Challenges
3D Channel Model
 Modeling a 2D array structure at eNB
 3D channel modeling including multipath fading in azimuth and elevation
 Elevation angular spread of departure & arrival (ESD, ESA)
 Mean elevation angle of departure & arrival (MED, MEA)
 Location of UEs in horizontal and vertical domains
 Mobility of UEs in horizontal and vertical domains.
eNB & UE
Design
14
 Decision on the number of antenna units to be supported
 Issues to be considered
 Means to ensure the coverage of common control channels
 RRM measurements and procedures with large number of antenna ports
 Cell edge improvement and interference reduction
 Overheads for reference signals and feedback
 UE complexity (especially for UE-side massive MIMO antennas)
 Impact on legacy UEsD2D: Device-to-Device Communication
D2D
15
 UE directly discovers and communicates with peer UE over-the-air
 Energy-efficient discovery of peer UEs
 Spatial reuse of time/frequency resources
 Latency reduction
 Proximity-based services
SGW/PGW
eNB eNB
UE1 UE2
SGW/PGW
eNB eNB
UE1 UE2
Data path of the evolved packet service (in 3GPP)D2D: Use Cases [1]
Public
Safety
 Public safety message delivery by
UE relaying and information flooding
Commercial
Network
Enhancement
 Out of network coverage
 Emergency when network is destroyed
 Social network
Discover friends in the vicinity
Find people with common interest
 Mobile advertisement
Neighborhood stores
Individual offer
Source: Qualcomm
16
(destroyed)D2D: Use Cases [2]
 D2D scenarios:
– In network coverage
– Out of network coverage
– Partial network coverage
 D2D communication type:
– Unicast
– Groupcast
– Broadcast
– UE relay
17
3GPP D2D
Initial Focus
Within network
coverage
Outside network
coverage
Discovery Non public safety & public
safety requirements
Public safety only
Direct
Communication
At least public safety
requirements
Public safety onlyD2D: Technical Challenges
UE
 Discovery of UEs
 Identification of a certain UE in its proximity in a battery efficient way
 Synchronization and measurement of channels from UEs
 Receive over UL resource (or transmit over DL resource)
 D2D Tx timing relative to UL/DL cellular channel Tx/Rx timing
 Maintenance of dual connectivity
 One link with eNB, the other with UE(s)
 Mitigation of in-band emission
 Group communication, relaying, security, privacy, etc.
eNB
18
 Control of D2D links
 Scheduling of individual D2D transmission and high-level control
 Coordination of interference
 Maximization of spatial reuse without causing serious interference
 Single or multiple-operator scenarios
 Charging, accounting, security, privacy, etc.
 WLAN incorporationeIMTA: Enhanced Interference Mitigation & Traffic Adaptation
eIMTA
19
 Dynamic and flexible resource configuration for TDD
in consideration of traffic load
 eNB transmits DL data in UL resource when DL traffic is heavy.
 Fixed subframe type vs. flexible subframe type
Symmetric Traffic Situation
…
Time 1 Time 2
Resource used for DL/UL
Buffer Status
(Time 1)
UL traffic
DL buffer
UL buffer
Heavy DL Traffic Situation
UL traffic
DL buffer
UL buffer
Buffer Status
(Time 2)eIMTA: Technical Challenges
Power Control
&
Coordinated Scheduling
20
 Subframe-type dependent UL power control and DL measurement
 Separate UL power control parameters for each type of subframes
 Separate DL channel measurement/report each type of subframes
Signaling
 eNB-to-eNB backhaul signaling
 eNB-to-eNB interference power level
 UL/DL traffic condition in each cell
 eNB-to-UE signaling of reconfiguration of DL/UL subframes
 Explicit Layer-1 signaling by a UE group-common control channel
D S U U U D S U U U
D S U D D D S U D D
eNB transmission
in UL resource
A cell operating eNB-to-UE
transmission
A cell operating UE-to-eNB
transmission
UE transmission
in UL resource
eNB-to-eNB interference
UE-to-UE interferenceNCT: New Carrier Type
LTE/WLAN
Radio
Interworking
21
 Reference signal and control overhead reduction relative to LTE
legacy carrier
 Reduced Common Reference Signal (Tracking RS) for
 Improved eNB energy saving, spectral efficiency, interference
coordination, eMBMS services, etc.
 Challenges in RRM measurement and mobility support
 Standalone NCT vs. non-standalone NCT (aggregated to legacy carrier)
Reference
SignalLTE/WLAN Radio Interworking
LTE/WLAN
Radio
Interworking
22
 RAN-level interworking of LTE & WLAN in addition to core network
based interworking mechanisms
 Collocated or non-collocated eNB (LTE) / AP (WLAN): APs controlled by
cellular operators
 WLAN included in operator’s cellular RRM
 Enhancement of access network mobility and selection
- Radio link quality, backhaul quality, load, etc.
 Power efficient WLAN scanning
LTE/WLAN
LTE
WLAN
coordination Other Technologies for Rel. 12 & Onward [1]
 Evolution from previous release/study
– Low cost MTC
 Cost reduction & coverage enhancement for MTC devices
– DL 4 Tx MIMO enhancements
 Feedback enhancement
 Codebook enhancement for 4Tx MIMO
– CoMP Enhancements
 Non-ideal backhaul, RRM, SRS enhancement
– Network assisted advanced receiver
 Receiver performance enhancement through
cooperation between transmitter and receiver
 Mitigate interferences caused by data/control channel
23
eNBB
eNBA
eNBC
X2 interface
UE
Multi-cell MIMO user :
Single-cell MIMO user :
DL UE Data
CSI
Backhaul
Smart
monitoring
Smart Home
Relay Node
(Concentrator)
MTC server
Normal UE
Low cost
MTC devices
Group
Scheduling
D2D– Enhanced MDT (Minimization of Driving Test)
 Smart logging and reporting
– SON enhancements
 Inter-RAT mobility load balancing
– Mobile Relay
 Group mobility support by mobile relay
24
Other Technologies for Rel. 12 & Onward [2]