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 Evolution

3GPP 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

2013 2011 2012

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

Dual Layer Beamforming MIMO Enhancements MIMO

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 S U D D D D

eIMTA

M2M Optimization

New Carrier Type

Mobile Relay

Small Cell Amorphous RAN

D2D

3D MIMO

Heterogeneous Interworking

FeICIC

EPDCCH

Data

ePDCCH

PD

CC

H

GW MME

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

Offloading

3GPP 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 Diversification

3GPP 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 Enhancements

SCE: 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 R1-130748

SCE : 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 Band

SCE : 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

PicoMacro UE

f 1

f 2

Discovery signal only

3D 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-array

13

3D MIMO: Use Case

UE specific vertical/horizontal beamforming

Dynamic TX/RX beamforming

Carrier/RAT specific tilting

Vertical/horizontal sectorization

Source: www.nokiasiemensnetworks.com

3D 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 UEs

D2D: 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 only

D2D: 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 incorporation

eIMTA: 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 S U D D 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 interference

NCT: 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

Signal

LTE/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

eNBBeNBA

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

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Other Technologies for Rel. 12 & Onward [2]