Transcript
Page 1: Dr. Guangyi Liu CMCC

4.5G: boost the experience from user and

operator’s perspective

Dr. Guangyi Liu

CMCC

Page 2: Dr. Guangyi Liu CMCC

CONTENTS

• Progress of TD-LTE network

• Challenges for further development

• Expectation for further evolution

• Summary

2014/10/20

Page 3: Dr. Guangyi Liu CMCC

Progress on CMCC’s TD-LTE network

Base Station

(10^4) 48

>50

2014 up to now 2014 Total

Terminal (10^8)

0.22

1.0

Subscriber (10^4)

2957

5,000

2014 up to now 2014 Total 2014 up to now 2014 Total

Network

Largest LTE network at the end of 2014

International roaming with 8 operators

Traffic

Have balanced 13.4% traffics

4G ARPU:2 X average

4G DOU:6 X average

Customer

Much shorter access Latency to Internet

Better experience for users with video services

Globalization

41 TD-LTE commercial network globally

Guarantee roaming based on robust ecosystem

Page 4: Dr. Guangyi Liu CMCC

6:6:2

Extended Scale

Field Test 2012 Phase 1, 2013

2012 2013

Phase 2,2014

2015

Configuration

Multi-antenna

20M/10MHz,

2DL:2UL,3DL:1UL

TM3/8 adaptation

IRC

UL MU-MIMO

RRM Mobility

Static ICIC

Interworking 4G/3G data

reselection

CSFB to GSM

4G/3G data

redirection

VoLTE with

SRVCC

8Rx UL CoMP

Others SON SON

enhancement

300km/h high-

speed scenario

Deployed Features Features deployed in the network

Features in Trial

eMBMS,

service Caching

8Rx TM9/DL

CoMP

Wireless big data

Carrier agg.,

Relay

eMBMS

2014

Page 5: Dr. Guangyi Liu CMCC

Band 39:TDD

825 835 870 880 889 915 934 960 909 954 1710 1755 1785 1850 1735 1830 1880 1805

Band 3: FDD Band 3: FDD Band 8: FDD Band 8: FDD FDD FDD

2025 2010

B34: TDD

2400 2300

Band 40: TDD

2130 2125 2170 2110

Band 1: FDD

1920 1955 1980 1935

Band 1: FDD

1880 1900 2635 2575 2690 2500

Band 41: TDD

1940 2145 2320 2370

CM

CC

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Converged FDD/TDD networking is a sufficient way for MBB

FDD

Band 8: 900MHz 2x20MHz for GSM

Band 3: 1800MHz 2x25MHz for GSM

TDD

Band 34: 2010-2025MHz for TD-SCDMA

Band 39: 1880-1900MHz for TD-SCDMA&TD-LTE

Band 40: 2320-2370MHz for TD-SCDMA&TD-LTE (indoor only)

Band 41: 2575-2635MHz for TD-LTE

Note: 1785-1805MHz has limited applications for broadband wireless access,

e.g. providing BWA service in some airports

Page 6: Dr. Guangyi Liu CMCC

1.Coverage-based

mobility management

Object: Balance the load and

increase bandwidth efficiency

2. Load-balancing

handover

Converged LTE TDD/FDD networking is in test

Object: Guarantee coverage and

seamless service continuity

TDD

FDD

3. LTE TDD/FDD

joint operation

Object: utilize FDD/TDD resources

simultaneously and maximize

bandwidth efficiency

For the first 2 phases, the industry is mature enough for commercial deployment

The convergence can be further enhanced by deploying TDD/FDD joint operation

in the near future

Industry is mature

enough for commercial

deployment

Page 7: Dr. Guangyi Liu CMCC

Well supported by both network equipment/terminal industry, ready for commercial deployment. All

5-mode or 4-mode smartphones can support handover between TD-LTE and LTE FDD

since H2 of 2013

Already been enabled in more than 6 commercial networks

Phase I: Coverage-based Mobility Management

Chipset

Network Equipment

Operator Enabled in>6 commercial networks

Industry & Commercial Deployment Status

Idle Reselection success rate: 100%, latency~31 ms

Handover success rate 100% control plane latency : 16~18 ms user plane latency:55~56 ms

Performance at the same level as inter-frequency handover within TDD or FDD

Performance in China Mobile Hong Kong (CMHK)

Page 8: Dr. Guangyi Liu CMCC

Network equipment: well supported, ready for commercial deployment

Terminal: no additional requirement needed as long as UE supports TDD/FDD handover,

well supported

In

Phase II: Load-Balancing Handover

Industry Status

Inter-Vendor Load-Balancing:Different vendors may have different definitions for

load evaluation/user selection/user transfer/load information exchange, which

might degrade the performance. Definitions needs to be unified to enhance user

experience/network efficiency during load-balancing handover

Notes on Commercial Deployment

eNB1 eNB2

Load eval.

User Selection &load transfer

Response Status Request

Response Status Response

Response Status Update

Handover Request

Handover Response

Standardization regarding inter-vendor

load-balancing have been done in both

3GPP and NGMN. Industry promotion can

be done when needed

Page 9: Dr. Guangyi Liu CMCC

Scenario 1 TDD-FDD co-baseband, single vendor

Scenario2 TDD-FDD non-co-baseband, multi-vendor

Solution: TDD-FDD Carrier Aggregation Solution: TDD-FDD Dual Connectivity

Non-ideal backhaul

(e.g., X2)

FDD Carrier

TDD Carrier

TDD eNBFDD eNB

TDD/FDD

Dual-mode UE

(Double Tx)

FDD Carrier

TDD Carrier

TDD/FDD

Dual-mode eNB

TDD/FDD

Dual-mode UE

(Single Tx)

Phase III: Joint Operation

• Peak data rate (theoretical): 20M TDD+20Mx2 FDD = 260 Mbps • Dynamic load balance (CA, ~ms level): 10% ↑ cell average throughut (simulation)

30% ↑ cell edge throughput (simulation)

Benefits

Standardization Progress & Industry Status

• Standard Progress: Both TDD-FDD CA and Dual Connectivity are ongoing in 3GPP R12; • Industry status: Initial PoC and field trial has been done by some network vendors;

Freq.

Finished B8(900M)+B40(2.3G) B1(2.1G)+B42(3.5G) B19(850M)+B42(3.5G)

Ongoing B1(2.1G)+B41(2.6G) B3(1.8G)+B40(2.3G) B26(850M)+B41(2.6G) B3(1.8G)+B41(2.6G)

Page 10: Dr. Guangyi Liu CMCC

Industry Status of TDD-FDD Joint Operation

TDD as Pcell:DL peak data rate 250Mbps

FDD as Pcell:DL peak data rate 250Mbps

PoC demo of TDD-FDD CA in MAE 2014 Field Trial of Dual connectivity in Shanghai

MSA enhances the peak data rate and cell-edge throughput

MSA balance load between Macro and small cell by load and inteference condition

Peak data rate Cell-edge throughput

Balance by load Balance by interference

• 20M TDD config.2 (band41)+ 20*2 FDD(band8); • Both TDD and FDD can be configured as Pcell;

TDD-FDD CA enhance peak data rate

• 10M TDD (3.5G)+ 10*2 FDD (2.6G);

Page 11: Dr. Guangyi Liu CMCC

CONTENTS

• Progress of LTE network

• Challenges for further development

• Expectation for further evolution

• Summary

2014/10/20

Page 12: Dr. Guangyi Liu CMCC

New Challenges for CMCC

• High data rate

• Traffic booming

• Delay sensitive

• Always online

• Seamless mobility

• ……

2014/10/20

• Densified deployment

• Heterogeneous architecture

• Multi-RAT co-existence

• Various terminal types

Page 13: Dr. Guangyi Liu CMCC

Challenges for TD-LTE Network Coverage

Challenges

High frequency band cause big path loss

Insufficient deep indoor coverage,high cost by deploy DAS

Co-exist of multi-band

and multi-system need

to be considered

Hard to obtain or to get site locations for macro cells

Flexible eNB types would be helpful !

Page 14: Dr. Guangyi Liu CMCC

Flexible eNB types is the way for deep coverage

Macro cell Micro cell Pico/Nanocell Nanocell

Macro coverage dead spot and

hot spot coverage Home coverage

Public indoor coverage

Macro

RRU

Distributed macro

Micro RRU

BBU

Integrated micro

Distributed micro Relay

Enterprise

Nanocell

Residential

Nanocell

Micro repeater

Active

antenna

BBU

Pico RRU

Small Cells

Page 15: Dr. Guangyi Liu CMCC

Small Cells become extremely important

Mobile data traffic exploding

High capacity demand

Multi-layer architecture

More small cells have to be deployed

• ~5X small cells vs. macro cells

without new frequency introduced

• ~3X small cells vs. macro cells

with new frequency introduced

Urban Village/Town

Rural

Microcell

DAS Pico/Nanocell

Microcell

Macrocell

Macrocell

Macrocell

Relay

Relay

Micro

Micro Pico/nano

Pico/nanocell

Page 16: Dr. Guangyi Liu CMCC

Challenges for Small Cell application

More dependent on SON Complex interference control

& mobility management

Others?

Multi-mode support O&M

Business model Cost control

Page 17: Dr. Guangyi Liu CMCC

CONTENTS

• Progress of LTE network

• Challenges for further development

• Expectation for further evolution

• Summary

2014/10/20

Page 18: Dr. Guangyi Liu CMCC

Key Issues Remained for Further Study

Spectrum

Explore the potentialities of convergence, e.g.

multi-RAT coordination, TDD/FDD joint

operation based on CA and DC etc.

Find new resources, e.g.

unlicensed

Network Capability

Deep Coverage

Voice and SON

Improve the deep coverage,

e.g. dense small cell

Improve the special coverage,

e.g. high rise building, etc.

Improve the capability , e.g.

UL64QAM, multiple CC

aggregation

Automatically respond the

metrics required by operators,

e.g. SINR, VoLTE related

Voice related optimization, e.g.

CSFB, VoLTE, etc.

More accurate and service-aware

management, e.g. RAN caching,

traffic localization, etc.

Page 19: Dr. Guangyi Liu CMCC

Converged Network to boost the user experience

Spectrum Flexibility

III:FDD/TDD Joint Operation

Evolution

I:Coverage Based

Load Increasing

II:Load Balancing

MRC (Multi-RAT Connectivity)

The first and second phase of FDD/TDD convergence has been tested, and coverage

based handover and load balance could be introduced

WLAN

MRC Controller

3G 2G

Traffic Steering Joint Radio Resource Allocation

4G

Multi-RAT Management

CA & DC

Page 20: Dr. Guangyi Liu CMCC

Licensed Assisted Access

• How to use the unlicensed band?

2014/10/20 20

Carrier Aggregation is supposed to be the only solution for LAA at least in R13

Carrier Aggregation Standalone

Perform interference handling Avoid congestion on unlicensed band Guarantee QoS Separate signaling and data

Possible for normal UE to deploy LTE Hard for interference handling

Licensed Band Unlicensed Band

YEAR Spectrum

Requirements

China 2015 570-690MHz

2020 1490-1810MHz

U.S. 2014 822 MHz

Australia 2020 1081 MHz

Russia 2020 1065 MHz

GSMA 2020 1600-1800MHz

ITU 2020 1340-1960MHz

• 687MHz has been allocated in China

• Not so much potential spectrum available for IMT below 6GHz

• Spectrum will be the most important aspect for IMT development

• Unlicensed spectrum requirements

Page 21: Dr. Guangyi Liu CMCC

UL Enhancement

• Spectral efficiency limitation for uplink transmission – E.g., maximum 16QAM or 64QAM, which limits higher transmission spectral efficiency

regardless higher transmission power

– Tx EVM limits higher SINR at receiver side, which limits higher transmission spectral efficiency

16QAM,8Rx

For example, ~90% users has SINR higher than MCS_16 - Assuming maximum 16QAM, 1Tx8Rx

~50% users has SINR higher than MCS_16 - Assuming maximum 16QAM, 1Tx2Rx

• Possible enhancement, especially for good SNR users • Uplink Dual Transport Blocks (TB) transmission for 1Tx UE (UL_1Tx_dualTB) can

offer gains from uplink peak data rate and spectral efficiency perspective[1]

• Utilization of uplink 64QAM (UL_64QAM) [2] Note:

[1] RP-140663 New Work Item Proposal: support of uplink 64QAM in LTE Huawei, HiSilicon

[2] RP-141287 Uplink dual transport block transmission to enhance uplink performance CMCC

Page 22: Dr. Guangyi Liu CMCC

3D-MIMO

UMa/UMi Indoor

RX

RX

RX

TX

Highrise

2D-MIMO 3D-MIMO

Increased receive energy

Reduced inter-cell-interference

Serve more users simultaneously

Wide beam in elevation domain Narrower beam in elevation domain

Fixed downtilt Larger downtilt for cell-center user

Can separate users in horizontal domain only

Can separate users in both horizontal and vertical domain

Page 23: Dr. Guangyi Liu CMCC

VoLTE

OTT

M2M

Video

The aim is to improve the radio access control and user data transmission in a

differentiated manner on a service-aware basis.

Service-Aware Management

• SCM: Smart Congestion Management

•Differentiate the radio access probability Control signaling access

enhancement

•UPCON: User Plane Congestion management

•Differentiate the user data transmission

User data management optimization

• LIPA/SIPTO

•Differentiate the local service provision and routing Service localization

• Popular service cached in RAN side

•Reduce backhaul and Core load RAN Caching

•Adaptive service distribution and convergence

•Consistent service experience Service continuity

• Finer gratuity of QoS handling w.r.t. signaling and user data treatment

Page 24: Dr. Guangyi Liu CMCC

Small Cell Enhancement

256QAM

Small Cell On/off and discovery

Dual connectivity

Radio-Interface Based Synchronization

34% peak throughput gain vs. 64QAM

Average spectrum efficiency 16%↑

Maximum +/- 1.5us timing error supporting 4 stratum levels Supporting network listening between inter-vendor small cells

User peak throughput 90%↑

Better user mobility Energy saving, interference mitigation, off-loading Average spectrum efficiency 10%↑

Non-idea backhaul

(e.g.,X2)

User Plane D

ata

User Plane Data

Macro eNBSmall cell

Carrier 1

Carrier 2Small cell cluster

Cell discovery

Small cell on/off

· Cell 1 (on) · Cell2 (off) · Cell 3 (off) · Cell 4 (on)

· Cell 5 (off)

Macro eNB

256QAM

1 2

3 4

5

Dual Connectivity

Page 25: Dr. Guangyi Liu CMCC

MDT Enhancement

• Motivation • VoLTE: Deployment of VoLTE of

most operators is this year • SINR: Be used to detect

coverage problems and access network performance

• Towards eMDT • Specify VoLTE and video related

measurements and corresponding collection.

• Specify SINR-like measurement and collection

• The general motivation of MDT

– Decrease the cost of drive testing

– Avoid additional emission of CO2

– Extend time and space for drive testing

Page 26: Dr. Guangyi Liu CMCC

Voice Related Enhancement

CSFB ➡ VoLTE

• CSFB: UE automatic fast return after CSFB to GSM – Save the delay of returning LTE (about

0.4-1.9s), while the cell reselection delay is more than 40s

– Standardization needed, both CSFB to GSM and 3G

• VoLTE SPS: Unsatisfied Performance – Standard limitation on max MCS (below 15) – Scheduler has to be prepared for long term (e.g.200 ms) RF condition thus

sacrifice too much radio resource – Clarification needed for SPS + C-DRX

• eSRVCC: long preparation time & interruption time – prep time(asking 2G for resource reservation) takes 1 - 2s due to long signaling chain, making HO vulnerable to failure – User plane interruption time up to 800ms, optimization needed

Page 27: Dr. Guangyi Liu CMCC

CONTENTS

• Progress of LTE network

• Challenges for further development

• Expectation for further evolution

• Summary

2014/10/20

Page 28: Dr. Guangyi Liu CMCC

Summary

• Converged FDD/TDD networking becomes a trend

• Heterogeneous network is the flexible way for deep coverage and capacity expansion

• Further enhancement is expected to

– boost the network capacity and user experience

– simplify the network optimization and maintenance

2014/10/20

Page 29: Dr. Guangyi Liu CMCC

THANKS!


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