MIMO Principle

ZTE University

Objects

After the course,you will: Know the MIMO mode in LTE Know the benefits of MIMO Understand the transit mode of MIMO Know the MIMO Performance and Application

Content

LTE MIMO Introduction

Transmit Modes Theory Introduction

MIMO Performance

MIMO Application

Inputs and Outputs

Single Input Single Output Multi Input Single Output

Single Input Multi Output Multi Input Multi Output

What is MIMO?

MIMO (Multiple Input Multiple output) A set of techniques that rely on the use of multiple antennas at

the receiver and/or transmitter. It can be used to achieve improved system capacity and improved coverage area.

LTE MIMO Mode

MIMO System Capacity

多输入多输出（ MIMO ）

系统 ：

单输入多输出（ SIMO ）

系统 ：

22

1

log (1 | | ) / /M

ii

C h b s Hz

2

21

log (1 | | ) / /N

ii

C h b s HzN

*2 2

1

log [det( )] log (1 ) / /m

EP M ii

C I HH b s HzN N

In MIMO system, the number of antenna is related with the system capacity.

22log (1 | | ) / /C h b s Hz 单输入单输出（ SISO ）系统 ：

MISO System ：

MIMO System ：

SIMO System ：

SISO System：

Why select MIMO ?

Content

LTE MIMO Introduction

Transmit Modes Theory Introduction

MIMO Performance

MIMO Application

MIMO System Model

11 12 1 1 11

21 22 2 2 22

1 2

t

t

t tr r r r t

N

N

N NN N N N N

h h h x nr

h h h x nr

x nr h h h

MIMO Signal Model Expression

MIMO System Model

LTE Key Technology---MIMO Theory

Space multiplexing & space diversity leads to higher bit rate.

Receiver

Data stream

EncodeEncode

EncodeEncode Channel

Interleave

ChannelInterleave

ChannelInterleave

ChannelInterleave

ModulatorQPSK

16QAM

ModulatorQPSK

16QAM

ModulatorQPSK

16QAM

ModulatorQPSK

16QAM

DetectorDetector

DetectorDetector

MUXMUX

Data stream

v12

v21

v11

v22

TransmitterDeMUX

DeMUX

Structure of Downlink Reference Signals

Transmit Diversity （ 2 Antennas）

SFBC + FSTD

SFBC for two antenna ports

SFBC + FSTD for four antenna ports

Application Scenario for SFBC SFBC enhance system coverage SFBC application scenario

Large Delay CDD

Spatial Multiplexing

Application Scenario for Closed loop SM

Notes: Support antenna ports 2/4; Support one codeword and two codeword; Require RI and PMI feed back from terminal; RANK=1 corresponds to one codeword; RANK>=2 corresponds to two

codeword; One codeword is referred to codebook beam-forming; Be suitable for users with higher SNR in the centre of the cell

Application Scenario for Beam-Forming

Low correlation antenna

High correlation antenna

Beam-Forming in LTE

Content

LTE MIMO Introduction

Transmit Modes Theory Introduction

MIMO Performance

MIMO Application

MIMO Simulation Results-Case 1

Cell Spectrum efficiency Cell Edge SE (5% CDF)

eNodeB UE

0.045

0.047

0.054

1T2R0

0.4

0.8

1.0

1.4

1.8

2.2

1.34 0.045

0.047

0.054

1T2R0

0.01

0.02

0.03

0.04

0.05

0.06

0.042

MIMO Simulation Results-Case 2

Cell Spectrum efficiency Cell Edge SE (5% CDF)

Rank

eNodeB UE

0.045

0.047

0.054

2T2R0

0.4

0.8

1.0

1.4

1.8

2.2

1.6763

0.045

0.047

0.054

2T2R0

0.01

0.02

0.03

0.04

0.05

0.06

0.0437

MIMO Simulation Results-Case 3

Cell Spectrum efficiency Cell Edge SE (5% CDF)

0.045

0.047

0.054

4T2R0

0.4

0.8

1.0

1.4

1.8

2.2

1.7488

0.045

0.047

4T2R0

0.01

0.02

0.03

0.04

0.05

0.06

0.0495

Rank

eNodeB UE

MIMO Simulation Results

Cell Spectrum efficiency Cell Edge SE (5% CDF)

46dBm/Antenna Macro ISD = 500m, 2*2 MIMO

0.045

0.047

0.054

4T2R0

0.4

0.8

1.0

1.4

1.8

2.2

1.748

4T2R0

0.01

0.02

0.03

0.04

0.05

0.06

0.04951.6763

2T2R

1.34

1T2R

0.0437

2T2R

0.042

1T2R25% 30% 4% 18%

Simulation Results of Different MIMO Modes

　 　FR

Average Cell Throughput（ Mbps）

Frequency Efficiency（ Mbps/H

z）

Cell Edge Data Rates（ Mbps）

Cell Edge Frequency Efficiency

（ Mbps/Hz）

Case 1

43dBm/Antenna Macro ISD =500m,10,2*2MIMO,Rank

Adaptive,20dB, 3km/h 1 8.5631 1.5774 0.2751 0.0507

Case 2

33dBm/Antenna Macro ISD = 500m,4TxBF,Single Stream,20dB, 3km/h 1 13.9773 2.5747 0.9195 0.1694

Case 3

33dBm/Antenna Macro ISD500m,4TxBFprecoding,

Dual Stream,20dB, 3km/h 1 13.4308 2.4741 0.8935 0.1646

Case 1

43dBm/Antenna Macro ISD = 500m,2*2MIMO,Rank Adaptive,20dB, 3km/h 3 21.7142 1.3333 1.0842 0.0666

Case 2

33dBm/Antenna Macro ISD = 500m,4TxBF,Single Stream,20dB, 3km/h 3 18.6087 1.1426 1.9028 0.1168

Case 3

33dBm/Antenna Macro ISD = 500m,4TxBF,precoding,Dual

Stream,20dB, 3km/h 3 28.6932 1.7619 2.2303 0.1366

Content

LTE MIMO Introduction

Transmit Modes Theory Introduction

MIMO Performance

MIMO Application

6 Mode 6 Codebook BF

High priority

High priority for two antennas, Medium priority for four antennas

Medium/Low priority

Medium priority for four antennas

1 Mode 1 Single Antenna Port

2 Mode 2 Transmit Diversity

3 Mode 3 Open Loop SM

4

5

7

Mode 4 Closed-Loop SM

Mode 5 MU-MIMO

Mode 7 Non Codebook BF

High priority for non-MIMO system

High priority for two antennas, Medium priority for four antennas

MIMO Modes in LTE

Low priority, especially for LTE FDD

6 Mode 6 Codebook BF

Provide Diversity Against Fading

Improve Peak data rates

Improve system Capacity

Improve cell Coverage and Suppress Interference

1 Mode 1 Single Antenna Port

2 Mode 2 Transmit Diversity

3 Mode 3 Open Loop SM

4

5

7

Mode 4 Closed-Loop SM

Mode 5 MU-MIMO

Mode 7 Non Codebook BF

Correspond to Single Antenna Port

High Mobility Environment

Benefits of Different MIMO Modes in LTE

MIMO Modes in Downlink Physical Channel

Mode1 Mode 2 Mode3 – Mode 7

PDSCH PBCH

PCFICH PDCCH PHICH SCH

Application Selection of MIMO Modes

Cell EdgeCell Center

Urban Area

High Speed

Cell Edge

Low Speed （ Indoor ）

Medium Speed

Handset Adaptation to MIMO Modes

2 Transmit Diversity

3 Open-Loop SM

4

5

7

Closed-Loop SM

MU-MIMO

Non Codebook BF

6 Codebook BF

Mobility Speed Changes

Rank Changes

Location to Cell Changes

MIMO Modes Conclusion

Transmit Scheme

Rank Channel Correlation

Mobility

Environment

Data Rates Location in

the Cell

Transmit Diversity

(SFBC)

1 Low correlation

High/Medium

Speed

Lower Data Rates

Cell Edge

Open-Loop SM 2/4 Low correlation

High/Medium

Speed

Medium/

Lower

Cell centre/

Cell Edge

Double Stream Precoding

2/4 Low correlation

Low Speed Higher Date rates

Cell Centre

MU-MIMO 2/4 Low correlation

Low Speed Higher Date rates

Cell Centre

Codebook

Beam-forming

1 High correlation

Low Speed Lower Date rates

Cell Edge

Non Codebook

Beam-forming

1 High correlation

Low Speed Lower Date rates

Cell Edge

LTE Antenna Correlation

Two antenna at eNB Four antenna at eNB

Case 2: Low Correlation (10) Be suitable for above 2GHz

Ant1 Ant2

Case 3: Low Correlation(4 or 10 between two Pairs)

Ant1 Ant2

Ant3 Ant4

Case 4: High correlation (0.5)

Ant1 Ant2 Ant3 Ant4

Case 1: Medium Correlation (4)

Ant1 Ant2

MIMO Deployment Consideration

Scenario A

Scenario B

Scenario C

Linear Antenna

Cross-polarization1~3F

4~6F

7~9F

10~12F

13~15F

16~18F

19~21F

22~24F

25~27F

28~30F

31~33F

34~36F

37~39F

40~42F

43~45F

46~48F