4 Lf_bt1011_e01_1 Lte Mimo Principle 34

MIMO Principle ZTE University

Objectives 

 After the course, course, you will: will: 

Know the MIMO mode in LTE



Know the benefits of MIMO



Understand the transit mode of MIMO



Know the MIMO Performance and Application

Objectives 

 After the course, course, you will: will: 

Know the MIMO mode in LTE



Know the benefits of MIMO



Understand the transit mode of MIMO



Know the MIMO Performance and Application

Contents 

LTE MIMO Introduction



Transmit Modes Theory Introduction



MIMO Performance



MIMO Application

Inputs and Outputs

Single Input Single Output

Single Input Multi Output

Multi Input Single 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 SISO System： SISO）系统 单输入单输出（ ： C  log

2    (1 | | )  h 2

b / s / Hz

 

 M 

C 

MISO System ：

C 

SIMO System ： 单输入多输出（ SIMO）系统 ： MIMO System ： 多输入多输出（ MIMO）系统 ： C EP

 log 2 [det( I  M

   N

log 2 (1     | hi |2 ) log 2 (1 

  

 N 

HH

)] 

 

i 1  N 

2 | | h  i )

b / s / Hz

 

i 1

m

*

b / s / Hz

 

 log (1  N   ) 2

i

b / s / Hz

i 1

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

 

Why select MIMO ? MIMO increase spatial dimensions freedom for radio resources

Through space-time processing technology, make full use of space resource, to ascend the capacity of the communication system without increasing the spectrum resources and power, improving the reliability and Spectrum efficiency.

MIMO can get more higher channel capacity than SISO/SIMO/MISO

Contents 

LTE MIMO Introduction



Transmit Modes Theory Introduction



MIMO Performance



MIMO Application

MIMO System Model

MIMO System Model

 r 1  r   2    r 

 N r 

  h11  h    21       h 1  N r

h12

h1 N 

h22

h2 N 

hN

r

2

t 

t 

hN

r

N t

  x1    x2     x  

 N t

  n1  n  2       n

MIMO Signal Model Expression

N t 

     

LTE Key Technology---MIMO Theory v11

Encode

Data stream

Channel Interleave

Modulator QPSK 16QAM

Detector

v21 DeMUX

v12

Encode

Channel Interleave

Modulator QPSK 16QAM

Trans mitter

Data stream

Receiver

MUX

Detector v22

Space multiplexing & space diversity leads to higher bit rate.

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 Codebook based Beamforming

Non Codebook based Beam-forming

Contents 

LTE MIMO Introduction



Transmit Modes Theory Introduction



MIMO Performance



MIMO Application

MIMO Simulation Results-Case 1 Cell Spectrum efficiency

 2.2

0.06

0.05 4

1.8

1.4

Cell Edge SE (5% CDF)



0.04 1.34 5

0.04 7

0.042 0.04 5

0.04

1.0

0.03

0.8

0.02

0.4

0.01

0

0

1T2R

1T2R

eNodeB

0.05 4

0.05

UE

0.04 7

MIMO Simulation Results-Case 2 Cell Spectrum efficiency

 2.2

1.8

1.4

Cell Edge SE (5% CDF)

 0.06

0.05 4

1.6763

0.0437

0.04 7

0.04 5

0.03

0.8

0.02

0.4

0.01

2T2R

eNodeB

0.04 5

0.04

1.0

0

0.05 4

0.05

Rank

0

2T2R

UE

0.04 7

MIMO Simulation Results-Case 3 Cell Spectrum efficiency

 2.2

0.06

1.7488

0.05 4

1.8

1.4

Cell Edge SE (5% CDF)



0.04 5

0.04 7

0.04 5

0.04

1.0

0.03

0.8

0.02

0.4

0.01

Rank

0

0.0495

0.05

0

4T2R

4T2R

eNodeB

UE

0.04 7

MIMO Simulation Results Cell Spectrum efficiency

 2.2

Cell Edge SE (5% CDF) 0.06

1.6763

1.8

1.4



1.34

0.04 5

1.7480.05 4 0.04 7

1.0

0.0495 0.05

0.042

0.0437

1T2R

2T2R

0.04

0.03

0.8

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

0.4

0.02

0.01

0

1T2R

2T2R 25%

4T2R 30%

0

4%

4T2R 18%

Simulation Results of Different MIMO Modes FR

Average Cell Throughput （Mbps）

Frequency Efficiency （Mbps/Hz）

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 ISD 500m,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

Contents 

LTE MIMO Introduction



Transmit Modes Theory Introduction



MIMO Performance



MIMO Application

MIMO Modes in LTE 1

Mode 1 Single Antenna Port

High priority for non-MIMO system

2

Mode 2 Transmit Diversity

High priority

3

Mode 3 Open Loop SM

High priority for two antennas, Medium priority for four antennas

4

Mode 4 Closed-Loop SM

High priority for two antennas, Medium priority for four antennas

5

Mode 5 MU-MIMO

Medium/Low priority

6

Mode 6 Codebook BF

Medium priority for four antennas

7

Mode 7 Non Codebook BF

Low priority, especially for LTE FDD

Benefits of Different MIMO Modes in LTE 1

Mode 1 Single Antenna Port

Correspond to Single Antenna Port

2

Mode 2 Transmit Diversity

Provide Diversity Against Fading

3

Mode 3 Open Loop SM

High Mobility Environment

4

Mode 4 Closed-Loop SM

Improve Peak data rates

5

Mode 5 MU-MIMO

Improve system Capacity

6

Mode 6 Codebook BF

7

Mode 7 Non Codebook BF

Improve cell Coverage and Suppress Interference

MIMO Modes in Downlink Physical Channel

Mode1

Mode 2

Mode3 – Mode 7

PDSCH







PBCH





PCFICH





PDCCH





PHICH





SCH





Application Selection of MIMO Modes Cell Center

Cell Edge

Urban Area

High Speed Medium Speed Low Speed（Indoor ）

Cell Edge

Handset Adaptation to MIMO Modes

Mobility Speed Changes

Rank Changes

Location to Cell Changes

2

Transmit Diversity

3

Open-Loop SM

4

Closed-Loop SM

5

MU-MIMO

6

Codebook BF

7

Non Codebook BF

MIMO Modes Conclusion Transmit Scheme

Rank

Channel Correlation

Transmit Diversity (SFBC)

1

Low correlation

Open-Loop SM

2/4

Double Stream Precoding

Mobility Environment

Data Rates

Location in the Cell

High/Medium Speed

Lower Data Rates

Cell Edge

Low correlation

High/Medium Speed

Medium/ Lower

Cell centre/ Cell Edge

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 Ant3

Ant1

Ant2

Ant1

Case 1: Medium Correlation (4  ) 

Ant1

Ant2

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

Ant4

Ant2

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

Ant1 Ant2 Ant3 Ant4 Case 4: High correlation (0.5  ) 

MIMO Deployment Consideration 

Scenario A

46~48F



 Scenario C

43~45F 40~42F 37~39F 34~36F 31~33F 28~30F

Linear Antenna

25~27F 22~24F



Scenario B

19~21F 16~18F 13~15F

10~12F 7~9F 4~6F

Cross-polarization

1~3F