DL TM8 Based Dual User Single Layer MU-MIMO

DL TM8 based Dual User Single Layer MUMIMO Network Engineering Information LTE1169 RL35 Please always check the latest version of this NEI slides!

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History and Acknowledgemen Acknowledgements ts

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History Version

Author

Date

Reason for update

Acknowledgements Maciej Maci ej Pol (MBB CS NE LTE LTE TDD & Performan Performance ce PL) – PL) – scheduler aspects section

Open Issues

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Open issues Item

Description

Status/comments

LTE1169 – TM8 based DL MU-MIMO

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Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Introduction

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• First Multi-User MIMO feature in NSN’s LTE release! • LTE1169 “DL TM8 based Dual User Single Layer Multi User MIMO” allows to transmit signal to 2 users on the same time and frequency resources simultaneously by using spatial multiplexing • Feature uses 3GPP Transmission Mode 8 (TM8) • LTE1169 reuses RL25 LTE541 “Single User Dual Layer Beamforming” feature for multi-user transmission. 3GPP Rel. 9 compliant UEs are required. •  According to system level simulations, average cell throughput gain of up to 10%, cell edge throughput gain up to 63% (simulation results) • Neither cell peak throughput nor UE peak throughput is not impacted with LTE1169 feature • UEs will be multiplexed if their correlation is low and they report sufficiently high CQI • Only Single Layer beamformed UEs are multiplexed. Dual Layer beamformed UEs are not affected

Introduction

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before & after 

Before LTE1169: Cell uses LTE541 Dual Stream Beamforming

After LTE1169: Increase in cell DL throughput made possible by sharing some of the resources by MU-MIMO UEs

Green UE gets 9 RBGs multiplexed with red UE

  s    G    B    R    B    N   e

Green UE gets 5 RBGs

Red UE gets 7 RBGs

  s    G    B    R    B    N   e

Red UE gets 9 RBGs multiplexed with green UE

Blue UE can be now scheduled in this TTI

Blue UE not scheduled  – lack of resources

Please note: all MU-MIMO candidates are Single Layer TM8 UEs only!

Introduction

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Beamforming Modes in NSN

• Currently there are 2 beamforming modes in NSN •

•

Single Stream Beamforming uses 3GPP Transmission Mode 7 - Specified in 3GPP Rel.8 - Implemented in RL25 as LTE493 feature - As name suggests, supports only 1 spatial multiplexing layer 

dlMimoMode = Single Stream Beamforming (50)

Dual Stream Beamforming uses 3GPP Transmission Mode 8 - Specified in 3GPP Rel.9 - Implemented in RL25 as LTE541 feature dlMimoMode = Dual Stream Beamforming (60) - Can support 2 spatial multiplexing layers with beamforming on •   Beamforming+MIMO - Can also support 1 spatial multiplexing layer if radio conditions are unfavorable (CQI, RI) - Switching between 1 and 2 codewords is done within the TM8 • This is referred to as Dual Layer/ Single Layer transmission

There is no switching between TM7 and TM8 in NSN!

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Technical Details

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Dependency table

FDD LTE

RL release

eNB

NetAct

Release/version

Not supported

-

-

TDD LTE

RL release

eNB

NetAct

Release/version

RL35

LNT3.0

OSS5.5

FlexiZone Micro (FZM)

RL release

eNB

NetAct

Release/version

Not supported

-

-

HW & IOT

HW requirements

MME

SAE GW

UE

Release/version

FSMr3

-

-

3GPP Rel .9

Technical Details

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LTE 541 Dual Stream Beamforming refresher (1/3) •

LTE1169 is built “on top” of LTE541 Dual Stream Beamforming feature

•

By applying carefully chosen complex weights to the antenna elements, transmit beam can be steered in the direction of UE

•

“Hybrid beamforming” is used -> long-term and short-term beamforming weights combination

•

Long-term weights rely on averaged UL channel observations

•

Short term weights rely on instantaneous UL channel observations

•

Only PDSCH allocated to UE is beamformed. Other DL channels (PDCCH specifically) are not beamformed u4 u3

CW0

w11

w12

From layer mapper 

u1

w1

1

w5 2 w2

w21

CW1

6

w6

w3

3

7

Single/Dual stream

w7

w4

4

w8

Short term

5

l / 2

w22

CW1 present if dual layer is enabled

u2

Long term

8

Technical Details

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LTE 541 Dual Stream Beamforming refresher (2/3) •

Beamforming needs channel knowledge at the transmitter -

Channel coefficient == how does a channel change theamplitude and phase of the symbol

•

In TDD there is channel reciprocity (UL and DL have same channel coefficients)

•

Channel information is obtained from UL Sounding Reference Symbols -

Q: Why? •

It can cover whole UL/DL band

•

Is sent regardless of PUSCH transmission

Channel coefficient h how the channel changes the transmitted symbol in terms of amplitude and phase

Received symbol

Transmitted symbol

1

5

2

6

Q

Channel coefficients of polarization group 1  Amplitude

3

7

Channel coefficients of polarization group 2

I

Phase

h1,1 h1,2 h1,3 h1,4

4

8

h 2,1 h 2,2 h 2,3 h 2,4

Technical Details

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LTE 541 Dual Stream Beamforming refresher (3/3)

• How the long term weights are calculated?

First eigenvector can be attributed to the dominant propagation path.

1) Calculate spatial channel covariance matrix: R inst

Using the first EV weights will form a beam in the direction of the dominant path.

 n     h ,1  h ,1  h ,2  h ,2   H

i

i

H 

i

i

i

Sum over all PRBs Channel coefficients of polarization group 1

Channel coefficients of polarization group 2

2) Average in time  Rave (n)

     Rave

(n  1)  (1   )  Rinst (n)  H 

3) Do the eigendecomposition:  Rave  U    U 

The first (dominant) eigenvector of  Rave (first column of U  ) is the long term weighting vector.

The same long term weighting vector is applied to both polarization groups. It is also the same for all UE’s PRBs

Technical Details

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Reference Symbols in DL •

In LTE, reference symbols are associated with DL transmission

•

Reference symbols are used (among others) to allow the UE to estimate the wireless channel coefficients for coherent symbol demodulation

•

Beamformed channels have different coefficients than non-beamformed channels.

-

Channel coefficients derived from non-beamformed channels are useless when it comes to beamformed channel demodulation

Beamformed PDSCH #1 PDCCH (non-beamformed)

Beamformed PDSCH #2

Cell-specific Reference Symbols (non-beamformed)

Non-beamformed PDSCH #3

Technical Details

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UE Specific Reference symbols (DM-RS) •

In LTE Rel-9, two layers of UE-specific reference signals have been introduced. They are called Demodulation Reference Signals (DMRS, sometimes DRS abbreviation is used)

•

DM-RS are sent with each beamformed PDSCH transmission -> user specific RS

•

DM-RS are used by the UE to properly demodulate PDSCH. They are not used for CQI estimation.

•

Cell-specific RS are sent regardless of DM-RS. They are used for demodulation of non-beamformed data and CQI calculation

•

DM-RS for antenna port 7 and 8 occupy same space in DL resource grid. They are separated by Orthogonal Cover Code (OCC)

•

DM-RS are additional overhead for PDSCH   s   e   m   a   r    f    b   u   s    k   n    i    l   n   w   o    d   r   e    h    t   o    l    l    A

l 



0

 R7  R7

 R7  R7

 R8  R8

 R8  R8

 R7  R7

 R7  R7

 R8  R8

 R8  R8

 R7  R7

 R7  R7

 R8  R8

 R8  R8

l 



6 l 

even-numbered slots

Cell RS (ports 0,1,2,3)

DM-RS



0

l 



odd-numbered slots

 Antenna port 7 Antenna port 7

6

l 



0

l 



6 l 

even-numbered slots



0

l 



odd-numbered slots

Antenna port 8 Antenna port 8

6

Technical Details

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Transmission Modes associated with beamforming

TM7≠TM8 with single stream! Single Stream Beamforming is based on 3GPP Transmission Mode 7 (TM7). Antenna port 5 is used for transmitting beamformed PDSCH data

Stream Beamforming is based on Transmission Mode •DualDual Stream Beamforming is 3GPP based on 3GPP TM 8 8 (TM8). - uses beamforming over antenna ports 7 and 8 Antenna ports 7 and/or 8 are used for transmitting beamformed PDSCH data.

Specified in 3GPP Rel. 8.

Specified in 3GPP Rel. 9.

 R5

 R5

 R5

 R5

 R5

 R5

 R5

 R5

 R5

 R5

l 



0

  s   e   m   a   r    f    b   u   s    k   n    i    l   n   w   o    d   r   e    h    t   o    l    l    A

 R5

 R5

l 

e ve n- nu mb er ed s lo ts



6 l 



0

o dd -n um be re d s lo ts

Antenna port 5

l 



 R7  R7

 R7  R7

 R8  R8

 R8  R8

 R7  R7

 R7  R7

 R8  R8

 R8  R8

 R7  R7

 R7  R7

 R8  R8

 R8  R8

6 l 

UE specific Reference Symbols



0

l 



6 l 

even-numbered slots



0

l 



odd-numbered slots

Antenna port 7

6

l 



0

l 



6 l 

even-numbered slots



0

l 



odd-numbered slots

Antenna port 8

6

Technical Details

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Physical Channel Processing – Glossary: Virtual Antenna Port

What is a virtual antenna port?

layers

codewords

Scrambling

Modulation mapper  Layer  mapper 

Scrambling

Modulation mapper 

•

In 3GPP terminology antenna port is a signal transm ission under the identical channel conditions.

•

For each LTE operating mode in the downlink direction f or which an independent channel is assumed, a separate logical antenna port is defined.

•

In order to determine the characteristic channel for an antenna port, a UE must carry out a separate channel estimation for each antenna port. Separate reference signals are sent from each antenna port.

•

In 3GPP standard, each port number has particular purpose. More: LTE568 DL Adaptive CL MIMO (4x2) Network Engineering Information https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D503438182

antenna ports

Resource element mapper 

OFDM signal generation

Resource element mapper 

OFDM signal generation

Precoding

LTE568 uses antenna ports 0, 1, 2 and 3:

Example:

Same Reference Signal from all antennas. UE “sees” 4 TX antennas as 1.

Beamforming vector 

Separate Reference Signal from each antenna. UE “sees” 4 TX antennas

Beamforming (LTE493) uses antenna port 5:

Technical Details

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Mapping of Virtual Antenna Ports 7 & 8 to Physical Antennas

• In NSN, virtual antenna ports 0 and 1 are mapped to separate polarization groups -

2-way TxDiv, 2x2 MIMO transmission schemes possible when beamforming not in use for PDSCH DL control/ broadcast channels also are sent using 2-way TxDiv Are sending Cell-specific Reference Symbols (CRS)

• Virtual antenna ports 7 and 8 are mapped to all 8 antennas -

Used for sending beamformed PDSCH data Are sending DM-RS

4

0 5

1

6

Virtual  Antenna Port 0

2

7

3

Virtual  Antenna Port 1 Virtual  Antenna Port 7, 8

Technical Details

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Antenna Ports 7 & 8 – Dual Layer Transmission

• So where are the virtual antenna ports 7 and 8? •

DM-RS are beamformed together with PDSCH

•  According to 3GPP 36.211, 6.3.4.4 antenna ports 7 and 8 are associated with the respective codewords: u4 u3

CW0

 Antenna Port 7

w11

w12

u2

u1

w1

1

5

2

6

3

7

w5

w2 w21

 Antenna Port 8

w22

CW1 Please note: This virtual antenna port mapping is only valid for Dual Layer transmission.

w6

w3 w7

w4 w8

4

8

From UE perspective, antenna port 7 and antenna port 8 will be “seen” as individual single antennas (although they both use all 8 radiating elements)

Technical Details

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Antenna Ports 7 & 8 – Single Layer Transmission

• So where are the virtual antenna ports 7 and 8? •

For Single Layer transmission, UE data can be either on port 7 or 8

u4 u3

CW0

w 1

w2

u2

u1

w1

1

5

w5

l  / 2

 Antenna Port 7 or 8

2 w2

6

w6

w3

3

7

w7

w4 w8

4

8

For Single Layer transmission the  Antenna Port assignment is fully configurable

Technical Details

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Single Codeword Transmission Using TM8

 According to 3GPP 36.213, 7.1.2.7, single-stream transmission is assumed if one of the transport blocks is disabled: MCS index = 0; redundancy version = 1.

In case one of the transport blocks is disabled, the number of layers equals one; the transport block to codeword mapping is specified according to 36.213, Table 5.3.3.1.5-2: transport block 1

transport block 2

codeword 0 (enabled)

codeword 1 (disabled)

enabled

disabled

transport block 1

-

disabled

enabled

transport block 2

-

and the antenna port for single-antenna port transmission is according to 36.213,Table 5.3.3.1.5B-1: New data indicator of the disabled transport block

Antenna port

0

7

1

8

 Always CW0 for single layer transmission

Full freedom of antenna port selection for single layer transmission

Technical Details

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DCI format used by TM8 • • •

3GPP defines several DL Transmission Modes in 3GPP 36.213 LTE1169 uses TM8 for Multi-User MIMO operation. Do not confuse with TM5 Multi-User MIMO – this TM is not used in NSN

Field

 

Bits

Carrier indicator  Resource allocation header

0 or 3 0 or 1

Resource block assignment

Type 0 Type 1

TM

Scheme

DCI format

TM1 TM2 TM3 TM4 TM5 TM6 TM7

Single-antenna port (p = 0) Transmit diversity Open-loop spatial multiplexing Closed-loop spatial multiplexing Multi-user MIMO Closed-loop rank = 1 precoding Single stream beamforming, port 5

1 1 2A 2 1D 1B 1

TM8

Dual stream beamforming, ports 7 and 8

2B

TPC command for PUCCH HARQ process number Scrambling Identity SRS request Modulation and coding scheme New data indicator Redundancy version Modulation and coding scheme New data indicator Redundancy version

Transport block 1

Transport block 2

Please note: no DL precoding information field.

 N  /  P  /  P   log P  1 DL RB

 N 

DL RB

2

2 3(FDD), 4(TDD) 1 0(FDD), 1(TDD) 5 1 2 5 1 2

Technical Details

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How is TM8-based MU-MIMO done?

•

LTE1169 MU-MIMO uses antenna ports 7 and 8 to multiplex two single-stream UEs

C W0

Data for UE1,  Antenna port 7 DM-RS

C W0

Data for UE2,  Antenna port 8 DM-RS

U 1 =[u1 u 2 u 3 u4 ] 

Beamforming vector for UE1

U 1 =[u1 u 2 u 3 u4 ] 

Since beamforming weights are specific for UE1 and for UE2, two distinctive beams will be formed with UE1 data carried over antenna port 7 and UE2 data over antenna port 8.

UE2 U   ]   2=[u1 u 2 u 3 u4

 Antenna Port 8 beam

UE1

U   2=[u1 u 2 u 3 u4 ]  Beamforming vector for UE2

 Antenna Port 7 beam

Technical Details How is TM8-based MU-MIMO done?

• • •

Multiplexed UEs can share their respective DL resources Freed resources can be distributed to all UEs. This comes at a cost. Multiplexed UEs have their PDSCH transmitted with half of the available power 

Beamformed Beamformed PDSCH PDSCH #1 #1

Beamformed Beamformed PDSCH PDSCH #2 #2

Non-beamformed Non-beamformed PDSCH PDSCH #3 #3

Free resources can be redistributed Before multiplexing Multiplexing frees resources

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Technical Details

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How is TM8-based MU-MIMO done?

• •

MU-MIMO is transparent to the UEs. Multiplexed UE has no knowledge about the presence of the other UE on the other antenna port LTE1169 does not introduce any change over LTE541 in calculation of beamforming weights for the multiplexed UEs. There may be some interference coming from the mutiplexed UEs

NOT IMPLEMENTED IN LTE1169

UE2

UE2 Nulls in TX pattern towards multiplexed UE – due to recalculated beamforming vector 

UE1 Example 1: -12dB interference caused by multiplexed UE2

UE1 Example 2: tm8MuMimoCqiThd are taken into account For each UE pair from step 1 calculate their correlation metric UE pairs are added to the “friend list” “Friend list“ is sorted ascending by the correlation metric UE pairs that fulfill criterion Correlationi,j < tm8MuMimoCorr Thd are eligible for multiplexing *

U H  - Hermitian transpose of U 

Correlation metric between i th and j th UE:

Correlatio ni , j



U i H U  j / U i U  j

U  ,i  U  j  – long term weighting vectors of i th and j th UE Note: long term weighting vectors are wideband (same for all PRBs)

 |U| - Vector norm of U 

* )Pairs cannot have antenna port conflicts, more information coming…

Technical Details UE pair correlation (2/2)

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•

When is correlation metric high and when is it low?

•

Intuitively, U i U  j factor is low when beamforming vectors U i  and U   j  are not similar to each other 

•

From beamforming perspective, this means that beams of i th and j th UE will point in different directions

 H 

U 1 ≠ U  2 Low correlation

U 1 ≈ U   2 High correlation

Technical Details

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Halved Transmit Power for MU-MIMO UE

•

Multiplexed UEs RBGs will receive only half of the available transmit power 

•

However, they will still report same CQI as non-multiplexed UEs in their condition -

CQI report is based on C ell Reference Symbols (CRS)

•

Selected MCS will not match channel conditions. OLLA compensation works too slow, so:

•

eNB compensates reported CQI by -1.59 for the multiplexed RBGs -

•

If only part of RBGs are multiplexed, wideband CQI is re-calculated

Compensated CQI is also used for scheduler decisions (see s cheduler s ecti on of technical details chapter) CQI vs. SNIR for EPA5, real ChanEst

Halved TX power = 3dB loss to SINR

CQI ≈ 0.51*SINR[dB] + 5.3 ] [1 I Q C

Source: 4GMAX simulations

9,6 9,4 9,2 9 8,8 8,6 8,4 8,2 8 7,8 7,6 7,4 7,2 7 6,8 6,6 6,4 6,2 6 5,8 5,6 5,4 5,2 5 4,8 4,6 4,4 4,2 4 3,8 3,6 3,4 3,2 3 2,8 2,6 2,4 2,2 2 1,8 1,6 1,4 1,2 1 0,8 0,6 0,4 0,2 0

CQI = 0.51*SNIR + 5.3

- 9 ,5 - 9 - 8 ,5 - 8 - 7 ,5 - 7 - 6 ,5 - 6 - 5 ,5 - 5 - 4 ,5 - 4 - 3 ,5 - 3 - 2 ,5 - 2 - 1 ,5 - 1 - 0 ,5 0

SNIR [dB]

0,5 1

1,5 2

2,5 3

3,5 4

4,5 5

5,5 6

6,5 7

7,5 8

8,5

Technical Details

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Avoiding virtual antenna Port conflict

•

LTE1169 MU-MIMO UEs are assigned different port numbers (7 and 8)

•  All RBGs belonging to one UE in MU-MIMO mode may be transmitted via one port only •

UEs that have port conflicts will not be multiplexed

Invalid allocation example

Valid allocation example

Technical Details

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Scheduler Impact (1/3)

How to fit UEs to RBGs?

Determination of available resources

Determination of UE pool available for scheduling

Scheduler 

Creation of ranked list of UEs that qualify for scheduling

Time domain scheduling

Determination of resources assigned to UEs

Frequency domain scheduling

Split of resources between bearers within one UE

Congestion detection and handling

Technical Details

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Scheduler Impact (2/3): Determination of RBGs assigned to users

• •

LTE1169 MU MIMO has impact on Frequency Domain Scheduling Frequency Domain Scheduling is divided into two steps: -

Calculation of how many resources allocate to each UE Calculation of which exact resources will be allocated to each UE UE1

For detailed description of MU-MIMO scheduling step, please refer to backup slide #80

UE1

UE1

4 RBGs

4 RBGs UE2

UE3

UE4

  e    l    b   a    l    i   a   v   a   s    G    B    R    7    1

UE2

UE2 2 RBGs

Calculation of number of RBGs per UE

UE3 3 RBGs UE4 5 RBGs

UE5

2 RBGs Calculation of shared MU RBGs and reallocation of freed RBGs

UE3

  s    E    U    d   e   r UE4    i   a    P

3 RBGs freed – reallocated to other UEs

3 MU RBGs 2 SU RBGs

UE5

UE5 3 RBGs

3 RBGs

Technical Details

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Scheduler Impact (3/3): Determination of exact RBGs used by MU-MIMO

• Frequency Domain Scheduling is divided into two steps: -

Calculation of how many resources allocate to each UE Calculation of which exact resources will be allocated to each UE

• FD scheduling can be chosen between: PFSched , TTA and newly introduced  MaxC I  -

Max C/I: Criterion for each UE/RBG is calculated based only on relative channel conditions (CQI) RBG0

RBG1

RBG2

…

RBG16

UE1

M[1,1]

M[1,2]

M[1,3]

…

M[1,16]

UE2

M[2,1]

M[2,2]

M[2,3]

…

M[2,16]

UE3

M[3,1]

M[3,2]

M[3,3]

…

M[3,16]

UE4

M[4,1]

M[4,2]

M[4,3]

…

M[4,16]

UE5

M[5,1]

M[5,2]

M[5,3]

…

M[5,16]

UE3 & 4

M[3&4,1]

M[3&4,2]

M[3&4,3]

…

M[3&4,16]

Table with scheduling criterion for each UE and RBG is created like before LTE1169, and highest criterion is selected for each RBG with restrictions from previous step With MU MIMO added are also rows with criterion for paired UEs. These new criterions are calculated as a sum of two criterions: M[3&4, 1] = M[3,1] + M[4, 1] but using compensated CQI value (see slide #32)

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Interdependencies

Main Menu

There should be some impact, but there is not impact in fact

LTE xxx Limiting feature name

The main feature limits the limiting feature

LTE xxx Supporting feature name

Both features complement each other to boost gains/benefits

Potentially impacted feature name

LTE xxx Minor impact on the main feature, e.g. in some very specific/rare scenarios

Running both features at the same time is problematic

‘main feature supports ‘supporting feature, e.g. gives extra benefits/gains

LTE xxx

Minor impact of the main feature, e.g. in some very specific/rare scenarios

LTE xxx main feature name

‘supporting feature’ supports the main feature, e.g. gives extra benefits/gains

Impacted feature name

The feature is prerequisite for the main feature Both features must be activated together 

LTE xxx

The main feature is prerequisite

Prerequisite feature name

Interdependencies

LTE 496

Main Menu

MU-MIMO users will not be power boosted for its PDSCH. But these two features can be activated both at the same because other users can still be power boosted.

Suppport of QCI 2, 3 and 4

Power Boosting for PDSCH

LTE 541

LTE 1169

Dual Stream Beamforming

TM8 based DL MU MIMO

LTE 1013-b

LTE 31 Link Adaptation by AMC (UL/DL)

LTE 515

TM3/8 Switch LTE1013-b may help LTE1169 by restricting high SINR UEs from becoming multiplexed

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Benefits and Gains

Main Menu

DISCLAIMER: The results of simulations shown in this presentation are examples only. They demonstrate trends (not absolute values) expected after feature activation. The presented simulations should be analyzed with respect to the assumptions taken. They may differ from results achievable in real networks.

Benefits and Gains

Main Menu

System level simulator settings Parameter Name BS Deployment Inter-Site-Distance BandWidth Fading Environment  Angular Spread Pathloss Penetration Number of UEs Traffic Model UL/DL Configuration Special Subframe Configuration FD Scheduling MIMO Switch Mode BeamformingMode FDS AllocationControl CQI Threshold upSM CQI Threshold downDIV TM8 MU CQI Threshold TM8 MU CorrelationThreshold

Value Setting 19 Sites, 3 Sectors per Site 500 meters 10 MHz Typical Urban, 3km/h 5 degree 20 dB 1140 UEs in 57 cells (10 UEs per TTI per cell limit) Full Buffer Traffic Configuration 1 Configuration 5 PFSch, TTA dynamic close loop mimo MU Hybrid beamforming MU-MIMO FDS AllocationControl MU-MIMO (RL35TD) 15dB 10dB -3dB, 0dB, 3dB 0.11, 0.15, 0.25, 0.3, 0.35

Source: System Level Simulation Report https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D504761375

Benefits and Gains

Main Menu

System level simulation – single cell, 2 UEs 1. 2. 3. 4.

For all cases, 2 UEs are in fixed positions For all cases, 2 UEs are configured to use single stream only For all cases, correlation threshold is set to very large value, effectively forcing UEs to MU-MIMO For each case, a specific correlation is achieved by putting them in different positions Correlation 0.0, Correlation 0.1, Correlation 0.2 5. For each case with specific correlation, a specific UE SINR is achieved by setting different loss offset UE SINR: 0dB, 6dB, 12dB, 18dB, 24dB CASE 1

CASE 2

CASE 3

CASE 4

CASE 5

CASE 6

CASE 7

CASE 8

CASE 9

SINR

0

6

12

18

24

0

6

12

18

CORRELATION

0

0

0

0

0

0.1

0.1

0.1

0.1

40 30 20 10 0 -10 -20 -30 -40 -50 -60

CASE 10 CASE 11 CASE 12 CASE 13 24 0 6 12 0.1

0.2

0.2

When there is low correlation between UEs, the MU-MIMO throughput gain is the highest

0.2

MU Cell Capacity Gain (%) 5% User Instasnt Throughput Gain (%)

CASE CASE CASE CASE CASE CASE CASE CASE CASE CASE CASE CASE CASE 1 2 3 4 5 6 7 8 9 10 11 12 13

When there is high correlation between UEs, MU-MIMO causes throughput loss. The higher the SINR of multiplexed UEs, the bigger the loss.

Benefits and Gains

Main Menu

System level simulation – 57 cells and 1140 UEs

• • •

57 cells, 1140 UEs, Proportional Fair (PFSched) scheduling algorithm Up to 8.6% gain on average, 63% on cell edge throughput Performance degradation past correlation threshold 0.25

SU-case

CASE1

CASE2

Correlation thresholdSINR threshold

 

0.15

0.25

0.3

0

0

0

0

8339

8000

 

8902

CASE4

0.11

10000

CASE3

 

8978

9058

 

8868

Corresponds to tm8MuMimoCqiThd

+8.62%

6000 Cell Throughput 4000

Cell Coverage

+63.3%

2000 170.2

249

261

 

278

273

0 SU-case

CASE1

CASE2

CASE3

CASE4

≈5

Benefits and Gains

Main Menu

System level simulation – 57 cells and 1140 UEs

• • •

57 cells, 1140 UEs, Throughput To Average (TTA) scheduling algorithm Up to 11% gain on average, 24% on cell edge throughput Performance degradation past correlation threshold 0.15 SU-case

CASE1

Correlation thresholdSINR threshold

CASE2

CASE3

CASE4

0.11

0.15

0.25

0.3

0

0

0

0

-

10000 9000

  8883 8743 +10.8%

 

8848

 

Corresponds to tm8MuMimoCqiThd

8827

≈5

8017

8000

7000 6000 5000

Cell throughput

4000

5% user instant throughput

3000

2000 1000

203.4

 

233.9

 

243.5

 

249.1

251.8 +23.8%

0 SU-case

CASE1

CASE2

CASE3

CASE4

Benefits and Gains FiVe findings • • •

Main Menu

Stationary test 2 UES placed in different positions with similar SINR and different correlation correlation between UEs measured at the eNB MU-MIMO throuhgput gain 30%

Conclusions: 





UE correlation is key factor to feature gain The higher SINR, the lower correlation required to achieve gain Trend is consistent with simulation

5.75%

10%

 

9.05% 0%

-10% -16%

-30% -50% -57%

-70%

-64% -73%

-90% 1 5d B/ 0. 82

Source: FiVe report https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D503850648

1 5d B/ 0. 65

1 0d B/ 0. 37

SINR

1 0d B/ 0. 19

1 0d B/ 0. 12

5 dB /0 .1 9

correlation

5 dB /0 .1 6

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Deployment Aspects

Main Menu

• Feature LTE1169 (TM8 based DL MU MIMO) is activated on cell level • • • •

LNCEL-actTm8MuMimo must be set to true LNCEL- tm8MuMimoC qiThd  must be configured (default is 3) LNCEL- tm8MuMimoCorrThd  must be configured (default is 0.15)  Activating and deactivating feature requires BTS restart

• Relation to other features • LNCEL-dlMimoMode must be set to ‘Dual Stream Beamforming (60)’ - LTE541 Dual Stream Beamforming required • LNBTS-actEnhAcAndGbrServices must be true - LTE496 Support for QCI 2, 3, 4 required • LNCEL-dlamcE nable must be true - LTE31 Link Adaptation by AMC (UL/DL) required

Configuration Management

Main Menu

• Definition of terms and rules for parameter classification* The ‘Basic Parameters’ category contains primary parameters which should be considered during cell deployment and must be adjusted to a particular scenario. These are: > Network Element (NE) identifiers > Planning parameters, e.g. neighbour definitions, frequency, scrambling codes, PCI, RA preambles > Parameters that are the outcome fr om dimensioning, i.e. basic parameters defining amount of resources > Basic parameters activating basic functionalities, e.g. power control, admission control, handovers > Parameters defining operators’ strategy, e.g. traffic steering, thresholds for power control, handovers, cell reselections, basic parameters defining feature behaviour 

The ‘Advanced Parameters’ category contains the parameters for network optimisation and fine tuning: > Decent network performance should be achieved without tuning these parameters > Universal defaults ensuring decent network performance need to be defined for all parameters of this category. If this is not possible for a given parameter it must be put to the ‘Basic Parameters’ category > Parameters requiring detailed system knowledge and broad experience unless rules for the ‘Basic Parameters’ category are violated >  All parameters (even without defaults) related to advanced and very complex features

* - purpose: categories of parameters have been defined to simplify network parameterization. Parameterization effort shall be focused mainly on parameters included in basic category. Categorization will be reflected in a ‘view’ definition in NetAct CM Editor (plann ed in RL60) i.e. parameters will be displayed according to the category: either in the ‘Basic parameters’ view or the ‘Advanced parameters’ view.

Configuration Management

Main Menu

• New parameter  actTm8MuMimo

Activate TM8 MU-MIMO

Object:

LNCEL

Range:

[true, false]

Step:

-

Default:

false

Multiplicity:

1

Unit:

boolean

Category:

Basic

Parameter to activate or deactivate TM8 MU-MIMO in a cell

Configuration Management

Main Menu

• New parameter  tm8MuMimoParSet

TM8 MU-MIMO parameter set

Object:

LNCEL

Parameter Set for TM8 MU-MIMO.

Range:

structure

Step:

-

If actTm8MuMimo is set to 'true' tm8MuMimoParSet mandatory required.

Default:

-

Multiplicity:

-

Unit:

-

Category:

 Advanced

Contains parameter: tm8MuMimoCorrThd tm8MuMimoCqiThd

Configuration Management

Main Menu

• New parameter  tm8MuMimoCqiThd

TM8 MU-MIMO CQI threshold

Object:

LNCEL

Range:

0..16

The CQI threshold above which the TM8 BF UE can be selected as TM8 MU-MIMO candidate. This TM8 MU-MIMO candidate must also be rank 1 UE.

Step:

0.1

Default:

3

Multiplicity:

1

Unit:

number 

Category:

 Advanced

Configuration Management

Main Menu

• New parameter  tm8MuMimoCorrThd

TM8 MU-MIMO correlation threshold

Object:

LNCEL

Range:

0..1

The correlation threshold below which two TM8 MU-MIMO candidate can be paired.

Step:

0.01

Default:

0.15

Multiplicity:

1

Unit:

number 

Category:

 Advanced

Configuration Management

Main Menu

• Modified parameter  dlsFdAlg

DL scheduler FD algorithm

Object:

LNCEL

Range:

TTA (0), PFsch (1), MaxCI (2)

Step:

-

Default:

PFsch

Multiplicity:

1

Unit:

enum

Category:

Basic

Parameter to choose between different available algorithms for frequency domain scheduling.  Available algorithms are: TTA: fair allocation property based on ratio of relative to wideband channel quality PFsch: proportional fair allocation property based on ratio of immediate to average scheduled channel quality MaxCI: Maximum C/I based sub-band channel quality

MaxCI algorithm introduced with LTE1169

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Deployment Aspects Where to deploy the feature?

Main Menu

• Feature can be activated only with LTE541 Dual Stream Beamforming feature enabled -

8-pipe configurations

-

Quad X-pol antennas

• Cells with high load • Clusters with bad radio condition • Clusters with high interference level • Cells with good radio DL conditions should be avoided, as no gain (and possibly loss) is expected for high DL SINR UEs

Deployment Aspects

Main Menu

Known (or suspected) issues

•

High SINR UEs experience serious throughput degradation when multiplexed

•

This was proven by FiVe test and simulations

•

No designated threshold to limit MU-MIMO for high CQIs. Single Layer UEs with high CQI can still be multiplexed.

•

Change Request CRL0815 has been issued about this fact but will be implemented in LTE1787 “TM9 with 8TX MU -MIMO and Up to 2 Layers Overall” in RL55 TP degradation for UEs multiplexed      k     n in good SINR conditions. FiVe test     a      R show degradation starts at 12dB with     o Single     m default tm8MuMimoCorrThd       i Layer BF Dual Layer BF     m setting. That corresponds to reported CQI=11.5   p    U    h    T    k   n   a    R    f    b

MU-MIMO/Single/Dual Layer BF   n   w   o    D    h    T    i    R    f    b

MU-MIMO/ Single Layer BF

mimoCqi  tm8MuMimoCqiThd

bfCqiThDown

bfCqiThUp

Effectively throughput on cell level can be degraded. Multiplexing gain from bad SINR UEs may not compensate loss from good SINR UEs!

Deployment Aspects

Main Menu

Known (or suspected) issues

• •

MU-MIMO can be limited in high SINR regions by activating “ beamforming fallback” MU-MIMO UE or single-layer UE will be reconfigured to use 2-way Tx Diversity in high SINR/CQI

•  Alternatively, LTE1013-b “TM3/8 switch” feature can be used to suppress MU-MIMO in high SINR

  p    U    h    T    k   n   a    R    f    b

     k     n     a      R     o     m      i     m

LNCEL-actBfFallback  must be set to true Single Layer BF

Dual Layer BF

MU-MIMO/Single/Dual Layer BF   n   w   o    D    h    T    i    R    f    b

MU-MIMO/ Single Layer BF

  e    l   g   /    O   n   F   M    i    B    S    I    /   r   e   M     v    i   y   U   a    D   L   x    M    T

TxDiv

This is a workaround. mimoBfslCqiThD and mimoBfslCqiThU may need to be further optimized with LTE1169

mimoCqi  tm8MuMimoCqiThd

bfCqiThDown

bfCqiThUp

mimoBfslCqiThD

mimoBfslCqiThU

Deployment Aspects

Main Menu

How to select the field trial area?

PDSCH MCS Usage Counters:

• Most gains from LTE1169 in terms of DL throughput increase are experienced byUEs at the cell edge

• These can be identified as contributors to the low MCS index usage (cell edge UEs are likely to be using more robust codecs). • Moreover, there is risk that UEs with very good radio conditions but using Single Stream transmission will be multiplexed, as there is no designated upper CQI limit for MUMIMO multiplexing. Such high-CQI users when multiplexed will show high loss in throughput. They can be found among contributors of high MCS index usage.

• Monitor PDSCH transmission counters using given MCS. Select cluster with thehighest ratio of robust codec transmissions and lowest ratio of high yield codec transmissions

• LTE_393b K PI “Percentage of DL Traffic Volume using Low MCS codes” can be used to monitor share of low order MCS • LTE_394b KPI “Percentage of DL Traffic Volume using High MCS codes” can be used to monitor share of high order MCS

M8001C45 M8001C46 M8001C47 M8001C48 M8001C49 M8001C50 M8001C51 M8001C52 M8001C53 M8001C54 M8001C55 M8001C56 M8001C57 M8001C58 M8001C59 M8001C60 M8001C61 M8001C62 M8001C63 M8001C64 M8001C65 M8001C66 M8001C67 M8001C68 M8001C69 M8001C70 M8001C71 M8001C72 M8001C73

PDSCH_TRANS_USING_MCS0 PDSCH_TRANS_USING_MCS1 PDSCH_TRANS_USING_MCS2 PDSCH_TRANS_USING_MCS3 PDSCH_TRANS_USING_MCS4 PDSCH_TRANS_USING_MCS5 PDSCH_TRANS_USING_MCS6 PDSCH_TRANS_USING_MCS7 PDSCH_TRANS_USING_MCS8 PDSCH_TRANS_USING_MCS9 PDSCH_TRANS_USING_MCS10 PDSCH_TRANS_USING_MCS11 PDSCH_TRANS_USING_MCS12 PDSCH_TRANS_USING_MCS13 PDSCH_TRANS_USING_MCS14 PDSCH_TRANS_USING_MCS15 PDSCH_TRANS_USING_MCS16 PDSCH_TRANS_USING_MCS17 PDSCH_TRANS_USI NG_MCS18 PDSCH_TRANS_USING_MCS19 PDSCH_TRANS_USING_MCS20 PDSCH_TRANS_USING_MCS21 PDSCH_TRANS_USING_MCS22 PDSCH_TRANS_USING_MCS23 PDSCH_TRANS_USING_MCS24 PDSCH_TRANS_USING_MCS25 PDSCH_TRANS_USING_MCS26 PDSCH_TRANS_USI NG_MCS27 PDSCH_TRANS_USING_MCS28

Technical Details

Main Menu

Supported Configurations Example

- Configuration example (L): 1+1+1 @ 8TX/8RX (BW up to 20MHz) Sector1 LCR1 Tx1Rx1

FZHA/ FZHE

Sector1 LCR1 Tx2Rx2

Sector1 LCR1 Tx3Rx3

Sector1 LCR1 Tx4Rx4

Sector1

Sector1 LCR1 Tx5Rx5

Sector1 LCR1 Tx6Rx6

Sector1 LCR1 Tx7Rx7

Sector1 LCR1 Tx8Rx8

Sectors 2 and 3 antenna connections/LCRs are equivalent as in sector 1

Calibration port

Sector2

Sector3

Example from R L35 B TS S ite S olutions NE I:

FSM3

https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D498693691

 All of the RL35 supported HW configurations are found in “TD LTE BTS Supported Configurations”  https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/406750073

Deployment Aspects How to configure

• •

Cell must be 8-pipe Choose “Dual Stream Beamforming” for MIMO mode

TM8 Dual Stream Beamforming

FZNC: 5/10W FZHA: 5/10W FZHE: 5/10/15W

•

Further steps assume that LTE541 Dual Stream Beamforming is properly configured

Main Menu

Deployment Aspects How to configure  Activate TM8 MU-MIMO flag • LNCEL-actTm8MuMimo must be set to true •

Please note: parameter is found in Pack et S cheduler C ontrol functional group

 Activating and deactivating LTE1169 feature requires BTS restart

Main Menu

Deployment Aspects How to configure Set TM8 MU-MIMO CQI and correlation thresholds • LNCEL- tm8MuMimoCqiT hd must be configured (default is 3) • LNCEL- tm8MuMimoCorrT hd must be configured (default is 0.15) •

Please note: parameters can be accessed by creating TM8 MU-MIMO parameter set in the LNCEL object

Main Menu

Deployment Aspects How to configure

Main Menu

 Activate enhanced AC and GBR services • LNBTS-actEnhAcAndGbrServices must be true •

This parameter activates support of the following features - ARP based Admission Control (LTE534) - Smart Admission Control, comprising RAC and TAC (LTE497) LTE1169 prerequisite - EPS bearers with QCI 2, 3 and 4 (LTE496). • Feature LTE496 introduces support of QCI 2, 3, and 4 along with higher guaranteed bit rates and related congestion detection and handling mechanisms.

Deployment Aspects How to configure Enable Downlink Adaptive Modulation and Coding (DL AMC) • LNCEL-dlamcEnable must be true • LTE31 Link Adaptation by AMC (UL/DL) required

Main Menu

Deployment Aspects How to configure If Beamforming Fallback is needed • LNCEL-actBfFallback  must be true • LNCEL-actTmSwitch must be false • LNCEL-mimoBfslCqiThD and LNCEL-mimoBfslCqiThU must be configured

Main Menu

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Dimensioning Aspects

Main Menu

•

LTE1169 does not impact cell coverage. UEs that are on the cell edge will likely have CQI below tm8MuMimoCqiThD, and will be scheduled using TM8 single layer transmission mode

•

LTE1169 impacts capacity. In the RANDim tool this can be modeled by entering expected capacity gain in “Additional Capacity Gain” field. 10% capacity gain was obtained with help of system level simulations

•

In real network scenarios, and under different parameter settings gain figures may differ  Phase 1

DL Inter Site Distance [km] Channel model Cell Load [%] MIMO Settings Frequency scheduler OTDOA Increased UL MCS range Victim Cell Fully Loaded Deployment class DL-to-UL configuration Special Subframe Format DL/UL Ratio [%] Cyclic Prefix Number of PDCCH Symbols per Subframe  Additional capacity gain [%] Cell Throughput [kbps]

Phase 2

UL

0.46 SCME Urban Macro NLOS 50.00% 50.00% 8Tx DS-HBF Mode 8 8Rx MRC Channel aware Channel aware FALSE FALSE TRUE Outdoor-to-Indoor Basic&Mature DL-to-UL Conf 1 "S" Subframe Format 5 44.29% 40.00% Normal 3 PDCCH symbols 0.00% 0.00% 30561.06

13813.70

DL

UL 0.46 SCME Urban Macro NLOS 50.00% 50.00% 8Tx DS-HBF Mode 8 8Rx MRC Channel aware Channel aware FALSE FALSE TRUE Outdoor-to-Indoor Basic&Mature DL-to-UL Conf 1 "S" Subframe Format 5 44.29% 40.00% Normal 3 PDCCH symbols 10.00% 0.00% 33617.16

13813.70

Newest version of the RAN Dim tool can be found here

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Energy Savings Aspects

•

No significant energy saving gain with LTE1169 feature

•

10% gain in cell throughput could translate to lower required site density, but in most cases network is UL limited

•

No impact expected on cell coverage, as the very cell edge is expected to use Single Layer beamforming due to MU-MIMO CQI threshold

Main Menu

  p    U    h    T    k   n   a    R    f    b

     k     n     a      R     o     m      i     m

Single Layer BF

Dual Layer BF

MU-MIMO/Single/Dual Layer BF   n   w   o    D    h    T    i    R    f    b

MU-MIMO/ Single Layer BF

  e    l   g   /    O   n   F   M    i    B    S  r   I    /   e   M   v   y      i   a   U    D   x   L   M    T

TxDiv

mimoCqi 

Single Layer @ cell edge expected

tm8MuMimoCqiThd

bfCqiThDown

bfCqiThUp

LTE1169 – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuration Examples, Fault Mgmt, Trial Area

Performance Aspects

Main Menu

New counters

Counter name

Description

TM8_DUAL_USER_SINGLE_BF_MODE (M8010C66)

This counter provides the number of PDSCH transmissions in dual-user singlestream stream beamforming beamforming mode in TM8.

LTE_Pwr_and_Qual_DL

Trigger event: The counter is incremented on each PDSCH transmission with dualuser single-stream beamforming mode in TM8. Use case: Can be used to monitor if the LTE1169 LTE1169 feature is working. When coupled with TM8_SINGLE_BF_MODE, it can be used to measure the ratio of multiplexed pairs to non-multiplexed pairs. Tm8MuMimoPairRatio=100% Tm8MuMimoPairRatio=100% * TM8_DUAL_USER_SIN TM8_DUAL_USER_SINGLE_BF_MODE GLE_BF_MODE / TM8_SINGLE_BF_MODE  Please note that neither this counter nor the proposed KPI provide information about the ratio of multiplexed multiplexed RBGs. RBGs.

Performance Aspects

Main Menu

Feature monitoring

Feature impact

How to measure

DL throughput

KPIs:

Mean DL throughput should increase after LTE1169 activation. According According to simulations, up to 10% average throughput throughput increase increase is expected expected

- DL RLC PDU volume transmitted ( LTE_284a LTE_284a ) - Average  Average PDCP Layer Active Cell Throughput DL DL ( LTE_5292b LTE_5292b ) Counters:

- RLC_PDU_VOL_TRAN RLC_PDU_VOL_TRANSMITTED SMITTED (M8012C18) - PDCP_DATA_RATE_MEAN_DL (M8012C26)

Performance Aspects

Main Menu

Feature monitoring

Feature impact

How to measure

MCS distribution

KPIs:

- Percentage of DL Traffic Volume using Low MCS codes DL MCS for multiplexed UEs is expected to decrease, decrease, since they get their PDSCH data with reduced transmit power and compensated CQI (see slide 30 for explanation). This will impact the MCS distribution by shifting it towards lower MCS values. Percentage of DL Traffic Volume using Low MCS codes (LTE_393b LTE_393b)) is expected to increase after LTE1169 LTE1169 feature activation.

( LTE_393b LTE_393b ) Counters:

- PDSCH_TRANS_USING_MCS0 (M8001C45)… - PDSCH_TRANS_USING_MCS28 (M8001C73)

LTE1169 – LTE1169  – TM8 based DL MU-MIMO

Main Menu

Introduction

Dimensioning Aspects

Motivation and Feature Overview

Dimensioning Impacts and Examples

Technical Details

Energy Savings Aspects

Functionality and Implementation, Message Flows

Energy Savings Examples and Calculations

Interdependencies

Performance Aspects

Interdependencies with other features and functions

Counters and KPIs, Feature Impact Analysis and Verification

Benefits and Gains

Compliance Aspects

Simulation, Lab and Field Findings

3GPP, IETF, ETSI

Configuration Management Parameters and Parameterization Scenarios

Deployment Aspects  Activation, Configuratio Configuration n Examples, Examples, Fault Mgmt, Trial Trial Area

Compliance Aspects

• Rel-9 compliant UEs are required for LTE1169 • Rel-8 UEs will be scheduled using single stream beamforming (TM7) • Class 1 UEs will be scheduled using TxDiv (TM2)

Main Menu

References

Reference LTE1169 CFAM Design and Experimental Evaluation of Multi-User Beamforming in Wireless LANs Ehsan Aryafar, Narendra Anand, Theodoros Salonidis, Edward W. Knightly 

LTE-Advanced Air Interface Technology  Xincheng Zhang, Xiaojin Zhou, Auerbach Publications © 2013 RL35 BTS Site Solutions NEI https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D498693691 Network Engineering Information - RL30 & RL25TD - Radio - RRM Scheduler (2) https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D440522952

System Level Simulation Report https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D504761375 FiVe report https://sharenet-ims.inside.nokiasiemensnetworks.com/Overview/D503850648

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Abbreviations

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BF

Beamforming

MU

Multi User

BLER

Block Error Rate

PDCCH

Physical Downlink Control Channel

CQI

Channel Quality Indicator

PDSCH

Physical Downlink Shared Channel

DM-RS

Demodulation Reference Signal

RBG

Resource Block Group

EV

Eigenvector

SINR

Signal to Interference plus Noise ratio

FSMr3

Flexi System Module rel. 3

SRS

Sounding Reference Signal

MCS

Modulation and Coding Scheme

TM

Transmission Mode

BF

Beamforming

 X H (upper index H)

Hermitian operator (conjugate transpose)

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Scheduler Impact: Determination of number of MU-MIMO RBGs

•  After determination of required resources done by Frequency Domain Allocation Control, LTE1169 will calculate MU RBGs to free some resources and reallocate them to another UEs • This is done in several steps: - In first step only retransmitting MU UEs are considered •

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If 2 retransmitting UEs can be paired, number of MU RBGs each UE can provide is calculated and minimum of two UEs is taken to determine number of MU RBGs for these UEs.

In second step MU UEs with first transmission are considered. If retransmitting UEs still have some MU RBGs they can share, new transmit UEs will firstly try to pair with them, and then with another new transmit UE Number of RBGs which retransmitting UE can provide and number of RBGs that 1st transmit UE need are calculated

Number of needed MU RBGs is calculated for first and second UE

If number of MU RBGs that first UE needs is smaller then for second UE

If number of RBGs that 1st transmit UE need is smaller than number of RBGs that retransmitting UE can provide: YES 1st

 All transmit UE RBGs will be MU RBGs. Number of RBGs that retransmitting UEs still can provide is calculated

-

NO 1st

Number of SU RBGs that transmit UE will still need is calculated

 All first UE RBGs will be MU RBGs. Number of SU RBGs that second UE will still need is calculated

In last step freed RBGs are reassigned to another demanding UEs • •

UEs for reassignment are chosen in order of Time Domain sc heduling metric. If UE has still som e data, is MU and have paired UE also with data in buffer, freed RBGs are allocated to them as MU RBGs, else SU RBGs are allocated only to primary UE. This is done until there are still som e RBGs left