Key Issues of 3GPP LTE-Advanced - krnet.or.krB9... · Key Issues of 3GPP LTE-Advanced June 21th, 2010 ... It includes work on both 2nd and 4th generation technologies. ... (MIMO,

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Key Issues of 3GPP LTE-Advanced

June 21th, 2010

Sungho Moon

([email protected])

4G Technical Research Gr. MCTRL

mailto:[email protected]

Great Company Great PeopleGreat Company Great People

Contents

3GPP standard history and activity

Key issues in LTE-Advanced (especially for release-10 time frame)• Carrier aggregation

• Relay

• DL MIMO enhancement

• UL MIMO enhancement

References

2


3GPP Standard History and Activity

Great Company Great People

Evolution Path in Standardization toward IMT-A

4

*LTE : Long Term Evolution

*UMB:Ultra Mobile Broadband

*IW: Inter-working

1G 2G

High

(Up to 350 Km/h)

Medium

(Vehicular)

Low

(Nomadic)

Peak Data Rate14.4 Kbps 144 Kbps 384 Kbps ~ 50 Mbps ~100 Mbps

CDMA

GSMAMPS

W-CDMA

HSDPA/HSUPA

CDMA2000/Ev-DV/DO

1995 2000 2005 2010

WiBro/M-WiMAX

IEEE

802.16e

IEEE

802.11a/b

802.16 a/d

Mobility

3G

IEEE

802.11n

Radio Link >100 Mbps (high mobility)

~1GHz (Fixed, Nomadic)

High Spectral efficiency

( 5~10 bps/Hz)

Heterogeneous Network

Cost-effectiveness Higher capacity & coverage

IMT-Advanced

Standard

~1 Gbps

3G Ev.IEEE

802.20

LTE*

UMB*

WLAN

F-WiMAX

MBWA

IEE 802.11

VHT

IEEE

802.16m

LTE-A


3GPP – the Partnership

3GPP stands for 3rd Generation Partnership Project*.

The partners are standards developing organizations:

Contribution driven … companies participate in 3GPP through their membership of one of these “Organizational partners”

Currently over 350 individual members (Operators, Vendors, Regulators)

13 Market representation partners (giving perspectives on market needs and drivers)

5

* 3GPP is not constrained to 3rd Generation. It includes work on both 2nd and 4th generation technologies.


3GPP – the Work

Approximately 185 meetings per year

Many co-located meetings, totaling around 600 delegates

Some meetings receive 1000 documents

6


Release of 3GPP Specification

7

1999 2000 2001 2002 2003 2004 2005

Release 99

Release 4

Release 5

Release 6

1.28Mcps TDD

HSDPA, IMS

W-CDMA

HSUPA, MBMS, IMS+

2006 2007 2008 2009

Release 7 HSPA+ (MIMO, HOM etc.)

Release 8

2010 2011

LTE, SAEITU-R M.1457

IMT-2000 Recommendations

Release 9

LTE-AdvancedRelease 10

GSM/GPRS/EDGE enhancements

Small LTE/SAE enhancements


Timelines for LTE-Advanced

LTE-Advanced

“3GPP submission for the ITU’s IMT-Advanced system”

8

Key Timeline for LTE-A Date

Study Item, “LTE-Advanced” approved in 3GPP Mar. 2008

LTE-Advanced Requirements (TR. 36.913) Jun. 2008

LTE-Advanced “Early Submission” made to ITU-R Sep. 2008

“Complete Technology Submission” to ITU-R Jun. 2009

“Final Submission” to ITU-R Oct. 2009

Completion of LTE-Advanced specification by 3GPP 2010/2011


System Requirements of LTE-A

Requirement 3GPP LTE-A 3GPP LTE

C-Plane Latency (Dormant <-> Active)

Less than 10 ms Less than 50 ms

C-Plane Latency (Idle <-> Active)

50 ms 100 ms

U-Plane Latency Less than Rel-8 Less than 5 ms

Peak Data Rate DL: 30bps, UL: 15bps DL: 5bps, UL: 2.5bps

Average Spectrum Efficiency

DL: 2.4(2x2),2.6(4x2),3.7(4x4)UL: 1.2(1x2),2.0(2x4)

DL: 3~4 times of Rel6 HSDPA (2x2)UL: 2~3 times of Rel6 Enhanced UL (1x2)

Cell-Edge Spectrum Efficiency

DL: 0.07(2x2),0.09(4x2),0.12(4x4)UL: 0.04(1x2),0.07(2x4)

DL: 3~4 times of Rel6 HSDPA (2x2)UL: 2~3 times of Rel6 Enhanced UL (1x2)

CoverageSame as LTE Up to 5Km: Optimized

Up to 30Km: Slight degradationUp to 100Km: Functional

Mobility

Support up to 350Km/h, possibly 500Km/h depending frequency

Up to 10Km/h: Further enhancementHigh speed: No degradation or better

Up to 15Km/h: OptimizedUp to 120Km/h: High performance

Up to 350Km/h (or 500Km/h): Functional

VoIPBetter than LTE Case 1: 317(DL)/241(UL)

Case 3: 289(DL)/123(UL)

9


Carrier Aggregation(Bandwidth Extension)


Objectives of Carrier Aggregation

Wider bandwidth transmission using carrier aggregation Entire system bandwidth up to, e.g., 100 MHz, comprises multiple basic

frequency blocks called component carriers (CCs) Satisfy requirements for peak data rate

Each CC can (not) be backward compatible with Rel. 8 LTEMaintain backward compatibility with Rel. 8 LTE

Carrier aggregation supports both contiguous and non-contiguous spectrums, and asymmetric bandwidth for FDD Achieve flexible spectrum usage

Frequency

System bandwidth,

e.g., 100 MHzCC, e.g., 20 MHz

UE capabilities

• 100-MHz case

• 40-MHz case

• 20-MHz case

(Rel. 8 LTE)


Basic Principles in LTE-A Rel-10 CA

Component carrier aggregation numerology

Re-use of LTE Release numerology up to 100 (or 110) RBs on a component carrier

Spectrum utilization, guard bands component carrier spacing

RAN4 study for the needed frequency spacing between the contiguous component carriers for contiguous carrier aggregation

Carrier center frequency positioning considering frequency raster of 100kHz

Need of guard subcarrier and its relevant special carrier adapting legacy LTE system BW

Non-contiguous carrier aggregation

Baseline assumption of the same methodology in development for contiguous and non-contiguous aggregation

No UL heavy scenarios

No support for the larger number of UL CCs than DL CCs


Downlink Multiplexing Scheme

One transport block (TB), which corresponds to a channel coding block and a retransmission unit, is mapped within one CC

Parallel-type transmission for multi-CC transmission

• Good affinity to Rel. 8 LTE specifications

Mod.

Mapping

Channelcoding

HARQ

Mod.

Mapping

Channelcoding

HARQ

Mod.

Mapping

Channelcoding

HARQ

Mod.

Mapping

Channelcoding

HARQ

Transport

block

Transport

block

Transport

block

Transport

block

CC

Downlink: OFDMA with component carrier (CC) based structure

Priority given to reusing Rel. 8 specification for low-cost and fast development


Uplink Multiple Access Scheme

Uplink: N-times DFT-Spread OFDM

Achieve wider bandwidth by adopting parallel multi-CC transmission

Satisfy requirements for peak data rate while maintaining backward compatibility

Low-cost and fast development by reusing Rel. 8 specification

“N-times DFT-Spread OFDM”

CC

Freq.

CC

Parallel Rel. 8 LTE transmission

PUCCH region

PUSCH(Physical uplink shared channel)


Carrier Aggregation Scenarios Proposed by RAN4

Inter-band non-contiguous CA Region 1

» 40 MHz UL/DL: 20 MHz CC (Band 7) + 20 MHz CC (Band 20), FDD


» 40 MHz UL/DL: 20 MHz (Band 7) + 20 MHz CC (Band 3), FDD

Region 2

» 20MHz UL/DL: 10 MHz CC (Band 5) + 10 MHz CC (Band 12), FDD

» 10MHz UL/DL:5MHz CC (Band 17) + 5MHz CC (Band 4), FDD



» 20MHz UL/DL:10MHz CC (Band 2) + 10 MHz CC (Band 4), FDD


Region 3



» 40MHz UL/DL: 20 MHz CC (Band 38) + 20 MHz CC (Band 40), TDD



» 15 MHz UL/DL: 5 MHz CC (Band 1) + 10 MHz CC (Band 8), FDD 15

Intra-band non-contiguous CA FDD: None

TDD: None

Intra-band contiguous CA FDD: UL: 40 MHz, DL: 40 MHz in Band 7 (2600 MHz)

TDD: UL/DL: 50 MHz in Band 40 (2300 MHz)

TDD: UL/DL: 40 MHz in Band 38 (2600 MHz)

Proposed by Korean

operators & vendors

For CA deployment study

in Rel-10 time frame

&

For early LTE-A deployment, with these, LTE-A RF

requirement will be treated.

Ref: R4-101062, NTT DOCOMO, et. al.


Carrier Aggregation Scenario Approved in RAN

Intra-band contiguous CA

Inter-band non-contiguous CA

Specification of carrier aggregation shall be done in Release independent manner.

TBD bandwidth will be finally decided after having RAN4 discussion Not clear whether it should be 40MHz or 50MHz

16

E-UTRA

CA Band

E-UTRA

operating

Band

Uplink (UL) band Downlink (DL) band

Duplex

modeUE transmit / BS receive Channel

BW MHz

UE receive / BS transmit Channel

BW MHzFUL_low (MHz) – FUL_high (MHz) FDL_low (MHz) – FDL_high (MHz)

CA_40 40 2300 – 2400 [TBD] 2300 – 2400 [TBD] TDD

CA_1 1 1920 – 1980 [TBD] 2110 – 2170 [TBD] FDD

E-UTRA

CA Band

E-UTRA

operating

Band

Uplink (UL) band Downlink (DL) band

Duplex

modeUE transmit / BS receive

Channel

BW MHz

UE receive / BS transmitChannel

BW MHzFUL_low (MHz) – FUL_high (MHz) FDL_low (MHz) – FDL_high (MHz)

CA_1-5

1 1920 – 1980 [TBD] 2110 – 2170 [TBD]

FDD

5824 – 849 [TBD] 869 – 894 [TBD]

Ref: RP-100358


Component Carrier Types

Backwards compatible carrier:

A carrier accessible to UEs of all existing LTE releases.

Can be operated as a single carrier (stand-alone) or as a part of carrier aggregation.

For FDD, a backwards compatible carriers always occur in pairs, DL and UL.

[Non-backwards compatible carrier]:

A carrier not accessible to UEs of earlier LTE releases, but accessible to UEs of the release defining such a carrier.

Can be operated as a single carrier (stand-alone) if the non-backwards compatibility originates from the duplex distance, or otherwise as a part of carrier aggregation.

Following additional carrier Types could be considered for Rel-11 or future release:

[Extension carrier]:

If specified, a carrier that cannot be operated as a single carrier (stand-alone), but must be a part of a component carrier set where at least one of the carriers in the set is a stand-alone-capable carrier.

- The sum of backward compatible component carrier and extension carrier can be more than 110 RBs.

Segment 1

Segment 2

BB0

Re

l-8

co

mp

atib

le

Carrier 0

PD

CC

H

Ref: R1-094203 Qualcomm Europe

[Carrier segment]:

Carrier segments, if specified, are defined as the bandwidth extensions of a Rel-8 compatible component carrier (<110RBs) and constitute a mechanism to fully utilize frequency resources in an efficient and backwards compatible way complementing carrier aggregation means.

- The sum of backward compatible component carrier and carrier segment(s) shall be no more than 110RBs.


LTE-A UE Tx/Rx Separation

Default Tx-Rx RF carrier separation for LTE Rel-8 UEs

Non-backward compatibility of other Tx-Rx carrier separation

Support of flexible DL/UL carrier combination from Rel-8 RRC signaling

Ref: TS36.101

Ref: R1-091363 Nokia, Nokia Siemens Networks


Carrier Assignment and Anchor CCs

DL/UL component carrier assignment

Configured to an LTE-A UE by UE-specific dedicated signaling

UE-specific DL active CC set

The set of DL component carriers configured by dedicated signaling on which a UE may be scheduled to receive the PDSCH in the DL.

UE-specific UL active CC set

The set of UL component carriers on which a UE may be scheduled to transmit the PUSCH in the UL.

DL/UL anchor CCs (Primary CC)

A PCC concept, which is the set of component carriers on which all control signaling is transmitted to/from a UE, is introduced in Rel-10 CA

The UL PCC and DL PCC are configured per UE.

The UL PCC is used for transmission of L1 uplink control information.

The DL PCC cannot be de-activated.

Re-establishment will be triggered when the DL PCC experiences RLF, not when other DL CC’s experience RLF.

System information

Configured CC’s which are not the PCC are called the Secondary CC’s (SCC)

Dedicated signaling can be used to provide the UE about relevant system information SCC’s.


PDCCH Transmission

PDCCH transmission and blind decoding

Separately coded PDCCH per PDSCH on multiple DL component carriers

Cross-carrier scheduling and blind decoding

PDCCH on a component carrier can assign PDSCH or PUSCH resources in one of multiple component carriers using the carrier indicator field

- 3 bit carrier indicator field in DCI format with fixed position- UE-specific RRC configured indexing but details are FFS.

PDCCH region

PDSCH region

Frequency

Time CC1 CC2 CC3

SS for PDSCH CC1 SS for PDSCH CC2 SS for PDSCH CC3

a)

Ref : R1-102015, Panasonic


Association between PDCCH and PDSCH/PUSCH

Possible association options btw. PDCCH and PDSCH/PUSCH

Only option 1 was agreed for Rel-10 design

Each PDSCH/PUSCH CC can be scheduled only from a single DL CC, i.e. the UE only monitors PDCCH on one DL CC for each PDSCH/PUSCH CC For any DL carrier with CIF where the UE monitors PDCCH, PDCCH on the DL carrier shall be

able to schedule PDSCH at least on the same carrier and/or PUSCH on a linked UL carrier

FFS : PDCCH monitoring CC set

The set of DL component carriers on which all PDCCHs are transmitted to an UE within a UE-specific DL active CC set

21

CC0 CC1

SS for CC0/1/2 No SS

CC2

No SS

DCI0 DCI1 DCI2

CC0 CC1

SS for CC0/1/2

CC2

DCI0 DCI1 DCI2

SS for CC0/1/2 SS for CC0/1/2

CIF

CCE index CCE index

frequency

time time

<Option 1> <Modified Option 1>

Ref : R1-102289, NTT DOCOMO


Blind Decoding and Reduction Schemes

Blind decoding for PDCCH

The transmission mode is not constrained to be the same on all CCs scheduled for a UE

Maximum number of blind decodes that must be supported by a UE even with cross-carrier scheduling:

Number of blind decodes for single carrier operation Single carrier operation without MIMO or non-contiguous resource allocation: X = 44

Non-contiguous resource allocation: X = 44

Blind decoding reduction schemes

Limited CCE aggregation levels

Reduced search space size

Size adaptation on DCI format

FFS

UL MIMO

44 x N_DLCC + Y x N_ULCC_M for UE which is configured UL MIMO

where N_ULCC_M is the number of active CCs which are configured for UL MIMO.

Y is one of 0 and 16 (FFS which one)

FFS: need for further reducing the number of blind decodes.

22


Carrier Indication Field Design

CIF mapping to CCs:

The mapping from CI values to CCs for each CC enabling CIF is UE specific

CI to CC mapping is configured by RRC At least one carrier should operate during reconfiguration of the CI-to-CC mapping

Details of CI Configuration

On the discussion between scheduling-CC specific CI or UE-specific CI

23

Scheduling CC (PDCCH monitoring CC) Scheduled CC (PDSCH/PUSCH CC)

CC #1 CC #2 CC #3 CC #4

UE-specific CCs

CIF = 0 CIF = 1 CIF = 0 CIF = 1

Scheduling CC-specific

CI configuration

<Scheduling-CC specific CI>Ref : R1-102714, LG Electronics


Carrier Indication Field Design (Cont’d)

24

UL CI-to-CC Mapping

Further discussions on the details of UL CI configuration

Three candidates can be considered as follows:

FeaturesIndependent

CI-to-CC mappingExclusive

CI-to-CC mappingLinkage-based

CI-to-CC mapping

CI ambiguity Need solutions No problem

No problem (if the bandwid

th of DL is equal to or larger

than bandwidth of linked U

L CC)

Extensibility Good

Fair (if scheduling CC-sp

ecific CC-to-CI mapping

is used)

Fair

ReconfigurationIndependent btw. DL and

UL

Independent btw. DL an

d ULSimultaneous in DL and UL

BD reduction No difference Possible to reduce BDs No difference

CI validation check Contributive Less contributive Contributive

Ref : R1-102713, LG Electronics


Search Space Design

Per-CC search space design

For a given UE, search spaces located on a PDCCH CC are individually defined per aggregation level for each PDSCH/PUSCH CC linked to the PDCCH CC

Search space sharing

A UE’s search spaces on a PDCCH CC are shared in case of same DCI size

Discuss further the details of search space design

25

Transmission mode 1

(DCI format 0/1A, 1)

Transmission mode 3

(DCI format 0/1A, 2A)

DL CC #1 DL CC #2 DL CC #3

DCI format 0/1A

DCI format 1

SS for CC pair #1 SS for CC pair #2 SS for CC pair #3

UL CC #1 UL CC #2

Linkage

Transmission mode 3

(DCI format 0/1A, 2A)

DCI format 0/1A

DCI format 2A

UL CC #3

DCI format 0/1A

DCI format 2A

Entire search space

DCI format 0/1A

DCI format 1

SS for CC pair #1 SS for CC pair #2 SS for CC pair #3

DCI format 2ARef : R1-102689, LG Electronics


PCFICH Transmission

HARQ buffer corruption problem in CA HARQ buffer corruption due to PCFICH detection errors on the component carrier

carrying PDSCH

Baseline for Rel-10 The PDSCH starting symbol position of the cross-scheduled CC is informed

to UE by RRC signaling.

No dynamic adaptation of the PDSCH starting symbol position which is applicable for HetNet scenarios

Further study for RRC signaling More than one value (for different sets of subframes) signalled by RRC is

necessary

Receive PDSCH Not receive PDSCH Receive PDSCH

PDSCH error due

to CFI error, also

leads to HARQ

buffer corruption.

PDCCH correct

CFI correct

PDCCH DTX

CFI errorPDCCH correct

CFI correct CFI errorPDCCH correct

PDCCH option 1a PDCCH option 1bRef : R1-100239, Huawei


PHICH Transmission

PHICH transmission PHICH transmission only on the DL CC

used for the relevant UL grant transmission

Re-use PHICH physical transmission aspects from Rel-8

PHICH resource mapping rules: For symmetric or DL heavy DL/UL carrier

assignment without CIF:

- Reuse of Rel-8 mapping rule

PHICH for SPS

Rel-10 PHICH for SPS is transmitted as same as Rel-8.

PHICH for non-SPS Further discussion is needed if

additional mechanism beside DM-RS CS mechanism is necessary.

If necessary, exact PHICH resource mapping rule should be further determined.

27

PDSCHPDSCHSC

H/B

CH

f

PUSCH

PUCCH

Downlink

Uplink

PUCCH

PHICH

PDCCH

PHICH

PDCCH

PUSCH

PUCCH

PUCCH

SC

H/B

CH

DL CCs for UE1

UL CC used by LTE-UE

UL CC used by LTE-A UE

CC linkage for LTE UEs(Based on LTE-SIB2)

PossibleCollision

PHICH linkage for LTE-A UE

PHICH linkage for LTE UE

UE specific CC linkage for LTE-A UE

DL CC2DL CC1

UL CC1 UL CC2

The same RB number within CC is used for LTE-A UE and LTE-UE

UL grant UL grant

Ref : R1-093468, Panasonic


PUCCH Transmission

ACK/NACK

A single UE-specific UL CC is configured semi-statically for carrying PUCCH A/N, SR, and periodic CSI from a UE.

Simultaneous A/N on PUCCH transmission from 1 UE on multiple UL CCs is not supported

Method for assigning PUCCH resource(s) for a UE on the above single UL carrier in case of carrier aggregation

It’s not supported that multiple simultaneous PUCCH transmission for A/N in multiple non-adjacent PRBs

Maximum 10 A/N bits shall be supported

Further consideration points

Exact method for A/N resource assignment and A/N resource region allocation

- PUCCH format 1b with SF reduction to 2 (it’s precluded for SF reduction to 1.)

- PUCCH format 2

- Channel selection

- A/N bundling within / across CCs

- New ACK/NACK PUCCH format design

Scheduling request

One SR PUCCH transmission semi-statically mapped onto one UE-specific UL CC

CSI (Channel Status Information)

Periodic CSI PUCCH transmission semi-statically mapped onto one UE-specific UL CC

CSI for up to 5 DL CC

Baseline: Rel8 principles for CQI/PMI/RI


Reporting overhead reduction, e.g. DL CC cycling and payload extension


Power Control for CA

Rel-10 PUCCH power control

where is the carrier-specific maximum transmit power.

Rel-10 PUSCH power control on component carrier c

If PUCCH is present on the CC

If PUCCH is not present on the CC

Path loss offset handling due to DL measurement limitation is FFS depending on RAN4 decision.

29

PUCCH CMAX 0_PUCCH F_PUCCHmin , ,c CQI HARQP i P P PL h n n F g i

CMAXcP

PUSCH CMAX PUCCH 10 PUSCH O_PUSCH TF( ) min{ ( ), 10log ( ( )) ( ) ( ) ( ) ( )}c c c c c c cP i P P i M i P j j PL i f i

PUSCH CMAX 10 PUSCH O_PUSCH TF( ) min{ , 10log ( ( )) ( ) ( ) ( ) ( )}c c c c c c cP i P M i P j j PL i f i


Power Control for CA (cont’d)

Supports of two types of PHR

Type 1: P_cmax minus PUSCH power

Type 2: P_cmax minus PUCCH power minus PUSCH power

If RAN2 decides that the Type 2 PHR can be derived for subframes where PUCCH is not actually transmitted, PUCCH Format 1A is used as the reference format.

When Type 2 PHR is derived for subframes where PUCCH is transmitted, the PUCCH format used for PHR Type 2 is the PUCCH format actually transmitted.

FFS for details waiting for RAN2 response

TPC command transmission

TPC in UL grant is applied to UL CC for which the grant applies

TPC in DL grant is applied to UL CC on which the ACK/NACK is transmitted

FFS : TPC in DCI format 3/3A

Alt 1: Semi-static configuration of multiple TPC-PUSCH-RNTI/TPC-index pairs (FFS whether multiple RNTIs are supported) to define the mapping between the TPC command and the UE/CC

- No increase in UE blind decoding attempts due to cross-carrier group power control

Alt 2: Cross-carrier group PC is not supported in Rel-10.

30


Power Control for CA (cont’d)

Per-Channel Max Power Scaling

If the total transmit power exceeds the UE max transmit power , the UE scales the transmit power of each PUSCH such that

where wc is a scaling factor for PUSCH on carrier c.

PUSCH with UCI is prioritized over PUSCH without UCI (i.e. power of PUSCH without UCI is scaled down first, maybe to zero)

i.e. Priority order is as follows:

- PUCCH > PUSCH with UCI > PUSCH without UCI

Prioritization is regardless of same or different CCs.

UCI cannot be carried on more than one PUSCH in a given subframe.

The UE shall scale the power of all PUSCHs without UCI equally.

Note that possibly setting the power of a PUSCH to zero is up to RAN4.

It is FFS in RAN1 how the UE knows which PUSCH carries the UCI in the case when the UE transmits more than one PUSCH in a given subframe.

Power control for multiple antennas

FFS

31

PUSCH CMAX PUCCH( ) ( )c c

c

w P i P P i

CMAXP


Non-Contiguous RB Allocation Baseline assumptions

Introduction of hybrid multiple access schemes based on SC-FDMA Intra-carrier frequency

- SC-FDMA keeping single-carrier property

- Clustered DFT-s-OFDMA

Inter-carrier frequency

- NxDTF-s-OFDMA

Support of non-contiguous RB allocation based on clustered DFT-s-OFDMA

Support of PUSCH-PUCCH decoupling Capability of simultaneous PUSCH and PUCCH

transmission in addition to PUSCH piggybacking

Dynamic mode adaptation btw. SC-FDMA and clustered DFT-s-OFDMA

Further consideration points RA field design for clustered DFT-s-OFDMA

Inter modulation distortion and UE power back-off issue in non-contiguous RB and PUSCH/PUCCH decoupling.

Number of clusters, size of cluster, and signaling method

Whether to support non-contiguous tx in UL MIMO

IFFT

Modulation symbol DFT DFT output

Sub-block#0

Sub-block#1

Sub-block#2

Sub-block#3

Sub-block#0

Sub-block#1

Sub-block#2

.

.

.

.

.

.

.

.

.

Sub-

block#Nsb-1

Frequency domain

mappingEx.) localized mapping

within a sub-block

For one component carrier

(eg. 20MHz BW chunk)

Clustered DFT approach

FD

T

Sub-car-rie

Map-ping

IFFT

CP

Insertion

00

0

0

00

tfe 12

FD

T

Sub-car-rie

Map-ping

IFFT

00

0

0

00

tfe 22

FD

T

Sub-car-rie

Map-ping

IFFT

00

0

0

00

tfe 32

FD

T

Sub-car-rie

Map-ping

IFFT

00

0

0

00

tfe 42

FD

T

Sub-car-rie

Map-ping

IFFT

00

0

0

ing

IFFT

00

0

0

00

tfe 32

FD

T

Sub-car-rie

Map-ping

IFFT

00

0

0

00

tfe 42

FD

T

Sub-car-rie

Map-ping

IFFT

00

0

0

00

tfe 52

Code Block

segmentation

ModulatorChannel

Coding

Chunk

Segme-

nation

ModulatorChannel

Coding

ModulatorChannel

Coding

ModulatorChannel

Coding

ModulatorChannel

Coding

NxDFT-s-OFDMA

Clustered DFT-s-OFDMA


Relay


Relay Node Types

Objectives

One of key tools in LTE-A to improve, e.g. the coverage of high data rates, group mobility, temporary network deployment, the cell-edge throughput and/or to provide coverage in new areas

Categorization

With respect to the relay node’s usage of spectrum

inband, in which case the eNB-relay link shares the same carrier frequency with relay-UE links

outband, in which case the eNB-relay link does not operate in the same carrier frequency as relay-UE links

With respect to the knowledge in the UE

transparent, in which case the UE is not aware of whether or not it communicates with the network via the relay.

non-transparent, in which case the UE is aware of whether or not it is communicating with the network via the relay.

Depending on the relaying strategy

be part of the donor cell

control cells of its own

34


Relay Types for Rel-10 WI Scope

Three types of Relay

Type-1 It control cells, each of which appears to a UE as a separate cell distinct from the donor cell

The cells shall have their own Physical Cell ID (defined in LTE Rel-8) and the relay node shall transmit its own synchronization channels, reference symbols, …

In the context of single-cell operation, the UE shall receive scheduling information and HARQ feedback directly from the relay node and send its control channels (SR/CQI/ACK) to the relay node

It shall appear as a Rel-8 eNodeB to Rel-8 UEs (i.e. be backwards compatible)

To LTE-Advanced UEs, it should be possible for a relay node to appear differently than Rel-8 eNodeB to allow for further performance enhancement.

Type-1a A “Type 1a” relay node is characterised by the same set of features as the “Type 1” relay node above, except “Type

1a” operates outband. A “Type 1a” relay node is expected to have little or no impact on RAN1 specifications.

Type-2 It does not have a separate Physical Cell ID and thus would not create any new cells.

It is transparent to Rel-8 UEs; a Rel-8 UE is not aware of the presence of a Type 2 relay node.

It can transmit PDSCH.

At least, it does not transmit CRS and PDCCH.

Scope of LTE-A

At least, type-1 and type-1a are in the scope of LTE-A.

Type-1 is in the Rel-10 WI scope.

Design for the WI should target only stationary Relay Nodes

At least two receive antennas for backhaul at RN is mandatory

35


Access/Backhaul Partitioning

TDM-based partitioning

Protection of self-interference at the RF front-end due to simultaneous Tx/Rx in the same frequency band

Further restriction point

Backward compatibility support for LTE Rel-8 UE’s measurement behavior in the access downlink for FDD mode UE expectation: legacy CRS transmission in the control channel region of every access

downlink subframe

Introduction of fake-MBSFN subframe in the access downlink

RN-specific RRC signaling for MBSFN configuration

A partial subframe OFDM symbols for backhaul downlink transmission

Blanked part of downlink subframe considering guard time for relay node Tx/Rx switching

Full subframe usage for backhaul uplink transmission36

DataCtrltransmission gap

(“MBSFN subframe”)Ctrl

One subframe

No relay-to-UE transmission

eNB-to-relay transmission


Relay Backhaul and Access Timing in DL

Three options in DL timing

Introducing a fixed timing offset (To) in addition to propagation delay (Tp) (case 1)

RN DL RX timing is aligned to RN DL TX timing (case 2)

eNB DL TX timing is aligned to RN DL TX timing (Case 3)

Supported timing options until RAN1 #61

Cases 1 and 3 are supported

The support of case 2 is still under consideration depending upon RAN4 inputs

Detailed descriptions for each option

R1-102548, “WF on DL Timing between RN and eNB”, Huawei, et al.

R-PDCCH and R-PDSCH Starting Position

R-PDCCH start symbol is fixed to symbol #3.

R-PDSCH start symbol s2 is configurable in the range m ≤ s2 ≤ 3, by high-layer signaling.

37

Fixed delay

0 13

3

012 13

eNB

Relay G1 G2

Macro subframe

Relay subframe

0 1

3

Macro

Backhaul

Backhaul

Access

Tp

Tp

13

13

To

0 13

012 13

eNB

Relay

Macro subframe

Relay subframe

0 1

Macro

Backhaul

Backhaul

Access

Tp

Tp

13

132

2

<Case 1>

<Case 2>

0 13

eNB

Relay

Macro subframe

Relay subframe

12

0 1 G1 G20 1

2

2 12

Tp

Macro

Backhaul

Backhaul

Access

“11 symbols”

<Case 3>Ref: R1-102426, LG Electronics


Relay Backhaul and Access Timing in UL

The following UL timing cases are supported without additional RAN1 specification required in Rel-10

Case 2b

UL RN Tx timing and UL RN Rx timing is staggered by a fixed gap (delayed Uu)

Modified case 2a

UL RN Tx timing and UL RN Rx timing is aligned

Modified case 4

UL eNB Rx and the UL RN Rx timing is aligned

LS to inform RAN2 and RAN4 for above agreement

Detailed descriptions of UL Timing options

R1-103399, “LS on UL timing between eNB and relay”

38

“To: Fixed delay

0 13

0 112

0

eNB

Relay G1 G2

Macro subframe

Relay subframe

Tp

Tp

13

13

Macro

Backhaul

Backhaul

Access

To

0

<Case 2b>

0 13

0 112 13

eNB

Relay

Macro subframe

Relay subframe

Tp

Tp

Macro

Backhaul

Backhaul

Access

0 13

0 13

<Modified Case 2a>

<Modified Case 4>

0 13

eNB

Relay

Macro subframe

Relay subframe

13

0 112 13 G1

1

Tp

G2

Macro

Backhaul

Backhaul

Access

13 1

RN can use SC-FDMA symbol 0 by puncturing the last SC-FDMA

symbol of the Uu link>

Ref: R1-102427, LG Electronics


Backhaul Resource Assignment

Agreement until RAN1 #61

Access link downlink subframe transmission boundary backhaul link downlink subframe reception boundary

Except for possible adjustment to allow for RN transmit/receive switching

Semi-statically explicit assignment of the set of downlink backhaul subframes

Introduction of a new physical control channel (here referred to as the “R-PDCCH”)

Dynamic or semi-persistent resource assignment for R-PDSCH or R-PUSCH

Resource assignment for R-PDCCH in the same and/or in one or more later subframes.

Within semi-statically assigned resource zone for R-PDCCH transmission,

A subset of the resource assignment used for R-PDCCH transmission

Subframe-by-subframe dynamic resource assignment for R-PDCCH transmission

Time-domain resource assignment of the full set of OFDM symbols or a constrained subset of OFDM symbols for R-PDCCH transmission

R-PDSCH or PDSCH transmission on the resources not used for R-PDCCH

Possible reuse of Rel-8 functionality for the detailed R-PDCCH transmitter processing (channel coding, interleaving, multiplexing, etc.)

Allowance of removing some unnecessary procedure or bandwidth-wasting procedure by considering the relay property

39


Backhaul Resource Assignment (cont’d)

R-PDCCH and R-PDSCH multiplexing

DL grants are always transmitted in the first slot of a subframe

- The second slot of a R-PDCCH PRB pair can be allocated to data channel for a RN receiving at least part of DL grant in the first slot of the PRB pair.

- If a DL grant is transmitted in the first PRB of a given PRB pair, then an UL grant may be transmitted in the second PRB of the PRB pair

- UL grants are only transmitted in the second slot (never in the first slot)

- No data transmission in the first slot

- FFS in case of SPS (await news from RAN2)

- Boundary between UL and DL grants is at the slot boundary.

40

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

subframe 1ms

10 ms eNB radio frame

PDSCH to macro UEs

Primary backhaul resource for RN1


Secondary backhaul resource for RN2


Secondary backhaul resource for RN3

PDSCH to macro UEs

Semi-statically assigned PRBs for R-PDCCH transmission

PD

CC

H to

mac

ro U

Es

PDSCH to macro UEs

GT GT

GT GT

GT GT

Additional R-PDSCH to RN3

(indicated by R-PDCCH to RN3 in primary backhaul

resource)

2nd slot

R-PDSCH to RN3

...

PDSCH to macro UEs

GT: Guard time for Tx/RX transition gap at RNs if necessary.

1st slot

R-PDCCH

to RN3

N PRBs

(N=1,2,…)

M PRBs

(M=1,2,…)

K symbols (K=1,2,3 or 4)



Relay: Backhaul DM-RS Design

Agreement until RAN1 #61

Starting point for RS design for each eNodeB-to-RN channel demodulation

Reuse of RS designed for eNB-to-UE transmission (i.e., Rel-8 CRS and/or Rel-10 DM-RS)

For R-PDCCH,

For a given RN, R-PDCCH demodulation RS type (CRS or DM-RS) shall not change dynamically nor depend on subframe type.

Demodulate with

- In normal subframes:

» Rel-10 DM-RS when DM-RS are configured by eNB

» Otherwise Rel-8 CRS

- In MBSFN subframes, Rel-10 DM-RS

For downlink shared data transmission on Un

Same possibilities as for R-PDCCH

Un DM-RS pattern for DL timing case 3

Alt 1: Reduced DM-RS

Alt 2: Shifted DM-RS

One alternative between Alt 1 and Alt 2 will be down-selected

- Targeting RAN1#61bis

41

Alt 1: Reduced DM-RS

Alt 2: Shifted DM-RS


Backhaul Subframe Allocation and HARQ Timing

Consideration points

Restriction on backhaul downlink subframe allocation

FDD: subframe indices of {0, 4, 5, 9}

TDD: subframe indices of {0, 1, 5, 6}

Backhaul DL/UL HARQ timing relationship

Support of LTE Rel-8 UE’s HARQ in the access link

Problematic situation for backhaul HARQ

Agreements in HARQ until RAN1 #61 For both FDD and TDD backhaul link, release 8 minimum HARQ RTT timing is the

baseline assumption for DL and UL minimum requirement from L1 processing perspective

42


DL MIMO Enhancement

Great Company Great People 44

LTE-A DL RS Configuration

DL reference signal configuration in an LTE-A cell

LTE Rel-8 cell-specific reference signal (CRS)

Demodulation for PDCCH, PCFICH, PHICH, and PDSCH(TxD)

L3 measurement (RSRP/RSRQ) measurement or [L2 measurement]

LTE-A demodulation reference signal (DM-RS)

Demodulation for PDSCH except TxD mode

LTE-A channel status information reference signal (CSI-RS)

L2 measurement

Potential reference signal configuration

LTE-A subframe (MBSFN subframe)

LTE-A optimized unicast transmission in an MBSFN subframe

By control signaling for MBSFN subframe configuration

No legacy CRS REs in the PDSCH region

Issue point

TxD transmission and its relevant RS configuration in an LTE-A subframe

1Tx CSI-RS 2Tx CSI-RS 4Tx CSI-RS 8Tx CSI-RS

1Tx CRS X ? ? O

2Tx CRS - X ? O

4Tx CRS - - X O

X: Rel-8 CRS can be used as CSI-RS for LTE-A system

O: new CSI-RS for LTE-A antenna configuration is needed

Great Company Great People45

LTE-A DL DM-RS Design

LTE-A DL DM-RS pattern in case of normal CP

For rank-1 and rank-2

12 REs, CDM, time-domain OCC of length-2

For rank-3 and rank-4

24REs, CDM+FDM, time-domain OCC of length-2

For rank-5~8

24REs, CDM+FDM, time-domain OCC of length-4

LTE-A DL DM-RS patterns in case of extended CP

Working Assumption:

In case of rank 1-2, DM-RS overhead of 16 REs per PRB pair for extended CP with normal subframe

FFS on detailed pattern

Normal subframe DwPTS with 11,12

OFDM symbols

DwPTS with 9,10

OFDM symbols Ref: R1-100800 NTT DoCoMo


DM-RS Port to Layer Mapping

Working assumptions DM-RS power offset for rank>2

Fixed 3dB power offset to corresponding layer

Definition of DM-RS port resource with two CDM groups for rank>2 1st CDM group :{port-7, port-8, port-11, port-13} 2nd CDM group :{port-9, port-10, port-12, port-14}

DM-RS port to layer mapping for rank>2 Layer n corresponds to port-(n+7), n=0,…,7 One-to-one mapping between DM-RS port and layer

For retransmission with rank = R, the same layer to DMRS port mapping rule and the same PDSCH to RE mapping rule are applied as an initial transmission with rank R

46



PRB Bundling and Details of OCC

PRB bundling

PRB bundling means that

UE may assume that precoding granularity is multiple RBs.

UE is still allowed to perform single-RB channel estimation

PRB bundling is supported when PMI/RI feedback is configured

Additional configuration of PRB bundling is FFS

The size of a PRG is only determined by the corresponding system bandwidth

FFS for details of OCC

Sequence design for OCCs and scrambling codes

47

System Bandwidth PRG size (PRB)

≤10 1

11 – 26 2

27 – 63Either 2 or 3

(decide in RAN1 #61bis)

64 – 110 2

Great Company Great People48

LTE-A DL CSI-RS Design

CSI-RS density 1RE per port per PRB for 2, 4, 8 Tx cases

Full-power utilization and CSI-RS multiplexing Negative response for 9 dB boosting per antenna

CSI RS port multiplexing is based on CDM for each pair of CSI RS port

Same data RE power between a data RE in the OFDM symbol containing CSI-RS and a data RE in the OFDM symbol without CSI-RS/Rel-8 CRS is assumed within a subframe

A nested structure among 2, 4, 8 CSI-RS ports simplifies the implementation The pattern with smaller number of CSI-RS port is a subset of the pattern with larger number of

CSI-RS port

No hopping supported A time-invariant time/frequency shift is used in a cell

Resource elements (REs) of CSIRS are configured and/or tied to system parameters for inter-cell orthogonality, i.e, no collision between CSI-RS.

Further consideration points Exact CSI-RS pattern design

Antenna port based multiplexing details

The number of OFDM symbols for CSI-RS transmission

Per antenna full-power utilization

Details on CSI-RS transmission

Period and offset considering channel measurement feedback procedures

Consideration on inter-cell CSI-RS transmission

Channel measurement for multi-cell collaborative transmission

Interference measurement


SU-/MU-MIMO

8Tx codeword-to-layer mapping

Simple extension of legacy LTE codeword-to-layer mapping

Dynamic mode adaptation btw. LTE-A DL SU-/MU-MIMO

Same DCI format design based on UE-transparency in terms of DL control signaling

MU-MIMO baselines

Dimensioning

Co-scheduling up to 4 UEs

Number of layers per UE with orthogonal RS of up to 2

Total number of layers for MU-MIMO transmission of up to 4


UE-transparency on feedback btw. LTE-A SU-MIMO and MU-MIMO

Resource allocation of orthogonal RS ports and scrambling code for MU-MIMO

Details on DCI format design

Detailed feedback procedures for SU-MIMO and MU-MIMO

49


Feedback for LTE-A

Implicit feedback (PMI/RI/CQI) is used also for Rel-10 UE spatial feedback for a subband represents a precoder (as constructed below) CQI computed based on the assumption that eNodeB uses a specific precoder (or

precoders), as given by the feedback, on each subband within the CQI reference resource Note that a subband can correspond to the whole system bandwidth

A precoder W for a subband is a function of two matrices W1 and W2, i.e. where W1 C1 and W2 C2. The codebooks C1 and C2 are codebooks one and two, respectively.

W1 targets wideband/long-term channel properties

W2 targets frequency-selective/short-term time channel properties

For PUCCH, the feedback corresponding to W1 and W2 can be sent in different or the same subframe (unless it turns out that the payload is too large to ever send W1 and W2 in the same subframe on PUCCH). Periodic and aperiodic reports are independent For PUSCH: FFS FFS whether feedback corresponding to W1 and/or W2 may be switched off

50


Feedback Signaling

Aperiodic PUSCH: Natural extension of CQI/PMI/RI modes from Rel-8/9 within R1-101683

framework

The report in aperiodic PUSCH is self-contained in the same subframe One report can contain both W1 and W2

In case one of W1/W2 is fixed, one report can contain W1 only or W2 only- Regardless of which, the precoder W is derived from W1 and W2

The same report contains RI and CQI

Periodic PUCCH Natural extension of CQI/PMI/RI modes from Rel-8/9 within R1-101683

framework

W_1/W_2 reporting procedure CSI Mode 1: W1 and W2 are signaled in separate subframes

- W2 could be wideband or subband

CSI Mode 2: W is determined by a single report confined to a single subframe, e.g.- one of W1/W2 could be fixed and hence does not need to be signaled

- W1/W2 is not fixed but still does not necessarily need to be signaled

» But the precoder W is still derived from W1 and W2

- W2 could be wideband (i.e., subband size could be the system bandwidth)

FFS: RI and CQI reporting details

51


UL MIMO Enhancement


Channel-Independent MIMO Tx.

Single antenna port mode

In this mode, the UE behavior is same as the UE behavior with single antenna from eNB’s perspective.

Exact UE implementation is left to UE vendors (e.g., PA architecture).

PUCCH, and/or PUSCH, and/or SRS transmission can be independently configured for single uplink antenna port transmission.

Detail scenarios and operation FFS.

UL Single Antenna Port Mode is the default operation mode before eNodeB is aware of the UE transmit antenna configuration.

No definition of PUSCH transmit diversity scheme

Long-term rank-1 precoding

53


Channel-Independent MIMO Tx. (cont’d)

2Tx PUCCH transmit diversity scheme

Rel-8 PUCCH format 1/1a/1b

Spatial Orthogonal-Resource Transmit Diversity (SORTD) is applied

- The same modulated symbol d(0) transmitted on different orthogonal resources for different antennas

Exact resource allocation: FFS

Candidates for PUCCH format 2/2a/2b

SORTD vs. STBC w/o band-edge hopping

New PUCCH format with payload extension

SORTD/SORSM

SCBC with multi-sequence modulation

Multi-STBC

4Tx PUCCH transmit diversity scheme

2Tx TxD is applied, and it is UE implementation issue.

54

Modulation symbol

Spreading with n_r0

Spreading with n_rM-1

n_r=(n_cs, n_oc, n_PRB) for PUCCH format 1

n_r=(n_cs, n_PRB) for PUCCH format 2Ant#0

Ant#M-1

d_0 (n)

d_0 (n)

d_0 (n)

.

.

.

-18 -16 -14 -12 -10 -8 -6 -4 -2 010

-4

10-3

10-2

10-1

SNR[dB]

Avera

ged A

CK

/NA

CK

BE

R

ETU,3km/h,|TX

|=0.0,|RX

|=0.0,PUCCH format1b,9UEs

1Tx

PVS

CDD

SC-SFBC

STBC

ORT

-18 -16 -14 -12 -10 -8 -6 -4 -2 010

-4

10-3

10-2

10-1

SNR[dB]

Avera

ged A

CK

/NA

CK

BE

R

ETU,3km/h,|TX

|=0.5,|RX

|=0.9,PUCCH format1b,9UEs

1Tx

PVS

CDD

SC-SFBC

STBC

ORT

Ref. 3GPP R1-093254 LG

Electronics


Uplink SU-MIMO

Codebook-based precoding

Independent codebook design for different ranks

Single TPMI per UL component carrier

Frequency non-selective precoding in a component carrier

TPMI size: 3bit (2Tx), 6bit (4Tx)

- Possibly can be reduced.

Transmission mode and signaling

At least two new Rel-10 UE-specific RRC-configured transmission modes for PUSCH of UE with multiple APs:

Single-antenna port mode

Multi-antenna port mode supporting up to 2 TB (the number of antenna ports depends on the UE capability).

FFS whether or not a third RRC-configured multi-antenna transmission mode is needed

For PUSCH, a dynamic switching between the configured transmission scheme and a single-port fallback scheme with the same DCI format for all RRC configured modes.

55


Uplink SU-MIMO (cont’d)


Impact on antenna gain imbalance (AGI) due to hand-gripping problem

Per-antenna power control

Antenna power amp (PA) configuration

2Tx antennas

- Case-1: 20dBm + 20dBm

- Case-2: 23dBm + 23dBm

- Case-3: 23dBm + x, where x23dBm

4Tx antennas

- Case-1: 17dBm + 17dBm + 17dBm + 17dBm

- Case-2: 23dBm + 23dBm + 23dBm + 23dBm

- Case-3: 23dBm + x + x + x, where x 23dBm

UL SU-MIMO precoding in PHICH-triggered retransmissions

Different precoding matrix selection and configuration method for retransmissions

56


UL 2Tx Codebook Design

57

1

1

2

1

Codebook

indexNumber of layers

1 2

0

1

2

3 -

4

5

1

1

2

1

10

01

2

1

j

1

2

1

j

1

2

1

0

1

2

1

1

0

2

1

Antenna turn-off vectors against AGI situation

2Tx rank-1 & 2 codebook


UL 4Tx Codebook Design – Rank 1

4Tx rank-1 codebook

Size-24: 16 constant modulus + 8 antenna-pair turn-off vectors

QPSK alphabet for rank-1 precoding proposals other than the rank-1 precoding specified in LTE Rel-8

58

Index 0

to 7

Index 8

to 15

Index 16

to 23

1

1

1

1

2

1

j

j

1

1

2

1

1

1

1

1

2

1

j

j

1

1

2

1

j

j

1

1

2

1

1

1

2

1

j

j

j

j

1

1

2

1

1

1

2

1

j

j

1

1

1

1

2

1

j

j

1

1

2

1

1

1

1

1

2

1

j

j

1

1

2

1

j

j

1

1

2

1

1

1

2

1

j

j

j

j

1

1

2

1

1

1

2

1

j

j

0

1

0

1

2

1

0

1

0

1

2

1

0

0

1

2

1

j

0

0

1

2

1

j

1

0

1

0

2

1

j

0

1

0

2

1

j

0

1

0

2

1

1

0

1

0

2

1

Antenna turn-off vectors against AGI situation


UL 4Tx Codebook Design – Rank 2

4Tx rank-2 codebook

Size-16: CM-preserving matrices

QPSK alphabet

59

Index 0

to 7

Index 8

to 15

j

1

0

0

0

0

1

1

2

1

j

1

0

0

0

0

1

1

2

1

1

1

0

0

0

0

1

2

1 j

1

1

0

0

0

0

1

2

1 j

j

1

0

0

0

0

1

1

2

1

j

1

0

0

0

0

1

1

2

1

1

1

0

0

0

0

1

2

1 j

1

1

0

0

0

0

1

2

1 j

1

0

1

0

0

1

0

1

2

1

1

0

1

0

0

1

0

1

2

1

1

0

1

0

0

1

0

1

2

1

1

0

1

0

0

1

0

1

2

1

0

1

1

0

1

0

0

1

2

1

0

1

1

0

1

0

0

1

2

1

0

1

1

0

1

0

0

1

2

1

0

1

1

0

1

0

0

1

2

1


UL 4Tx Codebook Design – Rank 3 & 4

4Tx rank 3 codebook

Size-12 : CM-preserving matrices

BPSK for simplicity

4Tx rank-4 codebook

Single identity matrix

60

Index 0

to 3

Index 4

to 7

Index 8

to 11

100

010

001

001

2

1

100

010

001

001

2

1

100

001

010

001

2

1

100

001

010

001

2

1

001

100

010

001

2

1

001

100

010

001

2

1

100

001

001

010

2

1

100

001

001

010

2

1

001

100

001

010

2

1

001

100

001

010

2

1

001

001

100

010

2

1

001

001

100

010

2

1


DM-RS and Orthogonal Cover Code (OCC)

Precoded UL DM-RS

2Tx antennas

Precoded DM-RS both for rank-1 and rank-2 (using identity matrix)

4Tx antennas

Precoded DM-RS for all rank cases

- DM-RS precoding for rank-4 (using identity matrix)

- Potential agreement of precoded DM-RS in case of rank-3

UL DM-RS multiplexing

Baseline: cyclic shift (CS) separation for DM-RS multiplexing

Segmentation based DM-RS sequence mapping for non-contiguous RB allocation for MU-MIMO

Introduce the OCC in Rel-10 without increasing UL grant signaling overhead

OCC can be used for both SU and MU-MIMO

FFS

- Cyclic shift configuration for multiple layers

- Configuration between OCC and CS index

Sequence hopping/sequence group hopping

Rel-8/9 cell-specific enabling or disabling of sequence group hopping is available in Rel-10

FFS for introducing new hopping mechanism

61


Enhanced SRS

Baseline assumptions for enhanced SRS

Periodic SRS: Re-use of Rel-8 principles (CS separation, IFDM separation)

Non-precoded (antenna specific) SRS for LTE-A UE

Independent SRS configuration per CC in case of carrier aggregation

Aperiodic SRS

Triggering method

At least supported by PDCCH UL grants

- In case of DCI format 0 is used for SRS triggering, size of DCI format 0 remains the same as defined in Rel8 at least in common search space

FFS for allowing triggering without PUSCH grant

FFS for triggering by DL grant and by DCI format 3/3A

SRS duration

One-shot SRS transmission is supported.

FFS for timer-based aperiodic SRS

FFS for resources used for aperiodic SRS

Reuse of Rel-8 periodic SRS resources

Introduction of new SRS resources, e.g., sounding via DM-RS

FFS for SRS configuration for multi-antenna support

Simultaneous SRS transmission from all transmit antennas

SRS transmission from partial transmit antennas

62


Layer Shifting/HARQ Bundling for UL SU-MIMO

No Layer shifting

Changes in layer-to-port mapping every SC-FDMA symbol

No support for layer shifting in Rel-10

No HARQ bundling for UL SU-MIMO

2 NDIs (one NDI per CW) in the DCI format associated with UL SU-MIMO.

2 HARQ A/N Limit PHICH design to one to one mapping between an A/N and an existing

PHICH resource

For a single CC UL MIMO transmission, the PHICH resources for CW1 and CW2 are identified by

- The CSI value associated with the PUSCH transmission

- Different PRB indices for the PUSCH, assuming more than one PRBs for the transmission

- (I,Q) branches of a QPSK symbol within one PHICH group

63


UCI Piggybacking

UCI Piggybacking for SU-MIMO

HARQ-ACK and RI:

Replicated across all layers of both CWs

TDM multiplexed with data such that UCI symbols are time-aligned across all layers FFS: How to determine the number of UCI symbols on each CW and each layer

CQI/PMI: transmitted only on 1 codeword

Reuse Rel-8 multiplexing and channel interleaving mechanisms Extension: The input to data-control multiplexing { , } is grouped into

column vectors of length Q_m*L

- L (1 or 2) is the number of layers the CW is mapped onto

- Enable time (RE) alignment across 2 layers for L=2

UCI symbol-level layer mapping: same as (treated as a part of) data

FFS: Mechanism for CW selection

64

0 1 2 3 1, , , ,...,CQIQq q q q q 0 1 2 3 1, , , ,..., Gf f f f f

0 1 2 3 1, , , ,...,

Hg g g g g

CQI

RI

ACK

RS RS

DATA

SC-FDM symbols

time

do

ma

in m

od

ula

ted

sym

bo

ls

for e

ach

SC

-FD

M s

ym

bo

l

Rel-8 UCI Piggybacking in PUSCH UCI Piggybacking for multiple layers

Ref: R1-102762, Qualcomm


References

Chairman’s notes RAN1 #59bis, #60, #60bis, and #61

3GPP TS 36.211: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical channels and modulation".

3GPP TS 36.212: “Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding".

3GPP TS 36.213: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures".

3GPP TR 36.814: “Further Advancements for E-UTRA Physical Layer Aspects”

Stephen Hayes , “3GPP Technology Standards Roadmap Mobile Broadband Outlook for the Americas”, Mobile Broadband Outlook for the America, Apr. 2010.

Takehiro Nakamura, “Proposal for Candidate Radio Interface Technologies for IMT-Advanced Based on LTE Release 10 and Beyond (LTE-Advanced)” ITU-R WP 5D 3rd Workshop on IMT-Advanced, Oct. 2009.

Jaehoon Chung, “3GPP LTE-Advanced: Physical Layer Technologies”, 16th Wireless Communications Workshop .

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Key Issues of 3GPP LTE-Advanced - krnet.or.krB9... · Key Issues of 3GPP LTE-Advanced June 21th, 2010 ... It includes work on both 2nd and 4th generation technologies. ... (MIMO,