出國報告（出國類別：其他）

3GPP RAN1 #72bis Meeting

會議報告

出國人員：郭秉衡、邱頌恩、謝佳妏、鄭延修、邱哲盛

派赴國家：美國/芝加哥

出國期間：102年 4月 13日至 102年 4月 22日

報告日期：102年 5月 17日

2

摘 要

此次 RAN1#72Bis的議程包括 New Carrier Type、eIMTA、Downlink MIMO

Enhancements、3D-MIMO、Network-Assisted Interference Cancellation (NAIC)、

Low-cost MTC、D2D和 Small Cell Enhancements，參加這次會議的目的在於持

續關注 LTE-A Rel-12標準制定的動向及各家公司提案方向，以利於及早布局我

方往後在標準制定工作上的策略方針。另一個主要目的在於更加深入了解針對

一些新技術的模擬環境假設，以便於我們未來模擬平台的建構與發展。

會議解說：

3GPP RAN1 Meeting #72bis會期於 2013年 4月 15日至 2013年 4月 19日

在美國芝加哥舉行。本團隊在本次會議著重於 Device to Device (D2D)

Communications 並關注新的工作項目如 Network Assisted Interference

Cancellation、Low-cost MTC、Small Cell Discovery、NCT。

3

目 錄

摘 要 .......................................................................................................... 2

一、會議名稱 ............................................................................................ 4

二、參加會議目的及效益 ........................................................................ 4

三、會議時間 ............................................................................................ 5

四、會議地點 ............................................................................................ 5

五、會議議程 ............................................................................................ 5

六、會議紀要 ............................................................................................ 7

七、心得與建議 ...................................................................................... 36

4

一、會議名稱

3GPP TSG RAN1 #72Bis Meeting

二、參加會議目的及效益

參與 3GPP RAN1並關注 Rel-12的議題包括 UMTS HetNet、New Carrier

Type、eIMTA、DL MIMO enhancements、3D-MIMO、Low-Cost MTC、

D2D、Network-Assisted Interference Cancellation and Suppression 和 Small

cell Enhancements等，並參與討論以追蹤各項技術項目之進展。

RAN 1目前所討論的議題如下：

New Carrier Type for LTE：

- Study of new DL DMRS patterns

- Standalone NCT: Evaluation of benefits and identification of scenarios

Further Downlink MIMO Enhancements for LTE-A ：

- 4-tx codebook

- Other details of new aperiodic PUSCH feedback modeRemaining details of DCI

formats

Further Enhancements to LTE TDD for DL-UL Interference Management and Traffic

Adaptation：

- Interference Mitigation Schemes

- Signalling mechanisms for TDD UL-DL reconfiguration

Study on Provision of Low-cost MTC UEs based on LTE：

- PSS/SSS

- PBCH

- PRACH

- PDSCH/PUSCH

- (E)PDCCH

- PUCCH

5

Study on Small Cell Enhancements : Physical-Layer Aspects

- Remaining aspects of evaluation assumptions

- Enhancements for improved spectral efficiency

- Control Signaling

- Higher-order Modulation

Mechanism for Efficient Small Cells Operation

- Interference avoidance and coordination

- Small cell discovery

Study on 3D-channel model for elevation beamforming and FD-MIMO

- Remaining details of scenarios

- Modifications to the 3GPP evaluation methodology

Study on LTE Device to Device Proximity Services

Study on Network-assisted Interference Cancellation and Suppression for LTE

報告本團隊所發表的文章

發表系統實作所發現的相關議題，增進實作技術和系統概念的交流

與其他大廠接觸以討論合作項目

三、會議時間

15 Apr.- 19 Apr. 2013

四、會議地點

Palmer House Hilton Hotel (Chicago, IL, USA)

五、會議議程

RAN1 的會議議程如下:

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7

六、會議紀要

會議資訊摘要：

本次會議由 North American Friends of 3GPP 主辦，共約有 324人參加。除

了 RAN1 #72bis會議之外，RAN2 #81bis、RAN3 #79bis及 RAN4 #66bis等

工作組(Working Group，WG)亦同時召開。

台灣派員參與此次會議之公司/機構有 ACER、ASUS、CHTTL、HTC、III、

ITRI及 MediaTek等 7家。

本次會議 UTRA Rel-12 WCDMA/HSPA+相關技術議題共有 5個議程，包括

1個工作項目(Work Item，WI)及 4個研究項目(Study Item，SI))，分別為：

1. Agenda Item 6.2: (WI) HSPA Signalling Enhancements for More Efficient

Resource Usage for LCR TDD

2. Agenda Item 6.3: (SI) Study on UMTS Heterogeneous Networks

3. Agenda Item 6.4: (SI) Study on DCH Enhancements for UMTS

4. Agenda Item 6.5: (SI) Study on Scalable UMTS

5. Agenda Item 6.6: (SI) Study on Further EUL Enhancements

本次會議 E-UTRA Rel-12 LTE/LTE-A 相關技術議題共有 8個議程，包括 3

個 WI及 5個 SI，分別為：

1. Agenda Item 7.2.1: (WI) New Carrier Type for LTE

2. Agenda Item 7.2.2: (WI) Further Downlink MIMO Enhancement for

LTE-AdvancedFurther Enhanced Non-CA-Based ICIC for LTE

3. Agenda Item 7.2.3: (WI) Further Enhancements to LTE TDD for DL-UL

Interference Management and Traffic Adaptation Network-Based

Positioning Support for LTE

4. Agenda Item 7.2.4: (SI) Study on Provision of Low-cost MTC UEs based

on LTE

5. Agenda Item 7.2.5: (SI) Study on Small Cell Enhancements –

Physical-layer Aspects

6. Agenda Item 7.2.6: (SI) Study on 3D-channel model for Elevation

8

Beamforming and FD-MIMO

7. Agenda Item 7.2.7: (SI) Study on LTE Device to Device Proximity Services

8. Agenda Item 7.2.8: (SI) Study on Network-Assisted Interference

Cancellation and Suppression for LTE

本次會期 Rel-12 LTE/LTE-A共有 8個WIs/SIs進行討論，技術議題數目與

前次 RAN1#72 會議相較增加「Study on Network-Assisted Interference

Cancellation and Suppression for LTE (NAICS)」一項 SI。此 SI由MediaTek

領銜於今年 2月底 RAN Plenary #59 Meeting 提出並獲通過，共有超過 30

家公司支持，其中支持的 Operator 有 Orange、Telefonica、CHTTL、US

Cellular、Verizon Wireless、China Telecom、China Mobile、T-Mobile USA、

Deutsche Telekom、Telecom Italia、Sprint、China Unicom、Lightsquared、

Softbank Mobile等 14家。由電信營運商關注程度看來，此 NAICS SI勢將

成為 Rel-12 LTE/LTE-A重要研究發展議題之一。

這次大會中，本團隊主要負責專注 DL MIMO Enhancemen、Elevation

Beamforming and FD-MIMO、D2D、Small Cell Enhacement、UMTS HetNet、

Network-assisted Interference Cancellation (NAIC)等議題的發展概況。本章節將

簡述這幾項議題的最新進度。

1. 『UMTS Heterogeneous Networks』研究項目發展摘要：

具同頻(co-channel)干擾時之評估結果

Huawei於「R1-131482 Summary of email discussions on the alignment of

simulation results」文件，彙整各家公司在 UMTS HetNet同頻佈建且基

於 full buffer假設時之 downlink模擬結果(如表一所示)。

由評估結果可發現，與 macro-only同質網路相較，UMTS HetNet 的確

具有顯著增益，且各家公司結果趨於收斂，因此會議通過將 full buffer

評估結果納入 TR25.800 文件，不過呈現方式尚須討論。Huawei 彙整

UMTS HetNet模擬結果(R1-131482) 如下表所示：

9

Downlink Throughput

Offload

[%]

LPN is

empty

[%]

LPN

serves

one UE

[%]

RX

Type

Mean

[kbps] Gain

Median

[kbps] Gain

5%

[kbps] Gain

Alcatel-Luc

ent

Baseline 261 263 140 Type3

HetNet 1083 316% 368 40% 199 42% 34% 21% 38%

CHTTL

Baseline 391 308 102 Type3i

HetNet 1580 304% 666 116% 135 32% 35% 25% 28%

Ericsson

Baseline 406 354 76 Type3

HetNet 1493 267% 743 110% 145 92% 34% 35% 36%

Huawei

Baseline 612 604 251 Type3i

HetNet 2130 248% 1092 81% 337 34% 31% 26% 35%

NSN

Baseline 365 293 105 Type3i

HetNet 1414 287% 556 90% 147 40% 27% 30% 41%

Qualcomm

Baseline 518 486 220 Type3i

HetNet 1707 230% 827 70% 318 45% 29% 28% 40%

Renesas

Baseline 374 329 120 Type3i

HetNet 1534 310% 646 96% 173 43% 29% 28% 37%

ZTE

Baseline 477 312 81 Type3

HetNet 1237 160% 545 75% 124 53% 28% 27% 26%

此次會議本團隊亦提出模擬結果及看法(R1-131214)，我們的見解如下：

在同頻佈建時，HetNet不論在 full buffer 或 bursty情況皆於平均、

50%-tile、以及 5% -tile (i.e., cell edge)用戶流通量(user throughput)

呈現顯著增益。(此看法與大部分公司相同)

增加 LPN (low power node)發射功率與 CIO (cell individual offset)可

改進整體用戶流通量效能。(如下圖所示)

10

結合 CIO及 Multiflow SF-DC (single frequency dual cell)技術可進一

步提升細胞邊緣用戶體驗，同時系統容量亦能維持。(如下圖所示)

2. Further Downlink MIMO Enhancement for LTE-Advanced

關於 DL MIMO Enhancement 的 Working Item在上次會議已經正式開始討

論，主要方向可分為 4-TX 系統下的預編碼碼書(codebook)加強、以及新的

PUSCH反饋模式(feedback mode)以更進一步改善SU-MIMO和MU-MIMO下行

鏈路的傳輸效能。上次會議所達成的Working Assumption為：

Working Assumptions:

• A new aperiodic PUSCH feedback mode is supported in Rel.12 with following feedback

– CQI and rank feedback bit size as in PUSCH Mode 3-1 in Rel 10

– A wideband PMI

• 2 Tx: 0 bit

11

• 4 Tx: FFS with the consideration of codebook enhancement in Rel. 12 not

excluding 0 bit wideband PMI

• 8 Tx: 4/4/2/2/2/2/2/0 bits for rank 1-8 respectively

– Per subband PMI(s)

• 2Tx: 2/1 bits for rank 1 – 2

• 4Tx: FFS with the consideration of codebook enhancement in Rel.12

• 8Tx: 4/4/4/3/0/0/0/0 bits for rank 1 – 8 respectively

• Use Rel 10 W=W1W2 codebook structure for 4 antenna feedback for DMRS based TMs

• The following are for further study and evaluation:

– Subband size

– Detailed W1 and W2 structures, e.g. W1 corresponds to a long term and/or

wideband channel properties and W2 corresponds to a short-term and

narrowband channel

– Additional information in the CSI reports for this new feedback mode

For example CSI feedback enhancements targeted at improving MU

performance

(Note that the current Rel-10 4tx codebook has W=W1W2 structure).

在此 Working Item 之下，細分兩個 agenda items：

4-TX codebook

Other details of new aperiodic PUSCH feedback mode

在 codebook 的部分，此次會議前多家公司已透過 email discussion 分享各

自的 codebook提案，以方便各方模擬並比較其效能。因此，這次會議中大多數

的 contributions都是以呈現模擬結果為主。討論中較有爭議的問題在於：

1. Rel-8 codebook should be included in the new codebook for rank 1-2:

Yes: TI, Intel, ZTE,

No: Broadcom, AT&T, Samsung, Ericsson, ST-Ericsson, Alcatel-Lucent, Alcatel-Lucent

Shanghai Bell, Qualcomm, CATT, Nokia, NSN, LGE,

2. The new codebook should use constant modulus or Non-constant modulus:

Constant modulus: Samsung, Alcatel-Lucent, Alcatel-Lucent Shanghai Bell, AT&T,

Broadcom, NSN, Nokia, Renesas, Ericsson, ST-Ericsson, Fujitsu, CATT

Non-constant modulus: Docomo, Motorola, Huawei, HiSilicon, Intel, NEC

12

最後討論基於由 Alcatel-Lucent 主導的 Way Forward (R1-131719)，對於

codebook的設計結構大會達到了以下的 agreement:

Agreement:

• Adopt a new 4 tx codebook at least for rank 1-2

Working assumption for rank 1-4:

• New 4 tx codebook is constant modulus

– Companies can provide further evaluations for Scenario C1 until RAN1#73 if

desired

Working assumption:

• At least for rank 1-2:

– 4Tx codebook enhancement is based on a grid of beams design similar to the Rel

10 8Tx codebook

• (this does not preclude that some of the Rel-8 codewords might be

included in the new codebook)

– a same W1 codebook is assumed for rank 1 and rank 2 feedback

• FFS until RAN1#73 whether rank 3-4 is:

– same as Rel-8 or

– enhanced or

– not supported in the new codebook

• If rank 3-4 is supported in the new codebook, a same W1 codebook is assumed for rank 3

and rank 4 feedback

Working assumption for structure of W1:

• For each rank R =1,2 (and 3 and 4, if 4Tx codebook enhancement of rank 3 and 4 is

supported in Rel 12), W1 is defined as below

1,..,1,0,0

011

Nn

n

n

X

XW

nRC,n,n aaanqqq ,21

111

111

X

Where Xn is a 2xCR matrix with DFT columns and 12

1

πj/Qeq

• To be determined:

– N1: total number entries of W1 per rank

– Q1: granularity of beam of W1

– For each block matrix Xn

• CR: total number of beams

• a1,n, …, aCR,n : beam coefficients determining specific directions within

13

the block

Working assumption for structure of W2:

• For each rank R =1,2 (and 3 and 4, if 4Tx codebook enhancement of rank 3 and 4 is

supported in Rel 12), W2 is a 2CR x R matrix defined as below

RaaW 12

2

2

1

/2

2121

22

12 and ,...,, where Qj

crr

r

m

r

m

r eqq

qr

r

eeyy

y

ya

where ei is a selection vector of zeros and a “1” in the ith row

• To be determined:

– N2: total number entries of W2 per rank

– Q2: co-phasing granularity between two polarizations

– For each ar

• yr1: column selection for the first polarization

• yr2 : column selection for the another polarization

• mr1: phase shift for the first polarization

• mr2: phase shift for the second polarization

Working Assumption of Codebook Parameters of Rank 1 and Rank 2

• W1 (4 bits)

– N1 16

– Q1, q1: FFS

– For each block matrix Xn

• CR: FFS between 2 and 4 (4 is the default)

• a1,n, …, aCR,n : FFS

• W2 (3 or 4 bits) and three alternatives for column selection (assuming CR=4):

– Alt.1 (4 bits) same as 8Tx W2

– Alt.2 (3 bits) subset of 8Tx W2

– Alt.3 (4 bits) as 8Tx W2 modified to

• For rank 1

2

1 ,

2

1 ,

2

1 ,

2

1

2

1

2

1

2

1

2

1

22Y

Y

Y

Y

Y

Y

Y

YW

jjC 432121

~,~,~,~ , eeeeYY

• For rank 2

2

1,

2

1

22

11

22

11

22YY

YY

YY

YYW

jjC

– Alt.4 (4 bits) as Alt 3 with independent Y1, Y2, Y3, Y4 (Mihai to provide more

detailed description by Friday)

14

Working assumption for rank 3,4 (if new codebook is agreed for rank 3-4):

- W1: 2 bits

- W2: 4 or 3 (FFS) bits for rank 3, 3 bits for rank 4

在 PUSCH feedback mode 方面，主要討論該模式下應反饋的基本內容，包

括 wideband CQI、subband CQI、wideband PMI和 subband PMI等等。其中，各

家公司代表對於 feedback mode 3-2 中 PMI 回報的 subband size 定義有不同看

法。一般來說，較小的 subband size表示較高的 frequency granularity，理論上

能比較有效地讓傳送端評估頻域上的通道變化而提供較好的效能，但也同時意

味著較大的反饋量。部分公司認為該 subband size應與 mode 3-1的 CQI回報相

同，也有公司認為 subband size 可用 RRC訊號來動態調整。最後的共識如下：

Agreements:

• A new aperiodic PUSCH feedback mode is supported in Rel.12 with following feedback:

– A wideband CQI: 4 bits

– Per subband differential CQI with respect to wideband CQI as PUSCH 3-1 : 2 bits

– A wideband PMI based on W1 codebook

• 2 Tx: 0 bit

• 4 Tx:

– 0/0 bits for rank 1-2 respectively if Rel 8 codebook is configured

to the UE

– FFS for rank 3-4

– FFS if Rel 12 dual codebook is configured to the UE

• 8 Tx: 4/4/2/2/2/2/2/0 bits for rank 1-8 respectively

– Per subband PMI(s) based on W2 codebook

• 2Tx: 2/1 bits for rank 1 – 2 based on Rel 8 2Tx codebook

• 4Tx:

– 4/4 bits for rank 1-2 respectively if Rel 8 codebook is configured

to the UE

– FFS for rank 3-4

– FFS for rank 1-4 if Rel 12 dual codebook is configured to the UE

• 8Tx: 0/0/0/0 bits for rank 5 – 8 respectively

– FFS until RAN1#73 for rank 1-4 with codebook sub-sampling

– Subband Size

15

– Working assumption that the CQI and PMI subband sizes are the same

– Revisit if a problem emerges when finalising the feedback report

sizes

– Study further until RAN1#73 whether there is a benefit from

allowing different CQI and PMI subband sizes

– Working assumption that the existing CQI and PMI subband sizes are used

– Study further until RAN1#73 whether there is a benefit from

RRC-configurable subband sizes

– Additional information in the CSI reports is FFS

– For example CSI feedback enhancements targeted at improving MU

performance

• Confirm working assumption of using Rel 10 W=W1W2 codebook structure for 4

antenna feedback for DMRS based TMs

• The new aperiodic PUSCH feedback mode 3-2 can be only configured for DMRS-based

transmission mode 8,9, and 10 when PMI/RI reporting is configured;

• Working assumption that the aperiodic PUSCH feedback mode 3-2 can be configured for

TM4,6 when the Rel-8 codebook is used

• Revisit at RAN1#73 if a problem is found with TM4,6, or if no gain is found.

• A new Rel-12 codebook is not applicable to TM4,6

• Assuming a new 4Tx codebook is introduced, it should be supported for all aperiodic

reporting modes that are valid for TMs 8,9,10 when PMI/RI reporting is configured and

periodic feedback modes 2-1 and 1-1

• Assuming a new 4Tx codebook is introduced, RRC configuration per CSI process

determines whether the UE uses the Rel-8 4Tx codebook or the Rel-12 dual

codebook.

會議中也能針對 MU-MIMO的 Feedback Enhancements 做了部分討論，但

由於時間的關係，並沒有特別明確的決議。

3. Study on 3D-channel model for Elevation Beamforming and FD-MIMO

關於 3D-MIMO 的 study item 同樣也是上次會期正式開始探討的新議題。

與傳統MIMO技術相比，3D-MIMO多了 elevation的自由度，因此，該技術重

點為透過主動式天線系統(active antenna systems 或 AAS)及二維的天線配置將

信號能量更精準地聚焦於目標方向，以提升信號品質，並降低對其他用戶所造

成的干擾。

16

此次會議的重點在於模擬平台的環境假設及參數設定，包括 UE 在服務範

圍內的分布，接收端高度的設定，基站天線的高度以及天線的假定模型等等。

大會達成了以下決議：

Agree on the proposals in the two tables plus the following

• Working assumption on number of floors (for UE height):

– Uniformly distributed with an average and variation range

– Average number of floor: 6 for both UMa and UMi

– Variation range: [-2 to 2]

– Additional values or adjustments can be FFS as needed

• For a given UE, the UE height calculation has a two-step process:

– Follow the above-mentioned distribute to find the number of floors x,

– The actual floor the UE is on follows the uniform distribution of [1,x],

• Heterogeneous Networks

– Channel models developed for Urban Micro cell with high UE density and Urban Macro cell

with high UE density scenarios shall support heterogeneous deployment scenarios.

– It is assumed that for heterogeneous deployment scenarios the macro BS

height is at 25m and the lower-power node is at 10m height.

- Assumptions in Table 2 are for calibration purposes only in this SI

- Assumptions in Table 2 to be revisited for evaluating relative performance of proposed

solutions in future Sis

- *Alternative value = 200m (FFS)

Table 1:

Urban Micro cell

with high UE

density

Urban Macro cell

with high UE

density

Layout Hexagonal grid, 19 micro

sites,3 sectors per site

Hexagonal grid, 19 macro

sites,3 sectors per site

UE mobility

(movement 3kmph 3kmph

17

In horizontal plane)

BS antenna height 10m 25m

Total BS Tx Power 41/44 dBm for 10/20MHz 46/49 dBm for 10/20MHz

Carrier frequency 2 GHz 2 GHz

Min. UE-eNB 2D distance 10m [other values FFS] 35m

UE height model

general equation hUE=3(nfl – 1) + 1.5m hUE=3(nfl – 1) + 1.5m

nfl for outdoor UEs 1 1

nfl for indoor UEs Replaced by WA Replaced by WA

Indoor UE fraction 80% 80%

Pathloss

Indoor UE 2D distance from

external building wall din for

pathloss determination

uniform(0,25m) uniform(0,25m)

Table 2:

Urban Micro cell

with high UE

density

Urban Macro cell

with high UE

density

UE distribution (in x-y

plane) Outdoor UEs uniform in cell uniform in cell

Indoor UEs uniform in cell uniform in cell

Building model Dimensions (in x-y plane) not needed not needed

Number of buildings per

macro cell NA NA

Distribution of buildings in a

macro cell NA NA

ISD 200m 500m*

關於更多模擬方法的細節將持續在此次會議後的 email discussion中進行討

論。

4. Network-Assisted Interference Cancellation (NAIC)

LTE Rel-12 NAIC 技術本次會議為第一次討論。RAN 才剛剛通過這個 SI

並準備在今年剩下的幾次會議內完成這項研究議程。在考慮情境的部分，這次

會議主要是討論 NAIC 最需要被評估的場景，以作為給 RAN4的參考，使他們

能夠建立 link level simulation的假設，並去評估出各種不同的Advanced Receiver

18

的表現與複雜度。本項目相關議題如下：

Agree on the deployment scenarios, including any prioritization

Agree on inter-cell interference conditions resulted from considered inter-cell

coordination including the case of no coordination

Agree on any additional intra-cell interference resulted from MU-MIMO operation

Agree on the targeted victim data/control channel(s) of interest and associated

transmission mode, corresponding interference data/control channel(s) and associated

transmission mode, and any additional interference reference signals

Agree on evaluation assumptions

Note: Aim for agreement on as much details as possible, especially if MU

and/or CoMP schemes are considered since both affect inter- and/or intra-cell

interference observed at UEs. Sufficient level of detail, especially the assumed

behavior of UE feedback and scheduler, should be agreed to kick off interference

modeling discussion for link-level evaluation in RAN4.

由於是第一次討論，各家公司對於需要考慮的情境都各持意見，並且對於

技術報告的文字都頗斤斤計較。除了模擬情境外，對於所以考量的互相干擾的

通道，也有許多公司提出了意見。如 Ericsson 所提出的這篇 contribution

(R1-131333) 把所有的可能皆考慮進來：

Nine different channel interference conditions (CHICOs)

due to three different physical channel types.

Interfering Channel

PDSCH ePDCCH PDCCH

Vic

tim

Chan

nel

c

PDSCH CHICO1 CHICO2 CHICO3

ePDCCH CHICO4 CHICO5 CHICO6

PDCCH CHICO7 CHICO8 CHICO9

Proposal 1: Techniques for mitigating interference on PDSCH, ePDCCH and PDCCH

shall be studied assuming interference can come from PDSCH, ePDCCH, PDCCH, or a

mixture thereof.

19

但大部分公司比較支持優先考量 PDSCH 會遭受到的干擾 (CRS 或其他

PDSCH)。最後大家把主要焦點專注於一篇由 Orange, Telecom Italia, Deutsche

Telekom, T-Mobile USA, China Unicom, KDDI, Docomo, Vodafone 等電信業者

所共同提出的 Way Forward (R1-131687)。

對於此篇 WF其他公司也提出了以下幾點評論修正:

- Consider including CoMP/eICIC schemes as baseline

- Channels of interest: Consider taking PDSCH as first priority

- Consider replacing last bullet with prioritisation of CRS-based TMs over DMRS based

TMs

- Consider intra-cell MU-MIMO separatelyConsider larger / smaller ISDs .

經過許多討論，最後對於考慮情境的決議如下：

Agreements:

- NAICS Scenario 1:

o Homogeneous network, macro only, ISD = 500m

o ITU UMa channel model

o Non-ideal backhaul between sites (same assumptions as for SCE SI)

o Coordination assumptions:

Intra-site information exchange is possible

Inter-site information exchange is subject to the backhaul latency

FFS whether complexity of information exchange is also taken into

account

o NB: This scenario is similar to CoMP scenario 1 in TR36.819

Proposal 2: Partially overlapping physical channels is a typical interference condition in

the investigations

aggressor PDCCH

aggressor PDSCH

victim PDCCH

victim PDSCH

20

eNB

Coordination area

- NAICS Scenario 2a:

o SCE Scenario 1, with the modification that the small cell deployment is sparse not

clustered (FFS: 4 or 10 per macro)

o Backhaul assumptions:

Between macro-cell and small cells within its coverage, and small nodes

under the coverage of one macro: Non-ideal

Between macros of different sites: Non-ideal

o Coordination assumptions:

Intra-site information exchange is possible

Inter-site information exchange is subject to the backhaul latency

FFS whether complexity of information exchange is also taken into

account

- NAICS Scenario 2b:

o Same as NAICS Scenario 2a, with the following exceptions:

21

o Backhaul assumptions between macro and small nodes within its coverage, and

between small nodes under the coverage of one macro: “fibre access 4” as per

TR36.932

o Coordination assumptions:

According to the backhaul assumptions, information exchange is possible

in the following cases:

Intra-site

Between a macro and a small node within its coverage

Among small nodes within the coverage of the same macro

According to the backhaul assumptions, the information exchange is

subject to the backhaul latency (+ FFS complexity) in the following cases:

Inter-site between macros

Between a macro and a small node outside its coverage

Among small nodes within the coverage of different macros

- Synchronization error

o To be defined by RAN4

- Exact latency value corresponding to non-ideal backhaul is FFS from the values

considered in the SCE SI

- General for all scenarios:

o Baseline is Rel-11

o Baseline for comparison should be the appropriate Rel-11 technique(s) for each

scenario – to be agreed for each scenario

o CRS interference modelling is included

FFS number of antenna ports and number of MBSFN subframes

CRS interference cancellation at the UE is assumed for all subframes for

up to 2 interfering cells

o Traffic model: FTP model 1

5. Further Enhancements to LTE TDD for DL-UL Interference Management

22

and Traffic Adaptation

在 3GPP RAN#58 會議中，分時多工系統增強干擾消除和流量調整議題

(TDD eIMTA)已同意被 3GPP Rel-12採納，其應用為未來非常重要的研究與發

展標的。此次會議的討論著重於兩大方向：

干擾消除的方法

分時多工系統重新組態(reconfiguration)訊號通知的機制

在干擾消除方法的部分，此次會議做出了以下決議：

7.2.3.1 Interference mitigation schemes

(Focus on understanding the benefits and standard impacts of the proposed IM schemes.)

Working assumption:

• At least for UL, the following scheme is supported for dynamic TDD UL-DL

reconfigurations:

– Depending on the type of a subframe and/or type of interference seen by a

subframe, the power control parameters and/or mechansim could be different

between a flexible subframe and a fixed subframe

• Details of subframe-type dependent power control is FFS

• Companies are encouraged to bring detailed proposals and performance evaluations in

the next meeting.

Agreement:

• Backhaul signaling capturing eNB-to-eNB interference can be beneficial for TDD

eIMTA

• Working assumption that New backhaul signaling capturing eNB-to-eNB interference is

to be introduced

– To be confirmed if gains are shown by evaluations in following meeting(s)

– FFS on the detailed contents of the information on eNB-to-eNB interference

• Any new backhaul signaling capturing eNB-to-eNB interference shall be assumed not to:

– impose mandatory behaviour in the receiving eNB

– impose new requirements on the accuracy of eNB measurements (unless shown to

be beneficial)

– impose new architecture for LTE

Note that this does not preclude consideration in RAN1 of any feedback from RAN4.

另外，關於重新組態訊號通知，此次會議最大的爭議在於是否要使用

23

PBCH/MIB 來進行直接式或者間接式的通知。詳細的決議如下：

7.2.3.2 Signalling mechanisms for TDD UL-DL reconfiguration

Agreement:

• No new TDD UL-DL configurations are introduced in the BCT (in WI on TDD eIMTA)

• Alternative 1 below is agreed.

Note: “PHY signaling” includes possibility of

UE specific or UE common signaling

Using either existing or newly defined DCI formats

Alternative 1:

• A signaling mechanism which explicitly or implicitly indicates TDD UL-DL

reconfiguration by either

• PHY signaling (not including PBCH/MIB signaling), or

• MAC signaling

• PBCH/MIB signaling issue could be revisited if reliability issue of the above method

becomes severe

Support: Renesas Mobile Europe, RIM, Intel, Samsung, Nokia, NSN, Qualcomm, Sharp , NTT

DoCoMo, Potevio, NEC, Panasonic, LGE, Ericsson, ST-Ericsson, MediaTek, ITRI,

Interdigital,

Alternative 2:

• A signaling mechanism which explicitly or implicitly indicates TDD UL-DL

reconfiguration by either

• PHY signaling ( including PBCH/MIB signaling), or

• MAC signaling

Support: CATT, CMCC, CATR, New Postcom, Coolpad, Alcatel Lucent, ASB, ZTE,

Huawei, Hi Silicon

6. Device to Device Communications

根據上個會期的共識，本會期需要針對模擬情境進行討論，本會期主要工

作在於討論 General Scenario以及 Public Safety Scenario的模擬情境，並討論這

兩種情境的模擬設定。本會期針對模擬的佈建情境，載波頻率，頻寬，評估基

準等參數進行討論。根據目前的討論，有以下六種佈建情境：

24

Option 1: Urban macro (500m ISD) + {1} RRH/Indoor Hotzone per cell

Option 2: Urban macro (500m ISD) + {1} Dual stripe per cell

Option 3: Urban macro (500m ISD) -- all UEs outdoor

Option 4: Urban macro (500m ISD) + {3} RRH/Indoor Hotzone per cell

Option 5: Urban macro (1732m ISD) (UE dropping details FFS)

Option 6: Urban micro (100m ISD)

根據會場討論，目前根據兩種情形進行投票表決，分成 General Scenario

跟 PS Specific scenario，並根據投票結果排出模擬的優先順序，投票結果如下：

o General Scenario

1: QC, USDoC, ALU, ASB, Fujitsu, GDB, CATT, NEC

2: Samsung, Nokia, NSN, RIM, Renesas,

3: ZTE, ITRI, EADS, E///, ST-E

4: LGE, Telecom Italia, Intel,

5:

6: HW, HiSi

o PS Specific scenario

1: QC, USDoC, GDB,

2:

3: ALU, ASB, Samsung, CATT, E///, ST-E, ZTE, VF, ITRI,

4

5: HW, HiSi, EADS, Fujitsu, NSN, Nokia, LGE, Nomor, NEC, Renesas

6

下表為目前 RAN1會議同意的模擬情境，該模擬情境還說明了在一般的情

境，載波中心頻率為 2GHz，在 PS Specific Scenario，中心頻率是 700MHz。對

於 General Scenario 來說，TDD 使用的 20MHz，FDD 使用的是 10MHz，對於

是否需要一個額外的頻率去表述 PS 的頻率，目前還在討論中。對於超出網路

覆蓋範圍的 UE，目前先討論以-6dB 為界去設定。目前主要是先假設在網路同

步的情境下去，但在非相同頻率的情況下，會錯開彼此間的頻率，亦即異頻下

網路是非同步狀態。用戶速度在 General Scenario 考慮為 3km/hr 的低速狀態，

在 PS Specific Scenario 考慮 120km/hr跟 3km/hr的混和速度狀態。

Property General Scenario PS Specific Scenario

25

Layout Option 1 (mandatory)

Others optional in order of

decreasing priority:

Option 2 / Option 3

Option 4

Option 6

Option 5 (mandatory)

Others optional in order of

decreasing priority:

Option 3

Option 1

Carrier

Frequency

(note that the

performance at 2GHz is

expected to be different

from the performance at

700MHz.)

2GHz 700 MHz

System

bandwidth

10MHz (FDD), 20 MHz

(TDD)

FFS whether an additional

bandwidth reflecting the

PS-specific scenario may

be added

FFS

Network

operation

100% eNBs enabled {0, x (FFS)}% eNodeB enabled

FFS whether disabled eNBs are

selected randomly or

deterministically

(Note that x may be 100%)

UE out of

coverage

criterion

Average SINR < {-x (-6dB working

assumption – can be revisited at

RAN1#73)} dB over system

bandwidth.

Network

synchronization

Mandatory:

- all eNodeBs synchronized

- eNodeBs on different carriers not synchronized

Optional: eNodeBs on a given carrier not synchronized

UE mobility {3,X} km/hr 120 km/hr for {x} fraction of

outdoor UEs

{3,X} km/hr for other UEs

UE RF

parameters

Max Tx power of 23 dBm for non PS -- 23 dBm, 31 dBm

for PS

1 Tx (2 Tx optional for PS only), 2 Rx antenna, Antenna gain 0

26

dBi, Noise figure 9 dB

UE inband

emission mask

FFS under what circumstances (if any) this is needed; if

needed, as per 36.101 s.6.5.2.3

eNodeB RF

parameters

As specified in 3GPP Case 1, except for Option 5 which uses

parameters as specified in 3GPP Case 3

Traffic models Full buffer, VoIP, & FTP2 from 36.814

Non D2D traffic With probability {X}, a D2D UE has non D2D (downlink &

uplink) traffic.

WAN traffic is FTP2

根據目前的討論，對於 unsynchronised network，Ericsson, ST-E, Telecom

Italia, Docomo, Vodafone, Deutsche Telekom, ALU, ASB, KDDI, NEC 等公司認為

是一定要考慮的情境，僅有 Qualcomm覺得這並非一定要考慮的情形。目前這

兩種情境人需要被討論。

根據 UE 的擺置，目前同的內容詳述於 R1-131789，請參考下表中，黃色

的部分為尚須討論並研究的內容。

General Scenarios Public Safety Scenarios

LTE Layout Option 1 (mandatory)

Others optional in order of

decreasing priority:

Option 2 / Option 3

Option 4

Option 6

Option 5 (mandatory)

Others optional in order of

decreasing priority:

Option 3

Option 1

Total number of

active UEs per cell

area

FFS

Starting point:

25 for options 1,2,4

10 for options 3,5,6

Number of D2D

UEs for discovery

FFS

Number of D2D

UEs for

communication

FFS

27

UE drop for all UEs, for

both discovery and

communication

evaluations

For Layout option 1,2, 4:- 2/3 UEs randomly and uniformly dropped within the clusters

of small cell(s), 1/3 UEs randomly and uniformly dropped throughout the macro

geographical area.

a) 20% UEs are outdoor and 80% UEs are indoor.

For Layout option 5, UEs randomly and uniformly dropped throughout the macro

geographical area; 20% UEs are outdoor and 80% UEs are indoor. Drop 2 RRH

buildings (without RRHs) in each macro geographical area.

For Layout option 3, 5, 6 –

a) Uniform drop - all UEs are randomly and uniformly dropped throughout the

macro geographical area

b) Hotspot drop – Randomly select an area within each macro geographical area.

Randomly and uniformly drop 2/3 UEs within 40 m of the selected area.

Randomly and uniformly drop the remaining 1/3 UEs to the entire macro

geographical area of the given macro cell

UE association for

unicast D2D

communication

Random pairing: First UE is randomly selected from all UEs within entire 19/7 macro

sites and 2nd

UE is randomly selected from the remaining UEs within entire 19/7 macro

sites

2nd

UE will be re-selected with constraint of minimum RSRP between two UEs if RSRP

is less than X dBm (FFS; in the meantime, companies may choose the value, including

- ) when UE is transmitted at maximum power

UE association for group

cast D2D communication

N/A Random pairing: First UE is randomly

selected as the UE for group cast from all

UEs within entire 19/7 macro sites

All Y number of receiving UEs are

randomly selected from the remaining UEs

within entire 19/7 macro sites

FFS-Number of receiver UEs “Y”

UEs will be re-selected with

constraint of minimum RSRP between two

UEs if the RSRP is less than X dBm (FFS;

in the meantime, companies may choose

the value, including - ) when UEs are

28

transmitted at maximum power

UE association for

broadcast D2D

communication

N/A Random pairing: First UE is randomly

selected as the UE for group cast from all

UEs within entire 19/7 macro sites

All Y number of receivier UEs are

randomly selected from the remaining UEs

within entire 19/7 macro sites

FFS: Number of receiver UEs “Y”

UE will be re-selected with constraint

of minimum RSRP between two UEs if the

RSRP is less than X dBm (FFS; in the

meantime, companies may choose the

value, including - ) when UE is

transmitted at maximum power

UE association for Relay

D2D communication

N/A First UE is randomly selected from all UEs

without eNB coverage and 2nd

UE is

selected from the UEs within eNB coverage

Minimum distance

between UE and eNB

>=35m (except for Option 6…)

Minimum distance

between UEs

>= 3m

以下兩個表格所列，說明 D2D的 Discovery與 Communications 效能指標，

討論 Discovery與 Communications 兩種情境。

Discovery效能指標

Aspect Metrics*

Performance

target

Open discovery:

- Number of UEs discovered as a function of time

(system)

- CDF of number of UEs discovered as a function of

time (system)

Closed discovery (i.e. knowing the UEs to be discovered):

- Probability of discovery as a function of time

29

(assume zero time penalty for each false alarm)

(Time measured from start of simulation without prior

synchronisation)

Range &

reliability

Prob. of discovery vs pathloss (link & system)

Prob. of false alarm (link & system)

Impact on

WAN

Amount of resource used (system) (per cell if in network

coverage)

FFS metrics related to throughput loss and/or interference

Power Power consumption modeled through ON time or equivalent

power consumed (transmit power should be captured

differently than received power --detailed model FFS)

*Same metrics used for in-network, partial network and out of network with possible different

emphasis

*Same metrics used for public safety and non-public safety cases with possible different emphasis.

Communications 效能指標

Aspect Metrics*

D2D Throughput

/spectral efficiency

User throughput (mean, 5%, CDF) for full buffer

(system) Perceived user throughput (mean, 5%, CDF)

for FTP (system)

VOIP system capacity (system) (VOIP delay

requirement {X}ms)

Range and

Reliability

Performance** vs pathloss or distance (link and

system)

For link level, use only full buffer

Call setup latency Phy. layer latency for call setup for out of coverage

only (link and system)

(This should only model L1 related aspects; higher

layer aspects should be considered in RAN2)

Impact on WAN Change in cell throughput/cell spectral efficiency

(system)

Cdfs of perceived per-user throughput for FTP2 with

and without D2D

Power

consumption

Power consumption should be modelled; detailed

model is FFS

*Same metrics used for in-network, partial network and out of network

*Same metrics used for public safety and non-public safety cases with possible different emphasis.

*Same metrics used for unicast, groupcast and broadcast with each receiver counted separately

30

** Performance means throughput, perceived throughput, prob. of satisfied VOIP user depending

on traffic model

7. Low-cost MTC

本會期針對 Low-cost MTC為了提供額外 20dB對每個通道做出了討論，針

對每個通道，從放開效能需求，到從新設計有了許多的討論。

PSS/SSS

同意事項如下：

• The coverage enhancement requirement for PSS/SSS can be achieved by longer acquisition

time

– Initial synchronization requires up to 2 seconds for FDD per a center carrier

frequency

– Re-synchronization can be performed quicker

• PSD boosting can be considered a complementary solution

• New PSS/SSS design may need to be considered if the longer time and freq. acquisition

and associated power consumption increase are not considered acceptable

• In addition to coverage enh. analysis, TP should include followings for all channel/signals

– Impact on specification

– Other impacts

• Power consumption

• Cell spectral efficiency

• Analysis/evaluation of cost reduction

PBCH

同意事項如下：

• The coverage requirement for PBCH may be met with a combination of repetition of the

current PBCH in each subframe and PSD boosting (e.g., 4dB) within 40ms (for FDD

systems)

– Repetition alone cannot meet the coverage requirement for the current PBCH

• The coverage requirement for PBCH may alternatively be met with a new PBCH design

(for TDD and FDD systems)

– A new design can consider: a longer period, reduced MIB content, intermittent

transmission. Repetitions and/or PSD boosting will be helpful for new design to

meet the requirement

31

– Also other system information that needs to be broadcasted to enhanced coverage

MTC UEs beside MIB contents can be considered in the new PBCH design

– Other low rate coding schemes or spreading can be considered for new design

• Further study could determine if there is a benefit of

– Using implementation-based solution such as new decoding techniques

PRACH

同意事項如下：

• The coverage requirement of PRACH can be achieved by preamble repetition and/or new

preamble format

– PRACH resources for coverage limited MTC UEs need to be defined and allocated

• Relaxing PRACH miss probability will make it easier to meet the coverage requirement,

and can be used in addition to repetition and/or new preamble format for PRACH coverage

improvement

• System impacts should be clarified including collision probability increase, PRACH

latency increase

• As a complement to the other techniques, PSD boosting over a narrower bandwidth may be

considered

Note:

・ Include RAN1 #72 following observation of PRACH in TP

PRACH can be used to inform eNB the amount of coverage enhancement a low cost

MTC UE needs

Observations:

• Coverage enhancement must be provided for scenarios where no small cells are deployed

• An operator may decide to deploy additional macro or LPN sites to achieve a coverage

benefit

• For deployments that already contain small cells, there may be a benefit to allow decoupled

UL and DL for delay tolerant MTC UEs

同意事項如下：

• A section is added to 9.4 to capture the above observations on the technique of using small

cells

32

• Email discussion can also discuss details of the proposal, and additional text that could be

added to the PRACH section

PDSCH

同意事項如下：

• The coverage requirements for PDSCH can be met by time domain repetition

– Cross-subframe channel estimation requires less number of repetition times than

single-subfame channel estimation

• RS power boosting and/or increased RS density may further improve the channel

estimation performance

• PSD boosting for PDSCH can help to improve the coverage

PUSCH

同意事項如下：

• PUSCH coverage enhancement requirement for MTC UE can be achieved by repetition

– Channel estimation over multiple subframes could be helpful to reduce the number

of repetitions

– Nevertheless, compared to PDSCH case, relatively larger number of repetitions

would be required for the PUSCH coverage

– Selection of TBS needs to consider the spectral efficiency and channel coding gain

• Complementary schemes can be considered to reduce the number of repetitions, for

example

– Increased DMRS density

– PSD boosting

– Frequency hopping during repetition

– Shorter length CRC

– Code spreading

• Companies may bring potential PUSCH performance issues at the next meeting

(E)PDCCH

同意事項如下：

• Repetition of (E)PDCCH across multiple subframes is required to achieve the coverage

enhancement target

33

– Specification impact may exist, such as starting subframe of first transmission, the

maximum number of repetitions, timing relationship between PDSCH and

(E)PDCCH

• PSD boosting can help to reduce the required number of repetition

• The new design of downlink control channel, for example compact DCI, higher

aggregation level, can help to reduce the required number of repetition

• Note that control overhead should be considered for further analysis in the potential WI

phase, concerning the overall system efficiency optimization

PUCCH

同意事項如下：

• The coverage requirements for PUCCH format 1a can be met with time domain repetition

• Further evaluation could show whether the following contents could be reduced or

eliminated

• SR

• CSI

• HARQ-ACK

8. Small Cell Discovery

針對 Small Cell Discovery，本次會期主要針對如何辨識 Small Cell進行討

論，目前有三種方案，第一種方案是根據同步通道來設計，第二種方案是將傳

統的同步通道跟參考信號作修改，第三種方案是設計新的 Discovery 通道去支

援 Small Cell Discovery。目前有多個需求如下：

• Requirements

– Requirement 1: To minimize UE battery consumption for discovery

– Requirement 2: To solve PCI confusion/collision

– Requirement 3: To detect sufficient number of cells

• FFS: actual target number of cells

– Requirement 4: To support detection between small cells

– Requirement 5: To support DTX small cell operation

– [FFS] Requirement 6: To have a commonality with D2D discovery

本會期同意內容如下：

34

- Metrics for evaluation:

o UE battery consumption for discovery

o Number of supportable individually identifiable small cells

Baseline is current number of supported PCIDs

Identify whether the current number is sufficient

o Number of detectable cells in the chosen scenarios

Target FFS for each scenario (or for a given SINR)

Target false alarm probability FFS

Detectability as defined in 36.133 for initial evaluation

o Probability of detecting a cell as a function of distance

o Detection time (e.g. taking into account ability to support small cell DTX operation

/ energy consumption)

o Ability to estimate the signal strength of a small cell

o Overhead

o Impact on legacy UEs

- Begin by evaluating performance of legacy mechanism (i.e. PSS/SSS/CRS)

- If inadequacies are identified with the legacy mechanism, evaluate:

o first, approaches based on modified SS/RS

o second, approaches based on new discovery signal

- Evaluation methodology:

o Up to companies to decide between e.g.:

Alt.1:

Step-0:system level simulation to model the interference profile for

link level simulation

Step-1: link level simulation to derive the performance curve (i.e.,

SINR – detection probability) based on the interference profile

derived by the Step-0 simulation

[FFS] Step-2: system level simulation based on LLS to SLS

mapping

Alt.2: System level evaluation including link-level signal generation and

detection

- Scenario:

o Scenario 2a with dense deployment of small cells

Baseline: 1 cluster per cell, 10 cells per cluster; other values can also be

evaluated.

- Synchronisation cases (in order of decreasing priority):

o 1: Synchronized transmission of discovery signal both within and between clusters

in the same or different macro cells

35

o 2: Synchronized transmission of discovery signal within clusters; unsynchronized

between clusters

o 3: Unsynchronized

o FFS: Level of synchronization (including timing offset between cells)

Resolve FFSs at RAN1#73.

9. WLAN/3GPP Radio Interworking (Rel-12) 議題

36

七、心得與建議

本團隊在這次會議中關注多個 Rel-12的新興技術議題。以下為此次會議後

本團隊對於這幾個技術項目的心得：

Further Downlink MIMO Enhancement

DL MIMO enhancements 針對 4-TX設計了新的 codebook以因應不

同天線架構，並新增 PUSCH feedback mode 3-2以改善效能，相關

的模擬平台應開始著手以助於評估各項 MIMO 技術能帶來的系統

增益。

Study on Elevation Beamforming and FD-MIMO

該 Study Item需要定義新的 3D通道模型，這也是目前會議在該項

目中的討論重點之一。應持續開發 spatial channel model 的模擬平

台，並與將來新的 3D 通道模型進一步整合。

Network-Assisted Interference Cancellation (NAIC)

繼續掌控此項研究議程的進行方向並繼續做出貢獻，幫忙模擬各種

情境，評估此項技術的可行性

可參考 RAN4的初步接收器評估

開始著手了解各種不同的接收器，並且將其效應於系統層模型化，

可於下幾次會期在會議提供簡單而不失準確性的模型

盡量以可以直接反應在 SINR上的模型為主

Further Enhancements to LTE TDD for DL-UL Interference Management

and Traffic Adaptation

此次會議著重於討論分時多工系統增強干擾消除和流量調整議題

(TDD eIMTA)的信號通知方式，目前結論為偏好能夠支持快速變換

重新組態的信號機制，例如透過 PHY或 MAC來通知 Rel-12 UEs，

以達到較好的干擾消除和流量調整效能。此外未來也將會繼續討論

信號為直接通知(explicit)或間接通知(implicit)給 Rel-12 UEs。

目前為初步的討論信號傳送機制，未來將有許多衍生議題需要我們

參與共同探討，例如分時多工系統增強干擾消除和流量調整議題

(TDD eIMTA)的 HARQ-ACK和 DCI detection timeline。

37

本次會期在 Device to Device有許多的討論，由於上個 Plenary會期決議

將 Device to Device的解決方案提前到五月會期開始，因此本會期針對

模擬情境、效能指標作了討論，因此會場針對 Device to Device的討論

是升溫的。