Dong In Kim (SKKU, Korea), Director of CWC-ITRC

Funded by Ministry of Science, ICT & Future Planning, Korea

Shared/Amorphous Cell

not clearly defined!!

2

Cooperative Wireless Communications Research Center

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Generalized Cell Association

3

Heterogeneity increases the degree of asymmetry

High power node vs. small power node

Outdoor channel vs. indoor channel

Ideal backhaul vs. non-ideal backhaul

Asymmetric traffic in uplink/downlink

Dynamic TDD in uplink/downlink

Range Expansion offload macro-cell traffic to small cells

Enhanced uplink data rates

Increased capacity

Improved robustness

Cooperative Wireless Communications Research Center

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Range Expansion [A]

4

[A] S. Parkvall, E. Dahlman, G. Jöngren, S. Landström, and L. Lindbom, “Heterogeneous Network Deployments in LTE - The soft-cell approach,” Ericsson Review, 2011.

Rx power(path loss) -1

Low-power node

Macro cell

Downlink-signal-strength cell border

Path-loss-based cell border

Cooperative Wireless Communications Research Center

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Shared/Amorphous Cell

5

Soft Cell allows for dual connection

Cell-specific RS (CRS) based system information

Demodulation-specific RS (DM-RS) based data transmission

Transmission point is transparent to the receiving UE device

Multiple small cells can reuse time/frequency resources

Over-the-air combining from macro and small cells

Phantom Cell frequency-separated small cells

C-plane/U-plane split configuration (master-slave relationship)

C-plane supported by reliable macro-cell layer at lower frequency

U-plane provided by high capacity small cells at higher frequency

Need new carrier type with no CRS (not conventional “cell”)

Need new X3 interface (non-ideal backhaul)

Cooperative Wireless Communications Research Center

COOP-Wireless

Soft Cell [A]

6

[A] S. Parkvall, E. Dahlman, G. Jöngren, S. Landström, and L. Lindbom, “Heterogeneous Network Deployments in LTE - The soft-cell approach,” Ericsson Review, 2011.

Same PSS/SSS,BCH,CRS

13 2

Data (PDSCH)Control (PDCCH)

Cooperative Wireless Communications Research Center

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Phantom Cell [B]

7

[B] H. Ishii, Y. Kishiyama, and H. Takahashi, “A Novel Architecture for LTE-B - C-plane/U-plane Split and Phantom Cell Concept,” IEEE GLOBECOM 2012 Workshop on Emerging Technologies for LTE-Advanced and Beyond-4G, Dec. 2012.

Super high traffic area

Normal high traffic spot

Cooperative Wireless Communications Research Center

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Phantom Cell [B]

8

C-plane

U-plane

Macro cell(low frequency)

Phantom cell(high frequency)

SPLIT!!!

＂New Interface＂(Non-Ideal Backhaul)

[B] H. Ishii, Y. Kishiyama, and H. Takahashi, “A Novel Architecture for LTE-B - C-plane/U-plane Split and Phantom Cell Concept,” IEEE GLOBECOM 2012 Workshop on Emerging Technologies for LTE-Advanced and Beyond-4G, Dec. 2012.

Vision for 5G

9

Cooperative Wireless Communications Research Center

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Features of 5G Wireless Cellular

10

1000 times higher traffic volumes than 2010 traffic levels

10 Gbps and 100 Mbps peak and cell-edge rates

Lower latency less than 1ms for local area networks

Enhanced Small Cells heterogeneous deployment

Aggregate capacity in both licensed/unlicensed spectrum

Cognitive Small Cells deployment [1]

Generalized Cell Association via spectrum sensing

Self-Organizing Networks (SONs)

Millimeter-wave Mobile Broadband (MMB)

[1] H. EISawy, E. Hossain, and D. I. Kim, “HetNets with Cognitive Small Cells: User Offloading and

Distributed Channel Access Techniques,” IEEE Commun. Mag., vol. 51, pp. 28-36, June 2013.

Cooperative Wireless Communications Research Center

COOP-Wireless

Cognitive Small Cells

11

[1] H. EISawy, E. Hossain, and D. I. Kim, “HetNets with Cognitive Small Cells: User Offloading and Distributed Channel Access Techniques,” IEEE Commun. Mag., vol. 51, pp. 28-36, June 2013.

User Offloading Techniques [1]

, ,

1. Small Cell association probability is defined by

- biasing paremeter for small cell

S tx s s s tx m m mP P P Th r P h r

T

2/

,

,

2. Cell association probability is much more sensitive to

change in density than to change in transmit power,

which can be controlled via the ratio

tx ss

m tx m

P T

P

Cooperative Wireless Communications Research Center

COOP-Wireless

Cognitive Small Cells

12

[1] H. EISawy, E. Hossain, and D. I. Kim, “HetNets with Cognitive Small Cells: User Offloading and Distributed Channel Access Techniques,” IEEE Commun. Mag., vol. 51, pp. 28-36, June 2013.

User Offloading Techniques [1]

Cooperative Wireless Communications Research Center

COOP-Wireless

Cognitive Small Cells

13

[1] H. EISawy, E. Hossain, and D. I. Kim, “HetNets with Cognitive Small Cells: User Offloading and Distributed Channel Access Techniques,” IEEE Commun. Mag., vol. 51, pp. 28-36, June 2013.

Distributed Channel Access via spectrum sensing [1]

1. Contention-resolution-based channel access (scheme 1)

2. Uncoordinated aggressive channel access (scheme 2)

1 opportunistic access opportunistic accessoutP P P SINR P

1

Minimum Frequency Reuse Distance

( , )

- path loss exponent

- spectrum sensing threshold

txe

P h x yr

Cooperative Wireless Communications Research Center

COOP-Wireless

Cognitive Small Cells

14

[1] H. EISawy, E. Hossain, and D. I. Kim, “HetNets with Cognitive Small Cells: User Offloading and Distributed Channel Access Techniques,” IEEE Commun. Mag., vol. 51, pp. 28-36, June 2013.

Distributed Channel Access via spectrum sensing [1]

Cooperative Wireless Communications Research Center

COOP-Wireless

Cognitive Small Cells

15

[2] A. Abdelnasser, E. Hossain, and D. I. Kim, “Clustering and Resource Allocation for Dense Femtocells in a Two-Tier Cellular OFDMA Network,” revised, IEEE Trans. Wireless Commun., Oct. 2013.

Clustering and Hierarchical Interference Management [2]

Optimize the trade-off between co-tier interference and the share in the available spectrum, which depends on the cluster size!

UE UE UE

eNodeB for RRHs

Ideal backhaulMacro cell(RRH)

Small cell

Non-idealbackhaul

Non-idealbackhaul

Small Cell Cluster(like TPs in CoMP scenario 4)

Small cell (RRH)

Idealbackhaul

eNodeB for RRHs

Non-ideal backhaul

To Macro eNB

E.g. Small hot spot, Indoor, ...

E.g. Train station, Shopping mall, Stadium, ... E.g. City square, City street, ...

Big Small Cell Cluster(like TPs in CoMP scenario 4)

F1

F2

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Cognitive Small Cells

16

[2] A. Abdelnasser, E. Hossain, and D. I. Kim, “Clustering and Resource Allocation for Dense Femtocells in a Two-Tier Cellular OFDMA Network,” revised, IEEE Trans. Wireless Commun., Oct. 2013.

Clustering and Hierarchical Interference Management [2]

1. Small Cell Gateway (SGW) is responsible for clustering, where correlation clustering is used as a method for small cell grouping.

2. For a given cluster configuration, within each cluster, one small cell (RRH) is elected as a Cluster Head (CH) that is responsible for

resource allocation among the small cells in that cluster.

Optimal Clustering results from the cluster configuration yielding the highest data rate!

Cooperative Wireless Communications Research Center

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Cognitive Small Cells

17

[2] A. Abdelnasser, E. Hossain, and D. I. Kim, “Clustering and Resource Allocation for Dense Femtocells in a Two-Tier Cellular OFDMA Network,” revised, IEEE Trans. Wireless Commun., Oct. 2013.

Clustering and Hierarchical Interference Management [2]

Cluster SizeAdaptation

Large-scale Aggregate Interference

Inter-Cluster Control

Small-scale Opportunistic Spectrum

Access within Cluster

Semi-distributedCognitive Small Cells

Cooperative Wireless Communications Research Center

COOP-Wireless

Millimeter-wave Mobile Broadband

18

Hybrid of MMB + 4G System [C]

Bridge the gap between better cell-edge performance (MMB) and network reliability (4G), leading to Amorphous Cell!

[C] Z. Pi and F. Khan, “System Design and Network Architecture for a Millimeter-wave Mobile Broadband (MMB) System,” IEEE 34th Sarnoff Symposium, pp. 1-6, Princeton, NJ, May 2011.

MBS_1 MBS_2

MBS_0

MBS_3

MBS_4

MBS_5 MBS_6

MBS_7

MBS_8MBS_9

MBS_10

MBS_11

MBS_12 MBS_14

MBS_13

Network

Cellular Base Station (CBS)

MMB Base Station (MBS)

cellular communication link

MMB communication link

Fixed line between MBS and CBS

Fixed line between CBS / MBS and packet Data Server / Gateway

Cooperative Wireless Communications Research Center

COOP-Wireless

Current Research Activities (1)

19

Cognitive Small Cells & Joint Clustering

[1] H. EISawy, E. Hossain, and D. I. Kim, “HetNets with Cognitive Small Cells: User Offloading and Distributed Channel Access Techniques,” IEEE Commun. Mag., vol. 51, pp. 28-36, June 2013.

[2] A. Abdelnasser, E. Hossain, and D. I. Kim, “Clustering and Resource Allocation for Dense Femtocells in a Two-Tier Cellular OFDMA Network,” revised, IEEE Trans. Wireless Commun., Oct. 2013.

[3] N. Saquib, E. Hossain, L. B. Le, and D. I. Kim, “Interference Management in OFDMA Femtocell Networks: Issues and Approaches,” IEEE Wireless Commun., vol. 19, pp. 86-95, June 2012.

Cooperative Wireless Communications Research Center

COOP-Wireless

Current Research Activities (2)

20

Hierarchical Power Control & Interference Management

[4] S. Guruacharya, D. Niyato, D. I. Kim, and E. Hossain, “Hierarchical Competition for Downlink Power Allocation in OFDMA Femtocell Networks,” IEEE Trans. Wireless Commun., vol. 12, pp. 1543-1553, Apr. 2013.

[5] D. I. Kim, E.-H. Shin, and M. S. Jin, “Hierarchical Power Control with Interference Allowance for Uplink Transmission in Heterogeneous Networks,” revised, IEEE Trans. Vehic. Technol., Aug. 2013.

[6] D. I. Kim, H. C. Moon, S. W. An, J. S. Han, S. Chae, and M. S. Jin, “Apparatus and Method for Cluster Based Opportunistic Power Control in Wireless Communication System,” US Patent Application No. 13/289,427 filed on Nov. 4, 2011. (Publication Date May 10, 2012) *This patent led to LTE Standard Proposal 3GPP R1-106052 for HetNet.

Cooperative Wireless Communications Research Center

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Current Research Activities (3)

21

Network MIMO in Small Cell Networks & D2D

[7] S. Guruacharya, D. Niyato, M. Bennis, and D. I. Kim, “Dynamic Coalition Formation for Network MIMO in Small Cell Networks,” accepted for publication, IEEE Trans. Wireless Commun., July 2013.

[8] P. Phunchongharn, E. Hossain, and D. I. Kim, “Resource Allocation for Device-to-Device Communications Underlaying LTE-Advanced Networks,” IEEE Wireless Commun., vol. 20, pp. 91-100, Aug. 2013.

[9] M. Hasan, E. Hossain, and D. I. Kim, “Resource Allocation Under Channel Uncertainties for Relay-Aided Device-to-Device Communications Underlaying LTE-A Cellular Networks,” submitted, IEEE Trans. Wireless Commun., Sep. 2013.

Cooperative Wireless Communications Research Center

COOP-Wireless

Green Cooperative Communications

22

Network Densification for cell-splitting gain

Enhanced Small Cell approach increases cell capacity.

New Carrier Type (NCT) in high frequency bands

NCT supports Hierarchical Cell Structure (multi-tier small cells).

Generalized Cell Association under heterogeneity

Shared/Amorphous Cell guarantees varying QoS of green media.

Massive MIMO for Millimeter-wave Mobile Broadband (MMB)

Can be viewed as Potential Enabler for multi-tier small cells.

Machine-Type Communications (MTC) with D2D

Seamless integration of MTC for Scale-Free Wireless Network!

Thank you!