inter-cell interference coordination in heterogeneous networks with open access of small cells

Toha Ardi Nugraha

WENS Laboratory

IT Convergence Engineering

Kumoh National Institute of Technology

Inter-Cell Interference Coordination in

Heterogeneous Networks with Open

Access of Small Cells

Wireless and Emerging Networking Siystem Laboratory

Toha Ardi Nugraha - IT Convergence Engineering- KIT

Inter-Cell Interference Coordination in Heterogeneous Networks with Open


Contents

•Introduction

•Problem Formulation

•Previous Works

•System Model

•Simulation Results

•Conclusion




Heterogeneous Networks

• Hetnets : different base station

types, (Macrocell/eNB) and low

power (Small-cells or home base

stations (HeNB)

• Macrocell : a wide area,

• low power Small-cells : hot-spots

and indoor (to offload traffic from

the Macro-layer)

Solution to boost the network

capacity and increase of data traffic




Small Cells

• Shift from voice-only to voice- & data-based traffic

• Improved technologies – smart antennas and

MIMO,

• Dead zone Problem – Poor indoor coverage

• Solution – Small Cells – (YouTube :

http://goo.gl/en8Gc8)

• What is small cells? improved cellular/indoor coverage, capacity and applications (ex : SON – Self Organizing Networks, plug and play)

• Type of small cells? Femtocells, picocells, metrocells and microcells

http://goo.gl/en8Gc8






Problem Formulation

• High density of small cells

• Problems :

Interference between small cells

• Solution??

Interference management : frequency

reuse and preceding technique (MMSE

and BD)

Small cell Small cell

Small cell Small cell

Poor Signal

Co-Channel Interference

(same frequency)

Small Cells

Small Cells

Small Cells




Access Method

Closed Access Open Access




Previous Works and Proposed Scheme

Parameter Previous Works Proposed

Multi Cell Non-Cooperative Cooperative Cooperative

(Clustering)

Scheme Frequency Reuse Precoding : MMSE Precoding : BD

Power Allocation Fractional Equal Power Water Filling

Bandwidth

Allocation

Frequency Reuse

(Weakness)

Full Bandwidth Full Bandwidth

Interference

Cancellation

Inter cell

interference

Inter user

interference

Inter user

interference

System Model

Precoding : Pre define symbol before transmitting




Interference cancelation in cooperative heterogeneous

Network with coordination strategy.

Contribution

• Coordination strategy in Heterogeneous Network,

consider :

– Extended Block Diagonalization scheme (Applied in

Heterogeneous Networks )

– Water filling power Allocation

– Open Acess Method

Proposed Scheme




Power Allocation

more power (low noise)

Equal Power Water filling

same power allocate to

each channel

Difference power

allocate to each channel

Problem : high

interference (power)

Give the more power

when the channel is

good




System Model Parameter Value

Number of small cells in cluster

2, 3, 4, 7

Number of neighbor cluster

1

Transmit Power of small cell

20 dBm/100 mW

Precoding MMSE and BD Frequency Reuse

Frequency Universal and Frequency Reuse

Workload Performance

• Number of Clustered Small Cells in Macrocells

• Power allocation

Sum rate capacity (data rate)




Sim

ula

tio

n R

esu

lt




Conclusions

• Proposed Interference Coordination in

Heterogeneous Networks

• Power allocations : water filling > equal power

allocation.

• Precoding : BD > MMSE

Thank You

Question?

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Kumoh National Institute of Technology

Thesis Presentation