Proposal for Radio Resource Allocation using Dummy Burst Definition in IEEE 802.16 Uplinks

Takeo Ohseki and Takashi Inoue

Radio Access Laboratory, KDDI R&D Laboratories, Inc.

Ohara 2-1-15, Fujimino, Saitama, 356-8502, JAPAN

WCNC 2008

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Outline

Introduction IEEE 802.16 Systems Dummy Burst and Radio Resource Allocation

Method Considering Inter-cell Interference Numerical Analysis Conclusion

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Introduction

OFDMA is particularly anticipated in next-generation mobile networks multipath environments providing higher throughput and capacity considerable flexibility in managing spectrum

resources improved coverage

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Introduction

Uplinks of IEEE 802.16 OFDMA

PUSC

In PUSC mode Each subchannel, which consists of several sub

carriers, is allocated to a single user

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Introduction

BS allocates the uplink resource UL burst UL-MAP

The allocation of subchannels to users cannot be conducted flexibly without generating blank logical subchannels

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IEEE 802.16 SystemsA. OFDMA uplink subframe structure in IEEE 802.16

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IEEE 802.16 Systems B. OFDMA uplink subchannel permutation in IEEE 802.16

-Tiles(s, n) is the physical tile index in the FFT with tiles being ordered consecutively

-s is the subchannel number in the range 0 . . . Nsubchannels − 1

-n is the tile index 0 . . . 5 in a subchannel

-UL_PermBase is an integer value in the range 0 . . . 69

-Pt(·) is the tile permutation

-index(·, x) denotes the function that returns the x-th element

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceA. Introduction of Dummy Burst

In uplinks in the IEEE 802.16 system, data are initially allocated in bursts built on logical subchannels

A permutation of the tiles within a subchannel map tiles to physical subchannels

If there are some logical subchannels in a bad radio propagation environment, the bursts cannot avoid them

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceA. Introduction of Dummy Burst

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceB. Radio Resource Allocation using Dummy Burst

As regards interference between cells UL_PermBase

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceB. Radio Resource Allocation using Dummy Burst

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceB. Radio Resource Allocation using Dummy Burst

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceC. Requirements for realization

1) About changing UL_PermBase:

UL PermBase must be changed depending on traffic

In the IEEE 802.16 systems, A control message called Zone IE The dynamic change in the UL_PermBase can be reali

zed with the message transmitted by the BS

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceC. Requirements for realization

2) Concerning traffic detection:

The centralized control station to control multiple BSs is assumed

All the BSs regularly notify the centralized control station of the logical subchannels that they use.

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Dummy Burst and Radio Resource Allocation Method Considering Inter-cell InterferenceC. Requirements for realization

3) About a default value of UL PermBase:

When dummy bursts are inserted The same value of UL PermBase must be used betwe

en interfering cells

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Numerical AnalysisA. Ratio of interfering tiles

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Numerical AnalysisA. Ratio of interfering tiles

UL_Permbase = 0BS0

BS1

(BS1)

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Numerical AnalysisB. Throughput Performance

UL_Permbase = 0BS0

BS1

UL_Permbase = 2

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Numerical AnalysisB. Throughput Performance

proposed method

Subchannel<30

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Numerical AnalysisC. Discussion

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Conclusion

The authors proposed a novel concept for the definition of bursts in IEEE 802.16 uplinks Generating blank logical subchannels between used logical s

ubchannels in uplinks A radio resource allocation scheme successfully avoiding inte

rference between the cells based

Numerical analysis confirmed that Throughput performance can improve