GHAZAL ROUHAFZAYSUPERVISED BYASSOC. PROF. DR. ERHAN A. İNCE

A NEW STRATEGY TO IMPROVE THE EFFICIENCY OF OBBP ALLOCATION ALGORITHM

REFERENCES

CONCLUSION & Future Works

SIMULATION RESULTS

OBBP VS MOBBP

BROADBAND WIRELESS CHANNEL

Subchannelization schemes

OFDM VS OFDMA

INTRODUCTIONINTRODUCTION

• Mobile WiMAX based on IEEE 802.16e is a broad band wireless access technology which has been widely accepted as the best solution for wireless broad band services.

Instead of using a single wide-band carrier, multiple narrow-band parallel subcarriers are used

OFDMA

Subchannels

The minimum frequency-time resource unit Slot

Several slots assigned to a Mobile Station Burst

IEEE802.16e Rectangular

subc

hann

els

t

WIMAX FRAME STRUCTURE

56

4

75

54

51

Unused Slots

THESIS DESCRIPTION

• Implementing Orientation Based Burst Packing algorithm

(OBBP)

• Introducing a new packing strategy in the third stage of

the OBBP frame packing algorithm (Modified OBBP)

• Comparison Between OBBP MOBBP, eOCSA for randomly

generated bursts

• Comparison Between OBBP MOBBP, eOCSA for Hata

channel model

REFERENCES

CONCLUSION & Future Works

SIMULATION RESULTS

OBBP VS MOBBP

BROADBAND WIRELESS CHANNEL

Subchannelization schemes

OFDM VS OFDMA

INTRODUCTION

OFDM VS OFDMA

Saving in Bandwidth

OVERLAPPED SPECTRUM OF SUBCARRIERS IN OFDM

𝐅𝐫𝐞𝐪𝐮𝐞𝐧𝐜𝐲

Overlapping subcarriers

MULTI-USER CONCEPT OF OFDMASu

bcha

nnel

s

OFDM Symbol n

OFDM Symbol n+1

OFDM Symbol n+2

User1

User2

User3

User4

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

𝑡

𝐀𝐦𝐩𝐥𝐢𝐭𝐮𝐝𝐞

Inter Symbol Interference (ISI)

EFFECT OF ISI

ISI is a form of distortion of a signal in which one symbol interferes with subsequent symbols.

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

OFDM Symbol

Guard Interval

Guard Interval

1 OFDM Symbol = L data symbols

T

T=L

OFDM SYMBOL Duration

Data SYMBOL Duration

APPLYING GUARD INTERVALS

ISI between OFDM symbols are

removedWhile >

𝜏𝜏

Cyclic prefix

APPLYING CYCLIC PREFIX

OFDM DATA SYMBOLS

COPY AND PASTE THE LAST V SYMBOLS

Subchannelization schemes

SUBCARRIER TYPES

Data: Useful data transmission

Pilot: Channel estimation & Synchronization

Null: Guard Intervals & DC

SUBCARRIER PERMUTATION MODES

Diversity (Distributed)FUSC

(Full Usage of Subchannels)

PUSC(Partial Usage of Subchannels)

Contiguous (Adjacent)AMC (Adaptive Modulation and Coding)

Downlink

The subcarriers are distributed over the entire spectrum

Subcarriers are from adjacent frequencies

DL-PUSC2 symbol=284 pilot &24 data subcarriers

DL-FUSC

48 data subcarriers

1- Pilot subcarriers

Constant Variable

BROADBAND WIRELESS CHANNEL

BROADBAND WIRELESS CHANNEL

Communication System Transmitter

Receiver

The variation of signal amplitude over frequency and time.

Fading

Pathloss Shadowing

Path loss means the reduction in power density of the signal as it passes through the wireless channel.

𝑷 𝒓=𝑷𝒕𝝀𝟐𝑮𝒕𝑮𝒓

(𝟒𝝅𝒅 )𝟐Frii’s formula

PATH LOSS

Received power at the receiver

Transmitted power,

Transmitter gain Receiver gain

COST HATA CHANNEL MODEL

Environments Path Loss Formulas

Urban PL= 46.3 +33.9 13.82 ) a+ (44.96.55)) +

a=3.2 4.79

OBBP VS MOBBP

Pre-packing Stage Main Packing Stage Packing remaining bursts

ORIENTATION BASED BURST PACKING (OBBP)

Pre-packing Stage

PRE-PACKING STAGE

Priority Sorting

OF Calculation

Constructing OF Matrix

Burst Adaptation

B=

𝒃𝟏+𝒃𝟐+𝒃𝟑+…+𝒃𝒏>𝑵𝒔𝒍𝒐𝒕𝒔

⨯14

𝑩′

𝐏𝐫𝐢𝐨𝐫𝐢𝐭𝐲 𝐒𝐨𝐫𝐭𝐢𝐧𝐠

𝐎𝐫𝐢𝐞𝐧𝐭𝐚𝐭𝐢𝐨𝐧𝐅𝐚𝐜𝐭𝐨𝐫 𝐂𝐚𝐥𝐜𝐮𝐥𝐚𝐭𝐢𝐨𝐧

𝐵′= {10 ,7,4,6,10,9,4,10 }

Divisors =

CONSTRUCTING OF MATRIX

OF_Matrix=

00000000010000000000900000000000000000007000000000600000000100000000000400000000600000010064010907604000

1

412

2

4

1×44×12×2

BURST ADAPTATIONRemoving bursts with OFs out of the frame range from the OF_Matrix.

DL-Subframe

80 𝑂𝐹= {1×80 ,2×40 ,4×20 ,5×16 ,8×10 ,10×8 ,16×5 ,20×4 ,   80×1 }60

BURST ADAPTATION67 𝑂𝐹= {1×67 ,  67×1 }

67 + 1 𝑂𝐹= {1×68 ,  2×34 , 4×17 ,17×4 ,34×2 ,68×1 }

CONSTRUCTING RP MATRIX

Rp_Matrix

0000000003000000000100000000000000000001000000000100000000300000000002000000001000000301203101102000

𝐵′= {10 ,7,4,6,10,9,4,10 }

Pre-packing Stage Main Packing Stage Packing remaining bursts

Main Packing Stage

ORIENTATION BASED BURST PACKING (OBBP)

MAIN PACKING STAGE

Packing set selection Packing Set Arrangement Packing Set Stuffing

PACKING SET SELECTION

00000000010000000000900000000000000000007000000000600000000100000000000400000000600000010064010907604000

4+6+7+9+10=36

𝟑𝟔𝟐𝟎 𝟒𝟔 𝟏𝟎 𝟔𝟕𝟎𝟗𝟏𝟎

PACKING SET SELECTION

{4, 6, 14, 18, 24, 32, 44, 50, 74, 76, 78} =

= {78, 76, 74, 50, 44, 32, 24, 18, 14, 6, 4}

𝐵max𝐿′ ={39 ,38 ,37,25 ,22 ,16 ,12 ,7 ,3 ,2 }÷𝟐

Finding the optimal subset of bursts

𝑩𝒎𝒂𝒙𝑳

′ ={𝟑𝟗 ,𝟑𝟖 ,𝟑𝟕 ,𝟐𝟓 ,𝟐𝟐 ,𝟏𝟔 ,𝟏𝟐 ,𝟕 ,𝟑 ,𝟐 }

{38, 22}

{37, 16, 7}

{39, 12, 7, 2}

60

60

60

All elements in OF_Matrix

with the values equal to 38 and

22 will be set to zero.

If the corresponding element in Rp Matrix is equal to 1

Else corresponding element in Rp Matrix will be reduced by 1

𝟔𝟎

𝑩𝒎𝒂𝒙𝑳

′ ={𝟑𝟗 ,𝟑𝟖 ,𝟑𝟕 ,𝟐𝟓 ,𝟐𝟐 ,𝟏𝟔 ,𝟏𝟐 ,𝟕 ,𝟑 ,𝟐 }

38

22

PACKING SET ARRANGEMENT

Calculating sum of each group

Rearranging them in descending order based on their sums.

PACKING SET STUFFING

We start packing bursts from the bottom-right corner of the subframe.

ORIENTATION BASED BURST PACKING (OBBP)

Pre-packing Stage Main Packing Stage Packing remaining bursts

Packing remaining

bursts

PACKING REMAINING BURSTS

Sorting remaining bursts in descending order

Dividing unallocated slots into rectangles with its maximum possible dimension.

Choosing the suitable rectangle for the burst

Fitting the burst in the selected rectangle.

𝟕𝟕 {𝟏×𝟕𝟕 ,𝟕×𝟏𝟏 ,𝟏𝟏×𝟕 ,𝟕𝟕×𝟏   }

𝐀𝐯𝐚𝐢𝐥𝐚𝐛𝐥𝐞𝐫𝐞𝐜𝐭𝐚𝐧𝐠𝐥𝐞𝐬17

4060

OBBP algorithm drops the burst

MOBBP 𝟕𝟕+𝟏=𝟕𝟖{𝟏×𝟕𝟖 ,𝟐×𝟑𝟒 ,𝟑×𝟐𝟔 ,𝟔×𝟏𝟑 ,𝟏×𝟕𝟖 ,𝟏𝟑×𝟔 ,𝟐𝟔×𝟑 ,𝟕𝟖×𝟏}

eOCSA

SIMULATION RESULTS

[77 63 21]

2 4 6 8 10 12 14

10

20

30

40

50

60

DL Subframe

Symbols

Sub

chan

nels

Slots

OBBP[77 63 21]

MOBBP[77 63 21]

78 64

𝜼𝒑𝒌=𝑺𝒕𝒐𝒕𝒂𝒍−𝑺𝒑𝒂𝒅𝒅𝒆𝒅

𝑺𝒕𝒐𝒕𝒂𝒍

SIMULATION RESULTS

Packing Efficiency

BSR(Burst Size Ratio)

𝐵𝑆𝑅=𝐵𝑠𝑚𝑎𝑙𝑙

𝐵𝑙𝑎𝑟𝑔𝑒50%

𝑩𝒕𝒉 20

RANDOMLY GENERATED BURSTS

Burst sizes are randomly generated in the range [2, 95].

0.8 1 1.2 1.4 1.6 1.8 278

80

82

84

86

88

90

92

94

96

98

Offered Load

Pac

king

Effi

cien

cy

OBBP VS MOBBP

OBBPMOBBP

0.8 1 1.2 1.4 1.6 1.8 21

1.5

2

2.5

3

3.5

Offered Load

Pad

ded

Slo

tsOBBP VS MOBBP

OBBPMOBBP

COST-231 EXTENDED HATA CHANNEL MODEL

20 22 24 26 28 30 32 34 36 38 4070

75

80

85

90

95

100

Number of Users

Pac

king

Effi

cien

cy (%

)

OBBPMOBBPeOCSA

REFERENCES

CONCLUSION & Future Works

SIMULATION RESULTS

OBBP VS MOBBP

BROADBAND WIRELESS CHANNEL

Subchannelization schemes

OFDM VS OFDMA

INTRODUCTION

CONCLUSION & Future Works

• The efficiency of MOBBP algorithm is 1-3 percent better than

OBBP for randomly generated bursts and about 3-9 percent

for the realistic channel model.

• The efficiency of eOCSA is better than OBBP and MOBBP for

randomly generated bursts.

CONCLUSION

In the future in order to provide services with desired levels

of QoS we can work on a priority-aware version of MOBBP

algorithm which can give priority to allocation of bursts

based on latency constraints.

FUTURE WORKS

REFERENCES

CONCLUSION

SIMULATION RESULTS

OBBP VS MOBBP

BROADBAND WIRELESS CHANNEL

Subchannelization schemes

OFDM VS OFDMA

INTRODUCTION

References

References[1] L. Nuaymi, WiMAX Technology for Broadband Wireless Access, ENSTBretagne: John Wiley & Sons Ltd, 2007.[2] IEEE 802.16-2004, IEEE Standard for Local and metropolitan area networksPart 16: Air Interface for Fixed Broadband Wireless Access Systems, NewYork, 1 October 2004.[3] "Mobile WiMAX – Part I:A Technical Overview and Performance Evaluation,"WiMAX Forum, August, 2006.[4] J. G. Andrews, A. Ghosh, R. Muhamed, Fundamentals of WiMAXUnderstanding Broadband Wireless Networking, Westford, Massachusetts.:Prentice Hall, February 2007.[5] H. Schulze and C. Lueders, Theory and Applications of OFDM and CDMAWideband Wireless Communications, Meschede, Germany: John Wiley & SonsLtd., 2005.

[6] Y. S. Cho, J. Kim, W. Y. Yang, C. G. Kang, MIMO-OFDM WirelessCommunications With MATLAB, Clementi Loop, Singapore: John Wiley &Sons (Asia) Pte Ltd, 2010.[7] R. Prasad, OFDM for Wireless Communications Systems, Boston ,London:Artech House, Inc., 2004.[8] IEEE 802.16e,IEEE Standard for Air Interface for Broadband Wireless AccessSystems_Amendment 2: Higher Reliability Networks, Piscataway, 6 March2013.[9] D. Tse , P. Viswanath, Fundamentals of Wireless Communication, Cambridgeuniversity press, 2005.[10] M. Alshami, T. Arslan, J. Thompson and A. Erdogan, "Evaluation of Path LossModels at WiMAX Cell- edge," Edinburgh,Scotland, UK, 2011.[11] O. M. Eshanta, M. Ismail, and K. Jumari, "OBBP: An Efficient Burst PackingAlgorithm for IEEE802.16e Systems," International Scholarly ResearchNetwork ISRN Communications and Networking, Vol. 2011, Article ID 734297,,no. 10, pp. 1-9, 2011.

[12] C. So-In, R. Jain, A-K. A. Tamimi, "OCSA: An Algorithm for Burst Mapping inIEEE 802.16e Mobile WiMAX Networks1,2," in Proceedings of the 15th Asia-Pacific Conference on Communications (APCC 2009)-013, Oct., 2009.[13] C. So-In, R. Jain, and A-K. A. Tamimi, "eOCSA: An Algorithm for BurstMapping with Strict QoS Requirements in IEEE 802.16e Mobile WiMAXNetworks," 2009.[14] T-H. Lee, C-H. Liu, J. Yau and Y-W. Kuo, "Maximum Rectangle-BasedDown-Link Burst Allocation Algorithm for WiMAX Systems," in TENCON2011 , Bali, 2011.[15] K. Bahmani, E. A. Ince, D. Arifler, "Priority-Aware Downlink Frame PackingAlgorithm for OFDMA-Based Mobile Wireless Systems," in Signal Processingand Communications Applications Conference (SIU), 2013.[16] D. Alam and R. H. Khan, "Comparative Study of Path Loss Models of WiMAXat 2.5 GHz Frequency Band," International Journal of Future GenerationCommunication and Networking, Vols. 6, No. 2, p. 14, April, 2013.

[17] J. Vanderpypen and L. Schumacher, "Treemap-based Burst Mapping Algorithmfor Downlink Mobile WiMAX Systems," in Vehicular Technology Conference,2011.[18] R. Mardeni, T. S. Priya, "Optimised COST-231 Hata Models for WiMAX PathLoss Prediction in Suburban and Open Urban Environments," Modern AppliedScience, Vols. 4, No. 9, p. 15, September 2010.[19] D. Pareit, B. Lannoo, I. Moerman and P. Demeester, "The History of WiMAX:A Complete Survey of the Evolution in Certification and Standardization forIEEE 802.16 and WiMAX," IEEE Communications Survey & Tutorials, Vols.14, No.4, p. 29, Fourth quarter 2012.

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