Wireless Broadband Technologies Overview
INTRODUCTION
•
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
subchannels
t
56
4
75
54
51
Unused
Slots
•
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
OFDM VS OFDMA
Saving in
Bandwidth
Overlapping
subcarriers
Subchannels
OFDM
Symbol n
OFDM
Symbol n+1
OFDM
Symbol n+2
OFDM
Symbol
OFDM
Symbol
OFDM
Symbol
OFDM
Symbol
Inter Symbol
Interference (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
1 OFDM Symbol = L data symbols
T
OFDM SYMBOL
Duration
Data SYMBOL
Duration
Subchannelization schemes
Downlink
The subcarriers are distributed
over the entire spectrum
Subcarriers are from adjacent
frequencies
48 data
subcarriers
1- Pilot subcarriers
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.
Frii’s formula
Received power at the receiver
Transmitted power,
Transmitter gain
Receiver gain
OBBP VS MOBBP
OF_Matrix=
Removing bursts with OFs out of the frame range from the OF_Matrix.
80
67
4+6+7+9+10=36
{4, 6, 14, 18, 24, 32, 44, 50, 74, 76, 78}Finding the optimal subset of bursts
{38, 22}{37, 16, 7}{39, 12, 7, 2}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
38
22
Calculating sum of each group
Rearranging them in descending order
based on their sums.
We start packing bursts from the bottom-right
corner of the subframe.
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.
OBBP algorithm drops the burst
MOBBP
SIMULATION RESULTS
[77 63 21]
Slots
[77 63 21]
[77 63 21]
78
64
Packing
Efficiency
BSR
(Burst Size Ratio)
50%
20
Burst sizes are randomly generated in the range [2, 95].
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.
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.
References
[6] Y. S. Cho, J. Kim, W. Y. Yang, C. G. Kang,
MIMO-OFDM Wireless
Communications 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 Access
Systems_Amendment 2: Higher Reliability Networks,
Piscataway, 6 March
2013.
[9] D. Tse , P. Viswanath,
Fundamentals of Wireless Communication
, Cambridge
university press, 2005.
[10] M. Alshami, T. Arslan, J. Thompson and A. Erdogan, "
Evaluation of Path
Loss
Models at WiMAX Cell- edge,
" Edinburgh,Scotland, UK, 2011.
[11] O. M. Eshanta, M. Ismail, and K. Jumari, "OBBP: An Efficient Burst Packing
Algorithm for IEEE802.16e Systems,"
International Scholarly Research
Network 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 in
IEEE 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 Burst
Mapping with Strict QoS Requirements in IEEE 802.16e Mobile WiMAX
Networks," 2009.
[14] T-H. Lee, C-H. Liu, J. Yau and Y-W. Kuo, "Maximum Rectangle-Based
Down-Link Burst Allocation Algorithm for WiMAX Systems," in
TENCON
2011
, Bali, 2011.
[15] K. Bahmani, E. A. Ince, D. Arifler, "Priority-Aware Downlink Frame Packing
Algorithm for OFDMA-Based Mobile Wireless Systems," in
Signal Processing
and Communications Applications Conference (SIU)
, 2013.
[16] D. Alam and R. H. Khan, "Comparative Study of Path Loss Models of
WiMAX
at 2.5 GHz Frequency Band,"
International Journal of Future Generation
Communication and Networking,
Vols. 6, No. 2, p. 14, April, 2013.
[17] J. Vanderpypen and L. Schumacher, "Treemap-based Burst Mapping
Algorithm
for Downlink Mobile WiMAX Systems," in
Vehicular Technology
Conference
,
2011.
[18] R. Mardeni, T. S. Priya, "Optimised COST-231 Hata Models for
WiMAX Path
Loss Prediction in Suburban and Open Urban Environments,"
Modern
Applied
Science,
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
for
IEEE 802.16 and WiMAX,"
IEEE Communications Survey & Tutorials,
Vols.
14, No.4, p. 29, Fourth quarter 2012
.
Delve into the world of wireless broadband technologies with a focus on Mobile WiMAX based on IEEE 802.16e. Explore concepts like OFDM and OFDMA, subchannelization schemes, OBBP vs. MOBBP, simulation results, and more. Discover the implementation of the Orientation-Based Burst Packing algorithm and comparisons with other packing strategies. Gain insights into overlapping subcarriers, inter-symbol interference, and the use of subchannels in broadband wireless channels.
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Presentation Transcript
GHAZAL ROUHAFZAY SUPERVISED BY ASSOC. PROF. DR. ERHAN A. NCE
INTRODUCTION INTRODUCTION OFDM VS OFDMA Subchannelization schemes BROADBAND WIRELESS CHANNEL OBBP VS MOBBP SIMULATION RESULTS CONCLUSION & Future Works REFERENCES
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
subchannels t The minimum frequency-time resource unit Slot Several slots assigned to a Mobile Station Burst IEEE802.16e Rectangular
Unused Slots 4 51 54 56 75
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
INTRODUCTION OFDM VS OFDMA OFDM VS OFDMA Subchannelization schemes BROADBAND WIRELESS CHANNEL OBBP VS MOBBP SIMULATION RESULTS CONCLUSION & Future Works REFERENCES
Overlapping subcarriers ????????? Saving in Bandwidth
User1 User2 User3 User4 Subchannels OFDM Symbol n+1 OFDM Symbol n OFDM Symbol n+2
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 ? Inter Symbol Interference (ISI)
1 OFDM Symbol = L data symbols ISI between OFDM symbols are removed While ??> ? T=L?? OFDM SYMBOL Duration Data SYMBOL Duration T ? ? OFDM Symbol OFDM Symbol Symbol OFDM OFDM Symbol OFDM Symbol OFDM Symbol Guard Interval ?? Guard Interval ??
Cyclic prefix OFDM DATA SYMBOLS COPY AND PASTE THE LAST V SYMBOLS
INTRODUCTION OFDM VS OFDMA Subchannelization schemes Subchannelization schemes BROADBAND WIRELESS CHANNEL OBBP VS MOBBP SIMULATION RESULTS CONCLUSION & Future Works REFERENCES
Data: Useful data transmission Pilot: Channel estimation & Synchronization Null: Guard Intervals & DC
FUSC Diversity (Distributed) (Full Usage of Subchannels) Downlink PUSC The subcarriers are distributed over the entire spectrum (Partial Usage of Subchannels) AMC (Adaptive Modulation and Coding) Contiguous (Adjacent) Subcarriers are from adjacent frequencies
2 symbol ?? ???????????=28 4 pilot &24 data subcarriers
1- Pilot subcarriers 48 data subcarriers Constant Variable
INTRODUCTION OFDM VS OFDMA Subchannelization schemes BROADBAND WIRELESS CHANNEL BROADBAND WIRELESS CHANNEL OBBP VS MOBBP SIMULATION RESULTS CONCLUSION & Future Works REFERENCES
Transmitter Communication System Receiver The variation of signal amplitude over frequency and time. Fading Shadowing Pathloss
Path loss means the reduction in power density of the signal as it passes through the wireless channel. Transmitter gain Receiver gain ?????? ???? Frii s formula ??= ?? Transmitted power, Received power at the receiver
Environments Path Loss Formulas PL= 46.3 +33.9 log10? 13.82 log10( ?) a ?+ Urban (44.9 6.55log10( ?)) log10?+ ?? a ?=3.2(log10(11.75 ?))2 4.79
INTRODUCTION OFDM VS OFDMA Subchannelization schemes BROADBAND WIRELESS CHANNEL OBBP VS MOBBP OBBP VS MOBBP SIMULATION RESULTS CONCLUSION & Future Works REFERENCES
Packing remaining bursts Pre-packing Pre-packing Stage Stage Main Packing Stage
Priority Sorting OF Constructing OF Matrix Burst Calculation Adaptation
? ? ????? = 60 14 = 840 B= ??,??, ,??, ?? ??+ ??+ ??+ + ??> ??????
Divisors = ? = 1,2,,?? | ? ? ,??? ?? ,? = 0 ? = 10,7,4,6,10,9,4,10 1 7 ,7 1 1 4 ,2 2 ,4 1 1 6 ,2 3,3 2 ,6 1 1 10 ,2 5 ,5 2,10 1 1 9 ,9 1
2 4 1 0 0 0 4 0 6 7 0 9 10 1 1 4 4 1 2 2 0 4 6 0 10 0 0 0 0 0 2 0 6 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 4 0 10 0 0 0 0 0 0 0 0 OF_Matrix= 6 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0
Removing bursts with OFs out of the frame range from the OF_Matrix. DL DL- -Subframe Subframe 60 60 ?? ?? 80 80 = 1 80,2 40,4 20,5 16, 8 10,10 8,16 5,20 4, 80 1
?? = 1 67, 67 1 67 67 ?? 67 + 1 67 + 1 = ?? = 1 68, 2 34,4 17, 17 4,34 2,68 1
CONSTRUCTING CONSTRUCTING RP RP MATRIX MATRIX ? = 10,7,4,6,10,9,4,10 0 0 0 2 0 1 1 0 1 3 0 2 1 0 3 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 Rp_Matrix= 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0
Packing remaining bursts Main Packing Pre-packing Stage Main Packing Stage Stage
Packing set selection Packing Set Arrangement Packing Set Stuffing
0 0 0 4 0 6 7 0 9 10 0 4 6 0 10 0 0 0 0 0 4+6+7+9+10=36 0 6 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 0 7 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 ?? ?? ? ? ?? ? ? ? ? ??
???? = {4, 6, 14, 18, 24, 32, 44, 50, 74, 76, 78} ???? = {78, 76, 74, 50, 44, 32, 24, 18, 14, 6, 4} ? ?max_? = 39,38,37,25,22,16,12,7,3,2
Finding the optimal subset of bursts ????_? = ??,??,??,??,??,??,??,?,?,? 60 All elements in OF_Matrix with the values equal to 38 and 22 will be set to zero. {38, 22} 60 {37, 16, 7} 60 {39, 12, 7, 2} If the corresponding element in Rp Matrix is equal to 1 Else corresponding element in Rp Matrix will be reduced by 1
Calculating sum of each group Rearranging them in descending order based on their sums.
We start packing bursts from the bottom-right corner of the subframe.
Packing remaining Packing remaining bursts bursts Pre-packing Stage Main Packing Stage
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.
?? ? ??,? ??,?? ?,?? ? 1 ?? 7 ? ?? ? 40 ? 60 ? ????????? ?????????? OBBP algorithm drops the burst MOBBP ?? + ? = ?? ? ??,? ??,? ??,? ??,? ??,?? ?,?? ?,?? ?
INTRODUCTION OFDM VS OFDMA Subchannelization schemes BROADBAND WIRELESS CHANNEL OBBP VS MOBBP SIMULATION RESULTS SIMULATION RESULTS CONCLUSION & Future Works REFERENCES
[77 63 21] DL Subframe 10 20 Subchannels 30 40 50 60 2 4 6 8 10 12 14 Symbols Slots
[77 63 21] 78 64
