1
Advisor: Dr. Kai-Wei Ke
Speaker: Ming-Chia Hsieh
Date: 30/07/2006
A Dynamic Uplink/Downlink BWA and Packet Scheduling Mechanism in WiMAX
2
Outline
Background WiMAX Standard Overview Proposed Architecture Simulation Conclusion
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WiMAX Overview
WiMAX? (Worldwide Interoperability for Microwave Access)
Wireless broadband network connection technique. Replace last mile. Cost saving Easy to deploy
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Basic WiMAX Network Architecture
Subscribe Station (SS)
Subscribe Station
Radio tow er
Wireless link
Radio tow er
Radio tow er
Radio tow er
Base Station (BS)
Subscribe Station
Core network
Wired/wireless links
Users
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Outline
Background WiMAX Standard Introduction
Frame Structure. Generic / Request Header Service Classes. QoS Procedure.
Proposed Architecture Simulation Conclusion
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Frame Structure
adaptive
Frame j Frame j+1Frame j-1
PS 0 PS N-1
Downlink Subframe Uplink Subframe
N = (Rate x Frame Duration) / 4
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Downlink subframe
Pream
ble
Broadcast ControlDIUC = 0
TDM DIUC a
TDM DIUC a
TDM DIUC a
Pream
ble
DL_MAP UL_MAP Transition Gap
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Uplink Subframe
Initial RangingOpportunities
(UIUC = 2)
RequestContention Op
ps(UIUC = 1)
SS 1Scheduled
Data (UIUC = i)
● ● ●
SSTGTransmit/Receive Transition Gap
Access Burst
Collision Collision
BW Request
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UL/DL MapFrame n-1 Frame n
DL-MAP
ATDD Split
DL-MAP
FrameControl
DownlinkSubframe
UplinkSubframe
UL-MAP UL-MAP
ATDD Split
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Outline
Background WiMAX Standard Introduction
Frame Structure. Generic / Request Header Service Classes. QoS Procedure.
Proposed Architecture Simulation Conclusion
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Rsv (1)
Generic MAC header
HT = 0(1)
EC(1) Type (6)
CI (1)
EKS(2)
Rsv (1)LENMSB(3)
LEN LSB (8) CID MSB(8)
HCS (8)CID LSB (8)
(#) number of bits
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Bandwidth request header formatH
T = 1 (1)
EC(1) Type (3) BR
MSB(11)
BR LSB (8) CID MSB(8)
CID LSB (8) HCS (8)
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Outline
Background WiMAX Standard Introduction
Frame Structure. Generic / Request Header Service Classes. QoS Procedure.
Proposed Architecture Simulation Conclusion
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Service Classes
UGSConstant bit rate , fixed packet length (ex. VoIP)
rtPSvariable bit rate , variable packet length (ex. MPEG)
nrtPSDelay tolerated (ex. FTP)
BEBest-Effort (ex. HTTP)
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Outline
Background WiMAX Standard Introduction
Frame Structure. Generic / Request Header Service Classes. QoS Architecture
Proposed Architecture Simulation Conclusion
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IEEE 802.16 QoS ArchitectureSubscriber Station (SS) Base Station (BS)
Application
Connection Classifier
UG
S
rtPS
nrtPS
BE
Admission Control(undefined by IEEE)
Connection Request
Connection Response
BW Request
Scheduler UL-MAP
Data Transmission
Uplink Packet Scheduling( UPS)
(Undefined by IEEE)
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IEEE 802.16 Procedures
BS SendUL/DL Map
BS SendDL Data
SSs SendBW requests
SSs SendUL Data
BS RunBWA
BS ReceivesBW Req.
SSs ReceiveUL/DL Map
SS ReceiveUL Data
BS ReceivesUL Data
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Outline
Background WiMAX Standard Introduction Proposed Architecture
Proposed Architecture. Request Maker Bandwidth Allocation Description Packet Scheduling Description
Simulation Conclusion
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Proposed QoS Architecture
Upstream
BS
Request DB
SSBW Request
BWA
MAP Generator Packet
Scheduler
DL/UL MAP
UGSrtPS
nrtPS
BE
Downstream
Classifie
r
Packet Scheduler
Request Maker
UG
S rtPS
nrtPS
BE
Classifier
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Problem & Solution of BWA
60 50 40 30 20 10
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Outline Background WiMAX Standard Introduction Proposed Algorithm
Proposed Architecture. Request Maker Bandwidth Allocation Description Packet Scheduling Description
Simulation Conclusion
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Request Maker
Request Maker
Connections
CID:001, BW: 100Kb
CID:002, BW: 150Kb
CID:005, BW: 50Kb
Bandwidth request messageSS
BS
Latency CID
60 001
70 003,005
100 002
CID:001, BW 50Kb
CID:002, BW 50Kb
CID:003, BW 50Kb
CID:004, BW 50Kb
CID:005, BW 50Kb
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Request Database
CID : 0011 (UGS)TotalNeeded 7000Kb TotalDelivery 3000Kb
Arrival Time 70 毫秒 100 毫秒 130 毫秒 140 毫秒
Deadline 130 毫秒 160 毫秒 190 毫秒 200 毫秒
Bandwidth 1000Kb 2000Kb 500Kb 1000Kb
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Outline Background WiMAX Standard Introduction Proposed Algorithm
Proposed Architecture. Request Maker Bandwidth Allocation Description Packet Scheduling Description
Simulation Conclusion Reference
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Bandwidth Allocation ProceduresDL
Emg(UGS)
UL Emg(UGS)
DL Emg(rtPS)
UL Emg(rtPS)
DLNEmg(UGS)
ULNEmg(UGS)
DLNEmg(rtPS)
ULNEmg(rtPS)
DLnrtPS
UL nrtPS
DL BE
UL BE
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BWA for Non-Real-time
Sort By Satisfaction rate. Allocate bandwidth from lower satisfaction
Total BW for nrtPS = 2/3 remaining bandwidth. Individual Station:
Min(Max_BW_For_nrtPS , nrtPS_Loading). Total BW for BE = remaining – nrtPS Individual Station:
Min(Max_BW_For_BE , BE_Loading).
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Outline
Background WiMAX Standard Introduction Proposed Algorithm
Proposed Architecture. Bandwidth Allocation Description Packet Scheduling Description
Performance evaluation
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Packet Scheduling
Restrict by the DL/UL Map Gets bandwidth of each Service Classes, and
pick packets in the HOL of the corresponding queue and sends at appropriated PS
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Outline
Background WiMAX Standard Introduction Proposed Algorithm Performance evaluation-via simulation Conclusion
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Environment Setting
Packets: Poison Arrival Connection: Poison Arrival Compare my algorithm to [3] which is
following the rules of spec. BW: 10Mbps BS: 1 , SS: 5 Queue: no limit length
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Drop Rate (UGS, rtPS)
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.5 0.6 1 1.3 1.5 1.7 1.9 2.2
Normalized Offered Load
Dro
p R
ate(
%)
Spec_UGS Spec_rtPS
Proporsed_UGS Proporsed_rtPS
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Drop Rate (only UGS)
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0.01
0.5 0.6 1 1.3 1.5 1.7 1.9 2.2
Normalized Offered Load
Dro
p R
ate(
%)
Spec_UGS
Proporsed_UGS
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Delay of real-time service
0
20
40
60
80
100
0.5 0.7 1 1.3 1.5 1.7 1.9 2.2
Normalized Offered Load
Tim
e(m
s)
Proporsed_UGS Proporsed_rtPSSpec_UGS Spec_rtPS
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Delay of non-real-time service
0
500010000
1500020000
2500030000
35000
0.5 0.7 1 1.3 1.5 1.7 1.9 2.2
Normalized Offered Load
Tim
e(m
s)
Proporsed_nrtPSProporsed_BESpec_nrtPSSpec_BE
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Bandwidth util. of Proposed BWA
0
0.2
0.4
0.6
0.8
1
0.5 0.6 1 1.3 1.5 1.8 1.9 2.2
Normalized Offered Load(%)
Thro
ughp
ut(%
)
Proporsed_UGS Proporsed_rtPS Proporsed_nrtPS
Proporsed_BE Total
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Compare of Bandwidth Util.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.5 0.7 1 1.3 1.5 1.7 1.9 2.2
Normalized Offered Load
Thro
ughp
ut(%
)
Proporsed_UGS Proporsed_rtPSSpec_UGS Spec_rtPS
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Fairness of real-time service
0.88
0.9
0.92
0.94
0.96
0.98
1
1.02
1 2 3 4 5 6 7 8 9 10Subscribe Station ID
Thro
ughp
ut(%
)
UGS UGS Average rtPS rtPS Average 0.975
0.98
0.985
0.99
0.995
1
1.005
1 2 3 4 5 6 7 8 9 10
Subscribe Station ID
Thro
ughp
ut(%
)
UGS UGS_AveragertPS rtPS_Average
0.8
0.85
0.9
0.95
1
1.05
1 2 3 4 5 6 7 8 9 10
Subscribe Station ID
Thr
ough
put(%
)
UGS Average_UGS rtPS Average_rtPS
Normalized Offered load(50%) Normalized Offered load(100%)
Normalized Offered load(150%)
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Outline
Background WiMAX Standard Introduction Proposed Algorithm Simulation Conclusion
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Conclustion
Provide Delay and Drop_Rate guarantee for UGS and rtPS
nrtPS has more bandwidth than BE Even in overloading , nrtPS and BE can get
some bandwidth.
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Outline
Background WiMAX Standard Introduction Proposed Algorithm Simulation Conclusion Reference
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reference IEEE 802.16-2004
GuoSong Chu, Deng Wang, and Shunliang Mei, “A QoS Architecture for the MAC Protocol of IEEE 802.16 BWA System,” IEEE 2002 International Conference on Vol. 1, 29 June-1 July 2002 pp. 435-439, 2002.
Dong-Hoon Cho , Jung-Hoon Song, Min-Su Kim, and Kim-Jun Han, “Performance Analysis of the IEEE 802.16 Wireless Metropolitan Area Network,” First International Conference on Distributed Frameworks for Multimedia Applications (DFMA’05), pp. 130-137, 2005.
Kitti Wonghavarawat and Aura Ganz, “Packet Scheduling for QoS support in IEEE 802.16 broadband wireless access system,” International Journal of Communication Systems Vol. 16, Issue 1, pp.81-96.
Kin K. Leung and Arty Srivastava, “Dynamic Allocation of Downlink and Uplink Resource for Broadband Services in Fixed Wireless Networks,” IEEE Journal on Selected Areas in Communications Vol. 17 No. 5, May 1999.
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Q&A
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Virtual Map
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SS1UGS
SS2UGS
SS3UGS
SS4UGS
SS1rtPS
SS2rtPS
SS3rtPS
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