A Study of the Bandwidth Management Architecture over IEEE 802.16 WiMAX

Student : Sih-Han ChenAdvisor : Ho-Ting WuDate : 2008.5.6

Outline

• Introduction of IEEE802.16 QoS• Proposed QoS System Architecture

– Pairing Call Admission Control– Bandwidth Borrowing on CAC level– Two Stage Bandwidth Allocation

• Simulation Result• Conclusion and Future Work

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Wireless TechnologiesBandwidth

1 Gbps

100 Mbps

10 Mbps

1 Mbps

PAN LAN MAN WAN<1m 10m 100m Up to 50Km Up to 80Km

802.15.1Bluetooth

Wi-Fi802.11a/g

Wi-Fi802.11b

802.15.3High Speed

WirelessPAN

Wi-MAX802.16

(802.16-2004 & 802.16e)

4G

3G

2.5G

IEEE 802.15 IEEE 802.11 IEEE 802.16 3GPP

PAN: Personal area networksMAN: Metropolitan area networks

LAN: Local area networks Wide area networks

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IEEE 802.16 Operation ModePoint to MultiPoint (PMP) Mode Mesh Mode (Optional)

(a) (b)

Mesh SS

Mesh SS WiMAXBackhaulnetwork

SS

SS

SS

SSBS

Mesh SS

Base Station (BS)

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MAC Common Part Sublayer

• Defines multiple-access mechanism

• Functions ：– connection establishment– connection maintenance– Call admission control – bandwidth request– bandwidth allocation

MAC Common Part Sublayer

(MPC)

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IEEE 802.16 TDD frame structureFrame n-1 Frame n Frame n+1

DL Subframe UL Subframe

Preamble FCH DL-Burst #1

DL-Burst #2-4

DL-Burst #5

DL-Burst #6

TTG

RTG

Initialranging

BWrequest

UL-Burst #1

UL-Burst #2

DLFP DL-MAP UL-MAP MAC messages, Mac PDUs

IEIE IE IE IE IE IE IE IE IE

Preamble FCH DL-Bursts#1-4 DL-Burst #5 DL-Burst #6 Initialranging

BWrequest

UL-Burst #1

UL-Burst #2

Preamble(optional)

MACPDU

MACPDU

Pad PreambleMACPDU

MACPDU

Midamble(optional)

MACPDU

MACPDU

Pad

每個UL-Burst內的資料，都必須來自同一台SS每個DL-Burst內的資料，有可能是要送給不同SS

IE IE

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DL-MAP and UL-MAP

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Downlink Subframe

Broadcast

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Uplink Subframe

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Media Acces Control (MAC)

• Connection orienteded– Service Flow(SF)– Connection ID (CID)

• Channel access:– UL-MAP

• Defines uplink channel access• Defines uplink data burst profiles

– DL-MAP• Defines downlink data burst profiles

– UL-MAP and DL-MAP are both transmitted in the beginning of each downlink subframe (FDD and TDD).

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Bandwidth Request

• SSs may request bandwidth in 3 ways:– Use the ”contention request opportunities”

interval upon being polled by the BS (unicast, multicast or broadcast poll)

– Send a standalone MAC message called ”BW request” in an already granted slot

– Piggyback a BW request message on a data packet

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Bandwidth Allocation• BS grants/allocates bandwidth in one of two

modes– Grant Per Subscriber Station (GPSS)– Grant Per Connection (GPC)

• Decision based on requested BW, QoS parameters and available resources

• Grants are realized through the UL-MAP

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Service Classes

• Unsolicited Grant Services (UGS): – Constant Bit Rate (CBR) services, – T1/E1 emulation, and Voice Over IP (VoIP)

• Real-Time Polling Services (rtPS): – real-time services variable size data packets– MPEG video or VoIP with silence suppression.

• Non-Real-Time Polling Services (nrtPS): – Used for delay tolerant traffic requiring some minimum data rate– FTP

• Best Effort Services (BE) :– Used for streams with no rate guarantees.– WEB , HTTP

IEEE 802.16 QoS Provisioning

• Service Flow QoS Scheduling• Dynamic Service Establishment• Two-phase Activation

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Service Flow• The central concept of the MAC protocol• A service flow is a unidirectional flow of

packets that is provided a particular QoS.• SS and BS provide this QoS according to the

QoS parameter set.• Existing in both uplink and downlink and may

exist without being activated.• Must have a 32bit SFID, besides admitted and

active status also have a 16-bit CID

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Attributes of a Service Flow

• Service Flow ID• CID• Provisioned Qos Parameter Set• Admitted QoS Parameter Set• Active QoS Parameter Set• Authorization Module

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Relationship of QoS Parameter Set

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Authorized QoS Parameter Set = Provisioned QoS Parameter Set(SFID)

Admitted QoS Parameter Set(SFID & CID)

Active QoS Parameter Set(SFID & CID)

Type of Service Flow• Provisioned Service Flows

– Provided by external network management system– Admitted and Active QoSParamSet are NULL

• Admitted Service Flows– Reserved resource according AdmittedQoSParamSet,

but not yet activated– First Stage of two-phase activation model

• Active Service Flows– Active QoS Parameter Set is non-NULL – Second Stage of two-phase activation model

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Dynamic Service Management• Dynamic Service Activate (DSA)

– Activate a service flow

• Dynamic Service Change (DSC)– Change an existing service flow

• Dynamic Service Delete (DSD)– Delete a service flow

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Dynamic Service Establishment

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DSA message flow SS-initiated DSA message flow BS-initiated

(a) (b)

SS

DSX-RVD

DSA-REQ

(Without SFID and CID)

BS

DSA-RSP

DSA-ACK

SS

DSA-REQ

BS

DSA-ACK

DSA-RSP

(SFID and Transport CID)

(SFID and Transport CID)

Outline

• Introduction of IEEE802.16 QoS• Proposed QoS System Architecture

– Pairing Call Admission Control– Bandwidth Borrowing on CAC level– Two Stage Bandwidth Allocation

• Simulation Result• Conclusion and Future Work

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Proposeed QoS Architecture

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Two Stage Bandwidth Allocation

Downlink Packet Scheduler

Cor

e N

etw

ork

ApplicationsPair Call Admission Control

BandwidthBorrowingAgent

Uplink Packet Scheduler

Downlink Data Traffic

Connection Request

Connection Response

UGS

rtPS

nrtPS

BE

UplinkData Traffic

Two Stage Bandwidth Allocation

UGS

rtPS

nrtPS

BE

Down Stream(DL/UL MAP)

Up Stream

BS SS

Outline

• Introduction of IEEE802.16 QoS• Proposed QoS System Architecture

– Pairing Call Admission Control– Bandwidth Borrowing on CAC level– Two Stage Bandwidth Allocation

• Simulation Result• Conclusion and Future Work

4/29/2008Page 23

Abbreviations Definition

Total System Bandwidth Resource

Remaining Available System Bandwidth Resource

Connection Request

Peak Traffic Rate of DL Connection Request

Average Traffic Rate of DL/UL Connection Request

Min Traffic Rate of DL/UL Connection Request

Reserved Bw for DL/UL Connection after CAC

totalRavailableR

/DL UL

PeakRateCr/DL UL

AvgRateCr/DL UL

MinRateCr/DL UL

BwRsv

Cr

Pairing Call Admission Control

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Connection Response

Is UGS? Is rtPS?

Pairing Call Admission Control

Is rtPS? Is rtPS?

Connection Request

/ /DL UL DL UL

Bw PeakRateRsv Cr

/ /

/

2

DL UL DL UL

DL UL PeakRate AvgRate

Bw

Cr CrRsv

/ /

/

2

DL UL DL UL

DL UL AvgRate MinRate

Bw

Cr CrRsv

//

2

DL ULDL UL MinRateBw

CrRsv

Is UGS?

Pair Connection Request

/ /DL UL DL UL

Bw PeakRateRsv Cr

/ /

/

2

DL UL DL UL

DL UL PeakRate AvgRate

Bw

Cr CrRsv

/ /

/

2

DL UL DL UL

DL UL AvgRate MinRate

Bw

Cr CrRsv

//

2

DL ULDL UL MinRateBw

CrRsv

Is rtPS?

Is nrtPS?

Is BE?

DL UL

BwRsv

Ravailable >=

Y

Y

Y

Y

N

N

NEnable BandwidthBorrowing ?

Y

Accept Pair Call

N

Reject Call

N

Y

Go Bandwidth Borrowing Agent

Pairing Call Admission Control

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