robust qos control for single carrier pmp mode ieee 802.16 systems authors: xiaofeng bai, abdallah...
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Robust QoS Control for SinRobust QoS Control for Single Carrier PMP Mode IEEgle Carrier PMP Mode IEE
E 802.16 SystemsE 802.16 SystemsAuthors: Xiaofeng Bai, Abdallah ShaAuthors: Xiaofeng Bai, Abdallah Sha
mi, and Yinghua Yemi, and Yinghua Ye
Published: IEEE TMC April 2008Published: IEEE TMC April 2008
OutlineOutline
IntroductionIntroduction System ModelSystem Model Uplink Request Management AgentUplink Request Management Agent Frame Scheduling UnitFrame Scheduling Unit SimulationSimulation ConclusionConclusion
IntroductionIntroduction
Fixed frame lengthFixed frame length Each connection, excepted UGS, requests Each connection, excepted UGS, requests
bandwidth for next frame before the end of bandwidth for next frame before the end of current frame current frame
ProblemsProblems
How many resource do each connection real How many resource do each connection real need?need?
Is the information received by BS up-to-date?Is the information received by BS up-to-date? How to reduce the control overhead?How to reduce the control overhead?
System ModelSystem Model
Frame Scheduling Unit
Uplink Request Management Agent
Do not concern about UGS services
Uplink Request Management AgentUplink Request Management Agent
Symbol definition Symbol definition Bandwidth request
for bandwidth guaranteed and imminent part
Bandwidth request for bandwidth guaranteed and nonim
minent part
Bandwidth request for bandwidth
guaranteed part Bandwidth request for nonbandwidth guaranteed part
Uplink Request Management AgentUplink Request Management Agent
The connection i’s service timer at ti
me t
The connection i’s eligible bandwidth
request
maxiR
QoS Enforcement ModuleQoS Enforcement Module
The connection i’s bandwidth request
The connection i’s QoS timer at time
t
miniR
SS-Request Generation ModuleSS-Request Generation Module
Frame Scheduling UnitFrame Scheduling Unit
Downlink Request ManagementDownlink Request Management Similarly to Uplink Request Management AgentSimilarly to Uplink Request Management Agent
Resource Allocation ModuleResource Allocation Module Frame Creation ModuleFrame Creation Module
Conversion symbol assignment into timing Conversion symbol assignment into timing informationinformation
Resource Allocation ModuleResource Allocation Module
The symbol need of the The symbol need of the PP0 request is 0 request is considered first, then considered first, then PP1 followed by 1 followed by PP2 2 requests.requests.
If the symbol needs of every SG have been If the symbol needs of every SG have been fully accommodated, the remaining symbols fully accommodated, the remaining symbols are assigned to each SG in proportion to the are assigned to each SG in proportion to the number of connections include in the SG.number of connections include in the SG.
Resource Allocation ModuleResource Allocation ModuleThe Pi request in bytes of the jth SG
The number of bits carried by one modulated symbol of
the jth SG
The Pi request in symbols of the jth S
G
The symbols earned by the Pi reques
t of the jth SG
The extra symbols possibly assigned t
o the jth SG
The integer number of symbols finally assigned to the jt
h SG
SimulationSimulation
UCSA: uncontrolled scheduling UCSA: uncontrolled scheduling algorithmalgorithm
Each uplink connection sends individual bandwidth rEach uplink connection sends individual bandwidth requests over the uplink.equests over the uplink.
The symbol needs are estimated only based on the linThe symbol needs are estimated only based on the link capacity information when each connection is estabk capacity information when each connection is established.lished.
The symbol needs of all rtPS connections are accomThe symbol needs of all rtPS connections are accommodated first, then all nrtPS connections, followed by modated first, then all nrtPS connections, followed by all BE connections.all BE connections.
Any nrtPS connection could be serviced only when eAny nrtPS connection could be serviced only when every rtPS connection queue is evacuated and no BE cvery rtPS connection queue is evacuated and no BE connection could be serviced if any rtPS and nrtPS paconnection could be serviced if any rtPS and nrtPS packet is backlogged. ket is backlogged.
uplink rtPS connection of SS5uplink rtPS connection of SS5
uplink nrtPS connection of SS6uplink nrtPS connection of SS6
uplink BE connection of SS5uplink BE connection of SS5
uplink rtPS connection of SS5uplink rtPS connection of SS5
At time 2.0 second, the links from SS8 to the At time 2.0 second, the links from SS8 to the BS degrade from 64-QAM to QPSK.BS degrade from 64-QAM to QPSK.
At time 4.0 second, the links from SS8 to the At time 4.0 second, the links from SS8 to the BS recover from QPSK to 64-QAMBS recover from QPSK to 64-QAM
uplink rtPS connection of SS8uplink rtPS connection of SS8
uplink nrtPS connection of SS8uplink nrtPS connection of SS8
uplink rtPS connection of SS7uplink rtPS connection of SS7
uplink nrtPS connection of SS9uplink nrtPS connection of SS9
uplink BE connection of SS8uplink BE connection of SS8
uplink rtPS connection of SS8uplink rtPS connection of SS8
ConclusionConclusion
The proposed SCSA scheme enable each connThe proposed SCSA scheme enable each connection’s contracted QoS parameters to control ection’s contracted QoS parameters to control the service provided to the connection, which ethe service provided to the connection, which ensures the per-connection QoS guarantee.nsures the per-connection QoS guarantee.
Signaling overhead is reduced.Signaling overhead is reduced. The proposed scheme is robust against wirelesThe proposed scheme is robust against wireles
s link degradation at a particular SS.s link degradation at a particular SS.