A Fair Downlink Packet Scheduling Approach to Support QoS in HSDPA · A Fair Downlink Packet Scheduling Approach to Support QoS in HSDPA Introduction Introduction • In the present

A Fair Downlink Packet Scheduling Approach to Support QoS in HSDPA

A Fair Downlink Packet Scheduling Approachto Support QoS in HSDPA

Deepti Singhal and Naresh Jotwani

The First International Conference on COMmunication Systems and NETworkS(COMSNETS)

January 9, 2009


Contents

1 Introduction

2 Problem Statement3 Other Proposed Scheduling Algorithms

4 Proposed Solution Approach

5 Performance Measure

6 Simulation Environment

7 Simulation ResultsWeb-Traffic ScenarioFTP-Web Traffic ScenarioLoad Analysis

8 Summary & Conclusion

9 References

10 Thank You


Introduction

Introduction

• In the present scenarios, the high-speed demands aregrowing rapidly specially in wireless networks.

• In order to satisfy fast-growing demands in downlink, theconcept of High Speed Downlink Packet Access has beenproposed.

• Packet scheduler in HSDPA controls the allocation ofshared resources to users.


Problem Statement

Problem Statement

• The objective of the paper is to design and evaluate adownlink-scheduling algorithm for HSDPA based UMTSnetworks.

• The resulting algorithm should ensure better channelutilization and fairness among users.


Other Proposed Scheduling Algorithms


• Maximum Carrier to Interference Ratio Scheduling [1]:

j = maxi ri (k) (1)

Where ri (k) is instantaneous C/I ratio

• Proportional Fair Scheduling [1, 2]:According to PF, user j is selected, if

j = maxiri

Ri, i = 1, 2, ..., N. (2)

Ri is the average received rate for user i

• DRC Exponent Rule [3]

j = maxi

rin

Ri, i = 1, 2, ..., N. (3)





j = maxi ri (k) (1)



j = maxiri

Ri, i = 1, 2, ..., N. (2)



j = maxi

rin

Ri, i = 1, 2, ..., N. (3)





j = maxi ri (k) (1)



j = maxiri

Ri, i = 1, 2, ..., N. (2)



j = maxi

rin

Ri, i = 1, 2, ..., N. (3)





j = maxi ri (k) (1)



j = maxiri

Ri, i = 1, 2, ..., N. (2)



j = maxi

rin

Ri, i = 1, 2, ..., N. (3)



Other Proposed Scheduling Algorithms Contd...

• Adaptive Proportional Fair Scheduling [4]:In APF, the user selection criterion is given by

j = maxir cii

Ri∗ RTi , i = 1, 2, ..., N, (4)

ci are updated with

ci = ci + ∆c, if(

RiRTi

− 1N

∑Nj=1

Rj

RTj

)

< −ε

ci = ci − ∆c, if(

RiRTi

− 1N

∑Nj=1

Rj

RTj

)

> ε. (5)



Other Proposed Scheduling Algorithms Contd...

• Adaptive Proportional Fair Scheduling [4]:In APF, the user selection criterion is given by

j = maxir cii

Ri∗ RTi , i = 1, 2, ..., N, (4)

ci are updated with

ci = ci + ∆c, if(

RiRTi

− 1N

∑Nj=1

Rj

RTj

)

< −ε

ci = ci − ∆c, if(

RiRTi

− 1N

∑Nj=1

Rj

RTj

)

> ε. (5)


Proposed Solution Approach

Proposed Solution ApproachFramework for developing Wireless Fair Scheduling Algorithm [5]

Select user i accordingto

Error free Model

Is

leading ??

slot ??relinquish this

should

Select user jaccording to

Compensation Model

Is i = j ??

Update the lead/lagparameterof user i & j

(Lead Lag Model)

Yes

Yes

No

badchannel ??

No

Yes

No

Yes Schedule user i

Schedule user j

Main components of frameworkare:

• Error Free Service Model

• Compensation Model

• Lead and Lag Model

The proposed solution approach isbased on the framework discussedand it replaces Internal working ofModel of this framework.



Wireless Fair - High Speed Scheduling

• Proportion Fair Service Model:This model selects a user with

maxiri

R′

i∗ RTi (6)

• Compensation Model:The maximum limit of lead after which user will relinquishes itsslot is given by

max_li =RTi ∗ TTIduration

mean_channal_ratei(7)

This model is also responsible for selecting user afterrelinquishing. Among the lagging users who perceives goodchannel will be scheduled.



Wireless Fair - High Speed Scheduling

• Proportion Fair Service Model:This model selects a user with

maxiri

R′

i∗ RTi (6)

• Compensation Model:The maximum limit of lead after which user will relinquishes itsslot is given by

max_li =RTi ∗ TTIduration

mean_channal_ratei(7)

This model is also responsible for selecting user afterrelinquishing. Among the lagging users who perceives goodchannel will be scheduled.



Wireless Fair - High Speed Scheduling Contd...

• Lead and Lag Model:if user i gives its slot to user j then lead-lag parameter is updatedwith

li = li − max(

TTIduration,PacketSizei

RTi

)

(8)

lj =

lj +PacketSizej

RTj, if not lagging

min(

0.0, lj +PacketSizej

RTj

)

, if lagging(9)


Performance Measure

Performance Measure

• Link Utilization:

Measured by Mean System Throughput (MAC-hs)• User Level Fairness

Long-term Fairness:Measured by FI by [6]

(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)

Here xi is taken as RiRTi

and N is the number of users

Short-term Fairness:For short-term fairness CDF of waiting time at Node B isused.


Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Performance Measure

Performance Measure




(

∑Ni=1 xi

)2

N∑N

i=1 xi2

, xi ≥ 0, ∀ i (10)





Simulation Environment


• Simulation ToolsNetwork Simulator-2 [7] and Enhanced UMTS Radio AccessNetwork Extensions to NS2 [8]

• Simulation Topology

��

��

��

��

��

��

��

��

��

��

��

��

UE N

UE 2

UE 1

NODE B SGSNRNC GGSN

622 Mb 15 ms

622 Mb 10 ms

node 1

node 2

node N

10 Mb15 ms

622 Mb 0.4 ms

EURANE Support

Figure: Topology used in simulation




• Simulation ParametersParameters ValueCell Radius 600 mNumber of codes used 15Link Adaptation Delay 6 msHARQ Cycle 6 TTINode B Transmission Power 38 dBmNode B Antenna Gain 17 dBShadowing Standard Deviation 3 dBMax. number of HARQ transmission 3Number of parallel HARQ processes 6RLC Acknowledgement Mode AMRLC Buffer Level 500 PDU’sMAC Buffer Level 250 PDU’s


Simulation Results

Simulation ResultsSimulation Scenarios

• Web Traffic ScenarioAverage Load Distribution Scenario - Users are uniformlydistributed in the cell areaWorst Load Distribution Scenario - High requirement usersare in bad channel condition

• FTP-Web Traffic Scenario

• Load Analysis


Simulation Results

Web-Traffic Scenario

Simulation Results - Web-TrafficPedestrian Environments - Users are uniformly distributed in the cell area

0

200

400

600

800

1000

1200

1400

1600

1800

0

0.2

0.4

0.6

0.8

1

1.2

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

(kbp

s)

Fai

rnes

s In

dex

Algorithms

APF ThroughputWS-HSS Throughput

APF FIWF-HSS FI

(a) System Parameters

0

0.1

0.2

0.3

0.4

0.5

ue1 ue2 ue3 ue4 ue5 ue6 ue7 ue8 ue9 ue10ue11ue12ue13ue14ue15ue16ue17ue18

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

/ Req

uire

men

ts o

f use

r

Users

APF RatioWF-HSS Ratio

(b) Users Analysis

Figure: System & Users Analysis


Simulation Results


Simulation Results - Web-TrafficPedestrian Environments - Users are uniformly distributed in the cell area

0.25

0.5

0.75

0.95

0 2 4 6 8 10 12 14 16 18 20

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(a) APF

0.25

0.5

0.75

0.95

2 4 6 8 10 12 14 16 18 20

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(b) WF-HSS

Figure: CDF of MAC-hs delay.


Simulation Results


Simulation Results - Web-TrafficPedestrian Environments - High requirement users are in bad channel condition

0

200

400

600

800

1000

1200

1400

1600

1800

0

0.2

0.4

0.6

0.8

1

1.2

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

(kbp

s)

Fai

rnes

s In

dex

Algorithms


APF FIWF-HSS FI


0

0.1

0.2

0.3

0.4

0.5


Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

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/ Req

uire

men

ts o

f use

r

Users


(b) Users Analysis



Simulation Results


Simulation Results - Web-TrafficPedestrian Environments - High requirement users are in bad channel condition

0.25

0.5

0.75

0.95

0 0.5 1 1.5 2 2.5 3 3.5 4

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(a) APF

0.25

0.5

0.75

0.95

0 0.5 1 1.5 2 2.5 3 3.5 4

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(b) WF-HSS



Simulation Results

FTP-Web Traffic Scenario

Simulation Results - FTP-Web Traffic ScenarioPedestrian Environments

0

500

1000

1500

2000

0

0.2

0.4

0.6

0.8

1

1.2

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

(kbp

s)

Fai

rnes

s In

dex

Algorithms


APF FIWF-HSS FI

Figure: Mean System Throughput (MAC-hs) Achieved and FairnessIndex.


Simulation Results



0

0.1

0.2

0.3

0.4

0.5

ue2 ue4 ue6 ue8 ue10 ue12 ue13 ue15

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

/ Req

uire

men

ts o

f use

r

Users

Web traffic APF RatioWeb traffic WF-HSS Ratio

(a) RiRTi

for Web traffic

0

50

100

150

200

250

ue1 ue3 ue5 ue7 ue9 ue11 ue14

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

Users

FTP APF throughputFTP WF-HSS throughput

(b) MAC-hs Throughput Achievedfor FTP users

Figure: Users analysis


Simulation Results



0.25

0.5

0.75

0.95

0 5 10 15 20 25

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15

(a) APF

0.25

0.5

0.75

0.95

0 5 10 15 20 25

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15

(b) WF-HSS

Figure: CDF of MAC-hs delay


Simulation Results

Load Analysis

Simulation Results - Load AnalysisPedestrian Environment

0

500

1000

1500

2000

3 6 9 12 15 18 21 24 27

Sys

tem

Mea

n T

hrou

ghpu

t Ach

ieve

d (k

bps)

Number of Users

APF MAC-hs ThroughputWF-HSS MAC-hs Throughput

(a) Mean System Throughput(MAC-hs)

0

0.2

0.4

0.6

0.8

1

1.2

3 6 9 12 15 18 21 24 27F

airn

ess

Inde

x (%

)

Number of Users

APFWF-HSS

(b) Fairness Index

Figure: System Parameters by varying load on system

End to End Throughput Vehicular Results


Summary & Conclusion

Summary

• In averagely distributed load, both APF and WF-HSSalgorithm provides good balance between link utilizationand long-term fairness.

• In worst load conditions, WF-HSS provide betterperformance in terms of link utilization in comparison toAPF algorithm.

• CDF of waiting time at Node B shows that WF-HSSalgorithm provides short-term fairness among users for alltraffic scenarios, while APF algorithm fails to do so.



Summary Contd....

• WF-HSS scheduling provides benefits of TCP windowresizing to the FTP users without affecting performance ofother users, while APF algorithm doesn’t do so.

• In comparison to APF algorithm, WF-HSS provides betterlink utilization without affecting fairness among users inheavy load conditions.



Conclusion

WF-HSS algorithm ensures long as well as short time scalefairness among users, according to their QoS requirements,while seeking to maximize link utilization.


Thank You

References:Li-Chun Wang and Ming-Chi Chen.

Comparisons of link-adaptation-based Scheduling algorithms for the WCDMA system with high-speeddownlink packet access.Canadian Journal of Electrical and Computer Engineering (CJECE), Vol. 29:109 – 116, 2004.

R. Pankaj A. Jalali, R. Padovani.

Data Throughput of CDMA-HDR a High Efficiency-High Data Rate Personal Communication WireressSystem.IEEE, VTC, 2000.

J.M. Holtzman.

Asymptotic Analysis of Proportional Fair Algorithm.in Proc. PIMRC, pages 33–37, 2001.

Ghassane Aniba and Sonia Aissa.

Adaptive Proportional Fairness for Packet Scheduling in HSDPA.IEEE Communications Society Globecom, 2004.

Vaduvur Bharghavan Thyagarajan Nandagopal, Songwu Lu.

A Unified Architecture for the Design and Evaluation of Wireless Fair-Queueing Algorithms.Wireless Networks, v.8, 2002.

Rajendra K Jain, Dah-Ming W Chiu, and William R Hawe.

A Quantitative Measure of Fairness and Discrimination for Resource Allocation in Shared Systems.1984.

Network Simulator ns-allinone 2.28 and its documentation is available on http://www.isi.edu/nsnam/dist/.

EURANE patch for clean ns 2.28 and its documentation is available on http://www.ti wmc.nl/eurane/.


Thank You

Thank You


Thank You

Backup Slides


Thank You

Simulation Results - Web-TrafficVehicular Environments - Users are uniformly distributed in the cell area

0

200

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600

800

1000

1200

1400

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1800

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0.2

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(kbp

s)

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APF FIWF-HSS FI


0

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-hs

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(b) Users Analysis



Thank You

Simulation Results - Web-TrafficVehicular Environments - Users are uniformly distributed in the cell area

0.25

0.5

0.75

0.95

0 2 4 6 8 10 12 14 16

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(a) APF

0.25

0.5

0.75

0.95

0 2 4 6 8 10 12 14 16

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(b) WF-HSS



Thank You

Simulation Results - Web-TrafficVehicular Environments - High requirement users are in bad channel condition

0

200

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1200

1400

1600

1800

0

0.2

0.4

0.6

0.8

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-hs

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chie

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(kbp

s)

Fai

rnes

s In

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Algorithms


APF FIWF-HSS FI


0

0.1

0.2

0.3

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0.5


Sys

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Mea

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AC

-hs

Thr

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put A

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/ Req

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men

ts o

f use

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Users


(b) Users Analysis



Thank You

Simulation Results - Web-TrafficVehicular Environments - High requirement users are in bad channel condition

0.25

0.5

0.75

0.95

0 1 2 3 4 5 6 7 8 9 10

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(a) APF

0.25

0.5

0.75

0.95

1 2 3 4 5 6 7 8 9 10

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15u16u17u18

(b) WF-HSS



Thank You

Simulation Results - FTP-Web Traffic ScenarioVehicular Environments

0

200

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800

1000

1200

1400

1600

1800

0

0.2

0.4

0.6

0.8

1

1.2

Sys

tem

Mea

n M

AC

-hs

Thr

ough

put A

chie

ved

(kbp

s)

Fai

rnes

s In

dex

Algorithms


APF FIWF-HSS FI



Thank You


0

0.1

0.2

0.3

0.4

0.5

ue2 ue4 ue6 ue8 ue10 ue12 ue13 ue15

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tem

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-hs

Thr

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put A

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/ Req

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ts o

f use

r

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Web traffic APF RatioWeb traffic WF-HSS Ratio

(a) RiRTi

for Web traffic

0

20

40

60

80

100

120

140

ue1 ue3 ue5 ue7 ue9 ue11 ue14

Sys

tem

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-hs

Thr

ough

put A

chie

ved

Users

FTP APF throughputFTP WF-HSS throughput

(b) MAC-hs Throughput Achievedfor FTP users

Figure: Users analysis


Thank You


0.25

0.5

0.75

0.95

0 2 4 6 8 10 12

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15

(a) APF

0.25

0.5

0.75

0.95

0 2 4 6 8 10 12

CD

F o

f MA

C d

elay

MAC delay (s)

u1u2u3u4u5u6u7u8u9

u10u11u12u13u14u15

(b) WF-HSS

Figure: CDF of MAC-hs delay


Thank You

Simulation Results - Load AnalysisVehicular Environment

0

500

1000

1500

2000

3 6 9 12 15 18 21 24 27

Sys

tem

Mea

n T

hrou

ghpu

t Ach

ieve

d (k

bps)

Number of Users

APF MAC-hs ThroughputWF-HSS MAC-hs Throughput

(a) Mean SystemThroughput(MAC-hs)

0

0.2

0.4

0.6

0.8

1

1.2

3 6 9 12 15 18 21 24 27F

airn

ess

Inde

x (%

)

Number of Users

APFWF-HSS

(b) Fairness Index

Figure: System Parameters by varying load on system

Back to Pedestrian Results


Thank You

Simulation Results - Load AnalysisPedestrian Environments

0

500

1000

1500

2000

3 6 9 12 15 18 21 24 27

Sys

tem

Mea

n T

hrou

ghpu

t Ach

ieve

d (k

bps)

Number of Users

APF MAC-hs ThroughputWF-HSS MAC-hs ThroughputAPF End-to-End Throughput

WF-HSS End-to-End Throughput


Back to Pedestrian Results

Documents

A Fair Downlink Packet Scheduling Approach to Support QoS in HSDPA · A Fair Downlink Packet Scheduling Approach to Support QoS in HSDPA Introduction Introduction • In the present