1

LOGO

Bandwidth Guaranteed Call Admission Control Scheme in IEEE 802.16 Mobile WiMAX with QoS Support

Speaker: 黃筱婷指導教授 : 柯開維 教授Date: 2011/05/23

2

Outline

IntroductionProposed Bandwidth Guaranteed

CAC SchemeAnalytical ModelNumerical ResultsConclusionFuture WorkReference

3

Introduction

4

QoS Architecture for IEEE 802.16 MAC Protocol

5

QoS Classes

QoS Category Application QoS Specification

UGSUnsolicited Grant

Service

T1/E1 Transport

•Maximum Sustained Rate•Maximum Latency Tolerate•Jitter Tolerance

rtPSReal-Time Polling

ServiceVoIP

•Minimum Reserved Rate•Maximum Sustained Rate•Maximum Latency Tolerate•Traffic Priority

ErtPSExtended Real-Time

Polling ServiceMPEG Video

•Minimum Reserved Rate•Maximum Sustained Rate•Maximum Latency Tolerate•Jitter Tolerance•Traffic Priority

nrtPSNon-Real-Time Polling

ServiceFTP

•Minimum Reserved Rate•Maximum Sustained Rate•Traffic Priority

BEBest-Effort Service HTTP •Maximum Sustained Rate

•Traffic Priority

priority

高

低

6

Motivation[2] 提了一個 Bandwidth and Delay

Guaranteed CAC scheme ，利用 [3] 提出的公式

　 ，計算出 rtPS 的 delay 後再依據所需頻寬大小判斷是否需降階，決定是否能接收此連線。

優點：此方法有考慮到 delay 與 handoff 的狀況缺點：一次將整個 class 的所有連線都降一階，會

讓系統的 utilization 下降，容易造成浪費的情況。所以我們提出了要一個一個降的並加入 recovery

的方法，希望能大幅增加 utilization 。

frCCmb irtPSNRTii )]1/1)(1[(

7

Motivation(cont.)

8

Outline

IntroductionProposed Bandwidth Guaranteed

CAC SchemeAnalytical ModelNumerical ResultsConclusionFuture WorkReference

9

Proposed CAC SchemeH:Handoff, N:New callPriority: H-UGS>H-rtPS>N-UGS>N-rtPS >H-nrtPS>N-nrtPS

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Degradation1

(UGS,rtPS1,rtPS2,rtPS3,nrtPS1,

nrtPS2,nrtPS3)使用於有 New Call

UGS/rtPS 與Handoff nrtPS 連線想要進來的時候

可以讓 nrtPS 的連線降階，盡量讓提出要求的連線都能進來

11

Degradation2

(UGS,rtPS1, rtPS2,rtPS3,nrtPS1, nrtPS2,nrtPS3)使用於有 Handoff

UGS 與 Handoff rtPS連線想要進來的時候

可以讓 nrtPS 與 rtPS的連線降階，盡量讓提出要求的連線都能進來

12

Recovery

(UGS,rtPS1, rtPS2,rtPS3, nrtPS1,nrtPS2, nrtPS3)使用於有連線要離

開的時候盡量把頻寬用完使

得 Utilization 能夠提高

13

Handoff UGS Connection

14

New Call UGS Connection

15

Handoff rtPS Connection

16

New Call rtPS Connection

17

Handoff nrtPS Connection

18

New Call nrtPS Connection

19

Outline

IntroductionProposed Bandwidth Guaranteed

CAC SchemeAnalytical ModelNumerical ResultsConclusionFuture WorkReference

20

Analytical Model

Continuous Time Markov Chain Model (i, j, k, l, m, p, q) = (UGS, rtPS1, rtPS2, rtPS3, nrtPS1,

nrtPS2, nrtPS3) 的連線數 (b1, b2, b3, b4, b5, b6, b7) = (UGS, rtPS1, rtPS2,

rtPS3, nrtPS1, nrtPS2, nrtPS3) 之可使用的頻寬大小 Δr = b2 - b3 = b3 – b4 Δn = b5 – b6 = b6 – b7 (b1, b2, b3, b4, b5, b6, b7) 又可表示成 (b1, 3Δr, 2Δr, Δr, 3Δn, 2Δn, Δn) C = 在 BS 中可讓連線使用的頻寬總量 (Mbps)

21

Analytical Model(cont.)

Arrival process of the handoff and new call UGS, rtPS, and nrtPS connections is Poisson with λhu, λhr, λhn, λnu, λnr, λnn, and λT = λhu+λhr+λhn+λnu+λnr+λnn

The service time of UGS, rtPS and nrtPS connection are exponentially distributed with mean 1/μu, 1/μr1, 1/μr2, 1/μr3, 1/μn1, 1/μn2, 1/μn3

steady state prob. of the state s=(i, j, k, l, m, p, q) is represented by π(i, j, k, l, m, p, q)

22

State Transition Rate of the Markov Chain

Current State Transition Rate Next State

(i,j,k,l,m,p,q)

λhu (i+1,j’,k’,l’,m’,p’,q’)

λnu (i+1,j,k,l,m’,p’,q’)

λhr (i,j’+1,k’,l’,m’,p’,q’)

λnr (i,j+1,k,l,m’,p’,q’)

λhr (i,j’,k’+1,l’,m’,p’,q’)

λnr (i,j,k+1,l,m’,p’,q’)

λhr (i,j’,k’,l’+1,m’,p’,q’)

λnr (i,j,k,l+1,m’,p’,q’)

λhn (i,j,k,l,m’+1,p’,q’)

λnn (i,j,k,l,m+1,p,q)

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State Transition Rate of the Markov Chain(cont.)

Current State Transition Rate Next State

(i,j,k,l,m,p,q)

λhn (i,j,k,l,m’,p’+1,q’)

λnn (i,j,k,l,m,p+1,q)

λhn (i,j,k,l,m’,p’,q’+1)

λnn (i,j,k,l,m,p,q+1)

i ． μu (i-1,j’,k’,l’,m’,p’,q’)

j ． μr1 (i,j’,k’,l’,m’,p’,q’)

k ． μr2 (i,j’,k’,l’,m’,p’,q’)

l ． μr3 (i,j’,k’,l’,m’,p’,q’)

m ． μn1 (i,j’,k’,l’,m’,p’,q’)

p ． μn2 (i,j’,k’,l’,m’,p’,q’)

q ． μn3 (i,j’,k’,l’,m’,p’,q’)

24

Analytical Model

}7654321

|,,,,,,{

Cbqbpbmblbkbjbi

qpmlkjisS

State Space

normalized condition

Bandwidth Utilization(%)

Ss

qpmlkji 1),,,,,,(

istateforbqbjbiCiC

CU Ss

ii

,7...21 ,

25

Handoff Connection Dropping Probability

the Prob. of rejecting a handoff connection request for admission into the network.

)}1()2()2(|),,,,,,({

, _'

),,,,,,(

Rbpmkjqpmlkjis

SwhereDP

nr

UGSDPSs

qpmlkjiUGS

)}4()2()2(|),,,,,,({

, _'

),,,,,,(

Rbpmkjqpmlkjis

SwhereDP

nr

rtPSDPSs

qpmlkjirtPS

)}7()2(|),,,,,,({ _

'),,,,,,(

RbpmqpmlkjisSwhere

DP

nnrtPSDP

SsqpmlkjinrtPS

26

New Connection Blocking Probability

The Prob. of rejecting a new connection request for admission into the network.

)}1()2(|),,,,,,({ _

'),,,,,,(

RbpmqpmlkjisSwhere

BP

nUGSBP

SsqpmlkjiUGS

)}4()2(|),,,,,,({ _

'),,,,,,(

RbpmqpmlkjisSwhere

BP

nrtPSBP

SsqpmlkjirtPS

)}7()6()5(|),,,,,,({

, _'

),,,,,,(

bRbRbRqpmlkjis

SwhereBP nrtPSBPSs

qpmlkjinrtPS

27

Outline

IntroductionProposed Bandwidth Guaranteed

CAC SchemeAnalytical ModelNumerical ResultsConclusionFuture WorkReference

28

System Parametertotal uplink capacity available at BS is

4096Kbps.QoS Parameter(UGS,rtPS1,rtPS2,rtPS3,nrtPS1,nrtPS2,nrtPS3)=(256,1023,682,341,1023,682,341)λhu = λnu = λhr= λnr= λhn= λnn

μu=μr1=μr2=μr3= μn1=μn2=μn3=0.2system load(ρ)

C

bii i

i

N

29

Admission Control(UGS)

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Admission Control(rtPS)

31

Admission Control(nrtPS)

32

Utilization

33

保留部分頻寬 recovery 時每次只升回部分頻寬，不要每次都把頻寬盡量用

完，這樣可以用來微調剩餘的保留頻寬大小，在 Utilization與 Blocking 間微調取得最適合現在網路環境的方法

34

Outline

IntroductionProposed Bandwidth Guaranteed

CAC SchemeAnalytical ModelNumerical ResultsConclusionFuture WorkReference

35

Conclusion

舉例：如右圖所示。(5,1,2,1,0,0,0) 為一個blocking state ，在只有降的時候 steady-state prob. = 0.0001973118 ，升 + 降時是 0.001406381 ，因此可得知在加入升的演算法的時候，跳到 blocking state 的機率增加，進而造成 blocking prob. 增加。

加入 recovery 的時候，由於 blocking state 的steady state prob. 變大，所以造成 blocking prob. 也跟著增加。

36

Conclusion(cont.)

只有做 degradation 的時候， blocking prob. 有明顯的改進。

除了 degradation 之外再加上 recovery之後， utilization 大幅增加。

利用調整頻寬保留的比例來決定 blocking prob. 和 utilization 的大小，以適用於不同的網路環境。

37

Future Work

找出合理的 C 與合適的 R 提升系統效能分析當 handoff 和 new call

connection 所佔比例不同時的結果。推導 rtPS 與 nrtPS 有 n 個 class 的

general form 。

38

Reference

[1] IEEE Std 802.16-2009, “IEEE Standard for Local and Metropolitan Area Networks Part 16: Air Interface for Broadband Wireless Access Systems,”May, 2009.

[2] K. Etemad, “Overview of Mobile WiMAX Technology and Evolution”, IEEE Communications Magazine, vol. 46(10), pp. 31-40, October 2008

[3]  S. Kalikivayi, I.S. Misra, and K. Saha, “Bandwidth and Delay Guaranteed Call Admission Control Scheme for QOS Provisioning in IEEE 802.16e Mobile WiMAX,” IEEE conference on Global telecommunications, pp. 1-6, 2008.

[4] Kitti Wongthavarawat, and Aura Ganz, “Packet scheduling for QoS support in IEEE 802.16 broadband wireless access systems,” International Journal of Communication Systems, vol. 16, issue 1 , pp. 81-96, February 2003

39

Thanks for your attention!

Q&A

40

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33

2

1

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21

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tn

trtu

nn

n

n

r

r

r

u

nnnr

rru

nn

hn

nr

hr

nuhu

41

Balance Equation(cont.)

δ(i,j,k,l,m,p,q)

λtu

λtr

λtn

otherwise

Sqpmlkjiqpmlkji ,0

),,,,,,(,1),,,,,,(

otherwise

Cqbpbmblbkbjbbiif

hu

nuhutu ,

7654321)1(,

otherwise

Cqbpbmbblkbjbib

Cqbpbmblbbkjbib

Cqbpbmblbkbbjib

hr

nrhr

tr

,

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]76543)1(21[

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otherwise

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Cqbpbbmlbkbjbib

hn

nnhn

tn

,

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]76)1(54321[

]765)1(4321[ if,

42

Comparison(UGS)

43

Comparison(rtPS)

44

Comparison(nrtPS)