logo bandwidth guaranteed call admission control scheme in ieee 802.16 mobile wimax with qos support...

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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

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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[(

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Motivation(cont.)

8

Outline

IntroductionProposed Bandwidth Guaranteed

CAC SchemeAnalytical ModelNumerical ResultsConclusionFuture WorkReference

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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

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Handoff UGS Connection

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New Call UGS Connection

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Handoff rtPS Connection

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New Call rtPS Connection

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Handoff nrtPS Connection

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New Call nrtPS Connection

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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)

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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)

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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’)

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Analytical Model

}7654321

|,,,,,,{

Cbqbpbmblbkbjbi

qpmlkjisS

State Space

normalized condition

Bandwidth Utilization(%)

Ss

qpmlkji 1),,,,,,(

istateforbqbjbiCiC

CU Ss

ii

,7...21 ,

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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

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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

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Admission Control(UGS)

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Admission Control(rtPS)

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Admission Control(nrtPS)

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Utilization

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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。

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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

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Thanks for your attention!

Q&A

40

Balance Equation

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33

2

1

3

2

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21

qpmlkjiqpmlkji

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qpmlkjiqpmlkjiqqpmlkjiqpmlkjiq

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qpmlkjiqpmlkjimqpmlkjiqpmlkjim

qpmlkjiqpmlkjilqpmlkjiqpmlkjil

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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

,

]7654)1(321[

]76543)1(21[

]765432)1(1[ if,

otherwise

Cbqpbmblbkbjbib

Cqbbpmblbkbjbib

Cqbpbbmlbkbjbib

hn

nnhn

tn

,

]7)1(654321[

]76)1(54321[

]765)1(4321[ if,

42

Comparison(UGS)

43

Comparison(rtPS)

44

Comparison(nrtPS)