adaptive power allocation and call admission control in multi service wimax access networks

8/7/2019 Adaptive Power Allocation and Call Admission Control in Multi Service Wimax Access Networks

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ADAPTIVE POWER ALLOCATION AND

CALL ADMISSION CONTROL INMULTISERVICE WIMAX ACCESS NETWORKS

IEEE Wireless Communications February 2007

Radio Resource Management And Protocol

Engineering For IEEE 802.16

Reporter


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Outline

1. Abstract

2. Introduction

3. Wimax Downlink APA Optimization

4. Deploying CAC In Wimax Access Networks

5. The Cooperation Between APA and CAC

6. Conclusions


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Abstract

From a technical viewpoint, WiMAX is a feasiblealternative to the wired internet accesssolutions such as cable modem and DSL

From the commercial viewpoint, whether thepromise of WiMAX will be materialized stilldepends on its revenue rate to telecomoperators and its service quality to the

subscribers


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Introduction

The choice of broadband Internet access

T1ADSLCABLE

However, these wired infrastructures can be considerablymore expensive and time consuming to deploy than

wireless ones

WiMAX, an IEEE 802.16 standardized wireless technology

10Km

single-channel data rate of up to 75 Mb/s on both the uplink anddownlink.

use multiple WiMAX channels for a single transmission to reach abandwidth of up to 350 Mb/s.


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Introduction

WiMAX technology supports both mesh andpoint-to-multipoint (PMP) networks.

mesh network is usually used forconstructing wide-area wireless backhaulnetwork

PMP network aims at providing the last-mileaccess to a broadband ISP.


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Introduction


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Introduction

Click to edit Master text stylesSecond level

Third level Fourth level Fifth level


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Introduction

Transmission

OFDM (orthogonal frequency division multiplexing)

OFDMA (orthogonal frequency division multiple

access)

Duplex

FDD (Frequency Division Duplex)

TDD (Time Division Duplex)

TDD is more flexible


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Introduction

As one of the most expected features,WiMAX is supposed to have the capability ofaccommodating a variety of traffics,including data transfer, voice, and video.

WiMAX Forum define

Unsolicited Grant Service (UGS)

Real-Time Polling Service (rtPS)

Non-Real-Time Polling Service (nrtPS)

Best Effort (BE)


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Introduction

This article addresses two resourcemanagement mechanisms in WiMAX accessnetworks

Adaptive power allocation (APA)

Call admission control (CAC)


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Wimax Downlink APAOptimization

The WiMAX uplink and downlinktransmission can be optimized by APA,which allows the transmitter to grantdifferent power levels to different

subcarriers according to the channel stateinformation from the physical layer

The service providers usually expect a

power allocation scheme that producesoptimal revenue.


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To investigate the APA revenue of a certainscheme, we define the revenue rate of eachtype of service as the revenue generated bya bandwidth unit. We let rerUGS, rerrtPS,

rernrtPS, and rerBE be the revenue rates ofthe following

Unsolicited Grant Service

Real-Time Polling Service

Non-Real-Time Polling Service

Best-Effort Service


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arriving downlink traffic load in subscriber k's local network

traffic load can generate potential revenue in subscriber k'slocal network

revenue-to-bandwidth ratio of the kth subscriber

The optimal revenue-criterion-based APA allocate morepower resource to the subcarriers that belong to thesubscriber of high revenue-to-bandwidth ratio.


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This consideration leads to fairness-constrainedoptimal revenue criterion

Simulation

OFDMA

32 subscribers

BS-SS distances 2 to 10 km

Power level MQAM

M-ary quadrature amplitude modulation

is 80%

In our simulation, the channel is assumed to have a bad-urban (BU)delay profile [Principles of Mobile Communication]


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Deploying CAC In Wimax AccessNetworks

To handle a multiservice WiMAX accessnetwork, it is very important to employ theCAC mechanism.

CAC is a crucial step for the provision of QoSguaranteed service, because it can preventthe system capacity from being overused.

We suppose a CAC manager is placed in aWiMAX base station.


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1. When an application in subscriber k's localnetwork initiates a connection to the Internet, itsends connection request to the CAC managerwith upstream bandwidth requirement bU anddownstream bandwidth requirement bD.

2. the CAC manager employs uplink CAC policyand downlink CAC policy to make admissiontests on the uplink and downlink separately,and only the connection request passing both

admission tests can be accepted eventually


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Click to edit Master text stylesSecond level

Third level Fourth level Fifth level


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From the perspective of service provider, theadmission control policy that producesoptimal revenue is desired.

From the perspective of WiMAX subscribers,the admission control policy of optimal utilityis expected, since it can produce the

maximum access bandwidth.


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The Cooperation Between APAand CAC


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Conclusion

Since the current standardization activitiesof IEEE 802.16 leave service providers achance to have their own selections in thesetwo technical aspects, distinct designing

criteria that follows can be chosen.

From the perspective of service providers,

optimal revenue is the major concern ofboth APA and CAC design


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Conclusion

From the perspective of subscribers, fairnessis the requirement of APA design, whileoptimal utility is the requirement of CACdesign.

To successfully deploy a commercial WiMAXsystem, we have to take into account the

demands of both service providers andsubscribers.

adaptive power allocation and call admission control in multi service wimax access networks

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