UNIVERSITI PUTRA MALAYSIA

QUALITY OF SERVICE-BASED MEDIUM ACCESS CONTROL MECHANISM FOR MULTIMEDIA TRAFFIC IN MOBILE AD HOC

NETWORKS

MUBARAK ABDALLAH JAMA

FK 2009 90

QUALITY OF SERVICE-BASED MEDIUM ACCESS CONTROL MECHANISM FOR MULTIMEDIA TRAFFIC IN MOBILE AD HOC

NETWORKS

MUBARAK ABDALLAH JAMA

MASTER OF SCIENCE UNIVERSITI PUTRA MALAYSIA

2009

QUALITY OF SERVICE-BASED MEDIUM ACCESS CONTROL MECHANISM FOR MULTIMEDIA TRAFFIC IN MOBILE AD HOC

NETWORKS

By

MUBARAK ABDALLAH JAMA

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirements for the Degree of Master of Science

June 2009

Dedicated to

My loving parents,

my sisters and my brother

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science

QUALITY OF SERVICE-BASED MEDIUM ACCESS CONTROL

MECHANISM FOR MULITIMEDIA TRAFFIC IN MOBILE AD HOC NETWORKS

By

MUBARAK ABDALLAH JAMA

June 2009

Chairman: Borhanuddin Bin Mohd Ali, PhD Faculty: Engineering

This thesis describes an investigation on the problem of quality of service (QoS)

support in mobile ad hoc networks (MANETs). The decentralized nature of wireless

ad hoc networks makes them suitable for a variety of applications where central

nodes cannot be relied on. This thesis presents a medium access control (MAC) QoS

mechanism for multimedia applications in IEEE 802.11e based MANETs. IEEE

802.11e standard draft includes new features to facilitate and promote the provision

of QoS guarantees in wireless networks with a long-term solution based on QoS-

architectures. The motivation is driven by the need to support increasing demand of

time-sensitive applications such as Voice over IP (VoIP) and video conferencing

applications.

IEEE 802.11e enhances the Distributed Coordination Function (DCF) and the Point

Coordination Function (PCF) of the legacy IEEE 802.11, through a new coordination

function: the Hybrid Coordination Function (HCF). Within the HCF, there are two

methods of channel access: HCF Controlled Channel Access (HCCA) and Enhanced

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Distributed Channel Access (EDCA). EDCA operates in infrastructure-less ad hoc

mode and is widely used in MANETs, unlike HCCA, which further assures QoS

provisioning operates in infrastructure mode in the presence of access points (AP).

Recent researches showed that EDCA lacks QoS support of real-time traffic in

MANETs due to its contention based medium access method.

This thesis takes HCCA QoS provisioning potentials to MANETs by implementing a

MAC mechanism in which HCCA is employed on top of EDCA to work in

infrastructure-less environment like MANET with the help of multiple channels. The

mechanism dedicates a unique receiver-based channel to every mobile node. It will

act as virtual hybrid coordinator (VHC) to exercise control over the channel in

contention-free manner while maintaining a common channel in which all mobile

nodes can exchange broadcast and routing related messages.

The mechanism can be easily integrated with existing 802.11 systems without

modification to existing protocols while ensuring a level of admission control and

resource reservation over the medium. Simulation results indicate that the

mechanism significantly improves the overall network throughput by 20% at the

saturation point and improves average delay by 20% at the saturation point compared

to pure EDCA with or without multiple channels. Even with multi-channel EDCA,

our mechanism guarantees better performance in terms of throughput and MAC

delay for high priority traffic in MANET. The research contribution on MAC layer

can be integrated into a larger framework for QoS support in MANETs, which opens

a wide range of further research in QoS provisioning in MANETs and solve QoS

multi-layer design and implementation issues.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains

KUALITI PERKHIDMATAN MEKANISMA MAC DALAM TRAFIK MULTIMEDIA DALAM JARINGAN AD HOC MUDAH ALIH

Oleh

MUBARAK ABDALLAH JAMA

Jun 2009

Pengerusi : Borhanuddin Bin Mohd Ali, PhD

Fakulti : Kejuruteraan

Tesis ini mengkaji masalah kualiti perkhidmatan (QoS) dalam jaringan ad hoc mudah

alih (MANETs) iaitu sejenis reka bentuk jaringan yang dicirikan oleh topologi

dinamiknya dan kekurangan sumbernya. Ia membekalkan suatu mekanisma QoS

kawalan capaian media (MAC) untuk aplikasi multimedia di dalam MANET

berdasarkan IEEE 802.11e. Pelan piawai IEEE 802.11e mempunyai ciri-ciri baru

untuk memudahkan dan mendorong pelaksanaan jaminan QoS di dalam jaringan

tanpa wayar dengan penyelesaian jangka masa panjang berasaskan reka bentuk QoS.

Motivasi ini berdasarkandidorong oleh keperluan untuk menyokong permintaan

untuk aplikasi yang sensitif terhadap masa seperti Voice over IP (VoIP) dan aplikasi

persidangan video.

IEEE 802.11e meningatkan prestasi Fungsi Koordinasi Tertabur (DCF) dan Fungsi

Koordinasi Titik (PCF) daripada IEEE 802.11 melalui fungsi koordinasi yang baru

iaitu: Fungsi Koordinasi Hibrid (HCF) dalam HKF, dan terdapat juga dua kaedah

akses saluran iaitu: Akses Saluran Terkawal HKF (HCCA) dan Akses Saluran

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Tertabur Tertingkat (EDCA). EDCA beroperasi dalam mod ad hoc dan tiada

infrastruktur yang digunakan secara meluas di dalam MANET: perkara ini berbeza

dengan ASTH, kerana ASTH memastikan sokongan QoS beroperasi dalam mod

berinfrastruktur dengan adanya titik akses. Penyelidikan kini menunjukkan bahawa

EDCA tiada sokongan QoS untuk trafik semasa di dalam MANETs dan ini

disebabkan oleh masalah dalam kaedah akses medianya yang berkonflik.

Penyelidikan ini mengambil HCCA QoS sebagai sokongan dan usaha kepada

MANET dengan mengaplikasikan satu mekanisma MAC di mana HCCA digunakan

bersama dengan EDCA dalam keadaan tiada infrastruktur dengan bantuan multi-

saluran. Mekanisma ini menyediakan satu saluran unik yang bergantung kepada

penerima bagi setiap nodus mudah alih. Ia akan bertindak sebagai pengkoordinasi

hibrid virtual untuk mengawal saluran dalam cara yang tidak berkonflik, dan pada

masa yang sama mengekalkan satu saluran umum, di mana semua nodus mudah alih

mampu menukar ganti mesej penyiaran atau yang berkaitan dengan routing.

Mekanisma ini boleh diintegrasikan dalam sistem 802.11 yang sedia ada dengan

mudah, tanpa mengubahsuaikan protokol yang sedia ada. Pada masa yang sama, ia

memastikan terdapatnya kawalan terhadap kemasukan dan sumber tempahan di

dalam saluran. Hasil simulasi menunjukkan bahawa mekanisma ini memperbaiki lagi

keseluruhan jaringan dan kelewatan menghantar data, berbanding dengan EDCA,

tidak kira dengan adanya atau tiadanya multi-saluran.

Penyumbangan kajian ini ke atas lapisan MAC boleh diintegrasikan dalam rangka

yang lebih besar untuk sokongan QoS di dalam MANETs. Ini meluaskan lagi

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peluang untuk kajian yang lain lebih lanjut dengan sokongan QoS di dalam

MANETs, dan menyelesaikan isu-isu reka bentuk QoS yang multi-lapisan serta

penggunaannya.

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ACKNOWLEDGEMENTS

In the name of Allah, the most Merciful, Gracious and most Compassionate, Creator

of all knowledge for eternity. We beg for peace and blessing upon our Master the

beloved Prophet Mohammed (Peace and Blessing be Upon Him) and his progeny,

companions and followers.

I wish to extend my deepest appreciation and gratitude to Islamic Development Bank

(IDB) for sponsoring me to pursue my higher studies by granting me M.Sc.

scholarship. Without IDB Scholarship I wouldn’t be able to achieve my dream,

thanks a lot.

I wish to extend my deepest appreciation and gratitude to the supervisory committee

led by Prof. Dr. Borhanuddin b. Mohd Ali and committee member Dr. Mohd. Fadlee

b. A. Rasid for the various guidance, sharing of intellectual experiences and in giving

me the vital help to conquer the numerous challenges of this study and for their help

and understanding during my hard times.

Also special thanks to my parents and my family for their prayers and providing me

with the strength. May thanks are also extended to my friends Wasim, Yahya, Wafi,

Osama, Dr. Abdallah, Nedhal, Wael, Aus and Dr. Fadhel for their great help to after

my accident and the lab colleagues for sharing experiences throughout my studies.

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I certify that an Examination Committee has met on 23 June 2009 to conduct the final examination of Mubarak Abdallah Jama on his thesis entitles “QUALITY OF SERVICE MACHANISM FOR MULITIMEDIA TRAFFIC IN MOBILE ADHOC NETWORKS (MANETs)” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulation 1981. The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows: Sabira Khatun, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) replace this Nor Kamariah Noordin, PhD Associate Professor Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Raja Syamsul Azmir Raja Abdullah, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Internal Examiner) Varun Jeoti, PhD Associate Professor Faculty of Engineering Universiti Teknologi Petronas (External Examiner)

___________________________________ BUJANG KIM HUAT, PhD Professor / Deputy Dean School of Graduate Studies Universiti Putra Malaysia Date:

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This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. The members of the Supervisory Committee were as follows: Borhanuddin Mohd Ali, PhD Professor Faculty of Engineering Universiti Putra Malaysia (Chairman) Mohd. Fadlee A. Rasid, PhD Lecturer Faculty of Engineering Universiti Putra Malaysia (Member)

HASANAH MOHD GHAZALI, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia

Date: 11 February 2010

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DECLARATION

I hereby declare that the thesis is based on my original work except for quotation and citation which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any degree at UPM or other institution.

_____________________________ MUBARAK ABDALLAH JAMA

Date: 10th December 2009

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TABLE OF CONTENTS

Page

DEDICATION ii ABSTRACT iii ABSTRAK v ACKNOWLEDGEMENTS vii APPROVAL viii DECLARATION x LIST OF TABLES xiv LIST OF FIGURES xv LIST OF ABBREVIATIONS xvii CHAPTER

1 INTRODUCTION 1.1 Background 19 1.2 Scope 21 1.3 Motivation 23 1.4 Aim and objectives 25 1.5 Contributions 26 1.6 Thesis outline 26

2 LITERATURE REVIEW 2.1 Introduction 28 2.2 Mobile Ad hoc Network (MANET) 29 2.3 Quality of Service 32 2.4 Classification of Wireless MAC Protocols 35 2.5 Medium Access Control for Mobile Ad hoc Networks 39 2.5.1 Schemes that use Simple Random Access Only 39 2.5.2 Schemes Facilitating Fairness 50 2.5.3

Protocols Enabling MAC-Level Service Differentiation 51

2.6 IEEE 802.11e 58 2.7 Next generation networks 62 2.8 Summary 63

3 METHODOLOGY 3.1 Introduction 65 3.2 Research Assumptions 65 3.3 The QoS-Aware MAC Mechanism 66 3.5 Need for the Creation Multiple Parallel Channels 67 3.6 Mechanism Description 70 3.7 MAC-Level Admission Control 81 3.8 Channel Assignment 83 3.9 NS-2 Multi-channel module 84 3.10 Summary 88

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4 RESULT AND DISCUSSION 4.1 Introduction 89 4.2 Network Simulator 89 4.3 Simulation Model Setup 90 4.4 Results 95 4.4.1 Throughput 100 4.4.2 MAC-Delay 104 4.4.3

4.4.4 Effect of node speed in throughput Effect of node increase in MAC delay

106 108

5 CONCLUSION AND FUTURE DIRECTION 110 5.1 Overview 111 REFERENCES 113 APPENDICES 115 BIODATA OF STUDENT 133

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LIST OF TABLES

Table Page

2.1 ITU-T Study Group 12 – Performance Targets for Key Multimedia Applications.

40

2.2 Traffic Categories in EDCF 68

4.2 Physical and MAC layer parameters used in simulation

89

4.3 Traffic parameters used in simulation 92

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LIST OF FIGURES

Figure Page

2.1 MANET Typical Topology. 27

2.2 Effects of Location-Dependent Sensing. 43

2.3 Classification of Wireless MAC Protocols. 46

2.4 Growth in random backoff range with number of retries. 54

2.5 Distributed MAC-level Service Differentiation. 62

3.1 The Research Chart. 76

3.2 The operational model of QoS MAC mechanism. 82

3.3 An example to demonstrate the working of the MAC mechanism. 83

3.4 Flowchart for the operations performed by any sender A. 85

3.5 Flowchart for the Operations Performed by any Next-hop Node B. 87

3.6 Frame transfers during the HCCA period of a Superframe. 89

3.7 Single channel module of default NS-2 node

86

3.8 Modified NS-2 node with multi-channel support 87

4.1 Simplified User's View of NS. 90

4.2 Screenshot of the simulation scenario. 92

4.3 The association procedure as observed in trace file. 96

4.4 The HCCA super-frame transmission procedure. 98

4.5 Throughput as a function of Offered Load. 101

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4.6 Multi-channel throughput as a function of Offered Load. 102

4.7 Voice throughput as a function of Offered Load. 103

4.8 Video throughput as a function of Offered Load. 104

4.9 Delay as a function of Number of Sessions 105

4.10 Multi-channel MAC Delay as a function of Number of Sessions. 106

4.11 Throughput as function of Offered load (node speed 20 m/s) 107

4.12 Throughput as function of Offered load (node speed 30 m/s) 108

4.13 MAC-delay as function of number of sessions (100 nodes) 109

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LIST OF ABBREVIATIONS

ACK Acknowledgement

AP Access Point

AReq Association Request

ARes Association Response

CBR Constant Bit Rate

CFP Contention Free Period

CP Contention Period

CSMA Carrier Sense Multiple Access

CSMA-CD Carrier Sense Multiple Access with Collision Detection

CW Contention Window

DCF Distributed Coordination Function

DiffServ Differentiated Services

DIFS Distributed Coordination Function IFS

EDCA Enhanced Distributed Channel Access

FTP File Transfer Protocol

HCCA HCF Controlled Channel Access

HCF Hybrid Coordination Function

IFS Inter-Frame Space

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IntServ Integrated Services

ITU - T International Telecommunication Union – Telecommunication

MAC Medium Access Control

MANET Mobile Ad hoc NETworks

MN Mobile Node

PCF Point Coordination Function

QoS Quality of Service

RIFS Reservation IFS

VHC Virtual Hybrid Coordinator

VoIP Voice over IP

WLAN Wireless Local Area Network

CHAPTER 1

INTRODUCTION

1.1 Background

The ability to communicate with anyone from anywhere on the planet has been

mankind’s dream for a long time. Wireless networks are the only key to enable such

unwired communication. However, with the recent technological advances, coupled

with the demand for flexibility and mobility of wireless systems, the development of

"anywhere and anytime" concept of mobile ad hoc networking becomes a reality.

Mobile ad hoc networks (MANETs) have the potential to serve as the basic building

blocks of the future ubiquitous communication and computing systems, capable of

interconnecting thousands of heterogeneous devices. As their popularity increases

day-by-day, the mobile ad hoc network (MANET) working group was charted in

1997 in order to discuss and develop solutions in this area. The MANET working

group defines a mobile ad hoc network as an autonomous system of mobile routers

(and associated hosts) connected by wireless links – the unions of which form an

arbitrary graph (MANET WG).

The nodes in an ad hoc network can dynamically join and leave the network

frequently, often without warning and possibly with interruption to other nodes’

communications. Typically, this type of networks may operate in standalone fashion

without necessitating any fixed infrastructure, or may be connected to the global

Internet.

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The absence of fixed infrastructure in MANETs requires individual nodes be

responsible for dynamically discovering which other mobile nodes they can directly

communicate with. In this respect, an ad hoc network can be considered to be a peer-

to-peer network allowing direct communication between any two nodes as long as

they are within the transmission range of each other, provided that adequate

transmission energy and desired radio propagation conditions exist at and between

the considered node-pair. Such communication between arbitrary end-points often

requires routing over multiple-hop wireless paths. In this context, each mobile node

can act as end terminal node (terminode) and/or forwarding (transit) node (Blazevic

et. al 2001).

Ad hoc networks are thus self-creating, self-organising and self-administrating. They

thence offer unique benefits and versatility for a variety of situations and

applications. Because of the abovementioned reasons, this kind of network is

expected to play important role in future commercial and military applications,

where mobile access to wired network is either ineffective or impossible. A few

potential examples include soldiers in a hostile environment, fast establishment of

communication infrastructure during law enforcement operations, setting up

communication in exhibitions, conferences, or sales presentations, operation of wall-

free (virtual) classrooms, connecting sensors scattered for biological detection, rare

animal tracking, space exploration, undersea operations, and temporary offices such

as campaign headquarters. In addition, home or small-office networking and

collaborative computing with laptop computers in small areas have recently emerged

as other major areas of potential commercial applications.

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However, despite their uniqueness, ad hoc networks pose numerous challenges and

generate new research problems when compared to fixed wireless networks. This

will be discussed in further detail in the following chapter.

This thesis aims to contribute to the area of QoS provisioning IEEE 802.11e based

MANETs. First, it provides a basic analysis of the problems caused by the lack of

QoS mechanisms in the current MANETs. Second, a study on existing differentiation

mechanisms for IEEE 802.11 protocols that explores their usability and importance

for voice and video applications are presented. Next, the thesis introduces a MAC

QoS provisioning mechanism which has built-in support for service guarantee for

multimedia voice and video applications. Finally, the performance of the developed

mechanism evaluated in simulation experiments compared to EDCA, the prevalent

MAC protocol in MANETs.

1.2 Scope

This thesis focuses on the improvement of QoS provisioning at MAC layer of

TCP/IP network model in the context of MANET. The main focus is on the operation

of HCCA polling scheme and its setup on top of multi channel medium. This

research combines the operations of EDCA and HCCA to form a new 802.11e

mechanism to provide a QoS support for real-time application in MANET.

Other QoS building blocks as queuing, scheduling and congestion avoidance are

outside the scope of this work.

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Figure 1.1 shows the research chart of this thesis. This thesis studies the QoS

challenges from the MAC layer perspective. The chart starts with defining the

network environment/topology to be studied i.e. MANET. The chart further defines

the OSI standard model layer to be researched and modified which is the MAC layer.

Then it describes the methodology layer of the research by trying to identify and

choose the method and the wireless technology to further improve or modify. It was

shown in figure 1.1 that combined EDCF/HCCA operation has been chosen as our

operating protocol at MAC layer. While EDCF is sufficient for best-effort traffic,

HCCA is required to ensure better resource allocation for voice and video traffic.

Another choice made is to use multi-channel instead of the common single channel

medium.

Earlier researches showed that the use of a single radio contention-based medium is

not suitable for multimedia traffic in multihop MANETs as the network performance

degrades when the network size increases and fails to meet the increased throughput

and delay requirements of new applications, hence the choice of multiple channels

was made. The methodology imports the QoS features in 802.11e into MANET and

adds resource reservation and admission control mechanism to maintain fairness. The

system analyzed by simulation using NS-2 targeting improvements in two

parameters namely throughput and MAC-delay (Kyasanur 2005) (Raniwala 2005).

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Figure 1.1: The Research Chart

Ad Hoc MANET Sensor Networks

Wireless LAN

MAC Physical Transport Routing

QoS 802.11e

Resource Reservation

Admission Control

EDCF/ HCCA

EDCF HCCA

Single Channel

Multi-Channel

MAC-Delay

Mathematical Analysis

Simulation Analysis

Throughput

QoS MAC mechanism for Multimedia Traffic in Mobile Ad Hoc Network (MANET)

1.3 Motivation

The basic challenge to overcome when dealing with a shared transmission medium is

how to control access to the communication channel. Medium access control (MAC)

provides this functionality, and therefore defines the rules for orderly access to the

shared medium. In this process, MAC plays a crucial role in the efficient and fair

sharing of the common communication medium and hence in the QoS provisioning.

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