Quality of Service and Resource Allocation in WiMAXFig Part 1 pdf

QUALITY OF SERVICE AND RESOURCE ALLOCATION IN WIMAX Edited by Roberto C... Quality of Service and Resource Allocation in WiMAX Edited by Roberto C.. Publishing Process Manager Tajana Je

QUALITY OF SERVICE

AND RESOURCE ALLOCATION IN WIMAX

Edited by Roberto C Hincapie

and Javier E Sierra

Quality of Service and Resource Allocation in WiMAX

Edited by Roberto C Hincapie and Javier E Sierra

work Any republication, referencing or personal use of the work must explicitly identify the original source

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Notice

Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher No responsibility is accepted for the accuracy of information contained in the published chapters The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book

Publishing Process Manager Tajana Jevtic

Technical Editor Teodora Smiljanic

Cover Designer InTech Design Team

First published January, 2012

Printed in Croatia

A free online edition of this book is available at www.intechopen.com

Additional hard copies can be obtained from orders@intechweb.org

Quality of Service and Resource Allocation in WiMAX,

Edited by Roberto C Hincapie and Javier E Sierra

p cm

978-953-307-956-1

Contents

Preface IX Part 1 Scheduling and Resource Allocation Algorithms 1

Chapter 1 Scheduling Mechanisms 3

Márcio Andrey Teixeira and Paulo Roberto Guardieiro Chapter 2 A Comprehensive Survey on

WiMAX Scheduling Approaches 25

Lamia Chaari, Ahlem Saddoud, Rihab Maaloul and Lotfi Kamoun Chapter 3 Scheduling Mechanisms with

Call Admission Control (CAC) and an Approach with Guaranteed Maximum Delay for Fixed WiMAX Networks 59

Eden Ricardo Dosciatti, Walter Godoy Junior and Augusto Foronda Chapter 4 Scheduling Algorithm and

Bandwidth Allocation in WiMAX 85

Majid Taghipoor, Saeid MJafari and Vahid Hosseini Chapter 5 Downlink Resource

Allocation and Frequency Reuse Schemes for WiMAX Networks 105

Nassar Ksairi

Chapter 6 Multi Radio Resource Management

over WiMAX-WiFi Heterogeneous Networks: Performance Investigation 129

Alessandro Bazzi and Gianni Pasolini

Chapter 7 A Cross-Layer Radio Resource

Management in WiMAX Systems 147

Sondes Khemiri Guy Pujolle

and Khaled Boussetta Nadjib Achir

VI Contents

Part 2 Quality of Service Models and Evaluation 175

Chapter 8 A Unified Performance Model

for Best-Effort Services in WiMAX Networks 177

Jianqing Liu, Sammy Chan and Hai L Vu

Chapter 9 A Mobile WiMAX Architecture with QoE

Support for Future Multimedia Networks 193

José Jailton, Tássio Carvalho, Warley Valente, Renato Frânces, Antônio Abelém, Eduardo Cerqueira and Kelvin Dias

Chapter 10 Evaluation of QoS and QoE in

Mobile WIMAX – Systematic Approach 217

Adam Flizikowski, Marcin Przybyszewski, Mateusz Majewski and Witold Hołubowicz

Part 3 WiMAX Applications and Multi-Hop Architectures 243

Chapter 11 Efficient Video Distribution over

WiMAX-Enabled Networks for Healthcare and Video Surveillance Applications 245

Dmitry V Tsitserov and Dmitry K Zvikhachevsky Chapter 12 Cross-Layer Application of Video

Streaming for WiMAX: Adaptive Protection with Rateless Channel Coding 273

L Al-Jobouri and M Fleury

Chapter 13 Public Safety Applications

over WiMAX Ad-Hoc Networks 291

Jun Huang, Botao Zhu and Funmiayo Lawal Chapter 14 Multihop Relay-Enhanced WiMAX Networks 319

Yongchul Kim and Mihail L Sichitiu Chapter 15 Cost Effective Coverage

Extension in IEEE802.16j Based Mobile WiMAX Systems 341

Se-Jin Kim, Byung-Bog Lee, Seung-Wan Ryu, Hyong-Woo Lee and Choong-Ho Cho Chapter 16 A WiMAX Network

Architecture Based on Multi-Hop Relays 359

Konstantinos Voudouris, Panagiotis Tsiakas, Nikos Athanasopoulos, Iraklis Georgas, Nikolaos Zotos and Charalampos Stergiopoulos

Preface

This book has been prepared to present state of the art on WiMAX Technology It has been constructed with the support of many researchers around the world, working on resource allocation, quality of service and WiMAX applications Such many different works on WiMAX, show the great worldwide importance of WiMAX as a wireless broadband access technology

This book is intended for readers interested in resource allocation and quality of service in wireless environments, which is known to be a complex problem All chapters include both theoretical and technical information, which provides an in depth review of the most recent advances in the field for engineers and researchers, and other readers interested in WiMAX

In the first section, readers will find chapters on resource allocation techniques, such as scheduling, call admission control, frequency reuse and cross-layer techniques The second section presents the evaluation of various models for ensuring the QoS for applications running on WiMAX networks Finally in the third section, applications for WiMAX are presented, with wireless mesh networks based on multi-hop and relay architectures

Roberto C Hincapie, PhD & Javier E Sierra, PhD

Universidad Pontificia Bolivariana, Medellín,

Colombia

Part 1

Scheduling and Resource Allocation Algorithms

1

Scheduling Mechanisms

Márcio Andrey Teixeira and Paulo Roberto Guardieiro

1Federal Institute of Education, Science and Technology of São Paulo,

2Faculty of Electrical Engineering, Federal University of Uberlândia,

Brazil

1 Introduction

The WiMAX technology, based on the IEEE 802.16 standards (IEEE, 2004) (IEEE, 2005), is a solution for fixed and mobile broadband wireless access networks, aiming at providing support to a wide variety of multimedia applications, including real-time and non-real-time applications As a broadband wireless technology, WiMAX has been developed with advantages such as high transmission rate and predefined Quality of Service (QoS) framework, enabling efficient and scalable networks for data, video, and voice However, the standard does not define the scheduling algorithm which guarantees the QoS required

by the multimedia applications The scheduling is the main component of the MAC layer that helps assure QoS to various applications (Bacioccola, 2010) The radio resources have to

be scheduled according to the QoS parameters of the applications Therefore, the choice of the scheduling algorithm for the WiMAX systems is very important There are several scheduling algorithms for WiMAX in the literature, however, studies show that an efficient, fair and robust scheduling algorithm for WiMAX systems is still an open research area (So-

in et al., 2010) (Dhrona et al., 2009) (Cheng et al., 2010)

The packets that cross the MAC layer are classified and associated with a service class The IEEE 802.16 standards define five service classes: Unsolicited Grant Service (UGS), extended real-time Polling Service (ertPS), real-time Polling Service (rtPS), non real-time Polling Service (nrtPS) and Best Effort (BE) Each service class has different QoS requirements and must be treated differently by the Base Station The scheduling algorithm must guarantee the QoS for both multimedia applications (real-time and non-real-time), whereas efficiently utilizing the available bandwidth

The rest of the chapter is organized as follows Section 2 presents the features of the WiMAX MAC layer and of the WiMAX scheduling classes The main components of the MAC layer are presented Then, the key issues and challenges existing in the development of scheduling mechanisms are shown, making a link between the scheduling algorithm and its implementation Section 3 provides a comprehensive classification of the scheduling mechanisms Then, the scheduling mechanisms are compared in accordance with the QoS requirement guarantee Section 4 describes the scheduling algorithms found in the literature

in accordance with the classification of the scheduling mechanisms provided in the Section

Quality of Service and Resource Allocation in WiMAX

4

3 Then, the performance evaluation of these algorithms is made Section 5 presents a synthesis table of the main scheduling mechanisms and highlights the main points of each

of them Section 6 does the final consideration of this chapter

2 WiMAX MAC scheduling and QoS: Issues and challenges

The major purpose of WiMAX MAC scheduling is to increase the utilization of network resource under limited resource situation In the WiMAX systems, the packet scheduling is implemented in the Subscriber Station (uplink traffic) and in the Base Station (downlink and uplink traffic) The Figure 1 shows the packets scheduling in the Base Station (BS) and in the Subscriber Station (SS) (Ma, 2009)

Fig 1 Packet scheduling in the BS and in the SS (Ma, 2009)

In the downlink scheduling, the BS has complete knowledge of the queue status and the BS

is the only one that transmits during the downlink subframe The data packets are broadcasted to all SSs and an SS only picks-up the packets destined to it The uplink

Scheduling Mechanisms 5 scheduling is more complex than downlink scheduling In the uplink scheduling, the input queues are located in the SSs and are hence separated from the BS So, the BS does not have any information about the arrival time of packets in the SSs queues

2.1 The uplink medium access

The BS is responsible for the whole medium control access for the different SSs The uplink medium access is based on request/grant mechanisms Firstly, the BS makes the bandwidth allocation so that the SSs can send their bandwidth request messages before the transmitting

of data over the medium This process is called polling The standard defines two main request/grant mechanisms: unicast polling and contention-based polling The unicast polling is the mechanism by which the BS allocates bandwidth to each SS to send its BW-REQ messages The BS performs the polling periodically After this, the SSs can send its BW-REQ messages as a stand-alone message in response to a poll from the BS or it can be piggy-backed in data packets The contention-based polling allows the SSs to send their bandwidth requests to the BS without being polled The SSs send BW-REQ messages during the contention period If multiple request messages are transmitted at the same time, collisions may occur There are other mechanisms that the SSs can use to request uplink bandwidth such as multicast polling, Channel Quality Indicator Channel (CQICH) (Lakkakorpi & Sayenko, 2009) etc Depending on the QoS and traffic parameters associated with a service, one or more of these mechanisms may be used by the SSs A comparison of these mechanisms is presented in (Chuck, 2010)

The choice of the bandwidth request and grant mechanisms has an impact directly on the scheduling delay parameter The scheduling delay parameter corresponds to the time interval between when the bandwidth is requested and when it is allocated The scheduling algorithms try to minimize this interval time in order to meet the time constraints of delay-sensitive applications Moreover, because the standard gives a choice among several bandwidth request mechanisms, it is important for each scheduling mechanism solution to define its own bandwidth request strategy

2.2 The WiMAX scheduling classes

The packets that cross the MAC layer are classified in connections At the MAC, each connection belongs to a single service class and is associated with a set of QoS parameters that quantify its characteristics The standard defines five QoS classes (Li et al., 2007):

 The Unsolicited Grant Service (UGS) receives unsolicited bandwidth to avoid excessive delay and has higher transmission priority among the other services This service supports constant bit rate (CBR) or fixed throughput connections such E1/T1 lines and voice over IP (VoIP) The BS uplink scheduler offers fixed size uplink (UL) bandwidth (BW) grants on a real-time periodic basis The QoS specifications are: Maximum sustained rate, Maximum latency tolerance, Jitter tolerance

 The extended real-time Polling Service (ertPS) also receives unsolicited bandwidth to avoid excessive delay However, the ertPS service can send bandwidth request messages to change the allocated resource This service is designed to support real-time multimedia applications that generate, periodically, variable size data packets such as VoIP services with silence suppression The BS uplink scheduler offers real-time uplink

Quality of Service and Resource Allocation in WiMAX

6

bandwidth request opportunities on a periodic basis, similar to UGS, but the allocations are made in a dynamic form, not fixed The QoS specifications are: Maximum sustained rate, Minimum reserved rate, Maximum latency tolerance, Jitter tolerance, Traffic priority

 The real-time Polling Service (rtPS) uses unicast polling mechanism and receives from

BS periodical grants in order to send its BW-REQ messages This service is designed to support variable-rate services (VBR) such as MPEG video conferencing and video streaming The BS uplink scheduler offers periodic uplink bandwidth request opportunities The QoS specifications are: Maximum sustained rate, Minimum reserved rate, Maximum latency tolerance, Jitter tolerance and Traffic priority

 The non-real time Polling Service (nrtPS) can use contention request opportunities or unicast request polling However, the nrtPS connections are polled on a regular basis to assure a minimum bandwidth So, the BS uplink scheduler provides timely uplink bandwidth request opportunities (in order of a second or less) (IEEE, 2005) This service

is designed to support applications that do not have delay requirements The QoS specifications are: Maximum sustained rate, Minimum reserved rate and Traffic priority

 The Best Effort (BE) service can use unicast or contention request opportunities However, the BS uplink scheduler does not specifically offer any uplink bandwidth opportunity This service does not have any QoS requirements

The Table 1 shows a comparison of WiMAX service classes Adapted from (So-in et al., 2010)

guaranteed latency for

real-time service

Bandwidth may not be utilized fully since allocations are granted regardless of current need

ertPS Optimal latency and data

overhead efficiency

Needs to use the polling mechanism (to meet the delay guarantee) and a mechanism to let the BS know when the traffic starts during the silent period rtPS Optimal data transport

efficiency

Requires the overhead of bandwidth request and the polling latency (to meet the delay guarantee) nrtPS Provides efficient service for

non-real-time traffics with

minimum reserved rate

long period of time

Table 1 Comparison of WiMAX Service classes (So-in et al., 2010)

Scheduling Mechanisms 7 The scheduling algorithm must guarantee the QoS for both multimedia applications (real-time and non-real-time), while efficiently utilizing the available bandwidth However, the scheduling algorithm for the service classes is not defined by the IEEE 802.16 standards

2.3 The scheduling and the link adaptation

The design of scheduling algorithms in WiMAX networks is highly challenging because the wireless communication channel is constantly varying (Pantelidou & Ephremides, 2009) The key issue to meet the QoS requirements in the WiMAX system is to allocate the resources among the users in a fair and efficient way, especially for video and voice transmission However, the amount of allocated resources depends on the Modulation and Coding Schemes (MCSs) used in the physical layer The aim of the MCSs is to maximize the data rate by adjusting transmission modes to channel variations The WiMAX supports a variety of MCSs and allows for the scheme to change on a burst-by-burst basis per link, depending on channel conditions The Figure 2 shows the processing units at MAC and PHY (Liu et al., 2006)

Fig 2 Processing units at MAC and PHY (Liu et al., 2006)

The MCS is determined in accordance with the Signal-to-Noise Ratio (SNR) and depends on two values:

 The minimum entry threshold: represents the minimum SNR required to start using more efficient MCS