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 INTECHOPEN.COM Quality of Service and Resource Allocation in WiMAX http://dx.doi.org/10.5772/2454 Edited by Roberto C. Hincapie and Javier E. Sierra Contributors Eden Ricardo Dosciatti, Walter Godoy Jr., Augusto Foronda, Adam Dawid Flizikowski, Marcin Przybyszewski, Mateusz Majewski, Witold Hołubowicz, Nikolaos Zotos, Nikolaos Athanasopoulos, Konstantinos Voudouris, Panagiotis Tsiakas, Iraklis Georgas, Charalampos Stergiopoulos, Yongchul Kim, Mihail L. Sichitiu, Jose Jailton Junior, Tassio Carvalho, Warley Valente, Eduardo Cerqueira, Sondes Kallel Khemiri, Khaled Boussetta, Nadjib Achir, Guy Pujolle, Se-Jin Kim, Byung-Bog Lee, Seung-Wan Ryu, Hyong-Woo Lee, Choong-Ho Cho, Majid Taghipoor, Saeid Mohammadjafari, Sammy Chan, Jianqing Liu, Hai Vu, Marcio Teixeira, Paulo Guardieiro, Gianni Pasolini, Alessandro Bazzi, Jun Steed Huang, Botao Zhu, Funmilayo Lawal, Lamia Chaari, Ahlem Saddoud, Lotfi Kamoun, Rihab Maaloul, Nassar Ksairi, Dmitry Tsitserov, Dmitry Zvikhachevsky, Laith Al-Jobouri, Martin Fleury © The Editor(s) and the Author(s) 2012 The moral rights of the and the author(s) have been asserted. All rights to the book as a whole are reserved by INTECH. The book as a whole (compilation) cannot be reproduced, distributed or used for commercial or non-commercial purposes without INTECH’s written permission. 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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. First published in Croatia, 2012 by INTECH d.o.o. eBook (PDF) Published by IN TECH d.o.o. Place and year of publication of eBook (PDF): Rijeka, 2019. IntechOpen is the global imprint of IN TECH d.o.o. Printed in Croatia Legal deposit, Croatia: National and University Library in Zagreb Additional hard and PDF copies can be obtained from orders@intechopen.com Quality of Service and Resource Allocation in WiMAX Edited by Roberto C. Hincapie and Javier E. Sierra p. cm. ISBN 978-953-307-956-1 eBook (PDF) ISBN 978-953-51-6115-8 Selection of our books indexed in the Book Citation Index in Web of Science™ Core Collection (BKCI) Interested in publishing with us? Contact book.department@intechopen.com Numbers displayed above are based on latest data collected. For more information visit www.intechopen.com 4,100+ Open access books available 151 Countries delivered to 12.2% Contributors from top 500 universities Our authors are among the Top 1% most cited scientists 116,000+ International authors and editors 120M+ Downloads We are IntechOpen, the world’s leading publisher of Open Access books Built by scientists, for scientists Meet the editors Professor Roberto C. Hincapie received his PhD degree in Telecommunications Engineering from the Univer- sidad Pontificia Bolivariana, Medellin, Colombia in 2009. Currently, he is an Associate Professor at the same university, where he is also the director of GIDATI re- search group. His current research interests are Wireless Mesh Networks, resource allocation and OFDM wireless technologies such as WiMAX and LTE. He has taught courses in Traffic Engineering, Simulation and Design of Telecommunication systems. He has participated in several publications in indexed journals and addressed a number of key international conferences. Professor Javier E. Sierra received his PhD degree in Telecommunications Engineering from the Universidad Pontificia Bolivariana, Medellin, Colombia in 2009. Cur- rently, he is a professor at the Engineering Department of the same university. He works for GIDATI research group and Universidad Pontificia Bolivariana. He has partici- pated in various national and international conferences (IEEE, ACM), and has received awards, including the award for the best pa- per presented. He is also an author of several publications in indexed jour- nals. His biography has been included in the book Who’s Who in the World, 2010 edition, and Who’s Who in Science and Engineering by Marquis Who’s Who in the World. His research interests include wireless networks, net- work optimization, traffic grooming and optical transport networks. Contents Preface X I 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 X 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 1 Federal Institute of Education, Science and Technology of São Paulo, 2 Faculty 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). Service Class Pros Cons UGS No overhead. Meets 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 N/A BE Provides efficient service for BE traffic No service guarantee; some connections may starve for a 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. Quality of Service and Resource Allocation in WiMAX 8 The mandatory exit threshold: represents the minimum SNR required to start using a more robust MCS. The Table 2 shows the values of the receiver SNR assumptions which are proposed in Table 266 of IEEE 802.16e amendment of the standard (Aymen & Loutfi, 2008). Modulation Codification rate SNR(dB) BPSK 1/2 3.0 QPSK 1/2 6.0 3/4 8.5 16QAM 1/2 11.5 3/4 15.0 64QAM 2/3 19.0 3/4 21.0 Table 2. Values of the SNR (Aymen & Loutfi, 2008). The link adaptation mechanism allows the making of an adaptive modification of the burst profiles, adapting the traffic to a new radio condition. However, a new issue emerges: how to make an efficient scheduling of the SSs, located in different points away from the BS, sending data to different burst profiles, in accordance with the MCSs used for data transmission. This issue is important because the scheduler must guarantee the application’s QoS requirements and allocate the resources in a fair and efficient way. 2.3.1 The WiMAX system capacity The WiMAX system capacity determines the amount of data that can be delivered to and from the users (Dietze, 2009). There are several ways of quantifying the capacity of a wireless system. The traditional way of quantifying capacity is by calculating the data rate per unit bandwidth that can be delivered in a system. The OFDM symbol is a basic parameter used to calculate the data rate. The expression (1) is used to calculate the data rate (Nuaymi, 2007): Number of uncoded bits per OFDM symbol Data Rate OFDM symboltime (1) 1 Nsc d c Data Rate NFFT BW n G (2) Where: Nsc : is the number of subcarriers used for useful data transmission. In OFDM PHY, 192 subcarriers are used for useful data transmission whereas the total number of subcarriers is equal to 256. d : represents the number of bits per symbol of modulation. This number depends on the MCS used. c : represents the code rate of the Forward Error Correction (FEC).