Nurul Sarkar Chapman & Hall/CRC Computer & Information Science Series Improving the Performance of Wireless LANs A Practical Guide Improving the Performance of Wireless LANs A Practical Guide CHAPMAN & HALL/CRC COMPUTER and INFORMATION SCIENCE SERIES Series Editor: Sartaj Sahni ADVERSARIAL REASONING: COMPUTATIONAL APPROACHES TO READING THE OPPONENT’S MIND Alexander Kott and William M. McEneaney DELAUNAY MESH GENERATION Siu-Wing Cheng, Tamal Krishna Dey, and Jonathan Richard Shewchuk DISTRIBUTED SENSOR NETWORKS, SECOND EDITION S. Sitharama Iyengar and Richard R. Brooks DISTRIBUTED SYSTEMS: AN ALGORITHMIC APPROACH Sukumar Ghosh ENERGY-AWARE MEMORY MANAGEMENT FOR EMBEDDED MULTIMEDIA SYSTEMS: A COMPUTER-AIDED DESIGN APPROACH Florin Balasa and Dhiraj K. Pradhan ENERGY EFFICIENT HARDWARE-SOFTWARE CO-SYNTHESIS USING RECONFIGURABLE HARDWARE Jingzhao Ou and Viktor K. Prasanna FUNDAMENTALS OF NATURAL COMPUTING: BASIC CONCEPTS, ALGORITHMS, AND APPLICATIONS Leandro Nunes de Castro HANDBOOK OF ALGORITHMS FOR WIRELESS NETWORKING AND MOBILE COMPUTING Azzedine Boukerche HANDBOOK OF APPROXIMATION ALGORITHMS AND METAHEURISTICS Teofilo F. Gonzalez HANDBOOK OF BIOINSPIRED ALGORITHMS AND APPLICATIONS Stephan Olariu and Albert Y. Zomaya HANDBOOK OF COMPUTATIONAL MOLECULAR BIOLOGY Srinivas Aluru HANDBOOK OF DATA STRUCTURES AND APPLICATIONS Dinesh P. Mehta and Sartaj Sahni HANDBOOK OF DYNAMIC SYSTEM MODELING Paul A. Fishwick HANDBOOK OF ENERGY-AWARE AND GREEN COMPUTING Ishfaq Ahmad and Sanjay Ranka HANDBOOK OF PARALLEL COMPUTING: MODELS, ALGORITHMS AND APPLICATIONS Sanguthevar Rajasekaran and John Reif HANDBOOK OF REAL-TIME AND EMBEDDED SYSTEMS Insup Lee, Joseph Y-T. Leung, and Sang H. Son PUBLISHED TITLES HANDBOOK OF SCHEDULING: ALGORITHMS, MODELS, AND PERFORMANCE ANALYSIS Joseph Y.-T. Leung HIGH PERFORMANCE COMPUTING IN REMOTE SENSING Antonio J. Plaza and Chein-I Chang HUMAN ACTIVITY RECOGNITION: USING WEARABLE SENSORS AND SMARTPHONES Miguel A. Labrador and Oscar D. Lara Yejas IMPROVING THE PERFORMANCE OF WIRELESS LANs: A PRACTICAL GUIDE Nurul Sarkar INTRODUCTION TO NETWORK SECURITY Douglas Jacobson LOCATION-BASED INFORMATION SYSTEMS: DEVELOPING REAL-TIME TRACKING APPLICATIONS Miguel A. Labrador, Alfredo J. Pérez, and Pedro M. Wightman METHODS IN ALGORITHMIC ANALYSIS Vladimir A. Dobrushkin MULTICORE COMPUTING: ALGORITHMS, ARCHITECTURES, AND APPLICATIONS Sanguthevar Rajasekaran, Lance Fiondella, Mohamed Ahmed, and Reda A. Ammar PERFORMANCE ANALYSIS OF QUEUING AND COMPUTER NETWORKS G. R. Dattatreya THE PRACTICAL HANDBOOK OF INTERNET COMPUTING Munindar P. Singh SCALABLE AND SECURE INTERNET SERVICES AND ARCHITECTURE Cheng-Zhong Xu SOFTWARE APPLICATION DEVELOPMENT: A VISUAL C++ ® , MFC, AND STL TUTORIAL Bud Fox, Zhang Wenzu, and Tan May Ling SPECULATIVE EXECUTION IN HIGH PERFORMANCE COMPUTER ARCHITECTURES David Kaeli and Pen-Chung Yew VEHICULAR NETWORKS: FROM THEORY TO PRACTICE Stephan Olariu and Michele C. Weigle PUBLISHED TITLES CONTINUED Nurul Sarkar Improving the Performance of Wireless LANs A Practical Guide CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2014 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed on acid-free paper Version Date: 20130729 International Standard Book Number-13: 978-1-4665-6063-5 (Hardback) This book contains information obtained from authentic and highly regarded sources. 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Improving the performance of wireless LANs : a practical guide / author, Nurul Sarkar. pages cm -- (Chapman & Hall/CRC computer and information science series) Includes bibliographical references and index. ISBN 978-1-4665-6063-5 (alk. paper) 1. Wireless LANs. 2. Network performance (Telecommunication) I. Title. TK5105.78.S27 2014 004.6’8--dc23 2013028432 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com To my parents, my wife, Laila A. Sarkar, and my son, Hamidul I. Sarkar ix Contents Foreword, xxv Preface, xxvii Acknowledgments, xxxiii About the Author, xxxv Acronyms, xxxvii S ection i t heoretical B ackground c hapter 1 ◾ i ntroduction 3 Learning Outcomes 3 Introduction and Benefits of WLANs 3 WLAN Standards 5 Motivation for WLAN Performance Study 5 Methodology Adopted for WLAN Performance Study 7 Contribution and Structure of This Book 9 Further Reading 13 Books 13 Research Papers 13 Summary 13 Key Terms 14 Review Questions 14 Mini-Projects 14 x ◾ Contents c hapter 2 ◾ W ireleSS l ocal a rea n etWorkS 17 Learning Outcomes 17 Introduction 17 WLAN Architecture 18 WLAN versus Cellular Networks 20 WLAN Performance-Limiting Factors 21 IEEE 802.11 Physical Layer 22 Automatic Rate Fallback 24 Location-Dependent Effects 26 Capture Effect 26 Hidden and Exposed Station Problems 27 IEEE 802.11 Medium Access Control Methods 28 IEEE 802.11 DCF 29 IEEE 802.11 PCF 31 Shortcomings of 802.11 32 WLAN Performance Estimation Approaches 32 Further Reading 33 Books 33 Research Papers 33 Summary 34 Key Terms 34 Review Questions 35 Mini-Projects 35 c hapter 3 ◾ r adio p ropagation c haracteriSticS 37 Learning Outcomes 37 Introduction 37 Radio Propagation Mechanisms 38 Radio Propagation Environment: A Review of Literature 38 Signal Interference 41 Multipath Propagation 41 Attenuation 42 Contents ◾ xi Signal Quality: RSS, SNR, SIR, and BER 42 Received Signal Strength 42 Signal-to-Noise Ratio 43 Signal-to-Interference Ratio 43 Bit Error Rate 44 Further Reading 44 Books 44 Research Papers 44 Summary 44 Key Terms 45 Review Questions 45 Mini-Projects 45 c hapter 4 ◾ W ireleSS M ediuM a cceSS c ontrol p rotocolS 47 Learning Outcomes 47 Introduction 47 Wireless MAC Protocols: A Review of the Literature 48 Wireless MAC Protocol Classification 48 Contention-Based versus Contention-Free MAC Protocol 49 Representative MAC Protocols 50 Multiple Access with Collision Avoidance Protocol 52 Multiple Access with Collision Avoidance for Wireless Networks Protocol 53 Centralized Packet Reservation Multiple Access (C-PRMA) Protocol 53 Floor Acquisition Multiple Access and Group Allocation Multiple Access with Packet Sensing (GAMA-PS) Protocols 54 Simple Dynamic Protocol (SDP), Dynamic 802.11 and 802.11+ 54 Priority Unavoidable Multiple Access (PUMA) Protocol 55 TDMA-Based Randomly Addressed Polling (TRAP) Protocol 55 Fast Collision Resolution (FCR) 55 Interleaved Carrier Sense Multiple Access (ICSMA) Protocol 55 xii ◾ Contents Collision-Free MAC, Fair MAC, and 802.11 Distributed Foundation Wireless MAC (DFWMAC) 56 Carrier Sense Multiple Access with ID Countdown (CSMA/ IC) and Carrier Sense Multiple Access with Collision Prevention (CSMA/CP) Protocols 56 Concatenation and Piggybacking Mechanisms 57 Collision Detection (CD) MAC Protocol 57 New Backoff Algorithm 57 MAC Protocol Performance Issues 57 Design Issues for Wireless MAC Protocols 60 Influence of Radio Propagation on MAC Protocol Design 60 Effect of Network Performance on MAC Protocol Design 61 Further Reading 62 Books 62 Research Papers 62 Summary 62 Key Terms 63 Review Questions 63 Mini-Projects 64 c hapter 5 ◾ W ireleSS r outing p rotocolS 65 Learning Outcomes 65 Introduction 65 Properties of Routing Protocols 66 Design Issues of Routing Protocols 66 MANET Routing Approaches 68 Optimized Link State Routing 69 Dynamic Source Routing 69 Ad Hoc On-Demand Distance Vector 72 Temporally Ordered Routing Algorithm 75 Comparison of Routing Protocols 78 Performance of Routing Protocols 80 Performance Issues 82 Contents ◾ xiii A Proposal for Improving MANET Routing Performance 85 Further Reading 87 Books 87 Research Papers 89 Summary 89 Key Terms 89 Review Questions 89 Mini-Projects 90 c hapter 6 ◾ c roSS -l ayer d eSign for Wlan S 91 Learning Outcomes 91 Introduction 91 Definition of CLD 92 Motivation for CLD 92 Various Approaches to CLD 93 Strengths and Weaknesses of CLD Approaches 94 CLD Optimization: A Review of the Literature 95 Cross-Layer Design: A Survey and Taxonomy 95 TCP Path Recovery Notification (TCP-PRN) 95 Best Video Quality Using CLD 97 Rate Adaptation Solution 97 Joint Quality and Rate Adaptation 97 Opportunistic Cooperative MAC (OC-MAC) 97 Weighted Fair Scheduling Adaptive Rate Control Framework 98 Rate Optimization for Multicast Communications 98 Rate Adaptation and Payload Length 98 Cross-Layer Performance Evaluation Framework 98 Rate-Proportional 802.11 Fairness 99 Rayleigh Channel Predictability 99 Joint PHY-MAC Layer Design 99 Further Reading 100 xiv ◾ Contents Books 100 Research Papers 101 Summary 101 Key Terms 102 Review Questions 102 Mini-Projects 102 S ection ii e Mpirical S tudy c hapter 7 ◾ Effect of Radio Propagation Environments on WLAN Performance 107 Learning Outcomes 107 Introduction 108 The Environments Used 108 Environment A: Duthie Whyte Building 108 Environment B: AUT Tower 111 Environment C: Suburban House 111 Measurement Procedure and Resources Used 111 Measurement Results 115 Environment A 115 Experiment 1: Effect of Tx-Rx Orientation 115 Experiment 2: Effect of LOS Condition in the Basement 117 Experiment 3: Effect of Office Wall Partitions 118 Experiment 4: Effect of LOS Blockage 120 Experiment 5: Effect of Floors 121 Experiment 6: Effect of Single-Wall Separation 122 Experiment 7: Effect of Microwave Oven Interference 123 Environment B 125 Scenario 1: Ad Hoc Network 125 Scenario 2: Infrastructure Network 126 Environment C 128 Performance Comparison of Environments A, B, and C 129 Measurement Accuracy and Validation 130 Contents ◾ xv Further Reading 131 Books 131 Research Papers 131 Summary 131 Key Terms 132 Review Questions (scenario based) 132 Mini-Projects 133 c hapter 8 ◾ Performance of 802.11g in an Obstructed Office Space 135 Learning Outcomes 135 Introduction 135 Propagation Study 136 Measurement Environment and Procedure 136 Measurement Results and Discussion 138 Overall Observation and Discussion 139 Measurement Accuracy and Validation 140 Simulation Study 141 Modeling the Network 141 Simulation Results 143 Simulation Accuracy and Model Verification 145 System Implications 146 Further Reading 146 Books 146 Book Chapters 146 Research Papers 146 Summary 146 Key Terms 147 Review Questions 147 Mini-Projects 148 xvi ◾ Contents c hapter 9 ◾ Improving WLAN Performance by Modifying MAC Protocols 151 Learning Outcomes 151 Introduction 151 Previous Work on the Enhancement of 802.11 152 Description of the Proposed BUMA Protocol 154 Optimization of Buffer Unit Length 157 Strengths and Weaknesses 158 Protocol Overhead and Throughput Analysis 158 Discussion and Interpretation 165 Performance Evaluation 165 Simulation Environment and Parameters 166 Modeling Assumptions 166 Simulation Results and Comparison 168 Throughput Performance 168 Delay Performance 170 MDT Fairness 170 Packet Drop Ratio 177 Simulation Model Verification 177 Implementation 177 Further Reading 179 Books 179 Book Chapters 179 Research Papers 179 Summary 179 Key Terms 180 Review Questions 181 Mini-Projects 181 c hapter 10 ◾ Effect of AP Configuration and Placement on WLAN Performance 183 Learning Outcomes 183 Contents ◾ xvii Introduction 183 AP Configuration Methods 184 Measurement Procedure and Resources Used 188 Results and Discussion for AP Configuration 189 Measurement Accuracy and Validation 191 Implications for AP Configuration 191 Experiment Details for AP Placement 192 Results and Discussion for AP Placement 193 Semi-LOS Conditions 193 Non-LOS Conditions 194 Simulation Study 196 Implications for AP Placement 198 Further Reading 200 Books 200 Research Papers 200 Summary 200 Key Terms 200 Review Questions 201 Mini-Projects 201 c hapter 11 ◾ Effect of Routing Protocols on WLAN Performance 203 Learning Outcomes 203 Introduction 203 Performance Study of MANET Routing Protocols 204 Network Scenarios 204 Modeling Assumptions 205 Simulation Environment and Parameter Settings 206 Modeling the Network 206 Experiment’s Results 209 Impact of Network Size (Small, Medium, and Large) 209 xviii ◾ Contents Scenario 1: Small-Sized Network (N = 10, NS = 5 m/s, PL = 1,000 bytes) 209 Scenario 2: Medium-Sized Network (N = 50, NS = 5 m/s, PL = 1,000 bytes) 211 Scenario 3: Large-Sized Network (N = 100, NS = 5 m/s, PL = 1,000 bytes) 214 Impact of Increasing Node Speed 216 Scenario 4: Varying Node Speed in a Small-Sized Network (N = 10, NS = 20 and 30 m/s, PL = 1,000 bytes) 217 Scenario 5: Varying Node Speed in a Medium-Sized Network (N = 50, NS = 20 and 30 m/s, PL = 1,000 bytes) 220 Scenario 6: Varying Node Speed in a Large-Sized Network (N = 100, NS = 20 and 30 m/s, PL = 1,000 bytes) 222 Impact of Increasing Traffic Load 226 Scenario 7: Varying Traffic Load in a Small-Sized Network (N = 10, NS = 30 m/s, PL = 5,000 and 50,000 bytes) 226 Scenario 8: Varying Traffic Load in a Medium-Sized Network (N = 50, NS = 30 m/s, PL = 5,000 and 50,000 bytes) 230 Scenario 9: Varying Traffic Load in a Large-Sized Network (N = 100, NS = 30 m/s, PL = 5,000 and 50,000 bytes) 234 Comparative Analysis 237 Overall Observation and Interpretations 240 Effect of Network Size 242 Effect of Node Mobility 243 Effect of Packet Length (Traffic Load) 244 Validation of Simulation Results 245 Further Reading 246 Books 246 Research Papers 246 Summary 246 Key Terms 247 Review Questions 247 Mini-Projects 247 Contents ◾ xix c hapter 12 ◾ Improving WLAN Performance Using CLD Optimization 249 Learning Outcomes 249 Introduction 249 Effect of Channel BER on WLAN Performance 250 Relationship between BER and FER 251 Implementation of BER in Ns-2.31 252 Performance Results 253 Comparative Analysis 256 Impact of BER on Network Throughput 257 Impact of BER on Packet Delay 258 Impact of BER on Network Fairness 259 Impact of BER on Packet Drop Ratio 259 Proposed PHY-MAC Layer Design Framework 260 Cross-Layer Design Algorithms 262 Benefits and Practical Implications of the Proposed CLD Method 264 Performance Evaluation 266 Simulation Results and Comparison 266 Overall Observations and Interpretations 269 Simulation Model Verification 270 Further Reading 270 Books 270 Research Papers 270 Summary 270 Key Terms 271 Review Questions 272 Mini-Projects 272 c hapter 13 ◾ Effect of Traffic Distribution on WLAN Performance 273 Learning Outcomes 273 Introduction 273