5 GHZ CHANNEL CHARACTERIZATION FOR AIRPORT SURFACE AREAS AND VEHICLE-VEHICLE COMMUNICATION SYSTEMS A dissertation presented to the faculty of the Russ College of Engineering and Technology of Ohio University In partial fulfillment of the requirements for the degree Doctor of Philosophy Indranil Sen August 2007 This dissertation titled 5 GHZ CHANNEL CHARACTERIZATION FOR AIRPORT SURFACE AREAS AND VEHICLE-VEHICLE COMMUNICATION SYSTEMS by INDRANIL SEN has been approved for the School Electrical Engineering Computer Science and the Russ College of Engineering and Technology by David W. Matolak Associate Professor, School of Electrical Engineering and Computer Science Dennis Irwin Dean, College of Engineering and Technology Abstract SEN, INDRANIL, Ph.D., August 2007, Electrical Engineering 5 GHZ CHANNEL CHARACTERIZATION FOR AIRPORT SURFACE AREAS AND VEHICLE-VEHICLE COMMUNICATION SYSTEMS (416 pp.) Director of Dissertation: David W. Matolak We empirically characterize the 5 GHz channel for airport surface (AS) area and vehicle to vehicle (VTV) communication systems. The characterization consists of stochastic models for the channel impulse response, which focus on small-scale, and “medium,” or “meso-“scale effects. Motivation is provided by reviewing the growth in civil aviation and VTV communications, and by describing the utility of the 5 GHz band for these new communication systems. Further motivation arose from our literature survey, which revealed a pressing need for wideband stochastic channel models for these new applications in this band. Data measurement campaigns and environment descriptions are provided. For both the AS and VTV settings, classification schemes are developed. These schemes allow grouping AS and VTV environments into classes, and these classes are further divided into propagation regions, for which channel characteristics are statistically similar. A pre-processing framework to extract the most pertinent channel information from the measured data was developed. A propagation path loss model was also developed for the large airport class. Based upon our measured data, we deduced some unique propagation effects: severe, or “worse than Rayleigh,” fading, correlated scattering, and statistical non-stationarity (NS). To explain the severe fading phenomenon, we present two physical models that yield results in agreement with our measured data. For each propagation region of the AS and VTV classes, three different small scale fading models (denoted M1, M2, and M3) were developed. These models are applicable to different values of channel bandwidth, allow tradeoffs between the model’s implementation complexity and fidelity, and allow for the model user’s incorporation of statistical non-stationarity. Channel non-stationarity was modeled using two different random processes: the multipath component persistence process (for AS and VTV) models the finite lifetime associated with a multipath component, whereas the region persistence process (only AS) emulates the transition of the receiver from one propagation region to another. Each of these processes is based on a first-order Markov chain. The channel models were implemented in software using a new correlated multivariate Weibull random process generator. The model outputs were compared with the actual data using both time and frequency domain measures. Our NS model yields best agreement with the data, for all cases. We also present channel models for the cases when the AS transmitter is located at an airport field site. Approved: _____________________________________________________________ David W. Matolak Associate Professor, School of Electrical Engineering and Computer Science Acknowledgments There are quite a few people that I would like to thank for my wonderful experience as graduate student at Ohio University. First of all, I would like to express my sincere appreciation and gratitude for my advisor Dr. David Matolak. His in-depth knowledge of wireless communication and excellent suggestions have been an invaluable asset for me throughout my research. I really appreciate the fact that inspite of his busy schedule; he always found time to discuss my trivial questions and provided me insights on solving the issue on hand. Next, I would like to express my appreciation to my committee members, Dr. Jeffrey Dill, Dr. Frank Van Graas, Dr. Trent Skidmore, Dr. Dinh Van Huynh and Dr. Sergio Lopez. All of them have been extremely helpful throughout the course of this dissertation and I am grateful to them for that. I would also like to extend my sincere gratitude towards Dr. Roger Radcliff who believed in me and provided me with financial assistance through out my time as a PhD student. I would also like to thank Tammy Jordan for all her help during my stay as a graduate student with the electrical engineering department. I would also like to thank Dr. Joseph Essman for being on my written and oral comprehensive exams. Next, I would like to acknowledge Rafael D. Apaza of the FAA Aviation Research Office, Brian Kachmar of Analex Corporation and the airport facilities staff at MIA, JFK, and CLE for their support while gathering measurements for this project. During my stay at Athens, I made quite a few friends and they all have contributed in creating a wonderful experience for me over the past few years. I would like to thank Sumit Bhattacharya, Kamal Ganti and Irina Anitei for being wonderful support structures and also for the numerous “Grilling Sessions” which helped me relax after a week of intense research. Next, I would like to thank my lab-mates Wenhui Xiong, Beibei Wang, Nicholas Yaskoff and Jingtao Zhang for the numerous discussions regarding research, job hunt, politics, etc. They definitely provided a very friendly atmosphere in the MMCL lab and I will always miss those times and stimulating discussions. A special note of thanks for Wenhui and Nick who helped me collect measurements at the various airports. Lastly, I would like to thank my parents, sister, brother-in-law, fiancé and two wonderful nephews. Their support and love helped me believe in myself and concentrate on my dissertation. I am grateful to them for being a part of my life and I would like them to know that my dissertation is dedicated to all of them because without them it would have never been possible. 7 Table of Contents Page ABSTRACT....................................................................................................................... 3 ACKNOWLEDGMENTS ................................................................................................ 5 LIST OF TABLES .......................................................................................................... 11 LIST OF FIGURES ........................................................................................................ 14 LIST OF ACRONYMS AND OF ABBREVIATIONS................................................ 19 LIST OF SYMBOLS ...................................................................................................... 25 1 INTRODUCTION................................................................................................... 30 1.1 INTRODUCTION TO WIRELESS CHANNELS............................................................................................................. 30 1.2 AIRPORT SURFACE COMMUNICATIONS APPLICATIONS IN THE 5 GHZ BAND............................................................ 34 1.3 INTELLIGENT TRANSPORTATION SYSTEMS............................................................................................................. 36 1.4 DISSERTATION OBJECTIVES ................................................................................................................................38 1.5 DISSERTATION CONTRIBUTIONS .......................................................................................................................... 41 2 LITERATURE REVIEW ...................................................................................... 44 2.1 INTRODUCTION.................................................................................................................................................. 44 2.2 GENERIC CHANNEL MODELING .......................................................................................................................... 45 2.3 MEASUREMENT AND DATA PROCESSING TECHNIQUES .......................................................................................... 48 2.4 AIRPORT SURFACE AREA CHANNEL MODELS ....................................................................................................... 49 2.5 VEHICLE TO VEHICLE CHANNEL MODELS............................................................................................................ 55 2.6 SEVERE FADING ................................................................................................................................................ 59 2.7 WEIBULL FADING PROCESS................................................................................................................................62 2.8 NON STATIONARY CHANNEL MODELS.................................................................................................................. 64 3 MEASUREMENT CAMPAIGNS......................................................................... 73 3.1 EQUIPMENT DESCRIPTION.................................................................................................................................. 73 3.1.1 Channel Sounder .........................................................................................................................................................73