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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
This is a pioneering textbook on the comprehensive description of AeroMACS technology. It also presents the process of developing a new technology based on an established standard, in this case IEEE802.16 standards suite. The text introduces readers to the field of airport surface communications systems and provides them with comprehensive coverage of one the key components of the Next Generation Air Transportation System (NextGen); i.e., AeroMACS. It begins with a critical review of the legacy aeronautical communications system and a discussion of the impetus behind its replacement with network-centric digital technologies. It then describes wireless mobile channel characteristics in general, and focuses on the airport surface channel over the 5GHz band. This is followed by an extensive coverage of major features of IEEE 802.16-2009 Physical Layer (PHY)and Medium Access Control (MAC) Sublayer. The text then provides a comprehensive coverage of the AeroMACS standardization process, from technology selection to network deployment. AeroMACS is then explored as a short-range high-data-throughput broadband wireless communications system, with concentration on the AeroMACS PHY layer and MAC sublayer main features, followed by making a strong case in favor of the IEEE 802.16j Amendment as the foundational standard for AeroMACS networks. AeroMACS: An IEEE 802.16 Standard-Based Technology for the Next Generation of Air Transportation Systems covers topics such as Orthogonal Frequency Division Multiple Access (OFDMA), coded OFDMA, scalable OFDMA, Adaptive Modulation-Coding (AMC), Multiple-Input Multiple-Output (MIMO) systems, Error Control Coding (ECC) and Automatic Repeat Request (ARQ) techniques, Time Division Duplexing (TDD), Inter-Application Interference (IAI), and so on. It also looks at future trends and developments of AeroMACS networks as they are deployed across the world, focusing on concepts that may be applied to improve the future capacity. In addition, this text: * Discusses the challenges posed by complexities of airport radio channels as well as those pertaining to broadband transmissions * Examines physical layer (PHY) and Media Access Control (MAC) sublayer protocols and signal processing techniques of AeroMACS inherited from IEEE 802.16 standard and WiMAX networks * Compares AeroMACS and how it relates to IEEE 802.16 Standard-Based WiMAX AeroMACS: An IEEE 802.16 Standard-Based Technology for the Next Generation of Air Transportation Systems will appeal to engineers and technical professionals involved in the research and development of AeroMACS, technical staffers of government agencies in aviation sectors, and graduate students interested in standard-based wireless networking analysis, design, and development.
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CONTENTS
Cover
Series Page
Title Page
Copyright
Dedication
Preface
1 Synopsis of Chapters
2 The Audience
Acknowledgments
Acronyms
Chapter 1: Airport Communications from Analog AM to AeroMACS
1.1 Introduction
1.2 Conventional Aeronautical Communication Domains (Flight Domains)
1.3 VHF Spectrum Depletion
1.4 The ACAST Project
1.5 Early Digital Communication Technologies for Aeronautics
1.6 Selection of a Communications Technology for Aeronautics
1.7 The National Airspace System (NAS)
1.8 The Next Generation Air Transportation Systems (NextGen)
1.9 Auxiliary Wireless Communications Systems Available for the Airport Surface
1.10 Airport Wired Communications Systems
1.11 Summary
References
Chapter 2: Cellular Networking and Mobile Radio Channel Characterization
2.1 Introduction
2.2 The Crux of the Cellular Concept
2.3 Cellular Radio Channel Characterization
2.4 Challenges of Broadband Transmission over the Airport Surface Channel
2.5 Summary
References
Chapter 3: Wireless Channel Characterization for the 5 GHz Band Airport Surface Area*
3.1 Introduction
3.2 Statistical Channel Characterization Overview
3.3 Channel Effects and Signaling
3.4 Measured Airport Surface Area Channels
3.5 Airport Surface Area Channel Models
3.6 Summary
References
Chapter 4: Orthogonal Frequency-Division Multiplexing and Multiple Access
4.1 Introduction
4.2 Fundamental Principles of OFDM Signaling
4.3 Coded Orthogonal Frequency-Division Multiplexing: COFDM
4.4 Performance of Channel Coding in OFDM Networks
4.5 Orthogonal Frequency-Division Multiple Access: OFDMA
4.6 Scalable OFDMA (SOFDMA)
4.7 Summary
References
Chapter 5: The IEEE 802.16 Standards and the WiMAX Technology
5.1 Introduction to the IEEE 802.16 Standards for Wireless MAN Networks
5.2 The Evolution and Characterization of IEEE 802.16 Standards
5.3 WiMAX: an IEEE 802.16-Based Technology
5.4 Summary
References
Chapter 6: Introduction to AeroMACS
6.1 The Origins of the AeroMACS Concept
6.2 Defining Documents in the Making of AeroMACS Technology
6.3 AeroMACS Standardization
6.4 AeroMACS Services and Applications
6.5 AeroMACS Prototype Network and Testbed
6.6 Summary
References
Chapter 7: AeroMACS Networks Characterization
7.1 Introduction
7.2 AeroMACS Physical Layer Specifications
7.3 Spectrum Considerations
7.4 Spectrum Sharing and Interference Compatibility Constraints
7.5 AeroMACS Media Access Control (MAC) Sublayer
7.6 AeroMACS Network Architecture and Reference Model
7.7 Aeronautical Telecommunications Network Revisited
7.8 AeroMACS and the Airport Network
7.9 Summary
References
Chapter 8: AeroMACS Networks Fortified with Multihop Relays
8.1 Introduction
8.2 IEEE 802.16j Amendment Revisited
8.3 Relays: Definitions, Classification, and Modes of Operation
8.4 Regarding MAC Layers of IEEE 802.16j and NRTS
8.5 Challenges and Practical Issues in IEEE 802.16j-Based AeroMACS
8.6 Applications and Usage Scenarios for Relay-Augmented Broadband Cellular Networks
8.7 IEEE 802.16j-Based Relays for AeroMACS Networks
8.8 Radio Resource Management (RRM) for Relay-Fortified Wireless Networks
8.9 The Multihop Gain
8.10 Interapplication Interference (IAI) in Relay-Fortified AeroMACS
8.11 Making the Case for IEEE 802.16j-Based AeroMACS
8.12 Summary
References
Index
End User License Agreement
List of Tables
Table 1.1
Table 1.2
Table 1.3
Table 1.4
Table 1.5
Table 2.1
Table 2.2
Table 2.3
Table 2.4
Table 2.5
Table 3.1
Table 3.2
Table 3.3
Table 3.4
Table 3.5
Table 3.6
Table 3.7
Table 3.8
Table 3.9
Table 4.1
Table 4.2
Table 4.3
Table 4.4
Table 4.5
Table 4.6
Table 5.1
Table 5.2
Table 5.3
Table 5.4
Table 5.5
Table 5.6
Table 5.7
Table 5.8
Table 5.9
Table 6.1
Table 6.2
Table 6.3
Table 6.4
Table 6.5
Table 6.6
Table 6.7
Table 6.8
Table 6.9
Table 6.10
Table 6.11
Table 6.12
Table 6.13
Table 6.14
Table 7.1
Table 7.2
Table 7.3
Table 7.4
Table 7.5
Table 7.6
Table 7.7
Table 7.8
Table 7.9
Table 7.10
Table 7.11
Table 7.12
Table 7.13
Table 7.14
Table 8.1
Table 8.2
Table 8.3
Table 8.4
List of Illustrations
Figure 1.1
Figure 2.1
Figure 2.2
Figure 2.3
Figure 2.4
Figure 2.5
Figure 2.6
Figure 2.7
Figure 2.8
Figure 2.9
Figure 2.10
Figure 2.11
Figure 2.12
Figure 2.13
Figure 2.14
Figure 2.15
Figure 2.16
Figure 2.17
Figure 2.18
Figure 2.19
Figure 2.20
Figure 2.21
Figure 2.22
Figure 2.23
Figure 3.1
Figure 3.2
Figure 3.3
Figure 3.4
Figure 3.5
Figure 3.6
Figure 3.7
Figure 3.8
Figure 4.1
Figure 4.2
Figure 4.3
Figure 4.4
Figure 4.5
Figure 4.6
Figure 4.7
Figure 4.8
Figure 4.9
Figure 4.10
Figure 4.11
Figure 5.1
Figure 5.2
Figure 5.3
Figure 5.4
Figure 5.5
Figure 5.6
Figure 5.7
Figure 5.8
Figure 5.9
Figure 5.10
Figure 5.11
Figure 5.12
Figure 5.13
Figure 5.14
Figure 6.1
Figure 6.2
Figure 6.3
Figure 7.1
Figure 7.2
Figure 7.3
Figure 7.4
Figure 7.5
Figure 7.6
Figure 7.7
Figure 7.8
Figure 7.9
Figure 7.10
Figure 7.11
Figure 7.12
Figure 7.13
Figure 7.14
Figure 8.1
Figure 8.2
Figure 8.3
Figure 8.4
Figure 8.5
Figure 8.6
Figure 8.7
Figure 8.8
Figure 8.9
Figure 8.10
Figure 8.11
Figure 8.12
Figure 8.13
Guide
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IEEE Press
445 Hoes Lane
Piscataway, NJ 08854
IEEE Press Editorial Board
Ekram Hossain, Editor in Chief
Giancarlo Fortino
Andreas Molisch
Linda Shafer
David Alan Grier
Saeid Nahavandi
Mohammad Shahidehpour
Donald Heirman
Ray Perez
Sarah Spurgeon
Xiaoou Li
Jeffrey Reed
Ahmet Murat Tekalp
AeroMACS
An IEEE 802.16 Standard-Based Technology for the Next Generation of Air Transportation Systems
Behnam Kamali
Sam Nunn Eminent Scholar of Telecommunications and
Professor of Electrical and Computer Engineering
Mercer University
Macon, GA
This edition first published 2019
© 2019 the Institute of Electrical and Electronics Engineers, Inc.
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Library of Congress Cataloging-in-Publication Data
ISBN: 9781119281108
This book is dedicated to the memory of my father, Abdul Hossain Kamali (1915–1973), who was taken away from me unexpectedly, but his quest for knowledge, his enthusiasm for technology, and his insistence on the independent search for truth have remained with me and inspired me.
Preface
Civil aviation plays a major role in driving sustainable global and national economic and social development. During the year 2015, civil aviation created 9.9 million jobs inside the industry, and directly and indirectly supported the employment of 62.7 million people around the world. The total global economic impact of civil aviation was $2.7 trillion (including the effects of tourism). In the same year, approximately 3.6 billion passengers were transported through air. The volume of freight carried via air reached 51.2 million tons. Today, the value of air-transported goods stands at $17.5 billion per day. Accordingly, in the year 2015, approximately 3.5% of global GDP was supported by civil aviation. Research conducted in the United States suggests that every $100 million dollars invested in aerospace yields an extra $70 million in GDP year after year1. In addition to economic prosperity, civil aviation brings about a number of social and human relation benefits, ranging from swift delivery of health care, emergency services, and humanitarian aid, to the promotion of peace and friendship among various groups of people through trade, leisure, and cultural experiences and exchanges.
The global air transportation system is a worldwide network, consisting of four components of airport and airport infrastructures, commercial aircraft operators, air navigation service providers, and the manufacturers of aircraft and associated components. The airport component plays a central role in air traffic management, air traffic control, and the management of national and global airspace systems. From the technical point of view air transportation operation is centered around three elements of communications, navigation, and surveillance. The safety of air transportation is critically linked to the availability of reliable aeronautical communication systems that support all aspects of air operations and air traffic management, including navigation and surveillance. Owing to the fact that flight safety is the highest priority in aviation, extreme measures must be taken to protect the aeronautical communication systems against harmful interference, malfunction, and capacity limitation.
In the early days of commercial aviation, the 1940s, analog AM radio over VHF band was adopted for aeronautical communications. This selection was made mostly for the reason that analog AM was the only fully developed and proven radio communications technology at the time. However, by the late 1980s, spectrum congestion in aeronautical VHF band, due to rapid growth in both commercial and general sectors of civil aviation, became a concern for the aviation community in the United States and in Europe. The concerns about inability of the legacy system to safely manage future levels of air traffic, called for modernization of air transportation systems. This in turn led to the initiatives of Next Generation Air Transportation System Integrated Plan (NextGen) in the United States, and European Commission Single European Sky ATM Research (SESAR) in Europe. A joint FAA-EUROCONTROL technology assessment study on communications for future aviation systems had already come to the conclusion that no single communication technology could satisfy all physical, operational, and functional requirements of various aeronautical transmission domains. Based on recommendations made by that study, a broadband wireless mobile communications technology based on IEEE 802.16e (Mobile WiMAX) was selected for airport surface domain, leading to the advent of aeronautical mobile airport communications system, AeroMACS, the subject of focus in this book.
Over the past few years AeroMACS has evolved from a technology concept to a deployed operating communications network over a number of major U.S. airports. Projections are that AeroMACS will be deployed across the globe by the year 2020. It is worth noting that AeroMACS, as a new broadband data link able to support the ever-expanding air traffic management communications requirements, is emerging out of the modernization initiatives of NextGen and SESAR, and therefore should be considered to be an integral and enabling part of both NextGen and SESAR visions.
The main feature of this book is its pioneering focus on AeroMACS, representing, perhaps, the first text written entirely on the technology and how it relates to its parental standards (although book chapters on the subject have been published previously). The text is prepared, by and large, from a system engineering perspective, however, it also places emphasis on the description of IEEE 802.16e standards and how they can be tied up with communications requirements on the airport surface. A second contribution that this book aspires to make; when viewed on the whole, is to provide a complete picture of the overall process of how a new technology is developed based on an already established standard, in this case IEEE 802.16e standards. AeroMACS, like its parent standards, mobile WiMAX and IEEE 802.16-2009 WirelessMAN, is a complex technology that is impossible to fully describe in a few hundred pages. Nonetheless, it is hoped that this book will be able to provide an overall understanding of several facets of this fascinating technology that will be a key component of modern global air transportation systems. Another feature of this text is the simplicity of the language that is used for the description of complicated concepts. Efforts have also been made, to the extent possible and despite all the challenges, to make this book self-contained. To this end, review chapters are included and a large number of footnotes are provided in each chapter.
1 Synopsis of Chapters
This book, for the most part, reflects the results of the author's research activities in the field of aeronautical communications in conjunction with several summer research fellowships at NASA Glenn Research Center. The book consists of eight chapters. Chapter 1 presents an introduction to the applications of wireless communications in the airport environment. The chapter portrays a continuous picture of the evolution of airport surface communications techniques from the legacy VHF analog AM radio, to the appearance of digital communications schemes for various airport surface functionalities, and to the making of the AeroMACS concept. The rationales and the reasons behind the emergence of AeroMACS technology are described. The large arenas over which AeroMACS will operate, that is, the National Airspace System (NAS) and the International Airspace System, are concisely overviewed. The Federal Aviation Administration's NextGen and European SESAR programs, planned to transform and modernize air transportation, are discussed as well. Auxiliary wireless and wireline systems for airport surface communications, including airport fiber optic cable loop system, are briefly covered in the conclusion.
In modern wireless communication theory, a formidable challenge is the integration of an astonishing breath of topics that are tied together to provide the necessary background for thorough understanding of a wireless technology such as AeroMACS. It is no longer possible to separate signal processing techniques, such as modulation and channel coding, from antenna systems (traditionally studied as a topic in electromagnetic theory), and from networking issues involving physical layer and medium access control sublayer protocols. To this end, Chapter 2 is the first of the three review chapters in which two topics of cellular networking and wireless channel characterizations are addressed. The main objective for this and other review chapters is to ensure, as much as possible, that the text is self-contained. This approach is conducive to the understanding of the cellular architecture of the network and the challenges posed by airport surface radio channel in design, implementation, and deployment stages of AeroMACS systems.
Chapter 3, authored by Dr. David Matolak of the University of South Carolina, is dedicated to the airport surface radio channel characterization over the 5 GHz band. The chapter commences with describing the motivation and the need for this topic, followed by some background on wireless channels and modeling, and specific results for the airport surface channel. An extensive airport surface area channel measurement campaign is summarized. Example measurement results for RMS delay spread, coherence bandwidth, and small-scale fading Rician K-factors are provided. Detailed airport surface area channel models over the 5 GHz band, in the form of tapped-delay lines, are then presented.
Chapter 4 is the second review chapter, focusing on orthogonal frequency-division multiplexing (OFDM), coded OFDM, orthogonal frequency-division multiple access (OFDMA), and scalable OFDMA (SOFDMA). OFDMA is an access technology that offers significant advantages for broadband wireless transmission over its rival technologies such as CDMA. Accordingly, it is shared by a number of contemporary wireless telecommunication networks, including IEEE 802.16-Std-based networks such as WiMAX and AeroMACS. The primary advantage of OFDMA over rival access technologies is the ability of OFDM to convert a wideband frequency selective fading channel to a series of narrowband flat fading channels. This is the mechanism by which frequency selective fading effects of hostile multipath environments, such as the airport surface channel, are mitigated or eliminated altogether. Performance of channel coding in OFDM, that is, modulation–coding combination, is explored in this chapter, providing some background for understanding of adaptive modulation coding (AMC) scheme discussed in later chapters. Scalable OFDMA, which presents a key feature of mobile WiMAX networks, is covered in some detail.
Chapter 5 provides a brief review on IEEE 802.16-2009 and IEEE 802.16j-2009 standards as well as an overview on Worldwide Interoperability for Microwave Access (WiMAX); an IEEE 802.16-standard-based broadband access solution for wireless metropolitan area networks. AeroMACS mandatory and optional protocols are a subset of those inherited by mobile WiMAX from IEEE 802.16e standards. The main purpose of this review chapter is to provide technical background information on various algorithms and protocols that support AeroMACS networks. A high point of WiMAX technology is the fact that only physical (PHY) layer and medium access control (MAC) sublayer protocols have been defined while the higher layer protocols and the core network architecture are left unspecified to be filled by other technologies such as IP network architecture. The backbone of WiMAX technology is formed by OFDMA, multiple-input multiple-output (MIMO) concept, and IP architecture, all inherited by AeroMACS networks.
Chapter 6 is entirely dedicated to AeroMACS, providing an introduction to information related to the creation, standardization, and test and evaluation (through test beds) of this aviation technology. The core of this chapter is the AeroMACS standardization process that starts with technology selection. In contrast with assembling a proprietary dedicated technology, AeroMACS is constructed based on an interoperable version of IEEE 802.16-2009 standards (mobile WiMAX). The advantages of using an established standard are listed in the chapter. The IEEE 802.16e standard brings with itself a large number of PHY layer and MAC sublayer optional and mandatory protocols to select from for any driven technology. The WiMAX Forum System Profile Version 1.09, which assembles a subset of the IEEE standard protocols together, is such a technology that was selected as the parent standard for AeroMACS. Based on this selection, RTCA has developed a profile for AeroMACS. An overview of AeroMACS profile is presented in Chapter 6. Standards and Recommended Practices (SARPS) was developed almost simultaneously with the AeroMACS Profile by RTCA and EUROCAE. The last pieces of standardization process for AeroMACS to follow, as the chapter explains, were Minimum Operation Performance Standards (MOPS) and Minimum Aviation System Standards (MASPS). Finally, the AeroMACS standardization documents became a source for developments of an AeroMACS technical manual and an installation guide document. Potential airport surface services and functionalities that may be carried by AeroMACS are also addressed in Chapter 6. The chapter elaborates on AeroMACS test bed configuration and summarizes the early test and evaluation results, as well.
Chapter 7 explores AeroMACS as a short-range high-aggregate-data-throughput broadband wireless communications system, and concentrates on the detailed characterization of AeroMACS PHY layer and MAC sublayer features. AeroMACS main PHY layer feature is its multipath resistant multiple access technology, OFDMA, which allows 5 MHz channels within the allocated ITU-regulated aeronautical C-band of 5091–5150 MHz. The duplexing method is TDD, which enables asymmetric signal transmission over uplink (UL) and downlink (DL) paths. Adaptive modulation and coding (AMC) is another key physical layer feature of AeroMACS network. AMC allows for a proper combination of a modulation and coding schemes commensurate with the channel conditions. Multiple-input multiple-output (MIMO) and smart antenna systems are another PHY layer feature of AeroMACS networks. The chapter also discusses AeroMACS MAC sublayer. In particular, scheduling, QoS, ARQ system, and handover (HO) procedure are described. AeroMACS network architecture and Network Reference Model (NRM) are discussed. It is explained that AeroMACS is planned to be an all-IP network that supports high-rate packet-switched air traffic control (ATC) and Aeronautical Operational Control (AOC) services for efficient and safe management of flights, while providing connectivity to aircraft, operational support vehicles, and personnel within the airport area. Finally, the chapter highlights the position and the role of the AeroMACS network within the larger contexts of the Airport Network and the global Aeronautical Telecommunications Network (ATN).
The core idea of Chapter 8 is the demonstration of the fact that the IEEE 802.16j Amendment is highly feasible to be utilized as the foundational standard upon which AeroMACS networks are developed. This amendment enables the network designer to use the multihop relay as yet another design option in their device arsenal set. The chapter contains a great deal of information regarding the applications and usage scenarios for multihop relays in AeroMACS networks. Since the C-band spectrum allocated for AeroMACS is shared by other applications, interapplication interference (IAI) becomes a critical issue. It is shown, through a preliminary simulation study, that deployment of IEEE 802.16j AeroMACS poses no additional IAI to coallocated applications. An important consideration, given the AeroMACS constraints in both bandwidth and power, is how to increase AeroMACS capacity for accommodation of all assigned existing and potential future fixed and mobile services. This chapter demonstrates that gains that can be derived from the addition of IEEE 802.16j multihop relays to the AeroMACS standard can be exploited to improve capacity or to extend radio outreach of the network with no additional spectrum required. Hence, it is shown that it would make sense to allow the usage of relays, at least as an option, in AeroMACS networks. Furthermore, it is pointed out that it would always be possible to incorporate IEEE 802.16j standards into AeroMACS networks, even if the network is originally rolled out as an IEEE 802.16-2009-based network. The chapter introduces the key concept of “multihop gain” with a detailed analysis that quantifies this gain for a simple case. The chapter concludes with a strong case made in favor of IEEE 802.16j-based AeroMACS networks.
2 The Audience
This book can serve as a professional text assisting experts involved in research, development, deployment, and installation of AeroMACS systems. It can also be used as an academic textbook in wireless communications and networking, with case study application of WiMAX and AeroMACS, for a senior level undergraduate course or for a graduate level course in Electrical Engineering, Computer Engineering, and Computer Science programs.
The specific list of professional groups and individuals who may benefit from this text includes engineers and technical professionals involved in the R&D of AeroMACS systems, technical staff of government agencies working in aviation sectors, technical staff of private aviation firms all over the world involved in manufacturing of AeroMACS equipment, engineers and professionals who are interested or active in the design of standard-based wireless networks, and new researchers in wireless network design.
Acknowledgments
Although composed by a single author (or few authors), technical texts are drawn from the contributions of a large number of experts and the immense quantity of literature that they have created. I would like to acknowledge the groundbreaking research and development efforts of many researchers and engineers in the aviation industry, research institutions, academia, and national and international standardization bodies, whose contributions were instrumental in creating the groundwork for this book. In particular, I am appreciative to NASA Glenn Research Center's Communication, Control, and Instrumentation group.
I am deeply grateful to Robert J. Kerczewski of NASA Glenn Research Center for introducing me to AeroMACS technology and providing me with the opportunity to conduct research in AeroMACS area during my several summer research fellowships at NASA Glenn, and for being so generous with his time for discussion and exchange of ideas. Special thanks and appreciation is extended to Dr. David W. Matolak of the University of South Carolina for contributing Chapter 3 on the key topic of airport channel characterization over the 5 GHz band. I would also like to thank my NASA colleagues Rafael Apaza and Dr. Jeffery Wilson for sharing their insights on AeroMACS technology.
Special note of gratitude goes to John Wiley & Sons, Inc. publishing team, in particular to my editor, Mary Hatcher, for her continuous assistance and support for this book from proposal to production. I am also grateful to anonymous reviewers for their careful reading of the manuscript and their insightful comments and suggestions that have improved the quality of this book.
I would also like to recognize and appreciate the assistance that I have received from my former graduate student Laila Wise, who meticulously plotted some of the curves that I have included in Chapter 2. Last but not the least, I wish to express my appreciation to my life partner, Angela J. Manson, for her nonstop encouragement, patience, affection, and constructive editorial suggestions throughout the preparation of this book; without her support and love this book would not have been completed.
Behnam Kamali
Note
1.
IATA (International Air Transport Association) Fact Sheet Economic and Social Benefits of Air Transport, 2017.
Acronyms
A
AAA
Authentication, Authorization, and Accounting
A/A
Aircraft-to-Aircraft or Air-to-Air
AAS
Adaptive Array System
ABS
Advanced Base Station
ACARS
Aircraft Communications and Addressing Reporting System
ACAST
Advanced CNS Architectures and Systems Technologies
ACF
Area Control Facility
ACI
Adjacent Channel Interference
ACK
ARQ/HARQ positive acknowledgement
ACM
ATC Communications Management
ACP
Aeronautical Communications Panel
ACSP
Aeronautical Communication Service Provider
ADS
Automatic Dependent Surveillance
ADS-B
Automatic Dependent Surveillance-Broadcast
ADSL
Asymmetric Digital Subscriber Links
AeroMACS
Aeronautical Mobile Airport Communications System
AES
Advanced Encryption Standard
A/G
Air-to-Ground
AI
Aeronautical Information
AIP
Airport Improvement Program (Plan)
AIP
Aeronautical Information Publication
AIRMET
Airmen's Meteorological Information
AIS
Aeronautical Information Services
AM
Amplitude Modulation
AMC
Adaptive Modulation Coding
AMC
ATC Microphone Check
AMPS
Advanced Mobile Phone Services
AM(R)S
Aeronautical Mobile Route Services
AMS
Advanced Mobile Station
ANC
Air Navigation Conference
ANSP
Air Navigation Service Provider
AOC
Airline Operational Control
AP
Action Plan
APN
Airline Private Networks
APCO
Association of Public Safety Communications Officials-International
ARINC
Aeronautical Radio Incorporation
ARQ
Automatic Repeat Request
ARTCC
Air Route Traffic Control Center
ASA
Adjacent Subcarrier Allocation
ASA
Airport Surface Area
ASBU
Aviation System Block Upgrade
ASDE
Airport Surface Detection Equipment
ASN
Access Service Network
ASN-GW
Access Service Network Gateway
ASP
Application Service Provider
ASR
Airport Surveillance Radar
ASSC
Airport Surface Surveillance Capability
ATC
Air Traffic Control
ATCBI
Air Traffic Control Beacon Interrogator
ATCT
Air Traffic Control Tower
ATIS
Automatic Terminal Information Service
ATM
Air Traffic Management
ATN
Aeronautical Telecommunications Network
AWG
Aviation Working Group
AWGN
Additive White Gaussian Noise
B
BBC
British Broadcasting Company
BC
Boundary Coverage
BE
Best Effort
BER
Bit Error Rate
BFSK
Binary Frequency Shift Keying
BFWA
Broadband Fixed Wireless Applications
BGP
Border Gate Protocol
BPSK
Binary Phase Shift Keying
BR
Bandwidth Request
BS
Base Station
BSID
Base Station ID
BSN
Block Sequence Number
BTC
Block Turbo Code
BTS
Base Transceiver Station
B-VHF
Broadband VHF
BWA
Broadband Wireless Access
C
CC
Convolutional Code
CCI
Co-Channel Interference
CCM
Counter with Cipher-block chaining Message authentication code
CCRR
Co-Channel Reuse Ratio
CCTV
Close Circuit Television
CDM
Collaborative Decision Making
CDMA
Code Division Multiple Access
CE
Cyclic Extension
CFR
Code of Federal Regulation
CID
Connection Identifier
CINR
Carrier to Interference and Noise Ratio
CIR
Channel Impulse Response
CLCS
Cable Loop Communications Systems
CLE
Cleveland-Hopkins International Airport
CM
Context Management
CMAC
Cipher-based Message Authentication Code
CNR
Carrier-to-Noise Ratio
CNS
Communications, Navigation, and Surveillance
COCR
Communications Operating Concept and Requirements
COFDM
Coded Orthogonal Frequency Division Multiplexing
CO-MIMO
Cooperative MIMO
COST
European Cooperation for Scientific and Technical Research
COTS
Commercial Off of The Shelf
CP
Cyclic Prefix
CPDLC
Controller–Pilot Data Link Communications
CPE
Customer Premises Equipment
CPS
Common Part Sublayer
CQI
Channel Quality Indicator
CQICH
Channel Quality Indicator Channel
CRC
Cyclic Redundancy Check
CRD
Clearance Request and Delivery
CRSCC
Circular Recursive Systematic Convolutional Code
CS
Convergence Sublayer (Service Specific Convergence Layer)
CSA
Commercial Service Airports
C-SAP
Control-Service Access Point
CSI
Channel State Information
CSMA
Carrier Sense Multiple Access
CSN
Connectivity Service Network
CTC
Convolutional Turbo Code
CTF
Channel Transfer Function
CWG
Certification Working Group
D
DAB
Digital Audio Broadcasting
DAL
Design Assurance Levels
D-ATIS
Digital Automatic Terminal Information System
D-AUS
Data Link Aeronautical Update Service
DBFSK
Differential Binary Phase Shift Keying
DCL
Departure Clearance
DFF
D (Delay) Flip-Flop
D-FIS
Digital Flight Information Services
DFT
Discrete Fourier Transform
DHCP
Dynamic Host Configuration Protocol
DHS
Department of Homeland Security
DIUC
DL Interval Usage Code (DIUC)
D-LIGHTING
Active Runway Lighting Systems
DME
Distance Measuring Equipment
D-NOTAM
Digital Notice to Airmen
DOCSIS
Data Over Cable Service Interface Specification
DOC
Department of Commerce
DOD
Department of Defense
DOT
Departments of Transportation
D-OTIS
Downlink (DL) Operational Terminal Information Service
DPSK
Differential Phase Shift Keying
DRNP
Dynamic Required Navigation Performance
DRR
Deficit Round-Robin
D-RVR
Download Runway Visual Range
DSB
Double Side Band
DSB-TC
Double Sideband Transmitted Carrier
D-SIG
Digital (or DL) Surface Information Guidance
DSP
Digital Signal Processing
DSSS
Direct Sequence Spread Spectrum
D-TAXI
Data Link Taxi
4DTRAD
4-D Trajectory Data Link
D-WPDS
Data Link Weather Planning Decision Service
E
EAP
Extensible Authentication Protocol
ECC
Error Correction Coding
EDF
Earliest Deadline First
EDS
Evenly Distributed Subcarrier
EFB
Electronic Flight Bag
ERIP
Effective Isotropic Radiated Power
ertPS
Extended Real-Time Polling Services
ESMR
Enhanced Specialized Mobile Radio
EUROCAE
European Organization for Civil Aviation Equipment
EUROCONTROL
European Organization for the Safety of Air Navigation
F
FAA
Federal Aviation Administration
FAR
Federal Aviation Regulations
FBSS
Fast Base Station Switching
FCH
Frame Control Header
FCI
Future Communications Infrastructure
FCS
Future Communications Studies
FDD
Frequency Domain (Division) Duplexing
4DTRAD
4D Trajectory Data Link
FDM
Frequency Division Multiplexing
FDMA
Frequency Division Multiple Access
FEC
Forward Error Correction
FER
Frame Error Rate
FFR
Fractional Frequency Reuse
FFT
Fast Fourier Transform
FH
Frequency Hopping
FIFO
First-In-First-Out
FirstNet
First Responder Network Authority
FIS
Flight Information Services
FL
Forward Link
FM
Frequency Modulation
FMS
Flight Management System
FOM
Flight Operations Manual
FRF
Frequency Reuse Factor
FSS
Flight Service Stations
FTP
File Transfer Protocol
FUSC
Full Usage of Subchannels
FWA
Fixed Wireless Access
G
GA
General Aviation
G/A
Ground-to-Air
GANP
Global Air Navigation Plan
GF
Galois Field
G/G
Ground to Ground
GMH
Generic MAC Header
GoS
Grade of Service
GPS
Global Positioning System
GRE
Generic Routing Encapsulation
GRC
Glenn Research Center
GTG
Graphical Turbulence Guidance
H
HARQ
Hybrid Automatic Repeat reQuest
HDSL
High-bit-rate Digital Subscriber Links
HDTV
High Definition Television
HF
High Frequency
HFDD
Half Frequency Division Duplexing
HHO
Hard Handover
HMAC
Hash Message Authentication Code
HNSP
Home Network Service Provider
HO
Handover, Handoff
HTTP
Hypertext Transport Protocol
I
IAI
Inter-Application Interference
IAIP
Integrated Aeronautical Information Package
IATA
International Air Transport Association
ICAO
International Civil Aviation Organization
ICI
Inter Carrier Interference
ICIC
Inter-Cell Interference Coordination
IDFT
Inverse Discrete Fourier Transform
IDR
Inter Domain Routers
IEEE
The Institute of Electrical and Electronic Engineers
IER
Information Exchange and Reporting
IETF
Internet Engineering Task Force
IFFT
Inverse Fast Fourier Transform
IFR
Instrument Flight Rules
IMT
International Mobile Telecommunications
IP
Internet Protocols
IPS
Internet Protocol Suite
IPTV
Internet Protocol Television
IPv6
Internet Protocols Version 6
ISDN
Integrated Services Digital Network
ISG
Internet Service Gateway
ISI
Intersymbol Interference
ISL
Instrument Landing System
ISM
Industrial, Scientific, Medical
ITS
Intelligent Transportation System
ITT
International Telephone & Telegraph
ITU
International Telecommunication Union
ITU-R
International Telecommunication Union-Radiocommunication
J
JPDO
Joint Planning and Development Office
L
LAN
Local Area Network
LCR
Level Crossing Rate
LDL
L-band Data Link
LDPC
Low Density Parity Check
LEO
Low Earth Orbit
LMR
Land Mobile Radio
LOS
Line of Sight
LOS-O
LOS-Open
LSB
Least Significant Bit
LTE
Long Term Evolution
M
MAN
Metropolitan Area Network
MAP
Media Access Protocol
MASPS
Minimum Aviation System Performance Standards
MBR
Maximum Burst Rate
MBS
Multicast-Broadcast Service
MCBCS
Multicast and Broadcast Services
MCM
Multicarrier Modulation
MDHO
Micro Diversity Handover
MET
Meteorological Data
METARS
Meteorological Aerodrome Reports
MFD
Multifunction Display
MIMO
Multiple-Input-Multiple-Output
ML
Maximum Likelihood
MLS
Microwave Landing System
MLT
Maximum Latency Tolerance
MMR
Mobile Multihop Relay
MODEM
Modulation/Demodulation
MOPS
Minimum Operational Performance Standards
MPC
Multipath Component
MPSK
M-ary Phase Shift Keying
MR-BS
Multihop Relay-Base Station
MRS
Minimum Receiver Sensitivity
MRTR
Minimum Reserved Traffic Rate
MS
Mobile Station
M-SAP
Management-Service Access Point
MSB
Most Significant Bit
MSC
Mobile Switching Center
MSP
Master-Slave Protocol
MSS
Mobile Satellite Service
MSTR
Maximum Sustained Traffic Rate
MTSO
Mobile Telephone Switching Office
MU-MIMO
Multiple User MIMO
N
NACK
Negative ARQ/HARQ Acknowledgement
NAP
Network Access Provider
NAS
National Airspace System
NASA
National Aeronautics and Space Administration
NASP
National Airport System Plan
NAVAID
Navigation Aids
NCMS
Network Control and Management System
NextGen
Next Generation Air Transportation System
NLOS
None Line of Sight
NLOS-S
NLOS-Specular
NNEW
Network Enabled Weather
NOTAM
Notice to Airman
NPIAS
National Plan of Integrated Airport Systems
NRM
Network Reference Model
nrtPS
Non-Real-Time Polling Services
NRT-VR
Non-Real-Time Variable Rate
NSNRCC
Non-Systematic Non-Recursive Convolutional Code
NSP
Network Service Provider
NTIA
National Telecommunications and Information Administration
NTIS
National Traffic Information Service
NWG
Network Working Group
O
OCL
Oceanic Clearance Delivery
OFDM
Orthogonal Frequency Division Multiplexing
OFDMA
Orthogonal Frequency Division Multiple Access
OFUSC
Optional FUSC
OOOI
Out, Off, On, In (time)
OPUSC
Optional PUSC
OSI
Open System Interconnection
OTIS
Operational Traffic Information System
P
PAPR
Peak-to-Average Power Ratio
PBN
Performance Based Navigation
PCS
Personal Communications Systems
PDC
Pre-Departure Clearance
Probability Density Function
PDP
Power Delay Profile
PDU
Protocol Data Unit
PDV
Packet Delay Variation
PIB
Pre-flight Information Bulletins
PKM
Privacy Key Management
PKMv2
Privacy Key Management version 2
PMDR
Private Mobile Digital Radio
PMP
Point-to-Multipoint
PMR
Private/Professional Mobile Radio
PN
Pseudo Noise
PS
Public Safety
PSC
Public Safety Communications
PSD
Power Spectral Density
PSTN
Public Switched Telephone (Telecommunications) Networks
PUSC
Partial Usage of Subchannels
Q
QAM
Quadrature Amplitude Modulation
QoC
Quality of Communication
QoS
Quality of Service
QPSK
Quadrature Phase Shift Keying
R
RADIUS
Remote Authentication Dial-In User Service
RARA
Rate Adaptive Resource Allocation
R&O
Report and Order
RCPC
Rate Compatible Punctured Convolutional Code
RCF
Remote Communications Facility
RDS
Randomly Distributed Subcarrier
RFI
Radio Frequency Interference
RL
Reverse Link
R-MAC
Relay Media Access Control
RMM
Remote Maintenance and Monitoring
RMS-DS
Root-Mean Square Delay Spread
RP
Reference Point
RR
Round-Robin
RRA
Radio Resource Agent
RRC
Radio Resource Controller
RRM
Radio Resource Management
RS
Relay Station
RS
Reed Solomon
RSS
Received Signal Strength
RSSI
Received Signal Strength Indicator
RTCA
Radio Technical Commission for Aeronautics
RTG
Receive Time Gap
rtPS
Real-Time Polling Services
RTR
Remote Transmitter Receiver
RT-VR
Real-Time Variable Rate
RVR
Runway Visual Range
R
x
Receiver
S
SA
Security Association
SANDRA
Seamless Aeronautical Networking Through Integration of Data Links, Radios, and Antennas
SAP
Service Access Point
SARPS
Standards and Recommended Practices
SAS
Smart Antenna System
SBS
Surveillance Broadcast System
SBS
Serving Base Station
SC
Single Carrier
SC
Special Committee
SD
Stationarity Distance
SDU
Service Data Unit
SESAR
European Commission Single European Sky ATM Research
SF
Service Flow
SFID
Service Flow Identifier
SHO
Soft Handover
SIGMET
Significant Meteorological Information
SIM
Subscriber Identify Module
SINR
Signal-to-Interference-Plus-Noise Ratio
SIP
Session Initiation Protocol
SIR
Signal to Co-Channel Interference Ratio
SISO
Single-Input Single-Output
SLA
Service Level Agreements
SMR
Specialized Mobile Radio
SNR
Signal-to-Noise Ratio
SOFDMA
Scalable Orthogonal Frequency Division Multiple Access
SONET
Synchronous Optical Network
SPWG
Service Provider Working Group
SS
Stationary (Subscriber) Station
STBC
Space-Time Block Code
STC
Time Space Coding
Std.
Standard
STDMA
Self-Organized Time Division Multiple Access
STTC
Space-Time Trellis Code
STTD
Space-Time Transmit Diversity
SU-MIMO
Single User MIMO
SWIM
System Wide Information Management
T
TBCC
Tail Biting Convolution Codes
TBS
Target Base Station
T-CID
Tunneling Connection Identifier
TCM
Trellis Coded Modulation
TCP
Transmission Control Protocol
TDD
Time Division (Domain) Duplexing
TDL
Tapped-Delay Line
TDLS
Tower Data Link System
TDM
Time Division Multiplexing
TDMA
Time Division Multiple Access
TDLS
Tower Data Link System
TETRA
Terrestrial Trunk Radio
3GPP
Third Generation Partnership Project
TIA
Telecommunications Industry Association
TLV
Type, Length, Value
TO
Transmission Opportunities
ToR
Terms of References
TR
Transmitter Receiver
TRACON
Terminal Radar Approach Control
TSO
Technical Standard Orders
TTG
Transmit Time Gap
TUSC1
Tile Usage of Subchannels 1
TUSC2
Tile Usage of Subcarrier 2
TWG
Technical Working Group
Tx
Transmitter
U
UA (
γ
)
Percentage of Useful Area Coverage when Receiver Sensitivity is
γ
dB
UAT
Universal Access Transceiver
UCA
Useful Coverage Area
UGS
Unsolicited Grant Services
UISC
UL Interval Usage Code
US
Uncorrelated Scattering
USAS
User Applications and Services Survey
USIM
Universal Subscriber Identify Module
UWB
Ultrawideband
V
VDL
VHF Data Link
VHF
Very High Frequency
VLSI
Very Large-Scale Integration
VNSP
Visited Network Service Provider
VoIP
Voice over Internet Protocols
VOLMET
French acronym of VOL (flight) and METEO (weather)
W
WAAS
Wide Area Augmentation System
WDM
Wavelength Division Multiplexing
WFQ
Weighted Fair Queue
Wi-Fi
Wireless Fidelity
WiMAX
Worldwide Interoperability for Microwave Access
WMAN
Wireless Metropolitan Area Network
WRC
World Radiocommunication Conference
WSS
Wide-Sense Stationarity
WSSUS
Wide Sense Stationary Uncorrelated Scattering
WWAN
Wireless Wide Area Network
WXGRAPH
Graphical weather information
1Airport Communications from Analog AM to AeroMACS
1.1 Introduction
The safety of air travel and air operations is critically linked to the availability of reliable aeronautical communications and navigation systems. Owing to the fact that flight safety is the highest priority in aviation, extreme measures must be taken to protect the aeronautical communication systems against harmful interference, malfunction, and capacity limitation.
In the early days of commercial aviation in the 1940s, analog double-sideband transmitted-carrier (DSB-TC) amplitude modulation (AM) over VHF band was adopted for aeronautical radio. This selection was made mostly for the reason that analog AM was the only fully developed and proven radio communications technology at the time. The number of VHF radio channels increased over the decades subsequent to the end of the World War II. In the 1980s, the VHF band of 118–137 MHz was allocated to aeronautical radio. With channel spacing of 25 kHz, 760 VHF AM (25-AM) radio channels became available. During the same decade, the avionics community predicted that early in the next century growth in flight operations and air traffic volume would demand communication capacity 1 that would be well beyond what was available in those days.
The air-to-ground (A/G) and ground-to-air (G/A) VHF communications system for civil air traffic control consisted of AM voice networks, where each flight domain had its own dedicated network. These networks were not interconnected and actually operated independently; however, their architecture was roughly the same. The pilot-to-control tower (uplink; UL, also known as reverse channel or reverse link; RL) and controller-to-pilot (downlink, DL also called forward channel or forward link, FL) radio voice links were half-duplex connections and operated on a “push-to-talk” basis. Backup radio channels were provided in the event of system malfunction, power failure, or other unexpected situations. The VHF radio equipment was digitally controlled with the total of 760 channels, of which 524 channels were dedicated to A/G and G/A communications for air traffic control (ATC) purposes. The remaining channels were used by airlines for airline operational control (AOC). The AOC predominantly used and still uses a data service called the aircraft communications and address reporting system (ACARS) to manage and track the aircraft. However, the radio link can also be used for voice communications between pilots and airline agents [1]. Currently, the bulk of ground-to-ground (G/G) communications on the surface of airports is supported by wired and guided transmission systems, primarily through buried copper and fiber-optic cable loops. The G/G communications is also supported by a number of wireless systems, among them are VHF AM radio, airport WiFi system, and even some airport radar facilities.
In addition to the allocated VHF spectrum, two other spectral bands were considered to become available for aviation on a shared basis with other applications. First is an L-band spectrum of 960–1024 MHz, originally allocated for distance measuring equipment (DME). The second one is a C-band spectrum over 5000–5150 MHz, traditionally earmarked for microwave landing system (MLS). This radio spectrum was later allocated as the frequency band to carry aeronautical mobile airport communications system (AeroMACS ). AeroMACS technology is the main focus of this text and at the time of its preparation, AeroMACS was already standardized and globally harmonized as a broadband IP data communication link for safety and regularity of flight at the airport surface. Currently, AeroMACS is being tested over several major U.S. airports and, barring any unforeseen complications, it is expected to be deployed globally by the year 2020. For future airports, AeroMACS is envisioned to constitute the backbone of the communications system for the airport surface, whereas older airports can form a communications infrastructure in which AeroMACS is complimented with the airport fiber optic and cable loops that are already in place.
1.2 Conventional Aeronautical Communication Domains (Flight Domains)
Aeronautical signals pass through several wireless communication channels before they reach the destination. Four possible transmission links exist in aeronautical communications path: aircraft (air)-to-controller (ground), A/G; controller-to-aircraft, G/A; ground-to-ground, G/G, and aircraft-to-aircraft; A/A links. The aircraft continuously communicates with the NAS (National Airspace System), or the global airspace system, throughout the flight duration. There are several different domains (channels) through which the aircraft may be required to communicate with a ground station. Each one is a wireless channel with its own particular conditions, constraints, and characteristics. For an overall aeronautical communications system design or simulation, each of the channels listed below must be considered and characterized.
Enroute Communication Channel:
This is the domain when the aircraft is airborne and A/G and G/A transmissions are required. This is essentially a high-speed mobile communication link in which the aircraft flying is at high altitude and close to its maximum speed. This link can be modeled as a simple double-ray wireless channel, or a Rayleigh fading channel. However, in the majority of cases the channel contains a line-of-sight (LOS) path and a ground reflection. When the aircraft elevation angle is high the ground reflection takes place at a point very close to the ground station, therefore, the path length between the two rays is very small and hence they cannot be resolved by the receiver [2].
Flying Over a Ground Station:
This is a special case of enroute channel during which the Doppler effect changes its sign. For design and simulation of the aeronautical communications links, this mode must be considered separately from the enroute case [3].
Landing and Takeoff Domain:
The aircraft is airborne at low altitudes and moving at its landing and takeoff speed, it is engaged in A/G and G/A communications and is close to the control tower. The channel is multipath with a strong LOS component.
Surface (Taxiing) Channel:
In this domain the aircraft moves rather slowly toward or away from the terminal, it is therefore a low-speed low-range mobile communications affected by multipath and some Doppler effect.
Parking Mode:
This mode is applicable when the aircraft is on the ground and close to a terminal and traveling at a very low speed or is parked. This requires essentially a stationary wireless transmission of low range.
Air
-
to-Air:
This channel is used for the purpose of communications between two aircraft while they are in flight.
Oceanic Domain:
This channel has its own characteristics in the sense that it is a long-range communications channel for the most parts. VHF LOS transmission is not feasible for this domain.
Polar Domain:
This is also a channel in which long-range communications take place. This domain has a limited satellite access.
In some literature, communications in domain 3 is referred to as terminal communications. Communications over domains 3–5 together are what is referred to as airport surface communication in this chapter. For oceanic and remote areas, such as polar regions, since LOS transmission to ground stations is not possible, HF (high frequency) band and satellite systems are used.
1.3 VHF Spectrum Depletion
It was long accepted that as a rule of thumb, and baring any unexpected sudden traffic increase, the aviation traffic is anticipated to have an annual growth of at least 2%. However, the spectrum that was allocated for various functionalities of aerospace management system remained fixed, except for the abovementioned L-band and C-band that later became available on a spectrum sharing basis. The safety, security, growth, and efficient operation of national and global aviation systems are vitally dependent on reliable communications, navigation, and surveillance (CNS) services. Communications provides wireless and wireline connections for voice and data exchange between various entities involved in the aviation system, that is, aircraft, airports, terminals, runways, control towers, satellite transponders, and so on. The other essential component of aviation system is the air traffic management (ATM) system that heavily relies on communications and surveillance components of CNS [4].
In the late 1990s, the demand for aeronautical communications links surpassed what the existing VHF radio channels could supply without unacceptable level of interference. In the United States, rapid increase in air traffic due to commercial transportation and general aviation (GA) (private aircrafts) was the culprit. In Europe, owing to an almost exponential growth in commercial flights in the 1990s, the problem was more severe. Besides, many major European airports with large volume of air traffic are located at close geographical proximity of each other. In the early 2000s, the Europeans proposed a scheme in which 25 kHz spacing band is reduced to 8.33 kHz and thereby the number of available radio channels is tripled to 2280. This scheme that became known as “8.33-AM” ran into some standardization problems and was not implemented in the United States although it was accepted and deployed in Europe.
As the capacity of VHF aeronautical radio was reaching saturation in the United States and in Europe, the International Civil Aviation Organization 2 (ICAO) at its 11th Air Navigation Conference held in September 2003 made a number of recommendations. One recommendation specifically called for exploration of new terrestrial and satellite-based technologies on the basis of their potential for standardization for aeronautical mobile communications use. A second recommendation asked for monitoring emerging communications technologies but undertaking standardization work only when the technologies can meet current and emerging ICAO ATM requirements. These requirements asked for technologies that are technically proven, meet the safety standards of aviation, are cost-effective, can be implemented without prejudice to global harmonization, and are consistent with Global Air Navigation Plan (GANP) for CNS/ATM.
The key functional objective for future aeronautical communications systems was deemed to provide relief to the congested VHF aeronautical band by either substantially increasing the number of voice channels or using the spectrum more efficiently or a combination thereof. In doing so, one could contemplate several options. A direct possibility was using the available VHF band more efficiently by introducing new communication technologies that save spectrum. The other option was utilizing the available VHF spectrum more efficiently by reducing the channel spacing and guard bands. Another approach was incorporating data communications links such that the majority of required voice messages can be transmitted more efficiently by data and text messages. Yet, another alternative was to take advantage of appropriate frequencies outside of the aeronautical VHF band that were available on a shared spectrum basis. One could also contemplate applying technologies such as GPS and other satellite-based technologies that have their own allocated spectrum and are suitable for carrying some components of aeronautical communications [4].
1.4 The ACAST Project
In 2003, NASA initiated an R&D project for future CNS/ATM infrastructure that was termed as “Advanced CNS Architectures and Systems Technologies”; ACAST. The main objective of the ACAST project was to define a transitional architecture to support the transformation of the present day patched-together CNS infrastructure into an integrated high-performance digital network-centric system. This was to take place, perhaps, through technologies that can be implemented in near-term and midterm to address the airspace urgent needs, while they can simultaneously be a part of the long-term solution. It was suggested that one long-term solution that is most cost-effective and can support present and potential future requirements is a network-oriented hybrid of satellite and ground-based communication systems. It was further recommended that all ATM and nonpassenger enroute communications be handled by the satellite-based technology, and all terminal and surface communications be placed on the ground-based system [6]. The ATM communications consists of several components: ATC that includes CPDLC (controller–pilot data link communications) – a method by which control tower can communicate with pilots via data and text (to be discussed in Section 1.5.4)-, automatic dependent surveillance (ADS), National Traffic Information Service (NTIS), AOC, and advisory service; such as flight information services (FIS) and weather sensor data downlink.
There were 10 partially overlapping subprojects envisioned in the ACAST project. The first three subprojects were considered foundation or “guiding frameworks” for other technology development in the ACAST project. The first was Transitional CNS Architecture philosophy in which the key requirements for CNS transitional architecture were increased integration of data transmission, full A/G network connectivity, high capacity, global coverage, efficient use of spectrum, and capability to evolve into a long-term CNS architecture. The second subproject was Global A/G Network. This formed the backbone of the CNS infrastructure. The major feature of this network was full CNS information sharing with all network users. The required protocols that were gradually emerging indicated that the Internet techniques are likely to be applied in A/G network as well. The third subproject was related to Spectrum Research. There was and is an ever-increasing demand for spectrum for aviation, thus efficient usage of the spectrum and development of new CNS technologies that would use the available spectrum to meet the future needs of aeronautical applications was deemed to be a key component of the ACAST project.
Another ACAST subproject was “VHF systems Optimization.” This subproject investigated the methods and techniques that optimize the performance of the then VHF aeronautical band [6].
In meeting the key functional objectives of VHF aeronautical communications, one should not lose the sight of the strategic objectives of the global airspace system; that the change must be cost justified, it should be globally applicable and interoperable, and it should allow a smooth transition for service providers and users, and should avoid needless avionics [7]. In providing short-term or midterm resolution to congestion problems, it would be prudent and desirable to ensure that the technology under consideration has the potential of becoming a part of the long-term solution, and is able to furnish a smooth transition from present to near-term and to long-term aeronautical communication system.
1.5 Early Digital Communication Technologies for Aeronautics
For over three decades, analog VHF DSB-AM system represented the dominant radio technology for aeronautics. In the late 1970s and early 1980s, data communications techniques gradually permeated into aeronautical information exchange systems; following the general trend in the then telecommunications industry, morphing into computer communication era. In this section, pre-AeroMACS digital communications schemes applied and implemented for aeronautics, as well as technologies that were considered for this application but were never implemented, are briefly reviewed in a historical context.
