Recent Developments in Aircraft Wireless Networks 1 of 13 file X www docs cse574 06 ftp aircraft wireless index html Recent Developments in Aircraft Wireless Networks Obi Orjih oco1 cec wustl edu Abstract This report discusses some key recent developments in the area of wireless networking on aircraft We discuss the products and services in commercial aviation that have been driven by the demand for in flight entertainment and connectivity We also touch on the research that has enabled this technology Lastly we mention the developments in military aircraft wireless networks and the standards behind them See also Table of Contents 1 Introduction 2 Research Developments 2 1 Integration and Interoperability 2 2 Interference 2 3 Mobility 2 4 Quality of Service 3 Commercial Developments 3 1 Satellite Services 3 2 Airline Services 4 Military Developments 4 1 Link 16 4 2 JTRS 5 Summary 6 References 7 List of Acronyms 1 Introduction In recent years wireless networking has become more commonplace than wired networking One application domain in which wireless networks are of far greater practical use is aviation since planes are scattered all over the world In this paper we discuss recent and future developments in aircraft wireless networks AWNs In commercial aviation the major goals is to provide in flight Internet connectivity to passengers We discuss some research which has enabled this technology as well as some current and future services such as Connexion by Boeing and OnAir which satisfy this demand The military uses wireless networks to improve tactical situational awareness for war fighting aircraft It is important to note that the AWN paradigm is different in military applications where the intent is not to connect to the public Internet The military domain is also where the development of AWNs is the most mature in terms of standardization and ubiquity We discuss two of the most relevant military AWN standards Link 16 and JTRS Back to Table of Contents 5 9 2006 7 36 PM Recent Developments in Aircraft Wireless Networks 2 of 13 file X www docs cse574 06 ftp aircraft wireless index html 2 Research Developments In this section we discuss research work dealing with AWNs Since the motivation for the work in this area is support of in flight passenger communication our focus is on research concerning network connectivity from within an aircraft to the outside world A common architecture for these services found in research and industry is shown in Figure 1 It consists of three basic segments an aircraft a satellite link and a ground station On the aircraft a wireless access point can be used to provide connectivity to passengers and crew members The satellite link provides a connection to the ground station which is connected to the Internet Figure 1 Example commercial airline network topology A common thread among the research projects examined here is that each aims find a way to enable AWNs to be more useful and efficient In fact some of the research and development work eventually had useful application in industry The major issues in AWN research that we examine are interoperability interference mobility and quality of service QoS Interoperability is important because airlines are looking to provide different services to their passengers which requires the use of multiple different technologies Two of the key services considered are Internet and cellular connectivity To provide these services an aircraft must have access points for receiving both kinds of wireless signals and be able to transmit traffic from both systems to the ground via the satellite link Interference comes into play because it is undesirable for these transmissions to interfere with the navigational and communications systems needed for operation of the aircraft Case studies have shown that there have been times where passenger personal electronic devices PEDs have caused aircraft systems to malfunction However some research studies indicate that this should not be the case The physical movement of the aircraft makes mobility and QoS issues of concern An aircraft and the ground stations with which it communicates must be mobility aware as the aircraft is essentially a moving network As it moves an aircraft must register with each new ground station it encounters in order to establish a path for traffic to and from the aircraft The ground station must also handle routing to the multiple nodes which reside on each aircraft connected to it The process of switching between satellites and or ground stations can cause a 5 9 2006 7 36 PM Recent Developments in Aircraft Wireless Networks 3 of 13 file X www docs cse574 06 ftp aircraft wireless index html loss or degradation of service for passengers The architecture of the communication system should be such that the impact of handovers on QoS is minimized We examine research dealing with these issues in the following subsections 2 1 Integration and Interoperability One research project developed to demonstrate interoperability in AWNs was the Terrestrial Hybrid Environment for Verification of Aeronautical Networks THEVAN As the name suggests the platform was not actually an aircraft but a modified ambulance chassis loaded with racks of wireless networking equipment The intent was to demonstrate the integration of different technologies which could be used to provide network services in an aircraft These technologies included a Ku band satellite system a medium data rate satellite system MDSS a commercial Very High Frequency VHF radio and IEEE 802 11b The Ku satcom phased array antenna was used to provide a full duplex 2 Mbps 256 kpbs downlink uplink connection to a fixed ground station via satellite The MDSS was composed of 16 L band Globalstar compatible satellite phones providing an aggregate data rate of 112 kbps The VHF data radios were commercial modems which provided a 19 2 kbps full duplex link Cisco 802 11b 11 Mbps access points were used with external bi directional amplifiers and omni directional antennas The testbed was used to evaluate IP based Mobile IPv4 and IPv6 connections on a mobile platform They demonstrated that TCP and UDP connections could be maintained as the platform moved through a wide area They also showed that the different networking technologies could be integrated to provide Internet services such as Hyper Text Transfer Protocol HTTP and File Transfer Protocol FTP to users THEVAN was also able to switch between the different forms of
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