Seminer report aeronautical_communication

Aeronautical Communication
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AERONAUTICAL COMMUNICATION
SEMINAR REPORT
Submitted by
Subhajit Ghosh
Semester: 6th
Department:ComputerScience & Engineering
Roll No.: 16900113106
In partial fulfilment for the award of the degree of
BACHELOR OF TECHNOLOGY
in
COMPUTER SCIENCE & ENGINEERING
Academy of Technology
Adeconagar, Hoogly – 712121
2015

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ACKNOWLEDGEMENT
The background of this work has been supported by Prof. Sudipta Roy, my fellow co-mates and
nonetheless by the internet resources for excavating through the complete analysis of the report. I
heartily thank all those who have been kind and delivered their immense patience throughout the
work of the complete analysis.
Subhajit Ghosh (roll no. - 106)

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ABSTRACT
The uprising demand for making air travel more secured, pleasant and productive for the passengers
is one of the winning factors for the airlines and aircraft industry. The modern scenario targets to
achieve a higher data rate communication services, preferably internet applications. Since people
are becoming more and more used to their own communications equipment, such as mobile phones
and laptops with Internet connection, either through a network interface card or dial-in access
through modems, business travellers will soon be demanding wireless access to communication
services. Thus, aeronautical communication meets a challenging scenario due to the ever increasing
data rate requirements of applications.
The project will provide UMTS services, IEEE 802.11 and Bluetooth to the cabin passengers. This
paper will thus describe a methodology for the planning of such system. In the future, airliners will
provide a variety of entertainment and communications equipment to the passenger.

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TABLE OF CONTENTS
1. Abstract ----------------------------------------- 3
2. Introduction ----------------------------------- 6
3. Wireless Cabin Architecture ----------------- 7
3.1 The architecture --------------------------- 7
4. Satellite Connection --------------------------- 9
4.1 General architecture ---------------------- 9
5. Technical Overview --------------------------- 11
5.1 UMTS -------------------------------------- 11
5.2 Bluetooth ----------------------------------- 12
5.3 IEEE 802.11 (LANs) --------------------- 14
6. Interference ------------------------------------- 15
7. Service Integrator ------------------------------ 16
8. Service Dimensioning ------------------------ 17
9. CMHN ------------------------------------------- 18
10.Conclusion --------------------------------------- 19

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LIST OF TABLES AND FIGURES
1. The wireless functional architecture (figure2.1) -------------------------------------- 7
2. Satellite system for aeronautical communication architecture(figure 3.1) ------ 10
3. UMTS network architecture(figure 4.1) ---------------------------------------------- 12
4. State diagram of link layer state machine(figure 4.2) ------------------------------- 13
5. Schematic diagram of Service Integrator (figure6.1) ------------------------------- 16
6. CMHN model (figure 8.1) -------------------------------------------------------------- 19

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1. INTRODUCTION
Aeronautical communication refers to the communication between two or more aircrafts or the
ground members. The ever increasing demand for making an air journey more pleasant, secured
and comfortable has made the airlines and the aircraft industry to surge with higher profit rates and
has been a part of their winning factor. As safety is the primary focus, thus communication via
wireless methods is an effective way to communicate from aircraft to the personnel. Global
coverage has become essential in order to follow a continuous service. Therefore, satellite
communication has become indispensable, and together with the ever increasing data rate
requirements for applications, satellite communication meets an expansive market. Wireless Cabin
(IST -2001-37466) is looking into those radio access technologies to be transported via satellite to
terrestrial backbones. To properly deploy state-of-the-art satellite technologies, several challenges
pertaining to provisioning an end-to-end Quality of Service (QoS) and mobility have to be
addressed. The project will provide UMTS services, W-LAN IEEE 802.11b and Blue tooth to the
cabin passengers. With the advent of new services a detailed investigation of the expected traffic
is necessary in order to plan the needed capacities to fulfil the QoS demands. This paper will thus
describe a methodology for the planning of such system.
In the future, airliners will provide a variety of entertainment and communications equipment to
the passenger. Since people are becoming more and more used to their own communications
equipment, such as mobile phones and laptops with Internet connection, either through a network
interface card or dial-in access through modems, business travellers will soon be demanding
wireless access to communication services

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2. WIRELESS CABIN ARCHITECTURE
Aircraft cabin comprises of several different network technologies. Different subsystems have
different needs from the network infrastructure. While in-flight entertainment systems can work
with best effort delivery to transmit media content. Time triggered protocols are desirable for
equipment such as cabin audio that usually are high fidelity systems carrying uncompressed audio
data. Towards a wireless cabin: In-flight entertainment systems are gearing up to wireless content
distribution and many airlines have already begun to deploy them, eliminating a myriad of data
cabling, network switches and wiring. Aircrafts of the future are likely to sport a wireless network
infrastructure for various cabin functions such as the passenger service unit functions, cabin
lighting etc. In addition to the advantages of savings in wiring and maintenance costs and overall
weight reductions resulting in fuel savings, cabin re-configurations will become simpler.
2.1 THE ARCHITECTURE
The Wireless Cabin architecture consists of three segments, the Cabin Segment, the Transport
Segment and the Ground Segment. As depicted in Figure 2.1, the Cabin Segment consists of a Local
Access domain and a Service Integration domain.
Figure 2.1 The wireless functional architecture
The Local Access domain combines the UTRAN/GSM radio access segment, the WLAN access
segment and the Bluetooth access segment. The Service Integration domain hosts some core network

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functionalities of the UMTS network and IP protocol functions for authentication, admission control
and accounting, mobility support, Quality of Service (QoS) support and the interfaces towards the
satellite transport network. The key element of the Service Integration domain is a versatile router
with supporting protocol functions. The architecture is designed to enable the following main goals:
• Airlines can choose different features depending on aircraft type, e.g., basic communication
services for small A/C, enhanced communication services with onboard content for long range A/C,
wireless and secure crew communications.
• The system is independent of the satellite transport network; the airlines can choose satellite
service operators.
• Several satellite segments can be supported depending on the flight route.
• The satellite segment can vary upon the aircraft WirelessCabin capabilities (e.g., required bit
rate).
• Aircom service providers can support several satellite segments.
• The ground segment architecture supports several roaming principles (aircom provider as
roaming provider, terrestrial network operators as legacy network providers).
• Several charging possibilities and business chains are supported.

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3. SATELLITE CONNECTION
Aeronautical Communications Systems must be reliable and efficient. Connection to Aeronautical
networks is considered to be achieved by satellites with large coverage areas especially over
oceanic regions during long-haul flights. Currently, few geostationary satellites such as the
Inmarsat fleet are available for two-way communications that cover the land masses and the oceans.
Ku-band may be used on a secondary allocation basis for Aeronautical Mobile Satellite services
(AMSS) but bandwidth is scarce and coverage is mostly provided over continents.
3.1 GENERAL ARCHITECTURE
The general architecture of a satellite system for providing aeronautical communication services is
discussed in succeeding paragraphs.
3.1.1 Ground Segments: A typical satellite communication system is divided into three different
segments. These are respectively the ground, space and user segments. The ground segment is
responsible for interfacing the satellite communication system with the rest of the communication
network infrastructure to which the satellite system constitutes an access network. In the ground
segment of a satellite communication system, the information stream that arrives through the
ground infrastructure is adapted in order to be sent out on the air interface of the satellite network
gateway which in aeronautical communication systems is known as a Ground Earth Station (GES).
3.1.2 Space Segments: The space segment is composed of the satellite itself. The role of the space
segment is to either serve as a transparent reflector for the signals sent from the ground or to receive
process and re-generate a signal towards the ground in which case the satellite is called
regenerative.
3.1.3 User Segments: The user segment as its name indicates is where the users of the satellite
communication system are located. In the case of an Aeronautical Communication Satellite
System, the user segment is known as the Aeronautical Earth Station (AES).

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Figure 3.1 Satellite system for aeronautical communication architecture

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4. TECHNICAL OVERVIEW
4.1 UMTS
The Universal Mobile Telecommunication System (UMTS) is the third generation mobile
communications system being developed within the IMT-2000 framework. UMTS will build
on and extend the capability of today’s mobile technologies (like digital cellular and cordless)
by providing increased capacity, data capability and a far greater range of services.
UMTS supports maximum theoretical data transfer rates of 42 Mbit/s when Evolved HSPA
(HSPA+) is implemented in the network. Users in deployed networks can expect a transfer rate
of up to 384 kbit/s. Since 2006, UMTS networks in many countries have been or are in the
process of being upgraded with High-Speed Downlink Packet Access (HSDPA), sometimes
known as 3.5G. Currently, HSDPA enables downlink transfer speeds of up to 21 Mbit/s. Work
is also progressing on improving the uplink transfer speed with the High-Speed Uplink Packet
Access (HSUPA). Longer term, the 3GPP Long Term Evolution (LTE) project plans to move
UMTS to 4G speeds of 100 Mbit/s down and 50 Mbit/s up, using a next generation air interface
technology based upon orthogonal frequency-division multiplexing. The two existent
duplexing schemes for UMTS: UMTS–FDD and UMTS–TDD. UMTS–FDD relies on
wideband–CDMA (W–CDMA) access technique, while UMTS–TDD uses the TD-CDMA
access technique, a combination of CDMA and TDMA technologies. UMTS uses the same core
network standard as GSM/EDGE. This allows a simple migration for existing GSM operators.
However, the migration path to UMTS is still costly: while much of the core infrastructure is
shared with GSM, the cost of obtaining new spectrum licenses and overlaying UMTS at
existing towers is high.
CN can be connected to various backbone networks, such as the Internet or an Integrated
Services Digital Network (ISDN) telephone network. UMTS (and GERAN) include the three
lowest layers of OSI model. The network layer (OSI 3) includes the Radio Resource
Management protocol (RRM) that manages the bearer channels between the mobile terminals
and the fixed network, including the handovers.

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Figure 4.1 UMTS network architecture
4.2 BLUETOOTH
Bluetooth is a wireless technology standard for exchanging data over short distances (using short-
wavelength Ultra High Frequency radio waves in the ISM band from 2.4 to 2.485 GHz) from fixed
and mobile devices, and building personal area networks (PANs). The IEEE standardized
Bluetooth as IEEE 802.15.1, but no longer maintains the standard. Bluetooth divides transmitted
data into packets, and transmits each packet on one of 79 designated Bluetooth channels. Each
channel has a bandwidth of 1 MHz. It usually performs 800 hops per second, with Adaptive
Frequency-Hopping (AFH) enabled. Bluetooth low energy uses 2 MHz spacing, which
accommodates 40 channels. While each implementation has specific requirements that are detailed
in the Bluetooth specification, the Bluetooth core system architecture has many consistent
elements. The system includes an RF transceiver, baseband and protocol stacks that enable devices
to connect and exchange a variety of classes of data. The lowest three system layers — the radio,
link control and link manager protocols — are often grouped into a subsystem known as the
Bluetooth controller. This is a common implementation that uses an optional standard interface —
the Host to Controller Interface (HCI) — that enables two-way communication with the remainder
of the Bluetooth system, called the Bluetooth host.

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4.2.1 State Machine
The operation of the Link Layer can be described in terms of a state machine with the following
five states:
 Standby State
 Advertising State
 Scanning State
 Initiating State
 Connection State
Figure 4.2 State diagram of the link layer state machine
A master Bluetooth device can communicate with a maximum of seven devices in a piconet (an
ad-hoc computer network using Bluetooth technology), though not all devices reach this maximum.
The devices can switch roles, by agreement, and the slave can become the master (for example, a

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headset initiating a connection to a phone necessarily begins as master—as initiator of the
connection—but may subsequently operate as slave).
4.3 IEEE 802.11 (WIRELESSLAN STANDARDS)
802.11 and 802.11x refers to a family of specifications developed by the IEEE for wireless LAN
(WLAN) technology. 802.11 specifies an over-the-air interface between a wireless client and a
base station or between two wireless clients. The 802.11 family consists of a series of half-
duplex over-the-air modulation techniques that use the same basic protocol. 802.11-1997 was the
first wireless networking standard in the family, but 802.11b was the first widely accepted one,
followed by 802.11a, 802.11g, 802.11n, and 802.11ac. Other standards in the family (c–f, h, j) are
service amendments that are used to extend the current scope of the existing standard, which may
also include corrections to a previous specification. Wireless LAN networks operate using radio
frequency (RF) technology, a frequency within the electromagnetic spectrum associated with radio
wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created
that then is able to propagate through space.
A WLAN cell is formed by an AP and an undefined number of users in a range from approximately
20 to more than 300 m ( 100 m. in indoor environments) that access the AP through network
adapters (NAs ), which are available as a PC card that is installed in a mobile computer.

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5. INTERFERENCE
Once the above described measurements finish. four types of interferences within the CMHN have
to be studied: the co-channel interference among the terminals of the same wireless access segment,
the inter- segment interference between terminals of different wireless networks, the cumulative
interference of all simultaneous active terminals with the aircraft avionics equipment and the
interference of the CMHN into terrestrial networks.
From the co-channel interference analysis the re-use distance and the re-use frequency factor for
in-cabin topology planning will be derived. For this reason it is important to consider different AP
locations during the measurements.
It is not expected to have major problems due to interference from UMTS towards WLAN and
Bluetooth, thanks to the different working frequency. On the other hand, particular interest has to
be paid in the interference between Bluetooth and WLAN .Due to the market acceptance of
Bluetooth and WLAN, there is a special interest of designers and portable data devices
manufacturers to improve the coexistence of the two standards. There are many studies showing
the robustness and the reliability of Bluetooth in presence of WLAN and vice versa.
A description of the electromagnetic behaviour of conventional aircraft equipment is necessary to
analyse the interference and the EMC of the new wireless network with the avionics systems. The
allowed radiated field levels are regulated and must be respected if certification is desired. So far,
GSM telephony is prohibited in commercial aircraft due to the uncertain certification situation and
the expected high interference levels of the TDMA technology.

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6. SERVICE INTEGRATOR
The different wireless access services of UMTS, W-LAN and Bluetooth require an integration of
the services over the satellite. The central part of the service portfolio provisioning is the service
integrator (SI), cf. Figure 3. The service integrator will provide the interfaces for the wireless and
wired service access points in the cabin, as well as the interface to the terrestrial networks at air-
com provider site. All services will be bundled and transported between a pair of Service
Integrators. It performs the encapsulation of the services and the adaptation of the protocols. The
SI multiplexer is envisaged to assign variable capacities to the streams, controlled by a bandwidth
manager that monitors also the QoS requirements of the different service connections. Changes in
capacity assignment must be signalled to the SI at the other communication end. The heterogeneous
traffic stream is then sent to streaming splitter/combiner. This unit is envisaged to support several
satellite segments and to perform handover between them. Towards the terminal side, the interfaces
of the wireless access standards need to interwork with the transport streaming of the SI by specific
adaptation layers (AL). These ALs have to be designed according to the analysis of the impact of
delay, jitter and restricted / variable bandwidth on the protocol stack. Buffering (to compensate
delay jumps at handover) and jitter compensation for real-time services (e.g., voice) must be also
provided here.
Figure 6.1 Schematic diagram of Service Integrator

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7. SERVICE DIMENSIONING
This section provides an overview of key issues and steps for the systematic system dimensioning
of Wireless Cabin air-com satellite communications system. We will tackle the satellite
constellations as potential candidates for air-com services as well as the gross traffic calculation
and assignment process. Different market entry options and reference business cases must be taken
into account in an initial stage of a system design. The evolutionary path leads from existing L-
band systems such as INMARSAT GAN (see Figure 5) or B- GAN in few years up to C/Ku band
and existing GEO transponders, whereas the “revolutionary” path may target from the beginning
at advanced K/Ka band technology and the design of a tailor-made, potentially non-GEO system.
The system dimensioning process can be structured in several steps:
(i) Determination of gross traffic per aircraft using the multi-service model
(ii) Determination of the timely and locally varying traffic, depending on the flight path
and flight schedule, assuming also a service rool-out scenario for different airlines and
aircraft types.
(iii) Identification of potential serving satellites and their coverage areas.
(iv) Mapping and traffic allocation of the air-com traffic to the satellite systems.

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8. COLLECTIVELY MOBILE
HETEROGENEOUS NETWORK
Figure 8.1 CMHN model
The concept of having several users, which are collectively on the move forming a group with
different access standards into this group, is called Collectively Mobile Heterogeneous
Network (CMHN). In such a scenario. One can find two types of mobility and two types of
heterogeneity: the mobile group itself and the user mobility inside the group from one side, and
heterogeneous access segments and heterogeneous user access standards from the other side.
The aircraft cabin represents a CMHN supporting three types of wireless (user mobility) access
standards (heterogeneous user access) inside an aircraft (the mobile group) using one or more
satellite access segments. The CMHN may cross coverage areas and then inter-/ intra-satellite
handover will be required. The communication infrastructure to support the cabin CMHN is
depicted in Fig 2. The architecture consists of
(i) Several wireless access segments in the aircraft cabin which can coexist with the
standard wired IP LAN
(ii) A satellite segment for interconnection of the cabin with the terrestrial telecom networks
(iii) An air-com service provider segment supporting the integrated cabin services.

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9. CONCLUSION
Go meet the increasing and ever changing needs of the most demanding passengers a
solution in which passengers, both business and economy, could use their own wireless
equipment must be developed. This approach has many advantages. From the users point of
view, their service acceptance will be increased by the following facts: they can be reached
under their usual telephone number, they may have available telephone numbers or other data
stored in their cell phones or PDAs, their laptops have the software they are used to, the
documents they need and with their personalized configuration (starting web site, bookmarks
address book). In addition, since users in an aircraft are passengers, the electronic devices
they carry with them is wireless, like laptops with WLAN interface. From the airlines point of
view there is a huge saving of the investment that would suppose the installation of terminals
(screens, stations, wired telephones), the consequent software licenses (in case of PCs) and
the further investment due to hardware updating to offer always last technology to their
customers.

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References:
(i) wirelesscabin.triagnosys.com/html/aero.html, 24/04/16
(ii) Personal Satellite Services : 4th International ICST Conference, Yongquiang Cheng,
Kai Xu and Yum Fun Hu, University of Bradford, US
(iii) Secure Operation, Control and Maintenance of modern aircrafts, IEEE Xplore,
25/04/16
(iv) New age cabin system and technologies, Wipro
(v) IRCRAFT CABIN PROPAGATION FOR MULTIMEDIA COMMUNICATIONS
Núria Riera Díaz, Matthias Holzbock German Aerospace Center (DLR), Institute of
Communications and Navigation Wessling-Oberpfaffenhofen, Germany

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