seminer report aeronautical_communication

Aeronautical Communication

AERONAUTICAL COMMUNICATION

SEMINAR REPORT

Submitted by

Subhajit Ghosh Semester: 6th

Department: Computer Science & 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

1


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)

1


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.

2


TABLE OF CONTENTS

1. Abstract ----------------------------------------- 32. Introduction ----------------------------------- 63. Wireless Cabin Architecture ----------------- 7

3.1 The architecture --------------------------- 74. Satellite Connection --------------------------- 9

4.1 General architecture ---------------------- 95. Technical Overview --------------------------- 11

5.1 UMTS -------------------------------------- 115.2 Bluetooth ----------------------------------- 125.3 IEEE 802.11 (LANs) --------------------- 14

6. Interference ------------------------------------- 157. Service Integrator ------------------------------ 168. Service Dimensioning ------------------------ 179. CMHN ------------------------------------------- 1810.Conclusion --------------------------------------- 19

3


LIST OF TABLES AND FIGURES

1. The wireless functional architecture (figure2.1) -------------------------------------- 72. Satellite system for aeronautical communication architecture(figure 3.1) ------ 103. UMTS network architecture(figure 4.1) ---------------------------------------------- 124. State diagram of link layer state machine(figure 4.2) ------------------------------- 135. Schematic diagram of Service Integrator (figure6.1) ------------------------------- 166. CMHN model (figure 8.1) -------------------------------------------------------------- 19

4


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

5


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

6


network 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.

7


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).

8


Figure 3.1 Satellite system for aeronautical communication architecture

9


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.

10


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.

11


4.2.1 State MachineThe 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

12


example, a 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 (WIRELESS LAN 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.

13


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.

14


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

15


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.

16


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

17


(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.

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.

18


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

19