Demonstrator Setup

Each hard- and software service as described in details in D17 has been integrated into the WirelessCabin demonstrator architecture. The road map from the first steps to the final demonstrator architecture is presented within this chapter for the Cabin Service Integration Domain, since it is representative of the entire system.

 

The first ideas and architecture drawings done by the Wireless Cabin project separates each service into a standalone packet integrated on separate machines. Due to restrictions on space and power consumption for the final demonstrator the main evolution goal was to reintegrate the services to a minimal hardware architecture. Therefore the USG, Local Access Gateway, Transport Gateway, Director Simulator and the Content Server were consolidated into only one unit. Only the Billing system runs on a separate machine , because of operating system needs (Windows instead of Linux). Some steps of the evolution in the hardware and software integration can be clearly seen in the figures above. Through this evolution transforming process the final architecture shown in the figure below was developed.

 

Figure 1 Final WirelessCabin architecture (aircraft segment)

 

The Aircraft Service Integrator (ASI) is the core of the aircraft segment. It controls the entire traffic coming in and out of the system and administrates the entire network. Basically, it is a Linux box using SuSE 8.2 as operating system and kernel 2.4.20. The computer itself is a DSM industrial computer, specially designed to run properly in vibrating or unstable environment, like an aircraft in flight. For instance, it has a laptop hard-disk and all cards are more solidly fixed than in a normal computer. As hardware, it is equipped with a 2.4 GHz processor, 6 Ethernet cards (Linked to interfaces eth0, 1, 2, 3, 4 and 5) and one ISDN card (Interface ippp0). It runs a certain number of applications separated in two parts: the Local Access Domain (LAD) and the Service Integration Domain (SID). Initially, they were separated in two different computers but due to volume/weight considerations, they were combined together for the demonstrator. Ideally, they should be separated in a working system but good security and performance management could prevent that.

The blue boxes in the pictures represent devices dealing with the access segments (W-LAN, GSM, Bluetooth) and with the relevant functionalities. Green boxes represent computers storing particular contents for passengers or for the crew, these are optional devices

There were two types of satellite connections used, both using the Inmarsat network.

The first one is using a Swift 64 ISDN channel on the main 4 Inmarsat satellites. These are geostationary satellites. In Europe, three are visible: Atlantic Ocean Region East and West (AOR-E and AOR-W) and, low to the East, Indian Ocean Region (IOR). Together, they offer a worldwide coverage except for Polar Regions above 78° of Latitude (North and South). One Swift 64 channel is offering a dedicated link with 64 kbps (Kilo bits per second) of data rate. On board the Airbus A340-600 used for the test, a phased array antenna is installed at the top of the cabin and a SatCom terminal is mounted in the electronic bay of the plane. Antenna and SatCom terminal are built by Rockwell-Collins.

Figure 2 Satellite Modem

The connection between the ASI and the ground server (the Ground Service Integrator, GSI) is done via the ISDN card on the ASI. The satellite which is used during the flight test is AOR-E and the ground station is located in Burum (Netherlands). After that, the call is routed via the terrestrial ISDN network to the GSI located in Oberpfaffenhofen (Germany).

There are also experiments, using another type of link. The new Inmarsat regional B-GAN (Broadband-Global Area Network) providing up to 144 kbps in a spot beam covering Europe, North Africa and Western Asia. It uses the Thuraya geosynchronous satellites and provides continuous connectivity, charged by the Mbyte of traffic. However, the bandwidth allocated is not guaranteed: it is shared among the users of a given spot beam. It is therefore impossible to provide good real-time applications like voice calls. Yet it would be fine for non-real time traffic. The other problem about using this technology is that antennas do not exist in the form needed to be flown in aircrafts. It therefore was not used during the flight test. However, Inmarsat is planning on an important development of such services in the years to come, forecasting bit rates up to 432kbps, using the new coming 4th generation of Inmarsat satellites, and ability to adapt such antennas and terminals to aeronautical needs.