Until recently, the use of mobile communications on board computer was impossible. This prohibition was determined by the fact that mobile phones are inherently uses three frequencies (MHz): GSM-800, GSM-900 and GSM-1800. However, at the same frequencies navigation systems are placed on the board, and therefore the operation of mobile communication devices in an aircraft may cause interference and result in failure of the aircraft radio and catastrophic consequences.
In 2008 the two companies Airbus and Boeing independently began to research the issue. They found in several experimental aircraft a number of mobile phones and watched the results within six months. During this period no change in the operation of aircraft navigation systems were found. Based on these studies were allowed to use mobile phones on board aircraft of these manufacturers.
During the flight at a given tier aircraft is at a distance of ground base stations, and therefore the transmitter mobile phones are set to maximum transmission. But the distance is too great and the connection is not established. To solve this problem and reduce the power transmitting mobile devices onboard computer was asked to place a "cell" network.
Airbus Company has developed and proposed a method to solve this problem, known as GSM services On-Board aircraft (GSMOB) . According to him onboard PC vstanovlyuyetsyaNetwork Control Unit (NCU), which transmits a signal to a higher force levels and provides regular communication and Airborne GSM Server (AGS).
All this equipment creates a small "cell" GSM network on board (Fig. 128). Contact with the ground is organized via satellite link.
Structure of GSM services On-Board aircraft (GSMOB)
In General onboard GSM consists of two segments: ground-based and airborne.
The on-board segment contains:
- one or more base transceiver- transmitting stations (Base Transceiver Station - BTS) that provides connectivity with mobile devices of passengers;
- a control unit (NCU) , which provides control over all mobile devices that use wireless data network. NCU provides control over the radio frequency range of each of the enabled mobile devices and monitors mobile devices that try to connect to the external cellular network;
- the antenna system;
- server equipment of network of GSM (AGS) and his controlstand. AGS provides performance of all functions of controller of the base station of mobile communication
- equipment for provision of satellite communication (Cabin Satellite Data Unit (CSDU).
Fig. 128. Structure of GSMOB
An example of the placement of the onboard equipment GSMOB on the aircraft shown in Fig. 129.
Ground segment consists of ground equipment for satellite communication services and equipment, providing access to the terrestrial network communications and data exchange
To reduce the influence of the transmitters of mobile devices on-Board equipment of aircraft for connection with ground equipment GSM network is allowed to use the services of GSMOB at an altitude of over 10,000 feet above the underlying surface.
Fig. 129. An example of the placement GSMOB on the A320 aircraft : a - switch on/off; remote control system attendant; the indicator permits the use of communication services; d and e antennas; e - BTS; - antenna satellite communication services; and - AGS; K, l - NCU; m and n CSDU
The use of such systems allows to use the services of access to the Internet and mobile communications on-board of aircraft. Service charge is carried out in accordance with the requirements of roaming and by agreement between the airline and the company-provider of mobile communication services. Services of GSMOB are paid as well as roaming services.