Background

Current telephones installed on airplanes are very expensive to use ($4 to $13 per minute).  The utilization rate is about one call per flight and the telephones often suffer damage because kids play with them.  The systems generally add weight to airplanes with a limited return ($$$) on the investment.  In many planes the legacy phone systems are being phased out and they are no longer being installed on new airplanes.  The current telephone technology also forces that you “swipe your card”, which physiologically feels like “real money.”  There has been no effort to personalize (contacts, calendars, text messaging, etc.) these systems, as there is no monetary incentive to develop new technologies or features.  The onboard phone cannot receive calls from the ground, and there is generally a learning curve to using the phone because no two systems are alike.  In short, and considering mobile telephone standards of today, the telephone systems onboard aircraft are lagging mobile telephone standards by at least two decades.

There has been much investigation into the use of mobile phones aboard aircraft during flight. Technologies are being developed that should allow the use of mobile phones without fear of interference with aircraft controls or ground wireless networks. The new technologies are largely based on picocells, where the cabin of the airplane becomes a mini cell in the mobile phone network. The picocells interface with onboard control, transmission, and reception systems.


Onboard “control” of the mobile phone is required for the following reasons:

- Limit power out to reduce the potential of cell phone RF transmissions of  interfering with onboard electrical and electronic systems

-   Limit power out to reduce the engagement of multiple land based cell networks from the cell phone on the airplane

Control RF environment inside the airplane to limit the reception of land based signals

Studies from Carnegie Mellon research in October of 2006 show that some cell phones are “on” during flight.  On average 1 to 4 cell phone calls are made from every commercial flight in the northeast U.S.  Control Channels from terrestrial cell towers can be “seen” inside of the cabin at 35,000ft.

If cell phones are allowed to be “On” and used during flight, things to consider are……..

-     Somehow control all types of cell phones (GSM, CDMA, etc.) on the airplane

- Reduce transmitted power levels of the cell phones

- Prevent cell phones from “seeing” terrestrial Control Channels

- Provide services that are similar to that on the ground

- Voice, SMS text, GPRS

- Must be fully manageable by the cabin crew (social aspects).

- Not interfere with airplane systems

- Not interfere with ground networks

This airborne system is currently being developed around the telecommunication system component commonly known as a picocell.  A picocell is wireless communication system typically covering a small area, such as in-building (offices, shopping malls, train stations, etc.), or more recently in aircraft. A picocell is analogous to a WiFi access point.  In cellular wireless networks, such as GSM, the picocell base station is typically a low cost, small (typically A4 paper size, and about 2-3cm thick), reasonably simple unit that connects to a Base Station Controller (BSC). Multiple picocell 'heads' connect to each BSC: the BSC performs radio resource management and hand-over functions, and aggregates data to be passed to the Mobile Switching Center (MSC) and/or the GPRS Support Node (GSN).