Wireless audio transmission of information between seats in a mobile platform using magnetic resonance energy

This application is a continuation of U.S. patent application Ser. No. 11/130,557 filed on May 17, 2005. The subject matter of the present application is also generally related to U.S. patent application Ser. No. 11/130,549, filed on May 17, 2005. The entire disclosures of each of the above applications are incorporated herein by reference.

The present invention relates to the transmission of wireless information between seats in a mobile platform, such as in a commercial aircraft, and more particularly to the transmission of audio information using inductive magnetic energy to wirelessly transmit the information from one seat to another in the mobile platform.

On various forms of mobile platforms, and particularly on commercial aircraft, In-Flight Entertainment (IFE) systems are required to send video streams to an aircraft passenger's video display unit, and synchronized audio streams to a headphone jack in a passenger's PCU (Passenger Control Unit) or to some other audio speaker. Typically, the video display is located in the seatback of a seat disposed in a first seat row. The audio signal that is associated with the video content displayed on the video display, however, typically needs to be supplied to an audio jack or speaker that is typically located in a seat in a second seat row behind the first seat. Thus, the video and audio streams must be delivered to two separate network “clients”, but still played in near-perfect synchronization. This is considerably different than the typical network or internet situation where the video and sound signals are played on the same client/host apparatus.

In the past, IFE systems have generally been hard-wired systems. The audio and video signals have been delivered as analog or digital signals to one or the other of the first or second seats described above. Feedforward or feedback cables have been used to send the analog signal to the “other half” of the client. For example, if the audio and video signals were delivered to the first seat, then feedback cables were used to supply just the audio signal to the audio jack or speaker associated with the second seat.

With modern systems, there is a strong desire to move towards completely wireless, digital delivery of both video and audio signals to all of the seats within a mobile platform, such as within a commercial aircraft. Often the video and audio streams are compressed before being transmitted from a wireless access point (or points) within the cabin of the mobile platform to the seats. With this arrangement, the video and audio streams must be decompressed/decoded at the “client end” of the network connection (i.e., at least at one seat location). One option would be to send the video and audio streams separately to the two clients (or the combined stream to both clients). However, in that situation the separate decoding at the two clients can lead to audio playout that is out of synch with the video playout. Therefore, it is desirable to decode both video and audio at one client, and then send decoded audio or video to the “other half” of the client (i.e., to the other seat that did not initially receive both streams of information). It would be highly desirable to accomplish the feedforward/feedback of one or the other of video or audio signals without the use of electrical cables. Eliminating the use of electrical cabling for the feedback information stream being transmitted to one of the seats would enable a completely wireless system to be implemented. This would save cost and weight, and reduce the complexity of installation of an IFE system within a mobile platform.

The present invention is directed to a system and method that enables information to be transmitted from one electronic subsystem associated with the first seat in a mobile platform, to a second subsystem associated with a second seat in the mobile platform, by using inductive magnetic coupling. In one preferred implementation an inductive magnetic transmitter is employed in connection with a first seat. An inductive magnetic receiver subsystem is employed in connection with a second seat that is located closely adjacent the first seat, such as, for example, directly behind the first seat. An RF wireless transceiver in the first seat receives audio/video stream data from an access point located remotely, and decodes the video and audio streams. The video data is sent to the video display in that seat, whereas the audio data is provided to an inductive magnetic transmitter subsystem, which includes an inductive transducer. An inductive magnetic receiver subsystem is located at the second seat which includes an inductive transducer for receiving the inductive magnetic energy from the inductive transducer of the transmitter subsystem located at the first seat. The inductive transducer of the receiver subsystem generates electrical signals that are output to a receiver on the second seat. The receiver generates information that is output to a user accessible component, for example, an audio jack or an audio speaker, associated with the second seat. Advantageously, the inductive magnetic energy transmitted between the transmitter and the receiver subsystem is of very low power and the field strength drops off rapidly with distance from the transmitter. In addition, it operates in a frequency band that is not used by radio frequency communication equipment on board commercial aircraft. For these reasons, it does not give rise to interference problems with other electronic equipment in the vicinity of the first and second seats.

By using the inductive magnetic coupling described above, the video or audio portions, or other information received by the RF transceiver subsystem at the first seat, can be relayed to the receiver subsystem at the second seat without the use of any cables. This enables an entirely wireless system to be implemented with an IFE system. The ability to implement a completely wireless system saves cost, weight and reduces complexity of the installation of an IFE system on a mobile platform.

The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments.

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a simplified view of a commercial aircraft in which a preferred embodiment of the present invention is implemented, and further illustrating various components that supply information to the seat locations on board the aircraft;

FIG. 2 is a simplified perspective view of a portion of the interior of an aircraft illustrating two seat rows at which a preferred embodiment of the present invention is implemented; and

FIG. 3 is a simplified block diagram of a preferred implementation of the present invention.

The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

Referring to FIG. 1 , a system 10 in accordance with the present invention is illustrated being implemented on a mobile platform, in this example a commercial aircraft 12 . It will be appreciated immediately, however, that the system 10 can be readily implemented on a wide variety of other mobile platforms such as ships, trains, buses, rotorcraft, and virtually any other form of mobile platform. The system 10 can just as readily be implemented in terrestrial structures such as theatres, lecture halls, stadiums, etc.

With further reference to FIG. 1 , the system 10 typically receives information from an In-Flight Entertainment (IFE) system 14 located on the aircraft 12 . The IFE system 14 typically includes at least a network server 16 in communication with a wireless local area network (LAN) 18 . The wireless LAN 18 is in communication with a plurality of wireless access points 20 typically spaced apart within a cabin area 22 of the aircraft 12 at overhead locations within the cabin area 22 . Typically one wireless access point 20 is used to relay information content to one or a plurality of rows of seats 24 in the cabin area 22 . The information, in one form, may comprise both video and audio streams that are received at electronic components at each seat in each seat row, decoded, and presented to the occupants of the seats for use. Two of the seat rows 24 and 25 have been labeled for discussion purposes.

With reference now to FIG. 2 , seat rows 24 and 25 are illustrated with the components comprising one preferred implementation of the system 10 . In this example seats 24 A, 24 B, and 24 C make up a first seat row and seats 25 A, 25 B and 25 C make up a second seat row. Each seat 24 A- 24 C, 25 A- 25 C includes an armrest 26 , and each armrest includes a user accessible personal control unit (PCU) 28 . Each seat 24 A- 24 C, 25 A- 25 C also includes an inductive magnetic transmitter subsystem 30 and an inductive magnetic receiver subsystem 32 . For the purpose of discussion, only the transmission of information between seat 24 A in the first seat row and seat 25 A in the second seat row will be described. It will be appreciated, however, that this description applies equally to seat pairs 24 B/ 25 B and 24 C/ 25 C. Also, the information transmitted between seat pairs 24 A/ 25 A, 24 B/ 25 B and 24 C/ 25 C can be on separate channels to avoid interference. However, a principal advantage of the present invention is that the low power magnetic coupling has two characteristics which enable channels to be reused at seat rows that are two or three rows apart from one another: the signal is transmitted at low power levels, and the magnetic field strength drops off rapidly with distance from the transmitter (generally with the inverse of distance to the sixth power). These factors, along with the fact that the transmitter 30 generally operates at frequencies not typically used by RF communication devices, tend to eliminate the risk of interference that would otherwise be present with higher power RF signals

Referring to FIG. 3 , the inductive magnetic transmitter subsystem 30 of seat 24 A and the inductive magnetic receiver subsystem 32 of seat 25 A will be described. Again, it will be appreciated that each subsystem 30 is identical in construction and operation to the other subsystems 30 located on the other seats 24 b , 24 c , 25 b , 25 c . Similarly, each receiver subsystem 32 is identical in construction and operation to the others.

An RF transceiver 34 associated with each seat 24 , 25 receives the RF information content from one of the wireless access points 20 . The video component of this information is transmitted to a video display unit 35 . Electronic subsystem 36 receives only the audio portion of the information content from the transceiver 34 . The electronic subsystem 36 decodes the audio signals, if the signals are compressed, and generates an output signal that is sent to transmitter 37 and thereby applied to an inductive transducer 38 . The inductive transducer 38 generates low power inductive magnetic energy 40 that is transmitted to the receiver subsystem 32 of seat 25 A. Since the component pairs 30 / 32 associated with each seat pair 24 A/ 25 A, 24 B/ 25 B and 24 C/ 25 C can operate on different channels, the magnetic energy 40 does not interfere with communications between seat pairs 24 B/ 25 B and 24 C/ 25 C.

With continuing reference to FIG. 3 , the inductive magnetic energy 40 is received by an inductive transducer 42 of the receiver subsystem 32 at seat 25 A. The inductive transducer 42 generates an output signal to a receiver 44 associated with seat 25 A which is representative of the information content transmitted via the wireless RF link from the wireless access point 20 . This information represents audio signals and is output to an audio jack 46 of PCU 28 of seat 25 A. Alternatively, an occupant seated at seat 25 A could use a wireless magnetic resonance headset (for example, a noise-canceling headset) that is brought on-board by the occupant, or possibly supplied by the operator of the aircraft 12 . In either event, the system 10 operates to “feed back” the audio portion of the content relayed via the RF wireless link using only low power magnetic resonance devices (i.e., subsystems 30 and 32 ).

In an alternative implementation, the video portion of the signal received at seat 25 A could be “fed forward” to seat 24 A. With such an implementation, typically the video portion of the wireless RF signal received at seat 25 A would be fed forward using inductive magnetic coupling to the seat 24 A in front of it. It will be appreciated that other types of electrical signals could just as readily be fed wirelessly between the seat pair 24 A/ 25 A and that the system 10 is therefore not limited to transmitting just audio or just video signals.

The various preferred embodiments described herein enable low powered, inductive magnetic coupling between the electronic components of adjacent seat pairs and therefore eliminate the need for cabling to be run between adjacent seat pairs. This significantly simplifies the installation and removal of the seats within a mobile platform, and particularly within a commercial aircraft, where often hundreds of seats may be employed. This enables faster and less costly seat reconfiguration, so that, for example, an airline might find it more cost-effective to change seating configurations seasonally, or an airplane leasing company might more easily configure leased airplanes for different airline customers. The elimination of physical cabling between adjacent seat pairs helps to reduce the overall weight of the mobile platform, as well as the cost of implementing an IFE system.

While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.