Wireless Optical Communication Network for Aircraft

Abstract

WIRELESS OPTICAL COMMUNICATION NETWORK FOR AIRCRAFT A wireless optical communication network comprises a gateway router (1a) and a large number of optical network nodes (2a, 2b). The gateway router includes a controllable light source (14), a photodetector (15), and a modulation / demodulation device (12) coupled to the controllable light source (14) and the photodetector (15). Each of the large number of optical network nodes (2a, 2b) comprises, respectively, an optical signal transmission path extending between two optical network interfaces (4a, 4b) of the optical network node (2a, 2b), at least one beam splitter (4) disposed on the optical signal transmission path, and an optical network access point (6) that is coupled to an optical access interface (4c) of the beam splitter (4). [Fig. 1]

Description

Title of the invention: WIRELESS OPTICAL COMMUNICATION NETWORK FOR AIRCRAFT TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a wireless optical communication network ("visible / non-visible light communication") intended for use in an aircraft and to a method of wireless optical communication in an aircraft.

[0002] TECHNICAL CONTEXT

[0003] Wireless optical communications offer a fast and economical alternative to transmitting signals by modulated radio waves. Visible light or light in the near-infrared range, with an electromagnetic spectrum, for example, between 100 THz and 1500 THz, is used as an optical carrier for data transmission for wireless optical communication ("Visible / Non-Visible Wireless Optical Link Communication"). Modulated light is used here for digital data information. The intensity and / or phase of the light generated by a light source, for example, an LED, can be modulated over time to encode data into a light signal. A photodetector receives the modulated light signal, which is decoded to retrieve the transmitted information. Thus, the light source acts as the transmitter and the photodetector as the receiver.Conventional LEDs, which are also used for lighting purposes, can be used for wireless optical communications, since the modulation frequency is several times higher than what the human eye can still perceive as variations in brightness or color.

[0004] Data transmission rates exceeding 100 Mbit / s can be achieved through the use of high-performance LEDs employing various multiplexing techniques – and the data transmission rate can even be increased to 100 Gbit / s through parallel data transmission using multiple light sources or by means of various optical wavelengths transmitted in parallel. In particular, in aircraft, the ability to transmit digital data within a passenger cabin to the terminal devices of passengers, crew, and / or maintenance personnel is of interest due to the ubiquity of personal electronic devices. Conventional passenger aircraft use wired and / or wireless radio networks such as mobile phone networks or networks conforming to the IEEE 802 standard.11 in order to allow passengers to connect to an aircraft network and access the . digital content of an in-flight entertainment program on the Internet or other external networks.

[0005] Unlike wireless radio networks, wireless optical communications have the advantage of not generating electromagnetic interference (EMI) that could affect navigation systems or other electronic components on board the aircraft. Similarly, the reception and transmission quality of wireless radio signals can be degraded due to the large number of passengers on board the aircraft who wish to connect to the aircraft network simultaneously. The data transmission capacity of radio networks eventually tends towards a saturation point. The spectral range of available wireless optical transmissions, which is more than 2000 times greater, overcomes these bandwidth and capacity limitations.

[0006] Documents WO 2009 / 132877 A1, DE 101 07538 B4 and US 2014 / 0226983 A1 disclose examples of wireless optical communication networks intended for use in aircraft. Summary of the invention

[0007] One of the aims of the invention is to find better solutions for the use of wireless optical communication networks in aircraft, which make it possible to increase the reliability and stability of data connections and to simplify the implementation of network components.

[0008] These goals and others are achieved by a wireless optical communication network according to the invention, by an aircraft according to the invention, and by a wireless optical communication method in an aircraft according to the invention.

[0009] According to a first aspect of the invention, a wireless optical communication network comprises a gateway router and a large number of optical network nodes. The gateway router includes a controllable light source, a photodetector, and a modulation / demodulation device coupled to the controllable light source and the photodetector. Each of the large number of optical network nodes comprises, respectively, a wireless optical signal transmission path extending between two optical network interfaces of the optical network node, at least one beam splitter disposed along the optical signal transmission path, and an optical network access point coupled to an optical access interface of the beam splitter.

[0010] According to a second aspect of the invention, an aircraft comprises a wireless optical communication network according to the first aspect of the invention. In certain embodiments, the optical network access points of the large number of optical network nodes may be installed in passenger service units or cabin trim panels of the aircraft. In certain embodiments In implementation, at least two of the large number of optical network nodes are coupled to each other by free-space optical transmission paths to form a bidirectional network connection, and the free-space optical transmission paths extend through cavities in interior trim elements of the aircraft passenger cabin.

[0011] According to a third aspect of the invention, a method for wireless optical communication in an aircraft comprises the steps of establishing a bidirectional optical network connection via a free-space optical transmission path between a gateway router comprising a controllable light source, a photodetector, and a modulation / demodulation device coupled to the controllable light source and the photodetector, and a first of two optical network interfaces of a first of a large number of optical network nodes, of routing the bidirectional optical network connection via an optical signal transmission path in the first of a large number of optical network nodes from the first of the two optical network interfaces to a second of the two optical network interfaces, and of branching,via a beam splitter disposed in the optical signal transmission path, from the bidirectional optical network connection to an optical network access point which is coupled to an optical access interface of the beam splitter. In some embodiments, the method may further comprise the step of creating a bidirectional optical network connection via a free-space optical transmission path between the first and second optical network interfaces of the first of a large number of optical network nodes and an optical network interface of a second of the large number of optical network nodes.

[0012] An important idea of ​​the invention consists not only in the use of free-space data transmission paths between individual network nodes, but also in routing the free-space data transmission paths through the individual network nodes. Optical beam splitters that allow the creation of network branches without the need to convert the received light signals into the electronic domain, and vice versa, between network nodes are used for this purpose within the network nodes.

[0013] A particular advantage of the solutions according to the invention is that a significant increase in data transmission rate can be achieved for applications and services in a data communication network in an aircraft. The robustness and security against interference of the communication connections can advantageously be increased by means of the paths of continuous free-space data transmission. Existing subsystems can also be retained by means of the network architecture according to the invention.

[0014] Due to the use of purely optical free-space data transmission paths, and the passage of these paths through the various network nodes, electrical cabling can advantageously be avoided, with a corresponding weight saving. Furthermore, the overall network architecture can easily be expanded modularly thanks to the end-to-end optical configuration of the connections to the core network. Similarly, advantageous redundancy for network stability and safety against failures can very easily be implemented using end-to-end free-space optical transmission paths by employing different light sources, different spectral transmission frequencies, or by establishing spatially distinct transmission paths.

[0015] Wireless optical communications are characterized by the fact that they avoid electromagnetic interference (EMI), which could interfere with other electrical circuits due to electromagnetic radiation or electromagnetic induction. Furthermore, optical network connections can be easily interrupted by optically opaque elements, which advantageously enhances security against eavesdropping compared to radio networks. Important components of a wireless optical communication system, such as controllable light sources and photodetectors, can also be manufactured economically. These components are also characterized by low power consumption and low heat generation during operation, while exhibiting a long service life and low maintenance requirements.

[0016] Advantageous concepts and improvements will emerge from the other secondary claims as well as from the description with reference to the figures.

[0017] According to certain embodiments of the wireless optical communication network, the optical network access points can each include an optical signal converter which is coupled to the optical access interface of the beam splitter, and a system consisting of a controllable light source and a photodetector coupled to the optical signal converter.

[0018] According to some other embodiments of the wireless optical communication network, the beam splitter may include a beam splitter component selected from the group consisting of a beam splitter blade, a beam splitter cube, a pentagonal beam splitter, a film beam splitter and a Köster prism.

[0019] According to certain other embodiments of the wireless optical communication network, at least two of the large number of optical network nodes can be coupled to each other two by two via free-space optical transmission paths to build a bidirectional network connection. Similarly, in some other embodiments of the wireless optical communication network, the gateway router can be coupled, via a free-space optical transmission path, to one of the two optical network interfaces of one of the large number of optical network nodes to build a bidirectional network connection.

[0020] According to certain other embodiments of the wireless optical communication network, at least one of the large number of optical network nodes may include at least two beam splitters arranged along the optical signal transmission path. A first of said at least two beam splitters is coupled via an optical access interface to the optical network access point. A second of said at least two beam splitters may be coupled via an optical network bifurcation interface of the beam splitter to another of the large number of optical network nodes or to a gateway router.

[0021] According to certain other embodiments of the wireless optical communication network, the wireless optical communication network may further include a network server that is coupled to the gateway router via a wireless radio network or a wired communication interface. This network server may, in certain embodiments, be designed to couple the gateway router to an external network, for example, the Internet.

[0022] According to certain other embodiments of the wireless optical communication network, the wireless optical communication network can be designed according to a full-duplex ring topology or a full-duplex mesh topology, which means that the large number of optical network nodes are optically coupled to each other according to a full-duplex ring topology or a full-duplex mesh topology.

[0023] The concepts and improvements mentioned above may be combined with one another in any way, where relevant. Other possible concepts, improvements, and implementations of the invention include combinations, even if not explicitly mentioned, of features of the invention described above or below with reference to the embodiment examples. In particular, the expert may also add here certain individual aspects as improvements or extensions to the respective basic form of the present invention.

[0024] BRIEF SUMMARY OF THE CONTENTS OF THE FIGURES

[0025] The present invention is described in more detail below with reference to exemplary embodiments shown in the schematic figures, among which:

[0026] [Fig-1] represents a functional diagram of an optical communication network without thread according to one embodiment of the invention;

[0027] [Fig.2] represents a schematic illustration of an aircraft comprising a wireless optical communication network arranged inside the aircraft according to another embodiment of the invention;

[0028] [Fig.3] represents a functional diagram of a variant of a network node of a wireless optical communication network according to another embodiment of the invention;

[0029] [Fig.4] represents a functional diagram of a periscope module intended for use in a wireless optical communication network according to another embodiment of the invention; and

[0030] [Fig.5] represents a flowchart of a wireless optical communication method in an aircraft according to another improvement of the invention.

[0031] The accompanying figures will provide a better understanding of the embodiments of the invention. They illustrate certain embodiments and, in conjunction with the description, explain the principles and concepts of the invention. Other embodiments, and many of the advantages, will become apparent from the drawings. The elements of the drawings are not necessarily shown to scale. Directional terms such as "up," "down," "left," "right," "above," "below," "horizontal," "vertical," "front," "back," and other similar statements are used for explanatory purposes only and do not limit the general scope of the description to specific concepts as illustrated in the figures.

[0032] The elements, features and components of the drawings which are identical, which have the same function or the same effect, are each designated by the same reference codes, unless otherwise indicated.

[0033] DESCRIPTION OF EXAMPLES OF EMBODIMENTS

[0034] In the description presented below, reference is made to wireless optical communications, abbreviated as V / NVLC ("visible / non-visible wireless light communications"). In general terms, wireless optical communications use visible or non-visible light, for example between 100 THz and 1500 THz, as the optical carrier for data transmission. Modulated light is used here for digital data information. The intensity, phase, and / or frequency of the light generated by a light source, for example, a laser, an OLED, an AMOLED, or another controllable electroluminescent light source, can be modulated over time to encode data in a light signal. The modulated light contains the content of the information or strings of numerical characters to be transmitted.

[0035] A receiving module, for example a photodetector, receives the modulated light signal which is decoded / demodulated in order to recover the transmitted information. The light source thus functions as the transmitter, and the photodetector as the receiver.

[0036] Figure 1 shows a schematic illustration of a wireless optical communication network 10 in the form of a functional diagram. The wireless optical communication network 10 can, for example, be implemented in an aircraft, such as the passenger transport aircraft A illustrated as an example in Figure 2.

[0037] A gateway router la which has a wireless radio connection or a wired connection to a network server 20 on board aircraft A acts as a connection point to other external networks - indicated by the numeric reference 30 on Figs. 1 and 2, without limitation of generality - such as the Internet or a satellite network.

[0038] The gateway router la can receive and transmit digital data via a bidirectional data port 11. The bidirectional data port 11 has a communication connection to a modulation / demodulation device 12 of the gateway router la, which is designed to encode digital data for transmission to the wireless optical communication network or to decode digital data received from the wireless optical communication network for transmission to external networks 30. The modulation / demodulation device 12 can use various modulation techniques for this purpose, such as single-carrier modulation techniques based on the deliberate variation of the amplitude, frequency and / or phase of the light frequency which serves as the carrier.Alternatively, the modulation / demodulation unit 12 can use multicarrier modulation techniques such as orthogonal frequency division modulation (OFDM).

[0039] The modulation / demodulation device 12 is coupled to a controllable light source 12, such as an LED, OLED, or laser diode operating in the visible or near-infrared spectrum, via a light source driver 13, on one side, and to a photodetector 15, such as a photodiode, on the other side. The light source 14 and the photodetector 15 enable the physical transmission of data via optical connections. The bidirectionality of the optical data connection can be implemented by using the light source 14 as the transmitter and the photodetector 15 as the receiver.

[0040] A large number of optical network nodes are connected downstream of the gateway router. These network nodes can be designed as network nodes 2a as illustrated in [Fig. 1], or alternatively as array nodes 2b as illustrated in [Fig. 2]. Generally, each optical array node 2a, 2b comprises two optical array interfaces 4a and 4b. An optical signal transmission path extends between the two optical array interfaces 4a and 4b. A beam splitter 4, which diverts an optical signal to an optical access interface 4c of the beam splitter 4, is arranged along the optical signal transmission path. The beam splitter 4 may include beam splitter components 5 suitable for this purpose, for example, a beam splitter blade, a beam splitter cube, a pentagonal beam splitter, a pellicular beam splitter, or a Köster prism. The beam splitter components 5 may be made of dichroic or non-dichroic materials.The beam splitter components 5 can also have a polarizing or non-polarizing effect on the optical beams that pass through them.

[0041] The network nodes 2a or 2b further include an optical network access point 6 which is coupled to an optical access interface 4c of the beam splitter 4. The optical network access point 6 provides an inbound or outbound coupling point for network connections to optical terminal devices 7, i.e. terminal devices 7 which have an optical network interface 7a through which wireless optical communication is possible.

[0042] The optical network access point 6 may initially comprise an optical signal converter 6a coupled to the optical access interface 4c of the beam splitter 4. This optical signal converter 6a can convert an optical signal from the beam splitter 4 into a feed signal for a controllable downstream light source of the optical network access point 6. Similarly, the optical signal converter 6a can receive digital signals from a passenger terminal 7 of an aircraft A via a photodetector of the optical network access point 6 and reinject them, via the beam splitter 4, into the wireless optical communication network. The controllable light source (e.g., an LED, an OLED, or a laser diode operating in the visible or near-infrared spectrum) and the photodetector (e.g., a photodiode) can be implemented in a system 6b.

[0043] System 6b can in particular be installed in aircraft A, in a passenger service unit or in a ceiling or wall panel of a passenger cabin of aircraft A. In particular, wherever light sources are in any way installed for cabin lighting or as reading lamps, the implementation of an additional access point functionality is appropriate.

[0044] As illustrated in [Fig. 2], a plurality of optical network nodes 2a, 2b can be coupled together via free-space optical transmission paths 3a to form a bidirectional network connection. The connection to the gateway router la can be coupled via a free-space optical transmission path 3b to a final network node 2a, 2b in this type of network node chain. The bidirectional network connections thus created between the gateway router la and the network nodes 2a, 2b can be configured according to different topologies. A full-duplex ring topology, which may optionally pass through a network router 1b with amplifiers at opposite ends of the network ring, is illustrated by way of example in [Fig. 2]. The network nodes 2b can further extend the ring topology to mesh-duplex topologies.

[0045] In an aircraft A, the free-space optical transmission paths 3a can advantageously pass through cavities in the interior trim elements of the passenger cabin of aircraft A to create bidirectional network connections between the network nodes 2a or 2b distributed throughout the passenger cabin. The free-space optical transmission paths 3a are thus largely protected against unwanted interference. Furthermore, these cavities are shielded against stray light and variations in lighting conditions within the passenger cabin, resulting in more reliable and stable optical data communications.

[0046] Figure 3 represents another variant of an optical network node 2b which includes another beam splitter 4 in addition to the elements of the network node 2a of Figure 1. This beam splitter 4 is arranged in series with the first beam splitter 4, and is intended to provide a branching option to more nodes of the large number of optical network nodes 2a, 2b or to a gateway router via an optical network bifurcation interface 4d of the beam splitter 4.

[0047] If, due to external conditions prevailing in aircraft A, a straight-line connection between two elements of the wireless optical communication network 10 is not possible, a periscope module 2c according to [Fig. 4] can be used. Such a periscope module 2a can guide the free-space optical transmission path 3a, 3b at angles, such that two beam splitters 8 are each arranged interconnected along the beam path of the free-space optical transmission path 3a, 3b via the respective periscope interfaces 8a or 8b. The beam splitters 9 can also include beam splitter components 8, which may, for example, be a beam splitter blade, a beam splitter cube, a pentagonal beam splitter, or a beam splitter. of a pellicular beam or a Köster prism. The beam splitter components 8 can be made of dichroic or non-dichroic materials. The beam splitter components 8 can also have a polarizing or non-polarizing effect on the optical beams passing through them.

[0048] Figure 5 represents a method M for wireless optical communication in an aircraft. The method M can, for example, be applied in an aircraft A as illustrated in Figure 2. The method M can be implemented here using the components of a wireless optical communication network 10 shown with reference to Figures 1 to 4 in an aircraft A, as schematically represented by way of example in Figure 2.

[0049] In a first step M1, the method M comprises the creation of a bidirectional optical network connection via a free-space optical transmission path 3b between a gateway router la and a first of a large number of optical network nodes 2a, 2b. The gateway router la may for this purpose include a controllable light source 14, a photodetector 15 and a modulation / demodulation device 12 coupled to the controllable light source 14 and the photodetector 15, so that there is an optical communication connection between a bidirectional interface of the gateway router la and a first of two optical network interfaces 4a, 4b of the respective first optical network node 2a.

[0050] In a second step M2, the bidirectional optical network connection is routed via an optical signal transmission path in the first optical network 2a, 2b from the first optical network interface 4a to a second optical network interface 4b. A beam splitter 4, which in a third step M3 splits the bidirectional optical network connection to an optical network access point 6, is arranged along the optical signal transmission path. This network access point 6 is coupled for this purpose to an optical access interface 4c of the beam splitter 4.

[0051] To extend a wireless optical communication network 10, a bidirectional optical network connection can optionally be created at a fourth stage M4 via a free-space optical transmission path 3a between the second optical network interface 4b of the first optical network node 2a, 2b and another optical network interface 4a, 4b of a second optical network node 2a, 2b.

[0052] In the detailed description presented above, various features have been summarized in the form of one or more examples to enhance the relevance of the illustration. It should nevertheless be noted that the description presented above is purely illustrative and should in no way be considered restrictive. It aims to cover all variants, all modifications, and all the equivalents of the various characteristics and examples of implementation. Many other examples will immediately and directly appear to the expert, due to their specialized knowledge, upon reading the description presented above.

[0053] The embodiments have been selected and described in order to illustrate as effectively as possible the principles underlying the invention and their potential practical applications. Thus, specialists will be able to modify and use the invention and its various embodiments optimally for the intended application. The terms "containing" and "comprising" appearing in the claims and the description are used as linguistically neutral terminology for the corresponding term "including." Furthermore, the use of the terms "a" or "an" does not fundamentally preclude a plurality of features and components thus described.

Claims

Demands

1. Wireless optical communication network (10), configured to be carried on board an aircraft and comprising: a gateway router (la) which includes a controllable light source (14), a photodetector (15) and a modulation / demodulation device (12) coupled to the controllable light source (14) and the photodetector (15); and a large number of optical network nodes (2a, 2b), each of which comprises: a wireless optical signal transmission path extending between two optical network interfaces (4a, 4b) of the optical network node (2a, 2b); at least one beam splitter (4) disposed on the wireless optical signal transmission path; and an optical network access point (6) which is coupled to an optical access interface (4c) of the beam splitter (4).

2. Wireless optical communication network (10) according to claim 1, wherein the optical network access points (6) each comprise: an optical network signal converter (6a) which is coupled to the optical access interface (4c) of the beam splitter (4); and a system (6b) consisting of a controllable light source and a photodetector coupled to the optical signal converter (6a).

3. Wireless optical communication network (10) according to any one of claims 1 and 2, wherein the beam splitter (4) comprises a beam splitter component (5) selected from the group consisting of a beam splitter blade, a beam splitter cube, a pentagonal beam splitter, a film beam splitter and a Köster prism.

4. Wireless optical communication network (10) according to any one of claims 1 to 3, wherein the nodes of the large number of optical network nodes (2a, 2b) are coupled to each other at least two by two via free-space optical transmission paths (3a) to construct a bidirectional network connection.

5. Wireless optical communication network (10) according to any one of claims 1 to 4, wherein the gateway router (the) is coupled, via a free-space optical transmission path (3b), to a first of the two optical network interfaces (4a, 4b) of one of the large number of optical network nodes (2a, 2b) to construct a bidirectional network connection.

6. Wireless optical communication network (10) according to any one of claims 1 to 5, wherein at least one of the large number of optical network nodes (2b) comprises: at least two beam splitters (4) disposed on the wireless optical signal transmission path, wherein a first of said at least two beam splitters (4) is coupled via an optical access interface (4c) to the optical network access point (6), and wherein a second of said at least two beam splitters (4) is coupled via an optical network bifurcation interface (4d) of the beam splitter (4) to another of the large number of optical network nodes (2b) or to a gateway router (1a).

7. Wireless optical communication network (10) according to any one of claims 1 to 6, further comprising: a network server (20) which is coupled to the gateway router (la) via a wireless radio network or a wired communication interface.

8. Wireless optical communication network (10) according to claim 7, wherein the network server (20) is designed to couple the gateway router (la) to an external network (30), for example the Internet (30).

9. Wireless optical communication network (10) according to any one of claims 1 to 8, wherein the large number of optical network nodes (2a, 2b) are optically coupled to each other according to a full-duplex ring topology or according to a full-duplex mesh topology.

10. Aircraft (A) comprising a wireless optical communication network (10) according to any one of claims 1 to 9.

11. Aircraft (A) according to claim 10, wherein the optical network access points (6) of the large number of optical network nodes (2a, 2b) are installed in passenger service units or trim panels of a passenger cabin of the aircraft (A).

12. Aircraft (A) according to claim 10 or 11, wherein at least two of the large number of optical array nodes (2a, 2b) are coupled to each other via free-space optical transmission paths (3a) to create a bidirectional network connection, and the free-space optical transmission paths (3a) extend through cavities in interior trim elements of the aircraft passenger cabin (A).

13. A method (M) of wireless optical communication in an aircraft (A), comprising: the creation (Ml) of a bidirectional optical network connection via a free-space optical transmission path (3b) between a gateway router (la) which includes a controllable light source (14), a photodetector (15) and a modulation / demodulation device (12) coupled to the controllable light source (14) and the photodetector (15), and a first of two optical network interfaces (4a) of a first of a large number of optical network nodes (2a, 2b); the routing (M2) of the bidirectional optical network connection via a wireless optical signal transmission path in the first of a large number of optical network nodes (2a, 2b) from the first of the two optical network interfaces (4a) to a second of the two optical network interfaces (4b); and the division (M3) of the bidirectional optical network connection by means of a beam splitter (4) disposed on the wireless optical signal transmission path leading to an optical network access point (6), which is coupled to an optical access interface (4c) of the beam splitter (4).

14. Method (M) according to claim 13, further comprising: the creation (M4) of a bidirectional optical network connection via a free-space optical transmission path (3a) between the second of two optical network interfaces (4b) of the first of a large number of optical network nodes (2a, 2b) and an optical network interface (4a, 4b) of a second of the large number of optical network nodes (2a, 2b).

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