DE102013203134B4 - Communication device and method for exchanging data - Google Patents

Abstract

Communication device for exchanging data between wagons of a rail vehicle network, comprising:
an optical transmission device (16a) which can be attached to a first carriage (12) of the rail vehicle composite,
an optical receiving device (18a), which is attachable to a second carriage (14) of the rail vehicle network,
wherein the optical receiving device (18a) is directed towards the optical transmitting device (16a) so that there is a line of sight between the optical transmitting device (16a) and the receiving device (18a),
wherein the data transmission takes place in the form of a free-space optical transmission,
characterized in that a first and second lens (20a, 20b) each on the side facing away from the carriage (12, 14) side of a hinge (19a, 19b) and mechanically over a variable in its length pipe (22a, 22b) are interconnected, wherein the lenses (20a, 20b) about the joints (19a, 19b) are pivotable and are automatically aligned by the tube (22a, 2b) to each other.

Description

There is a need to exchange data between individual wagons of a rail vehicle network. This may be control data (ie safety-relevant information) or else so-called comfort data. The data mentioned can have different formats and, accordingly, sometimes require special plug-in connections for a wired transmission. Thus, it is necessary to provide a large number of mostly proprietary plug connections with different voltage levels and various data protocols between two carriages of a rail vehicle network.

Furthermore, future scenarios may exist in which at least in phases individual wagons of a stationary or moving rail vehicle network are not physically coupled to each other. For example, individual wagons of a train group can travel at a certain distance one behind the other, as long as they are individually driven (eg FlexCargoRail vehicles). Even between such cars of a rail vehicle network data must be exchanged. This is in the mentioned scenarios via a contact connection, i. H. wired, not possible.

There are various radio-based methods for communication between cars of a vehicle network. They are based, among other things, on IEEE 802.11 (WiFi), UltraWideBand (UWB) or other proprietary wireless communication methods.

The aforementioned radio-based methods have various disadvantages: Depending on the location of use, only very limited frequency bands are available, sometimes with very narrow bandwidths. In addition, they are sometimes very prone to failure. Possible available frequency bands are not protected for safety-critical applications. The achievable data rates may also be insufficient, especially considering the ever-increasing demands for the transmission of high-rate comfort data. In addition, the data formats or protocols of the data must be adapted to the radio system.

Furthermore, known radio methods are difficult to secure in terms of data technology because the frequent changes in the composition of the individual wagons to rail vehicle associations make the administrative outlay (for example the key exchange) relatively expensive.

DE 10 2010 036 521 A1 describes a device for transmitting data between two rail vehicles, wherein the data transmission takes place by means of optical radio communication.

WO 03/098845 A2 describes a device for transmitting data on the infrared principle.

JP 2000-194459 A also describes an apparatus for optically transmitting data.

The object of the invention is to provide a flexible and reliable device for exchanging data between cars of a rail vehicle network and a corresponding method, wherein a high data transmission rate can be achieved.

The object is achieved according to the invention by the subject matter of claims 1 and 9.

The communication device according to the invention for exchanging data between cars of a rail vehicle network comprises an optical transmission device, which can be attached to a first car of the rail vehicle network, and an optical receiving device that can be attached to a second car of the rail vehicle network. The optical receiving device is directed towards the optical transmitting device so that there is a line of sight between the optical transmitting device and the optical receiving device. According to the invention, the data transmission takes place in the form of an optical free space transmission.

This means that between the individual cars of the rolling stock network no data lines and in particular no optical fibers are necessary.

Preferably, each car at its two ends to a transmitting and receiving device which can communicate with an optical transmitting and receiving device of a second car. This is therefore a bidirectional system that allows data exchange in both directions.

The inventive device provides a very high data rate of more than 1 Gbit / s, so that a plurality of different data formats can be transmitted simultaneously. The high available data rate eliminates the need to adapt all previous communication standards to a common radio interface. So far, this has not been possible with the available bandwidths in radio systems. Further details of this feature are described in the present application in connection with the method according to the invention.

Further advantages of the invention lie in the conflict-free use of a data transmission by light signals (reuse factor = 1), since the optical free space transmission generates no interference or is prone to such. Another significant advantage is the inherent data security assurance, in that each listener would be recognized immediately.

Between the optical transmitting device and the optical receiving device is preferably ever optics for expanding (transmitter) and bundling (receiver) of the light signals are used. In this case, the lenses may have a diameter of at least 2 cm. By using lenses of the dimensions mentioned above, it is possible to compensate for local soiling on the lenses, which may be caused by snowfall, rain, etc. The larger the aperture diameter is chosen, the more tolerant the system is to the interference particles on the aperture. If the system is mechanically protected against interfering particles, the aperture can be made smaller. In a bidirectional system, it is preferred that the transmit and receive apertures have the same dimensions. In a unidirectional system, it may be useful to make the receiving lens larger than the transmitting lens for bridging larger distances.

Disturbing factors such as rapid fall, rain, fog, etc. can also be compensated by sending out a stronger light signal. Data protection protocols are also used.

In a preferred embodiment, the optical transmitting device is a laser light source and the optical receiving device is a photodiode with downstream electronics (receiver front end).

It is also possible to provide a cleaning device for cleaning the two lenses. This may be, for example, a windshield wiper.

Furthermore, it is possible to provide a shielding device for shielding the transmission path between the optical transmission device and the optical reception device from external influences, in particular from the effects of weathering. This shielding device can simultaneously be a privacy screen for outside people. This is useful when using a laser light source. It is possible that the shielding device only shields the two lenses and only part of the transmission path.

Furthermore, it is possible in the area of the lenses and / or the shielding device to provide a heating device, for example a heating spiral, in order to protect the lenses from weather influences, in particular from icing.

Furthermore, it is possible to use the communication device according to the invention in connection with a radio system as a two-channel system. As a result, a redundant data transmission for safety-critical applications can be achieved.

Furthermore, it is possible to use certain control systems, eg. B. to control an air brake by the communication device according to the invention ("drive by optics"). In this case, the air brake could be controlled by signals that are transmitted by the communication device according to the invention, in which case a reliable transmission of these signals would have to be ensured accordingly.

In one embodiment, the communication device according to the invention comprises a pivoting device for pivoting the light beam generated by the transmitting device in dependence on an angular offset between the optical transmitting device and the optical receiving device. The pivoting device may be a pivotable mirror, by which a deflection of the light beam of the transmitting device takes place. Alternatively, a joint may be provided around which the transmitting device itself is pivotable so that the direction in which the light beam is emitted is variable.

Furthermore, it is inventively provided that a first and second lens are each arranged on the side facing away from the car of the rail vehicle composite side of a joint and that the lenses are pivotable. The lenses are connected to each other via a variable in length tube. Due to the pivotability of the lenses around the joint and their mechanical connection through the tube, the lenses are automatically aligned with each other.

Furthermore, for compensating an angular offset between the transmitting device and the receiving device, the receiving device may be a receiver array and in particular a photodiode array, in which a multiplicity of receiver elements, in particular photodiodes, are arranged flat next to one another. This receiver array is arranged in the focal plane of the reception lens and can, for example, have 90 × 90 receiver elements with a pitch of 200 μm. This would be sufficient, at a focal length of 100 mm, an angular offset between the transmitting and receiving device (and thus between the two cars of the Rail vehicle network) of 10 °. Corresponding photodiode arrays are described, for example, at http://sales.hamamatsu.com/assets/pdf/parts_G/g8909-01_kird1053e03.pdf. In the same way to the receiver array, an array of transmit lasers may be used for more directional radiation of the sense signal and alignment of the transmit beam to the receiver. Corresponding laser diode arrays of vertical cavity surface emitting lasers (VECSEL) are described, for example, below
htttp: //www.photonics.com/Article.aspx? AID = 21251 or http://www.ulm-photonics.com/new/images/publications/2010pw_120_gbps_vcsel_arrays_fabrication_and_quality_aspects.pdf

Instead of an optical transmitting device and an optical receiving device, through which the data transmission takes place in the form of a free-space optical transmission, one side of the transmission path between the car instead of an optical-electrical conversion with an active transmission laser can also be replaced by an optical fiber (optical fiber). In this embodiment, the transmitting and receiving light is connected via a lens system directly to the glass fiber. The transmitted and received light is still transmitted via an optical free space transmission according to the invention described so far. However, in this way, for example, a de-energized wagon within a rail network can be bridged by passing the signal arriving at the first end of this de-energized wagon over a clearance transmission path through the fiber to the nearest free space transmission at the other end of the de-energized wagon where it is in the same way (ie via a coupling through a lens system) is connected directly from the glass fiber to the free space transmission path.

The invention further relates to a method for exchanging data between wagons of a rail vehicle network, wherein data is transmitted from an optical transmitting device on a first car of the rail vehicle network to an optical receiving device on a second car of the rail vehicle network in the form of a free-space optical transmission. In the context of the method according to the invention, the communication device according to the invention is used for data transmission.

According to the invention, the entire frequency bandwidth of a sampled data signal is shifted into a suitable transmission range for the optical free space transmission ("upmixing"). Subsequently, an optical transmission of the frequency-shifted data signal from the optical transmitting device to the optical receiving device takes place. After that, the frequency-shifted data signal received by the receiving device on the receiver side is shifted back to its original frequency range ("downmixing") and synthesized.

For the optical free space transmission, a data transmission rate between 1 Gbit / s to 40 Gbit / s can be used. The stated rates and underlying bandwidths are used in single-channel systems (i.e., a color of the laser used, for example, at 193 THz). It is also possible to transmit several channels in parallel (Wavelengh Division Multiplex - WDM). In this case, the specified data transfer rate per channel of z. For example, multiply 40 Gbps by the number of channels.

The aforementioned method steps eliminate the need to adapt the previously used communication standards to a common radio transmission interface. This is made possible by the available very high data rate, which is not feasible with the available bandwidths in radio systems.

If, for example, an analog signal is present at the first carriage, it can be scanned in a high-rate manner and then shifted with its entire frequency bandwidth into the frequency range which is available for the optical free-space transmission. On the receiver side, the signal can be shifted back and synthesized accordingly.

In the following, a preferred embodiment of the invention will be explained with reference to figures.

The 1 shows a schematic view of a first embodiment of the communication device according to the invention.

The 2 shows a schematic view of a second embodiment of the communication device according to the invention.

The first car 12 according to 1 an optical transmitter 16a on, the light signals in the direction of the first lens 20a sending out. The light signals are in the direction of the second lens 20b transmitted. In the focal plane of the second lens 20b is the receiving device 18a of the second car 14 ,

The second car 14 in turn has a transmitting device 16b which can be used to data in the direction of the first car 12 to convey. These are there from the second receiving device 18b receive. The sending device 16a and the receiving device 18b are in the focal plane of the first lens 20a arranged.

To the transmission distance between the two lenses 20a . 20b To protect against the weather is a shielding device 22 intended. This can be an outer shielding element 22a include that with the second cart 14 is connected and further a second inner shielding 22b that with the first car 12 connected is. The inner shielding element 22b is in the outer shielding element 22a pushed.

Furthermore, heating coils 24a . 24b be provided by the particular lens 20a . 20b can be protected against icing.

In a further embodiment according to 2 For example, the system may be mechanically coupled by two joints so as to eliminate the need for an automatic alignment system to maintain alignment.

The optical part of the transmission u. Receiving system is located behind a joint 19a . 19b and is automatically aligned by the mechanically connected tube. This can also be done together with the shielding device 22 be installed. In particular, the change in length of the tube could, as in the embodiment described above with the elements 22a and 22b be implemented by one another and thus in the composite in a variable length connection.

Claims (9)

A communication device for exchanging data between wagons of a rail vehicle network, comprising: an optical transmission device ( 16a ) on a first car ( 12 ) of the rail vehicle composite is attachable, an optical receiving device ( 18a ) to a second car ( 14 ) of the rail vehicle composite is attachable, wherein the optical receiving device ( 18a ) in the direction of the optical transmitting device ( 16a ) so that a line of sight between the optical transmitting device ( 16a ) and the receiving device ( 18a ), wherein the data transmission takes place in the form of a free-space optical transmission, characterized in that a first and second lens ( 20a . 20b ) on each of the cars ( 12 . 14 ) facing away from a joint ( 19a . 19b ) are arranged and over a variable in length tube ( 22a . 22b ) are mechanically connected to each other, wherein the lenses ( 20a . 20b ) around the joints ( 19a . 19b ) are pivotable and through the pipe ( 22a . 2 B ) are automatically aligned with each other. Apparatus according to claim 1, characterized in that between the optical transmitting device ( 16a ) and the optical receiving device ( 18a ) a first and second lens ( 20a . 20b ) for bundling the optical transmission device ( 16a ) emitted light signals are arranged, wherein the lenses ( 20a . 20b ) in particular have a diameter of at least 2 cm. Device according to one of claims 1 or 2, characterized in that the optical transmitting device ( 16a ) a laser light source and the optical receiving device ( 18a ) is a photodiode. Device according to one of claims 2 or 3, characterized by a cleaning device, in particular a windscreen wiper for cleaning the first and second lens ( 20a . 20b ). Device according to one of claims 1-4, characterized by a shielding device ( 22 ) for shielding the transmission path between the optical transmission device ( 16a ) and the optical receiving device ( 18a ) against external influences, especially from the weather. Device according to one of claims 1-5, characterized by a pivoting device for pivoting of the optical transmitting device ( 16a ) in response to an angular offset between the optical transmitting device ( 16a ) and the optical receiving device ( 18a ), wherein the pivoting device is a pivotable mirror or a joint around which the optical transmitting device ( 16a ) is pivotable. Device according to one of claims 1-6, characterized in that the optical receiving device ( 18a ) and / or the transmitting device ( 16a ) is a transmitter or receiver array, in particular a photodiode array, in which a plurality of transmitting and / or receiving elements, in particular photodiodes, are arranged side by side on a surface around the focus (focal plane), by an angular offset between the optical transmitting device ( 16a ) and the optical receiving device ( 18a ). Device according to one of claims 1-7, characterized in that one side of the optical free space transmission path at a first end of a carriage instead of an optical-electrical conversion is replaced by an optical waveguide, wherein the transmitting and receiving light via a lens system directly integrated into the optical waveguide so, in particular currentless car of a rolling stock network is bridged by the signal that arrives at the first end of the car through a Freiraumübertragmittlungsstrecke is passed through the optical fiber to the next free space transmission path at the second end of the particular de-energized carriage and there in the same way, ie by a coupling by a lens system of Fiber optic cable to the next free space transmission path, is connected. Method for exchanging data between cars ( 12 . 14 ) of a rail vehicle network, the method comprising: transmitting the data from an optical transmission device ( 16a ) on a first car ( 12 ) of the rail vehicle network to an optical receiving device ( 18a ) on a second car ( 14 ) of the rolling stock network, in the form of a free-space optical transmission, characterized by the following additional steps: shifting the entire frequency bandwidth of a data signal into the optical frequency range for free space transmission (upmixing), optically transmitting the frequency-shifted data signal from the optical transmission apparatus ( 16a ) to the optical receiving device ( 18a ) by means of the communication device according to one of claims 1 to 8, shifting back the entire frequency bandwidth of the optical receiver ( 18a ) received frequency-shifted data signal on the receiver side in its original non-shifted frequency range (downmixing).

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