EP2487665A1 - Data transfer method and line of sight independent system - Google Patents

Abstract

The data related to electromagnetic radiation (R1) of a transmitter (S) in a vehicle (1a) or in a transport infrastructure object, is encoded. Reflectors are adapted to electromagnetic radiation, to emit partially reflected electromagnetic radiation (R2). The reflectors are arranged so that the emitted electromagnetic radiations are received by a receiver (E) located in vehicle or in transport infrastructure object. The partially reflected electromagnetic radiation is received by receiver. An independent claim is included for system for visual connection independent data transmission from transmitter to receiver in car-to-car or car-to-infrastructure communication system.

Description

The invention relates to a method for visual connection-independent data transmission from a transmitter to a receiver in a car-to-car or car-to-infrastructure communication system. The invention also relates to a system for visual connection-independent data transmission.

Car-to-X (Car-to-Car) communication services used in future road vehicles are known in the art. These communication services allow the exchange of data and information between motor vehicles with each other or between motor vehicles and traffic facilities. The communication standard is recorded in IEEE 802.11p. The communication between vehicles with each other and vehicles and infrastructure should be used in particular to warn subsequent, oncoming and laterally arriving traffic from dangerous situations. One possible scenario is, for example, the warning of road users from fast-moving emergency vehicles with blue light, in order to avoid a possible collision at traffic light intersections with the blue light vehicle crossing at red.

Since, according to the IEEE 802.11p standard, the communication takes place at comparatively high frequencies of typically 5.8 GHz, so-called line-of-sight propagation is required for the data exchange. This means that in many cases direct visual contact between sender and receiver of the message must be present. If direct visual contact is restricted, for example, by buildings, communication is insufficient or not possible at all.

In previous approaches to solve this problem, an active node is usually used (see. EP 21 78 064 and DE 10 2008 015 778 ). This receives the signals from the transmitter, evaluates them in their own electronics and forwards them to the recipient after processing. Such systems are very expensive, require external power supply and are maintenance-prone by the complex electronics.

In other areas, in particular radar tracking, reflectors have long been in use, making visible a structure otherwise permeable to electromagnetic waves. Examples of such devices are those in DE 10 2006 019 170 and DE 29 52 10 19 described reflectors, and the usual in sailing ships so-called Topsets. However, these reflectors are not used in the context of data transmission.

From the JP 2005 17 42 37 A a device for car-to-car communication is known, in which the emitted from a transmitter of a first motor vehicle electromagnetic wave is received by a receiver of a second motor vehicle. The direction of reception is hereby aligned with the weakly bent wave, so that the communication can be improved.

From the DE 10 2007 042 792 A1 a method for environmental monitoring for a motor vehicle is known. This can use visibility-independent car-to-car communication based on radio. The reaction of the vehicle can be tuned to the behavior of other road users.

It is an object of the invention to provide an easy-to-implement method and a low-cost and low-maintenance system for visual connection-independent data transmission from a transmitter to a receiver in traffic.

This object is achieved by a method having the features of claim 1, and a system having the features of claim 5.

• Aussenden von elektromagnetischer Strahlung, in der Daten codiert sind, durch den Sender, welcher in einem Fahrzeug oder in einem Verkehrsinfrastrukturobjekt vorliegt;
• Bereitstellen einer Reflektorvorrichtung, welche dazu ausgebildet ist, die ausgesendete elektromagnetische Strahlung zumindest teilweise zu reflektieren;
• Anordnen der Reflektorvorrichtung, so dass die ausgesendete elektromagnetische Strahlung vom Empfänger empfangen werden kann; und
• Empfangen der elektromagnetischen Strahlung durch den Empfänger, welcher in einem Fahrzeug oder in einem Verkehrsinfrastrukturobjekt vorliegt.

The invention relates to a method for view-independent data transmission from a transmitter to a receiver in a car-to-car or car-to-infrastructure communication system, and comprising the following steps:

• Transmitting electromagnetic radiation in which data is encoded by the transmitter which is present in a vehicle or in a traffic infrastructure object;
• Providing a reflector device which is designed to at least partially reflect the emitted electromagnetic radiation;
• Arranging the reflector device so that the emitted electromagnetic radiation can be received by the receiver; and
• Receiving the electromagnetic radiation by the receiver, which is present in a vehicle or in a traffic infrastructure object.

The car-to-car or car-to-infrastructure communication system can be distinguished, in particular, by the fact that a motor vehicle acquires its own driving data (speed, direction of movement, position, etc.) and this data is recorded via radio to other road users, for example, motor vehicles and / or traffic infrastructure objects (Traffic signal, traffic information display unit, traffic control center, etc.). The electromagnetic radiation may in particular be radio waves (eg WLAN, UMTS, etc.). The data which are encoded in the electromagnetic radiation may in particular be data relating to driving information of the vehicle in which the transmitter is present. The reflector device can in particular be designed such that it has a very high reflection coefficient for the respective frequency band of the electromagnetic radiation emitted by the transmitter. When arranging the reflector device, the desired reflection direction can be determined in particular via the laws of geometric optics from the main incident direction of the electromagnetic radiation emitted by the transmitter. In particular, transmitters and receivers in the respective vehicles can each also be operated as a receiver or transmitter

This method is particularly easy to implement or implement in road traffic. All that is required is to provide a suitable reflector device and attach and align it at a selected point. For the reflector device no own power supply is necessary, so that their operation can be done free of charge after a single installation. The very simple construction of the reflector device allows it to be little or no maintenance. An elaborate and maintenance-intensive active node, which acts as a receiver and re-transmitter, can be omitted. Still, a very reliable car-to-car or car-to-infrastructure communication ensured. The process is robust and not prone to error.

Preferably, the reflector device is arranged on a building flanking a traffic route. Alternatively or additionally, it may be provided that it is arranged on a traffic signal system, in particular a traffic light system. It can also be provided that the reflector device is placed in a curve or in the vicinity of a curve of a traffic route. Finally, it can also be provided that the reflector device is arranged in a junction of several traffic routes, in particular in the center of an intersection. These positions for the reflector device are particularly well suited to ensure easy, uncomplicated and reliable mounting while ensuring the reflection of electromagnetic radiation into areas in which the vehicle may potentially be with the receiver. In particular, no complex and additional equipment, such as posts, columns, etc., are required for the attachment, but the reflector device can be arranged on objects that are already present and possibly already serve for other purposes. Costly installations and redundancy are thereby avoided.

It is particularly preferred in this case if the reflector device is arranged at an intersection of a first and a second traffic route so that it reflects the emitted substantially in the direction of the first traffic route electromagnetic radiation substantially in the direction of the second traffic route. If the vehicle is located with the transmitter on the first traffic route and the vehicle with the receiver on the second traffic route, it may not be ensured on the basis of the intersection of the two traffic routes that there is a line of sight connection between transmitter and receiver. For example, this may be interrupted by a building flanking the traffic routes between the first and the second traffic route. Then, the reflector device still allows car-to-car communication between the transmitter and receiver of the two vehicles, since the reflector device is arranged at the intersection of the two traffic routes. The beam angle of the electromagnetic radiation emitted by the transmitter can be suitably changed by the reflector so that the electromagnetic radiation is redirected to the receiver. For this purpose, the reflector can in particular have a strong preferred direction. Preferably the reflector be designed and arranged so that the angle between incident and reflected electromagnetic radiation is 90 °. This embodiment is particularly advantageous at intersections, the traffic routes intersect at 90 ° angle, the reflector device is then particularly preferably mounted in the middle of the intersection.

Preferably, the electromagnetic radiation has a frequency in the range of 4 GHz to 7 GHz, and in particular a frequency in the range 5.8 GHz to 6 GHz. Particularly preferred here is a frequency of 5.85 GHz to 5.925 GHz. This range corresponds to the Dedicated Short Range Communication (DSRC) frequency band, which results from the standard IEEE 802.11p. For the electromagnetic radiation, however, all other arbitrary frequencies can be provided within the frequency bands, which are defined in the standard IEEE 802.11 or IEEE 802.11p. The frequency of the electromagnetic radiation used in the method is then optimally adapted to the frequency bands usually used in car-to-car or car-to-infrastructure communication systems.

The system according to the invention serves for the visual connection-independent data transmission from a transmitter to a receiver in traffic. It comprises a transmitter, which is designed to emit electromagnetic radiation in which data is coded and which is present in a vehicle or in a traffic infrastructure object. It also comprises a receiver which is adapted to receive the electromagnetic radiation and which is present in a vehicle or in a traffic infrastructure object. Finally, it also includes a reflector device, which is designed to at least partially reflect the emitted electromagnetic radiation, and which can be arranged so that the emitted electromagnetic radiation can be received by the receiver.

Preferably, the reflector device comprises at least one planar reflector element made of metal, which may be in particular a sheet metal. The reflector device can then be produced very inexpensively, for example, by welding the sheets. This embodiment is extremely robust, mechanically stable, low-maintenance, weather-resistant, low error prone and at the same time guarantees a very effective reflection of electromagnetic radiation.

Preferably, the reflector device comprises at least three reflector elements, which are arranged to each other so that they form outer sides of a pyramid or a cube. The pyramid or the cube can then be arranged in particular with respect to perpendicular traffic routes so that at the intersection of the traffic routes have edges of the pyramid or the cube in the direction of the traffic routes. This embodiment of the reflector device is particularly suitable for mounting at the intersection of road intersections or T-intersections. The shape of the reflector device can also be derived from that of a pyramid, in that the reflector elements are configured convexly curved. Then the incident electromagnetic radiation can be reflected in many different directions.

The preferred embodiments presented with reference to the method according to the invention and their advantages apply correspondingly to the system according to the invention.

Fig. 1

eine schematische Aufsicht auf eine Straßenkreuzung mit Fahrzeugen, die über eine Car-to-Car Kommunikation mitein-ander in Verbindung stehen;

Fig. 2

eine perspektivische Ansicht einer Straßenflucht;

Fig. 3A

ein erstes Ausführungsbeispiel für eine mögliche Anbringung einer Reflektorvorrichtung;

Fig. 3B

ein zweites Ausführungsbeispiel für eine mögliche Anbringung einer Reflektorvorrichtung;

Fig. 3C

ein drittes Ausführungsbeispiel für eine mögliche Anbringung einer Reflektorvorrichtung; und

Fig. 4

ein Ausführungsbeispiel für eine Reflektorvorrichtung.

Reference to exemplary embodiments, the invention is explained in more detail below. Show it:

Fig. 1

a schematic plan view of a road intersection with vehicles that communicate with each other via a car-to-car communication;

Fig. 2

a perspective view of a street escape;

Fig. 3A

a first embodiment of a possible attachment of a reflector device;

Fig. 3B

a second embodiment for a possible attachment of a reflector device;

Fig. 3C

a third embodiment for a possible attachment of a reflector device; and

Fig. 4

an embodiment of a reflector device.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

Fig. 1 shows in plan two roads 2a and 2b, which meet at a road junction 3 perpendicular. The streets 2a and 2b are flanked on all sides by adjacent buildings. The buildings 5a, 5b, 5c and 5d complicate or prevent a direct line of sight between the road canyons formed by the roads 2a and 2b.

On the roads 2a and 2b are a total of three carriages 1 a, 1 b and 1 c. Carts 1 a and 1 c drive in the opposite direction on the road 2a and are in direct line of sight with each other. In all of the vehicles 1 a to 1 c, electronic communication devices belonging to a car-to-car communication system are installed. These devices can serve both as a transmitter and as a receiver for radio frequency 5.8 GHz. For example, the motor vehicle 1a detects its current position and speed and transmits this data via a radio link to other road users. For this purpose, the car-to-car communication device is ready in the motor vehicle 1a, which can emit radio radiation as a transmitter S. A similar device is provided in the motor vehicle 1c, which serves as a receiver E1 for this electromagnetic radiation. Since there is a direct line of sight between the vehicles 1 a and 1 c, a direct transmission of the data via an electromagnetic radio beam R3 from the transmitter S to the receiver E1 is possible.

In contrast, there is no direct line of sight between the cars 1 a and 1 b. The transmitted by the transmitter S to a receiver E of the motor vehicle 1 b radio beam R4 can not reach the receiver E due to the building 5a. The direct line-of-sight propagation is interrupted by the building 5a. Just between the cars 1 a and 1 b, however, a data exchange on car-to-car communication would be particularly helpful, eg. B. to avoid a collision of the two carriages 1 a and 1 b at the intersection 3. According to the prior art, however, such a communication is not readily possible because the radio contact is interrupted by the building 5a.

In order nevertheless to enable the radio contact, a reflector device in the form of a reflector pyramid 4 is in the middle of the intersection 3, that is at the intersection of the streets 2a and 2b, attached. This reflector pyramid is constructed so that it has a square base. The pyramid forming side surfaces are formed by welded together metal sheets, which are able to reflect the electromagnetic radiation of 5.8 GHz particularly well.

As in Fig. 2 2, the reflector pyramid 4 is attached to a traffic light installation 6 in such a way that the tip of the pyramid points perpendicular to the road surface at the intersection of the roads 2a and 2b. The reflector pyramid 4 is in this case aligned so that two of its edges facing in the direction of the course of the road 2a and two of its edges in the direction of the course of the road 2b. The electromagnetic radiation emitted by the transmitter S in the beam direction R1 then impinges on the reflector pyramid 4 and is reflected there at an angle α in the direction of the road 2b. The reflected radio beam is denoted by R2. This beam R2 can now be easily received by the receiver E of the motor vehicle 1b. About the reflector pyramid 4 of the radio beam R1 is deflected so that it meets as a radio beam R2 to the receiver E, so that despite the lack of a line of sight, a car-to-car communication between the cars 1 a and 1b is possible. In particular, the reflector device is neither aligned nor designed such that it sends back the electromagnetic waves in the direction of irradiation (as in the top set), nor evenly distributes them in space.

The Figs. 3A to 3C show further possible road constellations and arrangements of a reflector device. The reflector device is formed in these embodiments as a reflector cube, wherein in the FIGS. 3A to 3C Cube surfaces shown in plan must not necessarily be formed of reflective material. However, the vertical cube side surfaces are again made of metal sheets welded together. In Fig. 3A the intersection 3 is formed as a T-junction of two roads 2c and 2d. Direct radio communication between transmitter S and receiver E is prevented by a building 5. However, the reflector cube 7 is aligned at the T-crossing point so that, according to the laws of geometric optics, the radio beam R1 emitted by the transmitter S can reach the receiver E as a reflected radio-ray R2. A car-to-car communication is thereby made possible.

Fig. 3B shows a curve 8 between the streets 2c and 2d, in turn, a building 5 prevents the direct radio communication between transmitter S and receiver E. The reflector cube 7 is now mounted in the curve 8 on the flanking building 5e and in turn allows a 90 ° reflection of the incoming electromagnetic radiation, ie the rays R1 and R2 are perpendicular to each other.

Fig. 3C shows a situation in which the roads 2c and 2d do not intersect at right angles to the intersection 3. By suitable attachment of the reflector cube 7, however, a geometrical situation can again be established which allows the electromagnetic beam R1 emitted by the transmitter S to reach the receiver E as a ray R2 by reflection on the reflector cube 7. It can be seen that the invention improves car-to-car communication, especially in the area of intersections in densely built-up areas.

Fig. 4 shows a further possible embodiment of a reflector device 9, which comprises four convex curved reflector elements 10. As can be seen from the figure, then not only a reflection of the incident rays R1 in the horizontal direction, but also in the vertical direction takes place. Is this reflector device 9 as well as the reflector pyramid 4 in Fig. 1 and 2 attached to a traffic light system, it is ensured that the motor vehicle 1b can receive the electromagnetic radiation R2 both very well when he is far away from the traffic light system 6 or is very close to her. In particular, a very good reception is ensured even when the motor vehicle 1b is already almost below the reflector device 9 on the intersection 3.

Claims (7)

A method for view-independent data transmission from a transmitter (S) to a receiver (E) in a car-to-car or car-to-infrastructure communication system, characterized by the steps of: Emitting electromagnetic radiation (R1) in which data is coded by the transmitter (S) present in a vehicle (1a) or in a traffic infrastructure object (6); - Providing a reflector device (4, 7, 9) which is adapted to at least partially reflect the emitted electromagnetic radiation (R1) (R2); Arranging the reflector device (4, 7, 9) so that the emitted electromagnetic radiation (R1, R2) can be received by the receiver (E); and - Receiving the electromagnetic radiation (R2) by the receiver (E), which is present in a vehicle (1 b) or in a traffic infrastructure object (6). Method according to claim 1,
characterized in that
the reflector device (4, 7, 9) on a building (5, 5a, 5b, 5c, 5d, 5e) flanking a traffic route (2a, 2b, 2c, 2d) and / or on a traffic signal system (6) and / or in a curve (8) of a traffic route (2c, 2d) and / or in a junction (3) of several traffic routes (2a, 2b, 2c, 2d) is arranged. Method according to claim 1 or 2,
characterized in that
the reflector device (4, 7, 9) is arranged at an intersection (3) of a first (2a; 2c) and a second traffic route (2b; 2d) so as to be substantially in the direction (R1) of the first traffic route (2a , 2c) emits emitted electromagnetic radiation substantially in the direction (R2) of the second traffic route (2b, 2d). Method according to one of the preceding claims,
characterized in that
the electromagnetic radiation (R1, R2, R3, R4) has a frequency in the range 4 to 7 GHz, preferably 5.8 to 6 GHz, particularly preferably 5.85 to 5.925 GHz. A system for visible connection-independent data transmission from a transmitter (S) to a receiver (E) in traffic with a transmitter (S), which is adapted to emit electromagnetic radiation (R1) in which data is coded and which in a vehicle (1a ) or in a traffic infrastructure object (6) and with a receiver (E) which is designed to receive the electromagnetic radiation (R1, R2) and which is present in a vehicle (1b) or in a traffic infrastructure object (6) , characterized by
a reflector device (4, 7, 9), which is designed to at least partially reflect the emitted electromagnetic radiation (R1) (R2), and which can be arranged so that the emitted electromagnetic radiation (R1, R2) from the receiver (E ) can be received. System according to claim 5,
characterized in that
the reflector device (4, 7, 9) comprises at least one planar reflector element made of metal, in particular sheet metal. System according to claim 5 or 6,
characterized in that
the reflector device (4, 7, 9) comprises at least three reflector elements (10), which are arranged to one another such that they form outer sides of a pyramid (4, 9) or a cube (7).

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