Operation of a communication device of a motor vehicle

Abstract

The invention relates to a method for operating a communication device (32, 34) of a motor vehicle (14), in which the communication device (32, 34) communicates at least with at least one further motor vehicle (16) or at least one static counterpart station (12), for which purpose a wireless communication connection (20, 22, 24) based on linearly polarized electromagnetic waves is used. For use of the communication connection (20, 22, 24), a transmission signal is emitted by the communication device (32, 34) at a preset transmission power, wherein the transmission power is reduced in dependence on a reception by the communication device (32, 34) of a reception signal which uses electromagnetic waves which are at least partially polarized orthogonally to the linearly polarized electromagnetic waves.

Description

Technical Field

[0001] This invention relates to a method for a communication device used in a motor vehicle, wherein the communication device communicates with at least one other motor vehicle or at least one static counterpart station / communication counterpart. For this purpose, a wireless communication connection based on linearly polarized electromagnetic waves is used, wherein the communication device transmits a signal at a preset transmission power to use the communication connection. Furthermore, this invention relates to a communication device arranged in a motor vehicle, wherein the communication device is configured to communicate with at least one other motor vehicle or at least one static counterpart station. For this purpose, a wireless communication connection based on linearly polarized electromagnetic waves is used, wherein the communication device is configured to transmit a signal at a preset transmission power to use the communication connection. Finally, this invention also relates to a motor vehicle having a communication device for communicating with at least one other motor vehicle or at least one static counterpart station. Background Technology

[0002] Such communication devices, especially radio-based communication devices, are known in the prior art. They are sometimes also referred to as active antenna units or similar. These communication devices are particularly used to enable communication between vehicles and also between static counterparts, such as infrastructure, including traffic lights, traffic signs, and / or similar objects, especially roadside units (RSUs). This enables transportation networking. For example, transportation networking can include networking of communication technologies between motor vehicles and between motor vehicles and infrastructure. This type of transportation networking is also called Vehicle-to-Everything (V2X) or similar names. Furthermore, there are transportation networks between vehicles (V2V), between vehicles and roads (V2R), between vehicles and infrastructure (V2I), between vehicles and networks (V2N), between vehicles and people (V2P), and so on. Traffic networks should improve traffic safety, increase traffic efficiency, and achieve energy savings. Furthermore, traffic networks are used to, at least partially, enable autonomous driving.

[0003] Traffic networking systems or information service systems can be, for example, CV2X. Here, cellular networks are involved, enabling communication between vehicles (PC5) and between vehicles and infrastructure (Uu). For example, such information service systems operate in a frequency range of approximately 5.905 GHz to approximately 5.925 GHz. For this purpose, vehicles typically include corresponding communication devices that enable networking within the scope of the information service system. The communication devices are typically coupled to a controller in the vehicle, which communicates with other vehicles and / or infrastructure via the communication devices. The controller can, for example, provide vehicle data of its own vehicle to other vehicles and / or infrastructure. Similarly, the controller can obtain data from other vehicles and / or infrastructure for use, for example, in guiding the vehicle.

[0004] In addition, a known toll collection system, also known as ETC, provides wireless toll collection for motor vehicles. This wireless toll collection system uses radio-based communication, which utilizes electromagnetic waves at a frequency of approximately 5.8 GHz, such as those found in Toll Collect. TM The company's fee-based testing system.

[0005] Interference may occur when the aforementioned information service system and the aforementioned toll detection system are used in combination due to overlapping frequency ranges or excessively small frequency intervals. In particular, when a vehicle passes through a toll station, communication between the vehicle, especially the On-Board Unit (OBU) used for toll detection (ETC-OBU), and the toll station may be interfered with, thus denying passage at the toll station. This may be caused by the information service system emitting a high-power transmission signal, preventing the toll station from receiving or acquiring the corresponding signal from the On-Board Unit (OBU) used for toll detection. For this reason, for example, in Europe, regulations deactivate the information service system on the vehicle side in the area of ​​the corresponding toll station to allow passage without interfering with communication between the toll station and the ETC-OBU. Once past the toll station, the information service system is reactivated. For this purpose, the information service system is provided with the corresponding location data of the toll station in the vehicle, and this location data is compared with the vehicle's corresponding current location.

[0006] However, if the location data of the toll station is unavailable, the above method cannot guarantee the reliable functioning of the toll detection system. To improve this situation, for example, JP 4944719 B2 proposes an antenna unit with different antenna elements for the information service system and the toll detection system, which can reduce interference between them. In this regard, although improvements can be achieved on the vehicle side, the problem remains that the toll station may be interfered with by the transmitted signals of the communication device, making it impossible to guarantee normal toll detection function. In addition, US 2010 / 0304680A1 discloses a method and apparatus for reducing interference of signals in the main coverage area by utilizing transmit polarization. Summary of the Invention

[0007] Therefore, the object of the present invention is to improve the communication device in such a way that interference that may be caused at toll booths due to the transmission signals emitted by the communication device can be reduced.

[0008] As a solution, the present invention proposes the method, communication device, and motor vehicle according to the independent claims.

[0009] Advantageous improvements are obtained through the features described in the dependent claims.

[0010] In particular, the present invention proposes to reduce transmission power by receiving a received signal through a communication device, the received signal being an electromagnetic wave that is at least partially orthogonal to linearly polarized electromagnetic waves.

[0011] In particular, it is proposed that the communication device is configured to reduce the transmission power according to the reception of a received signal, which uses an electromagnetic wave that is at least partially orthogonal to linearly polarized electromagnetic waves.

[0012] In particular, it is proposed that the communication device be constructed according to the present invention in relation to such motor vehicles.

[0013] The present invention is based on the idea that once a toll station is within the effective communication range, it can be identified by the communication device, thereby reducing the transmission power of the transmitted signal. By intentionally reducing the transmission power, it is possible to avoid interfering with the toll station when receiving the corresponding communication signal from the ETC-OBU, thus ensuring the toll detection function more reliably when passing through the toll station. Unlike in the prior art, neither the location data of the toll station nor the location data of the vehicle are required for this purpose. Instead, the communication device, preferably located in the vehicle, can be identified as being within the communication range of the toll station by evaluating the received signal. For this purpose, the corresponding received signal is evaluated by the communication device. Here, the present invention particularly utilizes the fact that information service systems typically use linearly polarized, especially vertically polarized, electromagnetic waves to achieve communication connections. In contrast, communication connections for toll detection typically use circularly polarized electromagnetic waves. Therefore, the communication connection of the toll detection system or toll station uses electromagnetic waves that are at least partially horizontally polarized. This can be determined by the correspondingly constructed communication device.

[0014] Therefore, the communication device, especially its receiving unit, can have a corresponding antenna element that can separately receive linearly polarized, especially vertically polarized, electromagnetic waves and electromagnetic waves orthogonally polarized, especially horizontally polarized, electromagnetic waves. Thus, by evaluating the electrical signal provided by the antenna element correspondingly matched to the horizontally polarized electromagnetic waves, it can be determined whether the toll station is within the effective communication range. Once the toll station is determined to be within the effective communication range, the transmission power of the transmission signal of the communication device used for CV2X communication can be reduced accordingly, thereby preferably ensuring that the communication connection with the toll station is substantially completely free from interference.

[0015] Reducing the transmission power can include reducing it in a matched / adjusted manner, thereby reliably establishing a communication connection between the ETC-OBU on the vehicle side and the toll station. However, reducing the transmission power can also include disabling the transmitter of the communication device. Therefore, it is generally possible that, with the communication device according to the invention, the function of the communication device in transmitting signals can be adjusted independently of any location data, enabling communication between the toll station and the ETC-OBU to be achieved substantially without interference. Therefore, it is not necessary to constantly maintain the availability of a database with the corresponding toll station data.

[0016] To enable communication within the scope of an information service system, the communication device may include a high-frequency circuit assembly suitable for demodulating and / or decoding antenna signals provided by the antenna unit, and, if necessary, providing them to the vehicle's controller via attenuation circuits, filtering circuits, and / or the like. Conversely, the communication device may be used to transmit controller data, for example, via filtering circuits and / or attenuation circuits, to the high-frequency circuit assembly so that a corresponding high-frequency signal can be transmitted to the antenna unit. For this purpose, the high-frequency circuit assembly may be connected to a power measurement unit or power measurement circuit, by means of which the received power of the antenna signal can be determined, for example. By means of a control unit (to which the power measurement unit or power measurement circuit is connected), the transmit power of the transmitted signal to be transmitted can be determined and / or adjusted. The power measurement circuit may be connected to the control unit in terms of communication technology or signal technology. For this purpose, the control unit is connected to an attenuation circuit, which can be adjusted by the control unit in a suitable manner. The above-mentioned components are preferably integral parts of the communication device. Therefore, the communication device is used to establish a communication connection between the controller on the vehicle side and at least one other vehicle or at least one static counterpart station to enable the desired traffic network.

[0017] Preferably, the communication device also includes the aforementioned antenna unit. The high-frequency circuitry is preferably connected in signal technology to the antenna element of the antenna unit, the antenna element being used to emit and / or receive linearly polarized, especially vertically polarized, electromagnetic waves.

[0018] The antenna unit also has an antenna element for receiving horizontally polarized electromagnetic waves. This antenna element is preferably connected to a power combiner, to which another antenna element is also connected. The power combiner combines the antenna signals from the two antenna elements and provides the power signal to another power measurement unit or another power measurement circuit that determines the power of the combined signal from the power combiner. The power determined in this way is provided to the control unit and evaluated by the control unit. Since this power is particularly relevant to horizontally polarized electromagnetic waves, it can be determined whether horizontally polarized electromagnetic waves have been received. This serves as an indicator of whether the toll station is within the effective communication range. That is, the control unit can determine whether the toll station is within the effective communication range and, when this type of toll station is detected within the effective communication range, accordingly reduce the transmission power. This can be achieved by the control unit through corresponding control of the attenuation circuit.

[0019] Therefore, the present invention does not respond in terms of reception on the communication device side or the vehicle side, but rather influences the transmission power of the transmitted signal based on the reception of the received signal. This makes it possible to influence the function of the toll station through the communication device, thereby improving or enabling reliable communication between the toll station and the ETC-OBU.

[0020] The transmission signal can be emitted by the communication device at the beginning of establishing a communication connection. Alternatively, the transmission signal can be emitted at a later time during the duration of the communication connection. Finally, it is also possible for more than one transmission signal to be emitted by the communication device during the communication connection. The communication connection is not limited to the emission of transmission signals. Preferably, the communication connection also includes the reception of received signals. Thus, a bidirectional communication connection can be established between the communication device and another vehicle or stationary counterpart. However, in principle, the communication connection can also be unidirectional and configured solely for emitting one or more transmission signals. However, the invention is not limited to this. Nevertheless, the invention stipulates that even in the aforementioned unidirectional communication connection, the method according to the invention can be configured to minimize interference with the toll station's receiving unit, for example, when receiving the transmission signal from the ETC-OBU.

[0021] For example, the present invention can be used in a frequency range of approximately 1 GHz to approximately 20 GHz. However, the present invention is not limited to this frequency range. The present invention can also be applied to situations where similar communication effects may occur due to interference from transmitted signals with external receiving stations.

[0022] Furthermore, when the received power of the received signal exceeds a preset comparison value, the transmit power is reduced. This has the advantage that the transmit power does not need to be reduced for all received power levels. Preferably, intervention is only performed when a significant received power for the horizontally polarized electromagnetic wave is determined. Thus, a significance criterion can be defined by a preset comparison value, which is used to ensure that communication conducted through the communication connection can operate without interference for as long as possible. Therefore, this comparison value can be determined and preset based on empirical, previously performed functional measurements.

[0023] Furthermore, it is proposed to reduce the transmit power value based on the received signal power value. This allows for a separate response to the current situation within the current communication via the communication connection. It is understood that when the distance between the toll station and the vehicle is large, a relatively small reduction in transmit power is sufficient to maintain reliable communication between the toll station and the ETC-OBU. However, as the vehicle approaches the toll station, the transmit signal power affects the toll station's receiving unit and may cause interference. Therefore, it is entirely possible to determine, for example, the degree to which the transmit power should be reduced to maintain the communication connection between the toll station and the ETC-OBU, based on the received power. Furthermore, this design has the advantage of not requiring interruption of the communication connection. Depending on the spatial conditions, continuous use of the communication connection can even be maintained entirely.

[0024] Linearly polarized electromagnetic waves are vertically polarized electromagnetic waves, and orthogonally polarized electromagnetic waves are at least partially horizontally polarized electromagnetic waves. The horizontal received power of the horizontal received signal component and the vertical received power of the vertical received signal component are acquired and evaluated to determine the received power. Preferably, the received signal components are acquired independently of each other, for example, by means of antenna elements correspondingly constructed of antenna elements. For this purpose, the antenna elements can be correspondingly constructed and / or oriented for receiving the corresponding polarization of the received signal component. This achieves not only the acquisition of the horizontal received signal component substantially independently, for the purpose of identifying and distinguishing, for example, horizontally polarized or circularly polarized electromagnetic waves, but also, in the case of correspondingly additional evaluation of the vertical received signal component, the determination of whether a circularly polarized received signal exists. Thus, the invention can be applied, especially when there is a communication connection between the ETC-OBU and the toll station, for example, based on circularly polarized electromagnetic waves.

[0025] Furthermore, the phase of the horizontally received signal component is adjusted. This allows for compensation for potential runtime differences arising from the acquisition and / or evaluation of the received signal component via the communication device, thereby improving reliable functionality.

[0026] Furthermore, it is proposed that received power be generated from horizontal and vertical received power using a power combiner. This allows for the determination of the actual received power, particularly when receiving signals using circularly polarized electromagnetic waves. This further improves the functionality of the communication device. Moreover, the power combiner simplifies the determination of the received signal power, enabling the provision of control signals, for example, those derived therefrom, to the control unit of the communication device. Consequently, the control unit can readily control the high-frequency circuit components and / or attenuation circuits to ensure, preferably continuously, reliable communication between the toll station and the ETC-OBU. Furthermore, the transient distance between the vehicle and the toll station can be fully deduced from the received power. This can be used for other functionalities of the invention and / or for higher-level vehicle control devices, particularly controllers.

[0027] It is determined whether the received signal uses circularly polarized electromagnetic waves. For this purpose, the vertical and horizontal received signal components can be evaluated, particularly the horizontal and vertical received power. By considering the horizontal received power, it can be determined whether the vertical signal component includes a portion caused by circularly polarized electromagnetic waves, in addition to the portion caused by only vertically polarized electromagnetic waves. Therefore, through appropriate evaluation, it can be determined whether the received signal uses circularly polarized electromagnetic waves. This is particularly suitable for toll stations that use circularly polarized electromagnetic waves for communication with the ETC-OBU. This allows for a good distinction between the toll station signal and the communication connection signal of the communication device, which essentially uses only vertically polarized electromagnetic waves. Preferably, the evaluation can be performed by a control unit. However, it is also generally possible to at least partially implement the corresponding hardware circuitry for this evaluation.

[0028] Regarding the communication device, it is proposed that the device be configured to be technically connected to the controller of a wireless toll collection detection system, particularly an ETC-OBU, which can be deployed in a motor vehicle, and to establish a communication connection using the antenna unit of the controller. The advantage of this design is that the communication device does not require a separate antenna unit. By means of the method according to the invention, the communication device and the ETC-OBU can establish their respective communication connection almost without interference, thereby achieving the corresponding reliable functions. This reduces the complexity of the communication device.

[0029] Therefore, the interference problem can be solved by the present invention, thereby enabling the coexistence of the two systems with virtually no interference. By preferably integrating additional detection circuitry for horizontally polarized electromagnetic waves, particularly circularly polarized electromagnetic waves, from the toll collection system into the communication device or CV2X compensator, the present invention enables the communication device to detect, in particular, the circularly polarized received signal from the toll station and adjust the amplification of its own transmitted signal, thus minimizing critical interference between the toll collection system and the CV2X infrastructure. For example, in China, the coexistence problem between the CV2X system and the toll collection system, especially the ETC toll collection system, can be solved. Complex and costly measures are not required regarding the communication device and existing infrastructure, especially in the toll collection system, preferably in the RSU and ETC-OBU. Furthermore, no corresponding filters are needed to ensure coexistence. The detection circuitry according to the present invention can be integrated into the communication device in a simple manner.

[0030] The present invention also includes a communication device for a motor vehicle. The communication device, particularly a control unit, may have a data processing apparatus or a processor device, which is at least partially included in the control unit of the communication device and configured to perform embodiments of the method according to the invention. For this purpose, the processor device may have at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (Field Programmable Gate Array) and / or at least one DSP (Digital Signal Processor). Furthermore, the processor device may have program code configured to perform embodiments of the method according to the invention when executed by the processor device. The program code may be stored in the data memory of the processor device.

[0031] This invention also includes improvements to the communication device according to the invention, which have features already described in conjunction with improvements to the method according to the invention. For this reason, corresponding improvements to the communication device according to the invention will not be described again here.

[0032] The motor vehicle according to the invention is preferably designed as an automobile, especially a passenger car or a truck, or a bus or motorcycle.

[0033] The present invention also includes combinations of features of the described embodiments. Attached Figure Description

[0034] The embodiments of the present invention will be described below. Wherein:

[0035] Figure 1 A schematic perspective view shows three vehicles and one RSU in a traffic networking system;

[0036] Figure 2 A schematic top view is shown Figure 1 One of the motor vehicles in the system, which has a communication device for the traffic network system and an ETC-OBU for the toll detection system;

[0037] Figure 3 The electric field vector of a linearly vertically polarized electromagnetic wave is illustrated in a schematic diagram.

[0038] Figure 4 The diagram illustrates the use of block diagrams based on... Figure 2 Communication devices used in transportation networking systems;

[0039] Figure 5 The schematic perspective view shows a toll station of a toll detection system on a four-lane road, as well as the radio connection range of the toll station's transmitter / receiver unit for acquiring ETC-OBUs for passing motor vehicles;

[0040] Figure 6 A schematic top view shows the situation according to... Figure 5 toll booths;

[0041] Figure 7 The electric field vector of a left-handed circularly polarized electromagnetic wave is illustrated in a schematic diagram.

[0042] Figure 8 A schematic side view shows the situation according to... Figure 5 A partial view of the toll station, showing the communication range of the toll station's transmitting / receiving devices;

[0043] Figure 9 The coexistence analysis of CV2X and ETC based on the corresponding available spectrum is illustrated in the diagram.

[0044] Figure 10 The diagram illustrates the use of block diagrams based on... Figure 4 A communication device having a first design of a supplementary detection circuit for detecting circularly polarized electromagnetic waves;

[0045] Figure 11 The diagram illustrates the use of block diagrams based on... Figure 4 A communication device having a second design scheme for a supplementary detection circuit for detecting circularly polarized electromagnetic waves; and

[0046] Figure 12 The diagram illustrates the use of block diagrams based on... Figure 4 The communication device has a third design scheme with a supplementary detection circuit for detecting circularly polarized electromagnetic waves. Detailed Implementation

[0047] The embodiments described below are preferred embodiments of the present invention. Each part of the embodiments described in the embodiments represents a separate, independent feature of the invention, which also independently improves the invention. Therefore, the disclosure should also include combinations of features different from those of the illustrated embodiments. Furthermore, the described embodiments can also be supplemented by other features already described in the present invention.

[0048] In the figure, the same reference numerals represent elements with the same function.

[0049] Figure 1 The diagram illustrates a traffic network system 10 and three vehicles 14, 16, and 18 traveling on road 26. An RSU 12, acting as a static counterpart, is fixedly positioned beside road 26. Each of vehicles 14, 16, and 18 is equipped with a controller and a CV2X-OBU 30 with communication devices 32 and 34. Figure 2 , 4 Each of motor vehicles 14, 16, and 18 can communicate with the corresponding other motor vehicle among 14, 16, and 18 via a communication device, or alternatively or supplementarily with the static counterpart station 12. For this purpose, corresponding wireless communication connections 20, 22, and 24 based on vertically polarized electromagnetic waves are used.

[0050] The traffic network system 10 is configured as a CV2X-based information service system. The traffic network system is a cellular network that enables communication between vehicles (PC5) and between the corresponding infrastructure in motor vehicles 14, 16, and 18, and in this RSU 12. Figure 1 Communication connections 20 and 22 (Uu) are specified in this document. In this case, the frequency range used for communication connections 20, 22, and 24 covers from approximately 5.905 GHz to approximately 5.925 GHz. This frequency range is preferably customized according to the requirements of the automotive application. Communication connection 24 is the communication connection between vehicle 14 and vehicle 16.

[0051] When using communication connections 20, 22, and 24, the CV2X-OBU 30 provides the transmission signal, which is then transmitted at a preset transmission power by means of communication devices 32 and 34.

[0052] Here, the traffic network system 10 is configured as an information service system based on CV2X. The traffic network system is a cellular network that enables communication between vehicles (PC5) and between the respective vehicles and the corresponding infrastructure, in this case, RSU 12. Figure 1Communication connections 20 and 22 (Uu) are specified in this document. In this case, the frequency range used for communication connections 20, 22, and 24 covers from approximately 5.905 GHz to approximately 5.925 GHz. This frequency range is preferably customized according to the requirements of the automotive application. Communication connection 24 is the communication connection between vehicle 14 and vehicle 16.

[0053] Figure 2 A schematic top view shows the situation according to... Figure 1 One of the motor vehicles, specifically motor vehicle 14 in this case. The other two motor vehicles 16 and 18 are constructed in a substantially similar manner. However, depending on their construction, the motor vehicles can also be constructed differently from each other.

[0054] The vehicle 14 has a controller 30, hereinafter also referred to as a CV2X-OBU. The controller 30 is connected to corresponding active antenna units or communication devices 32 and 34 via corresponding antenna wires 36 and 38. Through the communication devices 32 and 34, the controller 30 can both transmit and receive radio signals. Thus, communication connections 20, 22, and 24 can be achieved. For reliable communication, the communication device 32 is arranged as a CV2X antenna unit with a compensator on the roof of the vehicle 14. Here, another communication device 34 is arranged in the rearview mirror base below the windshield of the vehicle 14.

[0055] Furthermore, it can be seen that the CV2X-OBU 28, which is the toll detection system 68, is located in the upper area of ​​the windshield. Figure 5 Part of the system. Toll detection system 68 is a satellite-assisted toll detection system used to determine tolls based on the use of road 26.

[0056] To improve the overall performance of the traffic networking system 10 or CV2X system in the motor vehicle 14, it is specified that the attenuation of the antenna wires 36 and 38 be eliminated or at least partially compensated. Active antenna elements or communication devices 32 and 34, also referred to as CV2X compensators, are used for this purpose. The CV2X compensators here amplify the corresponding signals not only during transmission but also during reception. Vertically polarized electromagnetic waves are used together for the communication connections 20, 22, and 24. During transmission and reception, the amplification achieved by the communication devices 32 and 34 can be adjusted independently of each other. Typically, for transmission, a maximum transmission power of approximately 23 dBm is sought at the base point of the corresponding antenna element of the communication devices 32 and 34. The communication devices 32 and 34 each have at least one corresponding antenna element, by which the transmission and reception of vertically polarized electromagnetic waves can be achieved.

[0057] Figure 3The electric field vector of a linearly vertically polarized electromagnetic wave is illustrated in a schematic graph via curve 34. The horizontal axis is associated with the propagation direction K. The vertical axis is assigned to the electromagnetic field intensity. The magnitude of the field intensity vector is expressed as E. V0 express.

[0058] Figure 4 A communication device, specifically active antenna elements 32 and 34, is illustrated schematically in block diagram form, for example, in a transportation network system 10. The communication devices 32 and 34 have antenna elements 40 configured to emit and / or receive vertically polarized electromagnetic waves. Antenna elements 40 are connected to a high-frequency circuit assembly 50, which provides corresponding electrical signals to antenna elements 40 during transmission operation.

[0059] During receiving operation, the high-frequency circuit assembly 50 provides corresponding amplification and processing of the received signal. The high-frequency circuit assembly 50 is also connected to an adjustable attenuation circuit 44. Attenuation can be adjusted using the adjustable attenuation circuit 44 according to corresponding control signals, not only during transmitting operation but also during receiving operation. The attenuation circuit 44 is also connected to a filter circuit 42. The filter circuit 42 is then itself connected to corresponding antenna wires in antenna wires 36 and 38, through which communication devices 32 and 34 are technically connected to the CV2X-OBU 30. Therefore, communication devices 32 and 34 are configured to be used for... Figure 3 The system transmits / receives signals and provides corresponding signals to the controller 30. Furthermore, corresponding signals can be provided here for transmission via communication devices 32 and 34.

[0060] Furthermore, the high-frequency circuit assembly 50 is connected to the power measurement circuit 48, by means of which the received power or transmitted power can be obtained. The power measurement circuit 48 is connected to the control unit 46 of the communication devices 32, 34, which is formed by a microcontroller. The control unit 46 provides control signals for the attenuation circuit 44, and therefore, the control unit 46 is connected to the attenuation circuit 44. In order to adjust the gain to a preset value, for example, about 15 dB, the attenuation circuit 44 can be adjusted accordingly by means of the control unit 46.

[0061] In principle, the traffic network system 10 must be able to integrate with toll collection and detection systems, such as those based on... Figure 5 The charging and testing system operates in a 68-way coexistence manner. For example, it can be seen from... Figure 2 As can be seen, vehicle 14 also includes the corresponding ETC-OBU 28, which is also part of the toll detection system 68. The ETC-OBU 28 here is basically in the form of a transponder or active antenna that should typically be located on the windshield of vehicles 14, 16, and 18.

[0062] Figure 5 A schematic perspective view shows the tollbooth 54 of the toll detection system 68 on a four-lane road 26, and the beamform radio connection range 58 of the transmitter / receiver 56 of the tollbooth 54. It is specified here that the corresponding radio connection range 58 is aligned with the corresponding lane of the four-lane road 26. Thus, wireless communication for toll detection can be implemented for each lane of the road 26. Figure 6 It shows according to Figure 5 A schematic top view of tollbooth 54. Figure 6 As shown, the radio connection range extends approximately 10 meters in the direction of travel ahead of toll plaza 54. Furthermore, the radio connection range 58 is correspondingly constructed over each lane of road 26 across its entire width.

[0063] When passing through toll station 54, ETC-OBU 28 communicates with toll station 54 via a communication connection within its corresponding radio connection range 58. Through this communication connection, the corresponding settlement process of toll detection system 68 is performed in the area also known as the toll zone. This requires, at least within the toll zone, that interference-free data exchange or interference-free communication between the corresponding ETC-OBU 28 and the corresponding transmitter / receiver 56 must be achieved.

[0064] To enable communication for the toll detection system 68, circularly polarized electromagnetic waves are used. The frequency range used here is approximately 5.8 GHz. Figure 7 Indicative, such as Figure 3 The graph shows the electric field vector of a left-handed circularly polarized electromagnetic wave, emitted by the transmitter / receiver 56 of the toll station 54, via curve 60. According to... Figure 5 A partial schematic side view of the toll plaza 54 shows typical characteristics of the corresponding antenna element of the transmitting / receiving device 56. An EIRP of approximately 33 dBm is achieved in the main fall direction. Figure 8 The main lobe of the antenna element of the transmitting / receiving device 56 covers the toll area.

[0065] According to Figure 7 In the case of left-hand circular polarization of the electromagnetic wave, the field intensity vector rotates left-hand in the direction of propagation K. Circular polarization can be achieved by feeding with a 90° phase shift and simultaneously offsetting the linearly polarized antenna elements by 90°. Here, the amplitudes of the two such linear components are essentially the same and are obtained as follows:

[0066]

[0067] E0 = E H0 =E VO

[0068] ω = 2πf;

[0069] In practical use, the toll detection system 68 must be able to operate simultaneously with the traffic network system 10. As can be seen above, interference or hindrance between the two systems may occur, at least within the toll area. The main reason is the small frequency interval between the available spectrum of CV2X and ETC, less than 100MHz. Therefore, it is assumed that, especially during reception, the transmitted signals of communication devices 32 and 34 may interfere with the transmitter / receiver device 56 of the toll station 54, thereby potentially interfering with the corresponding communication connection with the ETC-OBU 28. In this case, no suitable filtering device is available to achieve the corresponding decoupling or selection.

[0070] Figure 9 This illustrates the challenges of interference or coexistence. The schematic diagram shows the coexistence analysis of CV2X and ETC based on the corresponding available spectrum. Figure 9 The upper region shows a frequency band diagram, which indicates that the ETC uses the frequency range from 5.795 GHz to 5.815 GHz shown in the left region, while the CV2X uses the frequency range from 5.095 GHz to 5.925 GHz shown in the right region.

[0071] The diagram schematically illustrates the transmitting / receiving device 56 and communication devices 32 and 34, respectively, and schematically illustrates the filtering function of a universally applicable filter 66 at each of these devices. It can be seen that, despite the presence of filter 66, not only the transmitting / receiving device 56 but also the communication devices 32 and 34 can be loaded with significant signal components from other systems. This reveals the range within which interference or coexistence problems may occur. This range is within… Figure 9 The number 62 is used to represent the Chinese character.

[0072] Now, Figure 10 A schematic block diagram illustrates communication devices 32, 34, or corresponding active antenna elements according to a first design, which includes supplementary detection circuitry for detecting circularly polarized electromagnetic waves. This design is essentially based on... Figure 4 The design scheme is explained, and therefore, the relevant implementation scheme is provided as a supplementary reference.

[0073] According to Figure 4Unlike other designs, a detection circuit for circularly polarized electromagnetic waves is provided. This detection circuit includes an antenna unit 70 with two antenna elements (not shown). A first antenna element is used to transmit or receive vertically polarized electromagnetic waves, while a second antenna element is used to transmit and / or receive horizontally polarized electromagnetic waves. The first antenna element is connected to a first communication line 72, which is connected to a high-frequency circuit assembly 50 via a signal distributor 76. The second antenna element is connected to a power combiner 78 via a communication line 74. The power combiner is also connected to the signal distributor 76. Thus, the power combiner 78 is provided with horizontal received power for the horizontal received signal component and vertical received power for the vertical received signal (component). Through combination within the power combiner 78, these powers can be superimposed in a suitable manner.

[0074] The power combiner 78 is further connected to the power measurement circuit 80, which measures the superimposed received power and transmits the corresponding value to the control unit 46. This allows the value of the received power of the received signal to be determined, and this value can be used by the control unit 46 to adjust the attenuation circuit 44 such that the transmit power is reduced according to the value of the received power of the received signal. Preferably, this adjustment is chosen so that communication between the transmitting / receiving device 56 and the ETC-OBU 28 can be achieved without interference. For this purpose, for example, corresponding parameters or tabular values ​​can be provided, which allows the value for the transmit power to be determined based on the value of the received power. This reduces or even eliminates interference problems. The aforementioned components of the detection circuit can be at least partially integrated into the communication devices 32, 34.

[0075] That is, the scheme proposes that the detection circuit can detect and evaluate the circularly polarized signal of the toll station 54. For this purpose, the antenna element 70 has a dual-polarized passive antenna element that achieves sufficient polarization decoupling. Here, a relative bandwidth of 4% to 5% is achieved not only for the toll detection system 68 but also for the traffic networking system 10. The antenna element 70 supports linear vertical polarization and linear horizontal polarization. The received signal in the CV2X aspect is received through the antenna element of the antenna element 70, which is configured for vertical polarization. The received signal (as per...) Figure 4 As explained, the signal is amplified and transmitted to the controller 30 via the corresponding antenna wires 36, 38. During transmission, the CV2X signal provided by the controller 30 is transmitted to the communication devices 32, 34 via the antenna wires 36, 38, where it is amplified in a suitable manner and transmitted through the antenna elements of the antenna unit 70 configured for vertical polarization.

[0076] Conversely, the signal from the toll detection system 68 is received by the two antenna elements of the antenna unit 70. A structural superposition of the horizontal and vertical components of the received signal can be achieved, for example, by a power combiner 78 formed by an adapter circuit. This is done in a phase-corrected manner. Subsequently, the power measurement circuit 80 determines the received power of the signal, which is here a circularly polarized signal from the transmitting / receiving device 56. Based on the value of the received power, the control unit 46 adjusts the attenuation circuit 44. Thus, when the received signal at least partially uses horizontally polarized electromagnetic waves, the transmission power is reduced by the communication device according to the received signal.

[0077] Figure 11 With Figure 10 Another illustrative block diagram illustrates a second design scheme, which is based on... Figure 10 And according to Figure 4 The first design scheme is used; therefore, the following explanation only addresses the... Figure 10 The difference.

[0078] According to Figure 10 Unlike the first design scheme, according to Figure 11 The second design incorporates an adjustable phase-shifting circuit 82 in the detection circuit, the phase shift of which can be adjusted via control signals from the control unit 46. For this purpose, the phase-shifting circuit 82 is connected to the control unit 46. The phase-shifting circuit 82 is connected in the communication line 74 between the antenna unit 70 and the power combiner 78. Thus, the phase of the horizontal polarization component of the received signal can be shifted according to the corresponding control signals from the control unit 46. This achieves a dynamic change in the horizontal polarization component of the ETC signal. Consequently, through constructive interference, the maximum value of the received power of the received signal can be detected by the power combiner 78 using the power measurement circuit 80. In the case of destructive interference, destructive interference can be achieved by the power combiner 78, so the power measurement circuit 80 essentially cannot measure the power. By supplementing the phase-shifting circuit 82, the overall robustness of the detection circuit can be further improved.

[0079] Figure 12 A schematic block diagram of another communication device according to a third design scheme is shown, which is also based on... Figure 10 The first design scheme, therefore, is hereby supplemented for reference. Figure 10 as well as Figure 4 The implementation plan. The following will only explain the related... Figure 11 The difference.

[0080] According to Figure 11 The second design scheme differs from the first, replacing the power combiner 78, according to... Figure 12The detection circuit of the design includes two power measurement circuits 64 and 80, each independently connected to the control unit 46 and providing a corresponding power measurement signal to the control unit 46. The first power measurement circuit 64 is connected to the signal distributor 76 and measures the vertical received power of the vertical signal component of the received signal. The second power measurement circuit 80 is connected to the phase shift circuit 82 and measures the horizontal received power of the horizontal received signal component of the received signal. In this configuration, the control unit 46 is configured to evaluate and process the power determined by the power measurement circuits 64 and 80 accordingly to determine the presence of a circularly polarized received signal from the toll detection system 68 and, if necessary, its strength. Subsequently, the attenuation circuit 44 can be adjusted in terms of attenuation based on the circularly polarized received signal.

[0081] While the embodiments relate to vertically and horizontally polarized electromagnetic waves, the invention is not limited thereto. Other linearly polarized electromagnetic waves can, of course, be used instead of vertically polarized electromagnetic waves. Correspondingly, other electromagnetic waves orthogonally polarized relative to linearly polarized electromagnetic waves can, of course, be used instead of horizontally polarized electromagnetic waves. In particular, the electromagnetic wave only needs to be partially orthogonally polarized, for example, in circularly polarized electromagnetic waves. Antenna elements can be constructed accordingly. Therefore, the antenna element can have at least one first antenna element constructed and / or oriented in a manner matching the linearly polarized electromagnetic wave. Furthermore, the antenna element can have at least one second antenna element constructed and / or oriented in a manner orthogonally matching the first antenna element.

[0082] The embodiments are merely illustrative of the invention and should not be construed as limiting the invention.

Claims

1. A method for a communication device (32, 34) for operating a motor vehicle (14), wherein the communication device (32, 34) communicates with at least one other motor vehicle (16) or at least one static counterpart station (12), wherein, Wireless communication connections (20, 22, 24) based on linearly polarized electromagnetic waves are used, wherein, in order to use the communication connections (20, 22, 24), communication devices (32, 34) transmit signals at a preset transmission power, wherein the transmission power is reduced based on the reception of a received signal by the communication devices (32, 34) using electromagnetic waves that are at least partially orthogonal to the linearly polarized electromagnetic waves, wherein the linearly polarized electromagnetic waves are vertically polarized electromagnetic waves, and the electromagnetic waves orthogonally polarized to the vertically polarized electromagnetic waves are at least partially horizontally polarized electromagnetic waves. The method determines whether the received signal uses circularly polarized electromagnetic waves, acquires and evaluates the horizontal received power of the horizontal received signal component and the vertical received power of the vertical received signal component to determine the received power, generates the received power from the horizontal received power and the vertical received power by means of a power combiner, adjusts the phase of the horizontal received signal component to compensate for the operating time difference caused by the acquisition and / or evaluation of the received signal components by the communication devices (32, 34), and reduces the transmit power when the received power of the received signal is greater than a preset comparison value.

2. The method according to claim 1, characterized in that, The transmit power is reduced based on the received power of the received signal.

3. A communication device (32, 34) for installation in a motor vehicle (14), wherein, The communication devices (32, 34) are designed to communicate with at least one other motor vehicle (16) or at least one static counterpart station (12), wherein a wireless communication connection (20, 22, 24) based on linearly polarized electromagnetic waves is used, wherein the communication devices (32, 34) are configured to transmit a signal at a preset transmission power in order to use the communication connection (20, 22, 24), wherein the communication devices (32, 34) are designed to reduce the transmission power according to the reception of a received signal using an electromagnetic wave that is at least partially orthogonal to the linearly polarized electromagnetic wave, wherein the linearly polarized electromagnetic wave is a vertically polarized electromagnetic wave, and the electromagnetic wave orthogonally polarized to the vertically polarized electromagnetic wave is a vertically polarized electromagnetic wave. It is an electromagnetic wave that is at least partially horizontally polarized, wherein the communication devices (32, 34) are designed to determine whether the received signal uses a circularly polarized electromagnetic wave, wherein the horizontal received power of the horizontal received signal component and the vertical received power of the vertical received signal component are acquired and evaluated to determine the received power, wherein the received power is generated by means of a power combiner from the horizontal received power and the vertical received power, wherein the communication devices (32, 34) are configured to adjust the phase of the horizontal received signal component to compensate for the operating time difference that occurs due to the acquisition and / or evaluation of the received signal component by the communication devices (32, 34), and reduce the transmission power when the received power of the received signal is greater than a preset comparison value.

4. The communication device according to claim 3, characterized in that, The communication devices (32, 34) are designed to be connected in communication technology to the controller (28) of the wireless toll detection system that can be placed in the vehicle (14).

5. A motor vehicle (14) having communication devices (32, 34) for communicating with at least one other motor vehicle (16) or at least one static counterpart station (12), characterized in that, The communication device (32, 34) is the communication device according to claim 3 or 4.

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