The invention relates to a method for the wireless transmission of radio signals between vehicles, in particular commercial vehicles, a platoon, as well as a communication device for carrying out the method.
In a platoon or a convoy of several vehicles driving one behind the other, preferably commercial vehicles, a vehicle distance is conventionally set between the vehicles, which leads to low fuel consumption and better road utilization, in particular by exploiting the slipstream of a preceding vehicle, the so-called front vehicle , At the same time, a safe minimum distance is maintained so as not to cause a rear-end collision during emergency braking.
In this case, the vehicle spacing is set by a follower vehicle following the preceding vehicle itself by intervention in the brake system or the drive system, resorting to driving situation data of the preceding vehicle which characterize the current driving situation of the preceding vehicle, via wireless data communication from the other vehicles the platoon, for example, by a platoon coordinating vehicle transferred. The wireless data transmission takes place via a radio channel which permits a secure and reliable transmission of data relevant for the control of the following vehicle, by means of which the following vehicle can set the vehicle distance.
According to WO 2009/043644 A1
For example, it is provided to communicate in an automatic driving state during a convoy, ie in a platoon, between the individual vehicles directly or indirectly via a central station wirelessly to be able to set a wirelessly transmitted distance via a distance control device (ACC). A comparable system is also in US 2016 / 0054735A1
In case of failure or malfunction of the radio channel is conventionally intended to go into a safe distance mode to avoid the risk of rear-end collision, since no current data can be exchanged between the vehicles. Accordingly, the platoon is dissolved in this case, for safety reasons and each vehicle continues on its own with a safe distance to the vehicle ahead. However, this can not be made possible by a platoon or a convoy fuel saving and an optimization of the road load, since outside the platoon greater safety distances are observed.
In DE 10 2010 038 640 A1
is described to transmit data depending on their character via a first radio channel and / or via a second radio channel from one vehicle to another vehicle, wherein the first radio channel has a higher latency than the second radio channel. The selection as to whether the data is transmitted via the first or the second radio channel takes place here as a function of the information which is to be transmitted. If, accordingly, a security-relevant or aperiodically occurring information is to be transmitted, it is avoided to use the second radio channel with the lower latency and, in the case of non-safety-critical information, to the first radio channel. Accordingly, the character or security relevance and the dynamics of the transmitted information are decisive for the selected radio channel.
In DE 10 2014 211 013 A1
is provided to collect information about a traffic event centrally to create a communication message, which is then sent over two communication interfaces with different communication technology wirelessly, so that the generated communication message can be received by other vehicles. As a traffic event here comes, for example, a vehicle emergency braking, a vehicle wrong driving, a vehicle accident, a vehicle defect, a vehicle collision, an occurrence of a traffic obstruction, an occurrence of a traffic jam, or occurrence of a traffic hazard in question.
US 8,913,544 B2
describes a wireless transmission of data between vehicles and a central server, wherein it is provided via a communication device ad hoc exchange data on the current driving situation via a first radio channel between two vehicles that are in range, both data is received as data sent. Received data continues to be transmitted to a central server via a base station, whereby a host vehicle is selected in a particular region based on transmission characteristics. This transmits the information received via the first radio channel from the other vehicles to the base station and the central server.
According to DE 10 2007 030 430 A1
is provided to receive data via a mobile communication and / or a short-range wireless communication and evaluate and wirelessly to in-vehicle mobile devices, such as navigation devices to transmit.
It is an object of the invention to provide a method for wireless transmission of radio signals between vehicles of a platoon, with in a simple way, a secure and reliable wireless data transmission in a platoon can be guaranteed. It is another object of the invention to provide a communication device for carrying out the method.
This object is achieved by a method for the wireless transmission of radio signals between vehicles of a platoon according to claim 1 and a communication device according to claim 13. Preferred developments are specified in the subclaims.
According to the invention, it is accordingly provided to transmit a first radio signal via a first radio channel and a second radio signal via a second radio channel, wherein the radio signals each have redundant and / or identical driving situation data of a preceding vehicle and the transmitted redundant and / or identical driving situation data of Front vehicle for controlling and controlling a driving dynamics of a follower vehicle can be used to adjust a vehicle distance between the front vehicle and the following vehicle in the platoon, for example via a distance control device (ACC) in the following vehicle.
The front vehicle is here understood to be any preceding vehicle in the platoon, which is followed directly by a vehicle - the following vehicle. The driving situation data of the preceding vehicle can be transmitted via the respective radio channel directly from the front vehicle to the following vehicle or from any other vehicle of the platoon, preferably from a vehicle that coordinates the platoon and also processes the driving situation data of the respective front vehicle.
The transmitted driving situation data of the preceding vehicle, which describe a current driving situation of the front vehicle in the platoon or from which the current driving situation of the front vehicle can be derived in the platoon, are preferably at least one current front vehicle speed and / or one current front vehicle acceleration and / or a current front-end position. All of the forward vehicle driving situation data enables the follower vehicle to determine how the front vehicle is currently moving and how small the vehicle distance can be from the distance control of the following vehicle without causing a rear-end collision, while maintaining efficient vehicle spacing by engaging a drive system or to set a brake system in the following vehicle.
The first radio channel and the second radio channel in this case have different transmission characteristics, wherein a first frequency range is selected for the first radio channel and a second frequency range deviating from the first frequency range for the second radio channel. As a result, a diverse redundancy can advantageously be formed. That There are redundantly provided driving situation data for controlling and regulating the driving dynamics of the follower vehicle in order to be able to fall back on the respective other radio channel in case of failure or failure of one of the radio channels. For this purpose, different frequency ranges are selected so that simultaneous failures of both radio channels can be avoided by one and the same source of interference or error source.
Due to the fact that the driving situation data are transmitted redundantly via both radio channels, it is advantageously possible to compensate for a failure of a radio channel by recourse to the respective other radio channel. For this purpose, the redundant driving situation data transmitted via both radio channels can be identical or at least comparable. As a result, the following vehicle can in any case resort to vehicle-dynamic information from the vehicle in front, with which the following vehicle can set a safe vehicle distance, without having to dissolve the platoon for safety reasons. Thus, advantageously, even in the event of a failure or disruption of one of the radio channels, the benefits of a platoon, i. In particular, the saving of fuel and optimizing the road utilization are made possible.
Preferably, a first latency is determined for the first radio channel and a second latency for the second radio channel, which is higher than the first latency, so that safety-critical real-time requirements can be met by the first radio channel. The latency of the information transmission on the second radio channel does not necessarily have to fulfill these real-time requirements and can therefore be selected higher, wherein the second latency should not exceed the value of typically 200-500 ms. As a result, advantageously different requirements for the data transmission can be achieved. Accordingly, data can be transmitted very quickly over the first radio channel, so that the following vehicle can respond in a timely manner, while a large amount of data can be transmitted via the second radio channel, so that the control and regulation of the following vehicle can be based on a large amount of information.
In this case, a low first latency can preferably be achieved in that a first transmitted over the first radio channel Radio signal has a weak encryption. This means that less data is needed for encryption and decryption, and therefore a transmission can take place more quickly.
Furthermore, it can preferably be provided to transmit the first radio signal over the first radio channel only unidirectionally, the first radio signal preferably being transmitted by a platoon-coordinating vehicle and / or the front vehicle via the first radio channel to the respective following vehicle in the platoon. Ie. the transmitted amount of data of the first radio channel is reduced by avoiding unnecessary data transmissions from the following vehicle to the front vehicle or to any other vehicle in the platoon, for example by simply switching a radio signal providing or receiving communication device on the follower vehicle to a receive mode.
In order to achieve optimum transmission characteristics of the first radio channel, the first frequency range of the first radio channel is preferably set to less than 2GHz, for example, 433MHz or 868MHz or 1.9MHz for forming a DECT connection in the ISM band, and less for a first bandwidth than 20 MHz or less than 11 Mbit / s. By limiting the bandwidth, the first latency is advantageously kept low. Furthermore, the first frequency range of less than 2 GHz advantageously forms a robust wireless radio link over the first radio channel since radio signals of frequencies less than 2 GHz will cause objects, i. especially vehicles, loads and vegetation, penetrate and from massive objects, e.g. the roadway or edge structures, can also be reflected.
Thus, the first radio channel is advantageously tuned to a direct, reliable and fast data transmission between the vehicles of the platoon, in particular via the first radio channel due to the selected first frequency range, a short-range wireless communication between the vehicles, i. a so-called vehicle-to-vehicle communication can be formed.
Preferably, the second frequency range of the second radio channel is set to more than 2 GHz and a second bandwidth to more than 20 MHz or more than 11 Mbit / s. As a result, a transfer of a large number of data is advantageously made possible via the second radio channel. The second frequency range is, for example, 2.1 GHz for forming a UMTS connection or at 2.4 GHz or 5.9 GHz for forming a WLAN connection or at 2.6 GHz for forming an LTE connection or between 2 GHz and 66GHz to form a WiMax connection.
All these connections of the second radio channel advantageously allow bidirectional transmission of data both between the vehicles, i. A vehicle-to-vehicle communication, as well as a bidirectional transmission between the vehicles via a cloud-based system or a router, i. A vehicle-to-infrastructure communication, so that a transmission over longer ranges is possible. Furthermore, a multiplicity of data can thus be transmitted, so that additional information about the current driving situation can be transmitted as a supplement to the first radio channel via the second radio channel in order to improve the coordination of the platoon. This additional information on the current driving situation can also be present, for example, in the form of image data of a surroundings recognition in the preceding vehicle or in the following vehicle, with which an improved detection of the environment and thus also a reliable determination and adjustment of the vehicle distance is made possible. Thus, each radio channel has its advantages, which can be used depending on each other for a coordination of the vehicle distance.
In the event of failure of one of the radio channels, no dependent use of both radio channels is possible, however, due to the redundantly transmitted driving situation data can still be accessed on the vehicle dynamics information from the front vehicle, then on the first or the second radio channel, so that the performance of the vehicle control or regulation of the follower vehicle is reduced. However, the failure or malfunction is only an exceptional case, so that even in this exceptional case, the advantage can be achieved that the platoon does not have to be resolved, but with reduced performance nevertheless a fuel economy and an optimization of the road utilization is possible.
If, therefore, the first radio channel fails, a lower transmission time is to be accepted due to an increased transmission time, and if the second radio channel fails, a smaller number of data (bandwidth) characterizing the current driving situation must be used. The distance control in the following vehicle can take this exceptional case into account and set a slightly higher vehicle distance than in normal operation with two functioning radio channels.
Thus, a redundancy can be built with the normal operation, a high performance and in case of failure, at least a reduced Performance of the vehicle control of the follower vehicle can be ensured.
For providing the radio channels and for transmitting the radio signals, a communication device is provided in each of the vehicles of the platoon, each having two transmitters and two antennas, via which the first radio signal and the second radio signal can be transmitted and received via the respective radio channel. From the preceding vehicle and / or preferably a vehicle controlling the platoon, the driving situation data of the preceding vehicle can thus be transmitted to the following vehicle, and image data can additionally be received from the following vehicle via the second channel. The following vehicle receives the driving situation data of the respective channel via the respective antenna and, depending on the distance control device, can control a drive or braking system in the following vehicle in order to adjust the vehicle distance. Prior to transmission, the driving situation data can additionally be strongly or weakly encrypted depending on the radio channel used.
The invention will be explained below with reference to the accompanying drawings. Show it:
- 1 a schematic structure of a platoon;
- 2 a flow chart of the method according to the invention.
According to 1 is a convoy or a platoon 100 from two vehicles, a front vehicle 10 and a follower vehicle 20 represented. Basically, other vehicles can also be in the platoon 100 be provided, then as a follower vehicle in the platoon 100 is referred to, which follows a preceding vehicle - the front vehicle - directly, ie between the following vehicle and the front vehicle is a vehicle distance A set. The communication between the front vehicle 10 and the following vehicle 20 or generally between the vehicles of the platoon 100 takes place over a wireless data communication 30 instead, allowing a monitoring or coordination of the platoon 100 depending on exchanged information. Wireless communication takes place via two independent radio channels K1 . K2 instead, which are provided by a communication device 40.
These are at the communication device 40 two transmitters 41a . 41b arranged, each radio signals S1 . S2 in a certain frequency range or frequency band dF1 . dF2 output. For wireless reception of the radio signals S1 . S2 are at the communication device 40 furthermore two antennas 42a . 42b arranged. Each of the vehicles 10 . 20 in the platoon 100 has such a communication device 40 on to a wireless exchange of data or information between the vehicles 10 . 20 to enable.
According to this embodiment, from a first transmitter 41a the communication device 40 first radio signals S1 spent in a first frequency range dF1 lie. The first frequency range dF1 lies here in an ISM band (Industrial, Scientific and Medical), ie at z. B. 433MHz or 868 MHz, or equal to one DECT Standard (Digital Enhanced Cordless Telecommunications), ie about 1.9 MHz to form a DECT connection DECT , Accordingly, for the first radio channel K1 a first frequency range dF1 preferably below 2 GHz. This allows a robust wireless wireless connection over the first radio channel K1 be formed because radio signals S1 With frequencies of less than 2 GHz objects, ie in particular vehicles, loads and vegetation, penetrate and solid objects, such as the road or edge developments, can also be reflected. Thus, a secure and reliable transmission of the first radio signal S1 to the other vehicle 10 . 20 be guaranteed.
About the first station 41a and the first antenna 42a thus becomes a wireless transmission of the first radio signals S1 via a first radio channel K1 allows, over the first radio channel K1 due to the selected first frequency range dF1 in particular a short-range wireless communication between the vehicles 10 . 20 can take place, ie via the first radio channel K1 is preferably a so-called. Vehicle-to-vehicle communication V2V educated.
A first bandwidth B1 of the first radio channel K1 For example, it is set to less than 20 MHz or less than 11 Mbit / s to achieve the lowest possible first latency ta1 for the first radio channel K1 to enable. This is done via the first radio signal S1 just transmit such a small amount of data per time that a first latency ta1 of less than 50ms, for example. The reduction in the amount of data can be achieved, for example, that the over the first radio signal S1 transmitted data are weakly encrypted. Furthermore, there is a transmission of data via the first radio channel K1 only unidirectionally, with the first radio channel K1 preferably only data from the front vehicle 10 or in several vehicles of which the Platoon 100 coordinating vehicle to the follower vehicle 20 be transmitted.
In which direction the first radio signals S1 are transmitted via the first radio channel K1, thus depends on whether the respective vehicle a fore vehicle 10 or the platoon 100 coordinating vehicle or a follower vehicle 20 is. It is assumed that the platoon 100 from the front vehicle 10 is coordinated, becomes the front vehicle 10 only first radio signals S1 over the first radio channel K1 send and the follower vehicle 20 only these first radio signals S1 receive as soon as an assignment of the position has taken place and the vehicles 10 . 20 in the appropriate order in the platoon 100 are located. This is the communication device 40 in the following vehicle 20 for example, switched such that it is no longer switched to a transmission mode and the first transmitter 41 a of the follower vehicle 20 thus no longer outputs data to the first radio channel K1 not to burden. The first recipient 42a In the front vehicle 10, accordingly, no more data is received in order to continuously receive the first radio signals S1 to spend. This will cause the amount of data transferred and thus the first latency ta1 kept low, thereby enabling fast data transmission.
The front vehicle 10 sends to coordinate the platoon 100 over the first radio channel K1 Driving situation data of the fore vehicle 10 to the follower vehicle 20 , This driving situation data, the current driving situation of the front vehicle 10 in the platoon 100 characterize or can be derived from it. As a driving situation data, for example, a front-end vehicle speed VVF and / or a front-end acceleration aVF and / or a front vehicle position PVF used, with the front-vehicle position PVF a current spatial geographic position of the front vehicle 10 indicates. The following vehicle 20 can then, on the basis of this received data, immediately have its own follower vehicle speed VFF and / or a separate follower vehicle acceleration AFF set, for example via a distance control system (ACC) 80 to ensure a safe vehicle distance A between your own follower vehicle 20 and the front vehicle 10 in the platoon 100 regulate fuel consumption and road utilization. The vehicle distance A can in this case from the distance control system 80 For example, be set based on pre-parameterized criteria, after the current driving situation of the front vehicle 10 was rated.
Thus, with the over the first radio channel K1 transmitted driving situation data of the front vehicle 10 an immediate control and regulation of the follower vehicle 20 done to the position of the vehicles 10 . 20 in the platoon 100 to coordinate, taking the driving situation data of the front vehicle 10 due to the low first latency ta1 fast on the following vehicle 20 be transmitted. This allows a timely response of the follower vehicle 20 on the front of the vehicle 10 issued driving situation data are guaranteed, so that a high performance of the vehicle control or vehicle control of the follower vehicle 20 present, with the optimized vehicle spacing A is set.
At the first latency ta1 are kept low over the first radio channel K1 transmitted driving situation data of the front vehicle 10 reduced to a minimum or to the essentials. The first radio channel K1 So is on a direct, reliable and fast data transfer between the two vehicles 10 . 20 Voted.
Furthermore, simultaneously and independently to the first radio channel K1 from a second transmitter 41b the communication device 40 second radio signals S2 over a second radio channel K2 spent in a second frequency range dF2 lie and from a second antenna 42b can be received. The second frequency range dF2 differs from the first frequency range dF1 to train a diverse redundancy. That is, in case of failure or malfunction of the first radio channel K1 can on the second radio channel K2 which has other transmission properties, are dodged or vice versa.
The second frequency range dF2 This can for example be at higher frequencies and the WIRELESS INTERNET ACCESS Standard IEEE 802.11 b / g, ie 2.4 GHz, or the WIRELESS INTERNET ACCESS Standard IEEE 802.11p, ie in the ISM band between 5.85 and 5.925 GHz, correspond, if with the second transmitter 41b and the second antenna 42b a WIRELESS INTERNET ACCESS -Connection WIRELESS INTERNET ACCESS for providing a Dedicated Short Range Communication (DSRC) over the second radio channel K2 should be built. Alternatively, a mobile connection via UMTS (Universal Mobile Telecommunications System), ie 2.1 GHz, LTE (Long Term Evolution Advanced), ie 2.6 GHz, or WiMax (IEEE 802.16), ie between 2 GHz and 66 GHz, enabling frequencies above 2GHz to be achieved.
About the second transmitter 41b and the second antenna 42b thus becomes a wireless transmission of second radio signals S2 over a second radio channel K2 allows, due to the selected second frequency range dF2 of more than 2 GHz both a short-range and a long-range wireless communication between the vehicles 10 . 20 can be enabled. This means over the second radio channel K2 can be both a vehicle-to-vehicle communication V2V as well as a vehicle-to-infrastructure communication V2I about which the two vehicles 10 . 20 for example, via a Cloud-based system 50 or a router 60 can communicate with each other, are trained. In 1 is merely exemplary of the second channel K2 a vehicle-to-infrastructure communication V2I shown.
In order in this second frequency range dF2 Can reduce problems with shadowing, can be resorted to a MIMO antenna technology (Multiple Input Multiple Output) by the second transmitter 41b and the second antenna 42b divided into several transmitting or antenna units.
The second frequency range dF2 is chosen such that a high second bandwidth B2 with over 20MHz or more than 11MBit / s can be achieved. The second radio channel K2 is thus designed to be over the second radio signal S2 as many driving situation data as possible of the vehicle in front 10 to transfer, for example, from an environment detection 70 recorded image data B of the surroundings of the front vehicle 10 or the follower vehicle 20. Over the second radio channel K2 Thus, in particular additional information is transmitted, which is also an evaluation of the driving situation of the vehicle in front 10 allow and therefore to improve the adjustment of the vehicle distance A and thus to an improved coordination of the platoon 100 by appropriate control and regulation of the follower vehicle 20 can be used.
For the second radio channel K2 is in contrast to the first radio channel K1 a bidirectional connection, for example after Collision Detected Multiple Access (CDMA), provided, which also has a strong encryption, eg WPA2 (Wi-Fi Protected Access 2), for a high security of this second radio channel K2 to ensure. A second latency following the high amount of data transferred tL2 of the second radio channel K2 is higher than the first latency ta1 ie higher than, say, 50ms, with the second latency tL2 should not exceed the value of typically 200-500 ms. Because a quick coordination of the platoon 100 in normal operation and thus a high performance of the vehicle control of the follower vehicle 20 but through the parallel over the first radio channel K1 transmitted data can be the second latency tL2 higher.
Nevertheless, even with a (partial) failure or a fault of the first radio channel K1 , a coordination of the platoon 100 to be enabled via the second radio signal S2 also the driving situation data of the front vehicle 10 for a coordination of the platoon 100 are needed and in normal operation over the first radio channel K1 be transmitted. These are, for example, the front vehicle speed VVF and / or the front vehicle acceleration aVF and / or the front vehicle position PVF. Alternatively, redundant data can also be transmitted, ie data having the same information content. Due to the higher second latency tL2 there is a control and regulation of the follower vehicle 20 by which the vehicle distance A is set, but then with at least reduced performance compared to a use of the first radio channel K1 transmitted driving situation data.
The second radio channel K2 Thus, on the one hand, it serves the bidirectional provision of additional information, the even more precise coordination of the platoon 100 or an optimized setting of the vehicle distance A allow, as well as the formation of a diverse redundancy, in which even in case of (partial) failure or disruption of the first radio channel K1 both vehicles 10 . 20 - at least with reduced performance - still in the platoon 100 can continue without the Platoon 100 to dissolve.
Both radio channels K1 . K2 So they can be used independently or independently to the platoon 100 to coordinate. An independent coordination takes place in particular in the case of a (partial) failure or a fault in one of the radio channels K1 . K2 to the platoon 100 at least maintain, with the vehicle spacing A then no longer with optimal performance is set:
If the first radio channel falls K1 is deviated from the optimum due to an increased transmission time, there on the second radio channel K2 is used. On the other hand falls the second radio channel K2 is deviated from the optimum due to a lower number of driving situation data (bandwidth), which characterize the current driving situation, since only to the transmitted information of the first radio channel K1 can be used.
Can completely on both radio channels K1 . K2 can be accessed, both radio channels K1 . K2 be used independently of each other, and thus the benefits of both are used to provide high safety and reliability optimized vehicle spacing A depending on a variety of additional information.
By using both radio channels K1 . K2 Furthermore, the security of data transmission can be increased by using a symmetric key V , the first radio channel K1 encrypted, over the second radio channel K2 transferred and changed regularly. Thus, hacking or interfering with both radio channels K1, K2 is required for an external access or intervention.
The inventive method can according to 2 for example, in an initial step St0 be initialized, for example, with the start of the vehicle 10 . 20 , In a first step St1 is by the communication device 40 in each vehicle 10 . 20 a first and a second channel K1 . K2 with the respective frequency ranges dF1 . dF2 and bandwidths B1, B2 provided to enable wireless data exchange as described.
In a second step St2 will be over the two channels K1 . K2 redundant driving situation data VVF . aVF . PVF of the front vehicle 10 transferred to form a diverse redundancy as described. In a third step St3, the driving dynamics VFF . AFF of the following vehicle 20 so to the current driving situation VVF . aVF . PVF of the front vehicle 10 adjusted that a certain vehicle distance A between the vehicles 10 . 20 , the platoon 100 established.
LIST OF REFERENCE NUMBERS
- front vehicle
- the following vehicle
- wireless data communication
- 41a, 41b
- 42a, 42b
- Cloud-based system
- environment recognition
- Distance control system
- Follow vehicle acceleration
- The preceding vehicle acceleration
- first bandwidth
- second bandwidth
- DECT connection
- first frequency range
- second frequency range
- first radio channel
- second radio channel
- LTE connection
- The preceding vehicle position
- first radio signal
- second radio signal
- first latency
- second latency
- UMTS connection
- Key to encrypt the first radio channel
- Vehicle-to-vehicle communication
- Vehicle-to-infrastructure communication
- Follow vehicle speed
- Front vehicle speed
- WiMax connection
- WIRELESS INTERNET ACCESS
- Wi-Fi connection
QUOTES INCLUDE IN THE DESCRIPTION
This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
Cited patent literature
- WO 2009/043644 A1 
- US 2016/0054735 A1 
- DE 102010038640 A1 
- DE 102014211013 A1 
- US 8913544 B2 
- DE 102007030430 A1