Patent ID: 12238576

The figures are only schematic and not true to scale. The same reference numerals designate the same or functionally equivalent features in the figures.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG.1shows an example of four vehicles101,102,103,104, each of which is equipped with a sensor system106for detecting surroundings, an evaluation unit108for evaluating sensor data110generated by sensor system106, and an actuator system112. Evaluation unit108is furthermore configured to send and/or receive a message114via a wireless V2X communications network, in which the four vehicles101,102,103,104are networked with each other, based on sensor data110. A received message114may be evaluated by evaluation unit108, for example to activate actuator system112. It is thus possible, for example, to coordinate individual driving maneuvers of vehicles101,102,103,104in an automated manner, which may also be referred to as cooperative driving.

InFIG.1, the three vehicles101,103,104drive on an expressway115, while vehicle102is in the process of entering expressway115.

For example, sensor system106is implemented as a camera. However, sensor system106may also include multiple sensor units of different types. For example, sensor system106may include, for example, at least one radar, LIDAR or ultrasonic sensor or laser scanner in addition or as an alternative to the camera.

Actuator system112may include, for example, a steering or brake actuator or an actuator for controlling the engine. Evaluation unit108may be designed to generate a control signal116for activating actuator system112, based on sensor data110and/or message114, for the purpose of controlling, i.e., steering, braking, accelerating the relevant vehicle in an automated manner, or to navigate it according to a predefined route in a digital map, for example, taking into account anticipated trajectories of the other vehicles in each case.

Evaluation unit108is configured, in particular, to extract objects in the surroundings from sensor data110, for example, adjacent vehicles or their possible trajectories. Evaluation unit108of vehicle103thus recognizes, for example, the three vehicles101,102,104. Upon recognition, evaluation unit108assigns a priority value to each of the recognized objects, which quantifies a relevance of the recognized object for vehicle103. In this example, for example, the two vehicles101,104receive a lower priority value than entering vehicle102, whose trajectory is expected to intersect with a trajectory of vehicle103.

In addition, evaluation unit108ascertains an instantaneous channel capacity utilization of a radio channel, via which vehicles101,102,103,104communicate with each other. Based on the instantaneous channel capacity utilization and the particular priority values, evaluation unit108now selects from among the recognized objects the ones which are particularly relevant, in this case, for example, recognized vehicle102, and generates and sends a message114including a piece of relevant information, for example, about the position, velocity, trajectory of recognized vehicle102. Less relevant objects are excluded from message114, to avoid unnecessarily loading the radio channel. Message114may be received by other vehicles, for example by vehicles101,104.

The individual steps of a priority-based message generation of this type, taking into account a channel capacity utilization, are described in detail below, based on the example of evaluation unit108of vehicle103. However, the description may also apply in the same or similar way to evaluation units108of other vehicles101,102,104.

FIG.2shows a filter list L1generated by evaluation unit108, based on sensor data110, including different message segments S1, S2, S3, S4, S5, each of which describes a recognized object in the surroundings of vehicle103, including, for example, vehicles101,102,104. Each of message segments S1, S2, S3, S4, S5is marked with a priority value pi, which indicates a particular priority of the object described in the message segment.

Based on a threshold value comparison, in a first step, evaluation unit108removes message segments S1, S3having low priority values p1and p3from filter list L1, which thereby becomes a shortened filter list L′1. In a second step, evaluation unit108creates a transfer list L2from message segments S2, S4, S5contained in shortened filter list L′1, which, in this case, contains message segments S2, S4having particularly high priority values p2and p4. Transfer list L2is created in such a way that it does not exceed a predefined maximum message size. In this example, the message size is not sufficient, for example, to add message segment S5to transfer list L2in addition to the two message segments S2, S4. Evaluation unit108determines the maximum message size, for example, from the instantaneous channel capacity utilization, as described in greater detail below, based onFIG.3.

Finally, evaluation unit108generates message114from transfer list L2. Message114contains not only message segments S2, S4to be transferred from transfer list L2but also a header H including obligatory data about vehicle103and its sensor system106, among others.

FIG.3shows a flowchart of a method300for transferring message114. Method300may be carried out, for example, by evaluation unit108according toFIG.2.

In a first step301, a message sent by another road user101,102,104is received in evaluation unit108, the message containing message segments S1through S5to be filtered, which have priority values p1through p5.

In a further step303, filter list L1is created, which includes message segments S1through S5having associated priority values p1through p5.

Alternatively sensor data110are optionally received in evaluation unit108in first step301. In a further optional step302, objects101,102,104are recognized in the surroundings of vehicle103by a corresponding processing and evaluation of sensor data110. Different priority values p1are assigned to objects101,102,104, depending on their relevance. In step303, filter list L1is created, which includes message segments S1through S5to be filtered, which have associated priority values p1through p5and describe objects101,102,104.

An instantaneously available data transfer rate Raof a radio channel assigned to the communications network is determined in a further step304.

In a further step305, a maximum message size Mmaxof a message to be transferred and a priority threshold value pthare calculated from instantaneously available data transfer rate Ra.

In a further step306, filter list L1is filtered with maximum message size Mmaxand priority threshold value pthas filter criteria. Message segments S1, S3including priority values p1and p3below priority threshold value pthare removed from filter list L1. Message segments are selected from message segments S2, S4, S5including priority values p2, p4and p5above priority threshold value pthfor priority list L2until maximum message size Mmaxis reached. This is the case here after message segments S2, S4have been added to transfer list L2.

Finally, in a step307, message114is generated from transfer list L2and transferred via the radio channel in the communications network.

Method300described above may be viewed as an extension of an ETSI DCC protocol mentioned further above. Filter list L1may be provided, for example, by an application layer and received by an underlying layer, for example a DCC protocol. Upon the receipt of filter list L1, for example the following six principle steps may be carried out by the DCC protocol. However, it is also possible that only the first two of the six steps are carried out by the DCC protocol, while the remaining steps are carried out by the application layer. In this way, it is possible to avoid lists of message segments being exchanged between the application layer and the DCC protocol.

1. A data transfer rate Rainstantaneously available for a transfer is first estimated in step304. For example, an instantaneous channel busy ratio CBR may be measured for this purpose. Channel busy ratio CBR describes a time portion, in which the radio channel is used by other stations (0≤CBR≤1). Based on measured channel busy ratio CBR and an available data rate R of the radio channel, which may be advantageously estimated from a total data rate, and may be, for example, two-thirds of the total data rate, available throughput Rais calculated to:
Ra=(1−CBR)·R[Mbit/s]

2. Based on available throughput Raand a time T which has elapsed since a last message transfer, in step305maximum message size Mmaxis calculated to:
Mmax=Ra·T[bit]

3. In Step305, priority threshold value pthis furthermore calculated as a function of channel busy ratio CBR, a higher channel busy ratio CBR resulting in a higher priority threshold value pthand vice versa. Alternatively or additionally, priority threshold value pthmay be ultimately calculated, based on a statistical distribution of priority values pi, for a transfer of selected message segments Si, for example based on an arithmetic mean value or a median. Priority threshold value pthis greater, the greater are priority values p1of message segments Silast selected, and vice versa.

4. In a step308, all message segments S1, S3are now discarded from filter list L1, whose priority value p1or p3is below priority threshold value pth. Filter list L1is shortened accordingly thereby. If, at the outset, filter list L1contains only message segments Siincluding priority values p1below priority threshold value pth, entire filter list L1, for example, is discarded, and the method is aborted in a step309.

5. In a step310, transfer list L2is created as a new empty list. Message segments for transfer list L2are now selected from message segments S2, S4, S5of shortened filter list L′1.

6. For this purpose, filter list L1is processed step by step. Message segment S2including highest priority value p2is first selected in step310. A message segment size M of selected message segment S2is ascertained in a step311. Message segment size M is compared with maximum message size Mmaxin a step312.

If M<Mmax, selected message segment S2is added to transfer list L2in a step313and removed from filter list L′1in a step314. Finally, maximum message size Mmaxis reduced for a following iteration in a step315: Mmax,new=Mmax−M.

In the next iteration, steps310through315are repeated for message segments S4, S5remaining in filter list L′1. The message segment including the highest priority value is now message segment S4.

Steps310through315are generally repeated cyclically until filter list L′1is empty. With the aid of completed transfer list L2, message114is finally generated and sent in step307.

However, if it turns out in step312that a message segment Sito be added to transfer list L2is greater or equal to maximum message size Mmax, as in the case here of message segment S5, for example, it may be checked, for example, in an additional step316before generating message114whether transfer list L2contains at least one message segment Sior more than one predefined minimum number of message segments Si. If this is the case, message114is generated and sent in step307. If it is not the case, no message114is generated, and method300is aborted.

Finally, it should be noted that terms such as “having,” “including,” etc. do not exclude other elements or steps, and terms such as “a” or “one” do not exclude a plurality.