METHOD FOR TRANSFERRING A MESSAGE IN A COMMUNICATIONS NETWORK FOR COMMUNICATION BETWEEN A ROAD USER AND AT LEAST ONE FURTHER ROAD USER

Abstract

A method for transferring a message in a communications network for communication between a road user and at least one further road user. The road user and the further road user each include an evaluation unit for transferring messages via the communications network. The method includes: receiving a first message in the evaluation unit, the first message including message segments, each including a priority value; determining an instantaneous capacity utilization of the communications network; filtering message segments to be transferred out of the first message, based on the priority values and the instantaneous capacity utilization of the communications network; and generating a second message including the message segments to be transferred, and sending the second message via the communications network.

Claims

1-11. (canceled)

12. A method for transferring a message in a communications network for communication between a road user and at least one further road user, the road user and the further road user each including an evaluation unit configured to transfer messages via the communications network, the method comprising the following steps: receiving a first message in the evaluation unit, the first message including message segments which each include a priority value; determining an instantaneous capacity utilization of the communications network; filtering message segments to be transferred out of the first message, based on the priority values and the instantaneous capacity utilization of the communications network; and generating a second message, which includes the message segments to be transferred, and sending the second message via the communications network.

13. The method as recited in claim 12, further comprising: determining a maximum message size of a message to be transferred as a function of the instantaneous capacity utilization of the communications network, and determining a priority threshold value as a function of the instantaneous capacity utilization of the communications network and/or based on priority values of message segments last transferred; filtering the message segments to be transferred out of the first message, based on the maximum message size and the priority threshold value.

14. The method as recited in claim 13, wherein a filter list is created for message segments to be filtered; the priority values are each compared with the priority threshold value; the filter list is shortened by removing message segments whose priority value is below the priority threshold value; the message segments to be transferred are selected from the shortened filter list, taking into account the maximum message size.

15. The method as recited in claim 14, further comprising: selecting a message segment including a highest priority value from the shortened filter list; ascertaining a message segment size of the selected message segment; comparing the message segment size with the maximum message size; when the message segment size is smaller than the maximum message size: adding the selected message segment to a transfer list of message segments to be transferred; removing the selected message segment from the shortened filter list; reducing the maximum message size by the message segment size; wherein the steps of selecting, ascertaining, comparing, adding, removing, and reducing are repeated cyclically until the message segment size is smaller than or equal to the maximum message size, and/or all message segments have been removed from the shortened filter list; generating the second message from the transfer list, and sending the second message via the communications network.

16. The method as recited in claim 15, further comprising: checking whether the transfer list contains at least one message segment; based on the checking, generating the second message using the transfer list, and sending the second message via the communications network.

17. The method as recited in claim 13, wherein: the priority threshold value is calculated from a channel busy ratio, the priority threshold value increasing and/or decreasing along with the channel busy ratio; and/or at least one statistical characteristic is calculated from the priority values of message segments last transferred, the priority threshold value being calculated from the statistical characteristic.

18. The method as recited in claim 13, wherein the instantaneous capacity utilization of the communications network is calculated as an instantaneously available data transfer rate (R.sub.a) of a radio channel assigned to the communications network from a channel busy ratio (CBR) and a data transfer rate (R) of the radio channel to:
R.sub.a=(1−CBR).Math.R.

19. The method as recited in claim 18, wherein the maximum message size (M.sub.max) is calculated to:
M.sub.max=R.sub.a.Math.T, T being a time since the last transfer of a message via the radio channel.

20. An evaluation unit for transferring a message in a communications network for communication between a road user and at least one further road user, the evaluation unit configured to: receive a first message, the first message including message segments which each include a priority value; determine an instantaneous capacity utilization of the communications network; filter message segments to be transferred out of the first message, based on the priority values and the instantaneous capacity utilization of the communications network; and generate a second message, which includes the message segments to be transferred, and sending the second message via the communications network.

21. A non-transitory computer-readable medium on which is stored a computer program for transferring a message in a communications network for communication between a road user and at least one further road user, the road user and the further road user each including an evaluation unit configured to transfer messages via the communications network, the computer program, when executed by a processor, causing the processor to perform the following steps: receiving a first message, the first message including message segments which each include a priority value; determining an instantaneous capacity utilization of the communications network; filtering message segments to be transferred out of the first message, based on the priority values and the instantaneous capacity utilization of the communications network; and generating a second message, which includes the message segments to be transferred, and sending the second message via the communications network.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Specific embodiments of the present invention are described below with reference to the figures, neither the figures nor the description are to be interpreted as limiting the present invention.

[0037] FIG. 1 schematically shows a traffic scenario including networked vehicles, each being equipped with an evaluation unit according to one exemplary embodiment of the present invention.

[0038] FIG. 2 schematically shows how message segments are filtered by the evaluation unit according to FIG. 1.

[0039] FIG. 3 shows a flowchart of a method according to one exemplary embodiment of the present invention.

[0040] 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

[0041] FIG. 1 shows an example of four vehicles 101, 102, 103, 104, each of which is equipped with a sensor system 106 for detecting surroundings, an evaluation unit 108 for evaluating sensor data 110 generated by sensor system 106, and an actuator system 112. Evaluation unit 108 is furthermore configured to send and/or receive a message 114 via a wireless V2X communications network, in which the four vehicles 101, 102, 103, 104 are networked with each other, based on sensor data 110. A received message 114 may be evaluated by evaluation unit 108, for example to activate actuator system 112. It is thus possible, for example, to coordinate individual driving maneuvers of vehicles 101, 102, 103, 104 in an automated manner, which may also be referred to as cooperative driving.

[0042] In FIG. 1, the three vehicles 101, 103, 104 drive on an expressway 115, while vehicle 102 is in the process of entering expressway 115.

[0043] For example, sensor system 106 is implemented as a camera. However, sensor system 106 may also include multiple sensor units of different types. For example, sensor system 106 may include, for example, at least one radar, LIDAR or ultrasonic sensor or laser scanner in addition or as an alternative to the camera.

[0044] Actuator system 112 may include, for example, a steering or brake actuator or an actuator for controlling the engine. Evaluation unit 108 may be designed to generate a control signal 116 for activating actuator system 112, based on sensor data 110 and/or message 114, 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.

[0045] Evaluation unit 108 is configured, in particular, to extract objects in the surroundings from sensor data 110, for example, adjacent vehicles or their possible trajectories. Evaluation unit 108 of vehicle 103 thus recognizes, for example, the three vehicles 101, 102, 104. Upon recognition, evaluation unit 108 assigns a priority value to each of the recognized objects, which quantifies a relevance of the recognized object for vehicle 103. In this example, for example, the two vehicles 101, 104 receive a lower priority value than entering vehicle 102, whose trajectory is expected to intersect with a trajectory of vehicle 103.

[0046] In addition, evaluation unit 108 ascertains an instantaneous channel capacity utilization of a radio channel, via which vehicles 101, 102, 103, 104 communicate with each other. Based on the instantaneous channel capacity utilization and the particular priority values, evaluation unit 108 now selects from among the recognized objects the ones which are particularly relevant, in this case, for example, recognized vehicle 102, and generates and sends a message 114 including a piece of relevant information, for example, about the position, velocity, trajectory of recognized vehicle 102. Less relevant objects are excluded from message 114, to avoid unnecessarily loading the radio channel. Message 114 may be received by other vehicles, for example by vehicles 101, 104.

[0047] 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 unit 108 of vehicle 103. However, the description may also apply in the same or similar way to evaluation units 108 of other vehicles 101, 102, 104.

[0048] FIG. 2 shows a filter list L.sub.1 generated by evaluation unit 108, based on sensor data 110, including different message segments S.sub.1, S.sub.2, S.sub.3, S.sub.4, S.sub.5, each of which describes a recognized object in the surroundings of vehicle 103, including, for example, vehicles 101, 102, 104. Each of message segments S.sub.1, S.sub.2, S.sub.3, S.sub.4, S.sub.5 is marked with a priority value p.sub.i, which indicates a particular priority of the object described in the message segment.

[0049] Based on a threshold value comparison, in a first step, evaluation unit 108 removes message segments S.sub.1, S.sub.3 having low priority values p.sub.1 and p.sub.3 from filter list L.sub.1, which thereby becomes a shortened filter list L′.sub.1. In a second step, evaluation unit 108 creates a transfer list L.sub.2 from message segments S.sub.2, S.sub.4, S.sub.5 contained in shortened filter list L′.sub.1, which, in this case, contains message segments S.sub.2, S.sub.4 having particularly high priority values p.sub.2 and p.sub.4. Transfer list L.sub.2 is 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 S.sub.5 to transfer list L.sub.2 in addition to the two message segments S.sub.2, S.sub.4. Evaluation unit 108 determines the maximum message size, for example, from the instantaneous channel capacity utilization, as described in greater detail below, based on FIG. 3.

[0050] Finally, evaluation unit 108 generates message 114 from transfer list L.sub.2. Message 114 contains not only message segments S.sub.2, S.sub.4 to be transferred from transfer list L.sub.2 but also a header H including obligatory data about vehicle 103 and its sensor system 106, among others.

[0051] FIG. 3 shows a flowchart of a method 300 for transferring message 114. Method 300 may be carried out, for example, by evaluation unit 108 according to FIG. 2.

[0052] In a first step 301, a message sent by another road user 101, 102, 104 is received in evaluation unit 108, the message containing message segments S.sub.1 through S.sub.5 to be filtered, which have priority values p.sub.1 through p.sub.5.

[0053] In a further step 303, filter list L.sub.1 is created, which includes message segments S.sub.1 through S.sub.5 having associated priority values p.sub.1 through p.sub.5.

[0054] Alternatively sensor data 110 are optionally received in evaluation unit 108 in first step 301. In a further optional step 302, objects 101, 102, 104 are recognized in the surroundings of vehicle 103 by a corresponding processing and evaluation of sensor data 110. Different priority values p.sub.1 are assigned to objects 101, 102, 104, depending on their relevance. In step 303, filter list L.sub.1 is created, which includes message segments S.sub.1 through S.sub.5 to be filtered, which have associated priority values p.sub.1 through p.sub.5 and describe objects 101, 102, 104.

[0055] An instantaneously available data transfer rate R.sub.a of a radio channel assigned to the communications network is determined in a further step 304.

[0056] In a further step 305, a maximum message size M.sub.max of a message to be transferred and a priority threshold value p.sub.th are calculated from instantaneously available data transfer rate R.sub.a.

[0057] In a further step 306, filter list L.sub.1 is filtered with maximum message size M.sub.max and priority threshold value p.sub.th as filter criteria. Message segments S.sub.1, S.sub.3 including priority values p.sub.1 and p.sub.3 below priority threshold value p.sub.th are removed from filter list L.sub.1. Message segments are selected from message segments S.sub.2, S.sub.4, S.sub.5 including priority values p.sub.2, p.sub.4 and p.sub.5 above priority threshold value p.sub.th for priority list L.sub.2 until maximum message size M.sub.max is reached. This is the case here after message segments S.sub.2, S.sub.4 have been added to transfer list L.sub.2.

[0058] Finally, in a step 307, message 114 is generated from transfer list L.sub.2 and transferred via the radio channel in the communications network.

[0059] Method 300 described above may be viewed as an extension of an ETSI DCC protocol mentioned further above. Filter list L.sub.1 may 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 L.sub.1, 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.

[0060] 1. A data transfer rate R.sub.a instantaneously available for a transfer is first estimated in step 304. 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 R.sub.a is calculated to:

R.sub.a=(1−CBR).Math.R[Mbit/s]

[0061] 2. Based on available throughput R.sub.a and a time T which has elapsed since a last message transfer, in step 305 maximum message size M.sub.max is calculated to:

M.sub.max=R.sub.a.Math.T[bit]

[0062] 3. In Step 305, priority threshold value p.sub.th is furthermore calculated as a function of channel busy ratio CBR, a higher channel busy ratio CBR resulting in a higher priority threshold value p.sub.th and vice versa. Alternatively or additionally, priority threshold value p.sub.th may be ultimately calculated, based on a statistical distribution of priority values p.sub.i, for a transfer of selected message segments S.sub.i, for example based on an arithmetic mean value or a median. Priority threshold value p.sub.th is greater, the greater are priority values p.sub.1 of message segments S.sub.i last selected, and vice versa.

[0063] 4. In a step 308, all message segments S.sub.1, S.sub.3 are now discarded from filter list L.sub.1, whose priority value p.sub.1 or p.sub.3 is below priority threshold value p.sub.th. Filter list L.sub.1 is shortened accordingly thereby. If, at the outset, filter list L.sub.1 contains only message segments S.sub.i including priority values p.sub.1 below priority threshold value p.sub.th, entire filter list L.sub.1, for example, is discarded, and the method is aborted in a step 309.

[0064] 5. In a step 310, transfer list L.sub.2 is created as a new empty list. Message segments for transfer list L.sub.2 are now selected from message segments S.sub.2, S.sub.4, S.sub.5 of shortened filter list L′.sub.1.

[0065] 6. For this purpose, filter list L.sub.1 is processed step by step. Message segment S.sub.2 including highest priority value p.sub.2 is first selected in step 310. A message segment size M of selected message segment S.sub.2 is ascertained in a step 311. Message segment size M is compared with maximum message size M.sub.max in a step 312. If M<M.sub.max, selected message segment S.sub.2 is added to transfer list L.sub.2 in a step 313 and removed from filter list L′.sub.1 in a step 314. Finally, maximum message size M.sub.max is reduced for a following iteration in a step 315: M.sub.max,new=M.sub.max−M.

[0066] In the next iteration, steps 310 through 315 are repeated for message segments S.sub.4, S.sub.5 remaining in filter list L′.sub.1. The message segment including the highest priority value is now message segment S.sub.4.

[0067] Steps 310 through 315 are generally repeated cyclically until filter list L′.sub.1 is empty. With the aid of completed transfer list L.sub.2, message 114 is finally generated and sent in step 307.

[0068] However, if it turns out in step 312 that a message segment S.sub.i to be added to transfer list L.sub.2 is greater or equal to maximum message size M.sub.max, as in the case here of message segment S.sub.5, for example, it may be checked, for example, in an additional step 316 before generating message 114 whether transfer list L.sub.2 contains at least one message segment S.sub.i or more than one predefined minimum number of message segments S.sub.i. If this is the case, message 114 is generated and sent in step 307. If it is not the case, no message 114 is generated, and method 300 is aborted.

[0069] 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.