Patent Application
20230254726
This application claims priority to Japanese Patent Application No. 2022-018829 filed on Feb. 9, 2022, the entire contents of which are incorporated by reference herein.
The present disclosure relates to a technique for performing communication between a moving body and an external device.
Patent Literature 1 discloses a wireless communication system in which wireless communication is performed between a base station and a subscriber station. A communication device provided in the base station or the subscriber station includes a first wireless communication means, a second wireless communication means, and a radio frequency switching means. The first wireless communication means performs the wireless communication by using a first frequency band that is equal to or higher than a quasi-millimeter wave. The second wireless communication means performs the wireless communication by using a second frequency band that is lower than the first frequency band and has less radio wave attenuation due to rainfall. The radio frequency switching means normally selects the first radio communication means, and selects the second radio communication means when communication interruption is detected.
Patent Literature 2 discloses a transmission device. The transmission device includes a first transmission means for transmitting a packet via a first communication line, a second transmission means for transmitting a packet via a second communication line, a packet generation means for copying the packet, a monitoring means for monitoring communication states of the first and second communication lines, and a control means. The control means transmits the duplicated two or more packets by using at least one of the first and second communication lines according to the monitored communication states.
Patent Literature 3 discloses a route setting device that sets a route of a moving body having a plurality of operation modes. The route setting device sets the route of the moving body so as to pass through an area satisfying a requirement of communication quality that is determined according to an operation mode of the moving body.
Patent Literature 4 discloses a remote operation device for remotely operating a target device. The remote operation device acquires a quality of communication between the target device and the remote operation device, and sets authority of the remote operation device regarding the operation of the target device on the basis of the communication quality.
Regarding communication between a moving body such as a vehicle and a robot and an external device, it is considered that there is a need for reducing a communication cost as much as possible. Meanwhile, depending on an environment in which the moving body is placed, it is considered that there is also a need for highly reliable communication. It is important to appropriately balance low costs and high reliability in light of such needs.
An object of the present disclosure is to provide a technique capable of appropriately balancing high reliability and low costs regarding communication between a moving body and an external device.
A first aspect is directed to a communication method for performing communication between a moving body and an external device.
The communication method includes:
a mode selection process that selects one of a plurality of communication modes; and
a data transmission process that transmits transmission target data from the moving body to the external device based on the selected communication mode.
The plurality of communication modes include:
a line selection mode that selects one of communication lines available to the moving body and transmits the transmission target data by using the selected one communication line; and
a redundant transmission mode that transmits same packets of the transmission target data in parallel by concurrently using multiple communication lines available to the moving body.
The mode selection process includes:
determining whether or not reliable communication is necessary based on environmental information indicating an environment in which the moving body is placed;
selecting the redundant transmission mode when it is determined that the reliable communication is necessary; and
selecting the line selection mode when it is determined that the reliable communication is not necessary.
A second aspect is directed to a communication device that is installed on a moving body and communicates with an external device.
The communication device includes a communication controller configured to select one of a plurality of communication modes and to transmit transmission target data to the external device based on the selected communication mode.
The plurality of communication modes include:
a line selection mode that selects one of communication lines available to the moving body and transmits the transmission target data by using the selected one communication line; and
a redundant transmission mode that transmits same packets of the transmission target data in parallel by concurrently using multiple communication lines available to the moving body.
The communication controller is further configured to:
determine whether or not reliable communication is necessary based on environmental information indicating an environment in which the moving body is placed;
select the cost-oriented selection mode when the communication quality of the first communication line satisfies the predetermined level; and
select the quality-oriented selection mode when the communication quality of the first communication line does not satisfy the predetermined level.
According to the present disclosure, the plurality of communication modes include the line selection mode that is low-cost and the redundant transmission mode that is highly reliable and low-latency. Whether or not to give priority to the reliable communication depends on the environment in which the moving body is placed. Therefore, whether or not the reliable communication is necessary is determined based on the environmental information indicating the environment in which the moving body is placed. When it is determined that the reliable communication is necessary, the redundant transmission mode is actively selected. On the other hand, when it is determined that the reliable communication is not necessary, the line selection mode is actively selected. The redundant transmission mode is selected only when the reliable communication is necessary, and the line selection mode is selected in the other cases, which can prevent an unnecessary increase in communication cost. That is, it is possible to appropriately balance high reliability and low costs.
Embodiments of the present disclosure will be described with reference to the accompanying drawings.
The first communication device 10 is installed on a moving body 100. Examples of the moving body 100 include a vehicle, a robot, a flying object, and the like. The vehicle may be an automated driving vehicle or a vehicle driven by a driver. Examples of the robot include a logistics robot, a work robot, and the like. Examples of the flying object include an airplane, a drone, and the like.
The second communication device 20 is installed on an external device 200 outside the moving body 100. A type of the external device 200 is not limited in particular. For example, the external device 200 is a management server for managing the moving body 100. As another example, the external device 200 may be a remote support device that remotely supports an operation of the moving body 100. As yet another example, the external device 200 may be a moving body different from the moving body 100.
According to the present embodiment, the first communication device 10 installed on the moving body 100 is configured to be capable of communicating with the external device 200 via a plurality of communication lines. The first communication device 10 transmits transmission target data to the external device 200 by using a necessary number of communication lines among the plurality of communication lines. The transmission target data may be streaming data.
More specifically, the first communication device 10 supports multiple communication carriers and multiple types of communication methods (communication systems, communication protocols). Examples of the communication method include a common cellular method provided by MNO (Mobile Network Operator), an inexpensive cellular method provided by MVNO (Mobile Virtual Network Operator), a wireless LAN (Local Area Network) method, and the like. A communication cost differs among the multiple types of communication methods. In the example above, the wireless LAN method is the lowest and the common cellular method is the highest.
The plurality of communication interfaces 11 are associated with different communication carriers or different communication methods, respectively. A plurality of communication lines are established via the plurality of communication interfaces 11, respectively. In other words, the plurality of communication lines are associated with the plurality of communication interfaces 11, respectively. For example, a first communication interface 11-1 performs communication via a first communication line C1 based on a first communication method. A second communication interface 11-2 performs communication via a second communication line C2 based on a second communication method. It should be noted that the plurality of communication interfaces 11 may be realized by different physical interfaces, or may be realized by a combination of a common physical interface and different logical interfaces.
The communication controller 12 is provided to control data transmitted and received by at least one application running on the moving body 100. For example, the communication controller 12 allocates the transmission target data to one or more of the plurality of communication interfaces 11 (communication lines) to be used. Then, the communication controller 12 transmits the transmission target data to the external device 200 via the allocated communication interface 11 (i.e., the allocated communication line).
The second communication device 20 includes a network interface 21 and a communication controller 22. The network interface 21 is connected to the communication network 30 and communicates with the first communication device 10.
The communication controller 22 is provided to control data transmitted and received by at least one application running on the external device 200. For example, the communication controller 22 receives data transmitted from the first communication device 10 via the network interface 21. Then, the communication controller 22 outputs the received data to a destination application.
The communication controller 12 of the first communication device 10 according to the present embodiment has a plurality of communication modes, and selects one of the plurality of communication modes to perform the communication. Hereinafter, the plurality of communication modes of the communication controller 12 will be described.
The line selection mode MS may be further classified into the following two modes: a “cost-oriented selection mode MS1” and a “quality-oriented selection mode MS2.”
The cost-oriented selection mode MS1 selects one communication line with the lowest cost from the communication lines available to the moving body 100 and transmits the transmission target data by using the selected one communication line. It can be said that the cost-oriented selection mode MS1 is the most excellent communication mode from a viewpoint of low cost.
The quality-oriented selection mode MS2 selects one communication line with the highest communication quality from the communication lines available to the moving body 100 and transmits the transmission target data by using the selected one communication line. Here, examples of the communication quality include a communication bandwidth (communication speed, bit rate), radio wave intensity, round trip time (RTT), bit error rate, and the like. The communication quality may be any of a real-time measured value, an estimated value, and a predicted value based on a past communication result database. It can be said that the quality-oriented selection mode MS2 is a communication mode having a good balance of communication quality and low cost.
The communication controller 22 of the second communication device 20 on the receiving side may receive the same packets via multiple communication lines. In this case, the communication controller 22 selects a same packet received earliest and discards another same packet received later. For example, the communication controller 12 on the transmitting side gives identification information (e.g. an identification number) in a header of each transmission packet. The communication controller 22 on the receiving side grasps a reception history of each packet based on the identification information in the header of each received packet. Then, the communication controller 22 selects one received earliest and discards another received later among the same packets received via the multiple communication lines.
As described above, in the case of the redundant transmission mode MR, the same packets are simultaneously transmitted in parallel via multiple communication lines. Therefore, high communication reliability is achieved, and a communication delay is reduced as much as possible. In other words, the redundant transmission mode MR is excellent in terms of high reliability and low latency. However, since the multiple communication lines are used at the same time, the cost increases.
2-3. Split transmission Mode
As described below, the inventor of the present application has studied the mode selection process in detail.
First, there is a general tendency that developers desire to increase throughput as much as possible. In other words, the developers tend to be orientated toward achieving high throughput using the split transmission mode MD. However, a viewpoint of the developer does not necessarily coincide with a viewpoint of a user. Users do not necessarily desire to increase the throughput going so far as paying a high communication fee. Moreover, in an area where only a single communication line is available, the split transmission mode MD cannot be used (see
Regarding the communication between the moving body 100 such as a vehicle and a robot and the external device 200, it is considered that there is a need for reducing the communication cost as much as possible in a wider area. Meanwhile, depending on an environment in which the moving body 100 is placed, it is considered that there is also a need for highly reliable communication. It is important to appropriately balance low costs and high reliability in light of such needs.
In view of the above, according to the present embodiment, the “line selection mode MS” and the “redundant transmission mode MR” are mainly used. The mode selection process (Step S100) according to the present embodiment will be described below with reference to
In Step S110, the communication controller 12 acquires environmental information ENV and communication line information CLN. The environmental information ENV indicates an environment in which the moving body 100 is placed. A concrete example of the environmental information ENV will be described later. The communication line information CLN indicates communication lines currently available to the moving body 100, and the costs and communication qualities of the communication lines. Examples of the communication quality include a communication bandwidth (communication speed, bit rate), radio wave intensity, RTT, a bit error rate, and the like. The communication quality may be any of a real-time measured value, an estimated value, and a predicted value based on a past communication result database.
In Step S120, the communication controller 12 executes a “determination process” that determines whether or not reliable communication is necessary. Whether or not to give priority to the reliable communication also depends on the environment in which the moving body 100 is placed. Therefore, the communication controller 12 determines whether or not the reliable communication is necessary based on the environmental information ENV.
In a first example, the environmental information ENV indicates an “hour” (e.g., morning, noon, evening, and night) at a position where the moving body 100 is present. For example, when the hour is evening or night, the communication controller 12 determines that the reliable communication is necessary. Otherwise, the communication controller 12 determines that the reliable communication is not necessary.
In a second example, the environmental information ENV indicates “brightness” recognized by the moving body 100. For example, the brightness is low during night, in a tunnel, and in a backlight condition. For example, in a case of a dark condition in which the brightness is less than a threshold, the communication controller 12 determines that the reliable communication is necessary. On the other hand, in a case of a bright condition in which the brightness is equal to or higher than the threshold, the communication controller 12 determines that the reliable communication is not necessary.
In a third example, the environmental information ENV indicates a “weather condition” (e.g., sunny, cloudy, rainy, foggy, snowy) at a position where the moving body 100 is present. For example, when the weather condition is any of rainy, foggy, and snowy, the communication controller 12 determines that the reliable communication is necessary. Otherwise, the communication controller 12 determines that the reliable communication is not necessary.
In a fourth example, the environmental information ENV indicates an “object density” around the moving body 100. The object density indicates how dense objects such as people and other vehicles are around the moving body 100. For example, in a case of a high-density area (e.g., a shopping street) where the object density is equal to or higher than a threshold, the communication controller 12 determines that the reliable communication is necessary. On the other hand, in a case of a low-density area where the object density is less than the threshold, the communication controller 12 determines that the reliable communication is not necessary.
In a fifth example, the environmental information ENV indicates a “traffic scene” in which the moving body 100 is placed. Here, a case where the moving body 100 performs automated driving will be considered in particular. During the automated driving, there is a possibility that the moving body 100 requests a remote operator for a remote support, depending on the traffic scene in which the moving body 100 is placed. The remote support includes: (1) “recognition/decision support” in which the remote operator temporarily performs recognition or action decision instead of the moving body 100; and (2) “remote driving” in which the remote operator remotely drives (operates) the moving body 100. For example, there is a possibility that the moving body 100 requests the remote operator for the recognition/decision support at an intersection, a road construction section, a section where there is guidance by a guide person, and the like. On the other hand, in a traffic scene in which continuing the automated driving is impossible (for example, a complicated road structure, outside an ODD (Operational Design Domain), or the like), the moving body 100 requests the remote operator for the remote driving. In the case of the traffic scene requiring the remote driving, the communication controller 12 determines that the reliable communication is necessary. On the other hand, in a case of a traffic scene not requiring the remote driving, the communication controller 12 determines that the reliable communication is not necessary.
In a sixth example, the environmental information ENV indicates a “speed” of the moving body 100. For example, in a high-speed state in which the speed is equal to or higher than a threshold, the communication controller 12 determines that the reliable communication is necessary. On the other hand, when the speed is lower than the threshold, the communication controller 12 determines that the reliable communication is not necessary.
Returning to
On the other hand, in Step S140, the communication controller 12 selects the “line selection mode MS (see
In Step S141, the communication controller 12 recognizes, based on the communication line information CLN, a communication line with the lowest cost among the communication lines available to the moving body 100. It is assumed here that the communication line with the lowest cost is the first communication line C1. The communication controller 12 determines, based on the communication line information CLN, whether or not a communication quality of the first communication line C1 satisfies a predetermined level. For example, the communication controller 12 determines whether or not a throughput of the first communication line C1 is equal to or higher than a predetermined threshold. When the communication quality of the first communication line C1 satisfies the predetermined level (Step S141; Yes), the processing proceeds to Step S142. On the other hand, when the communication quality of the first communication line C1 does not satisfy the predetermined level (Step S141; No), the processing proceeds to Step S143.
In Step S142, the communication controller 12 selects the “cost-oriented selection mode MS1” from the plurality of communication modes.
In Step S143, the communication controller 12 selects the “quality-oriented selection mode MS2” from the plurality of communication modes.
As described above, according to the present embodiment, the plurality of communication modes include the line selection mode MS that is low-cost and the redundant transmission mode MR that is highly reliable and low-latency. Whether or not to give priority to the reliable communication depends on the environment in which the moving body 100 is placed. Therefore, whether or not the reliable communication is necessary is determined based on the environmental information ENV indicating the environment in which the moving body 100 is placed. When it is determined that the reliable communication is necessary, the redundant transmission mode MR is actively selected. On the other hand, when it is determined that the reliable communication is not necessary, the line selection mode MS is actively selected. The redundant transmission mode MR is selected only when the reliable communication is necessary, and the line selection mode MS is selected in the other cases, which can prevent an unnecessary increase in communication cost. That is, according to the present embodiment, it is possible to appropriately balance high reliability and low costs in the communication between the moving body 100 and the external device 200.
It should be noted that according to the related arts disclosed in the above-mentioned Patent Literatures, decrease in communication state and communication quality is taken into consideration, but the environment in which the moving body 100 is placed is not taken into consideration. In the prior art, the line selection mode MS or the redundant transmission mode MR is never selected according to the environment in which the moving body 100 is placed.
The first communication device 10 communicates with the external device 200 outside the moving body 100. For example, the first communication device 10 communicates with the remote support device 200A (see
The sensor group 110 includes a recognition sensor, a state sensor, a position sensor, and the like. The recognition sensor recognizes (detects) a situation around the moving body 100. Examples of the recognition sensor include the camera 111 (see
The control device 120 controls the moving body 100. The control device 120 includes one or more processors 130 (hereinafter simply referred to as a processor 130) and one or more memory devices 140 (hereinafter simply referred to as a memory device 140). The processor 130 executes a variety of processing. For example, the processor 130 includes a central processing unit (CPU). The memory device 140 stores a variety of information necessary for the processing by the processor 130. Examples of the memory device 140 include a volatile memory, a nonvolatile memory, a hard disk drive (HDD), a solid state drive (SSD), and the like. The control device 120 may include one or a plurality of electronic control units (ECUs).
A control program 150 is a computer program that is executed by the processor 130. The functions of the control device 120 are implemented by the processor 130 executing the control program 150. The control program 150 is stored in the memory device 140. The control program 150 may be recorded on a non-transitory computer-readable recording medium.
The control device 120 uses the sensor group 110 to acquire the environmental information ENV indicating the environment in which the moving body 100 is placed. The environmental information ENV is stored in the memory device 140. For example, the environmental information ENV includes surrounding situation information, state information, position information, and the like.
The surrounding situation information is information indicating the situation around the moving body 100 and is acquired by the recognition sensor. For example, the surrounding situation information includes the image IMG captured by the camera 111. As another example, the surrounding situation information may include point cloud information acquired by the LIDAR.
The surrounding situation information further includes object information regarding an object around the moving body 100. Examples of the object include a pedestrian, a bicycle, another vehicle (a preceding vehicle, a following vehicle, a parked vehicle, and the like), a road structure (a white line, a crosswalk, a curb, a guardrail, and the like), a traffic light, a sign, a fallen object, and the like. The object information indicates a relative position and a relative speed of the object with respect to the moving body 100. For example, analyzing the image IMG captured by the camera makes it possible to identify an object and to calculate a relative position of the object. It is also possible to identify an object and to acquire a relative position and a relative speed of the object on the basis of the point cloud information obtained by the LIDAR. The object information may include a moving direction and a moving speed of the object.
The surrounding situation information may include the hour (e.g., morning, noon, evening, and night) at the position where the moving body 100 is present. For example, the hour is recognized by analyzing the image IMG captured by the camera 111.
The surrounding situation information may include the brightness recognized by the moving body 100. The brightness is acquired by analyzing the image IMG captured by the camera 111. For example, the brightness is low during night, in a tunnel, and in a backlight condition.
The surrounding situation information may include the weather condition (e.g., sunny, cloudy, rainy, foggy, snowy) at the position where the moving body 100 is present. The weather condition is acquired, for example, by analyzing the image IMG captured by the camera 111. As another example, rain and snow can be detected based on laser reflectivity in the LIDAR measurement.
The surrounding situation information may include the object density around the moving body 100. The object density is an index indicating how dense objects such as people and other vehicles are around the moving body 100. The object density can be calculated based on the object information described above.
The surrounding situation information may include the traffic scene in which the moving body 100 is placed (e.g., an intersection, a roadwork section, guidance by a guide, a complex road structure, etc.). The traffic scene can be recognized on the basis of the object information described above.
The state information is information indicating the state of the moving body 100 and is detected by the state sensor. Examples of the state of moving body 100 include a speed, an acceleration, a yaw rate, a steering angle, and the like.
The state information may include a current driving mode (automated driving/remote driving/manual driving) of the moving body 100. The state information may indicate whether the moving body 100 requires the remote driving (i.e, whether it is impossible to continue the automated driving).
The position information is information indicating the position of the moving body 100 and is acquired by the position sensor. Further, highly accurate position information may be acquired by performing a well-known self-position estimation processing (localization) using the object information.
The actuator 160 is a device for moving the moving body 100. The control device 120 moves the moving body 100 by controlling the actuator 160.
For example, when the moving body 100 is a vehicle, the actuator 160 is a travel device that causes the vehicle to travel. The travel device includes a steering device, a drive device, and a braking device. For example, the steering device includes an electric power steering (EPS) device. Examples of the drive device include an engine, an electric motor, an in-wheel motor, and the like. The control device 120 executes vehicle travel control including steering control, driving control, and braking control by controlling the travel device.
The control device 120 may perform automated driving control based on the environmental information ENV. More specifically, the control device 120 generates a travel plan based on the environmental information ENV. Examples of the travel plan include maintaining a current travel lane, making a lane change, turning right or left, avoiding an obstacle, and the like. Further, the control device 120 generates, based on the environmental information ENV, a target trajectory necessary for the vehicle to travel in accordance with the travel plan. The target trajectory includes a target position and a target velocity. Then, the control device 120 performs the vehicle travel control so that the vehicle follows the target trajectory.
When the remote support is performed (see
The environmental information ENV, the communication line information CLN, and policy information POL are stored in the memory device 14. The environmental information ENV indicates the environment in which the moving body 100 is placed. The communication line information CLN indicates communication lines currently available to the moving body 100, and the costs and communication qualities of the communication lines. The policy information POL indicates the conditions under which the reliable communication is required as exemplified in
A communication control program 15 is a computer program executed by the processor 13. The functions of the communication controller 12 are implemented by the processor 13 executing the communication control program 15. The communication control program 15 is stored in the memory device 14. The communication control program 15 may be recorded on a non-transitory computer-readable recording medium.
It should be noted that the communication controller 12 shown in
The environmental information acquiring unit 16 acquires the environmental information ENV from the control device 120 (
The communication line information acquiring unit 17 generates the communication line information CLN based on a result of communication by the communication unit 19 (
The communication mode selection unit 18 holds the policy information POL. The communication mode selection unit 18 executes the mode selection process that selects one of the plurality of communication modes based on the environmental information ENV, the policy information POL, and the communication line information CLN (
The communication unit 19 receives the transmission target data DAT. The transmission target data DAT may be streaming data. Based on the communication mode selected by the communication mode selection unit 18, the communication unit 19 selects a communication line to be used and transmits the transmission target data DAT to the external device 200 (
The plurality of communication modes of the communication controller 12 may include a “combination mode MC” based on the video coding standard H.264/SVC. The combination mode MC is a combination of the redundant transmission mode MR and the line selection mode MS.
The communication controller 12 transmits the high-priority data DAT-H of the base layer LB based on the redundant transmission mode MR and transmits the low-priority data DAT-L of the enhancement layer LE based on the line selection mode MS. For example, the communication controller 12 selects two communication lines in descending order of communication quality based on the communication line information CLN. Then, the communication controller 12 transmits the high-priority data DAT-H of the base layer LB in the redundant transmission mode MR by using the selected two communication lines. Further, the communication controller 12 transmits the low-priority data DAT-L of the enhancement layer LE in the line selection mode MS by using another one communication line. Whether to select the cost-oriented selection mode MS1 or the quality-oriented selection mode MS2 is determined in the same manner as the method shown in
According to the combination mode MC, it is possible to improve video quality at low cost while at least ensuring continuity of video reproduction.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-018829 | Feb 2022 | JP | national |
