Communication control device and communication control method

Abstract

To perform switching of communication methods at a proper frequency.SOLUTION: A communication control device comprises: a plurality of communication units respectively corresponding to a plurality of communication methods; and a communication unit selection unit which selects the communication unit to be used for transmission / reception of prescribed data from the plurality of communication units. The device acquires and stores the communication state including a delay time for each of the plurality of communication units, refers to the storage unit, compares the delay time of the communication unit being selected being the communication unit selected by the communication unit selection unit in a time-series manner, determines variation in the delay time, refers to the storage unit when the delay time of the communication unit being selected indicates a prescribed increase tendency, and determines the communication unit to be used for transmission / reception of the prescribed data as the switching destination communication unit from the communication state of each communication unit. The communication unit selection unit selects the switching destination communication unit as the new communication unit being selected when a switching determination unit determines the switching destination communication unit.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a communication control device and a communication control method.

Background Art

[0002] Conventionally, a technique for switching and using a plurality of communication methods is known. For example, Patent Document 1 describes that "a communication device is a communication device mounted on a mobile body, and communicates with an external device using communication of a first communication method or communication of a second communication method different from the first communication method. A communication unit, a determination unit that dynamically determines the communication priority of the own device for each access point, and information including information indicating the communication priority determined by the determination unit and mobile body information regarding the mobile body are transmitted to the communication unit for each access point. A communication control unit to be transmitted, and the communication control unit causes the communication unit to communicate with the external device according to the determined communication priority, and when communication is switched, causes the communication unit to communicate according to the determined communication priority."

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A communication device according to the conventional technology can switch the communication method based on the communication delay time, throughput, communication speed, traffic volume, bandwidth utilization rate, number of error packets, number of lost packets, and the like. However, in the conventional technology, consideration is not given to performing the switching before the communication quality goes out of the allowable range and reducing the switching frequency of the communication method.

[0005] For example, consider a scenario where a vehicle transmits information about its own status and surrounding conditions to a user's mobile device, the user operates the device to check the vehicle's status, and sends driving instructions as needed. In such a case, if the transmission / reception delay becomes large, there may not be enough time to control the vehicle. Therefore, it is necessary to switch to another communication method before the delay exceeds an acceptable range. However, since switching communication methods itself can cause delays and a decrease in communication quality, it is desirable to minimize the frequency of communication method switching as much as possible.

[0006] Therefore, the present invention aims to enable switching of communication methods at an appropriate frequency. [Means for solving the problem]

[0007] To achieve the above objective, one representative communication control device of the present invention comprises: a plurality of communication units corresponding to a plurality of communication methods; a communication unit selection unit that selects a communication unit from the plurality of communication units to be used for sending and receiving predetermined data; a communication status acquisition unit that acquires the communication status, including delay time, for each of the plurality of communication units; a storage unit that stores the communication status acquired by the communication status acquisition unit; a delay time determination unit that refers to the storage unit and compares the delay time of the selected communication unit, which is the communication unit selected by the communication unit selection unit, in a time series to determine any change in delay time; and a switching determination unit that, if the delay time of the selected communication unit shows a predetermined increasing trend as a result of the determination by the delay time determination unit, refers to the storage unit and determines from the communication status of each communication unit that the communication unit to be used for sending and receiving the predetermined data should be determined as the switching destination communication unit, wherein the communication unit selection unit selects the switching destination communication unit as the new selected communication unit when the switching determination unit has determined the switching destination communication unit. [Effects of the Invention]

[0008] According to the present invention, the communication method can be switched at an appropriate frequency. Other problems, configurations, and effects will be clarified by the following description of embodiments. [Brief explanation of the drawing]

[0009] [Figure 1] An explanatory diagram of the vehicle control according to Example 1. [Figure 2] A diagram showing the configuration of a communication control device. [Figure 3] A flowchart illustrating the process for automatic parking. [Figure 4] A flowchart showing the details of the communication status comparison. [Figure 5] An explanatory diagram for determining delay fluctuations. [Figure 6] Explanation of delay, short-term fluctuations, and long-term fluctuations. [Modes for carrying out the invention]

[0010] The following examples will be described with reference to the drawings. [Examples]

[0011] Figure 1 is an explanatory diagram of the vehicle control according to Embodiment 1. The vehicle 10 shown in Figure 1 is equipped with a communication control device 20. The communication control device 20 is an electronic control unit (ECU) and can communicate with a terminal 40 carried by the user of the vehicle 10. The communication control device 20 also has an automatic parking function that automatically performs driving control of the vehicle related to parking.

[0012] When a user drives vehicle 10, exits the vehicle at the entrance or exit of a parking lot, and activates the automatic parking function, vehicle 10 automatically drives to a parking space and performs driving control to park within the parking space. While this automatic driving control is being performed, the communication control device 20 transmits information about the vehicle's driving status to terminal 40. This information about the vehicle's driving status includes information about the state of vehicle 10 itself (such as vehicle speed) and information about the state of the area around vehicle 10 (such as radar detection results and camera images).

[0013] The user can check the vehicle's driving status using terminal 40. They can then control the vehicle's movement as needed. For example, if the user determines, by checking the surrounding images, that an emergency stop is necessary, they can perform an emergency stop operation on terminal 40. Terminal 40 receives the emergency stop operation and sends an instruction to the vehicle control device 20 requesting an emergency stop. Upon receiving the instruction to stop an emergency stop, the communication control device 20 prioritizes the instruction from terminal 40 over automatic driving control, and the vehicle 10 stops.

[0014] In this manner, the communication control device 20 transmits the vehicle driving status to the terminal 40 and receives driving control operations from the terminal 40. Here, the communication control device 20 is equipped with multiple communication units, each corresponding to a different communication method. If the communication control device 20 is capable of communicating with the terminal 40 using multiple communication methods, it is desirable that the transmission of the vehicle driving status and the reception of driving control operations be performed using the communication method with the best communication quality. Among the communication quality aspects, transmission and reception delay is a crucial factor. If the transmission and reception delay becomes large, the user will not have enough time to make decisions or take action, which could lead to situations where the user is unable to perform an emergency stop operation in time.

[0015] The communication control device 20 selects a communication method with low latency from among several communication methods and sends and receives data related to vehicle control with the terminal 40. However, latency is not constant. If the latency of the selected communication method fluctuates and, as a result, falls outside the acceptable range, it may become impossible to control the vehicle in time. Therefore, it is necessary to switch communication methods before the latency falls outside the acceptable range. On the other hand, the switching of communication methods itself can also be a cause of latency and deterioration of communication quality, so it is desirable to minimize the frequency of switching communication methods as much as possible.

[0016] Therefore, the communication control device 20 appropriately performs communication to check the communication quality of communication methods other than the selected one, and if there is an increasing trend in the delay time of the selected communication method, it determines the quality of each communication method and switches the communication method if necessary.

[0017] Specifically, the communication control device 20 compares the delay times of the selected communication method in chronological order to determine the variation in the delay time (step S11). If there is no tendency for the delay time of the selected communication method to increase (step S12; No), the communication control device 20 maintains the current communication method (step S13) and returns to step S11. When there is a tendency for the delay time of the selected communication method to increase (step S12; Yes), the communication control device 20 determines the quality of each communication method and selects a communication method (if the selected communication method is different from the currently selected communication method, it executes a switch to another communication method) (step S14), and returns to step S11 with the selected communication method as the new selected communication method.

[0018] In this way, the communication control device 20 can switch the communication method before the delay time exceeds the allowable range by evaluating the increasing tendency of the delay time. In addition, since the communication control device 20 maintains the currently selected communication method if the increasing tendency is not significant, the switching frequency of the communication method can be suppressed. In evaluating the increasing tendency of the delay time, fluctuations in a short period, fluctuations in a long period, the magnitude of the delay time itself, etc. can be used as indicators, and the details of this point will be described later.

[0019] FIG. 2 is a configuration diagram showing the configuration of the communication control device 20. The communication control device 20 is mounted on the vehicle 10. Further, the communication control device 20 is connected to one or more cameras 11, one or more radars 12, a drive control unit 13, etc. The camera 11 images the surroundings of the vehicle 10. The radar 12 detects an object existing around the vehicle 10. The radar 12 may be a radio wave type or a sonic wave type sonar. It may also be a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging). The drive control unit 13 is a group of units that perform vehicle acceleration / deceleration control, steering control, etc.

[0020] The communication control device 20 includes, inside it, communication units 21 to 23, a vehicle determination unit 31, a vehicle control unit 32, a position acquisition unit 33, a communication status acquisition unit 34, a memory unit 35, a delay time determination unit 36, a switching determination unit 37, and a communication unit selection unit 38.

[0021] The communication units 21 to 23 are communication units with different communication methods respectively. The communication unit 21 performs communication using Bluetooth (registered trademark), UWB (Ultra Wideband), etc. The communication unit 22 performs communication using a mobile communication system. Mobile communication can be further distinguished, for example, as the fourth generation (4G), the fifth generation (5G), etc. The communication unit 23 performs communication using a wireless LAN (Local Area Network).

[0022] The communication unit 21 can directly communicate with the terminal 40. The communication unit 22 can communicate with the user's terminal 40 and the server 60 via the base station 51. The communication unit 23 can communicate with the terminal 40 and the server 60 via the router 52. The server 60 manages parking lot data indicating the arrangement of parking spaces in the parking lot and vacancy status data indicating the vacancy status of each parking space.

[0023] The vehicle determination unit 31 acquires information on obstacles existing around the vehicle 10. Specifically, the vehicle determination unit 31 identifies obstacles from the image of the camera 11 and the output of the radar 12. The information on obstacles is one of the data indicating the state of the vehicle.

[0024] The position acquisition unit 33 acquires the position information of the vehicle 10. For example, a global positioning system can be used to acquire the position information. The position information of the vehicle 10 is one of the data indicating the state of the vehicle.

[0025] The vehicle control unit 32 acquires the vehicle speed, the control state of acceleration and deceleration, the steering state, etc. from the drive control unit 13, and uses them as one of the data indicating the state of the vehicle. The vehicle control unit 32 controls the movement of the vehicle 10 using the determination result from the vehicle determination unit 31, the position information acquired by the position acquisition unit 33, the status of the vehicle itself acquired from the drive control unit 13, and so on. When the vehicle control unit 32 receives data from the terminal 40 indicating instructions for the vehicle 10's movement, it prioritizes the instructions from the terminal 40. For example, if the vehicle control unit 32 is in the process of controlling the vehicle to park in a parking space and receives a stop instruction from the terminal 40, it will control the vehicle 10 to stop. In addition, if the vehicle control unit 32 is controlling the vehicle 10's movement and receives information about a parking space from the terminal 40, it can also start control to park in the received parking space.

[0026] The communication unit selection unit 38 selects a communication unit from among the multiple communication units 21 to 23 to be used for sending and receiving data related to vehicle control. The communication unit selected by the communication unit selection unit 38 is called the selected communication unit. The data related to vehicle control includes data indicating the status of the vehicle and data indicating instructions for the vehicle 10 to move.

[0027] The communication status acquisition unit 34 acquires the communication status for each of the multiple communication units 21 to 23 at predetermined time intervals. Communication status acquisition is performed for both the selected communication unit and the other communication units. Communication status includes delay time, signal strength, noise, etc. The memory unit 35 stores the communication status acquired by the communication status acquisition unit in association with the communication units 21 to 23.

[0028] The delay time determination unit 36 ​​refers to the storage unit 35 and compares the delay times of the selected communication unit over time to determine any changes in delay time. It also compares the delay times of other communication units over time to determine any changes in delay time. If the delay time determination unit 36 ​​determines that the delay time of the selected communication unit is showing a predetermined increasing trend, the switching determination unit 37 refers to the storage unit 35 and determines, based on the communication status of each communication unit, which communication unit should be used for sending and receiving predetermined data as the switching destination communication unit. The communication unit selection unit 38 selects the target communication unit as the new selected communication unit when the switching determination unit 37 determines the target communication unit.

[0029] Figure 3 is a flowchart showing the automatic parking process procedure of Embodiment 1. The communication control device sequentially executes the following steps S101 to S111 when performing the automatic parking process. Step S101: Upon receiving instructions from terminal 40, the vehicle control unit 32 starts automatic parking of the vehicle 10 on its own. In addition to instructions from terminal 40, it is also possible to start the process using a remote key, timer settings, etc.

[0030] Step S102: Communication units 21-23 each perform connectivity checks and determine communication delays. Specifically, communication units 21-23 transmit connectivity data to terminal 40 for connectivity checks. The connectivity data contains transmission time data internally. In step S103, communication units 21 to 23 each receive a response to the communication data transmitted in step S102. The communication status acquisition unit 34 calculates the delay time from the difference between the received response time and the transmitted time data and stores it in the storage unit 35.

[0031] In step S104, the delay time determination unit 36 ​​refers to the multiple delay times stored in the storage unit 35 and determines whether the fluctuation in delay time shows a predetermined increasing trend, etc. Step S105 The communication status acquisition unit 34 acquires the signal strength of the communication method from the response to the communication data for each of the communication units 21 to 23 and stores it in the storage unit 35. In step S106, the communication status acquisition unit 34 acquires the amount of noise in the communication method from the response to the communication data for each of the communication units 21 to 23 and stores it in the storage unit 35.

[0032] In step S107, the switching determination unit 37 compares the communication status based on the increasing trend of delay time, signal strength, noise level, etc., and determines the switching destination communication unit. In the initial state, the currently selected communication unit has not been determined, so the switching destination communication unit determined in this step becomes the initial currently selected communication unit. Subsequently, the switching destination communication unit is selected when the delay time of the currently selected communication unit shows a predetermined increasing trend. In step S108, the communication unit selection unit 38 selects a communication unit to be used for sending and receiving data related to vehicle control, and designates it as the selected communication unit. Step S109 The vehicle determination unit 31 and the vehicle control unit 32 use the selected communication unit to send and receive data related to vehicle control. Step S110 The vehicle control unit 32 determines whether automatic parking is complete or not. If automatic parking is not complete, the process returns to step S101. If automatic parking is complete, the process proceeds to step S111. Step S111: The communication control device 20 terminates the automatic parking process.

[0033] Figure 4 is a flowchart detailing the communication state comparison shown in Figure 3. When the communication state comparison starts (step S201), the delay time determination unit 36 ​​determines whether the delay of the selected communication unit is within a predetermined standard (step S202). Specifically, the delay time determination unit 36 ​​determines that the delay is within the standard if the short-term fluctuation, long-term fluctuation, and delay amount are all below the standard value. Short-term fluctuation is the fluctuation of the delay time over a short period of time. Long-term fluctuation is the fluctuation of the delay time over a long period of time. Delay amount is the magnitude of the delay time. If any of the short-term fluctuation, long-term fluctuation, or delay amount exceeds the standard value, it is determined that the delay is not within the predetermined standard and is showing a predetermined increasing trend.

[0034] If the delay of the selected communication unit is within the standard range (step S202; Yes), the communication unit selection unit 38 continues with the currently selected communication unit (step S203) and ends the communication status comparison (step S214).

[0035] If the delay of the selected communication unit is not within the standard (Step S202; No), the switching determination unit 37 determines whether the delays of other communication units are within the standard (Step S204). If there is a communication unit whose delay is within the standard (Step S204; Yes), the switching determination unit 37 selects a communication unit from among the communication units whose delay is within the standard that shows little tendency for delay increase, and sets it as the switching destination communication unit (Step S205). Then, the communication unit selection unit 38 switches the selected communication unit by setting the switching destination communication unit as the new selected communication unit (Step S206), and ends the communication status comparison (Step S214).

[0036] If there are no communication units with a delay within the standard (Step S204; No), the switching determination unit 37 refers to the signal strength of other communication units stored in the memory unit 35 (Step S207) and determines whether the signal strength is above the threshold (Step S208). If there is a communication unit with a signal strength above the threshold (Step S208; Yes), the switching determination unit 37 selects a communication unit with a high signal strength from among the communication units with a signal strength above the threshold and sets it as the switching destination communication unit (Step S209). Then, the communication unit selection unit 38 switches the selected communication unit by setting the switching destination communication unit as the new selected communication unit (Step S210), and ends the communication state comparison (Step S214).

[0037] If there are no communication units with a signal strength above the threshold (step S208; No), the switching determination unit 37 refers to the noise of other communication units stored in the memory unit 35 (step S211), selects a communication unit with low noise, and sets it as the switching destination communication unit (step S212). Then, the communication unit selection unit 38 switches the currently selected communication unit by setting the switching destination communication unit as the new currently selected communication unit (step S213), and ends the communication state comparison (step S214).

[0038] Figure 5 is an explanatory diagram for determining delay fluctuations. In Figure 5, the delay time is evaluated on an 11-point scale from 0 to 10, with "0" representing the value when there is no delay and "10" representing the value when the delay is at its maximum. Also, t0 is the evaluation value of the delay time obtained at the most recent timing, and t1 is the evaluation value of the delay time obtained at the previous timing.

[0039] First, in the initial state, the evaluation values ​​for t0 to t4 are all "0". After the first evaluation of the delay time, t0 becomes "1", while t1 to t4 remain "0". In the second evaluation of the delay time, the previous evaluation values ​​shift back by one, and t0 becomes "4". In the third evaluation of the delay time, the previous evaluation values ​​shift back by one, and t0 becomes "3". In the fourth evaluation of the delay time, the previous evaluation values ​​shift back by one, and t0 becomes "7". Therefore, at the time of the fourth evaluation of the delay time, t1 is "3", t2 is "4", t3 is "1", and t4 is "0".

[0040] The delay time determination unit 36 ​​sums up the increases and decreases in delay time, and if the sum exceeds a baseline value, it determines that the delay time of the selected communication unit is showing a predetermined increasing trend. In Figure 5, The sum is calculated as (t0-t1)+(t1-t2)+(t2-t3)+(t3-t4). This sum is compared with the reference value "5", so when the sum exceeds 5, the delay time determination unit 36 ​​determines that the delay time is on an increasing trend.

[0041] Figure 6 is an explanatory diagram of delay amount, short-term variation, and long-term variation. The delay amount corresponds to the evaluation value of delay in Figure 5. Short-term variation is the sum of the increase and decrease in delay time in Figure 5. Short-term variation calculates the difference with the delay time obtained at the previous timing, while long-term variation calculates the difference with the delay time obtained at the timing four times prior. By evaluating the difference in delay time at different periods in this way, it is possible to achieve both a rapid response to a steep increase in delay time and a highly accurate response to a slow increase in delay time.

[0042] As described above, the disclosed communication control device 20 includes a plurality of communication units 21 to 23 corresponding to a plurality of communication methods, a communication unit selection unit 38 that selects a communication unit from the plurality of communication units to be used for sending and receiving predetermined data, a communication status acquisition unit 34 that acquires the communication status, including delay time, for each of the plurality of communication units, a storage unit 35 that stores the communication status acquired by the communication status acquisition unit, a delay time determination unit 36 ​​that refers to the storage unit 35 and compares the delay time of the selected communication unit, which is the communication unit selected by the communication unit selection unit 38, in a time series and determines the change in delay time, and a switching determination unit 37 that, if the delay time of the selected communication unit shows a predetermined increasing trend as a result of the determination by the delay time determination unit 36, refers to the storage unit 35 and determines the communication unit to be used for sending and receiving the predetermined data from the communication status of each communication unit 21 to 23 as the switching destination communication unit, and the communication unit selection unit 38 selects the switching destination communication unit as the new selected communication unit when the switching determination unit 37 determines the switching destination communication unit. With this configuration and operation, the communication control device 20 can achieve both early switching and reduced switching frequency, enabling it to switch communication methods at an appropriate frequency.

[0043] Furthermore, the disclosed communication control device 20 is an in-vehicle device mounted on the vehicle 10. The predetermined data is data relating to the control of the vehicle, and the selected communication unit transmits data indicating the status of the vehicle to a predetermined terminal and receives data from the terminal indicating instructions for driving the vehicle. Therefore, when controlling the vehicle 10 remotely, it is possible to prevent situations where the control of the vehicle 10 cannot be completed in time.

[0044] Furthermore, according to the disclosed communication control device 20, the communication status acquisition unit 34 acquires the delay time at predetermined intervals, the storage unit 35 stores the delay time at predetermined intervals for at least the selected communication unit, and the delay time determination unit 36 ​​sums up the increase or decrease in delay time over a predetermined period, and determines that the delay time of the selected communication unit shows a predetermined increasing trend if the sum exceeds a standard value. Therefore, it is possible to easily and effectively compare delay times over time.

[0045] Furthermore, according to the disclosed communication control device 20, the delay time determination unit 36 ​​determines the increasing trend using the sum of the increase and decrease in delay time during the first period and the sum of the increase and decrease in delay time during the second period. Therefore, it can respond to various increasing trends and accurately detect the increasing trend of the selected communication unit.

[0046] Furthermore, according to the disclosed communication control device 20, if there is a communication unit other than the selected communication unit that does not fall under the predetermined increasing trend, the switching determination unit 37 considers that communication unit as a candidate for the switching destination communication unit, and if there is no communication unit that does not fall under the predetermined increasing trend, it determines the candidate for the switching destination communication unit based on signal strength and / or noise. In this way, the communication control device 20 can determine the switching destination by comparing the increasing trend of delays of the communication units and performing communication data communication by other communication units in parallel with the predetermined data communication by the selected communication unit. If the switching destination cannot be determined based on the increasing trend of delays, the device can determine the switching destination communication unit using other evaluation indicators.

[0047] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are explained in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace or add configurations, not just delete them.

[0048] For example, the above embodiment illustrates a case where remote intervention is performed on automatic driving control. However, the present invention is not limited to automatic driving control and can be broadly applied to cases where a vehicle communicates with the outside world while in motion and receives intervention on its driving. For example, it can be applied to cases where information about the vehicle and its surroundings is transmitted to the outside world for the purpose of training or evaluating the driver, and instructions are given to the driver or intervention is performed on vehicle control. Specific examples include wireless training for obtaining a driver's license, evaluation of the driving skills of elderly drivers, and driving support at the request of the driver.

[0049] Furthermore, autonomous driving is not limited to parking; for example, it can be applied to the automatic driving control of passenger cars and buses on public roads, the driving control of vehicles via dispatch centers, and delivery. Moreover, it is not limited to vehicles; it can also be applied to the control of drones, the control of transport robots in factories, and the control of serving robots in restaurants. [Explanation of symbols]

[0050] 10: Vehicle, 11: Camera, 12: Radar, 13: Drive control unit, 20: Communication control device, 21-23: Communication unit, 31: Vehicle detection unit, 32: Vehicle control unit, 33: Position acquisition unit, 34: Communication status acquisition unit, 35: Memory unit, 36: Delay time determination unit, 37: Switching determination unit, 38: Communication unit selection unit, 40: Terminal, 51: Base station, 52: Router, 60: Server

Claims

1. Multiple communication units, each supporting multiple communication methods, A communication unit selection unit that selects a communication unit from the plurality of communication units to be used for sending and receiving predetermined data, Each of the aforementioned multiple communication units is provided with a communication status acquisition unit that acquires the communication status including the delay time, A storage unit that stores the communication status acquired by the aforementioned communication status acquisition unit, A delay time determination unit compares the delay times of the selected communication units, which are selected by the communication unit selection unit, in a time series, by referring to the memory unit, and determines the change in delay time. The system includes a switching determination unit that, if the delay time of the selected communication unit shows a predetermined increasing trend as a result of the determination by the delay time determination unit, refers to the storage unit and determines, based on the communication status of each communication unit, the communication unit to be used for sending and receiving the predetermined data as the switching destination communication unit, The communication unit selection unit selects the switching destination communication unit as the new selected communication unit when the switching determination unit determines the switching destination communication unit. If the delay time determination unit determines that the delay time of the selected communication unit shows a predetermined increasing trend, and there is a communication unit other than the selected communication unit that does not fall under the predetermined increasing trend, then that communication unit will be designated as a candidate for the switching destination communication unit. If there is no communication unit that does not fall under the predetermined increasing trend, then the switching destination communication unit will be designated as a candidate based on the signal strength and / or noise of the communication units other than the selected communication unit. A communication control device characterized by the following:

2. A communication control device according to claim 1, The US communication control unit is mounted in the vehicle. The predetermined data is data relating to the control of the vehicle, The selected communication unit transmits data indicating the status of the vehicle to a predetermined terminal and receives data from the terminal indicating instructions for the vehicle to drive.

3. A communication control device according to claim 1, The aforementioned communication status acquisition unit acquires the delay time at predetermined intervals, The storage unit stores the delay time for each predetermined time interval for at least the selected communication unit. The communication control device is characterized in that the delay time determination unit sums up the increase or decrease in delay time over a predetermined period, and determines that the delay time of the selected communication unit shows a predetermined increasing trend if the sum exceeds a reference value.

4. A communication control device according to claim 3, The communication control device is characterized in that the delay time determination unit determines the increasing trend using the total increase and decrease in delay time during the first period and the total increase and decrease in delay time during the second period.

5. A communication control method for a communication control device equipped with multiple communication units, each corresponding to a different communication scheme, A communication unit selection step of selecting a communication unit from the plurality of communication units to be used for sending and receiving predetermined data, For each of the aforementioned multiple communication units, a communication status acquisition step is performed to acquire the communication status, including the delay time. A storage step in which the communication status acquired in the communication status acquisition step is stored in the storage unit, A delay time determination step involves referring to the memory unit, comparing the delay times of the selected communication units (which are the communication units selected in the communication unit selection step) in a time series, and determining any changes in the delay time. If the result of the determination in the delay time determination step shows a predetermined increasing trend in the delay time of the selected communication unit, a switching determination step is performed in which the storage unit is referred to and the communication unit to be used for sending and receiving the predetermined data is determined as the switching destination communication unit based on the communication status of each communication unit. The switching step includes, if the switching destination communication unit is determined in the switching determination step, selecting the switching destination communication unit as the new selected communication unit, The switching determination step, if the delay time of the selected communication unit shows a predetermined increasing trend as a result of the determination in the delay time determination step, and if there is a communication unit other than the selected communication unit that does not fall under the predetermined increasing trend, then that communication unit is designated as a candidate for the switching destination communication unit. If there is no communication unit that does not fall under the predetermined increasing trend, then the candidate for the switching destination communication unit is determined based on the signal strength and / or noise of the communication units other than the selected communication unit. A communication control method characterized by the following:

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