JP2017135559A - On-vehicle communication system, portable equipment and communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle communication system, portable equipment and a communication method, capable of improving comfort.SOLUTION: In the on-vehicle communication system which performs radio communication between portable equipment and an on-vehicle device, the portable equipment includes: a transmitter unit which transmits a spread-spectrum modulated radio signal to the on-vehicle device; a receiver unit which receives, from the on-vehicle device, a response signal to the radio signal from the transmitter unit; first transmission control means which controls the transmitter unit to perform spread-spectrum modulation with a first spreading ratio to transmit the radio signal; determination means which determines whether or not the receiver unit could receive a response signal associated with the radio signal in a predetermined waiting time; second transmission control means which, when the determination means determines to be incapable of reception, performs spread-spectrum modulation with a second spreading ratio, which is higher than the first spreading ratio, to retransmit the radio signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an in-vehicle communication system, a portable device, and a communication method according to a remote start of a vehicle.

  In the technical field of improving the comfort of vehicles, remote start systems that instruct the start of operations such as engine start, air conditioning operation, etc. to remote, for example, vehicles parked in indoor parking lots from indoors at home have become widespread. Yes. Patent Document 1 discloses that a two-way communication is performed using a communication method such as spread spectrum between a portable device that is a portable device and a parent device that is a vehicle-mounted device, and air conditioning is activated by remote operation. Yes.

JP 2009-248626 A

  The communication between the portable device and the vehicle-mounted device generally uses a fixed band within a frequency band such as RF. However, the spread spectrum method is increasingly used to extend the communication distance. In the spread spectrum method, it is possible to communicate over long distances while maintaining the radio field intensity by increasing the spreading factor. However, when the spreading factor is high, the time for demodulation is longer than when the spreading factor is relatively low. Cost. Therefore, when realizing an answer-back function from an in-vehicle device on a portable device, when using a high spreading factor in a fixed manner in order to cope with a long distance, the time required for the answer-back becomes longer, and the user may feel uncomfortable. There is sex.

  This invention is made | formed in view of such a situation, and it aims at providing the vehicle-mounted communication system which can improve comfort, a portable device, and a communication method.

  An in-vehicle communication system according to an aspect of the present invention is an in-vehicle communication system that performs wireless communication between a portable device and an in-vehicle device, wherein the portable device transmits a spread spectrum modulated radio signal to the in-vehicle device. A reception unit that receives a response signal from the in-vehicle device with respect to the radio signal from the transmission unit, and a first transmission control unit that causes the transmission unit to perform spread modulation with a first spreading factor and transmit a radio signal A determination means for determining whether or not the response signal corresponding to the radio signal can be received by the reception unit within a predetermined waiting time; and when the determination means determines that the response signal cannot be received, And second transmission control means for retransmitting the radio signal by performing spread modulation with a high second spreading factor.

  A portable device according to one aspect of the present invention is a portable device that transmits and receives signals to and from a vehicle-mounted device, a transmission unit that transmits a spread spectrum modulated wireless signal to the vehicle-mounted device, and the wireless signal from the transmission unit A receiving unit that receives a response signal from the in-vehicle device, a first transmission control unit that causes the transmission unit to perform spread modulation with a first spreading factor and transmit a radio signal, and a response signal corresponding to the radio signal Determining means for determining whether or not the signal can be received by the receiving unit within a predetermined waiting time; and if the determining means determines that the signal cannot be received, spread modulation with a second spreading factor higher than the first spreading factor And second transmission control means for retransmitting the radio signal.

  A communication method according to an aspect of the present invention is a wireless signal communication method in an in-vehicle communication system including a portable device and an in-vehicle device each including a transmission unit and a reception unit that transmit and receive a spread spectrum modulated radio signal. The transmission unit has caused the transmission unit to perform modulation modulation with a first spreading factor to transmit a wireless signal, and has the reception unit received the response signal from the in-vehicle device for the transmitted wireless signal within a predetermined waiting time? If it is determined that the signal cannot be received, the radio signal is retransmitted from the transmitter by performing spread modulation with a second spreading factor larger than the first spreading factor.

  Note that the present application can be realized not only as an in-vehicle communication system, a portable device, and a communication method including such characteristic components, but also as a program for causing a computer to execute such characteristic steps. Can do. Moreover, it is realizable as a semiconductor integrated circuit which implement | achieves a part or all of a vehicle-mounted communication system, a portable device, and a communication method, or it can implement | achieve as another system containing a vehicle-mounted communication system and a portable device.

  According to the above, the spreading factor used in communication between the portable device and the vehicle-mounted device is appropriately changed as necessary, and the waiting time for the answer back can be shortened, and the comfort for the user is further improved. . In addition, the power consumption can be optimized by optimizing the standby time.

1 is an explanatory diagram illustrating an overview of an in-vehicle communication system according to Embodiment 1. FIG. 1 is a block diagram showing a configuration of an in-vehicle communication system in a first embodiment. 4 is a flowchart illustrating an example of a processing procedure performed between the portable device and the in-vehicle device according to the first embodiment. 10 is a flowchart illustrating another example of a processing procedure performed by the portable device in the first embodiment. 6 is a block diagram showing a configuration of an in-vehicle communication system in a second embodiment. FIG. 10 is a flowchart illustrating an example of a processing procedure performed by the portable device in the second embodiment. 6 is an explanatory diagram illustrating an example of content of learning data according to Embodiment 2. FIG.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described. Moreover, you may combine arbitrarily at least one part of embodiment described below.

  (1) An in-vehicle communication system according to the present invention is an in-vehicle communication system that performs wireless communication between a portable device and an in-vehicle device, wherein the portable device transmits a radio signal subjected to spread spectrum modulation to the in-vehicle device. A reception unit that receives a response signal from the in-vehicle device with respect to the radio signal from the transmission unit, and a first transmission control unit that causes the transmission unit to perform spread modulation with a first spreading factor and transmit a radio signal A determination means for determining whether or not the response signal corresponding to the radio signal can be received by the reception unit within a predetermined waiting time; and when the determination means determines that the response signal cannot be received, And second transmission control means for retransmitting the radio signal by performing spread modulation with a high second spreading factor.

  In the present application, the spreading factor is increased when a signal cannot be received by the in-vehicle device through communication using a relatively low spreading factor and a response signal cannot be received. The spreading factor used in communication between the portable device and the in-vehicle device is optimized as necessary.

  (2) The in-vehicle communication system according to the present invention determines whether or not a response signal corresponding to a radio signal retransmitted from the transmission unit by the second transmission control unit has been received by the reception unit within a second standby time. Second determination means for determining is further provided, and the second waiting time is longer than the predetermined waiting time.

  In the present application, since the length of the standby time for the answer back is set according to the spread rate, the standby time can be optimized and the power consumption of the portable device can be optimized.

  (3) In the in-vehicle communication system according to the present invention, the portable device stores a correspondence between a spreading factor when the response signal is received by the receiving unit and time information indicating a time when the response signal is received. A time determining means for determining whether or not the time indicated by the time information included in the correspondence stored in the storage unit coincides with the time when the wireless signal is spread and modulated by the transmission unit in the storage unit; And when the time determination means determines that they match, the spreading factor corresponding to the time information is used as the first spreading factor.

  In the present application, the initial value of the spreading factor is set with reference to learning data of the used spreading factor with respect to time. This makes it possible to shorten the standby time and optimize power consumption.

  (4) In the in-vehicle communication system according to the present invention, the in-vehicle device adds the vehicle position information to the response signal and transmits the position signal, and transmits the position information to the portable device when the door is locked. The portable device further includes: a correspondence storage unit that stores a spreading factor when the reception unit receives the response signal, and a correspondence of the vehicle position information added to the response signal; A host vehicle position storage unit that stores the host vehicle position information transmitted from the position transmission unit, and a host vehicle position information stored in the host vehicle position storage unit when the transmission unit performs spread modulation on a radio signal; Position determination means for determining whether or not the time indicated by the vehicle position information included in the correspondence stored in the correspondence storage unit matches, and when the one judgment means determines that the time matches, The diffusion rate corresponding to the vehicle position information is set to the first Used as a Chiritsu.

  In the present invention, the initial value of the spreading factor is set with reference to the learning data of the used spreading factor for the position of the vehicle. This makes it possible to shorten the standby time and optimize power consumption.

  (5) In the in-vehicle communication system according to the present invention, the portable device transmits a signal requesting start of an engine or a driving battery system and an operation of air conditioning as the radio signal.

  In the present invention, when the portable device transmits a signal requesting either the start of the engine of the vehicle or the driving battery system and the operation of the air conditioning to the in-vehicle device, to the vehicle parked at a remote place. Signal transmission and signal transmission to vehicles parked nearby are appropriately performed.

  (6) A portable device according to the present invention is a portable device that transmits / receives a signal to / from a vehicle-mounted device, a transmitter that transmits a spread spectrum modulated wireless signal to the vehicle-mounted device, and the wireless signal from the transmitter A receiving unit that receives a response signal from the in-vehicle device, a first transmission control unit that causes the transmission unit to perform spread modulation with a first spreading factor and transmit a radio signal, and a response signal corresponding to the radio signal Determining means for determining whether or not the signal can be received by the receiving unit within a predetermined waiting time; and if the determining means determines that the signal cannot be received, spread modulation with a second spreading factor higher than the first spreading factor And second transmission control means for retransmitting the radio signal.

  In the present application, similarly to the above-described aspect (1), the spreading factor is increased when the in-vehicle device cannot receive a signal and cannot receive a response signal by communication using a relatively low spreading factor. The spreading factor used in communication between the portable device and the in-vehicle device is optimized as necessary.

  (7) A communication method according to the present invention is a wireless signal communication method in a vehicle-mounted communication system including a portable device and a vehicle-mounted device each including a transmitter and a receiver that transmit and receive a spread spectrum modulated wireless signal. The transmission unit has caused the transmission unit to perform modulation modulation with a first spreading factor to transmit a wireless signal, and has the reception unit received the response signal from the in-vehicle device for the transmitted wireless signal within a predetermined waiting time? If it is determined that the signal cannot be received, the radio signal is retransmitted from the transmitter by performing spread modulation with a second spreading factor larger than the first spreading factor.

  In the present application, similarly to the above-described aspect (1), when the signal cannot be received by the vehicle-mounted device through communication using a relatively low spreading factor, the spreading factor is increased. The spreading factor used in communication between the portable device and the in-vehicle device is optimized as necessary.

[Details of the embodiment of the present invention]
A specific example of the in-vehicle communication system according to the embodiment of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to the claim are included.

(Embodiment 1)
FIG. 1 is an explanatory diagram showing an outline of the in-vehicle communication system according to the first embodiment. The in-vehicle communication system includes a portable device 1 possessed by a user and an in-vehicle device 2 in the vehicle V.

  The portable device 1 transmits and receives a signal for instructing the start of the engine of the vehicle V or the driving battery system or the operation of the air conditioning by wireless communication, and also wirelessly transmits a signal for unlocking / locking the door lock of the door. This is a so-called remote engine starter having a function of transmitting and receiving through communication.

  The in-vehicle device 2 is one of a plurality of ECUs (Electronic Controller Units) mounted on the vehicle, and controls the door lock / unlock, air conditioning, and interior / external lighting devices, etc. This is a so-called BCM (Body Control Module) that performs integrated control.

  The function of remote start from the portable device 1 in the in-vehicle communication system configured as described above is often used to make the passenger compartment comfortable before the user runs the vehicle V. When the vehicle V is parked in or near the driver's home, the distance between the portable device 1 and the vehicle V is, for example, within 50 meters, and the vehicle V is a large parking lot. When the vehicle is parked, the distance between the portable device 1 and the vehicle V may be longer than 50 meters. In such a case, when the remote start function is used, the portable device 1 and the in-vehicle device 2 according to the first embodiment are relatively relatively early in transmitting and receiving signals using the spread spectrum method. Communication is attempted with a small spreading factor, i.e. a relatively small range. If the signal from one side has not reached and communication is impossible, the spreading factor is increased, that is, the range of the signal is expanded and communication is attempted again.

  The detailed internal configuration of each device for changing the spreading factor as described above will be described. FIG. 2 is a block diagram showing a configuration of the in-vehicle communication system in the first embodiment. The portable device 1 includes a control unit 10, a transmission unit 11, and a reception unit 12.

  The control unit 10 is a microcontroller that uses, for example, one or a plurality of CPUs (Central Processing Units) or a multi-core CPU, and has a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, a timer, and the like. The CPU of the control unit 10 is connected to the transmission unit 11, the reception unit 12, the output unit 13, and the operation unit 14 via an input / output interface. The control unit 10 controls the operation of each component unit by executing a control program stored in the ROM.

  The transmitter 11 is a module including a transmission antenna that transmits a radio signal, a spreader that performs spread spectrum modulation, and a modulator. The transmission unit 11 performs carrier modulation on the signal input from the control unit 10 using an RF (Radio Frequency) signal, and performs spread spectrum modulation on the signal after carrier modulation using a spread spectrum method using a spreading factor. The transmission unit 11 extracts only a predetermined frequency band from the signal after spread modulation, and then amplifies the signal with a predetermined amplification factor and outputs the amplified signal to the transmission antenna. As a result, a signal spread in the RF band by the spread spectrum method is transmitted from the transmission antenna of the transmission unit 11. However, the frequency band here is not limited to this frequency band as long as it corresponds to the receiving antenna on the in-vehicle device 2 side.

  The receiving unit 12 is a module including a receiving antenna that receives a radio signal, a despreading unit that performs spectrum despreading modulation, and a demodulator. For example, a triaxial antenna is used as the receiving antenna. The receiving unit 12 extracts only components in a predetermined frequency band of the signal received by the receiving antenna, amplifies the extracted signal, and performs despread demodulation based on the spread spectrum method using the spreading factor specified based on the reception level. And demodulating using the carrier signal by the demodulator. The RF band is used as the frequency band of the carrier wave of the radio signal received by the receiving antenna of the receiving unit 12. However, the frequency band here is not limited to this frequency band as long as it corresponds to the transmitting antenna on the in-vehicle device 2 side.

  The output unit 13 outputs a buzzer sound, light using an LED (Light Emitting Diode) exposed on the surface of the portable device 1, or vibration. The output may be a combination of two or all of sound, light and vibration. The output unit 13 inputs an instruction signal from the control unit 10 and outputs sound, vibration, or light.

  The operation unit 14 is one or a plurality of buttons provided on the surface of the portable device 1. When the button is pressed, the operation unit 14 notifies the control unit 10. The buttons include a remote start button for instructing the start of the engine or the battery system for driving and the operation of air conditioning, respectively, and a door lock button for instructing locking / unlocking of the door lock.

  The in-vehicle device 2 includes a control unit 20, a reception unit 21, and a transmission unit 22.

  The control unit 20 is a microcontroller using, for example, one or a plurality of CPUs or a multi-core CPU and having a ROM, a RAM, an input / output interface, a timer, and the like. The control unit 20 is connected to an actuator 24 group such as an air conditioning system and a door lock, and controls the operation of the actuator 24 group based on a control program stored in advance in a ROM. Further, the control unit 20 instructs the engine control of the vehicle V or the drive battery control system via the in-vehicle communication unit (both not shown).

  The reception unit 21 uses a module including a reception antenna, a despreading unit, and a demodulator corresponding to the transmission unit 11 of the portable device 1. The frequency band used by the receiving unit 21 is the LF band. Of course, the frequency band is not limited as long as it corresponds to the transmission unit 11 of the portable device 1.

  The transmission unit 22 uses a module including a transmission antenna, a spreading unit, and a modulator corresponding to the reception unit 12 of the portable device 1. The frequency band used by the transmission unit 22 is the RF band. Of course, the frequency band is not limited as long as it corresponds to the transmission unit 12 of the portable device 1.

  In the vehicle-mounted communication system configured as described above, a process for transmitting and receiving a signal related to a remote start request while changing the spreading factor from the portable device 1 side will be described with reference to a flowchart. FIG. 3 is a flowchart illustrating an example of a processing procedure performed between the portable device 1 and the in-vehicle device 2 according to the first embodiment.

  In the portable device 1, when the operation unit 14 detects that the remote start button has been pressed by the user, the control unit 10 causes the transmission unit 11 to transmit a request signal at the first spreading factor (step S11). For example, the first spreading factor is set in the control program as a value that enables communication within a range of 50 meters from the portable device 1.

  Next, the control unit 10 determines whether or not a response signal (answerback) from the in-vehicle device 2 has been received within a predetermined first standby time corresponding to the first spreading factor (step S12).

  On the in-vehicle device 2 side, the control unit 20 determines whether or not the request signal from the portable device 1 has been received by the receiving unit 21 every time a certain time has elapsed (step S21). When it is determined that the signal cannot be received (S21: NO), the control unit 20 returns the process to step S21 and waits until it is determined that the signal can be received.

  If it is determined that the signal has been received in step S21 (S21: YES), authentication based on the request signal is executed (step S22), and operations such as the operation of the air conditioning system and the engine start are started according to the success or failure of the authentication ( Step S23). And the control part 20 acquires the spreading factor specified based on the receiving level in the center frequency band of the request signal received in the receiving part 21, and the receiving level in the frequency band apart from the fixed frequency from the receiving part 21 (step S24). ). The control unit 20 transmits a response signal from the transmission unit 22 based on the spreading factor acquired in step S24 (step S25), and ends the process.

  In transmission of the response signal from the in-vehicle device 2 in step S25, the spreading factor may be the same spreading factor as that obtained in step S24, but the spreading factor lowered by one or two steps is used. May be. This is because the signal can be transmitted with the electric power from the battery of the vehicle V on the vehicle-mounted device 2 side, and therefore the output power is higher than that of the small battery type portable device 1. Further, a predetermined larger diffusion rate may be used regardless of the diffusion rate acquired in step S24. Furthermore, spectrum response may not be used for transmission of the response signal from the in-vehicle device 2 side, and in this case, the process of step S24 is omitted.

  Note that, of course, if the authentication fails in step S22, the operation of the air conditioning system and the engine start in step S23 are impossible, and the processing is omitted. At this time, as the response signal, a signal indicating authentication failure may be transmitted from the in-vehicle device 2 side.

  In portable device 1, when it is determined in step S <b> 12 that the response signal has been received within the first waiting time (S <b> 12: YES), control unit 10 uses output unit 13 to indicate that an answerback has been received. Then, light or vibration is output (step S13), and the process is terminated.

  In step S12, when it is determined that the response from the request signal cannot be received within the first waiting time on the portable device 1 side (S12: NO), the control unit 10 determines from the transmission unit 11 that the response is greater than the first spreading factor. A request signal is transmitted at a high second spreading factor (step S14). The second spreading factor is set in the control program as a value that enables communication within a range of 300 meters, for example.

  The control unit 10 determines whether or not the response signal from the in-vehicle device 2 has been received within the second standby time corresponding to the second spreading factor (step S15). The second waiting time is longer than the first waiting time because it corresponds to a second spreading factor higher than the first spreading factor. When it is determined that the response signal has been received (S15: YES), the control unit 10 outputs a sound, light, or vibration indicating that the answerback has been received by the output unit 13 (step S16), and ends the process. To do.

  If it is determined in step S15 that the signal cannot be received within the second waiting time (S15: NO), the control unit 10 ends the process as it is because communication with the in-vehicle device 2 is impossible. At this time, the control unit 10 may output an error at the output unit 13.

  For example, when the vehicle V is parked in a parking lot near the house, the portable device 1 can communicate with the in-vehicle device 2 using the first spreading factor that is in the range of 50 meters. Thus, when the vehicle V is parked in a large parking lot, communication is possible when a large second spreading factor is used. As a comparison, in the configuration in which the diffusion rate is fixed and the range is widened as much as possible and the second diffusion rate is used, the vehicle V that should be parked nearby to use the remote start function near the home It seems that the answerback from is slow. On the other hand, in the configuration of the first embodiment described above, the first spreading factor is used when the vehicle V is nearby, and the second spreading factor is used when communication is impossible using the first spreading factor. The remote start function can be used with an appropriate spreading factor. Thereby, the standby time of an answer back can be shortened as much as possible, and comfort can be improved. Furthermore, the power consumption of the portable device 1 can be reduced by shortening the standby time initially and making it appropriate only when communication is impossible.

  In the flowchart of FIG. 3 described above, a configuration is used in which two diffusion rates, the first diffusion rate and the second diffusion rate, are used. However, the spreading factor may be increased from the minimum in three or more stages. FIG. 4 is a flowchart illustrating another example of the processing procedure performed by the portable device 1 according to the first embodiment. The processing procedure shown in the flowchart of FIG. 4 is a procedure only on the portable device 1 side and can be substituted for the processing (S11 to S16) on the portable device 1 side of the flowchart of FIG.

  When the operation unit 14 detects that the remote start button has been pressed by the user, the control unit 10 first selects a minimum spreading factor (step S101), and transmits a request signal at the selected spreading factor (step S101). S102). The minimum spreading factor is set in the control program as a value that enables communication within a range of 30 meters from the portable device 1, for example.

  Next, the control unit 10 determines whether or not a response signal (answerback) from the in-vehicle device 2 has been received within the standby time corresponding to the selected spreading factor (step S103). The waiting time is set in the control program so as to correspond to each of a plurality of diffusion rates.

  If it is determined in step S103 that reception has been completed within the corresponding waiting time (S103: YES), the control unit 10 outputs a sound, light, or vibration indicating that the answerback has been received by the output unit 13 (step S103). S104), the process is terminated.

  If it is determined in step S103 that the response signal cannot be received within the corresponding waiting time (S103: NO), the control unit 10 determines whether the spreading factor used in step S102 is the maximum spreading factor set. It is determined whether or not (step S105). When it is determined that it is not the maximum spreading factor (S105: NO), the control unit 10 increases the spreading factor (step S106), returns the process to step S102, and transmits the request signal at the increased spreading factor ( S102). The increase value of the spreading factor is, for example, a value that divides the minimum spreading factor and the maximum spreading factor equally or unevenly when the maximum spreading factor is set as a value that enables communication within a range of 300 meters. It is good to design appropriately.

  If it is determined in step S105 that the diffusion rate is the maximum (S105: YES), the control unit 10 ends the process as it is because communication with the in-vehicle device 2 is impossible. At this time, the control unit 10 may output an error at the output unit 13.

  With the processing shown in the flowchart of FIG. 4, it is possible to use a diffusion rate as small as possible within the range reaching the vehicle V. As a result, the remote start function can be used with an appropriate spreading factor according to the distance between the portable device 1 and the vehicle V (on-vehicle device 2). Thereby, the standby time of an answer back can be shortened as much as possible, and comfort can be improved. Furthermore, the power consumption of the portable device 1 can be reduced by shortening the standby time initially and making it appropriate only when communication is impossible.

  In the first embodiment, the in-vehicle device 2 has a configuration in which the spreading factor used for the spread modulation of the received signal can be specified from the reception level. However, the present invention is not limited to this. Information on the spreading factor used is added to the request signal transmitted from the portable device 1 in step S11 (step S102), and the spreading factor information is received from the signal received by the control unit 20 of the in-vehicle device 2. May be extracted.

(Embodiment 2)
FIG. 5 is a block diagram showing a configuration of the in-vehicle communication system in the second embodiment. The configuration of the in-vehicle communication system according to the second embodiment is the same as that of the first embodiment except that the portable device 1 includes a storage unit 15 that stores learning data 151 and performs processing according to the learning data 151. Therefore, in the in-vehicle communication system according to the second embodiment, the same reference numerals are used for the same components as in the first embodiment, and detailed description thereof is omitted.

  The portable device 1 in the second embodiment includes the storage unit 15 as described above. The storage unit 15 is a nonvolatile memory such as a flash memory. The storage unit 15 stores learning data 151 of information indicating a spreading factor and a situation (time and position) when communication is established with the in-vehicle device 2. In addition, the storage unit 15 stores a parking position. The parking position is longitude and latitude information that the control unit 20 acquires from, for example, the navigation system when the door locking button is pressed on the portable device 1 and a signal instructing locking is received by the in-vehicle device 2. It is added and transmitted from the in-vehicle device 2 to the portable device 1. The control unit 10 refers to the information stored in the storage unit 15 and selects and uses the diffusion rate to be used first. Hereinafter, the process of selecting a spreading factor using the learning data 151 of the storage unit 15 will be described with reference to a flowchart.

  FIG. 6 is a flowchart illustrating an example of a processing procedure performed by the portable device 1 according to the second embodiment. The control unit 10 specifies the time using the built-in timer (step S301). At this time, the control unit 10 may specify a time zone distinguished by morning, noon, evening, night, and midnight. The control unit 10 reads out the parking position stored in response to pressing of the door locking button from the storage unit 15 (step S302), and further refers to the learning data 151 from the storage unit 15 (step S303).

  The control unit 10 determines whether there is a spreading factor corresponding to both the time specified in step S301 and the parking position read in step S302 in the learning data 151 referred to in step S303 (step S304). ). It may be determined whether there is a spreading factor corresponding to only one of time or position.

  If it is determined in step S304 (S304: YES), the control unit 10 selects a corresponding spreading factor (step S305), and causes the transmission unit 11 to transmit a request signal with the selected spreading factor (step S305). S306).

  If it is determined in step S304 that it does not exist (S304: NO), the control unit 10 selects a minimum spreading factor (step S307), and causes the transmission unit 11 to transmit a request signal at the selected spreading factor (S306). ).

  Next, the control unit 10 determines whether or not a response signal (answerback) from the in-vehicle device 2 has been received within the standby time corresponding to the selected spreading factor (step S308). The waiting time is set in the control program so as to correspond to each of a plurality of diffusion rates.

  When it is determined in step S308 that the response signal has been received within the corresponding standby time (S308: YES), the control unit 10 outputs a sound, light, or vibration indicating that the answerback has been received by the output unit 13. (Step S309).

  Next, the control unit 10 stores the time information indicating the current time in association with the spreading factor used in step S306 in the learning data 151 (step S310). Further, the control unit 10 stores the vehicle position information indicating the current position added to the response signal in association with the spreading factor used in step S306 in the learning data 151 (step S311), and ends the process.

  If it is determined in step S308 that the response signal cannot be received within the corresponding waiting time (S308: NO), the control unit 10 determines whether the spreading factor used in step S306 is the maximum spreading factor set. It is determined whether or not (step S312). When it is determined that it is not the maximum spreading factor (S312: NO), the control unit 10 increases the spreading factor (step S313), returns the process to step S306, and transmits the request signal with the increased spreading factor (step S313). S306).

  If it is determined in step S312 that the maximum spreading factor is obtained (S312: YES), the control unit 10 ends the process as it is because communication with the in-vehicle device 2 is impossible. At this time, the control unit 10 may output an error at the output unit 13.

  FIG. 7 is an explanatory diagram illustrating an example of the content of learning data according to the second embodiment. For example, when the user presses the remote start button of the portable device 1 before entering the vehicle V parked in the parking lot in front of the house for work in the morning according to the processing procedure shown in the flowchart of FIG. When no information is included in 151, the minimum spreading factor is selected (S307), and transmission of a request signal is attempted. When the distance between the portable device 1 and the in-vehicle device 2 is very close, such as when the vehicle V is parked in a parking lot in front of the house, communication with the in-vehicle device 2 is established even with the minimum spreading factor. For this reason, the morning time zone, position information (longitude and latitude) around the home, and the minimum spreading factor are stored in association with each other in the learning data 151 in steps S310 and S311.

  After that, when the user parks the vehicle V in the parking lot around the office and presses the remote start button of the portable device 1 when returning home, the minimum diffusion rate is obtained when no information is included in the learning data 151. When selected (S307), transmission of a request signal is attempted. When the parking lot around the office is a little away from the place where the remote start button is pressed, when the distance between the portable device 1 and the in-vehicle device 2 is about 100 meters away, the diffusion rate increased to some extent from the minimum diffusion rate Thus, communication is established between the portable device 1 and the in-vehicle device 2. Through the steps S310 and S311, the evening time zone, the location information (latitude and longitude) around the workplace, and the increased use diffusion rate are stored in association with each other in the learning data 151.

  Thereafter, when the user presses the remote start button in the same manner when going to work in the morning, the position information around the home is stored as the parking position in the storage unit 15 of the portable device 1 during parking, and the morning time is stored in the learning data 151. There is a spreading factor corresponding to the belt and position information around the home. Therefore, the spreading factor (low) stored in the learning data 151 is used. Similarly, when the user presses the remote start button around the workplace when returning from the workplace, the location information of the parking lot around the workplace is stored as a parking position in the storage unit 15 of the portable device 1 at the time of parking. The learning data 151 includes a spreading factor corresponding to the evening time zone and the location information of the parking lot around the workplace. Therefore, the spreading factor (medium) stored in the learning data 151 is used as the initial value. When the user presses the remote start button from the store against the vehicle V parked in the large store parking lot on the road during the daytime on a holiday (for example, Saturday and Sunday), the learning data 151 includes: There is no spreading factor corresponding to the location information of the large store parking lot stored as the parking location. Therefore, in this case, the minimum spreading factor is used as the initial value. When communication is established with the increased spreading factor by repeating the processes of steps S306, S308, and S313, the location information on the weekends and around the large store and the used spreading factor (high) are newly learned data 151. Will be added.

  In this way, by using the diffusion rate as the initial value with reference to the learning data 151 corresponding to the diffusion rate used with the time (time information) and / or the position of the vehicle, the time and place An appropriate diffusion rate can be used. It is possible to realize long-distance communication with power saving using spread spectrum, and since the appropriate spreading factor is used, the waiting time can be optimized according to the spreading factor, eliminating the uncomfortable feeling of waiting time, Comfort can be improved. The power consumption can also be optimized by optimizing the standby time.

1 portable device 10 control unit (first transmission control means, second transmission control means, judgment means, second judgment means, time judgment means, position judgment means)
DESCRIPTION OF SYMBOLS 11 Transmission part 12 Reception part 13 Output part 14 Operation part 15 Storage part (Corresponding storage part, own vehicle position storage part)
151 Learning data (corresponding storage unit)
2 On-vehicle device 20 Control unit 21 Reception unit 22 Transmission unit

Claims (7)

In an in-vehicle communication system that performs wireless communication between a portable device and an in-vehicle device,
The portable device is
A transmitter that transmits a spread spectrum modulated radio signal to the in-vehicle device;
A receiving unit that receives a response signal from the in-vehicle device with respect to the wireless signal from the transmitting unit;
First transmission control means for causing the transmission unit to perform spread modulation with a first spreading factor and transmit a radio signal;
Determining means for determining whether or not a response signal corresponding to the wireless signal has been received by the receiving unit within a predetermined standby time;
In-vehicle communication, comprising: second transmission control means for retransmitting a radio signal by performing spread modulation at a second spreading factor higher than the first spreading factor when the judging means judges that reception is impossible system. A second determination means for determining whether or not a response signal corresponding to the radio signal retransmitted from the transmission section by the second transmission control means can be received by the reception section within a second waiting time;
The in-vehicle communication system according to claim 1, wherein the second waiting time is longer than the predetermined waiting time. The portable device is
A storage unit that stores a correspondence of spreading information when the response signal is received by the reception unit, and time information indicating a time when the response signal is received;
Time determination means for determining whether or not the time indicated by the time information included in the correspondence stored in the storage unit matches the time at which the wireless signal is spread-modulated in the transmission unit;
The in-vehicle communication system according to claim 1 or 2, wherein when the time determination means determines that they match, a spreading factor corresponding to the time information is used as the first spreading factor. The in-vehicle device adds the vehicle position information to the response signal and transmits it,
Further comprising position transmitting means for transmitting the vehicle position information to the portable device triggered by door locking;
The portable device is
A correspondence storage unit for storing a spreading factor when the response signal is received by the reception unit, and a correspondence of the vehicle position information added to the response signal;
A host vehicle position storage unit that stores the host vehicle position information transmitted from the position transmission unit;
When the wireless signal is spread and modulated by the transmission unit, the vehicle position information stored in the vehicle position storage unit and the time indicated by the vehicle position information included in the correspondence stored in the correspondence storage unit And position determining means for determining whether or not match,
3. The in-vehicle communication system according to claim 1, wherein when it is determined that the one determination unit matches, a spreading factor corresponding to the vehicle position information is used as the first spreading factor. The vehicle-mounted communication system according to any one of claims 1 to 4, wherein the portable device transmits a signal requesting start of an engine or a driving battery system and an operation of air conditioning as the wireless signal. In portable devices that send and receive signals to and from in-vehicle devices,
A transmitter that transmits a spread spectrum modulated radio signal to the in-vehicle device;
A receiving unit that receives a response signal from the in-vehicle device with respect to the wireless signal from the transmitting unit;
First transmission control means for causing the transmission unit to perform spread modulation with a first spreading factor and transmit a radio signal;
Determining means for determining whether or not a response signal corresponding to the wireless signal has been received by the receiving unit within a predetermined standby time;
A portable device comprising: a second transmission control unit configured to perform spread modulation at a second spreading factor higher than the first spreading factor and retransmit a radio signal when the judging unit determines that the signal cannot be received; . In a wireless signal communication method in an in-vehicle communication system including a portable device and an in-vehicle device each having a transmitting unit and a receiving unit for transmitting and receiving a spread spectrum modulated radio signal,
The portable device is
Causing the transmitter to transmit a radio signal by performing spread modulation with a first spreading factor;
Determining whether or not a response signal from the in-vehicle device for the transmitted wireless signal has been received by the receiving unit within a predetermined standby time;
When it is determined that reception is not possible, a radio signal is retransmitted from the transmitter by performing spread modulation with a second spreading factor larger than the first spreading factor.

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