JP2010068150A - Communication system, transmitter, receiver and control method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress power consumption during a reception operation in a data communication system using a plurality of channels of different frequencies. <P>SOLUTION: The communication system includes: the transmitter 21 for transmitting data using the plurality of channels of the different frequencies; and the receiver comprising a reception part 12 for receiving the data, and a control part 14 for causing the reception part 12 to wait for the data in part of a period using some of the plurality of channels when the reception part 12 does not receive the data for the first prescribed time or longer and executing reception control processing for causing the reception part 12 to wait for the data using the plurality of channels of the different frequencies successively if the reception part 12 receives the data thereafter and power control processing for interrupting power supply to the reception part 12 in the period other than part of the period when the reception part 12 waits for the data using some channels. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a communication system, a transmission apparatus, a reception apparatus, and control methods thereof, and more particularly, to a communication system, a transmission apparatus, a reception apparatus, and control methods thereof that perform data communication using a plurality of channels having different frequencies.

  For example, a communication system that performs data communication using a plurality of channels having different frequencies, such as communication using frequency hopping, is used. For example, in the United States, a transmission output up to 250 mW is possible in an ISM (Industrial Scientific Medical) frequency band by the FCC (Federal Communication Commission) without a license. However, the same frequency cannot be used for a certain period. Therefore, a frequency hopping technique is used.

  As a communication system used in the ISM frequency band, there is a system for controlling a vehicle from a remote communication device. For example, in a remote engine starter system, an ECU (Electric Control Unit) starts an engine of a vehicle based on an engine start signal from a remote communication device. In the remote entry system, an ECU (Electric Control Unit) unlocks or locks the vehicle door based on the unlocking / locking signal from the remote communication device.

It is known that when a frequency hopping technique is used in a remote keyless entry system, power consumption is large during a receiving operation and a burden is imposed on a vehicle battery (Patent Document 1). In order to reduce the power consumption of the communication system, it is known to adjust the timing of shifting to the power saving mode and the period of the intermittent signal in the power saving mode according to the communication format of packet communication (Patent Document 2).

JP 2002-54331 A JP 2003-179539 A

  Although it is known that the power consumption increases during the reception operation using the frequency hopping technique as in Patent Document 1, in the data communication system using a plurality of channels having different frequencies, the power consumption during the reception operation is reduced. No specific method of suppression has been proposed.

  The present invention has been made in view of the above problems, and an object of the present invention is to suppress power consumption during a reception operation in a data communication system using a plurality of channels having different frequencies.

  The present invention provides a transmitting apparatus that transmits data using a plurality of channels having different frequencies, a receiving unit that receives the data, and the receiving unit when the receiving unit does not receive the data for the first predetermined time or more. When a part of a plurality of channels is used to wait for the data in a part of the period, and then the receiving unit receives the data, the receiving unit sequentially uses the plurality of channels to receive the data. And a power control process for shutting off the power supply to the receiver in a period other than the part of the period when the receiver uses the part of the channel and waits for the data. And a receiving device including a control unit. According to the present invention, the receiving device does not have to wait for data by sequentially using a plurality of channels. Therefore, power consumption of the receiving device can be reduced.

  In the above configuration, the transmitting device transmits a data to the receiving device using any one of the plurality of channels, and when the transmitting unit does not transmit the data for a second predetermined time or more, In the case where the transmission unit transmits data using the partial channel, and then transmits another data within a third predetermined time, the transmission unit is configured to transmit another partial channel among the plurality of channels. And a control unit that transmits the different data. According to this configuration, the transmission device can transmit data using the channel on which the reception device is waiting.

  The said structure WHEREIN: The said control part of the said receiving apparatus can be set as the structure which notifies to the said transmitting apparatus, when there exists an error in the said data which the said receiving part received in the said reception control process.

  In the above configuration, when there is an error in the data received by the reception unit in the reception control process, the control unit of the reception device notifies the transmission device, and the control unit of the transmission device When the information indicating that there is an error in the data received by the receiving device is received from the receiving device, the number of the other partial channels may be increased. According to this configuration, when the reception state of the reception device is poor, the number of channels for transmitting data to the transmission device can be increased, and communication quality can be improved.

  In the above configuration, the data includes a data body and a preamble transmitted before the data body, the receiving unit waits for the preamble, and the control unit is configured to receive the preamble in the reception control process. When a preamble is received, the reception unit can be configured to receive the data body using a channel that has received the preamble. According to this configuration, the receiving unit can reliably receive the data body.

  In the above configuration, a waiting time of one channel when the receiving unit waits for the data using the partial channel, and one channel when the receiving unit sequentially uses the plurality of channels to receive the data The standby time can be the same.

  The said structure WHEREIN: The said data can be set as the structure which is data for controlling a vehicle.

  The present invention relates to a receiving unit that receives data transmitted by a transmitting device using a plurality of channels having different frequencies, and when the receiving unit does not receive the data for the first predetermined time or more, the receiving unit receives a plurality of channels. A reception control process in which a part of the channels is used to wait for the data in a part of a period, and then the receiver receives the data when the receiver receives the data. And a control unit that executes a power control process for cutting off power supply to the receiving unit in a period other than the partial period when the receiving unit waits for the data using the partial channel. And a receiving apparatus characterized by comprising: According to the present invention, the receiving unit does not have to wait for data by sequentially using a plurality of channels. Therefore, power consumption of the receiving device can be reduced.

  In the above configuration, the control unit may notify the transmission device when there is an error in the data received by the reception unit in the reception control process.

  The present invention provides a transmitting unit that transmits the data to a receiving apparatus using any one of a plurality of channels having different frequencies, and a plurality of transmitting units when the transmitting unit does not transmit the data for a second predetermined time or more. Data is transmitted using a predetermined part of the channels, and after the transmission unit transmits the data using the predetermined part of the channel, another data is transmitted within a second predetermined time. In this case, the transmission apparatus includes a control unit that causes the transmission unit to transmit the other data using another part of the plurality of channels. According to the present invention, since the transmission unit transmits data using a part of predetermined channels among a plurality of channels, the receiving apparatus does not have to wait for data by sequentially using the plurality of channels. Therefore, power consumption of the receiving device can be reduced. Further, data can be transmitted using a channel different from the channel used for the previous transmission.

  In the above configuration, when the control unit receives information indicating that there is an error in the data received by the receiving device from the receiving device, the control unit increases the number of the other partial channels. it can. According to this configuration, when the reception state of the reception device is poor, the number of channels for transmitting data to the transmission device can be increased, and communication quality can be improved.

  The present invention is a control method of a communication system comprising: a transmission device that transmits data using a plurality of channels having different frequencies; and a reception device that includes a reception unit that receives the data, wherein the reception unit 1 If the data is not received for a predetermined time or longer, the receiving unit uses a part of a plurality of channels to wait for the data in a part of the period, and then the receiving unit receives the data The receiving unit sequentially using the plurality of channels having different frequencies to receive the data, and when the receiving unit waits for the data using the partial channel, in a period other than the partial period And a step of cutting off power supply to the receiving unit.

  The said structure WHEREIN: The said data can be set as the structure which is data for controlling a vehicle.

  The present invention is a control method of a receiving device including a receiving unit that receives data transmitted by a transmitting device using a plurality of channels having different frequencies, and the receiving unit does not receive the data for the first predetermined time or more. , Causing the receiving unit to wait for the data in a part of a period using a part of the plurality of channels, and then when the receiving unit receives the data, the receiving unit receives the plurality of channels. Sequentially using the data and receiving the data when the receiving unit waits for the data using the part of the channel and cutting off the power supply to the receiving part in a period other than the part of the period; A control method for a receiving apparatus.

  The present invention is a control method of a transmission device including a transmission unit that transmits the data to the reception device using any one of a plurality of channels having different frequencies, and the transmission unit transmits the data for a second predetermined time or more. When not transmitting, the step of causing the transmitter to transmit data using a predetermined part of a plurality of channels, and after the transmitter transmits the data on the predetermined part of the channel, A step of transmitting the other data using another part of the plurality of channels when the other data is transmitted within the second predetermined time. This is a control method of the transmitting apparatus.

  According to the present invention, the receiving device does not have to wait for data by sequentially using a plurality of channels. Therefore, power consumption of the receiving device can be reduced.

  Embodiments will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating the in-vehicle device of the communication system according to the first embodiment. With reference to FIG. 1, the in-vehicle device 10 receives information for instructing engine start, door lock, door unlock, and the like from the portable device 20. A remote starter ECU (Electric Control Unit) 60 transmits / receives data TRXD transmitted / received to / from the mobile device 20 to / from the in-vehicle device 10. The body ECU 62 locks / unlocks the door based on information from the remote starter ECU 60. The EFI-ECU 64 starts the engine based on information from the body ECU 62.

  The interface (IF) circuit 58 inputs and outputs data TRXD transmitted and received from the remote starter ECU 60 to a CPU (Central Processing Unit) 42. The CPU 42 controls the transmission / reception data TDXD as described later, and transmits / receives it to / from the transmission / reception IC 38. The memory 46 stores various data from the CPU 42. The clock circuit 44 outputs a clock to the CPU 42. A reset WDT (Watch Dog Timer) 48 transmits a reset signal to the CPU 42 and receives a WDO (Watch Dog Output) signal from the CPU 42. The reset WDT 48 resets the CPU 42 based on the power supply and WDO. The power supply circuit 52 steps down the + B voltage of the battery and supplies it as Vcc54 to the power amplifier PA34 via the CPU 42, the transmission / reception IC 38, and the power supply control circuit 50. Further, a battery ground GND 56 is supplied to the CPU 42 and the transmission / reception IC 38.

  The transmission / reception IC 38 converts the transmission data received from the CPU 42 into a high-frequency signal, and then up-converts the transmission data into a high-frequency signal of 900 MHz, for example, and supplies it to the PA 34. Further, after down-converting the received signal received from the SAW (Surface Acoustic Wave) filter 36, it is demodulated and output to the CPU 42 as received data. The transmission / reception IC 38 receives from the CPU 42 an enable signal EN that activates the transmission / reception IC 38, a control signal CONT that controls the transmission / reception IC 38, and a clock CL. The crystal oscillator 40 generates an oscillation signal for up-converting or down-converting a transmission / reception signal. The PA 34 amplifies the transmission signal. An RF (Radio Frequency) switch 32 switches between a transmission signal transmitted from the antenna 30 and a reception signal received based on the RFSW signal of the CPU 42. The SAW filter 36 filters the received signal. The power supply control circuit 50 cuts off the power supply of the PA 34 based on the RFSW signal.

  FIG. 2 is a block diagram illustrating the portable device. Referring to FIG. 2, the microcomputer 82 controls transmission / reception data TDXD as described later, and transmits / receives data to / from the transmission / reception IC 78. The lock SW, unlock SW, start SW, function SW and panic SW are control switches 98. When the user locks or unlocks the vehicle door, the user turns on the lock SW and the unlock SW, respectively. When starting the engine of the vehicle, the start SW is turned on. The user can perform more complicated operations by using the function SW. Further, the user can turn on the panic switch for threats in an emergency. A signal from the control switch 98 is input to the microcomputer 82. The microcomputer 82 can notify the user that the door has been locked, unlocked, and the engine has been started by turning on an LED (Light Emitting Device) 88. Further, the user can be notified by turning on the LED 88 that the user is out of the transmission / reception range or that the trunk is open. The battery 92 supplies the ground GND 96 to the microcomputer 82 and the transmission / reception IC 78. The power supply circuit 90 converts the battery voltage into Vcc 94 and supplies it to the microcomputer 82 and the transmission / reception IC 78. The functions of the transmission / reception IC 78, the CLK 84, the memory 86, the XTAL 80, the PA 74, the SAW filter 76, the RF switch 72, and the antenna 70 are the same as those of the parts of the in-vehicle device 10, and the description thereof is omitted.

  FIG. 3A is a functional block diagram of the receiving apparatus, and FIG. 3B is a functional block diagram of the transmitting apparatus. The receiving device 11 is the in-vehicle device 10 when receiving the RF signal from the portable device 20, and the transmitting device 21 is the portable device 20 when transmitting the RF signal to the in-vehicle device 10. When the in-vehicle device 10 transmits an RF signal, the in-vehicle device 10 can be the transmission device 21, and when the portable device 20 receives the RF signal, the portable device 20 can be the reception device 11.

  With reference to FIG. 3A, the transmission / reception IC 38 of the in-vehicle device 10 functions as the reception unit 12. The receiving unit 12 receives the RF signal (transmission data) transmitted from the transmission device 21. The CPU 42 functions as the control unit 14. The control unit 14 includes a reception control unit 15 that performs a reception control process and a power control unit 16 that performs a power control process. The power supply circuit 52 functions as the power supply unit 18. The power supply unit 18 supplies power to the receiving unit 12. The power control unit 16 controls the power supplied to the receiving unit 12. Referring to FIG. 3B, the transmission device 21 is a device that transmits data using a plurality of channels having different frequencies. The transmission / reception IC 78 of the portable device 20 functions as the transmission unit 22. The transmission unit 22 transmits data to the reception device 11 using any one of a plurality of channels. The microcomputer 82 functions as the control unit 24. The control unit 24 performs transmission control processing.

  Next, a comparative example using the frequency hopping technique will be described. In this example, the channels having different frequencies are 25 channels, and the frequency interval between adjacent reception channels is, for example, 350 kHz. In FCC, the frequency interval is set to 250 kHz or more, and the use frequency is set to 902 to 928 MHz. A transmission signal transmitted by the transmission unit 22 includes a preamble and a data body. The preamble is a signal for fixing the receiving unit 12 to a frequency for receiving the data body.

  FIG. 4 is a flowchart showing processing of the receiving device 11 according to the comparative example. Referring to FIG. 4, the power supply circuit 52 starts operating, and the reset of the CPU 42 is released (step S10). The reception control unit 15 starts the reception unit 12 to sweep the reception channel (step S12). The reception control unit 15 determines whether the reception unit 12 has received the preamble (step S14). In the case of No, the reception control unit 15 causes the reception unit 12 to continue sweeping the reception channel (step S16). The reception control unit 15 determines whether it is finished (step S18). In the case of Yes, it complete | finishes, and in No, it returns to step S14.

  In step S14, in the case of Yes, the reception control unit 15 causes the reception unit 12 to fix the reception channel (step S20). The reception control unit 15 causes the reception unit 12 to receive the data body (step S22). The control unit 14 transmits the received data to the remote starter ECU 60. The remote starter ECU 60 performs processing based on the received data (step S24). The process returns to step S16.

  FIG. 5 is a flowchart showing processing of the transmission device 21 according to the comparative example. Referring to FIG. 5, the power supply circuit 90 starts to operate and the microcomputer 82 operates (step S30). The control unit 24 detects that the control switch 98 is turned on (step S32). The transmission control unit 25 determines whether the transmission is the first transmission of the transmission unit 22 (step S34). In No, the transmission control part 25 adds 1 to the previous transmission channel, and is set as a transmission channel (step S36). The transmission control unit 25 causes the transmission unit 22 to transmit a transmission signal composed of a preamble and a data body (step S38). The transmission control unit 25 adds 1 to the transmission channel to make a transmission channel (step S40). The transmission control unit 25 causes the transmission unit 22 to transmit the same transmission signal as that in step S38 (step S42). The transmission control unit 25 determines whether or not to end (step S44). If it is Yse, the process ends. If it is No, the process returns to step S32.

  In step S34, in the case of Yes, the transmission control unit 25 causes the transmission unit 22 to set the transmission channel to CH1 (step S46). The transmission control unit 25 causes the transmission unit 22 to transmit a transmission signal (step S48). The transmission control unit 25 causes the transmission unit 22 to set the transmission channel to CH2 (step S50). The transmission control unit 25 causes the transmission unit 22 to transmit the same transmission signal as that in step S48 (step S52). In the above transmission control process, the transmission channel is stored in the memory 96 which is a nonvolatile memory, for example.

  FIG. 6A and FIG. 6B are time charts showing the operation during the reception control process. FIG. 6B is an enlarged view of FIG. The transmission / reception IC on / off indicates the power on / off of the reception unit 12 (transmission / reception IC 38) performed by the power control unit 16. The reception control indicates a standby process of the reception unit 12. With reference to FIG. 6A and FIG. 6B, the power supply of the receiving unit 12 is turned on in step S12 of FIG. Thereafter, the receiving unit 12 sweeps the reception channels CH1 to CH25. As described above, the sweep of the reception channel is to sequentially use a plurality of channels having different frequencies so as to hold the transmission data. Here, the time of the first reception channel CH1 is, for example, 10 ms in order to set the mode and wait for the reception channel. The standby time after the reception channel CH2 is, for example, 2.5 ms because it is only the standby time. Thus, in sweeping the reception channel, the reception unit 12 sweeps the reception channel and takes a signal from the transmission device 21. The reception channel may not be swept in order from channel CH1 to CH25. For example, a plurality of channels may be used sequentially in an arbitrary order.

  FIG. 7 is a time chart showing the operation during the transmission control process. On / off of the control switch indicates on / off of the control switch 98. The wake-up / sleep of the microcomputer indicates the wake-up / sleep of the microcomputer 82. The transmission / reception IC on / off indicates the power on / off of the transmission unit 22 (transmission / reception IC 78). The transmission control indicates a transmission control process of the transmission unit 22. The transmission data indicates transmission data (transmission signal) transmitted by the transmission unit 22. Referring to FIG. 7, when the control switch 98 is pressed in step S32 of FIG. 5, the microcomputer 82 wakes up and the transmission / reception IC 78 which is the transmission unit 22 is turned on. In step S36 or S46 of FIG. 5, the transmission control unit 25 performs mode setting, and transmits transmission data on the transmission channel m in step S38 or S48. The transmission data is an 80 ms preamble and a data body. In step S40 or S50 of FIG. 5, the transmission control unit 25 performs mode setting and transmits the same transmission data through the transmission channel n. The transmission data includes a data body and a preamble transmitted before the data body. The length of the preamble of transmission data is 80 ms.

  FIG. 8A to FIG. 8D are time charts showing operations when transmission data is received during the reception control processing of the receiving apparatus. When the receiving unit 12 does not receive transmission data with reference to FIG. 8A, the receiving unit 12 sweeps the reception channels CH1 to CH25. Referring to FIG. 8B, the transmission device 21 transmits the transmission data of the transmission channel CH23. Referring to FIG. 8C, as in step S20 of FIG. 4, the reception control unit 15 fixes the reception channel in the reception unit 12 to the same channel CH23 as the channel of the transmission data. Referring to FIG. 8D, the receiving unit 12 receives a preamble and a data body as received data.

  According to the FCC, communication with a transmission power of 250 mW is possible. However, if communication is performed on a certain channel, transmission on the same channel cannot be performed thereafter for a predetermined period (10 seconds). For example, when frequency hopping is performed using 25 channels, communication of 400 ms or more cannot be performed using one channel. In the communication system of the comparative example, as in steps S36, S40, S46, and S50 of FIG. 5, the same channel is changed within a predetermined period (10 seconds) by changing the transmission channel each time the control switch 98 is operated. Can be prevented.

  As in steps S12 and S16 in FIG. 4, the reception control unit 15 causes the reception unit 12 to sweep the reception channel and wait for it. As in step S20, the reception control unit 15 causes the reception unit 12 to fix the reception channel when the reception unit 12 receives the preamble. Thereby, even if the transmission part 22 changes and transmits a transmission channel, the receiving part 12 can receive transmission data.

  Here, the transmission data preamble period is longer than the time of one channel (2.5 ms in FIG. 6B) × the number of channels (25 channels) when the reception unit 12 sweeps the reception channel (see FIG. 6). 7 is set to 80 ms). As a result, the receiving unit 12 can reliably receive the preamble of the transmission data.

  Further, as in steps S42 and S52 of FIG. 5, the transmission control unit 25 causes the transmission unit 22 to transmit the same transmission data through different channels. As a result, even when the reception device 11 cannot receive the transmission data transmitted on one channel due to the influence of the interference wave, the reception device 11 can receive the transmission data transmitted on a different channel. Become.

  However, in the communication system according to the comparative example, as shown in FIG. 6B, the receiving unit 12 continuously sweeps the receiving channel, so that the receiving unit 12 is continuously powered on. Therefore, in a device with a limited power supply capacity such as the in-vehicle device 10 and the portable device 20, reduction of the power consumption of the receiving unit 12 is required.

  The communication system according to the first embodiment that can reduce the power consumption of the receiving unit 12 will be described below. FIG. 9 is a flowchart illustrating the operation of the receiving device 11 according to the first embodiment. Referring to FIG. 9, if No in step S14 of FIG. 4 of the comparative example, it is determined whether the first predetermined time has elapsed (step S60). For example, the first predetermined time may be 10 seconds. In No, it progresses to Step S16. In the case of Yes, the reception control unit 15 causes the reception unit 12 to set the reception channel to CH1 (step S62). The reception control unit 15 determines whether the reception unit 12 has received a preamble on the reception channel CH1 (step S64). In No, the reception control part 15 makes the receiving part 12 set a receiving channel to CH8 (step S66). The reception control unit 15 determines whether the reception unit 12 has received the preamble on the reception channel CH8 (step S68). In No, the power supply control part 16 interrupts | blocks the power supply of the receiving part 12 during the period when the receiving part 12 respond | corresponds to receiving channels other than receiving channel CH1 or CH8 (step S70). The process returns to step S62. If Yes in step S64 or S68, the process proceeds to step S20. The other steps are the same as those of the comparative example shown in FIG.

  FIG. 10 is a flowchart illustrating the operation of the transmission device 21 according to the first embodiment. With reference to FIG. 10, in the case of No in step S <b> 34 of FIG. 5 of the comparative example, the transmission control unit 25 determines whether a second predetermined time has elapsed since the previous transmission (step S <b> 76). In No, it progresses to Step S36. In the case of Yes, it progresses to step S46. After step S48, the transmission control unit 25 causes the transmission unit 22 to set the transmission channel to CH8 (step S72). The transmission control unit 25 causes the transmission unit 22 to transmit the same transmission data as in step S48 using the transmission channel CH8 (step S74). Thereafter, the process proceeds to step S44. Other steps are the same as those of the comparative example shown in FIG.

  FIG. 11A and FIG. 11B are time charts showing the operation during the reception control process. FIG.11 (b) is an enlarged view of Fig.11 (a). Referring to FIGS. 11 (a) and 11 (b), after the first predetermined time has elapsed in step S60 of FIG. 9, if the receiver 12 does not receive a preamble in step S64 or S68, the receiver 12 Transmission data is awaited only on channels CH1 and CH8. In FIG. 8A, during the period in which the receiving unit 12 is waiting for transmission data in a reception channel other than the reception channel CH1 or CH8, transmission data is not waited in FIG. 11B. Therefore, as in step S70 of FIG. 9, the power supply control unit 16 sets the reception unit 12 in a period in which a reception channel other than the reception channel CH1 or CH8 is to be received in the reception channel sweep of FIG. Turn off the power. Moreover, the control part 14 makes CPU42 a sleep state. As a result, during the period Toff in FIG. 11A, the power of the receiving unit 12 is turned off, and the CPU 38 goes to sleep.

  FIG. 12 is a time chart showing the operation during the transmission control process. Referring to FIG. 12, when the first predetermined time has elapsed since the previous transmission in step S76 in FIG. 10 when the control switch is turned on, the transmission control unit is set as in steps S46, S48, S72 and S74 in FIG. 25 causes the transmission unit 22 to transmit transmission data using the transmission channels CH1 and CH8.

  FIG. 13A to FIG. 13C are time charts showing operations when transmission data is received during the reception control processing of the receiving apparatus. Referring to FIG. 13A, when receiving unit 12 is waiting for reception on reception channels CH1 and CH8, transmission device 21 transmits transmission data on transmission channel CH8. As in step S20 of FIG. 9, the reception control unit 15 causes the reception unit 12 to fix the reception channel to CH8. The reception unit 12 receives the preamble and the data body as reception data as reception data, as in step S22 of FIG. Referring to FIG. 13B, thereafter, as in step S16 in FIG. 9, the reception control unit 15 causes the reception unit 12 to sweep the reception channel from CH1 to CH25. Referring to FIG. 13C, the reception control unit 15 causes the reception unit 12 to sweep the reception channel for a first predetermined time (10 seconds). If the preamble is not received again within the first predetermined time as in step S60 of FIG. 9, the reception control unit 15 causes the reception unit 12 to fix the reception channel to CH1 and CH8.

  According to the first embodiment, when the reception unit 12 does not receive transmission data for the first predetermined time or longer, the reception control unit 15 allows the reception unit 12 to set a plurality of channels CH1 to CH25 as in steps S62 to S68 in FIG. Of these, some of the channels CH1 and CH8 are used to wait for transmission data in some periods. Thereafter, when the receiving unit 12 receives the transmission data, the receiving control unit 15 causes the receiving unit 12 to sweep the receiving channel as in step S16 of FIG. When the receiving unit 12 waits for transmission data using some of the channels CH1 and CH8, as in step S70 of FIG. 9, the power supply control unit 16 uses some of the channels CH1 to CH25 and some of the channels CH1 and CH8. The power supply to the receiving unit 12 is cut off when it is necessary to wait for a channel other than (a period other than a part of the period). Thereby, the receiving part 12 does not need to always sweep the receiving channel. Therefore, the power consumption of the receiving device 11 can be reduced. Some of the channels may be one channel or a plurality of two or more channels.

  Further, according to the first embodiment, when the transmission unit 22 does not transmit the transmission data for the second predetermined time or longer, the transmission control unit 25 transmits the transmission data to the transmission unit 22 as in steps S46, S48, S72, and S74 in FIG. Transmission data is transmitted using some predetermined channels CH1 and CH8. As described above, when the transmission apparatus 21 does not transmit transmission data for the second predetermined period or longer, the transmission apparatus 21 can use the same transmission channel as the reception channel on which the reception apparatus 11 waits for transmission data within the first predetermined period. That is, the reception channel and the transmission channel are determined in advance to be the same. Therefore, the transmission device 21 can transmit transmission data using the channel on which the reception device 11 is waiting.

  In addition, when another transmission data is transmitted within a second predetermined period (for example, 10 seconds defined by the FCC) after transmitting the previous transmission data, the transmission channel used for the previous transmission cannot be used. Therefore, in the first embodiment, after transmitting the previous transmission data, the transmission control unit 25 transmits another data to the transmission unit 22 within a second predetermined time (may be a third predetermined time different from the second predetermined time). When doing so, as in steps S36 to S42 of FIG. 10, the transmission unit 22 is caused to transmit different data using another part of the plurality of channels CH1 to CH25. Thereby, transmission data can be transmitted using a transmission channel different from the transmission channel used for the previous transmission. The first predetermined time to the third predetermined time are preferably the same.

  Further, the receiving unit 12 waits for a preamble, and when the receiving unit 12 receives the preamble, the reception control unit 15 can cause the receiving unit 12 to receive the data body using the channel that has received the preamble. Thereby, the receiving part 12 can receive the data main body reliably.

  In steps S62 to S70 of FIG. 9, when receiving channels CH1 and CH8 are set, the period for carrying transmission data on reception channels CH1 and CH8 may be shorter than the preamble period of the transmission data. Thereby, the receiving part 12 can receive transmission data more reliably. For ease of control, it is preferable that the length of the preamble of the transmission data does not change between steps S38, S42 and S48, S74 in FIG. Therefore, the period for receiving transmission data in the reception channels CH1 and CH8 may be the same as the period for sweeping the reception channel.

  Further, when setting the reception channels CH1 and CH8 in steps S62 to S70 of FIG. 9, the standby time of one channel CH1 or CH8 is the same as the standby time of each channel CH1 to CH25 in step S16. Is preferred. If the lengths of the preambles of the transmission data are the same, it is not necessary to change the standby time of one channel, and control is facilitated by making the standby time per channel the same. Further, in steps S62 to S70 of FIG. 9, the time during which the receiving unit 12 does not wait for transmission data can be lengthened, and the power consumption can be further reduced by shutting off the power of the receiving unit 12.

  FIG. 14A is a functional block diagram of the receiving device 11 according to the second embodiment. With reference to FIG. 14A, the control unit 14 includes an error detection unit 104. A transmission unit 102 that notifies error detection is provided. Other configurations are the same as those in FIG. 3A of the first embodiment, and a description thereof will be omitted. FIG. 14B is a functional block diagram of the transmission device 21 according to the second embodiment. With reference to FIG. 14B, the control unit 24 includes a reception control unit 108. A receiving unit 106 that receives error detection is provided. Other configurations are the same as those of the first embodiment shown in FIG.

  15 and 16 are flowcharts illustrating the operation of the reception device 11 according to the second embodiment. Referring to FIGS. 15 and 16, after step S22 of FIG. 9 in the first embodiment, the error detection unit 104 determines whether or not there is an error in the received data (step S80 of FIG. 16). As an error detection method, for example, a CRC (Cyclic Redundancy Check) method is used. In the case of Yes, the transmission unit 102 notifies the transmission device 21 that there is an error in the received data (step S84). In No, step S24 of FIG. 9 is performed. The transmission unit 102 transmits the completion of processing to the reception device 11 (step S82). Other steps are the same as those of the first embodiment shown in FIG.

  17 and 18 are flowcharts illustrating the operation of the transmission apparatus 21 according to the second embodiment. Referring to FIGS. 17 and 18, if No in step S <b> 76 in FIG. 10, transmission control unit 25 determines whether reception unit 106 has received an error detection notification (step S <b> 90). In the case of No, similarly to steps S36 to S42 in FIG. 10, the same data is transmitted twice while changing the channel (step S92). In the case of Yes, the same data is transmitted three times while changing the channel (step S94).

  The reception control unit 108 determines whether the reception unit 106 has received a preamble (step S96). In the case of No, the reception control unit 108 causes the reception unit 106 to sweep the reception channel (step S98). The reception control unit 108 determines whether or not the specified reception time has elapsed (step S100). In No, it returns to step S96. In the case of Yes, it is determined that the transmission data has not arrived at the receiving device 11 or the notification from the receiving device 11 has not arrived at the transmitting device 21, it is determined that it is out of service area, and the process proceeds to step S 44. If Yes in step S96, the reception control unit 108 causes the reception unit 106 to fix the reception channel (step S102). The reception control unit 108 causes the reception unit 106 to receive response data from the reception device 11 (notifications in steps S82 and S84 in FIG. 10) (step S104). The reception control unit 108 detects an error in the response data (step S106). The control unit 24 turns on the LED 88 of FIG. 2 based on the result of the response data (step S108). Proceed to step S98.

  According to the second embodiment, as in step S84 in FIG. 16, the error detection unit 104 of the reception device 11 notifies the transmission device 21 when there is an error in the data received by the reception unit 12 in the reception control process. . As in step S94 of FIG. 17, when the transmission control unit 25 of the transmission device 21 receives information indicating that there is an error in the data received by the reception device 11 from the reception device 11, the transmission control unit 25 increases the number of channels. As a result, when the reception state of the reception device 11 is poor, the number of channels for transmitting transmission data to the transmission device 21 can be increased to improve the communication quality. When the error detection unit 104 detects an error in the received data, the number of channels can be increased sequentially. Further, when no error is detected in the data received by the error detection unit 104, the number of channels can be sequentially reduced.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims.・ Change is possible.

FIG. 1 is a block diagram showing an in-vehicle device. FIG. 2 is a block diagram illustrating the portable device. FIG. 3A is a functional block diagram of the receiving device, and FIG. 3B is a functional block diagram of the transmitting device. FIG. 4 is a flowchart illustrating the operation of the receiving device of the comparative example. FIG. 5 is a flowchart illustrating the operation of the transmission device of the comparative example. FIG. 6A and FIG. 6B are time charts of the receiving device of the comparative example. FIG. 7 is a time chart of the transmission device of the comparative example. FIG. 8A to FIG. 8D are time charts of comparative examples. FIG. 9 is a flowchart illustrating the operation of the receiving apparatus according to the first embodiment. FIG. 10 is a flowchart illustrating the operation of the transmission apparatus according to the first embodiment. FIG. 11A and FIG. 11B are time charts of the receiving apparatus according to the first embodiment. FIG. 12 is a time chart of the transmission apparatus according to the first embodiment. FIG. 13A to FIG. 13C are time charts of the first embodiment. FIG. 14A is a functional block diagram of the receiving apparatus according to the second embodiment, and FIG. 14B is a functional block diagram of the transmitting apparatus. FIG. 15 is a flowchart (part 1) illustrating the operation of the receiving apparatus according to the second embodiment. FIG. 16 is a flowchart (part 2) illustrating the operation of the receiving apparatus according to the second embodiment. FIG. 17 is a flowchart (part 1) illustrating the operation of the transmission apparatus according to the second embodiment. FIG. 18 is a flowchart (part 2) illustrating the operation of the transmission apparatus according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Receiving device 12 Receiving part 14 Control part 18 Power supply part 21 Transmitting apparatus 22 Transmitting part 24 Control part

Claims (15)

A transmission device for transmitting data using a plurality of channels having different frequencies;
A receiving unit that receives the data, and when the receiving unit does not receive the data for the first predetermined time or longer, the receiving unit uses a part of a plurality of channels and waits for the data in a part of a period. And then, when the receiving unit receives the data, the receiving unit uses the plurality of channels sequentially to receive the data, and the receiving unit uses the partial channel to transmit the data. A control unit that executes a power supply control process for cutting off power supply to the receiving unit in a period other than the partial period when waiting, and a receiving device,
A communication system comprising: The transmitter is
A transmitter that transmits the data to the receiver using any one of the plurality of channels;
When the transmission unit does not transmit the data for a second predetermined time or more, when the transmission unit transmits data using the partial channel, and then transmits another data within a third predetermined time, A control unit that causes the transmission unit to transmit the other data using another part of the plurality of channels;
The communication system according to claim 1, further comprising:   The communication system according to claim 1, wherein, in the reception control process, the control unit of the reception device notifies the transmission device when there is an error in the data received by the reception unit. In the reception control process, the control unit of the reception device notifies the transmission device when there is an error in the data received by the reception unit,
The control unit of the transmission device increases the number of the other partial channels when receiving information indicating that there is an error in data received by the reception device from the reception device. The communication system according to claim 2. The data includes a data body and a preamble transmitted before the data body,
The receiving unit waits for the preamble,
The said control part makes the said receiving part receive the said data main body using the channel which received the said preamble, when the said receiving part receives the said preamble in the said reception control process. Communications system.   A waiting time of one channel when the receiving unit waits for the data using the partial channel, and a waiting time of one channel when the receiving unit sequentially uses the plurality of channels to hold the data; The communication system according to claim 1, wherein the two are the same.   The communication system according to claim 6, wherein the data is data for controlling a vehicle. A receiving unit that receives data transmitted by the transmitting device using a plurality of channels having different frequencies;
When the receiving unit does not receive the data for the first predetermined time or more, the receiving unit is made to wait for the data in a part of a period using a part of a plurality of channels, and then the receiving unit receives the data. When the reception unit uses the plurality of channels sequentially to receive the data, and the reception unit waits for the data using the partial channel, the partial period A power supply control process for cutting off power supply to the receiving unit in a period other than
A receiving apparatus comprising:   The receiving device according to claim 8, wherein the control unit notifies the transmitting device when there is an error in the data received by the receiving unit in the reception control process. A transmission unit that transmits the data to the reception device using any of a plurality of channels having different frequencies;
When the transmission unit does not transmit the data for a second predetermined time or more, the transmission unit transmits data using a predetermined part of a plurality of channels, and the transmission unit transmits the predetermined part. When transmitting another data within a second predetermined time after transmitting the data on the other channel, the other data is transmitted to the transmitter using another part of the plurality of channels. A control unit,
A transmission device comprising:   The said control part increases the said another one part channel number, when the information which shows that there was an error in the data which the said receiving apparatus received from the said receiving apparatus is received. Transmitter. A control method of a communication system comprising: a transmission device that transmits data using a plurality of channels having different frequencies; and a reception device that includes a reception unit that receives the data,
When the receiving unit does not receive the data for the first predetermined time or longer, the receiving unit waits for the data in a part period using a part of a plurality of channels; and
Thereafter, when the receiving unit receives the data, the receiving unit sequentially uses the plurality of channels having different frequencies to hold the data;
Shutting off the power supply to the receiving unit in a period other than the partial period when the receiving unit waits for the data using the partial channel;
A control method for a communication system, comprising:   The method of controlling a communication system, wherein the data is data for controlling a vehicle. A control method of a receiving device including a receiving unit that receives data transmitted by a transmitting device using a plurality of channels having different frequencies,
When the receiving unit does not receive the data for the first predetermined time or longer, the receiving unit waits for the data in a part period using a part of a plurality of channels; and
Thereafter, when the receiving unit receives the data, the receiving unit sequentially uses the plurality of channels to receive the data;
Shutting off the power supply to the receiving unit in a period other than the partial period when the receiving unit waits for the data using the partial channel;
A control method for a receiving apparatus. A control method of a transmission device comprising a transmission unit that transmits the data to the reception device using any of a plurality of channels having different frequencies,
When the transmission unit does not transmit the data for a second predetermined time or more, the transmission unit transmits data using a predetermined part of a plurality of channels; and
When the transmission unit transmits the data on the predetermined part of the channel and then transmits another data within a second predetermined time, another part of the plurality of channels is transmitted to the transmission unit. Transmitting the other data using a plurality of channels;
A method for controlling a transmitting apparatus comprising:

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