JP4939977B2 - COMMUNICATION SYSTEM, BASE STATION USED FOR THE SAME, AND COMMUNICATION METHOD USED FOR THEM - Google Patents

Description

  The present invention relates to a communication system that communicates between a base station and a transmission / reception apparatus, a base station used therefor, and a communication method used therefor.

  Recently, control is performed to automatically open a vehicle door or start an engine by exchanging information between a base station attached to the vehicle and a portable device (key) as a transmission / reception device owned by the driver. The number of vehicles equipped with communication systems is increasing. In such a communication system installed in a vehicle, when information is exchanged between a base station provided in the vehicle and a portable device held by the driver, the portable device is basically prepared for start-up by a burst signal. After that, when the wake code signal is determined, it starts in earnest.

As such a communication system, for example, there is a system disclosed in Patent Document 1, which prevents a non-authorized person from starting an engine of a vehicle. In the communication system, the control device in the vehicle transmits an inquiry signal (request signal) when the start button in the vehicle is pressed, and then checks the identification code group transmitted by the remote control device of the authorized person. . Only when the identification code group matches the predetermined code group, the communication system allows the engine to start. The signal detector connected to the receiving antenna of the remote control device has a reaction threshold level that switches between a high value and a low value. The signal detector relays the inquiry signal and sends it to the next processing stage only when the inquiry signal level is higher than a predetermined reaction threshold.
JP 2001-354117 A

  However, in the conventional communication system, the mobile device always monitors the presence or absence of a request signal, and determines the burst signal included in the request signal when reception of the request signal is started. After determining the burst signal, the portable device is ready to start and enters a mode for receiving a wake code. Therefore, when the mobile device misidentifies the external noise as a burst signal, the mobile device enters a mode for receiving a wake code, and there is a problem that even if a normal burst signal is received thereafter, the burst signal cannot be judged well.

  The present invention has been made to solve the conventional problems, and provides a communication system capable of correctly determining a regular request signal even when there is external noise, and a base station used therefor and a communication method used therefor The purpose is to provide.

The base station of the present invention is a base station for transmitting a request signal for controlling the activation of unrealized transceiver a first code signal subsequent to the at least the burst signal and the burst signal to the transceiver, the request A transmission unit that transmits a signal to the transmission / reception device, a reception unit that receives a response signal corresponding to the request signal from the transmission / reception device, and outputs the request signal to the transmission unit, and the response signal is the reception unit A control unit that is input via the control unit, wherein the control unit outputs a second code signal for resetting the transmission / reception device together with the request signal, and the transmission unit outputs the second code signal to the second code signal. Subsequently, the request signal is transmitted to the transmitting / receiving device.

With this configuration, even when the transmission / reception apparatus receives continuous noise signals, it is possible to correctly determine a normal request signal and obtain a good reception result. That is, it is possible to prevent the transmission / reception apparatus from being inadvertently woken up and to improve the noise toughness of the transmission / reception apparatus .

In the base station of the present invention, the control unit sets the transmission time of the burst signal to be longer than a timeout time that is a reception waiting time of the first code signal in the transmission / reception apparatus .

With this configuration, by transmitting the burst signal included in the request signal within the timeout time, the transmission / reception apparatus can correctly determine the burst signal and obtain a good reception result.

Further, in the base station of the present invention, the control unit sets the time from the off state where the second code signal is not output to the start of transmission of the burst signal to be shorter than the timeout time. To do.

  With this configuration, transmission of a burst signal is always started within the timeout time.

Furthermore, the base station of the present invention is connected to the transmission unit includes a first transmission antenna and the second transmit antennas having different directivity from one another, and the transmission unit, the Ri by the second transmit antenna after transmitting the second code signal, and outputs the first second code signal and the request signal Ri by transmitting antennas.

  With this configuration, it is possible to further increase the possibility of obtaining a good reception result by transmitting the burst signal after the base station transmits the second code signal from the plurality of transmission antennas.

The communication system of the present invention includes a base station for transmitting a request signal for controlling the activation of unrealized transceiver a first code signal following the burst signal and the burst signal, receiving the request signal, said transceiver of changing the receiving mode, a communication system constituted by the base station, a second code signal for resetting the receive mode of the transceiver, to the second code signal Subsequently, the transmission / reception apparatus set to a mode for transmitting the request signal to the transmission / reception apparatus and receiving the burst signal is configured to detect the first state based on detection of an off state in which the second code signal is not output . The mode is changed to a mode for receiving the burst signal, and after the elapse of a timeout time which is a waiting time for receiving the first code signal, the mode is changed to a mode for receiving the burst signal. To.

  With this configuration, even when a continuous noise signal is received, a proper request signal can be correctly determined, and a good reception result can be obtained.

In the communication system, the base station sets the transmission time of the burst signal to be longer than a timeout time that is a reception waiting time of the first code signal in the transmission / reception apparatus .

With this configuration, by transmitting the burst signal included in the request signal within the timeout time, the transmission / reception apparatus can correctly determine the burst signal and obtain a good reception result.

The communication method of the present invention is a communication method for performing communication between a base station and a transmission / reception device, wherein the base station resets a reception mode of the transmission / reception device, and the second code signal, Following the code signal to perform the step of transmitting a request signal for controlling the activation of unrealized transceiver and a burst signal prior to at least a first code signal and the first code signal to the transceiver device, the transceiver device, and receiving the second code signal, and detecting the off-state in which the second code signal is not output, the off-state of the second code signal is not output After detecting, the step of shifting to the mode for receiving the burst signal, and the time for receiving the first code signal after shifting to the mode for receiving the burst signal. After the lapse of timeout time, it executes the steps of transition to a mode of receiving the burst signal.

With this communication method, even when the transmission / reception apparatus receives continuous noise signals, it is possible to correctly determine a normal request signal and obtain a good reception result.

  The present invention provides a communication system that can correctly determine a legitimate request signal even when there is external noise, and a base station used therefor, and a communication method used therefor.

  Hereinafter, a communication system according to an embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
A communication system according to a first embodiment of the present invention is shown in FIG.

  In FIG. 1, the communication system 1 is configured to include a base station 10 provided in a vehicle and a portable device 20 possessed by a driver. In addition, a noise source 30 exists in the vicinity of the communication system 1 as an external noise source for the communication system 1. The portable device 20 includes, for example, a vehicle key, but a specific example is not particularly limited. In this example, the communication partner of the base station 10 is a portable device, but is not limited to a portable device, and may be a general transmission / reception device.

  The base station 10 includes a control unit 11, a transmission unit 12 and a reception unit 15 connected to the control unit 11. The transmission unit 12 is connected to a first transmission antenna 13 and a second transmission antenna 14 formed by loop coils. In the figure, the first transmission antenna 13 has a coil wound in the left-right direction, and the second transmission antenna 14 has a coil wound in a direction perpendicular to the paper surface. This indicates that the directivity of the two transmission antennas, particularly the relative directivity with respect to the mobile device 20 of the communication partner is different. However, since the relative directivities of the two transmitting antennas with respect to the portable device 20 are different depending on the installation location of the antennas, it is not essential to change the winding method of the coils. That's fine. In the present embodiment, the directivity difference is not essential.

  When communicating with the mobile device 20, the base station 10 outputs a request signal for requesting an answer from the mobile device 20 from the transmission antenna 13 or 14, including a wake code signal and a burst signal. Here, for convenience of explanation, description is made using two antennas, but actually, three or more antennas may be used.

  The receiving unit 15 is connected to the receiving antenna 16 and receives a signal from the portable device 20 via the receiving antenna 16.

  As will be described later, the control unit 11 performs control so that a request signal including at least a burst signal and a wake code signal following the burst signal is output via the transmission unit 12 and the transmission antenna 13 or 14 following the dummy signal. . The request signal is a signal for the base station 10 to authenticate the mobile terminal 20, and the mobile terminal 20 shifts to various different modes according to the content of the wake code signal of the request signal. Further, the determination result from the base station 10 is received using the receiving unit 15 and the receiving antenna 16 connected to the receiving unit 15, and the subsequent control is changed according to the result.

  The burst signal is a signal for starting up the receiving unit 22, in particular, the circuit operation of the portable device 20 in the sleep mode (standby state) when the power is on but the receiving unit 22 is not particularly operating. The portable device 20 is shifted to the operation mode. The burst signal contains no code and is not modulated at all. The burst signal is composed of a continuous on signal of, for example, 2 ms or more, and generates starting power in a circuit constituting the receiving unit 22 by the action of electromagnetic induction or the like. However, the form is not particularly limited.

  The wake code signal is a signal transmitted after the burst signal, includes a meaningful code, and constitutes the first code signal. The burst signal and the wake code signal constitute a request signal for requesting some answer from the portable device 2. The wake code signal includes, for example, a signal that an ON signal of 150 μs indicates “bit 0” and an ON signal of 300 μs indicates “bit 1”. The receiving unit 22 of the portable device 20 determines the meaning of the code of the wake code signal and determines whether or not the subsequent operation can be continued. That is, the wake code signal is a signal for starting the determination operation of the receiving unit 22. In this example, the wake code signal is composed of an AM-modulated signal in the 125 kHz band, but the frequency band and modulation method are not particularly limited.

  In the present invention, the dummy signal serves to release the reception unit 22 of the portable device 20 from being in a state of waiting for interruption of the burst signal, and consequently resets the operation of the reception unit 22 and the portable device 20. Since the dummy signal does not need to distinguish between “bit0” and “bit1”, the dummy signal includes a meaningless code and forms a second code signal. In this example, like the wake code signal, the dummy signal is also composed of an AM-modulated signal of, for example, 125 kHz band, but the frequency band and the modulation method are not particularly limited. In addition, a signal consisting of only 1 bit, a continuous long signal (multi-bit signal), and a signal including a plurality of combinations of continuous long signals can be included in the dummy signal here, but it is always “off” as described later. (A and B in FIG. 2D).

  On the other hand, the portable device 20 includes a control unit 21, a reception unit 22, a reception antenna 23 and a reception antenna 24 connected to the reception unit 22, a transmission unit 25, and an antenna 26 connected to the transmission unit 25.

  The request signal transmitted from the transmission antenna 13 or the antenna 14 of the base station 10 is received by the reception antennas 23 and 24. The receiving antennas 23 and 24 are formed of loop coils, and when a request signal is received, an induced voltage is generated according to the received electric field strength and input to the receiving unit 22. The directivities of the reception antennas 23 and 24 are also different from those of the first transmission antenna 13 and the second transmission antenna 14, but are not essential in the present embodiment.

  The receiving unit 22 includes an antenna switching unit 221 that enables one of the receiving antennas 23 and 24 according to the received signal level, a demodulating unit 222 that demodulates the received AM-modulated request signal into a digital signal, and a demodulating unit. A wake code signal determination unit 223 that determines whether or not the digital signal demodulated in 222 matches a predetermined code, and transmits a determination result notification signal to the control unit 21 if it matches.

  In response to the determination result notification signal from the wake code signal determination unit 223, the control unit 21 uses a 300 MHz band radio wave, for example, via the transmission unit 25 and the transmission antenna 26 connected to the transmission unit 25. Is transmitted to the base station 10.

  FIG. 2 shows the waveform of the request signal and the noise signal from the noise source 30 in the present embodiment. Here, the waveform is described as the reception waveform of the reception antennas 23 and 24 of the portable device 20.

  2A is a diagram illustrating an induced voltage waveform when the request signal S1 is received when the dummy signal is added in the present embodiment, and FIG. 2B is a diagram illustrating noise generated when the noise signal S2 is received. It is a figure which shows an example of a waveform, (c), (d) shows the induced voltage waveforms S3 and S4 of the receiving antennas 23 and 24 when the request signal S1 is received under a noise environment (under reception of S2), respectively. FIG.

 Further, (e) is a diagram showing an induced voltage waveform when the request signal S5 is received when no dummy signal is added, unlike (a) of the present embodiment, and (f), (g) These are the figure which shows the induced voltage waveforms S6 and S7 of the receiving antennas 23 and 24 when only the noise signal shown in (b) and the request signal S5 shown in (e) are received.

  T1 shown in FIG. 2D is a transmission time of the burst signal 51g (burst signal transmission time), and t3 is after the burst signal is interrupted until the mobile terminal 22 receives the wake code signal from the base station 10. , A time for waiting for reception of the wake code signal (wake code signal reception timeout time), which is registered in the portable device 20 in advance. t4 is the time from the time when the dummy signal 56g is in the first off state A to the beginning of transmission of the burst signal 51g (if there are a plurality of off states), and is shorter than the wake code signal reception timeout time t3. (T4 <t3).

  t2 is the transmission time of the wake code signal 52g (wake code signal transmission time). Further, t5 is a time for transmitting the burst signal 51g after the elapse of the wake code signal reception timeout time t3. In this example, the relationship of t2 <t3 <t1 is established. Further, A and B shown in FIGS. 2A to 2D indicate the OFF state of the dummy signal. The length of t5 is arbitrary, but at least t5 must be present, and t5> 0.

  FIG. 3A is an enlarged view of the waveform of the request signal in FIG. 2 and is a 125 kH modulated signal. On the other hand, FIG. 3B shows an enlarged waveform of noise in FIG. 2 and is a random signal with an indefinite frequency.

  Here, for example, in FIG. 1, the receiving antenna 23 is arranged to face the transmitting antenna 13, and the receiving antenna 24 is arranged to face the noise source 30. Accordingly, the induced voltages 51f and 51h when the request signal S1 shown in (a) is received by the receiving antenna 23 are larger than the induced voltages 51g and 51i when received by the receiving antenna 24. Conversely, the induced voltages 54f and 54h when the noise signal S2 shown in (b) is received by the receiving antenna 23 are smaller than the induced voltages 54g and 54i when received by the receiving antenna 24. When the receiving unit 22 receives the request signal S5 when the dummy signal 56 shown in (e) is not added under the noise environment shown in (b), the receiving unit 22 converts the noise into a burst signal. However, when noise is received, the signal level 54g of the reception antenna 24 is higher than the signal level 54f of the reception antenna 23, so the reception antenna 24 is selected.

  Thereafter, the process shifts to a burst signal interruption detection process. However, as shown in (g), after starting the process with the signal 54i, the burst level of the signal 51i cannot be detected because the level of the signal 51i only rises. The end of 51i is processed as a burst interruption. Thereafter, the wake code reception determination is performed. However, since 24 is still selected as the reception antenna, the wake code signal 52i having the induced voltage waveform shown in (g) is determined, and the S / N ratio is poor. There is a problem that a reception error is likely to occur.

  Therefore, in the present embodiment, as indicated by the request signal S1, the base station 10 transmits the dummy signal 56e from the transmission antenna 13 or 14, and then carries the burst signal 51e, the wake code signal 52e, and the code signal 53e in this order. This is configured to transmit to the device 20.

  When the portable device 20 receives the request signal S1 and the noise signal S2, the induced voltage waveforms of the receiving antennas 23 and 24 are as shown in (c) and (d), respectively.

  The receiving unit 22 receives the noise signal S2 and starts the operation by regarding the noise signal as a burst signal (starting reception of the burst signal; reception mode of the burst signal). At this time, from the signal level 54f of the receiving antenna 23 Since the signal level 54g of the receiving antenna 24 is higher, the receiving antenna 24 is selected.

  Thereafter, the receiving unit 22 proceeds to a burst signal interruption detection process. Here, since the receiving unit 22 regards the noise signal as a burst signal, when the off of the dummy signal 56g is detected, it is determined that the burst signal is interrupted, and the process proceeds to a wake code signal reception process (a wake code signal reception mode). The wake code signal is determined for the dummy signal 56g and the burst signal 51g after the off state is detected. In this example, there are two dummy signal OFF states as shown in FIGS. 2A to 2D, but the wake code signal reception timeout, which is the WAIT code signal reception waiting time, from the first A OFF state. Counting of time t3 is started. Since t4 <t3, the burst signal 51g is transmitted from the middle of counting the wake code signal reception timeout time t3.

  In the middle of the transmission time t1 of the burst signal 51g, the wake code signal reception timeout time t3 expires. Accordingly, the receiving unit 22 interrupts the wake code signal determination process in the middle of the burst signal 51g, returns to the burst signal reception wait, and starts again (re-transition to the burst signal reception mode). Since the timeout time is counted when the dummy signal 56g is turned off, the dummy signal 56g serves to reset the reception mode of the portable device 20.

  At this time, since the signal level 51f of the receiving antenna 23 is higher than the signal level 51g of the receiving antenna 24, the receiving antenna 23 is selected, and after the burst signal 51f ends, the wake code signal 52f having the induced voltage waveform shown in FIG. (Wake code signal reception mode). Since the wake code signal at this time has a high signal level from the transmission antenna 13 or 14 and a high S / N ratio, a better reception result is obtained than the wake code signal 52g having the induced voltage waveform shown in (d). It is done.

  The operation of the communication system configured as described above will be described with reference to FIG.

  First, the mobile device 20 stands by in a burst signal waiting state (step S301). Here, when the receiving unit 22 of the mobile device 20 determines whether there is a request signal from the base station 10 and determines that there is no request signal from the base station 10 (step S301; NO), step S301 is repeatedly executed. And waits for a request signal from the base station 10.

  On the other hand, when it is determined in step S301 that the receiving unit 22 has received the request signal from the base station 10 (step S301; YES), reception of the burst signal is started (step S302). Here, in the first determination, the first 54g portion of the noise signal S4 shown in FIG. 2 (d) has a higher signal level than the first 54f portion of the request signal S3 shown in FIG. 2 (c). Therefore, the portable device 20 determines the 54g portion as a burst signal and starts receiving the burst signal.

  The receiving unit 22 includes an AGC (Automatic Gain Control) circuit, and the antenna switching unit 221 of the receiving unit 22 switches between the receiving antenna 23 and the receiving antenna 24 and detects each signal level. The antenna with the higher signal level is selected (step S303). Here, as described above, since the first burst signal is received with respect to a noise signal having a relatively high level, the reception antenna 24 that receives this noise signal is selected.

  Thereafter, the receiving unit 22 determines whether or not the burst signal has been interrupted (step S304). If it is determined that the burst signal has not been interrupted (step S304; NO), step S304 is repeatedly executed to interrupt the burst signal. wait.

  On the other hand, if it is determined in step S304 that the burst signal has been interrupted, the receiving unit 22 receives the wake code signal that is the first half of the request signal input subsequent to the burst signal (step S305). Here, after the antenna switching unit 221 selects a reception antenna, the process proceeds to a burst signal interruption detection process, and the dummy signal 56g is detected to be off and the process proceeds to a wake code signal reception process. A wake code signal is determined for the signal 51g.

  Subsequently, the wake code signal determination unit 223 determines whether reception of the wake code signal has been completed (step S306). If it is determined that reception of the wake code signal has not been completed (step S306; NO), a predetermined value is determined. It is determined whether the time-out period has elapsed (step S307). If it is determined that the predetermined time-out period has not elapsed (step S307; NO), the process returns to step S305 to continue receiving the wake code signal.

  On the other hand, when the wake code signal determination unit 223 determines in step S307 that the predetermined timeout time has elapsed (step S307; YES), the reception cannot be completed even after the predetermined timeout time has elapsed, and it is determined as a reception error. Then, the process returns to step S301 and waits in a burst signal waiting state. Here, since the transmission time t1 of the burst signal 51e is longer than the wake code signal reception timeout time t3, the wake code signal determination processing (step S305 to step S307) is interrupted in the middle of the burst signal 51e, and the burst signal reception wait (step Returning to S301), the operation is started again.

  When returning to step S301 again, since the base station 10 transmits the request signal S1 when the dummy signal shown in FIG. 5A is added, what is received at this time is included in this request signal. Part of the burst signal.

  At this time, if it is determined in step S301 that the request signal from the base station 10 has been received (step S301; YES), reception of the burst signal is started (step S302), and the antenna switching unit 221 of the receiving unit 22 causes the burst signal period. The receiving antenna 23 and the receiving antenna 24 are switched between 51, the respective signal levels are detected, and the antenna with the higher signal level is selected (step S303). Here, since the receiving antenna 23 is arranged to face the transmitting antenna 13 and the receiving antenna 24 is arranged to face the noise source 30, the receiving antenna 23 is a burst from the base station 10. The signal is mainly received, and the receiving antenna 24 is in a state of mainly receiving the noise signal from the noise source 30. That is, the induced voltage of the receiving antenna 23 is 51f, and the induced voltage of the receiving antenna 24 is 51g. Since the signal level 51f of the receiving antenna 23 is higher than the signal level 51g of the receiving antenna 24, the antenna switching unit 221 selects the receiving antenna 23.

  Thereafter, the receiving unit 22 determines whether or not the burst signal has been interrupted (step S304). If it is determined that the burst signal has not been interrupted (step S304; NO), step S304 is repeatedly executed to interrupt the burst signal. wait.

  On the other hand, when the receiving unit 22 determines in step S304 that the burst signal has been interrupted (step S304; YES), the receiving unit 22 receives the wake code signal that is the first half of the request signal that is input following the burst signal. Is received (step S305). Here, the demodulator 222 converts the wake code 52f into an I / O bit data string, and the wake code signal determination unit 223 determines the wake code 52f. In this embodiment, a short pulse (for example, 0.5 ms or less) is determined as bit 0, and a long pulse (for example, 0.5 ms or more) is determined as bit 1.

  The wake code signal determination unit 223 determines whether reception of the wake code signal has been completed (step S306). If it is determined that reception of the wake code signal has not been completed (step S306; NO), a predetermined timeout time is set. It is determined whether or not a predetermined time-out period has elapsed (step S307; NO), the process returns to step S305, and the wake code signal is continuously received.

  On the other hand, when the wake code signal determination unit 223 determines in step S307 that the predetermined timeout time has elapsed (step S307; YES), the reception cannot be completed even after the predetermined timeout time has elapsed, and it is determined as a reception error. Then, the process returns to step S301 and waits in a burst signal waiting state.

  In step S306, when it is determined that the wake code signal determination unit 223 has received the predetermined number of bits (step S306; YES), it is assumed that reception of the wake code signal is completed, and the wake code signal determination unit 223 receives the signal. If the received wake code is not a regular code (step S308; NO), the process returns to step S301 and waits in a burst signal waiting state. To do.

  On the other hand, when it is determined in step S308 that the received wake code is a regular code (step S308; YES), the wake code signal determination unit 223 notifies the control unit 21 of the determination result (step S309), and the control unit 21 starts driving upon reception of the signal, determines whether to receive the code signal 53f after the wake code signal 52f, and transmits a response signal to the base station 10 via the transmitter 25 according to the determination result (step). S310). Then, the process ends.

  As described above, in the present invention, the reception of the mobile device is reset by transmitting the dummy signal in consideration of the case where the mobile device enters the mode of receiving the wake code by misinterpreting the noise signal as the burst signal. To do. Even when a continuous noise signal is received, after detecting the OFF portion of the dummy signal as the burst signal OFF, the AGC in the portable device during the period when the regular burst signal is transmitted from the transmission antenna of the base station. Since operation and antenna selection are performed, an antenna with a good S / N ratio can be selected when a code signal is received thereafter, a proper request signal can be correctly determined, and a good reception result can be obtained.

  In the present invention, the burst signal transmission time t1 is set longer than the wake code reception waiting time-out time t3 (t3 <t1). Therefore, even if the receiving unit 22 of the mobile device 20 starts to operate due to noise, the wake code signal determination process is once ended within the burst signal transmission time t1, the burst signal reception is started again, and the reception signal level is large. Since an antenna can be selected, malfunction under a noisy environment can be prevented. In FIG. 2, the start point of the wake code reception waiting time-out time t3 comes before the start point of the burst signal transmission time t1. However, since the time-out time of the wake code signal starts to be counted before the start of reception of the normal burst signal, the burst signal transmission time t1 is set longer than the wake code reception waiting time-out time t3. A timeout always occurs during the reception of the burst signal.

  In the above description, an example in which two transmission antennas are used on the base station 10 side has been described. However, in the present embodiment, it is not essential to use two transmission antennas on the base station 10 side. A similar effect can be obtained with an antenna.

  In the above description, an example in which the length of the burst signal is increased has been described. However, in the present embodiment, this is not essential, and a similar effect can be obtained even with a short burst signal.

(Second Embodiment)
Next, a communication system according to the second embodiment of this invention will be described.

  In the present embodiment, the transmission unit 12 of the base station 10 is provided with a plurality of transmission antennas 13 and 14, and the control unit 11 follows the second dummy signal transmission from the second transmission antenna, and then from the first transmission antenna. The first dummy signal and the request signal are output.

  The configuration of the communication system of this embodiment is the same as that of the first embodiment shown in FIG.

  FIG. 5 shows the waveform of the request signal and noise in the present embodiment, and here, description will be made as the received waveform of the receiving antenna as in FIG.

  In FIG. 5, (a), (b), (c), and (d) correspond to (a), (b), (c), and (d) in FIG. In this example, the noise source 30 is close to the transmission antenna 26, and the noise shown in FIG. 5B is larger than the noise described in FIG. That is, in this example, the request signal is buried in noise in the second half of the induced voltage waveform diagram (d) of the receiving antenna 24 when the request signal is received in a noise environment where the noise signal 54k exists, and the on / off state is determined. This is an example that cannot be distinguished. Further, the receiving antenna 24 has a lower relative directivity to the first transmitting antenna 13 than the receiving antenna 23, and the sensitivity of the dummy signal 56 transmitted from the first transmitting antenna 13 is low.

  A signal S5 shown in FIG. 5E is a dummy signal transmitted from the transmission antenna 14 prior to the transmission of the request signal S1 shown in FIG.

  When the receiving unit 22 is placed in a noise environment as shown in FIG. 5B, the antenna switching unit 221 of the receiving unit 22 selects the antenna 24 having a high induced voltage, and the receiving unit 22 bursts noise. Processing starts as a signal.

  If there is no dummy signal S5 shown in FIG. 5 (e), the level of the noise signal 54k is high and there is not much difference from the level of the dummy signal 56k. The unit 22 may not be able to detect the off state of the dummy signal 56k. In this case, it is impossible to shift to the wake code signal reception process, and the mobile terminal 20 cannot perform an appropriate operation.

  Therefore, in the present embodiment, prior to the dummy signal 56k, the dummy signal 57k is transmitted from the second transmission antenna 13 having high preference for the reception antenna 24. Then, the receiving unit 22 detects that the dummy signal 57k received by the receiving antenna 24 is turned off, shifts to a wake code signal reception process, and determines the wake code signal for the dummy signal 56k and the burst signal 51k. Then, the receiving unit 22 interrupts the wake code signal determination process in the middle of the burst signal 51k, returns to waiting for the burst signal reception, and starts again.

  At this time, since the signal level 51j of the receiving antenna 23 is higher than the signal level 51k of the receiving antenna 24, the receiving antenna 23 is selected, and after the burst signal 51j ends, the wake code signal 52j of the induced voltage waveform (c) is determined. . At this time, the signal level from the transmission antenna 13 is high and the S / N ratio is also high, so that a better reception result than the wake code signal 52k in the induced voltage waveform FIG.

  The processing operation of this embodiment is the same as that of the first embodiment shown in FIG.

  In this way, the base station transmits a dummy signal from each of a plurality of transmission antennas having different directivities, and then transmits a burst signal, thereby further increasing the possibility of obtaining a good reception result.

  The present invention is useful for a communication system between a base station and a portable device that is easily affected by external noise, such as a vehicle remote control device, but the application example is not particularly limited.

  Although various embodiments of the present invention have been described, the present invention is not limited to the matters shown in the above-described embodiments, and those skilled in the art may modify or apply the description based on the description of the specification and well-known techniques. The present invention is intended to be included in the scope for which protection is sought.

  As described above, according to the communication system according to the present invention, the base station used in the communication system, and the communication method, it is possible to correctly determine the legitimate request signal in the portable terminal even when there is external noise.

1 is a block diagram of a communication system according to a first embodiment of this invention. The figure which shows the waveform of the request signal and noise in the 1st Embodiment of this invention The figure which shows a mode that the request signal and noise signal in FIG. 2 were expanded. The flowchart for demonstrating operation | movement of the portable apparatus of the communication system in the 1st Embodiment of this invention. The figure which shows the waveform of the request signal and noise in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 10 Base station 11,21 Control part 12,25 Transmission part 13,14,26 Transmission antenna 15,22 Reception part 16,23,24 Reception antenna
20 mobile device 30 noise source 221 antenna switching unit 222 demodulation unit 223 wake code signal determination unit

Claims (7)

A base station for transmitting at least a request signal for the first code signal following the burst signal and the burst signal controls the activation of unrealized transceiver to the transceiver,
A transmission unit for transmitting the request signal to the transmission / reception device;
A receiving unit for receiving a response signal corresponding to the request signal from the transmission / reception device;
A controller that outputs the request signal to the transmitter and the response signal is input via the receiver;
The control unit outputs a second code signal for resetting the transmission / reception device together with the request signal, and the transmission unit transmits the request signal to the transmission / reception device following the second code signal. Bureau. The base station according to claim 1, wherein
The base station configured to set the transmission time of the burst signal to be longer than a timeout time that is a reception waiting time of the first code signal in the transmission / reception apparatus . The base station according to claim 2, wherein
The control unit is a base station configured to set a time from an off state where the second code signal is not output to a start of transmission of the burst signal to be shorter than the timeout time. The base station according to any one of claims 1 to 3,
The base station includes a first transmission antenna and a second transmission antenna that are connected to the transmission unit and have different directivities, and the transmission unit receives the second code signal from the second transmission antenna. After transmitting, a base station that outputs the second code signal and the request signal from the first transmission antenna. And a base station for transmitting a request signal for controlling the activation of unrealized transceiver a first code signal subsequent to the at least the burst signal and the burst signal, receiving the request signal, the transceiver device for changing the receiving mode A communication system comprising:
The base station transmits a second code signal for resetting the transmission / reception device and the request signal following the second code signal to the transmission / reception device,
The transmission / reception apparatus set to the mode for receiving the burst signal shifts to the mode for receiving the first code signal based on detection of an off state in which the second code signal is not output , and the first code signal is received. Transition to a mode for receiving the burst signal after elapse of a timeout time which is a reception waiting time of the code signal of 1.
Communications system. The communication system according to claim 5, wherein
The base station is configured to set the transmission time of the burst signal to be longer than a timeout time that is a reception waiting time of the first code signal in the transmission / reception apparatus . A communication method for performing communication between a base station and a transmission / reception device,
The base station is
A second code signal for resetting the receive mode of the transceiver, activation of the subsequent second following the code signals at least the burst signal and the burst signal first code signal and the unrealized said transceiver Performing a step of transmitting a request signal to control the transmitter / receiver to the transmitter / receiver,
The transmitting / receiving device is
Receiving the second code signal;
Detecting an off state in which the second code signal is not output ;
Transitioning to a mode for receiving the burst signal after detecting an off state in which the second code signal is not output ; and
A transition to a mode for receiving the burst signal, and a transition to a mode for receiving the burst signal after elapse of a timeout time which is a reception waiting time of the first code signal.