JP6077406B2 - COMMUNICATION CONTROL DEVICE, PORTABLE DEVICE, AND COMMUNICATION CONTROL METHOD - Google Patents

Description

  The present invention relates to a communication system.

  2. Description of the Related Art A function of an automobile that can lock and unlock a vehicle door and start an engine without using a mechanical key is known. This function is also called a smart entry & start system.

  In the smart entry and start system, communication is performed between a portable device (key) and an electronic control unit (ECU) and a body control module (BCM) mounted on the vehicle. When communication is established between the portable device and the electronic control unit or body control module, the door can be locked or unlocked and the engine can be started.

  Furthermore, a portable device having an interface for transmitting / receiving information to / from a mobile phone or a personal computer has been developed. This interface employs Near Field Communication (NFC). Some NFCs are internationally standardized as ISO14443.

  A system that responds by changing the output of a portable device based on a request signal transmitted from the portable device is known (see, for example, Patent Document 1).

JP 2007-77640 A

  When an RF (Radio Frequency) signal is transmitted from a portable device while the portable device is held over the portable terminal, the output may be attenuated due to the influence of a metal part of the portable terminal. When the output of the RF signal from the portable device is attenuated, the communication area by the portable device may be reduced. Due to the reduction of the communication area of the portable device, the vehicle may not be controlled by the RF signal from the portable device. Specifically, even if the portable device transmits a response signal to the request signal from the in-vehicle device, the in-vehicle device may not be received.

  The degree of influence on the output of the RF signal from the portable device varies depending on how the portable device is held. That is, the attenuation amount of the RF signal output from the portable device varies depending on how the portable device is held. As a result, if an RF signal is transmitted from the portable device while the portable device is held over the portable terminal, the RF signal output from the portable device is attenuated and becomes unstable, which is not preferable.

  Further, when RF signals are transmitted from the portable device without holding the portable device over the portable terminal, if the output intensity is increased, the current consumption of the portable device may increase and the battery life may be shortened.

  The present invention is to reduce the influence caused by attenuation of an RF signal transmitted from a portable device.

A communication control apparatus according to an embodiment of the disclosure includes:
A communication control device included in a portable device capable of short-range wireless communication with a portable terminal,
An RF signal transmitter for transmitting an RF signal;
The portable device and the said short-range wireless communication with the portable terminal is executed, and when the transmission of the RF signal is performed, a current measurement for measuring a current generated in the short-range wireless communication antenna Circuit,
Based on the measurement results of the current by said current measuring circuit, and a control unit for controlling the output intensity of the RF signal.

A portable device according to an embodiment of the disclosure is:
An RF signal transmitter for transmitting an RF signal;
A near field communication unit that performs near field communication;
A current measuring circuit that measures a current generated in the antenna of the short-range wireless communication when the short-range wireless communication and transmission of the RF signal are being executed;
Based on the measurement results of the current by said current measuring circuit, and a control unit for controlling the output intensity of the RF signal by the RF signal transmitting unit.

A communication control method according to an embodiment of the disclosure is as follows.
A communication control method executed by a communication control device included in a portable device capable of performing short-range wireless communication with a portable terminal,
An RF signal transmission step of transmitting an RF signal;
The portable device and the said short-range wireless communication with the portable terminal is executed, and when the transmission of the RF signal is performed, a current measurement for measuring a current generated in the short-range wireless communication antenna Steps ,
Based on the measurement results in said current measuring step, and a control step of controlling the output intensity of the RF signal.

  According to the disclosed embodiment, it is possible to reduce the influence caused by attenuation of the RF signal transmitted from the portable device.

It is a figure which shows one Example of a communication system. It is a figure which shows one Example of a portable terminal. It is a figure which shows one Example of a portable device. It is a figure which shows one Example of a portable device. It is a flowchart which shows one Example of operation | movement of a communication system. It is a figure which shows the effect by one Example of a communication system.

Next, the form for implementing this invention is demonstrated, referring drawings based on the following Examples. Examples described below are merely examples, and embodiments to which the present invention is applied are not limited to the following examples.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

<Example>
<Communication system>
FIG. 1 shows an embodiment of a communication system.

  The communication system includes an in-vehicle device (not shown) mounted on a moving body such as the vehicle 1, a mobile terminal 200, and a mobile device 300. The mobile terminal 200 is a reader / writer, a mobile phone, a smartphone, a mobile information terminal, or the like.

  In one embodiment of the communication system, the in-vehicle device is mounted on a vehicle. The portable terminal 200 and the portable device 300 are preferably carried by the user. By holding the portable device 300 over the portable terminal 200, wireless communication is performed between the portable device 300 and the portable terminal 200 by the short-range wireless communication technology. By holding the portable device 300 over the portable terminal 200, data from the portable terminal 200 can be wirelessly transmitted from the portable device 300 to the in-vehicle device. For example, as data from the portable terminal 200, there is a function that is preinstalled in the in-vehicle device, such as setting information of the volume of the vehicle answer back.

  When data from the portable terminal 200 is wirelessly transmitted by the portable device 300, the intensity value of the RF signal output from the portable device 300 may be attenuated due to the influence of the portable terminal 200. When the output intensity value of the RF signal output from the portable device 300 is attenuated, the communication area of the portable device 300 may be reduced.

  One embodiment of the portable device 300 grasps the degree of influence of the portable terminal 200 on the output RF signal. The portable device 300 adjusts the output of the RF signal based on the degree of influence.

<Mobile terminal 200>
FIG. 2 shows an embodiment of the mobile terminal 200.

  The mobile terminal 200 has a short-range wireless communication unit 202. The near field communication unit 202 performs wireless communication with the portable device 300 using near field communication (NFC) technology. The short-range wireless communication unit 202 performs wireless communication according to ISO / IEC 14443 Type A. The short-range wireless communication unit 202 may perform wireless communication according to FeliCa, or may perform wireless communication according to ISO / IEC 14443 Type B and ISO / IEC 15693. One embodiment of the short-range wireless communication unit 202 includes an RFID reader / writer. In this case, the short-range wireless communication unit 202 transmits a radio signal in the HF (High Frequency) band having a frequency of 13.56 MHz.

<Mobile device 300>
FIG. 3 shows an embodiment of the portable device 300.

  The portable device 300 includes a portable device control unit 302, an LF signal reception unit 310, a short-range wireless communication unit 312, and an RF signal transmission unit 318.

  The LF signal receiving unit 310 receives an LF (Low Frequency) signal from the in-vehicle device via the LF antenna 309. The request signal is modulated into an LF band radio wave by the in-vehicle device, and is transmitted wirelessly via the transmission antenna. The LF signal receiving unit 310 receives the modulated signal and inputs it to the portable device control unit 302.

  The short-range wireless communication unit 312 performs wireless communication with the mobile terminal 200 using a short-range wireless communication technique. The short-range wireless communication unit 312 performs wireless communication according to ISO / IEC 14443 Type A. The short-range wireless communication unit 312 may perform wireless communication according to FeliCa, or may perform wireless communication according to ISO / IEC 14443 Type B and ISO / IEC 15693. One embodiment of the short-range wireless communication unit 312 includes an RFID reader / writer.

  The short-range wireless communication unit 312 includes an HF signal transmission / reception unit 314 and a current measurement circuit 316.

  The HF signal transmission / reception unit 314 transmits an HF band radio signal having a frequency of 13.56 MHz from the HF antenna 311. The HF signal transmission / reception unit 314 receives an HF band radio signal from the mobile terminal 200 via the HF antenna 311 and inputs the radio signal to the mobile device control unit 302.

  The current measurement circuit 316 measures the current induced in the HF antenna 311 by the magnetic field generated when the HF signal transmission / reception unit 314 is transmitting / receiving an HF band radio signal. The current measurement circuit 316 preferably measures the current induced in the HF antenna 311 while the dummy code is transmitted from the RF signal transmission unit 318. The dummy code is preferably data that is known between the in-vehicle device and the portable device 300. By making the dummy code known data between the in-vehicle device and the portable device 300, it is possible to prevent the data transmitted from the portable device 300 from being detected as erroneous data by the in-vehicle device. In addition, by transmitting the dummy code, it is possible to prevent inadvertent transmission of data transmitted to and from the in-vehicle device. The current measurement circuit 316 inputs a current measurement result to the portable device control unit 302.

  The portable device control unit 302 is connected to the LF signal receiving unit 310 and the short-range wireless communication unit 312. The portable device control unit 302 executes control of the entire portable device 300. The portable device control unit 302 performs a predetermined process based on the LF signal from the LF signal receiving unit 310. For example, the portable device control unit 302 creates a response signal in response to a request signal from the in-vehicle device. The portable device control unit 302 preferably creates a response signal accompanied by the ID code of the portable device 300. The portable device control unit 302 inputs a response signal to the RF signal transmission unit 318.

  The portable device control unit 302 includes an RF signal transmission condition setting unit 304, an HF reception signal determination unit 306, and a memory 308.

  The HF reception signal determination unit 306 determines whether or not wireless communication using the short-range wireless communication technology is being performed between the portable device 300 and the portable terminal 200. The HF reception signal determination unit 306 determines whether or not wireless communication using the short-range wireless communication technology is being performed between the portable device 300 and the portable terminal 200 based on the signal input from the HF signal transmission / reception unit 314. You may make it do. When the HF reception signal determination unit 306 determines that wireless communication using the short-range wireless communication technology is being performed with the portable terminal 200, the portable device control unit 302 holds the status state. When the portable device control unit 302 holds the status state, the portable device control unit 302 preferably performs control so as to transmit a dummy code from the RF signal transmission unit 318.

  In addition, the HF reception signal determination unit 306 notifies the RF signal transmission condition setting unit 304 that the status state is maintained. The RF signal transmission condition setting unit 304 sets the RF signal transmission condition in the RF signal transmission unit 318 when notified of holding the status state.

  The memory 308 stores a database in which a current value induced in the HF antenna 311 is associated with an RF signal transmission condition setting value. The RF signal transmission condition setting value is preferably a Q dump resistance value.

  The Q dump resistance value is an electric resistance for attenuating noise by suppressing the sharpness (Q) of resonance of the LC resonance circuit. By controlling the Q dump resistance value, the bandwidth, transient characteristics, phase characteristics, and the like of the RF signal transmission unit 318 can be improved. The resistance value of the Q dump resistor is preferably about several tens of ohms. The Q dump resistor is preferably connected in parallel with the resonant circuit.

  Based on the determination result from the HF reception signal determination unit 306, the RF signal transmission condition setting unit 304 transmits an RF signal when wireless communication is being performed with the mobile terminal 200 using the short-range wireless communication technology. Set conditions.

  The RF signal transmission condition setting unit 304 refers to the database stored in the memory 308 and specifies the RF signal transmission condition setting value associated with the current value measured by the current measurement circuit 316. The RF signal transmission condition setting unit 304 sets an RF signal transmission condition in the RF signal transmission unit 318.

  The RF signal transmission unit 318 is connected to the portable device control unit 302. The RF signal transmission unit 318 transmits an RF signal from the RF antenna 319 according to control by the portable device control unit 302. The RF signal transmission unit 318 wirelessly transmits a response signal from the portable device control unit 302. The RF signal transmission unit 318 preferably transmits a dummy code when the portable device control unit 302 holds the status state.

  The RF signal transmission unit 318 includes a power amplifier 320 and a Q dump setting unit 322.

  The power amplifier 320 controls the transmission power of the RF signal from the RF signal transmission unit 318.

  The Q dump setting unit 322 sets the RF signal transmission condition from the RF signal transmission condition setting unit 304. For example, a plurality of Q dump resistors and switches may be connected in parallel with the resonance circuit. In this case, the Q dump setting unit 322 may turn on one corresponding to the RF signal transmission condition from a plurality of switches.

<Antenna configuration of portable device 300>
FIG. 4 shows an embodiment of the antenna configuration of the portable device 300.

  In an embodiment of the antenna configuration of the portable device 300, both the RF antenna 319 and the HF antenna 311 are loop antennas, and both are arranged adjacent to each other. In FIG. 4, the LF antenna 309 is omitted.

  When an RF signal is transmitted from the RF antenna 319, a magnetic field is generated in the front direction from the back of the page. A current (described as “HF antenna current” in FIG. 4) is induced in the HF antenna 311 by the magnetic field. The current induced in the HF antenna 311 is measured by the current measurement circuit 316 of the short-range wireless communication unit 312.

<Operation of communication system>
FIG. 5 shows an embodiment of the operation of the communication system. FIG. 5 mainly shows the operation of the portable device 300.

  In step S502, the portable device 300 determines whether or not communication with the portable terminal 200 is being performed using the short-range wireless communication technology. The HF reception signal determination unit 306 preferably determines whether or not communication is being performed by the short-range wireless communication technology based on the input signal from the HF signal transmission / reception unit 314. If it is determined that communication is not being performed using the short-range wireless communication technology, the process returns to step S502.

  In step S504, when the portable device 300 determines that communication is being performed using the short-range wireless communication technology, the portable device 300 transmits a dummy code. If the portable device control unit 302 determines that communication is being performed using the short-range wireless communication technology, the portable device control unit 302 holds the status state. The RF signal transmission unit 318 is preferably controlled to transmit a dummy code when the portable device control unit 302 holds the status state.

  In step S506, the portable device 300 measures the current induced in the HF antenna. The current measurement circuit 316 measures the current induced in the HF antenna 311 by the magnetic field generated when the HF signal transmission / reception unit 314 is transmitting / receiving an HF band radio signal.

  In step S508, the portable device 300 sets the RF signal transmission condition based on the current induced in the HF antenna 311. The RF signal transmission condition setting unit 304 refers to the database stored in the memory 308 and extracts the RF signal transmission condition setting value associated with the current value measured by the current measurement circuit 316. The RF signal transmission condition setting unit 304 sets an RF signal transmission condition in the RF signal transmission unit 318.

  FIG. 6 shows an example of the relationship between the resonance frequency and the intensity of the output RF signal in the portable device 300. FIG. 6 shows initial circuit characteristics, that is, characteristics when no RF signal transmission conditions are set. FIG. 6 shows the characteristics after the transmission power control by the power amplifier 320 based on the current value induced in the HF antenna 311 and the Q dump is adjusted by the Q dump setting unit 322.

  In the initial circuit characteristics, when the portable device 300 is held over the portable terminal 200, the output intensity is reduced due to a shift in the resonance frequency. When the RF antenna 319 of the portable device 300 is close to a human body or a metal object, a matching shift of the antenna resonance circuit occurs, and an intended RF signal transmission output cannot be obtained.

  In one embodiment of the portable device 300, the measurement result of the current induced in the HF antenna 311 is fed back, and the transmission power and the Q value are adjusted based on the measurement result of the current. The current flowing through the antenna 319 is increased. For this reason, even when the portable device 300 is held over the portable terminal 200, the influence of attenuation of the output of the RF signal is reduced. Therefore, even when the resonance frequency is deviated, output attenuation is minimized.

  In one embodiment of the portable device 300, the transmission power and the Q value are adjusted based on the measurement result of the current induced in the HF antenna 311. One of the transmission power and the Q value may be adjusted based on the measurement result of the current induced in the HF antenna 311.

  In one embodiment of the portable device 300, the current induced in the HF antenna 311 is measured, but is not limited to the current induced in the HF antenna 311. For example, the degree of output of the RF signal may be detected based on other than the current induced in the HF antenna 311 such as the gain of the RF antenna 319. The transmission condition may be set based on a current other than the current induced in the HF antenna 311 such as the gain of the RF antenna 319.

  According to one embodiment of the communication system, the Q value is adjusted based on the current induced in the HF antenna by the transmission of the RF signal. By adjusting the Q value, it is possible to reduce the attenuation of the output of the RF signal due to external influences such as the influence of metal objects of the mobile terminal.

  When the current value and the Q value are associated with each other in the database stored in the memory, the output value can be prevented from increasing more than necessary by making the current value finer. Since the output can be prevented from rising more than necessary, the power consumption of the portable device can be reduced.

  Although the present invention has been described above with reference to specific embodiments and modifications, each embodiment and modification is merely illustrative, and those skilled in the art will recognize various modifications, modifications, alternatives, and substitutions. You will understand examples. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be implemented in hardware, software, or a combination thereof. The present invention is not limited to the above-described embodiments, and various variations, modifications, alternatives, substitutions, and the like are included without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle 200 Portable terminal 202 Short range wireless communication part 300 Portable machine 302 Portable machine control part 304 RF signal transmission condition setting part 306 HF reception signal determination part 308 Memory 309 LF antenna 310 LF signal reception part 312 Short distance wireless communication part 314 HF Signal transmission / reception unit 316 Current measurement circuit 318 RF signal transmission unit 320 Power amplifier 322 Q dump setting unit

Claims (7)

A communication control device included in a portable device capable of short-range wireless communication with a portable terminal,
An RF signal transmitter for transmitting an RF signal;
The portable device and the said short-range wireless communication with the portable terminal is executed, and when the transmission of the RF signal is performed, a current measurement for measuring a current generated in the short-range wireless communication antenna Circuit,
Based on the measurement results of the current by said current measuring circuit, and a control unit for controlling the output intensity of the RF signal,
Communication control device. Has a string attached databases and transmission conditions of current and the RF signal generated in the short-range wireless communication antenna,
The control unit, from the database, extracts the transmission condition of the RF signal that is linked to the measurement results of the current by the current measuring circuit, set on the RF signal transmitting unit that transmits the RF signal,
The communication control apparatus according to claim 1. It said transmission condition of the RF signal include at least one of transmit power and Q damping resistance,
The communication control apparatus according to claim 2. Wherein, when said portable unit and the short-range wireless communication with the portable terminal is executed, executes control Ru to send a dummy code to said RF signal transmitting unit that transmits the RF signal To
The communication control apparatus according to any one of claims 1 to 3. The current measurement circuit, while the dummy code is transmitted from the RF signal transmitting unit, to perform measurements of current,
The communication control apparatus according to claim 4. An RF signal transmitter for transmitting an RF signal;
A near field communication unit that performs near field communication;
A current measuring circuit that measures a current generated in the antenna of the short-range wireless communication when the short-range wireless communication and transmission of the RF signal are being executed;
Based on the measurement results of the current by said current measuring circuit, and a control unit for controlling the output intensity of the RF signal by the RF signal transmitting unit,
Portable machine. A communication control method executed by a communication control device included in a portable device capable of performing short-range wireless communication with a portable terminal,
An RF signal transmission step of transmitting an RF signal;
The portable device and the said short-range wireless communication with the portable terminal is executed, and when the transmission of the RF signal is performed, a current measurement for measuring a current generated in the short-range wireless communication antenna Steps ,
A control step of controlling the output intensity of the RF signal based on the measurement result in the current measurement step ,
Communication control method.

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