JP2008103821A - Repeater for in-vehicle communication - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repeater for in-vehicle communication for further flexibly responding for communication to various kinds of vehicles having different cabin structures. <P>SOLUTION: The repeater 2 is installed in a conspicuous place, for example, on the ceiling in a cabin and when the repeater repeats communication between an on-board ECU 1 disposed on a front side in the cabin and a mobile phone 3 located on a rear side, a directivity control unit adjusts directivity of an antenna to communicate with the mobile phone 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an in-vehicle communication repeater that relays near field communication performed in a passenger compartment.

  When a vehicle occupant brings a mobile phone into the passenger compartment, the mobile phone is connected to a device disposed in the passenger compartment by using short-range wireless communication such as Bluetooth (registered trademark). Technologies for use in hands-free calling have been proposed. For example, in Patent Document 1, a Bluetooth communication unit having a wireless antenna that can be switched separately for each seat position is provided, and when searching for the position of a mobile phone, each directional antenna is switched in turn to the mobile phone. When the mobile phone is detected in the driver's seat, it is automatically set to hands-free call Such a technique is disclosed.

Further, Patent Document 2 has a configuration in which a repeater for relaying short-range wireless communication between a car navigation device installed near the front panel and a mobile communication terminal is arranged on the ceiling in a vehicle interior. It is disclosed.
JP-A-2005-354122 JP 2002-359565 A

  The technique disclosed in Patent Document 1 has no problem when the structure of the vehicle compartment to be applied is determined in advance. However, if the structure of the passenger compartment is different, such as a 4-theta or 6-theta, or a vehicle having a wider space such as a wagon or a bus, a directional antenna prepared in advance accordingly is used. There was a problem that it was necessary to change the arrangement and the like and lacked versatility.

  Also, the technology disclosed in Patent Document 2 seems to be able to solve the above problem at first glance. However, in Patent Document 2, the conventional in-vehicle antenna is arranged so that the gain in the direction outside the vehicle compartment is higher than that in the vehicle interior. Therefore, a relay antenna is built in the room lamp so as to be close to the ceiling of the automobile. The directional gain in the vehicle interior direction is improved by using the ceiling as a reflector.

  Thus, when the reflector is enlarged and the directivity gain is improved, it is considered that the directivity becomes sharper and is directed directly below the antenna installation position. In this case, it is difficult to improve the communication state in the vehicle compartment over a wide range. For example, communication may not be possible in the rear seat of a minivan. In other words, the antenna directivity is not changed from that of Patent Document 1 in that it is fixed in a state where it is first installed.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an in-vehicle communication repeater that can flexibly cope with various types of vehicles having different vehicle cabin structures and perform communication. There is to do.

According to the in-vehicle communication repeater according to claim 1, when relaying near field communication performed between the in-vehicle communication device arranged on the front side in the vehicle interior and the portable communication terminal located on the rear side. In addition, the terminal-side communication means can adjust the directivity of the antenna that performs communication with the mobile communication terminal. That is, if the in-vehicle communication repeater of the present invention is installed in a place with a good view in the vehicle compartment, it can be relayed so that short-range wireless communication between the in-vehicle communication device and the portable communication terminal can be performed satisfactorily.
And while the positional relationship between the vehicle-mounted communication device and the repeater arranged in the front side of the vehicle interior and the communication environment are relatively stable, the mobile communication terminal is located on the rear side of the vehicle interior. It is assumed that the position is often different from time to time. Accordingly, the terminal-side communication means adjusts the directivity of the antenna, so that communication with the mobile communication terminal can be performed well according to the communication environment at that time.

  According to the in-vehicle communication repeater of the second aspect, the in-vehicle communication means is configured so that the directivity of the antenna that performs communication with the in-vehicle communication device can also be adjusted. That is, even if the positional relationship between the in-vehicle communication device and the repeater is stable, it is assumed that the communication environment changes depending on, for example, the presence or absence of a passenger on the passenger seat side. Therefore, communication can be performed more satisfactorily by adjusting the directivity of the antenna for the in-vehicle communication means.

According to the in-vehicle communication repeater of the third aspect, since the communication means adjusts the directivity by displacing the antenna with the actuator, the directivity can be adjusted with a simple configuration.
According to the in-vehicle communication repeater according to claim 4, since the monitoring antenna for monitoring the maximum reception level by changing the directivity is provided separately from the communication means, it approaches the maximum reception level. Thus, the antenna directivity of the communication means can be adjusted.

According to the in-vehicle communication repeater of the fifth aspect, the directivity is adjusted by changing the amount of phase shift given to each of the phase shifters arranged according to the plurality of antenna elements constituting the antenna array. That is, by configuring a so-called phased array antenna, the directivity can be adjusted more precisely.
According to the repeater for in-vehicle communication according to claim 6, since a part of the plurality of antenna elements constituting the antenna array is used as a monitoring antenna for monitoring the maximum reception level, the monitoring antenna is separately provided. There is no need to receive, and the configuration can be simplified.

  According to the in-vehicle communication repeater according to claim 7, the phase shift amount of one of the two elements is fixed by the phase shifter using two of the plurality of antenna elements as a monitoring antenna. The maximum reception level is monitored by changing the phase shift amount of the other antenna element and comparing the reception levels of the two elements. Then, if the former phase shift amount is slightly changed and fixed, and the latter phase shift amount is changed and the maximum reception level is similarly monitored sequentially, one of the elements constituting the phased array antenna is obtained. Can be used to monitor the maximum reception level.

According to the in-vehicle communication repeater of the eighth aspect, the adjustment of the antenna directivity is executed when the communication is started. Therefore, the adjustment can be performed according to the environment immediately before the communication is started.
According to the in-vehicle communication repeater according to claim 9, adjustment of the directivity of the antenna is performed at any time during communication. Therefore, even when the environment changes during communication, the directivity is adjusted according to the environment. be able to.

  According to the in-vehicle communication repeater of claim 10, the directivity adjustment data and the maximum reception level data obtained by the communication means are stored in the memory at the end of communication, and stored in the memory at the start of the next communication. The adjustment data being read is read out and set in the communication means. Then, by comparing the reception level obtained by the communication means at that time with the maximum reception level stored in the memory, it is determined whether or not the antenna directivity is readjusted. When there is almost no change, the optimum directivity can be set immediately and good communication can be performed.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an in-vehicle communication system configured by arranging an in-vehicle communication repeater of the present invention in a vehicle interior. Fig.1 (a) is a vertical side view of a vehicle interior. The in-vehicle ECU (in-vehicle communication device) 1 is disposed on the front side (the left side in FIG. 1A) of the vehicle interior, for example, in the dashboard. A repeater (in-vehicle communication repeater) 2 is installed at a substantially central portion of the ceiling in the passenger compartment. Between the in-vehicle ECU 1 and a mobile phone (mobile communication terminal) 3 carried by a passenger on the rear seat side. To relay short-range wireless communication (for example, Bluetooth).

FIG. 1B schematically shows the internal configuration of the repeater 2. The repeater 2 has a vehicle-mounted antenna 4 for communicating with the vehicle-mounted ECU 1 arranged on the lower left side in the figure and a terminal-side antenna 5 for communicating with the mobile phone 3 arranged on the lower right side in the figure. is doing. Above these, there is a communication control unit 6 that controls communication performed via both antennas 4 and 5. These antennas 4 and 5 are composed of, for example, a rod antenna or a patch antenna.
FIG. 2 is a plan view of the interior of the vehicle. The repeater 2 receives the direct wave (a) or the reflected wave (b) of the radio wave transmitted by the in-vehicle ECU 1 and transmits the received wave to the rear mobile phone 3. To the side. Although not shown, the same applies to transmission in the opposite direction.

  FIG. 3 shows the internal configuration of the repeater 2 in more detail. The repeater 2 includes a communication control unit 6, directivity control units 7 and 8 (on-vehicle side, terminal-side communication means) on the in-vehicle ECU side and terminal side, and a reception level monitoring unit 9. The communication control unit 6 includes a CPU 10, a memory 11, and the like. The directivity control units 7 and 8 are configured by the antennas 4 and 5 and motors 12 and 13 for changing the directions of the respective antennas 4 and 5. Similarly, the reception level monitoring unit 9 includes a level monitoring antenna 14 and a motor 15.

  The CPU 10 drives the motors (actuators) 12, 13, and 15 to change the directions of the corresponding antennas 4, 5, and 14, and reads the reception levels of the antennas 4, 5, and 14 by A / D conversion. It is like that. Then, the CPU 10 always rotates the level monitoring antenna 14, detects the direction in which the reception level of the antenna 14 is maximum, and based on the direction, the direction of the vehicle-mounted ECU side and the terminal-side antennas 4 and 5 Also controls. The memory 11 is a non-volatile memory (for example, a flash memory) in which the CPU 10 writes and stores a reception level, various control parameters, and the like.

  As shown in FIG. 2, the signal received by the in-vehicle ECU side antenna 4 is transmitted to the terminal side antenna 5 side via the inside of the CPU 10, and conversely, the signal received by the terminal side antenna 5 is It is transmitted to the vehicle-mounted ECU side antenna 4 side. Although not shown in FIG. 1, the level monitoring antenna 14 is arranged at a position that is equidistant from the two antennas 4 and 5.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing the contents of control by the CPU 10 of the repeater 2. The CPU 10 is activated when, for example, the position of the ignition key of the vehicle becomes “ACC” so that the in-vehicle ECU 1 is likely to perform communication in the passenger compartment. Then, first, the directions of the in-vehicle ECU side antenna 4 and the terminal side antenna 5 are set based on the directivity control parameter stored at the end of the previous process from the memory 11, and the directivity is reproduced (step S1). (If the direction during the previous control is maintained, it can be left as it is.)
And the signal transmitted from the vehicle-mounted ECU 1 is received by the vehicle-mounted ECU-side antenna 4, the signal transmitted from the mobile phone 3 brought in by the vehicle occupant is received by the terminal-side antenna 5, and the reception level thereof is the previous time. It is determined whether or not the maximum reception level differs greatly (step S2). That is, the communication conditions differ depending on the state of the passenger compartment, the number of passengers, the position of the passengers, and the like.

  In step S2, if the compared reception levels are substantially the same ("NO"), communication is started as it is (step S3). That is, the repeater 2 relays between the in-vehicle ECU 1 and the mobile phone 3. When the communication is completed, the CPU 11 stores the maximum reception level, the directivity control parameter (adjustment data), and the like at that time in the memory 11 (step S4), and ends the process.

  On the other hand, if the compared reception levels are significantly different in step S2 ("YES"), the CPU 10 first drives the motor 12 of the directivity control unit 7 to change the direction of the in-vehicle ECU side antenna 4, and the reception level. Is searched for a direction close to the maximum reception level by the level monitoring antenna 14 (step S5). Then, the directivity of the vehicle-mounted ECU-side antenna 4 is set in the direction in which the reception level is maximized (step S6). Then, CPU10 performs the same control also about the terminal side antenna 5 in step S7, S8. With these controls, the optimum communication directivity is set according to the situation in the vehicle interior at that time. Then, steps S3 and S4 are executed.

  It is assumed that there is no portable communication terminal that the vehicle-mounted ECU 1 should communicate with in the vehicle compartment, but in that case, wait until the received radio wave from the terminal side is detected in step S2. Alternatively, if a state in which the received radio wave is not detected continues for a certain period of time, it may be determined that a timeout has occurred and the process may be terminated.

As described above, according to the present embodiment, the repeater 2 is oriented when relaying communication performed between the in-vehicle ECU 1 arranged on the front side in the vehicle interior and the mobile phone 3 located on the rear side. Since the control unit 8 adjusts the directivity of the antenna 5 that communicates with the mobile communication telephone 3, if the repeater 2 is installed in a place with good visibility such as a ceiling in the vehicle interior, the vehicle-mounted ECU 1 and the mobile telephone 3 can be relayed so that communication with 3 can be performed satisfactorily.
And while the positional relationship or communication environment between the in-vehicle ECU 1 and the repeater 2 arranged on the front side in the vehicle interior is relatively stable, the cellular phone 3 is located on the rear side in the vehicle interior. Since it is assumed that there are many cases where this is different from time to time, it is possible to satisfactorily perform communication with the mobile phone 3 according to the communication environment at that time.

  For example, even if the technique disclosed in Patent Document 2 uses a “repeater” as in the present invention, the directivity of the antenna for the repeater with respect to the vehicle interior remains the same as the initial setting. Because it does not change, it cannot cope with changes in the communication environment. Further, since there is only one repeater antenna, it is assumed that the received radio wave is merely reflected. On the other hand, according to the configuration of the present invention, it is possible to flexibly cope with changes in the communication environment, and therefore, communication in a vehicle cabin that is configured vertically, such as a minivan or a bus, is extremely good. It can be carried out.

  The repeater 2 also adjusts the directivity of the antenna 4 with which the directivity control unit 7 communicates with the in-vehicle ECU 1. That is, even if the positional relationship between the in-vehicle ECU 1 and the repeater 2 is stable, the communication environment is assumed to change depending on, for example, the presence or absence of a passenger on the passenger seat side. If the directivity is adjusted, communication can be performed more satisfactorily. Then, by displacing the antennas 4 and 5 by the motors 12 and 13, directivity can be adjusted with a simple configuration.

Furthermore, since the repeater 2 includes the antenna 14 for monitoring the maximum reception level, the directivities of the antennas 4 and 5 can be adjusted so as to approach the maximum reception level. Further, since the CPU 10 executes adjustment of the directivity of the antennas 4 and 5 when communication is started, it can be adjusted according to the environment immediately before starting communication.
In addition, the CPU 10 stores the directivity control parameter and the data of the maximum reception level in the memory 11 at the end of communication, and reads the adjustment data stored in the memory 11 at the start of the next communication to read the directivity control unit 7, It is set to 8, and the reception level obtained by the antennas 4 and 5 at that time is compared with the maximum reception level read from the memory 11, and it is determined whether or not the directivity of the antennas 4 and 5 is readjusted. Therefore, when the communication environment has hardly changed from the previous time, the optimum directivity can be set immediately and good communication can be performed.

(Second embodiment)
FIG. 5 shows a second embodiment of the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals and the description thereof will be omitted. FIG. 5 is a view corresponding to FIG. In the second embodiment, the in-vehicle side directivity control unit (in-vehicle side communication means) 21 includes a plurality of antenna elements (antenna arrays) 4 (1) to 4 (n), and the plurality of antennas 4 are phase-shifted. The phase shifter 22 is connected to the CPU 24 via the adder / distributor 23.

The phase shifter 22 is controlled by the CPU 24 and individually adjusts the amount of phase shift of the plurality of antennas 4 (1) to 4 (n), and constitutes a so-called phased array antenna in combination with the plurality of antennas 4. is doing. That is, the directivity of the antenna 4 as a whole can be controlled by individually changing the phase shift amounts of the plurality of antennas 4.
The adder / distributor 23 is an interface between the phase shifter 22 and the CPU 24. The adder / distributor 23 adds and synthesizes the signals received by the plurality of antennas 4 and outputs the resultant signal to the CPU 24 side, and is output from the CPU 24 side. The signals are distributed corresponding to the plurality of antennas 4 and output to the phase shifter 22 side. Similarly, the terminal-side directivity control unit (terminal-side communication unit) 25 includes a plurality of antennas 5 (1) to 5 (n), a phase shifter 26, and an adder / distributor 27.

In addition, the directivity control unit 9 in the first embodiment is not provided, and instead, two of the plurality of antennas 4 and 5 function to monitor the maximum reception level. That is, the CPU 24 searches for the direction in which the maximum reception level is obtained by changing the phase shift amount of one of the above two while the phase shift amount is fixed, and then steps the former phase shift amount. The maximum reception level is detected by repeating the procedure of changing and fixing the latter and searching for the same direction by changing the latter phase shift amount. Other configurations are the same as those of the first embodiment.
In the above configuration, the adder / distributors 23 and 27, the CPU 24 and the memory 11 constitute the communication control unit 28, and the control units 21, 25 and 28 constitute the repeater (in-vehicle communication repeater) 29. ing.

  The directivity control process itself is executed according to the flowchart of FIG. In that case, when controlling the orientation in steps S1, S2, S5 to S8, etc., the CPU 24 gives the phase shift control command value to the phase shifters 22 and 26, thereby controlling the directivity of the antennas 4 and 5. In step S4, the phase shift control command value is stored as a control parameter.

  As described above, according to the second embodiment, the repeater 29 is arranged in accordance with the plurality of antennas 4 (1) to 4 (n) and 5 (1) to 5 (n) constituting the antenna array. Since the directivity is adjusted by changing the amount of phase shift given to each of the devices 22 and 26, the directivity can be adjusted more precisely by the phased array antenna. In addition, since a part of the plurality of antenna elements constituting the antenna array is used as a monitoring antenna for monitoring the maximum reception level, it is not necessary to receive a monitoring antenna separately, and the configuration can be simplified. it can.

  In that case, the CPU 24 changes the phase shift amount of the other antenna element while fixing the phase shift amount of one of the two elements, using two of the plurality of antenna elements as a level monitoring antenna, Since the maximum reception level is monitored by comparing the reception levels, the maximum reception level is monitored by using a part of the phased array antenna formed by combining the antenna arrays 4, 5 and the phase shifters 22, 26. It can be performed.

The present invention is not limited to the embodiments described above or shown in the drawings, and the following modifications are possible.
The adjustment of the antenna directivity may be executed at any time during communication. That is, steps S5 to S8 may be executed at any time during the execution of the communication started in step S3 of FIG. In this case, even when the environment in the passenger compartment changes during communication, the directivity can be adjusted according to the environment.
The storage process of the maximum reception level and control parameters in step S4 may be performed as necessary. Therefore, step S1 may be deleted, and the process may be started from step S2 every time it is activated.

The directivity adjustment may be performed after actually starting communication.
In the first embodiment, the reception level monitoring unit 9 may be deleted, and the directivity control units 7 and 8 may detect the respective maximum reception levels.
In the second embodiment, similarly to the first embodiment, the level monitoring antennas may be arranged independently.
A comparator that performs level comparison to obtain the maximum reception level may be configured by hardware such as a data register or a magnitude comparator.
The mobile communication terminal is not limited to the mobile phone 3 but may be a personal computer with a built-in communication module, a PDA (Personal Digital Assistants), or the like.

BRIEF DESCRIPTION OF THE DRAWINGS It is 1st Example of this invention, (a) is a schematic side view of the compartment which shows a communication system in a vehicle, (b) is a schematic side view which shows the structure of a repeater. Schematic plan view of the passenger compartment Functional block diagram showing detailed configuration of repeater Flowchart showing control contents by repeater CPU FIG. 3 equivalent view showing a second embodiment of the present invention.

Explanation of symbols

  In the drawings, 1 is an in-vehicle ECU (in-vehicle communication device), 2 is a repeater (in-vehicle communication repeater), 3 is a mobile phone (mobile communication terminal), and 4 (1) to 4 (n) are in-vehicle antennas (antenna arrays). ), 5 (1) to 5 (n) are terminal-side antennas (antenna arrays), 7 is an in-vehicle ECU-side directivity control unit (in-vehicle side communication means), and 8 is a terminal-side directivity control unit (terminal-side communication means). 12, 13 and 15 are motors (actuators), 14 is a level monitoring antenna, 21 is a vehicle-side directivity control unit (vehicle-side communication means), 22 and 26 are phase shifters, and 25 is a terminal-side directivity control unit. (Terminal side communication means) 29 constitutes a repeater (in-vehicle communication repeater).

Claims (10)

In an in-vehicle communication repeater for relaying short-range wireless communication performed between an in-vehicle communication device arranged on the front side in a vehicle interior and a mobile communication terminal located on the rear side,
Vehicle-side communication means for communicating with the vehicle-mounted communication device;
A terminal-side communication means for communicating with the mobile communication terminal,
The in-vehicle communication repeater, wherein the terminal-side communication means is configured to be able to adjust the directivity of an antenna that performs communication with the mobile communication terminal.   The in-vehicle communication repeater according to claim 1, wherein the in-vehicle communication unit is configured to be able to adjust the directivity of an antenna that performs communication with the in-vehicle communication device.   The in-vehicle communication repeater according to claim 1, wherein the antenna is displaced by an actuator to adjust directivity.   The in-vehicle communication repeater according to claim 3, further comprising a monitoring antenna for monitoring a maximum reception level by changing directivity separately from the communication means. The communication means includes
The antenna comprises an antenna array comprising a plurality of antenna elements;
A phase shifter that respectively shifts the phase of signals transmitted and received via the plurality of antenna elements;
The in-vehicle communication repeater according to claim 1 or 2, wherein the directivity is adjusted by changing the amount of phase shift given to each of the phase shifters.   6. The in-vehicle communication repeater according to claim 5, wherein the communication means uses a part of a plurality of antenna elements constituting the antenna array as a monitoring antenna for monitoring a maximum reception level. Two of the plurality of antenna elements are used as the monitoring antenna,
The phase shifter changes the phase shift amount of the other antenna element in a state where the phase shift amount of one of the two elements is fixed,
The in-vehicle communication repeater according to claim 6, wherein the maximum reception level is monitored by comparing the reception levels of the two elements.   The in-vehicle communication repeater according to any one of claims 1 to 7, wherein adjustment of the directivity of the antenna is performed when communication is started.   The in-vehicle communication repeater according to claim 1, wherein adjustment of the directivity of the antenna is performed at any time during communication. At the end of communication, the directivity adjustment data and the maximum reception level data obtained by the communication means are stored in a memory,
At the start of the next communication, the adjustment data stored in the memory is read and set in the communication means,
It is determined whether to re-adjust the antenna directivity by comparing the reception level obtained by the communication means at that time with the maximum reception level stored in the memory. The in-vehicle communication repeater according to any one of claims 1 to 9.

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