JP4301279B2 - Wireless device - Google Patents

Description

  The present invention relates to wireless communication, and more particularly to a wireless device that controls and shapes a communication range.

  FIG. 12 is a diagram illustrating a conventional wireless device. In the figure, 1 is a host controller, 2 is a wireless module, 3 is a baseband controller, 4 is an edgeless interface, 5 is a power amplifier, 6 is a low noise input amplifier, 7 is a switch, 9 is an antenna and an inverted F antenna.

  In this figure, the host controller 1 transfers data to the baseband controller 3. The baseband controller 3 modulates the transferred data. The modulated electrical signal is amplified by the output amplifier 5 and radiated as a radio wave from the antenna 9 to the space via the switch 7. On the other hand, the radio wave propagating in the space is received by the antenna 9 and amplified by the low noise input amplifier 6 via the switch 7. Thereafter, the amplified electrical signal is demodulated into data by the baseband controller 3 and transferred to the host controller 1.

  In the conventional wireless device, since the output of the power amplifier 5 and the input sensitivity of the low noise input amplifier 6 are fixed, the radio wave reachable range and audible range of the wireless device are also fixed. Therefore, for example, when a user of a wireless device having a reachable range and an audible range of 10 m communicates with another wireless device having equivalent performance, the user (or the wireless device itself) is centered on the user. It was possible to determine whether there was another wireless device within a radius of 10 m.

  However, the user of the wireless device cannot determine whether another wireless device exists in the vicinity of the user within the radius of 10 m. In other words, it has not been possible to identify who the other wireless device is in the vicinity of the user's own wireless device. In addition, the user of the wireless device cannot confirm whether another wireless device is approaching or moving away from the user himself / herself.

  On the other hand, there is a wireless device in which the output of the power amplifier 5 is variable. However, in this wireless device, the ratio between the output and the input sensitivity changes, and the reachable range of the radio wave depending on the output and the audible range of the radio wave depending on the input sensitivity are not the same size.

  For example, when a wireless device that is a base station at a certain point increases its output, the electric field strength around the base station increases and the reachable range is widened. Therefore, the radio waves of the base station are audible by the wireless device within the extended reach. In this state, if there is a call from the base station to the surrounding wireless device, the surrounding wireless device tries to respond to the base station, but the output of the surrounding wireless device remains low, so a link with the base station cannot be established. In addition, the peripheral wireless devices have a problem that the original communication cannot be performed only by repeating the response.

  In addition, when a wireless device that is a mobile station at a certain point in time decreases its output, the electric field strength around the mobile station decreases and the reach of radio waves narrows. Accordingly, radio waves do not reach radio apparatuses around the mobile station except for radio apparatuses in the vicinity of the mobile station. In this state, when called from a wireless device that is not near the mobile station, the mobile station's audible range remains the same, so the mobile station attempts to respond to the calling wireless device. However, since the output of the mobile station is low, radio waves do not reach the calling wireless device, communication with the wireless device is interrupted, and a new link cannot be established. Not only that, the mobile station simply repeats the response, and there is a problem that the original communication cannot be performed.

  Furthermore, in an environment in which a plurality of mobile stations generate a queue for a wireless device that is a base station, for example, a vending machine (base station) that provides services based on a request from a wireless device (mobile station), It was impossible to identify the first queue in the queue, that is, the wireless device that is the partner to be serviced first, or to distinguish the order of the wireless devices registered as the queue.

  The object of the present invention is to dynamically change without changing the ratio between the audible range and the reachable range of the wireless device, so that the identification of the communication partner, in particular whether another wireless device is approaching or moving away. It is easy to identify.

  In order to achieve the above object, according to the present invention, in a wireless device, a device for changing the intensity of each input / output signal, specifically an attenuator, is inserted between an antenna and a wireless module. By controlling, it has means for raising and lowering the output and input sensitivity in cooperation.

  According to a preferred aspect of the present invention, when the radius is switched between 2 m and 1 m using the set value of the attenuator, the distance relationship between the wireless device and the wireless device capable of communicating with the radius of 1 m and the wireless device capable of communicating with the radius of 2 m, In particular, the order of wireless devices registered in the queue and the wireless device in the front row are specified.

  In a different aspect of the present invention, the wireless device switches between an antenna and an antenna with an attenuator by means of a switch so that the radio wave reachable range and audible range are enlarged and reduced while maintaining the balance between the radio wave reachable range and the audible range. Do.

  In another aspect of the present invention, the wireless device establishes a link with another wireless device, for example, at 10 m, and then switches the antenna so that the radio wave reachable range and audible range are between 10 m and 1 m. Continue communication while alternately scaling up and down. As a result, the wireless device determines whether another wireless device has approached or moved away from the vicinity of 1 m.

  Furthermore, in another aspect of the present invention, for example, after establishing a link with one of a plurality of other wireless devices in a range of 10 m, the radio wave reachable range and the audible range are alternately expanded between 10 m and 1 m. The communication is continued while performing reduction, and another wireless device that has reached the vicinity of 1 m is specified.

  FIG. 1 is a diagram showing an embodiment of a radio apparatus to which the present invention is applied.

  In FIG. 1, 1 is a host controller, 2 is a wireless module, 3 is a baseband controller, 4 is a wireless interface, 5 is a power amplifier, 6 is a low noise input amplifier, 7 and 8 are switches, 91 and 92 are inverse Fs. The antenna 10 is an attenuator.

  The host controller 1 transfers data to the baseband controller 3. The transferred data is modulated by the baseband controller 3, amplified by the output amplifier 5, and reaches the switch 8 outside the wireless module 2 via the switch 7. An antenna 92 is connected to the switch 8 via an antenna 91 and an attenuator 10. When outputting the data that has reached the switch 8 via the antenna, the baseband controller 3 controls the switch 8 to select one of the antennas 91 and 92. Then, radio waves are radiated from the antenna selected by the switch 8 into the space.

  Note that the antennas 91 and 92 may be only one antenna 92 and the switch 8 may be used to select whether to drive the attenuator 10. In this configuration, the number of antennas can be reduced to produce the same effect as the present invention.

  On the other hand, the radio waves propagated through the space are received by the antennas 91 and 92. The received radio wave (data) is input from the antenna 91 to the switch 8 via the switch 8 and from the antenna 92 via the attenuator 10. The baseband controller 3 controls the switch 8 so that any one of the data input to the switch 8 is selected. The selected data is input to the wireless module 2. Data input to the wireless module 2 is amplified by the low noise input amplifier 6 and demodulated by the baseband controller 3. The demodulated data is transferred to the host controller 1.

  FIG. 2 is a diagram showing a radio wave reachable range of the wireless device of FIG. 11a indicates the reach of radio waves at 0 dBm output, and 11b indicates the reach of radio waves at -20 dBm output. In this aspect, the output of each antenna is set so that the electric field strength is the same at the position of the reachable range 11 a when output by the antenna 91 and the position of the reachable range 11 b when output by the antenna 92.

  FIG. 3 is a diagram showing an audible range of radio waves of the wireless device of FIG. 12a indicates an audible range at an input sensitivity of −72 dBm, and 12b indicates an audible range at an input sensitivity of −52 dBm. In this aspect, by switching the switch 8, the transmission source of the same output is within the audible range 11a when using the data received by the antenna 91 and within the audible range 11b when using the data received by the antenna 92. It is possible to receive radio waves output from the.

  FIG. 4 is a diagram showing establishment of a link of a wireless device to which the present invention is applied. In the figure, 13 is a wireless device to which the present invention is applied, 14a and 14b are conventional wireless devices, 15a is a radio wave reachable range and audible range of the radio device 13, and 16 is a radio wave reachable range and audible range of the radio device 14a. Show.

  By switching the switch 8, the wireless device 13 transmits and receives radio waves with a 10 dBm output and an input sensitivity of −72 dBm that do not pass through the attenuator 10. At this time, the radio device 13 has a radio wave reachable range and an audible range, that is, a radius of 15a is 10 m.

  The radio device 14a transmits and receives radio waves with a 10 dBm output and an input sensitivity of −72 dBm. The radio device 14 a has a radio wave reachable range and audible range, that is, a radius of 16 is 10 m, which is the same as the radio device 13.

  In FIG. 4, the wireless device 13 is inside the radio wave reachable range 16 of the radio device 14a, and the radio device 14a is inside the radio wave reachable range 15a of the wireless device 13. That is, the electric field strength at the position of each wireless device is at a level at which the outputs of each other can be received. Therefore, since all the wireless devices are within a distance where they can call each other, a link can be established.

  FIG. 5 is a diagram showing a case where the wireless device 13 switches between the radio wave reachable range and the audible range in FIG. In the figure, reference numeral 15b denotes a radio wave reachable range and an audible range of the wireless device 13 when radio waves are transmitted and received using the antenna 92 via the attenuator 10. In this case, the radius of 15b is 1 m.

  FIG. 5 shows a state in which the wireless device 14a that is linked to the wireless device 13 in FIG. 4 is approaching the vicinity of the wireless device 13. In this case, the radio device 14a can receive the radio wave output from the radio device 13 only within the circle of the radio wave reachable range and audible range of the radio device 13 indicated by 15b.

  Further, although the output of the wireless device 14a remains high, the output sensitivity of the wireless device 13 is decreased by -20 dBm due to the attenuator 10. That is, the audible range is narrowed to 15b. Therefore, the wireless device 13 can receive the radio wave output from the wireless device 14a only after the wireless device 14a enters the circle 15b. That is, the wireless device 13 can communicate with each other only with the wireless device 14a approaching the wireless device 13 by reducing the radio wave reachable range and the audible range while maintaining the mutual ratio.

  Furthermore, in FIG. 5, it is assumed that the wireless devices 14b are arranged in order behind the wireless device 14a. In this case, the wireless device 13 detects the presence of the wireless device 14a and the wireless device 14b using the radio wave reachable range and the audible range 15a. After detecting the presence of these wireless devices, if the wireless device 13 switches the antenna and the radio wave reachable range and audible range is 15b, the wireless device with which the wireless device 13 can communicate is only 14a approaching the wireless device 13. It becomes. In this case, the wireless device 13 confirms the difference between the wireless devices that can communicate, that is, the presence or absence of the wireless device before and after the change of the reachable range and the audible range of the radio wave, thereby changing the wireless device 13 to the wireless devices 14a and 14b. It can be specified that the wireless devices are arranged in the order. Furthermore, it can be specified that the wireless device 14a is a wireless device that exists in the vicinity of the wireless device 13.

As described with reference to FIGS. 4 and 5, the wireless device 13 includes means for switching between the radio wave reachable range and the audible range, so that the radio device 13 establishes a link between the radio wave reachable range and the audible range 15b. It is possible to specify whether the completed wireless device 14a is approaching or moving away from the wireless device 13 when the link can be established.
When there are a plurality of wireless devices, the wireless device 13 can specify the positions of the plurality of wireless devices. In this case, the wireless device whose position is specified may be a conventional wireless device whose radio wave reachable range and audible range are constant or about 10 m.

  FIG. 6 is a diagram showing the timing of communication when the radio apparatus (radio apparatus 13) of the present invention switches the radio wave reachable range and audible range with a timer. In the figure, 1301, 1302, 1303, 1304, 1305 and 1306 are calls from the wireless device 13, 14c and 14d are conventional wireless devices, and 1401, 1402, 1403, 1404 and 1405 are responses from the wireless devices 14c and 14d. Indicates. In FIG. 6, the vertical axis of the graph indicates the relative distance from the wireless device 13 to the wireless devices 14c and 14d.

  At time T0, the wireless device 13 outputs a call 1301 with an output of 0 dBm. The wireless device 14c that has received the call 1301 returns a response 1401 at time T1. Subsequently, the wireless device 13 outputs a call 1302 at time T2. The wireless device 14c that has received the call 1302 returns a response 1402 at time T3.

  The wireless device 13 that has received the response 1402 switches the output of the device to −20 dBm in accordance with a built-in timer in anticipation of a lapse of a predetermined time. In FIG. 6, the wireless device 13 switches the output so that the switching of the output is completed at time T5. The wireless device 13 outputs a call 1303 at time T6. However, in this figure, since the wireless device 14c is not within the radio wave reach of the wireless device 13, the response from the wireless device 14c does not return to the wireless device 13. When there is no response, the wireless device 13 determines that the wireless device 14c is not approaching or does not exist in the vicinity of 1 m of the wireless device 13 at time T7.

  Subsequently, the wireless device 13 outputs a call 1304 again at time T8. At time T8, the wireless device 14c in the vicinity of 1 m from the wireless device 13 can receive the call 1304. The wireless device 14c that has received the call 1304 returns a response 1403 at time T9.

  Receiving the response 1403, the wireless device 13 recognizes that the wireless device 14c exists in the vicinity of 1 m from itself, and starts preparation for service provision. The wireless device 13 returns the output to 0 dBm while preparing the service.

  The wireless device 13 outputs a call 1305 with an output of 0 dBm at time T12. The wireless device 14d that has received the call 1305 returns a response 1404 at time T13. If the preparation for the service is completed during this time, the wireless device 13 switches its output to −20 dBm at time T14 and outputs a call 1306. The call 1306 is received by the wireless device 14c waiting for the start of service provision in the vicinity of the wireless device 13. The wireless device 14c that has received the call 1306 returns a response 1405 at time T15. Through this exchange, 14c receives a service.

  The wireless device 13 that has succeeded in calling the wireless device 14d with an output of 0 dBm switches the output of the device to −20 dBm after a certain period of time according to the timer as described above, and detects the approach of the called wireless device 14d. The wireless device 13 that has succeeded in detecting the approach starts preparation for service provision, as in the case of the wireless device 14c. At the same time, the wireless device 13 changes the output to 0 dBm and calls another wireless device until it is ready for service provision. When preparation for service provision is completed, the wireless device 13 switches the output to −20 dBm again. Then, the wireless device 14d that has been waiting in the vicinity is called to start providing the service. As described above, by using the timer, the approach of the wireless device is efficiently detected and the service is provided.

  FIG. 7 is a diagram showing the switching timing of radio wave reachable range and audible range and the timing of communication when the wireless device 13 has a radiation sensor as detection means for detecting other wireless devices. is there. In the figure, 1307, 1308, 1309, 1310, 1311 and 1312 indicate calls, 14e and 14f indicate wireless devices, and 1406, 1407, 1408, 1409 and 1410 indicate responses. The vertical axis indicates the relative distance between the wireless devices 14e and 14f and the wireless device 13.

  The wireless device 13 outputs a call 1307 at time T0 and a call 1308 at time T2 with an output of 0 dBm. The wireless device 14e that has received the call 1307 returns a response 1406 at time T1. The wireless device 14f that has received the call 1308 returns a response 1407 at time T3.

  The wireless device 13 that has confirmed the wireless device responding within the audible range of 10 m switches the output to −20 dBm. In this figure, output switching is completed at time T4. The wireless device 13 senses the approach of another wireless device by a radiation sensor included in the host controller 1. The wireless device 13 that has detected the approach of the wireless device 14e by the radiation sensor outputs a call 1309 at time T6. In this case, since it is assumed that the call 1309 is not addressed to the wireless device 14e, the wireless device 14e does not return a response to the wireless device 13. If there is no response, the wireless device 13 recognizes that the called wireless device is not approaching. Subsequently, the wireless device 13 outputs a call 1310 addressed to the wireless device 14e at time T8. The wireless device 14e that has received the call 1310 returns a response 1408 at time T9.

  The wireless device 13 that has received the response 1408 recognizes that the wireless device 14e exists in the vicinity of a radius of 1 m from itself, and can confirm the wireless device that has reached the vicinity of the wireless device.

  The wireless device 13 outputs a call 1311 at time T10, and starts providing services to the wireless device 14e, for example, sending electronic tickets, sending electronic money, and providing information. The provision of this service is completed when the wireless device 14e returns a response 1409 at time T11.

  Until the provision of service to the wireless device 14e is completed, the wireless device 13 does not sense the approach of wireless devices other than the wireless device 14e. Therefore, the wireless device 13 that has completed providing the service to the wireless device 14e returns the output to 0 dBm in order to provide the service to another wireless device. In this figure, the output switching is completed at time T12.

  The wireless device 13 outputs a call 1312 at time T14 in order to notify other wireless devices that the service can be provided. The wireless device 14f that has received the call 1312 returns a response 1410 at time T15. The call 1312 is a call for prompting the wireless device 14 f to approach the wireless device 13.

  The wireless device 13 that has successfully called the wireless device 14f with 0 dBm output starts preparation for service provision. In the meantime, the wireless device 13 continues to call another wireless device that has newly entered the audible range of the wireless device 13. When the radiation sensor detects that the wireless device has approached the vicinity of the wireless device 13, the wireless device 13 switches the output to −20 dBm and identifies the called wireless device. The wireless device 13 that has succeeded in identifying the wireless device provides the prepared service. The wireless device 13 that senses the approach of another wireless device during service provision continues to specify the wireless device and provide the service at an output of −20 dBm after the service provision.

  When the approach of another wireless device is not sensed during service provision, the wireless device 13 switches the output mode to 0 dBm again, calls another wireless device, and prompts the approach as necessary. Thereby, the radio | wireless apparatus 13 can control the approach of a some radio | wireless apparatus, and can provide a service to a some radio | wireless apparatus sequentially.

  FIG. 8 is a diagram showing a relationship between output and input sensitivity in the wireless device 13. In the figure, 130 is the input sensitivity of the wireless device 13, and 140 and 141 are the input sensitivities of the conventional wireless device.

  Generally, the input sensitivity of a wireless device is set in consideration of the noise level around the wireless device. Specifically, a noise margin of 50 dB is taken for the desired sensitivity. That is, the input sensitivity of the wireless device is defined by accumulating a noise margin of 50 dB on the surrounding electric field strength. The input sensitivity of the conventional wireless device is -72 dBm.

  In the figure, the output of the wireless device 14a located at 0 m is received in the conventional wireless device located at 10 m with the input sensitivity 140 taking into account a noise margin of 50 dB. That is, as long as the distance is 10 m between conventional wireless devices, the outputs of each other can be received.

  Next, communication between the conventional wireless device and the wireless device 13 will be described. When the wireless device 13 receives the output of the conventional wireless device, the distance at which the wireless device 13 with an input sensitivity of −52 dBm can secure a noise margin of 50 dB with respect to the output of the wireless device 14a located at 0 m in FIG. The distance that the wireless device 13 can receive the output of the wireless device 14 a is 1 m indicated by the position of the input sensitivity 130 of the wireless device 13.

  In contrast, when the output of the wireless device 13 is received by the conventional wireless device, the output of the wireless device 13 located at 0 m in the drawing is already attenuated by 20 dBm by the attenuator. Therefore, the distance at which the conventional wireless device having an input sensitivity of −72 dBm can ensure a noise margin of 50 dB, that is, the distance at which the conventional wireless device can receive the output of the wireless device 13 is indicated by the position of the input sensitivity 141 of the conventional wireless device. 1m.

  As described above, the wireless device to which the present invention is applied is not only compatible with the connection with the conventional wireless device by the output via the antenna 91, but also by switching to the antenna 92 in which the attenuator 10 is inserted. Compatibility for connection with a conventional wireless device is ensured even at a distance of 1 m.

Further, by dynamically switching the antenna 91 and the antenna 92 with a switch, for example, the radio wave reachable range and audible range can be dynamically switched between 10 m and 1 m.
FIG. 9 is a diagram showing a first modification of the radio apparatus to which the present invention is applied. In the figure, 10b is an attenuator, 101 is a splitter, and 102 is a balun or termination. Data output from the wireless module 2 is input to the attenuator 10b. Each time the data input to the attenuator 10b is branched by the splitter 101 in the attenuator 10b, the intensity is attenuated by half. The split data is output from one branch of the splitter 101 to the antenna 9. Data that reaches the other branch is terminated by a termination 102 attached to the end of the branch.

  In this modification, both the output and the input can be attenuated at the same ratio by the splitter 101, so that the range can be reduced while maintaining the balance between the radio wave reachable range and the audible range.

  FIG. 10 is a diagram showing a second modification of the radio apparatus to which the present invention is applied. In the figure, reference numeral 10c denotes an attenuator including a metal piece. In the second modification, the antenna 9 is wrapped by the attenuator 10c, so that the range can be reduced while maintaining the balance between the radio wave reachable range and the audible range.

  FIG. 11 is a diagram showing a third modification of the radio apparatus to which the present invention is applied. In the figure, 5a is a variable output power amplifier, and 17 is a mixer circuit. The mixer circuit 17 has a noise source 170.

  The final stage of the variable output power amplifier 5a has a plurality of power amplifiers. Therefore, the output of the variable output power amplifier 5a changes according to the number of power amplifiers whose switches are turned on. Each of the plurality of power amplifiers may have the same or different transistor sizes and areas. However, the output of the variable output power amplifier 5a increases in proportion to the area of the transistor of the power amplifier whose switch is turned on. Therefore, it is necessary to incorporate a plurality of power amplifiers so that the variable output power amplifier 5a can perform a desired output. The baseband controller 3 controls the number of power amplifiers that are turned on by the variable output power amplifier 5a. For example, the variable output power amplifier 5a realizes a reach of 10 m when all of the plurality of power amplifiers are ON, and achieves a reach of 1 m when the number of power amplifiers to be turned on is 1.

  Data received by the antenna 9 is input to the mixer circuit 17. The mixer circuit 17 mixes the input data and the noise generated by the noise source 170 and outputs the mixed data to the low noise input amplifier 6. By mixing noise, the input sensitivity of the low noise input amplifier 6 is lowered from −70 dBm to −50 dBm. The baseband controller 3 suppresses noise output by directly controlling the noise source 170.

  According to this modification, the radio interface 4 including the variable output power amplifier 5a and the mixer circuit 17 can reduce the range of the radio wave while maintaining the balance between the reachable range and the audible range. The baseband controller 3 can control the reach of radio waves by controlling the variable output power amplifier 5a. Furthermore, the baseband controller 3 can finely adjust the audible range by controlling the noise source 170.

  FIG. 13 is a diagram showing a fourth modification example of the radio apparatus to which the present invention is applied. In the figure, 18 is a printed circuit board, 181 is a flat metal conductor which is an inner ground layer of the printed circuit board 18, 182 is a flat metal conductor which is an inner power layer of the printed circuit board 18, and 93 and 94 are antennas. .

  In this figure, the wireless module 2, the switch 8, and the antennas 93 and 94 are mounted on the surface of the printed circuit board 18.

On the inner layer of the printed circuit board 18, a flat metal conductor 181 that is a ground layer and a flat metal conductor 182 that is a power supply layer are arranged from the side close to the wireless module 2. The flat metal conductors 181 and 182 supply power to the wireless module 2 and the switch 8.
The antenna 93 is disposed so as to overlap the flat metal conductors 181 and 182 when viewed from above the printed circuit board 18. When viewed from the top of the printed circuit board 18, the antenna 93 does not have a portion that does not overlap the flat metal conductors 181 and 182.

  In addition, the gap between the metal conductor close to the antenna 93 and the antenna 93 out of the flat metal conductor 181 and the flat metal conductor 182 is in the range of 0.1 mm to 2 mm. This gap is derived from the thickness of the insulator film inserted between the metal conductors, and this thickness realizes sufficient withstand voltage and parasitic capacitance. The printed circuit board 18 of this modification is produced by alternately stacking insulator films and metal conductors in a sandwich shape. The thickness of the printed circuit board 18 is limited to about 2 mm by an apparatus for manufacturing the board. However, if the above-described gap is secured, sufficient withstand voltage and parasitic capacitance can be realized even if the printed circuit board 18 is about 2 mm. Further, even a so-called build-up substrate in which a metal conductor and an insulator are laminated on an insulating film serving as a base can achieve equivalent performance if the gap is set to 0.1 mm to 2 mm.

  On the other hand, the antenna 94 is disposed so as not to overlap the flat metal conductors 181 and 182 when viewed from the top of the printed circuit board 18. When viewed from the top of the printed circuit board 18, the antenna 94 does not overlap with the flat metal conductors 181 and 182.

  Data output from the wireless module 2 is input to the antenna 93 or 94 via the switch 8. The switch 8 switches the circuit so as to be electrically connected to one of the antenna 93 and the antenna 94.

  Since a capacitance is parasitic between the antenna 93 and the flat metal conductors 181 and 182, the resonance frequency of the antenna 93 is lowered. Therefore, the SWR increases and the ratio of power radiation to the space of the antenna 93 decreases.

  Further, most of the magnetic flux component of the radio wave radiated from the antenna 93 is absorbed by the flat metal conductors 181 and 182. Therefore, when the antenna 93 radiates radio waves, the electric field strength near the wireless device is weaker than when the antenna 94 radiates radio waves.

  That is, due to the generation of parasitic capacitance and the absorption of magnetic flux, the power that the antenna 93 radiates into the space is smaller than the power that the antenna 94 radiates into the space. Also, the antenna gain at the time of input to the antenna 93 is smaller than that of the antenna 94.

  Therefore, in this modification, the switch 8 switches between the antenna 93 and the antenna 94, so that the radio wave reachable range and audible range can be dynamically switched, for example, 10 m and 1 m.

  FIG. 14 is a view showing a state in which a wireless device to which the present invention is applied is mounted on the backrest of a seat such as a train or an airplane. In this figure, 20 is the back of the backrest, 201 is a tray mounted on the back of the backrest, 202 is a latch for fixing the tray, 203 is a beam and hinge of the tray, 94t is a tray built-in antenna on the tray upper side, and 94b is a tray floor. It is an antenna with a built-in tray. This figure shows a state in which the tray 201 is fixed to the back surface 20 of the backrest of the front seat by a latch 202.

  The tray 201 includes the wireless module 2, the switch 8, the antenna 93, the tray upper surface side tray built-in antenna 94t, and the tray floor surface side tray built in antenna 94b.

  The tray upper surface side tray built-in antenna 94t and the tray floor surface side tray built in antenna 94b are antennas having an attenuation function. The tray upper surface side tray built-in antenna 94t has a radiation pattern that covers the vicinity of the tray upper surface, and the tray floor surface side tray built in antenna 94b has a radiation pattern that covers the vicinity of the tray floor surface side. The antenna 93 has a radiation pattern that covers both the upper surface and the floor surface of the tray.

  The wireless module 2 uses the antenna 93 at startup. After that, the wireless module 2 switches the antenna to be used to the tray floor surface side tray built-in antenna 94b or the tray upper surface side tray built in antenna 94t by using the switch 8 when starting the service to the user. When switching to these antennas, the wireless device built in the tray can communicate only with the vicinity of the tray, specifically, with the vicinity of the seated person using the tray. As a result, only the wireless device possessed by the user sitting in the seat can communicate with the wireless device built in the tray.

  The wireless module 2 detects the position of the tray 201 by detecting that the latch 202 is in the latch position or that the beam of the tray 201 and the hinge 203 are not in the bent position. Based on the detected information, the wireless module 2 selects and uses the tray floor surface side tray built-in antenna 94b when the tray 210 is stored, and the tray top surface side tray built-in antenna 94t when it is pulled out.

  FIG. 15 is a diagram showing a fifth modification example of the radio apparatus to which the present invention is applied. In this figure, 183 is a flat metal conductor in the inner layer of the printed circuit board 18, 19 is a switch, and 95 is an antenna. The switch 19 may be a relay circuit.

  The wireless module 2 and the antenna 95 are mounted on the surface of the printed circuit board 18. The switch 19 is mounted on the back surface of the printed circuit board 18.

  A flat metal conductor 181 and a flat metal conductor 182 are arranged on the inner layer of the printed circuit board from the side close to the wireless module 2. The flat metal conductors 181 and 182 supply power to the wireless module 2 and the switch 19.

  The antenna 95 is disposed so as to overlap the flat metal conductor 183 when viewed from above the printed circuit board 18. When viewed from the top of the printed circuit board 18, the antenna 94 does not have a portion that does not overlap the flat metal conductor 183.

  Further, the gap between the antenna 93 and the flat metal conductor 183 is in the range of 0.1 mm to 2 mm.

  Data output from the wireless module 2 is input to the antenna 95. The switch 19 controls the electrical connection between the flat metal conductor 181 and the flat metal conductor 183 of the ground layer by turning on and off.

  When the flat metal conductor 181 and the flat metal conductor 183 of the ground layer are electrically connected by the switch 19, a capacitance is parasitic between the antenna 95 and the flat metal conductor 183. This lowers the resonance frequency of the antenna 95 and increases the SWR. Therefore, the ratio of power radiation from the antenna 95 to the space decreases.

  In this case, most of the magnetic flux component of the radio wave radiated from the antenna 95 is absorbed by the flat metal conductor 183. Therefore, the electric field strength in the vicinity of the wireless device is reduced by about 50 dB in the 2.4 GHz band, and is reduced to about 1/250 compared to the case where the flat metal conductor 183 is not energized.

  Therefore, when the switch 19 electrically connects the flat metal conductor 181 and the flat metal conductor 183 of the ground layer, the power radiated to the space by the antenna 95 is reduced due to the absorption of parasitic capacitance and magnetic flux, and the antenna gain at the time of input is reduced. Becomes smaller.

  Conversely, when the connection between the flat metal conductor 181 and the flat metal conductor 183 in the ground layer is cut off by the switch 19, the effect of absorbing parasitic capacitance and magnetic flux does not occur. Therefore, the power radiated to the space by the antenna 95 does not change.

  That is, in this modification, the switch 19 is turned on and off, so that the radio wave reachable range and audible range of the wireless device can be dynamically switched to, for example, 10 m and 1 m.

  In this modification, the switch 19 is assumed to be a MOS transistor switch or an electromagnetic relay, but may be a switching regulator that can be switched on and off from the outside.

  The wireless device to which the present invention is applied can divide other wireless devices in the wireless network into wireless devices outside the audible range and wireless devices within the audible range by controlling and reducing the audible range of the device itself. it can. A wireless device to which the present invention is applied behaves as a hidden terminal for wireless devices outside the audible range. Being a hidden terminal will not respond to any wireless terminal outside the audible range, and will not receive any questions. In this way, a wireless device to which the present invention is applied can dynamically divide a wireless network for convenience.

  Further, when the audible range is reduced, the link between the wireless device that is outside the audible range and the wireless device to which the present invention is applied is interrupted. Therefore, it is possible to construct a wireless network that intentionally disconnects links with a plurality of wireless devices by using the wireless device to which the present invention is applied.

  As described above, the present invention is useful for dynamically changing the reachable range and audible range of radio waves in a wireless device. It is also useful for confirming the relative distance between wireless devices. Further, it is useful when services are exchanged more efficiently in a wireless network.

It is a figure which shows the radio | wireless apparatus to which this invention is applied. It is a figure which shows the reach | attainment range of the electromagnetic wave of the radio | wireless apparatus to which this invention is applied. It is a figure which shows the audible range of the electromagnetic wave of the radio | wireless apparatus of this invention. It is a figure which shows the link establishment of the radio | wireless apparatus of this invention. It is a figure which shows switching of the radio wave reachable range and audible range of the wireless device of the present invention. It is a figure which shows the outline | summary of the switch of the reachable range and audible range of a radio wave by a timer, and communication. It is a figure which shows the outline | summary of the switch of the reach | attainment of an electromagnetic wave based on a detection means, and the audible range, and communication. It is a figure which shows the relationship between the output of the radio | wireless apparatus of this invention, and input sensitivity. It is a figure which shows the 1st modification of the radio | wireless apparatus to which this invention is applied. It is a figure which shows the 2nd modification of the radio | wireless apparatus to which this invention is applied. It is a figure which shows the 3rd modification of the radio | wireless apparatus to which this invention is applied. It is a figure which shows the prior art. It is a figure which shows the 4th modification of the radio | wireless apparatus to which this invention is applied. It is a figure which shows the system which mounts this invention on the tray of a seat. It is a figure which shows the 5th modification of the radio | wireless apparatus to which invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Host controller, 2 ... Wireless module, 3 ... Baseband controller, 4 ... Wireless interface, 5 ... Power amplifier, 6 ... Low noise input amplifier, 7 and 8 ... Switch, 91 and 92 ... Reverse F antenna, 10 ... Attenuator .

Claims (6)

In a wireless device capable of providing services,
A controller,
A wireless module connected to the controller;
A first antenna connected to the wireless module;
A communication range narrower than the first antenna, and a second antenna connected to the wireless module;
The controller can switch between the first antenna and the second antenna;
Even when the controller can communicate with other devices via the second antenna, the controller switches from the second antenna to the first antenna until the provision of service is ready, and the provision of the service is ready. In this case, the wireless device switches from the first antenna to the second antenna and communicates with the other device via the second antenna to provide the service . The wireless device according to claim 1, wherein
When the controller detects a device other than the other device while providing the service to the other device, the controller completes providing the service to the other device, and then A wireless device that communicates with a device other than the other device via an antenna . The wireless device according to claim 1, wherein
When the controller does not detect a device other than the other device while providing the service to the other device, the controller completes providing the service to the other device, and then performs the second operation. A radio apparatus for switching from the first antenna to the first antenna . In wireless devices that can provide services,
A controller,
A wireless module connected to the controller;
An antenna,
An attenuator connected to the antenna,
The controller can switch the attenuator on / off,
Even if the controller turns on the attenuator and can communicate with other devices via the antenna, the controller switches off the attenuator until the provision of service is ready, and when the provision of the service is ready, A radio apparatus comprising: turning on the attenuator; turning on the attenuator; and communicating with the other devices via the antenna to provide the service . The wireless device according to claim 4, wherein
When the controller detects a device other than the other device while providing the service to the other device, the controller, after completing the provision of the service to the other device, A wireless device that is turned on and communicates with a device other than the other device via the antenna . The wireless device according to claim 4, wherein
If the controller does not detect a device other than the other device while providing the service to the other device, the controller completes providing the service to the other device, and then turns the attenuator on. A wireless device characterized by switching to OFF.

Images