JP2005303903A - Wireless device, wireless communication system including the same, and wireless communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio apparatus capable of avoiding interference even in the case of not passing through a base station in communication between radio apparatuses equipped with an antenna capable of electrically switching directivity.
Radio devices 10 and 11 change radio beams from radio devices 12 to 15 other than the radio devices 11 and 10 that are communication partners to a plurality of beam patterns of antennas 20 and 21 during a standby period, respectively. Based on the plurality of received radio waves, a beam pattern when the radio wave having the maximum intensity is received is extracted. Then, the wireless device 10 performs wireless communication with the wireless device 11 using a beam pattern different from the beam pattern extracted during the standby period, and the wireless device 11 receives a signal from the wireless device 10 with the maximum intensity. Wireless communication is performed with the wireless device 10 using possible beam patterns.
[Selection] Figure 1

Description

  The present invention relates to a radio apparatus capable of avoiding interference in radio communication, a radio communication system including the same, and a radio communication method.

  Conventionally, in a wireless communication system that performs wireless communication between an access point (base station) and a large number of user terminals, communication interference has been avoided by the following method.

  In the uplink that performs communication from the user terminal to the access point, the access point has an array antenna, changes the directivity of the array antenna into a plurality of patterns, measures the signal strength from a large number of user terminals, A signal is transmitted to the user terminal having the best signal-to-noise ratio for each directivity (Non-Patent Document 1).

On the other hand, as an array antenna whose electric directivity can be switched, there is known an array antenna in which one feed element and six parasitic elements are arranged in a circle around the one feed element (non-feed) Patent Document 2). In this array antenna, six parasitic elements are loaded with varactor diodes that are variable capacitive elements, and the array antenna directivity is changed by changing the capacitances of the six varactor diodes loaded on the six parasitic elements. The sex is switched.
P. Viswanath, DN Tse, R. Laroria, “Opportunistic beamforming using dumb antennas”, IEEE trans. Inf. Theory, vol. 48, no. 6, pp. 1277-1294, June 2002. Hirata Akifumi, Tayu Fereddy, Aono Tomoyuki, Yamada Hiroki, Ohira Takashi, "Coherent two-wave direction-of-arrival experiment by reactance domain MUSIC method using ESPAR antenna", IEICE Tech. 59-64, May 2003.

  However, the method described in Non-Patent Document 1 is applied to a communication system in which a plurality of wireless devices communicate with each other at the same frequency without using a base station (access point), such as an ad hoc network. I can't. Therefore, in such a communication system, it is difficult to avoid interference. Therefore, when communication traffic increases, the communication system waits until communication of other stations is completed, resulting in a problem that the average communication speed decreases. A method of avoiding interference when performing wireless communication between a plurality of wireless devices equipped with an antenna that changes the directivity by changing the variable capacitance, that is, the loading reactance of the parasitic element as described above. Was not proposed.

  Therefore, the present invention has been made to solve such a problem, and the purpose thereof is in the case where a base station is not used in communication between wireless devices equipped with antennas capable of electrically switching directivity. However, it is to provide a wireless device that can avoid interference.

  Another object of the present invention is to provide wireless communication including a wireless device capable of avoiding interference even when not passing through a base station in communication between wireless devices equipped with antennas capable of electrically switching directivity. Is to provide a system.

  Furthermore, another object of the present invention is to provide a wireless communication method capable of avoiding interference even when not passing through a base station in communication between wireless devices equipped with antennas capable of electrically switching directivity. It is.

  According to the present invention, the wireless device is a wireless device that transmits a signal to a communication partner in accordance with a predetermined wireless communication protocol, and includes an antenna, a beam pattern switching unit, a beam pattern extraction unit, and a transmission unit. The antenna can electrically switch the beam pattern. The beam pattern switching means switches the beam pattern of the antenna to a plurality during the standby period. The beam pattern extraction means detects a radio wave having the maximum intensity from a plurality of radio waves received by the antenna when the beam pattern is switched to a plurality by the beam pattern switching means, and when the detected radio waves are received Extract the beam pattern. When transmitting the signal to the communication partner, the transmission unit sets a beam pattern different from the beam pattern extracted by the beam pattern extraction unit to the antenna and transmits the signal to the communication partner.

  Preferably, the beam pattern switching means holds a plurality of beam patterns, and switches the antenna beam patterns to a plurality according to the held beam patterns.

  Preferably, the transmission unit holds a map in which a plurality of intensities for a plurality of radio waves are associated with a plurality of beam patterns, and extracts a beam pattern different from the beam pattern from the beam pattern extraction unit with reference to the map. .

  Preferably, the antenna includes a feeding element and at least one parasitic element. At least one parasitic element is loaded with a variable capacitance element. The beam pattern switching means changes at least one capacitance of the variable capacitance element to switch the beam pattern of the antenna.

  According to the invention, the wireless communication system is a wireless communication system that transmits and receives signals according to a predetermined wireless communication protocol, and includes first and second wireless devices. The first radio apparatus receives radio waves from radio apparatuses other than the communication partner while switching the beam pattern to a plurality of during the standby period, and receives radio waves having the maximum intensity based on the received radio waves. The first beam pattern is detected, and at the time of signal transmission, a signal is transmitted using a second beam pattern different from the detected first beam pattern. The second radio apparatus receives radio waves from the first radio apparatus while switching the beam pattern to a plurality of beam patterns, and extracts a third beam pattern that minimizes interference based on the received radio waves, A signal is transmitted to the first radio apparatus using the extracted third beam pattern.

  Preferably, the first radio apparatus holds a plurality of beam patterns, and switches the beam patterns to a plurality according to the held beam patterns.

  Preferably, the first radio apparatus includes a first antenna that can electrically switch a beam pattern, a first beam pattern switching unit that switches a plurality of beam patterns of the first antenna during a standby period, When the first beam pattern switching means detects a radio wave having the maximum intensity from a plurality of radio waves received by the first antenna when the beam pattern is switched to a plurality of beam patterns, and when the detected radio wave is received A first beam pattern extracting means for extracting a first beam pattern, and a second beam pattern different from the first beam pattern extracted by the first beam pattern extracting means at the time of signal transmission from the first antenna; And a first transmission means for transmitting a signal. The second radio apparatus includes a second antenna that can electrically switch a beam pattern and a second beam that switches a plurality of beam patterns of the second antenna when receiving radio waves from the first radio apparatus. A third beam pattern that minimizes interference is extracted based on a plurality of radio waves received by the second antenna when a plurality of beam patterns are switched by the pattern switching unit and the second beam pattern switching unit. A second beam pattern extraction unit; and a second transmission unit configured to transmit a signal to the first radio apparatus using the third beam pattern extracted by the second beam pattern extraction unit.

  Further, according to the present invention, the wireless communication method is a wireless communication method for transmitting and receiving signals in accordance with a predetermined wireless communication protocol, wherein the transmitter switches the beam pattern to a plurality of beams during a standby period, and transmits to other than the communication partner. A first step of receiving a radio wave from a wireless device and detecting a first beam pattern when receiving a radio wave having a maximum intensity based on the plurality of received radio waves, and a transmitter to a communication partner A second step of transmitting a signal using a second beam pattern different from the first beam pattern detected in the first step, and the receiver transmits the radio wave from the transmitter to the beam pattern. A third step of extracting a third beam pattern that minimizes interference based on the plurality of received radio waves, and a receiver extracts And a fourth step of transmitting the signal to the transmitter using a third beam pattern.

  Preferably, in the first step, a plurality of beam patterns are switched according to a plurality of beam patterns preset in the transmitter. In the third step, a plurality of beam patterns are switched according to a plurality of beam patterns preset in the receiver.

  In the present invention, a wireless device that performs wireless communication detects a beam pattern that receives the strongest radio wave from a wireless device other than the communication partner during the standby period, and detects the beam pattern detected during the standby period during wireless communication. Wireless communication is performed using different beam patterns.

  Therefore, according to the present invention, radio communication can be performed while suppressing interference.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a conceptual diagram of a radio communication system according to an embodiment of the present invention. Referring to FIG. 1, a wireless communication system 100 according to an embodiment of the present invention includes wireless devices 10-15. The radio devices 10 to 15 are equipped with antennas 20 to 25, respectively. The wireless devices 10 to 15 are arranged in the wireless communication space 30 and perform wireless communication with each other while avoiding interference according to a method described later according to the IEEE 802.11 communication protocol. That is, the wireless communication system 100 constitutes an ad hoc network that performs wireless communication between a plurality of wireless devices.

  In the following, a case where the wireless device 10 performs wireless communication with the wireless device 11 will be described. Accordingly, the wireless devices 12 to 15 correspond to wireless devices other than the communication partner for the wireless devices 10 and 11.

  FIG. 2 is a functional block diagram showing an internal configuration of the wireless device 10 shown in FIG. 1 and a perspective view of the antenna 20 mounted on the wireless device 10. Referring to FIG. 2, antenna 20 includes antenna elements 1 to 7 and varactor diodes 1D to 6D. The antenna elements 1 to 7 are arranged on a predetermined plane along a predetermined direction. The radio apparatus 10 includes a beam pattern switching unit 40, a receiving unit 50, and a transmitting unit 60.

  FIG. 3 is a plan layout view of the antenna elements 1 to 7 shown in FIG. Referring to FIG. 3, antenna elements 1 to 7 are arranged in a circular CRC around antenna element 7. The distance between the antenna element 7 and each of the antenna elements 1 to 6 is set to λ / 4, for example, where λ is the wavelength of the radio wave transmitted and received by the antenna 20. Moreover, the antenna elements 1-6 are arrange | positioned at equal intervals.

  Referring to FIG. 2 again, the antenna element 7 is a feeding element, and the antenna elements 1 to 6 are parasitic elements. Varactor diodes 1D to 6D are connected between antenna elements 1 to 6 and the ground node, respectively. As a result, the varactor diodes 1D to 6D that are variable capacitance elements are loaded on the antenna elements 1 to 6 that are parasitic elements.

  As described above, the antenna 20 has seven antenna elements including one feeding element (antenna element 7) and six parasitic elements (antenna elements 1 to 6) in a circular shape centering on the feeding element. It consists of an arranged structure.

  The beam pattern switching means 40 supplies control voltages CVL1 to CVL6 to the varactor diodes 1D to 6D to switch the beam pattern of the antenna 20. The capacitances (reactance values) of the six varactor diodes 1D to 6D are changed by the control voltages CVL1 to CVL6, respectively. The beam pattern switching means 40 determines the voltage values of the control voltages CVL1 to CVL6 so that the reactance value in each varactor diode becomes “hi” (maximum value) or “lo” (minimum value), and the control voltages CVL1 to CVL1. CVL6 is supplied to six varactor diodes 1D to 6D.

In this case, the beam pattern switching unit 40 includes six varactor diode set _{x m} reactance values _x m1 _{~x m6} in 1D~6D of six control voltage CVL1~CVL6 to vary as shown in Table 1 Supply to varactor diodes 1D-6D.

FIG. 4 is a diagram showing a beam pattern of the antenna 20 shown in FIG. Referring to FIG. 4, when all of reactance values x _{m1 to} x _m6 are “hi” (m = 0), antenna 20 has a beam pattern BPM0 composed of an omni pattern having sensitivity in all directions. When the reactance value x _m1 is “lo” and the reactance values x _{m2 to} x _m6 are “hi” (m = 1), the antenna 20 uses a beam pattern BPM1 having directivity in the direction of 0 degrees. Have. The direction of 0 degrees is the direction of the line segment connecting the antenna element 1 and the antenna element 7 shown in FIG.

Further, when the reactance value x _m2 is “lo” and the reactance values x _m1 , x _{m3 to} x _m6 are “hi” (m = 2), the antenna 20 is a beam having directivity in the direction of 60 degrees. It has a pattern BPM2.

Similarly, when the reactance values x _{m3 to} x _m6 are “lo” and the other reactance values are “hi” (m = 3 to 6), the antenna 20 is 120 degrees and 180 degrees. Beam patterns BPM3 to BPM6 having directivity in directions of 240 degrees and 300 degrees.

Thus, the beam pattern switching means 40 changes the directivity of the antenna 20 by changing the reactance values x _{m1 to} x _m6 of the six varactor diodes 1D to 6D loaded on the antenna elements 1 to 6 which are parasitic elements. That is, the beam pattern of the antenna 20 is switched to beam patterns BPM0 to BPM6.

  Referring to FIG. 2 again, the beam pattern switching unit 40 holds the beam patterns BPM0 to BPM6 in advance, and the held beam pattern during a period when the wireless device 10 does not wirelessly communicate with the other wireless devices 11 to 15. According to BPM0 to BPM6, the beam pattern of the antenna 20 is sequentially switched to a beam pattern BPM0, a beam pattern BPM1,. In this case, when the radio apparatus 10 receives the signal STP indicating that the radio apparatus 10 does not perform radio communication with the other radio apparatuses 11 to 15, the beam pattern switching means 40 continues to switch the beam pattern of the antenna 20. In addition, when the wireless device 10 performs wireless communication with the wireless device 11 that is the communication partner, the beam pattern switching unit 40 receives the signal BDE from the receiving unit 50 and the beam pattern (beam patterns BPM1 to BPM1) designated by the signal BDE. The control voltages CVL1 to CVL6 are supplied to the varactor diodes 1D to 6D so as to generate any one of BPM6).

  The receiving means 50 is connected to the antenna element 7 that is a power feeding element of the antenna 20 and receives a reception signal RSS from the antenna element 7. The receiving means 50 receives the reception signals RSS0 to RSS6 from the antenna element 7 when the beam pattern of the antenna 20 is switched like the beam patterns BPM0 to BPM6. The receiving means 50 holds the beam patterns BPM0 to BPM6 of the antenna 20 shown in FIG.

  And the receiving means 50 detects the received signal (any one of the received signals RSS0 to RSS6) from the received signals RSS0 to RSS6, and extracts the beam pattern when the detected received signal is obtained. To do. In the present invention, the beam pattern switching means 40 switches the beam pattern of the antenna 20 in a predetermined order (beam pattern BPM0, beam pattern BPM1,... Beam pattern BPM6). The beam pattern when the maximum received signal is obtained can be easily extracted. For example, when the received signal RSS3 has the maximum intensity among the received signals RSS0 to RSS6, the receiving unit 50 extracts the beam pattern BPM3. And the receiving means 50 memorize | stores the extracted beam pattern.

  The operation in which the beam pattern switching means 40 sequentially switches the beam pattern of the antenna 20 to the beam pattern BPM0, beam pattern BPM1,... Beam pattern BPM6 is a period in which the wireless device 10 is not wirelessly communicating with the other wireless devices 11-15. That is, since it is continuously performed during the standby period of the wireless device 10, the reception unit 50 receives the reception signals RSS0 to RSS6 sequentially from the antenna element 7 during the standby period of the wireless device 10, and receives the received signal. Based on RSS0 to RSS6, the beam pattern when the received signal having the maximum intensity is obtained is extracted, and the extracted beam pattern is updated and stored.

  When receiving the signal CDIR for instructing the radio apparatus 10 to start communication with the radio apparatus 11, the receiving means 50 receives a signal BDE for designating a beam pattern different from the stored beam pattern. The generated signal BDE is output to the beam pattern switching means 40.

  In addition, when receiving the communication permission signal CTS from the wireless device 11 via the antenna 20, the receiving unit 50 generates a signal RCT indicating that the communication permission signal CTS has been received and outputs the signal RCT to the transmitting unit 60.

  Further, when receiving the communication request signal RTS from the wireless device 11 via the antenna 20, the receiving unit 50 generates a signal RRT indicating that the communication request signal RTS has been received and outputs the signal RRT to the transmitting unit 60.

  Further, when receiving the data Data from the wireless device 11 via the antenna 20, the receiving unit 50 generates a signal RDA indicating that the data Data has been received and outputs the signal RDA to the transmitting unit 60.

  The transmission means 60 is connected to the antenna element 7 which is a power feeding element of the antenna 20. When receiving the signal CDIR, the transmission means 60 generates a communication request signal RTS and supplies it to the antenna element 7 of the antenna 20. In addition, when the transmission unit 60 receives the signal RCT from the reception unit 50, the transmission unit 60 supplies the data Data to the antenna element 7. Further, when receiving the signal RRT from the receiving means 50, the transmitting means 60 generates a communication permission signal CTS and supplies it to the antenna element 7. Further, when receiving the signal RDA from the receiving means 50, the transmitting means 60 generates an acknowledgment ACK and supplies it to the antenna element 7.

  Each of the wireless devices 11 to 15 has the same configuration as the wireless device 10, and each of the antennas 21 to 25 has the same configuration as the antenna 20.

  FIG. 5 is a timing chart showing the operation timing of the wireless communication system 100 shown in FIG. Referring to FIG. 5, in wireless communication system 100, wireless device 12 is performing wireless communication with wireless device 13 before wireless device 10 starts wireless communication with wireless device 11, and wireless device 14 is wirelessly connected. A situation where wireless communication with the device 15 is performed is assumed.

  In this case, the wireless device 12 generates a communication request signal RTS at timing t1 and transmits it to the wireless device 13. Then, the wireless device 13 generates a communication permission signal CTS in response to the communication request signal RTS from the wireless device 12 and transmits the communication permission signal CTS to the wireless device 12. Then, the wireless device 12 generates and transmits data Data to the wireless device 13 according to the communication permission signal CTS from the wireless device 13, and the wireless device 13 receives the data Data from the wireless device 12. An acknowledgment ACK is generated and transmitted to the wireless device 12.

  After timing t3, the same wireless communication as the wireless communication between the wireless device 12 and the wireless device 13 described above is performed between the wireless device 14 and the wireless device 15.

  Thus, before the wireless device 10 starts wireless communication with the wireless device 11, wireless communication is performed between the other wireless devices. In such a situation, between timing t1 and timing t4, the wireless devices 10 and 11 are in an idle state, that is, in a standby state, and the communication request signal RTS transmitted by the wireless devices 12 and 14 and the wireless devices 13 and The communication permission signal CTS transmitted by 15 can be received.

  Therefore, in the present invention, the wireless devices 10 and 11 are switched from the wireless devices 12 to 15 other than the communication partner while sequentially switching the beam patterns of the antennas 20 and 21 to a plurality of times during the standby period from the timing t1 to the timing t4. Communication request signal RTS and communication permission signal CTS.

  More specifically, the wireless devices 10 and 11 sequentially switch the beam patterns of the antennas 20 and 21 to a beam pattern BPM0, a beam pattern BPM1,. 12 receives the communication request signal RTS from the wireless device 13, receives the communication permission signal CTS from the wireless device 13 at the timing t2, receives the communication request signal RTS from the wireless device 14 at the timing t3, and from the wireless device 15 at the timing t4. The communication permission signal CTS is received.

  In this case, the radio apparatuses 10 and 11 receive the communication request signal RTS or the communication permission signal CTS at four timings t1 to t4 while sequentially switching the beam patterns of the antennas 20 and 21 to the beam patterns BPM0 to BPM6, respectively. During the period, six reception signals RSS1 to RSS6 are repeatedly received. And every time the radio devices 10 and 11 receive the six reception signals RSS1 to RSS6, the radio devices 10 and 11 detect the reception signal having the maximum intensity from the six reception signals RSS1 to RSS6, and the detected reception signals are detected. The received beam pattern is extracted and stored.

  In this case, the wireless device 10 receives the communication request signal RTS from the wireless devices 12 and 14 with the highest intensity of the radio wave using the beam pattern BPM6, and receives the communication permission signal CTS from the wireless devices 13 and 15 as a beam. Assume that the pattern BPM5 is used to receive the radio wave with the highest intensity. The wireless device 11 receives the communication request signal RTS from the wireless devices 12 and 14 by using the beam pattern BPM5 with the highest intensity of the radio wave, and receives the communication permission signal CTS from the wireless devices 13 and 15 as the beam pattern. Assume that radio waves are received with the highest intensity using BPM4.

  As described above, the wireless devices 10 and 11 continuously measure the wireless communication between the other wireless devices 12 to 15 around the wireless devices 10 and 11 during the standby period.

  When performing wireless communication with the wireless device 11, the wireless device 10 sets a beam pattern on the antenna 20 that is different from the beam pattern that received the communication request signals RTS and the like from the wireless devices 12 to 15 during the standby period. The communication request signal RTS is transmitted to the wireless device 11 at t5.

  In this case, the radio apparatus 10 sets the beam pattern BPM1 to the antenna 20 and transmits a communication request signal RTS to the radio apparatus 11. As described above, the wireless device 10 receives the communication request signal RTS or the communication permission signal CTS from the wireless devices 12 to 15 using the beam pattern BPM5 or BPM6 with the highest radio wave intensity. , A beam pattern BPM1 different from BPM6 is set in the antenna 20, and a communication request signal RTS is transmitted to the wireless device 11.

  The wireless device 11 receives the communication request signal RTS from the wireless device 10 while sequentially switching the beam pattern of the antenna 21 to the beam pattern BPM0, beam pattern BPM1,..., Beam pattern BPM6, and the signal-to-interference ratio is The beam pattern that minimizes is extracted. Then, the wireless device 11 sets the extracted beam pattern in the antenna 21 and transmits a communication permission signal CTS to the wireless device 10 at timing t6.

  In this case, the wireless device 11 calculates six received signal strengths RSSI1_10 to RSSI6_10 when the communication request signal RTS from the wireless device 10 is received using the beam patterns BPM1 to BPM6, and the wireless device 12 during the standby period. The received signal strength RSSI_intf when the communication request signal RTS or the communication permission signal CTS from ˜15 is received using the beam pattern BPM5 or BPM6 is compared with the calculated received signal strength RSSI1_10 to RSSI6_10. Then, the radio apparatus 11 detects the radio wave intensity that maximizes the intensity ratio with respect to the received signal strength RSSI_intf from the six received signal strengths RSSI1_10 to RSSI6_10, and detects the detected received signal strength (any one of the received signal strengths RSSI1_10 to RSSI6_10). ) Is obtained.

  As described above, the wireless device 11 receives the communication request signal RTS or the communication permission signal CTS from the wireless devices 12 to 15 by using the beam pattern BPM4 or BPM5 with the highest strength of the received signal. The beam pattern having the maximum intensity ratio with respect to the intensity RSSI_intf, that is, the beam pattern having the minimum signal-to-interference ratio is, for example, the beam pattern BPM3. Therefore, the wireless device 11 sets the beam pattern BPM3 to the antenna 21 and transmits the communication permission signal CTS to the wireless device 10.

  Then, in response to receiving the communication permission signal CTS from the wireless device 11, the wireless device 10 transmits data Data to the wireless device 11 using the beam pattern BPM1. When the reception of the data Data from the wireless device 10 is completed, the wireless device 11 transmits an acknowledgment ACK to the wireless device 10 using the beam pattern BPM3.

  As described above, when the wireless devices 10 and 11 extract the beam pattern for receiving signals of the wireless devices 12 to 15 other than the communication partner during the standby period and perform wireless communication between the wireless devices 10 and 11. Wireless communication is performed using a beam pattern different from the extracted beam pattern.

  As a result, it is possible to perform wireless communication between the wireless devices 10 and 11 while minimizing interference from wireless communication performed between the wireless devices 12 to 15.

  FIG. 6 is a flowchart for explaining the operation when wireless communication is performed between the two wireless devices 10 and 11 shown in FIG. Referring to FIG. 6, when a series of operations is started, radio apparatus 10 changes the beam pattern of antenna 20 to beam pattern BPM1, beam pattern BPM2,..., Beam pattern BPM6 during the standby period. The radio waves from the wireless devices 12 to 15 other than the communication partner are received while sequentially switching (step S1).

  Then, the radio apparatus 10 extracts the beam pattern BPM_intf1 that has received the radio wave having the maximum intensity based on the received radio waves, and stores the extracted beam pattern BPM_intf1 (step S2).

  On the other hand, similarly to the wireless device 10, the wireless device 11 receives the radio wave from the wireless devices 12 to 15 while changing the beam pattern to a plurality of beam patterns during the standby period, and receives the radio wave having the maximum intensity. BPM_intf2 is extracted and stored (steps S3 and S4).

  Thereafter, the wireless device 10 determines whether there is an instruction for wireless communication with the wireless device 11 (step S5). More specifically, the wireless device 10 determines whether there is an instruction for wireless communication with the wireless device 11 based on whether the signal CDIR has been received. And when it determines with there having been no communication instruction | indication with the radio | wireless apparatus 11, step S1-S4 mentioned above is repeatedly performed.

  When it is determined in step S5 that there is an instruction for wireless communication with the wireless device 11, the wireless device 10 sets the beam pattern BPM_fvr1 different from the beam pattern BPM_intf1 extracted in step S2 to the antenna 20 and sets the communication request signal RTS. Is transmitted to the wireless device 11 (step S6).

  Then, the wireless device 11 receives the communication request signal RTS from the wireless device 10 while sequentially switching the beam pattern of the antenna 21 to the beam pattern BPM1, beam pattern BPM2,..., Beam pattern BPM6 (step S7). . Then, the wireless device 11 extracts the beam pattern BPM_fvr2 when the radio wave having the minimum interference is received based on the received radio waves by the method described above (step S8), and the extracted beam pattern BPM_fvr2 is the antenna. The communication permission signal CTS is set to 21 and transmitted to the wireless device 10 (step S9).

  After that, the wireless device 10 sets the beam pattern BPM_fvr1 to the antenna 20 and receives the communication permission signal CTS from the wireless device 11 (step S10), and receives the data Data as the beam pattern BPM_fvr1 in response to the reception of the communication permission signal CTS. Is transmitted to the wireless device 11 (step S11). Then, the radio apparatus 11 sets the beam pattern BPM_fvr2 to the antenna 21 and receives the data Data from the radio apparatus 10 (step S12). When the reception of the data Data is completed, the radio apparatus 11 sends an acknowledgment ACK using the beam pattern BPM_fvr2. It transmits to the radio | wireless apparatus 10 (step S13). The radio apparatus 10 receives the confirmation response ACK from the radio apparatus 11 using the beam pattern BPM_fvr1 (step S14), and the entire operation ends.

  As described above, the wireless devices 10 and 11 extract the beam pattern that receives the radio waves from the wireless devices 12 to 15 other than the communication partner with the maximum intensity during the standby period (see steps S1 to S4). , 11 are communicated with each other using a beam pattern different from the beam pattern extracted during the standby period (see steps S6 to S14). Therefore, it is possible to perform wireless communication with the communication partner while suppressing interference of radio waves transmitted from the wireless devices 12 to 15 other than the communication partner.

  The operations in the wireless devices 10 and 11 are actually executed by a CPU (Central Processing Unit). The CPU reads a program including each step of the flowchart shown in FIG. 6 from a ROM (Read Only Memory) and executes the program. In accordance with the steps shown in FIG.

  In the above description, the antennas 20 to 25 are described as including one feeding element (antenna element 7) and six parasitic elements (antenna elements 1 to 6). Not limited to this, the antennas 20 to 25 may be configured by one feeding element and at least one parasitic element.

  Moreover, when the radio | wireless apparatus 10 and 11 extracted the beam pattern which receives the electromagnetic wave from radio | wireless apparatuses 12-15 other than a communicating party with the maximum intensity | strength during a waiting period, it demonstrated that the extracted beam pattern was updated and memorize | stored, In the present invention, the present invention is not limited to this, and when a beam pattern having a radio field strength stronger than that when using a beam pattern that has already been updated and stored is extracted, the extracted beam pattern is updated and stored. Also good.

  Further, all the beam patterns extracted during the standby period by the wireless devices 10 and 11 are stored, and the beam pattern having the maximum radio wave intensity is extracted from all the stored beam patterns during wireless communication. May be.

  Further, the wireless devices 10 and 11 create and hold a map in which a plurality of radio wave intensities received from wireless devices other than the communication partner during the standby period are associated with a plurality of beam patterns, and at the time of communication with the communication partner, The beam pattern used for communication may be determined with reference to the held map.

  In the present invention, the wireless device 10 constitutes a “transmitter”, and the wireless device 11 constitutes a “receiver”.

  Further, in the radio apparatus 10, the receiving means 50 for extracting the beam pattern BPM_intf1 constitutes a “beam pattern extracting means” or a “first beam pattern extracting means”.

  Further, in the wireless device 11, the receiving means 50 for extracting the beam pattern BPM_intf2 constitutes a “second beam pattern extracting means”.

  Furthermore, in the radio apparatus 10, the receiving means 50 for extracting the beam pattern BPM_fvr1, the beam pattern switching means 40 for setting the beam pattern BPM_fvr1 in the antenna 20, and the transmitting means 60 for supplying the communication request signal RTS and the like to the antenna element 7 include: It constitutes “transmission means” or “first transmission means”.

  Further, in the wireless device 11, the receiving means 50 for extracting the beam pattern BPM_fvr2, the beam pattern switching means 40 for setting the beam pattern BPM_fvr2 in the antenna 21, and the transmitting means 60 for supplying the communication request signal RTS and the like to the antenna element 7 include: "Second transmission means" is configured.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a radio apparatus capable of avoiding interference even in the case of not passing through a base station in communication between radio apparatuses equipped with an antenna capable of electrically switching directivity. Further, the present invention is applied to a radio communication system including a radio apparatus capable of avoiding interference even when not passing through a base station in communication between radio apparatuses equipped with an antenna capable of electrically switching directivity. The Furthermore, another object of the present invention is applied to a wireless communication method capable of avoiding interference even in the case of not passing through a base station in communication between wireless devices equipped with antennas capable of electrically switching directivity. .

It is a conceptual diagram of the radio | wireless communications system by embodiment of this invention. FIG. 2 is a functional block diagram showing an internal configuration of the wireless device shown in FIG. 1 and a perspective view of an antenna mounted on the wireless device. FIG. 3 is a plan layout view of the antenna element shown in FIG. 2. It is a figure which shows the beam pattern of the antenna shown in FIG. 2 is a timing chart showing operation timings of the wireless communication system shown in FIG. 1. 3 is a flowchart for explaining an operation when wireless communication is performed between two wireless devices illustrated in FIG. 1.

Explanation of symbols

  1-7 antenna element, 1D-6D varactor diode, 10-15 wireless device, 20-25 antenna, 30 wireless communication space, 40 beam pattern switching means, 50 receiving means, 60 transmitting means, 100 wireless communication system.

Claims (9)

A wireless device that transmits a signal to a communication partner according to a predetermined wireless communication protocol,
An antenna that can electrically switch the beam pattern;
Beam pattern switching means for switching the beam pattern of the antenna to a plurality during the standby period;
When the beam pattern switching means switches the beam pattern to the plurality, the antenna detects the radio wave having the maximum intensity from the plurality of radio waves received by the antenna, and the beam pattern when the detected radio wave is received Beam pattern extracting means for extracting
A radio apparatus comprising: a transmission unit configured to set a beam pattern different from the beam pattern extracted by the beam pattern extraction unit to the antenna and transmit the signal to the communication partner when transmitting the signal to the communication partner.   The radio apparatus according to claim 1, wherein the beam pattern switching unit holds a plurality of beam patterns, and switches the beam pattern of the antenna to the plurality according to the held beam patterns.   The transmission means holds a map in which a plurality of intensities for the plurality of radio waves are associated with the plurality of beam patterns, and a beam pattern different from the beam pattern from the beam pattern extraction means is referred to the map. The wireless device according to claim 1, wherein the wireless device is extracted. The antenna is
A feeding element;
And at least one parasitic element loaded with a variable capacitance element,
The radio apparatus according to any one of claims 1 to 3, wherein the beam pattern switching unit changes a beam pattern of the antenna by changing at least one capacitance of the variable capacitance element. A wireless communication system for transmitting and receiving signals according to a predetermined wireless communication protocol,
A first beam pattern when a radio wave from a wireless device other than the communication partner is received while switching to a plurality of beam patterns during the standby period, and a radio wave having the maximum intensity is received based on the received radio waves. A first radio apparatus that transmits a signal using a second beam pattern different from the detected first beam pattern when transmitting a signal;
A radio wave from the first radio apparatus is received while switching a plurality of beam patterns, a third beam pattern that minimizes interference is extracted based on the received radio waves, and the extracted third beam pattern is extracted. A wireless communication system comprising: a second wireless device that transmits a signal to the first wireless device using a beam pattern.   The wireless communication system according to claim 5, wherein the first wireless device holds a plurality of beam patterns and switches the beam patterns to the plurality according to the held plurality of beam patterns. The first wireless device is:
A first antenna capable of electrically switching the beam pattern;
First beam pattern switching means for switching a plurality of beam patterns of the first antenna during the standby period;
When the beam pattern is switched to the plurality by the first beam pattern switching means, the first antenna detects a radio wave having the maximum intensity from a plurality of radio waves received, and the detected radio wave is received. First beam pattern extraction means for extracting the first beam pattern when
When transmitting the signal, the second beam pattern different from the first beam pattern extracted by the first beam pattern extracting means is set in the first antenna to transmit the signal. Transmission means,
The second wireless device is
A second antenna capable of electrically switching the beam pattern;
Second beam pattern switching means for switching a plurality of beam patterns of the second antenna when receiving radio waves from the first wireless device;
A third beam pattern that minimizes the interference is extracted based on a plurality of radio waves received by the second antenna when the beam pattern is switched to the plurality by the second beam pattern switching means. Second beam pattern extraction means;
6. The wireless communication system according to claim 5, further comprising: a second transmission unit that transmits a signal to the first wireless device using the third beam pattern extracted by the second beam pattern extraction unit. . A wireless communication method for transmitting and receiving signals according to a predetermined wireless communication protocol,
When the transmitter receives radio waves from a wireless device other than the communication partner while switching to multiple beam patterns during the standby period, and receives radio waves with the maximum intensity based on the received radio waves. A first step of detecting one beam pattern;
A second step in which a transmitter transmits a signal using a second beam pattern different from the detected first beam pattern when transmitting a signal to a communication partner;
A third step of receiving a radio wave from the transmitter while switching a plurality of beam patterns, and extracting a third beam pattern having a minimum interference based on the received radio waves;
And a fourth step in which a receiver transmits a signal to the transmitter using the extracted third beam pattern. In the first step, the beam pattern is switched to a plurality according to a plurality of beam patterns preset in the transmitter,
The radio communication method according to claim 8, wherein, in the third step, the beam pattern is switched to a plurality according to a plurality of beam patterns preset in the receiver.

Images