JP2006287669A - Radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication apparatus which improves channel capacity and transmission quality. <P>SOLUTION: A base station 200 is provided with: a plurality of antennas 210; an MIMO transmission processing portion 260 which forms a sending signal in format of MIMO transmission and transmits it through the antennas 210; a transmission beam forming unit 255 which forms the sending signal in format of directive transmission and transmits it through the antennas 210; and a communication system switching controller 240 which switches the MIMO transmission means and the directive transmission means in response to at least either transmission quality of the MIMO transmission and transmission quality of the directive transmission. By the above constitution, since the MIMO transmission means and the directive transmission means are switched in response to at least either transmission quality of the MIMO transmission and transmission quality of the directive transmission, flexible switching of communication system according to actual transmission status is attained, and the radio communication apparatus which improves channel capacity and transmission quality in communication system is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication device, and more particularly to a wireless communication device capable of communication using a MIMO communication method or a directional communication method.

  In recent years, MIMO (Multiple-Input / Multiple-Output) communication has attracted attention as a technology that enables large-capacity data communication such as images. One of the MIMO communications is a space division multiplexing (SDM). In this SDM, different transmission data (substreams) are transmitted from a plurality of antennas on the transmission side, and on the reception side, a plurality of transmission data mixed on the propagation path are separated into original transmission data using the propagation path estimation value. (For example, refer to Patent Document 1).

  In practice, in SDM, a signal transmitted from a transmission apparatus is received by the number of antennas equal to or greater than the number of transmission apparatuses, and is based on a pilot signal inserted in a signal received by each antenna. The propagation path characteristics between antennas are estimated. This estimated propagation path characteristic H is represented by a 2 × 2 matrix when there are two transmitting antennas and two receiving antennas, for example. In the SDM scheme, the transmission signal (substream) transmitted from each transmission antenna is obtained based on the reception signal obtained by each reception antenna using the independence of the obtained propagation path characteristic H.

  However, if the correlation of the propagation path characteristic H is high and the independence is low, it is difficult to separate a plurality of transmission data mixed on the propagation path on the reception side, and the communication capacity and communication quality are deteriorated.

In order to solve this problem, in the communication system disclosed in Patent Document 2, the communication method is changed depending on whether the system with which the mobile station communicates is a large cell system or a small and medium cell system. That is, as shown in FIG. 7B, in a small and medium cell system in which the correlation of the propagation path characteristics H tends to be low, high-speed communication is realized by performing communication using MIMO. On the other hand, as shown in FIG. 7A, in a large cell system in which the correlation of the propagation path characteristic H tends to be high, MIMO communication is not performed, but directional transmission is performed using a plurality of antennas, and the propagation path characteristic is Degradation of communication capacity and communication quality due to high correlation of H is reduced.
JP 2002-44051 A JP 2003-338781 A

  However, in the above conventional communication system, although the communication system changes depending on whether the system with which the mobile station communicates is a large cell system or a small to medium cell system, the communication system to be selected once the system with which the mobile station communicates is determined is It is fixed. For this reason, there is a problem that a communication method suitable for the actual propagation path characteristics is not applied, and there is a problem that communication capacity and communication quality are deteriorated.

  The present invention has been made in view of this point, and an object of the present invention is to provide a wireless communication apparatus that improves communication capacity and communication quality.

  The wireless communication apparatus of the present invention includes a plurality of antennas, MIMO transmission means for forming a transmission signal in a MIMO communication format and transmitting it through the antenna, and forming a transmission signal in a directional communication format through the antenna. Directional transmission means for transmitting the communication method, and communication method switching control means for switching the MIMO transmission means and the directional transmission means in accordance with at least one of the communication quality of the MIMO communication and the communication quality of the directional communication. The structure which comprises is taken.

  The wireless communication apparatus of the present invention includes a first reception quality measuring unit that measures the reception quality of a transmission signal transmitted in the MIMO communication format, and a second that measures the reception quality of the transmission signal transmitted in the directional communication format. Communication method switching for switching the communication method on the transmission side of the transmission signal based on at least one of the measurement results of the reception quality measurement means, and the first reception quality measurement means and the second reception quality measurement means The communication system switching information generating means for generating information and the transmission means for transmitting the communication system switching information to the transmitting side are employed.

  ADVANTAGE OF THE INVENTION According to this invention, the radio | wireless communication apparatus which improves communication capacity and communication quality can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment, the same components are denoted by the same reference numerals, and the description thereof will be omitted because it is duplicated.

(Embodiment 1)
As shown in FIG. 1, the mobile station 100 includes a plurality of antennas 110, an RF receiver 115, a MIMO reception processor 120, a MIMO communication state measurement unit 125, a diversity reception signal processor 130, and a directional communication state. A measurement unit 135, a communication system switching determination unit 140, a diversity transmission signal processing unit 145, a MIMO transmission processing unit 150, and an RF transmission unit 155 are included.

  RF receiving section 115 receives the received signals received by antenna 110-1 and antenna 110-2, performs predetermined processing (such as down-conversion), and outputs the result to MIMO reception processing section 120 and diversity reception signal processing section 130. To do.

  MIMO reception processing section 120 demodulates a signal transmitted by MIMO from base station 200 described later. Specifically, the transmission data and the pilot signal for MIMO transmitted from the base station 200 are demodulated.

  MIMO communication state measuring section 125 measures the communication quality in MIMO communication, for example, received SIR (Signal to Interference Ratio), based on the MIMO pilot signal demodulated by MIMO reception processing section 120.

  Diversity received signal processing section 130 demodulates the signal transmitted from base station 200 with directivity. Specifically, the transmission data and the beamforming pilot signal transmitted from the base station 200 with directivity are demodulated.

  Directional communication state measuring section 135 measures communication quality in directional communication, for example, received SIR, based on the beamforming pilot signal demodulated by diversity reception signal processing section 130.

  The communication system switching determination unit 140 is based on at least one of the reception SIR in the MIMO communication measured by the MIMO communication state measurement unit 125 and the reception SIR in the directional communication measured by the directional communication state measurement unit 135. Thus, it is determined (“switching determination”) whether or not to switch communication methods (MIMO communication and directional communication).

  Specifically, the “switching determination” is performed as follows, for example. As a first example, the communication system switching determination unit 140 compares the reception SIR in the MIMO communication measured by the MIMO communication state measurement unit 125 with a predetermined threshold, and the reception in the MIMO communication as a result of the comparison. When the SIR is larger than a predetermined threshold, the MIMO communication is selected. On the other hand, when the received SIR in the MIMO communication is equal to or less than a predetermined threshold, communication method switching determination unit 140 selects directional communication.

  As a second example, the communication method switching determination unit 140 compares the received SIR in the directional communication measured by the directional communication state measurement unit 135 with a predetermined threshold value, and compares the result. When the reception SIR in the directional communication is larger than a predetermined threshold value, directional communication is selected. On the other hand, when the reception SIR in the directional communication is equal to or less than a predetermined threshold value, communication method switching determination unit 140 selects MIMO communication.

  As a third example, the communication method switching determination unit 140 includes the received SIR in the MIMO communication measured by the MIMO communication state measurement unit 125 and the directional communication measured by the directivity communication state measurement unit 135. Is compared with the received SIR. As a result of the comparison, when the reception SIR in the directional communication is larger than the reception SIR in the MIMO communication, the communication method switching determination unit 140 selects the directional communication. On the other hand, when the reception SIR in the MIMO communication is larger than the reception SIR in the directional communication, the communication method switching determination unit 140 selects the MIMO communication.

  Then, the communication system switching determination unit 140 transmits the identification information of the communication system selected by the above “switching determination” using the current communication system. That is, the communication system switching determination unit 140 outputs the identification information of the communication system selected by the “switching determination” to the MIMO transmission processing unit 150 when currently performing the MIMO communication. On the other hand, the communication system switching determination unit 140 outputs identification information of the communication system selected by the “switching determination” to the diversity transmission signal processing unit 145 when currently performing directional communication. That is, the communication method selected by the communication method switching determination unit 140 is reflected from the next reception and transmission, and is not reflected immediately after selection. Note that the initial state at the start of communication is set to either MIMO communication or directional communication.

  The diversity transmission signal processing unit 145 forms transmission data in the form of diversity communication, and also forms communication method identification information in the form of diversity communication. Then, the transmission data and communication method identification information formed in the diversity communication format are output to the RF transmission unit 155.

  When the communication scheme identification information indicating that the MIMO communication is selected is input, the MIMO transmission processing unit 150 forms transmission data in the MIMO communication format and also forms the communication scheme identification information in the MIMO communication format. . The transmission data and communication method identification information formed in the MIMO communication format are output to the RF transmission unit 155.

  The RF transmission unit 155 performs predetermined processing (such as up-conversion) on the transmission data and communication scheme identification information from the diversity transmission signal processing unit 145 and the MIMO transmission processing unit 150, and via the antenna 110-1 and the antenna 110-2. Send.

  As shown in FIG. 2, the base station 200 includes antennas 210-1 to 210-4, an RF receiving unit 215, an arrival direction estimation processing unit 220, a reception beam forming unit 225, a received signal processing unit 230, and a MIMO reception process. Unit 235, communication method switching control unit 240, buffer 245, transmission data generation unit 250, transmission beam forming unit 255, MIMO transmission processing unit 260, transmission beam forming unit 265, and transmission pilot generation unit 270 , MIMO pilot generation section 275 and RF transmission section 280.

  The RF reception unit 215 inputs the reception signals received by the antennas 210-1 to 210-4 and performs predetermined processing (such as down conversion). Each of the antennas 210-1 to 210-4 has a separation distance of λ / 2 or less (λ is a wavelength of a carrier wave) with respect to the adjacent antenna 210, so that directional communication is possible.

  The direction-of-arrival estimation processing unit 220 receives a reception signal after being received by each antenna 210 and subjected to predetermined processing, and based on a pilot signal component transmitted from the mobile station 100 included in the reception signal, The direction in which the received signal arrives (this corresponds to the direction in which the mobile station 100 currently exists) is estimated, and the estimation result is used as direction-of-arrival information to receive beam forming unit 225, transmit beam forming unit 255 and transmit beam forming unit. To H.265.

  The reception beam forming unit 225 forms a reception beam in the direction indicated by the arrival direction information. In other words, each received signal after being subjected to predetermined processing by the RF receiving unit 215 is weighted so that reception directivity is formed in the direction indicated by the arrival direction information. Each weighted reception signal is output to reception signal processing section 230.

  The reception signal processing unit 230 receives each weighted reception signal and performs demodulation processing. If the communication system identification information transmitted from the mobile station 100 is included in the received signal after demodulation, the communication system identification information is output to the communication system switching control unit 240.

  The MIMO reception processing unit 235 inputs an output signal from the RF reception unit 215 corresponding to the reception signals received by the antenna 210-1 and the antenna 210-4, and performs MIMO demodulation. If the communication system identification information transmitted from the mobile station 100 is included in the received signal after demodulation, the communication system identification information is output to the communication system switching control unit 240. Here, since the antenna 210-1 and the antenna 210-4 are the farthest away and considered to have the lowest correlation, the received signals received by these antennas were used. Any received signal may be used, and any received signal received by the antenna 210 having a separation interval larger than λ / 2 may be used.

  The communication method switching control unit 240 receives communication method identification information from the received signal processing unit 230 or the MIMO reception processing unit 235, and switches the method for transmitting transmission data. Specifically, the communication system identification information is sent to the buffer 245 to switch the output destination of the transmission data from the buffer 245 to the transmission beam forming unit 255 or the MIMO transmission processing unit 260.

  The buffer 245 receives the transmission data generated by the transmission data generation unit 250, and switches the output destination of the transmission data to the transmission beam forming unit 255 or the MIMO transmission processing unit 260 under the control of the communication method switching control unit 240. That is, the data is output to the transmission beam forming unit 255 or the MIMO transmission processing unit 260 corresponding to the communication method identification information from the communication method switching control unit 240.

  The transmission beam forming unit 255 inputs transmission data from the buffer 245 and modulates it to form a transmission signal. The transmission beam forming unit 255 then weights a plurality of transmission signals (corresponding to the number of antennas 210) so that directivity is formed in the direction corresponding to the arrival direction information from the arrival direction estimation processing unit 220. And output to the RF transmitter 280.

  The MIMO transmission processing unit 260 receives transmission data from the buffer 245 and forms a transmission signal in the MIMO communication format. Then, the MIMO transmission processing unit 260 performs modulation processing on each formed transmission signal and outputs the transmission signal so as to be transmitted from the corresponding antenna 210 via the RF transmission unit 280. Here, since the antenna 210-1 and the antenna 210-4 are farthest from each other and considered to have the lowest correlation, these antennas are used for transmission. Any antenna 210 having a spacing greater than λ / 2 may be used.

  Transmit beam forming section 265 receives and modulates the pilot signal generated by transmit pilot generating section 270. Then, transmission beam forming section 265 weights the modulated pilot signal so that directivity is formed in the direction corresponding to the arrival direction information from arrival direction estimation processing section 220, and a plurality of transmission signals are transmitted. Form. The plurality of transmission signals are output so as to be transmitted from the corresponding antenna 210 via the RF transmission unit 280. Here, an antenna 210 other than the antenna used for transmitting a MIMO pilot signal, which will be described later, is used.

  The MIMO pilot generation unit 275 generates a plurality of MIMO pilot signals, performs modulation processing on each MIMO pilot signal, and outputs the signals to be transmitted from the corresponding antenna 210 via the RF transmission unit 280. Here, since the antenna 210-1 and the antenna 210-4 are farthest from each other and considered to have the lowest correlation, these antennas are used for transmission. Any antenna 210 having a spacing greater than λ / 2 may be used.

  The RF transmission unit 280 inputs various signals and performs predetermined processing (up-conversion etc.). Then, the signal after being subjected to the predetermined processing is transmitted via the corresponding antenna 210.

  In the above description, communication method switching determining section 140 switches communication methods (MIMO communication and directional communication) based on at least one of reception SIR in MIMO communication and reception SIR in directional communication. Whether or not ("switching determination") is to be performed. However, the present invention is not limited to this, and switching determination may be performed based on the frame error rate instead of the reception SIR.

  That is, the frame error rate in the currently used communication is measured, and when this frame error rate is equal to or higher than a predetermined threshold, switching to another communication method is performed. Specifically, when currently performing MIMO communication, the MIMO communication state measurement unit 125 measures the frame error rate in MIMO communication and outputs the measurement result to the communication method switching determination unit 140. When the frame error rate measurement result is larger than a predetermined threshold value, the communication method switching determination unit 140 selects directional communication. When directional communication is currently being performed, the directional communication state measurement unit 135 measures the frame error rate in directional communication and outputs the measurement result to the communication method switching determination unit 140. When the frame error rate measurement result is larger than a predetermined threshold value, the communication method switching determination unit 140 selects MIMO communication.

  As described above, according to the first embodiment, the base station 200 has a plurality of antennas 210, a MIMO transmission processing unit 260 that forms a transmission signal in the form of MIMO communication, and transmits the transmission signal via the antenna 210, and directs the transmission signal. A transmission beam forming unit 255 that is formed in the form of directional communication and transmits via the antenna 210, and the MIMO transmission processing unit 260 according to at least one of the communication quality of the MIMO communication and the communication quality of the directional communication And a communication system switching control unit 240 for switching the transmission beam forming unit 255.

  By doing so, the MIMO transmission means and the directional transmission means are switched according to at least one of the communication quality of MIMO communication and the communication quality of directional communication, so that a flexible communication method according to the actual communication situation Switching is possible, and a wireless communication apparatus that improves communication capacity and communication quality in the communication system can be realized.

  Further, each antenna 210 has a separation distance between adjacent antennas 210 equal to or less than a half wavelength of the carrier wave, and the MIMO transmission processing unit 260 uses a group of antennas 210 whose separation distance is larger than the half wavelength of the carrier wave. The transmission beam forming unit 255 transmits using a group of antennas 210 whose separation distance is equal to or less than a half wavelength of the carrier wave.

  By doing so, it is not necessary to separately prepare an antenna for MIMO communication and an antenna for directional communication, so that space saving and cost reduction of the wireless communication device can be realized.

  Moreover, according to Embodiment 1, the MIMO communication state measuring unit 125 that measures the reception quality of the transmission signal transmitted to the mobile station 100 in the MIMO communication format, and the reception of the transmission signal transmitted in the directional communication format. The communication method on the transmission side of the transmission signal is switched based on at least one of the measurement results of the directivity communication state measurement unit 135 that measures quality, the MIMO communication state measurement unit 125, and the directivity communication state measurement unit 135. A communication system switching determination unit 140 that generates communication system switching information and an RF transmission unit 155 that transmits the communication system switching information (communication system identification information) to the transmission side are provided.

  By doing so, the transmission side (base station 200) that receives the communication mode switching information (communication mode identification information) can be switched flexibly according to the actual communication status, and the communication capacity and communication quality in the communication system can be changed. It is possible to realize a wireless communication device that improves the above.

(Embodiment 2)
In the first embodiment, the description has been made on the assumption of one-to-one communication between the mobile station 100 and the base station 200. In contrast, in the second embodiment, a case will be described in which a plurality of mobile stations 100 communicate with a base station.

  As shown in FIG. 3, base station 300 communicates with a plurality of mobile stations 100 (two mobile stations 100-1 and 100-2 in the figure). Communication between base station 300 and mobile station 100-1 is directional communication, while communication between base station 300 and mobile station 100-2 is MIMO communication. .

  When base station 300 in the second embodiment forms directivity for mobile station 100-1 performing directional communication, null direction is applied to mobile station 100-2 performing MIMO communication. The directivity is controlled so that (low gain direction) is directed. By doing so, the null direction (low gain direction) can be directed to the mobile station 100-2 performing MIMO communication, which is actually likely to be located at a short distance from the base station 300. Therefore, it is possible to reduce interference with a wireless communication device located at a short distance.

  As illustrated in FIG. 4, the base station 300 includes a transmission beam forming unit 310 and a transmission beam forming unit 320.

  Transmit beam forming section 310 receives arrival direction information for mobile station 100-1 and mobile station 100-2 from arrival direction estimation processing section 220. In addition, the transmission beam forming unit 310, from the communication method switching control unit 240, performs communication between the mobile station identification information of the mobile station 100 performing communication and the mobile station 100 specified by the mobile station identification information. The communication system identification information indicating whether or not Specifically, identification information of mobile station 100-1 performing directional communication and communication method identification information indicating that directional communication is performed are input in association with each other. Further, identification information of mobile station 100-2 performing MIMO communication and communication method identification information indicating that MIMO communication is performed are input in association with each other.

  The transmission beam forming unit 310 then performs mobile communication (here, mobile station) performing MIMO communication when forming directivity for the mobile station (here, mobile station 100-1) performing directional communication. The directivity is formed so that the null direction (low gain direction) is directed to the direction of the station 100-2).

  Transmit beam forming section 320 receives arrival direction information about mobile station 100-1 and mobile station 100-2 from arrival direction estimation processing section 220. In addition, the transmission beam forming unit 320 receives, from the communication system switching control unit 240, which communication is performed by the mobile station identification information of the mobile station 100 with which communication is performed and the mobile station 100 specified by the mobile station identification information. The communication system identification information indicating whether or not Specifically, identification information of mobile station 100-1 performing directional communication and communication method identification information indicating that directional communication is performed are input in association with each other. Further, identification information of mobile station 100-2 performing MIMO communication and communication method identification information indicating that MIMO communication is performed are input in association with each other.

  The transmission beam forming unit 320 then performs mobile communication (here, mobile station) performing MIMO communication when forming directivity for the mobile station (here, mobile station 100-1) performing directivity communication. The directivity is formed so that the null direction (low gain direction) is directed to the direction of the station 100-2).

  As described above, according to the second embodiment, base station 300 is configured to direct a plurality of antennas 210, a MIMO transmission processing unit 260 that forms a transmission signal in a MIMO communication format and transmits it via antenna 210, and a transmission signal. A transmission beam forming unit 310 that is formed in the form of directional communication and transmits via the antenna 210, a MIMO transmission processing unit 260 and at least one of the communication quality of the MIMO communication and the communication quality of the directional communication, and A communication system switching control unit 240 that switches the transmission beam forming unit 310 is provided.

  Furthermore, the base station 300 is a radio communication device that communicates with a first radio reception device (here, the mobile station 100-1) and a second radio reception device (here, the mobile station 100-2), A direction-of-arrival estimation processing unit 220 that estimates directions in which the first and second radio reception apparatuses are located, and a transmission beam forming unit 310 performs the directional communication with the first radio reception apparatus and performs the second communication. When performing the MIMO communication with the wireless reception device of the first, the transmission directivity is formed in the direction in which the estimated first wireless reception device is located, and the direction in which the second wireless reception device is located The transmission directivity is formed so that the null direction is directed.

  By doing so, the null direction (low gain direction) can be directed to the mobile station 100-2 performing MIMO communication, which is actually likely to be located at a short distance from the base station 300. Therefore, it is possible to reduce interference with a wireless communication device located at a short distance.

(Other embodiments)
In the first embodiment and the second embodiment, the communication system switching determination unit of the mobile station determines whether or not to switch communication systems (MIMO communication and directional communication) (“switching determination”). However, the present invention is not limited to this, and information necessary for the switching determination may be transmitted from the mobile station to the base station, and the base station may perform the switching determination based on the information. The case where it applies to Embodiment 1 is demonstrated as an example.

  As shown in FIG. 5, mobile station 400 of the present embodiment has communication state information acquisition section 410. The communication state information acquisition unit 410 inputs the reception SIR in the MIMO communication measured by the MIMO communication state measurement unit 125 and the reception SIR in the directional communication measured by the directivity communication state measurement unit 135. Communication state information acquisition section 410 then applies a predetermined process to diversity transmission signal processing section 145 or MIMO transmission processing section 150 for at least one of the received reception SIR in MIMO communication and reception SIR in directional communication. Then, the data is transmitted to the base station 500 via the RF transmission unit 155.

  As shown in FIG. 6, base station 500 of the present embodiment includes reception signal processing section 510, MIMO reception processing section 520, and communication method switching determination section 530.

  Received signal processing section 510 receives each weighted received signal and performs demodulation processing. If the received signal after demodulation includes communication state information transmitted from mobile station 400 (that is, reception SIR in MIMO communication and reception SIR in directional communication), the communication state information is switched to communication method. It outputs to the determination part 530.

  The MIMO reception processing unit 520 receives an output signal from the RF reception unit 215 corresponding to the reception signal received by the antenna 210-1 and the antenna 210-4, and performs MIMO demodulation. When the communication state information transmitted from the mobile station 400 is included in the received signal after the demodulation process, the communication state information is output to the communication method switching determination unit 530.

  Similar to communication method switching determination unit 140 of mobile station 100, communication method switching determination unit 530 is at least one of reception SIR in MIMO communication and reception SIR in directional communication measured by directional communication state measurement unit 135. Based on one of them, it is determined whether or not to switch communication schemes (MIMO communication and directional communication) (“switch determination”). In this case, a frame error rate may be used instead of the reception SIR.

  As described above, the base station 500 forms a plurality of antennas 210, a MIMO transmission processing unit 260 that forms a transmission signal in the MIMO communication format and transmits it through the antenna 210, and a transmission signal in the directional communication format. Based on at least one of the communication quality of MIMO communication and the communication quality of directional communication fed back from the reception side (mobile station 400) of the transmission signal and the transmission beam forming unit 255 that transmits via the antenna 210 A communication method switching determination unit 530 that determines switching between the MIMO transmission processing unit 260 and the transmission beam forming unit 255, and the MIMO transmission processing unit 260 and the transmission beam forming unit according to the determination result of the communication method switching determination unit 530 A communication system switching control unit 240 for switching 255 is provided.

  By doing so, the MIMO transmission means and the directional transmission means are switched according to at least one of the communication quality of MIMO communication and the communication quality of directional communication, so that a flexible communication method according to the actual communication situation Switching is possible, and a wireless communication apparatus that improves communication capacity and communication quality in the communication system can be realized.

  Also, a MIMO communication state measuring unit 125 that measures the reception quality of a transmission signal transmitted to the mobile station 400 in the MIMO communication format, and a directional communication state that measures the reception quality of the transmission signal transmitted in the directional communication format. A measurement unit 135, and a communication state information acquisition unit 410 that transmits at least one of the measurement results of the MIMO communication state measurement unit 125 and the directivity communication state measurement unit 135 to the transmission side of the transmission signal are provided.

  By doing so, the transmission side (base station 500) that receives the communication mode switching information (communication mode identification information) can be switched flexibly according to the actual communication status, and the communication capacity and communication quality in the communication system can be changed. It is possible to realize a wireless communication device that improves the above.

  The wireless communication device of the present invention has an effect of improving communication capacity and communication quality, and is useful as a wireless communication device capable of switching between the MIMO communication method and the directional communication method.

Block diagram showing a configuration of a mobile station according to Embodiment 1 of the present invention. FIG. 3 is a block diagram showing a configuration of a base station according to the first embodiment. The figure for explanation of the system of the second embodiment The block diagram which shows the structure of the base station of FIG. The block diagram which shows the structure of the mobile station which concerns on other embodiment. The block diagram which shows the structure of the base station which concerns on other embodiment. A diagram for explaining a conventional communication system

Explanation of symbols

100, 400 Mobile station 110, 210 Antenna 115, 215 RF receiving unit 120, 235, 520 MIMO reception processing unit 125 MIMO communication state measuring unit 130 Diversity received signal processing unit 135 Directional communication state measuring unit 140, 530 Communication system switching determination Unit 145 diversity transmission signal processing unit 150, 260 MIMO transmission processing unit 155, 280 RF transmission unit 200, 300, 500 base station 220 arrival direction estimation processing unit 225 reception beam forming unit 230, 510 reception signal processing unit 240 communication system switching control Unit 245 buffer 250 transmission data generation unit 255, 265, 310, 320 transmission beam forming unit 270 transmission pilot generation unit 275 MIMO pilot generation unit 410 communication state information acquisition unit

Claims (4)

Multiple antennas,
MIMO transmission means for forming a transmission signal in the form of MIMO communication and transmitting via the antenna;
Directional transmission means for forming a transmission signal in the form of directional communication and transmitting via the antenna;
A communication mode switching control means for switching the MIMO transmission means and the directional transmission means in accordance with at least one of the communication quality of the MIMO communication and the communication quality of the directional communication;
A wireless communication apparatus comprising: A wireless communication device that communicates with a first wireless reception device and a second wireless reception device,
Comprising estimation means for estimating a direction in which the first and second wireless reception devices are located;
The directional transmission unit performs the directional communication with the first wireless reception device and performs the MIMO communication with the second wireless reception device. 2. The wireless communication according to claim 1, wherein the transmission directivity is formed in a direction in which the second wireless reception device is located, and the transmission directivity is formed so that a null direction is directed in a direction in which the second wireless reception device is located. apparatus. Each antenna has a separation distance between adjacent antennas equal to or less than a half wavelength of the carrier wave,
The MIMO transmission means transmits using the group of antennas whose separation distance is larger than a half wavelength of the carrier wave,
2. The wireless communication apparatus according to claim 1, wherein the directional transmission unit transmits the antenna using a group of antennas whose separation distance is equal to or less than a half wavelength of the carrier wave. First reception quality measuring means for measuring reception quality of a transmission signal transmitted in the MIMO communication format;
Second reception quality measuring means for measuring reception quality of a transmission signal transmitted in a directional communication format;
Communication method switching for generating communication method switching information for switching the communication method on the transmission side of the transmission signal based on at least one of the measurement results in the first reception quality measurement unit and the second reception quality measurement unit Information generating means;
Transmitting means for transmitting the communication method switching information to the transmitting side;
A wireless communication apparatus comprising:

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