JP2007214758A - Wireless communication apparatus and antenna control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless communication apparatus and an antenna control method whereby a high transmission capacity is obtained with a simple antenna configuration even under an environment wherein environmental variations are comparatively small. <P>SOLUTION: A received power measurement section 17 measures received power of each signal received by using antenna element groups 15-1, 15-2, and a correlation value measurement section 1 similarly measures a correlation value of each signal received by them. A transmission capacity reference section 20 refers to a transmission capacity table 19 wherein a transmission capacity is stored in advance in cross reference with the received power and the correlation value to acquire the transmission capacities of the respective antenna element groups associated with the received power and the correlation value. A switch switching control section 21 compares the respective transmission capacities acquired by the transmission capacity reference section 20 and switch controls a switch 14 to use any of the antenna element groups corresponding to a greater transmission capacity for a transmission antenna. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention improves the MIMO transmission characteristics by utilizing the correlation of the antenna configuration, the difference in SNR, etc. in an environment where the environmental variation is relatively small, such as a multi-user MIMO relay antenna, The present invention relates to a radio communication apparatus and an antenna control method that can be used for a method of selectively using the vicinity of a base station and a zone edge in application at a base station in high places.

  In recent years, the IEEE802.11g standard, the IEEE802.11a standard, and the like are remarkable as high-speed wireless access systems using the 2.4 GHz band or the 5 GHz band. In these systems, an orthogonal frequency division multiplexing (OFDM) modulation method, which is a technique for stabilizing characteristics in a multipath fading environment, is used, and a transmission rate of 54 Mbps at the maximum is realized. However, the transmission rate here is a transmission rate on the physical layer. Actually, the transmission efficiency in the MAC (Medium Access Control) layer is about 50 to 70%. The upper limit is about 30 Mbps.

  On the other hand, in the world of wired LANs, the provision of 100 Mbps high-speed lines has become widespread due to the widespread use of Ethernet (registered trademark) 100Base-T interface and FTTH (Fiber to the home) using optical fiber in each home. In the world of wireless LAN, further increase in transmission speed is demanded.

  As a technique for that purpose, a MIMO (Multiple-Input Multiple-Output) technique is effective. This MIMO technology is such that different independent signals are transmitted on the same channel from a plurality of transmitting antennas on the transmitting station side, and signals are received using the same plurality of antennas on the receiving station side, between each transmitting antenna / receiving antenna. The transfer function matrix is obtained, the independent signal transmitted from each antenna is estimated on the transmitting station side using this matrix, and the data is reproduced.

  Furthermore, a multi-user MIMO system has recently attracted attention as a means for realizing virtual MIMO transmission by having a large number of elements in a base station and constructing a plurality of MIMO transmission paths with a plurality of users. ing.

  The theoretical maximum transmission capacity C using the MIMO technique can be theoretically derived from the following equation (see Non-Patent Document 1, for example).

In the above equation (1), ρ is a signal-to-noise power ratio, M is the number of transmitting antenna elements, and _IN is a unit matrix of the number of receiving elements N × N. H is a transfer function matrix representing a propagation channel response between the transmitting antenna and the receiving antenna, and can be described by the following mathematical formula (2).

Here, h _ij is the channel response of the propagation path from the i-th transmitting antenna to the j-th receiving antenna. From Equation (1), in MIMO transmission, it is important to first increase the signal-to-noise ratio (SNR) as in the conventional system. Furthermore, in MIMO transmission, it is necessary to lower the correlation between antennas.

  Here, since the SNR is determined by the distance between the base station and the terminal, the transmission power, the prospect between the base station and the terminal, and the like, it is basically determined by the positional relationship between the base station and the terminal. Is a factor. On the other hand, it is known that the correlation greatly depends on the antenna configuration used (number of elements, element directivity, element spacing, polarization, etc.), propagation channel (angle, delay spread), and the like. It is known that this correlation value is relatively low in the indoor environment, but in the outdoor environment, the angle spread of the propagation path is small, so that the correlation between the antennas is very high. Yes.

  FIG. 6 is a conceptual diagram showing the transmission capacity of MIMO transmission when the correlation value is changed with respect to the transfer function matrix H in the case of two transmitting antenna elements and two receiving antenna elements according to the prior art. . FIG. 6 shows the transmission capacity of MIMO transmission when the correlation value is changed with respect to the transfer function matrix H in Equation (1). The horizontal axis represents SNR, and the vertical axis represents transmission capacity. As can be seen from the figure, the transmission capacity of MIMO is significantly reduced due to the extremely high correlation. Therefore, in the MIMO channel, it is very important to lower the correlation between antennas.

  As a technique for performing MIMO transmission while lowering the correlation between antennas, a MIMO configuration using orthogonal polarization shown in FIG. 7 has been proposed (see, for example, Non-Patent Document 2). As shown in FIG. 7, on the transmission side, the signal generation unit 1 generates two signals S1 and S2 having different polarizations orthogonal to each other, and the signals S1 and S2 are respectively transmitted to the transmitters 2-1 and 2-2. Thus, transmission is performed from two orthogonal antennas 3-1 and 3-2. On the reception side, signals from the transmission side are received by the receivers 6-1 and 6-2 using the same two orthogonal antennas 5-1 and 5-2, and the signals S 1 and S 2 are received by the decoding processing unit 7. Take out. In the configuration described above, the degree of discrimination of the polarization in the received signal is slightly degraded by the propagation path 4, but a cross polarization discrimination of about several dB can be ensured in an outdoor environment or the like.

For this reason, by separating two polarizations in advance on the receiving side and using an interference canceller such as zero forcing (ZF) or MMSE (Minimum Mean Square Error), even if the correlation between antennas is high, MIMO It has been reported that the capacity due to transmission does not decrease. Also, with this method, it is possible to reduce the size of the antenna, compared to using an antenna with normal vertical polarization.
I. E. Telatar, “Capacity of multi-tenenna Gaussian channels”, Euro. Trans. Telecommun. , Vol. 1, no. 6, Nov. / Dec. 1999. Paulaj et al. , Introduction to Space Time Wireless Communications, Cambridge Publisher, 2003

  However, the following problems occur in the MIMO configuration using orthogonal polarization according to the above-described prior art. The reception power received with orthogonal polarization is generally smaller than the reception power obtained with vertical polarization. In mobile communication environments, it is known that received power using orthogonal polarization is about 3 dB lower than received power using vertical polarization. FIG. 8 shows a situation where the correlation is high (FIG. 8: correlation = 0.98, 1) in the situation where the correlation is low (FIG. 6: correlation = 0, 0.7). FIG. 5 is a conceptual diagram showing a difference in transmission capacity when it is assumed that the SNR is 3 dB lower.

  As is clear from the figure, even if the correlation can be lowered, an antenna configuration having a high correlation is more advantageous in a region where the SNR is low. Such a region is a case in which wireless communication provides an environment with good visibility due to the zone edge or shadowing. In general, in a mobile communication environment, a dynamic range of about several tens of dB is secured, and the range that SNR can take is large. For this reason, the conventional technique has a problem that an MIMO configuration that is effective in a wide SNR range and difficult to realize is required.

  The present invention has been made in consideration of such circumstances, and the object thereof is simple even in an environment in which environmental fluctuations are relatively small, such as a multi-user MIMO relay antenna. An object of the present invention is to provide a radio communication apparatus and an antenna control method capable of obtaining a high transmission capacity with an antenna configuration.

  In order to solve the above-described problem, the present invention includes a first antenna group including a plurality of antennas, and a first antenna group including a plurality of antennas included in the first antenna group and another wireless communication device. A wireless communication apparatus that performs MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time via a MIMO channel configured by two antenna groups, wherein the first antenna group includes at least The antenna element group includes a plurality of antenna element groups having two or more different characteristics, and based on the received signal power and the correlation value of the received signal received by each of the plurality of antenna element groups, It is characterized by comprising antenna selection means for selecting these as transmitting antennas.

  In order to solve the above-described problem, the present invention includes a first antenna group including a plurality of antennas, and a first antenna group including a plurality of antennas included in the first antenna group and another wireless communication device. A wireless communication apparatus that performs MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time via a MIMO channel configured by two antenna groups, wherein the first antenna group includes at least It consists of a plurality of antenna element groups having two or more different characteristics, and one of the plurality of antenna element groups is used for transmission based on the received signal power of the received signal received by each of the plurality of antenna element groups Antenna selection means for selecting as an antenna element is provided.

  According to the present invention, in the above invention, received power measuring means for measuring a received signal power of a received signal received by each of the plurality of antenna element groups, and a received signal received by each of the plurality of antenna element groups Each of the plurality of antenna element groups based on the correlation value measuring means for measuring the correlation value of the received signal power, the received signal power measured by the received power measuring means, and the correlation value measured by the correlation value measuring means. Transmission capacity acquisition means for acquiring transmission capacity, wherein the antenna selection means is based on the transmission capacity of each of the plurality of antenna element groups acquired by the transmission capacity acquisition means. Any one of the groups is selected as a transmitting antenna.

  According to the present invention, in the above invention, a reception power measurement unit that measures reception signal power of a reception signal received by each of the plurality of antenna element groups is provided, and the antenna selection unit includes the reception power measurement unit. Based on the measured received signal power, any one of the plurality of antenna element groups is selected as a transmitting antenna.

  According to the present invention, in the above invention, the plurality of antenna element groups include an antenna element group including a plurality of antenna elements having vertical polarization, and an antenna element including a plurality of antenna elements having vertical polarization and horizontal polarization. It consists of groups.

  According to the present invention, in the above invention, the plurality of antenna element groups include an antenna element group including a plurality of antenna elements having vertical polarization and an antenna including a plurality of antenna elements having +45 degrees and −45 degrees polarization. It is comprised from an element group.

  The present invention is characterized in that, in the above invention, the plurality of antenna element groups are composed of a plurality of antenna element groups including a plurality of antenna elements orthogonal to three directions.

  According to the present invention, in the above invention, the antenna selection unit is configured to select any one of the plurality of antenna element groups based on a relationship between a threshold value determined by a correlation value acquired in advance from a communication state and the signal reception power. Is selected as a transmitting antenna.

  According to the present invention, in the above invention, the plurality of antenna element groups include a plurality of antenna element groups each including a plurality of antenna elements orthogonal to two directions.

  The present invention is characterized in that, in the above invention, the plurality of antenna element groups include a plurality of antenna element groups including a plurality of antenna elements having directivities in two or more different directions.

  In order to solve the above-described problem, the present invention includes a first antenna group including a plurality of antennas, and a first antenna group including a plurality of antennas included in the first antenna group and another wireless communication device. An antenna control method in a radio communication apparatus for performing MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time via a MIMO channel configured by two antenna groups, the first antenna The group includes a plurality of antenna element groups having at least two or more different characteristics, a step of measuring a received signal power of a received signal received by each of the plurality of antenna element groups, and the plurality of antenna element groups Measuring the correlation value of the received signal received at each of the plurality of antennas based on the received signal power and the correlation value Obtaining a transmission capacity of each of the child groups, and selecting one of the plurality of antenna element groups as a transmitting antenna based on the transmission capacity of each of the plurality of antenna element groups. Features.

  In order to solve the above-described problem, the present invention includes a first antenna group including a plurality of antennas, and a first antenna group including a plurality of antennas included in the first antenna group and another wireless communication device. An antenna control method in a radio communication apparatus for performing MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time via a MIMO channel configured by two antenna groups, the first antenna The group includes a plurality of antenna element groups having at least two or more different characteristics, the step of measuring the received signal power of the received signal received by each of the plurality of antenna element groups, and the received power measuring means Selecting any one of the plurality of antenna element groups as a transmission antenna based on the measured received signal power. And wherein the door.

  According to the present invention, the first antenna group is composed of a plurality of antenna element groups having at least two or more different characteristics, and the received signal received by each of the plurality of antenna element groups is received by the antenna selection means. Based on the received signal power and the correlation value, one of a plurality of antenna element groups is selected as a transmitting antenna. Therefore, there is an advantage that a high transmission capacity can be obtained with a simple antenna configuration even in an environment where environmental fluctuations are relatively small, such as a multi-user MIMO relay antenna.

  Hereinafter, a wireless communication apparatus according to an embodiment of the present invention will be described with reference to the drawings.

A. First Embodiment FIG. 1 is a block diagram showing a configuration of a wireless communication apparatus according to a first embodiment of the present invention. In the figure, a wireless communication apparatus includes a transmission signal generation unit 11, two transmitters 12-1, 12-2, circulators 13-1, 13-2, a switch 14, and antenna element groups 15-1, 15-2, 2; Two receivers 16-1 and 16-2, a received power measuring unit 17, a correlation value measuring unit 18, a transmission capacity table 19, a transmission capacity reference unit 20, and a switch switching control unit 21 are provided.

  The transmission signal generator 11 generates transmission signals S1 and S2 and supplies them to the transmitters 12-1 to 12-2. The transmission signal generation unit 11 has a function of serial-parallel conversion of a signal to be transmitted, for example, when performing spatial division multiplexing transmission in MIMO transmission. In addition, when performing space-time coded transmission, it has a function of converting a signal according to a signal conversion method based on the Alamouti method. This function is a basic function in MIMO transmission, and is disclosed, for example, in “Literature: Daibell, Basic and Elemental Technology of MIMO System, Design / Analysis Technique Workshop in Antenna / Propagation, W29, 30” and the like.

  The transmitters 12-1 and 12-2 receive signals S1 and S2 from either the antenna element group 15-1 or the antenna element group 15-2 selected by the switch 14 via the circulators 13-1 and 13-2. Send. The selection of the transmission antenna will be described later. The receivers 16-1 and 16-2 receive signals from other wireless communication devices (not shown) received by the antenna element group 15-1 and the antenna element group 15-2 controlled to be switched by the switch 14. 1 and 13-2. The received power measuring unit 17 measures the received power of each signal received by the receivers 16-1 and 16-2. The correlation value measuring unit 1 measures the correlation value of each signal received by the receivers 16-1 and 16-2.

  The transmission capacity table 19 preliminarily stores tabulated received power and transmission capacity for correlation values. When the received power and the correlation value of the signal received by each antenna element group are input, the transmission capacity reference unit 20 refers to the transmission capacity table 19 and transmits the received power and the correlation value. Get capacity.

  As described above, the transmission capacity of MIMO transmission can be expressed by the received power and the correlation value, and by obtaining these values, it is possible to determine which antenna element group is appropriate as an antenna to be transmitted. it can. Further, in order to obtain the transmission capacity every time, it is necessary to accurately obtain the propagation channel response. Therefore, the transmission capacity table 19 and the transmission capacity reference unit 20 described above are provided in order to easily obtain the transmission capacity from the obtained received power and the correlation value.

  The switch switching control unit 21 compares the transmission capacities acquired by the transmission capacity reference unit 20, and instructs the switch 14 to perform switching control so that the antenna element group corresponding to the large transmission capacity is used as a transmission antenna. . The switch 14 is configured to connect one of the antenna element groups to the circulators 13-1 and 13-2 in accordance with the switching control instruction from the switch switching control unit 21. As a result, the signals from the transmitters 12-1 and 12-2 are transmitted from the antenna element group 15-1 selected by the switch 14 or the antenna element group 15-2 having the larger transmission capacity. It will be.

  In the first embodiment, a plurality of antenna element groups (two in the first embodiment) are prepared, and the antenna to be used is determined according to the result obtained from the parameters for determining the MIMO transmission capacity such as received power and correlation value. By selecting one of the antenna element groups, good MIMO transmission is realized without depending on the received power. The plurality of antenna element groups are composed of a plurality of antenna elements having different polarization, directivity, arrangement, and element spacing between the antenna element groups. The configuration shown in FIG. 1 includes an antenna element group 15-1 in the Z direction (vertical arrangement) and an antenna element group 15-2 in the X direction (horizontal arrangement) as a plurality of antenna element groups.

  As the plurality of antenna element groups, as described in the second and third embodiments described later, an antenna element group having a vertically polarized wave or a horizontally polarized wave orthogonal thereto, or an antenna having a ± 45 degree polarized wave It may be an element group, a right-handed / left-handed polarized antenna element group, or an antenna element group having different directivities. Further, the number of antenna element groups in FIG. 1 is two, but may be three or more (see FIG. 5 described later).

  Next, FIG. 2 is a flowchart for explaining the antenna control operation of the wireless communication apparatus according to the first embodiment. In the configuration shown in FIG. 1, since there are two types of antenna element groups, that is, antenna element groups 15-1 and 15-2, Steps S1 to S5 and Step S6 shown in FIG. Repeat the process of ~ S10. This step corresponds to the number of antenna element groups. You can start with either one.

  First, a signal is received by the antenna element group (vertically polarized antenna element group) 15-1 (S1), the received power is measured by the received power measuring unit 17 (S2), and the correlation value is measured by the correlation value measuring unit 18. Measure (S3). Next, the received power and the correlation value are input to the transmission capacity reference unit 20 (S4), and the transmission capacity Cv is acquired from the transmission capacity table 19 (S5).

  Similarly, the same processing is performed on the antenna element group (horizontal polarization antenna element) 15-2 (S6 to S10) to acquire the transmission capacity Ch. Next, the switch switching control unit 21 compares the transmission capacity Cv and the transmission capacity Ch to determine whether or not the transmission capacity Cv is larger than the transmission capacity Ch (S11). When the transmission capacity Cv is larger, the switch 14 is instructed to perform switching control so as to select the antenna element group 15-1 (S12). Thereby, the signals from the transmitters 12-1 and 12-2 are transmitted from the antenna element group 15-1 (S14).

  On the other hand, when the transmission capacity Ch is larger, the switch 14 is instructed to perform switching control so as to select the antenna element group 15-2 (S13). Thereby, the signals from the transmitters 12-1 and 12-2 are transmitted from the antenna element group 15-2 (S14).

  According to the first embodiment described above, it is possible to perform MIMO transmission using an antenna most suitable for power given at a location regardless of the location where MIMO communication is performed.

B. Second Embodiment Next, a second embodiment of the present invention will be described.
FIG. 3 is a block diagram showing a configuration of a wireless communication apparatus according to the second embodiment of the present invention. Note that portions corresponding to those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. Unlike the configuration shown in FIG. 1, this configuration is characterized in that the correlation value is not measured, only the received power is measured, and the antenna element group to be used for transmission is determined according to the magnitude of the received power. .

  In general, it is known that an average correlation value depends on, for example, a difference between indoors and outdoors, or a height at which a base station is installed. For example, if the height of the base station is known at the time of installation, and the approximate correlation value is known in advance, the antenna element group can be selected only by the received power, and the transmitting antenna can be efficiently and efficiently operated by a very simple method. Can be determined. In the second embodiment, as a plurality of antenna element groups, an antenna element group 15-1 in the Z direction (vertical arrangement) and an antenna element group 15-3 having a polarization of ± 45 degrees are provided.

  The antenna control operation according to the second embodiment is based on the point that the antenna element group 15-3 of ± 45 degree polarization is used instead of the antenna element group 15-2, and the correlation value is not obtained and the communication state is determined in advance. Based on the threshold value obtained from the difference between the known correlation value and the received power of each antenna element group measured by the received power measuring unit 17, any one of the plurality of antenna element groups is selected by the switch switching control unit 21. This is basically the same as that of the first embodiment described above except that the antenna is determined as a transmission antenna and the switch 14 is controlled to select the antenna element group to be used for transmission.

  In the present embodiment, the switch switching control unit 21 needs some correlation value information. If the correlation value is expected to be approximately a predetermined value in the assumed usage environment of a certain wireless system, it may be fixedly set as a system-specific value. Or, when installing the wireless communication device, the correlation value information may be set to the wireless notification device from the outside. In this case, it is not always necessary to input the correlation value itself as a value. For example, it is possible to select and input indoor / outdoor selection, base station height information at the time of installation, type of wireless system, and the like. Corresponding correlation values can be set by referring to a memory table or the like.

C. Third Embodiment Next, a third embodiment of the present invention will be described.
FIG. 4 is a block diagram showing a configuration of a wireless communication apparatus according to the third embodiment of the present invention. It should be noted that portions corresponding to those in FIG. In the third embodiment, as shown in FIG. 4, as a plurality of antenna element groups, antenna element groups 15-4, antenna element groups 15-5, and antenna element groups 15- in different directions (X, Y, Z) are used. 6 is provided. Here, the direction of each antenna element of the antenna element group 15-4 is X1, Y1, Z1, the direction of each antenna element of the antenna element group 15-5 is X2, Y2, Z2, and each antenna of the antenna element group 15-6. The element directions are X3, Y3, and Z3.

  The transmitters 12-1, 12-2, and 12-3 can be connected to any one of the X, Y, and Z directions of the respective antenna element groups 15-4 to 15-6 in a switchable manner. It has become. That is, the switches 14-1, 14-2, 14-3 can select (X1, X2, X3), (Y1, Y2, Y3), (Z1, Z2, Z3), It is also possible to select an antenna element such as (X1, Y2, Z3). In this configuration, a general-purpose switch such as a three-branch switch can be used as the switches 14-1, 14-2, and 14-3, which can be more easily mounted.

  The antenna control operation in the third embodiment is that the received power measuring unit 17 uses antenna element groups 15-4, 15-5, and 15-6 made of antenna elements in different directions (X, Y, Z). The respective transmission capacities are obtained from the received power and the correlation value for each antenna element of each measured antenna element group, and the switches 14-1 to 14-3 are switched by the switch switching control unit 21 according to the magnitude of the transmission capacity. Except for selecting an antenna element to be used for transmission, this is basically the same as the first or second embodiment described above.

D. Fourth Embodiment Next, a fourth embodiment of the present invention will be described.
FIG. 5 is a block diagram showing the configuration of the wireless communication apparatus according to the fourth embodiment. Note that portions corresponding to those in FIG. 4 are denoted by the same reference numerals and description thereof is omitted. In the fourth embodiment, as shown in FIG. 5, as a plurality of antenna element groups, an antenna element group 15-7, an antenna element group 15-8, and an antenna element group 15-9 each composed of antenna elements in different directions. Is provided. The antenna elements in the antenna element group 15-7 are arranged in the Z direction (Z1, Z2, Z3), and the antenna elements in the antenna element group 15-8 are in the X direction (X1, X2, X3), the antenna element group. The antenna elements 15-9 are arranged in the X, Y, and Z directions (X, Y, Z). The transmitters 12-1, 12-2, and 12-3 can be connected to any one of the respective antenna element groups 15-7 to 15-9 in a switchable manner.

  The antenna control operation in the fourth embodiment is basically the same except that the antenna element group 15-7, the antenna element group 15-8, and the antenna element group 15-9, each composed of antenna elements in different directions, are used. Furthermore, this is the same as the first or second embodiment described above.

  According to the first to fourth embodiments described above, it is possible to obtain a high transmission capacity even in a mobile communication environment where the SNR varies greatly depending on the location.

  In the first embodiment of the present invention, there are two types of antenna combinations that can be selected: the antenna 15-1 or the antenna 15-2 in FIG. Therefore, in the description of FIG. 2, two types of processing of Steps S1 to S5 and Steps S6 to S10 are separately performed. As a result, an alternative is performed in Step S11 and switching by the switch 14 is performed. However, in the third embodiment of the present invention, the total number of antenna combination patterns is 27 (3 × 3 × 3), and in the fourth embodiment, there are three antenna options. In this case, the processing corresponding to steps S1 to S5 and steps S6 to S10 is performed by the number of the combinations, or a part thereof, and the switch is selected so as to select the antenna that maximizes the transmission capacity. Switch.

  For example, when receiving a series of radio signals, the processes corresponding to steps S1 to S5 and steps S6 to S10 cannot be performed simultaneously. Therefore, for example, in the case of packet-based communication, when one wireless packet is received, processing corresponding to steps S1 to S5 is performed, and when the next wireless packet is received, steps S6 to S10 are performed. It is also possible to execute different processing for each series of reception processing, such as performing corresponding processing. In this case, the switch switching process may be performed by switching the switch so as to select the combination of antennas that gives the maximum transmission capacity from the acquired received power information and correlation value information.

  Or, in an environment with relatively small environmental fluctuations, all the processes corresponding to steps S1 to S5 and steps S6 to S10 are performed on all combinations of antennas that can be selected before the start of communication. The switch may be selected after learning. In this case, even if the processing corresponding to steps S11 to S13 is not performed every time, the result of the determination is once recorded on the memory table, and step S14 is performed by referring to this content. In addition, a process equivalent to the process described in FIG. 2 can be realized. In addition, when the environmental variation cannot be completely ignored, it is possible to reselect the optimum antenna periodically at a certain interval.

It is a block diagram which shows the structure of the radio | wireless communication apparatus by 1st Embodiment of this invention. 5 is a flowchart for explaining an antenna control operation of the wireless communication apparatus according to the first embodiment. It is a block diagram which shows the structure of the radio | wireless communication apparatus by 2nd Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus by 3rd Embodiment of this invention. It is a block diagram which shows the structure of the radio | wireless communication apparatus by this 4th Embodiment. It is a conceptual diagram which shows the difference in the transmission capacity of MIMO transmission at the time of changing a correlation value with respect to the transfer function matrix H when it is set as 2 elements of transmission antenna elements and 2 elements of receiving antenna elements by a prior art. It is a block diagram which shows the MIMO structure using orthogonal polarization by a prior art. In contrast to the result of FIG. 6, in a situation where the correlation is low, it is a conceptual diagram showing a difference in transmission capacity when it is assumed that the SNR is 3 dB lower than the situation where the correlation is high.

Explanation of symbols

11 Transmission signal generator 12-1, 12-2, 12-3 Transmitter 13-1, 13-2 Circulator 14, 14-1, 14-2, 14-3 Switch (antenna selection means)
15-1 to 15-9 Antenna element group (multiple antenna element groups)
16-1, 16-2 Receiver 17 Received power measuring unit (Received power measuring means)
18 Correlation value measurement unit (correlation value measurement means)
19 Transmission capacity table (transmission capacity acquisition means)
20 Transmission capacity reference section (Transmission capacity acquisition means)
21 Switch switching control unit (antenna selection means)

Claims (12)

A first antenna group configured by a plurality of antennas, and a MIMO channel configured by the first antenna group and a second antenna group configured by a plurality of antennas included in another wireless communication device; A wireless communication device for performing MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time,
The first antenna group includes a plurality of antenna element groups having at least two types of different characteristics,
Antenna selection means for selecting one of the plurality of antenna element groups as a transmission antenna based on a received signal power and a correlation value of a reception signal received by each of the plurality of antenna element groups; A wireless communication device. A first antenna group configured by a plurality of antennas, and a MIMO channel configured by the first antenna group and a second antenna group configured by a plurality of antennas included in another wireless communication device; A wireless communication device for performing MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time,
The first antenna group includes a plurality of antenna element groups having at least two types of different characteristics,
An antenna selection unit is provided that selects one of the plurality of antenna element groups as a transmission antenna element based on reception signal power of a reception signal received by each of the plurality of antenna element groups. Wireless communication device. Received power measuring means for measuring received signal power of a received signal received by each of the plurality of antenna element groups;
Correlation value measuring means for measuring a correlation value of a received signal received by each of the plurality of antenna element groups;
Transmission capacity acquiring means for acquiring the transmission capacity of each of the plurality of antenna element groups based on the received signal power measured by the received power measuring means and the correlation value measured by the correlation value measuring means; And
The antenna selection unit selects one of the plurality of antenna element groups as a transmission antenna based on the transmission capacity of each of the plurality of antenna element groups acquired by the transmission capacity acquisition unit. The wireless communication apparatus according to claim 1. Receiving power measuring means for measuring the received signal power of the received signal received by each of the plurality of antenna element groups,
3. The wireless communication according to claim 2, wherein the antenna selection unit selects one of the plurality of antenna element groups as a transmission antenna based on the reception signal power measured by the reception power measurement unit. apparatus.   The plurality of antenna element groups include an antenna element group including a plurality of antenna elements having vertical polarization and an antenna element group including a plurality of antenna elements having vertical polarization and horizontal polarization. The wireless communication apparatus according to claim 1 or 2.   The plurality of antenna element groups includes an antenna element group including a plurality of antenna elements having vertical polarization and an antenna element group including a plurality of antenna elements having +45 degrees and −45 degrees polarization. The wireless communication apparatus according to claim 1 or 2, characterized in that:   The wireless communication device according to claim 1 or 2, wherein the plurality of antenna element groups are configured by a plurality of antenna element groups each including a plurality of antenna elements orthogonal to three directions.   The antenna selecting means selects one of the plurality of antenna element groups as a transmission antenna based on a relationship between a threshold value determined by a correlation value acquired in advance from a communication situation and the signal reception power. The wireless communication apparatus according to claim 2, wherein:   The wireless communication apparatus according to claim 1 or 2, wherein the plurality of antenna element groups include a plurality of antenna element groups including a plurality of antenna elements orthogonal to two directions.   The radio communication apparatus according to claim 1 or 2, wherein the plurality of antenna element groups include a plurality of antenna element groups including a plurality of antenna elements having directivities in two or more different directions. A first antenna group configured by a plurality of antennas, and a MIMO channel configured by the first antenna group and a second antenna group configured by a plurality of antennas included in another wireless communication device; An antenna control method in a wireless communication apparatus for performing MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time,
The first antenna group includes a plurality of antenna element groups having at least two types of different characteristics,
Measuring received signal power of a received signal received by each of the plurality of antenna element groups;
Measuring a correlation value of a received signal received by each of the plurality of antenna element groups;
Obtaining a transmission capacity of each of the plurality of antenna element groups based on the received signal power and the correlation value;
Selecting one of the plurality of antenna element groups as a transmission antenna based on the transmission capacity of each of the plurality of antenna element groups. A first antenna group configured by a plurality of antennas, and a MIMO channel configured by the first antenna group and a second antenna group configured by a plurality of antennas included in another wireless communication device; An antenna control method in a wireless communication apparatus for performing MIMO communication by spatially multiplexing a plurality of signal systems at the same frequency channel and at the same time,
The first antenna group includes a plurality of antenna element groups having at least two types of different characteristics,
Measuring received signal power of a received signal received by each of the plurality of antenna element groups;
Selecting one of the plurality of antenna element groups as a transmitting antenna based on the received signal power measured by the received power measuring means.

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