Radio communication apparatus, radio communication method, and non-transitory computer readable medium storing radio communication control program

1. A radio communication apparatus including an antenna set including a plurality of antennas and executing spatial-multiplexing based communication, comprising:

an antenna selection unit that selects from the antennas a combination of antennas whose quantity is equal to or less than a quantity of counterpart antennas to be communicated, as a combination of antennas to be used in spatial-multiplexing based communication;

a signal processing unit that executes signal processing for communication using the combination of antennas selected by the antenna selection unit;

an antenna configuration specifying unit that specifies a physical configuration of the plurality of antennas; and

a communication environment change detecting unit that detects a time-dependent change in a predetermined amount of variation in communication environment of the radio communication apparatus,

wherein the antenna selection unit selects the combination of antennas to be used based on the configuration specified by the antenna configuration specifying unit, and varies a period of changing a combination of antennas to be selected, depending on whether the time-dependent change in the amount of variation detected by the communication environment change detecting unit is equal to or less than a predetermined reference value.

2. The radio communication apparatus according to claim 1 , wherein the antenna configuration specifying unit specifies a physical inter-antenna distance as the physical configuration of the plurality of antennas, and

the antenna selection unit selects a combination of antennas which maximizes the physical inter-antenna distance specified by the antenna configuration specifying unit.

3. The radio communication apparatus according to claim 1 , wherein the antenna configuration specifying unit specifies a polarization direction of a radio signal to be transmitted/received by each antenna, and

the antenna selection unit selects a combination of antennas with different polarization directions specified by the antenna configuration specifying unit.

4. The radio communication apparatus according to claim 1 , wherein

the signal processing unit includes a plurality of signal processing circuits that process signals to be transmitted/received in association with the plurality of antennas included in the antenna set, and

power supply to one of the plurality of signal processing circuits which is not used is stopped based on the combination of antennas selected by the antenna selection unit.

5. The radio communication apparatus according to claim 1 , wherein

the signal processing unit includes a plurality of signal processing circuits that process signals to be transmitted/received in association with the plurality of antennas included in the antenna set, and

a setting value for carrying out communication with the antennas to be communicated or another antenna to be communicated is acquired by using an antenna which is not selected by the antenna selection unit and a signal processing circuit which is associated with the antenna.

6. The radio communication apparatus according to claim 1 , wherein the antenna set includes:

a first antenna set including a plurality of first antennas in which polarization directions of adjacent antennas are orthogonal to each other; and

a second antenna set including a plurality of second antennas in which polarization directions of adjacent antennas are orthogonal to each other.

7. The radio communication apparatus according to claim 6 , wherein

the first antenna set or the second antenna set is configured to be dismountable from the radio communication apparatus, and

wherein the radio communication apparatus further comprises a mount detection unit that detects if the first antenna set or the second antenna set is mounted to the radio communication apparatus.

8. The radio communication apparatus according to claim 1 , wherein

the antenna set includes:

a first antenna set including a plurality of first antennas, which make polarization directions of signals to be transmitted/received identical to each other; and

a second antenna set including a plurality of second antennas, which make polarization directions of signals to be transmitted/received identical to each other, and

the polarization direction of the signals to be transmitted/received by the plurality of first antennas is orthogonal to the polarization direction of the signals to be transmitted/received by the plurality of second antennas.

9. The radio communication apparatus according to claim 8 , wherein

the first antenna set or the second antenna set is configured to be dismountable from the radio communication apparatus, and

wherein the radio communication apparatus further comprises a mount detection unit that detects if the first antenna set or the second antenna set is mounted to the radio communication apparatus.

10. The radio communication apparatus according to claim 1 , wherein the antenna selection unit selects a combination of antennas in such a way as to always transmit/receive a signal having a certain polarization direction.

11. A radio communication apparatus including an antenna set including a plurality of antennas and executing spatial-multiplexing based communication, comprising:

antenna selection means that selects from the antennas a combination of antennas whose quantity is equal to or less than a quantity of counterpart antennas to be communicated, as a combination of antennas to be used in spatial-multiplexing based communication;

signal processing means that executes signal processing for communication using the combination of antennas selected by the antenna selection means;

antenna configuration specifying means that specifies a physical configuration of the plurality of antennas; and

communication environment change detecting means that detects a time-dependent change in a predetermined amount of variation in communication environment of the radio communication apparatus,

wherein the antenna selection means selects the combination of antennas to be used based on the configuration specified by the antenna configuration specifying means, and varies a period of changing a combination of antennas to be selected, depending on whether the time-dependent change in the amount of variation detected by the communication environment change detecting means is equal to or less than a predetermined reference value.

12. A radio communication method of executing spatial-multiplexing based communication using an antenna set including a plurality of antennas, comprising:

an antenna selection step of selecting from the antennas a combination of antennas whose quantity is equal to or less than a quantity of counterpart antennas to be communicated as a combination of antennas to be used in spatial-multiplexing based communication;

a signal processing step of executing signal processing for communication using the combination of antennas selected in the antenna selection step;

an antenna configuration specifying step of specifying a physical configuration of the plurality of antennas; and

a communication environment change detecting step of detecting a time-dependent change in a predetermined amount of variation in radio communication environment,

the antenna selection step selecting the combination of antennas to be used based on the configuration specified in the antenna configuration specifying step, and varying a period of changing a combination of antennas to be selected, depending on whether the time-dependent change in the amount of variation detected in the communication environment change detecting step is equal to or less than a predetermined reference value.

13. A non-transitory computer readable medium storing a program allowing a computer that controls a radio communication apparatus which executes spatial-multiplexing based communication using an antenna set including a plurality of antennas, to function as:

an antenna configuration specifying unit that specifies a physical configuration of the plurality of antennas;

an antenna selection unit that selects from the antennas a combination of antennas whose quantity is equal to or less than a quantity of counterpart antennas to be communicated, as a combination of antennas to be used in spatial-multiplexing based communication, based on the configuration specified by the antenna configuration specifying unit;

a signal processing unit that executes signal processing for communication using the combination of antennas selected by the antenna selection unit; and

a communication environment change detecting unit that detects a time-dependent change in a predetermined amount of variation in communication environment of the radio communication apparatus,

wherein the antenna selection unit varies a period of changing a combination of antennas to be selected, depending on whether the time-dependent change in the amount of variation detected by the communication environment change detecting unit is equal to or less than a predetermined reference value.