Wireless communication apparatus, wireless communication system and wireless communication method

1 . A radio communication device that performs communication with a terminal-side communication device having an antenna using an analog signal for transmitting information by a waveform of an amplitude or a phase of light to receive a signal received by the antenna and transmit a signal radiated by the antenna, the terminal-side communication device and the radio communication device being included in a radio communication system that performs radio communication with a communication target terminal via the antenna using time division duplex (TDD), the radio communication device comprising:

an uplink delay adjuster is located in a first path and is configured to adjust a delay caused by propagation of an uplink signal that is a signal flowing from the terminal to the radio communication device via the antenna, where the uplink signal propagates along the first path using wavelength division multiplexing; and

a downlink delay adjuster is located in a second path and is configured to adjust a delay caused by propagation of a downlink signal that is a signal flowing from the radio communication device to the terminal via the antenna, where the downlink signal propagates along the second path using wavelength division multiplexing, such that the first path and the second path are distinct from each other and do not overlap.

2 . The radio communication device according to claim 1 , wherein a time of the delay adjusted by the uplink delay adjuster is a time based on a delay time occurring in a section in which the uplink signal propagates from the antenna to the radio communication device.

3 . The radio communication device according to claim 1 , wherein a time of the delay adjusted by the downlink delay adjuster is a time based on a delay time occurring in a section in which the downlink signal propagates from the radio communication device to the antenna.

4 . The radio communication device according to claim 1 , wherein the uplink signal whose delay is to be adjusted by the uplink delay adjuster is converted from analog to digital prior to the uplink delay adjuster.

5 . The radio communication device according to claim 1 , wherein the downlink signal whose delay is to be adjusted by the downlink delay adjuster is converted from analog to digital prior to the downlink delay adjuster a digital signal.

6 . A radio communication system that performs communication with a communication target terminal using time division duplex (TDD), the radio communication system comprising:

a terminal-side communication device having an antenna; and

a radio communication device that performs communication with the terminal-side communication device using an analog signal for transmitting information by a waveform of an amplitude or a phase of light to receive a signal received by the antenna and transmit a signal radiated by the antenna,

wherein the radio communication device includes

an uplink delay adjuster is located in a first path and is configured to adjust a delay caused by propagation of an uplink signal that is a signal flowing from the terminal to the radio communication device via the antenna, where the uplink signal propagates along the first path using wavelength division multiplexing, and

a downlink delay adjuster is located in a second path and is configured to adjust a delay caused by propagation of a downlink signal that is a signal flowing from the radio communication device to the terminal via the antenna, where the downlink signal propagates along the second path using wavelength division multiplexing, such that the first path and the second path are distinct from each other and do not overlap.

7 . A radio communication method provided by a radio communication system including a terminal-side communication device having an antenna and a radio communication device that performs communication with the terminal-side communication device using an analog signal for transmitting information by a waveform of an amplitude or a phase of light to receive a signal received by the antenna and transmit a signal radiated by the antenna, the radio communication device including an uplink delay adjuster is located in a first path and is configured to adjust a delay caused by propagation of an uplink signal that is a signal flowing from the terminal to the radio communication device via the antenna, where the uplink signal propagates along the first path using wavelength division multiplexing, and a downlink delay adjuster is located in a second path and is configured to adjust a delay caused by propagation of a downlink signal that is a signal flowing from the radio communication device to the terminal via the antenna, where the downlink signal propagates along the second path using wavelength division multiplexing, such that the first path and the second path are distinct from each other and do not overlap, the radio communication method comprising:

switching an operation of the antenna from a reception operation of receiving a signal transmitted by the terminal to a radiation operation of radiating a signal; and

switching the operation of the antenna from the radiation operation to the reception operation.