Radio Communication System and Method

1. A radio communication system comprising: a radio; an antenna side device positioned external to the radio; and a transmission line connecting the radio to the antenna side device and supplying an electric power voltage to the antenna side device, wherein the radio outputs a transmission signal to the antenna side device through the transmission line by superposing the transmission signal on the electric power voltage, the antenna side device outputs the transmission signal as a radio wave, and the radio outputs a control signal to the antenna side device through the transmission line by superposing the control signal on the electric power voltage during a time other than when the radio outputs the transmission signal through the same transmission line to the antenna side device.

2. The radio communication system of claim 1 , wherein the antenna side device outputs a reception signal to the radio through the transmission line that is indicative of a received radio wave, during a time when the antenna side device does not receive the transmission signal or the control signal from the radio, the antenna side device outputs a feedback signal that notifies a state of the antenna side device to the radio through the transmission line, and the control signal is determined based on the feedback signal.

3. The radio communication system of claim 2 , wherein the antenna side device includes a temperature detection circuit and a transmission amplifier with a variable gain, the feedback signal indicates a detected temperature from the temperature detection circuit, and the control signal includes a gain control signal that controls a gain of the transmission amplifier.

4. The radio communication system of claim 1 , wherein after outputting the control signal to the antenna side device, which includes a transmission mode signal for a switching of the antenna side device to a transmission mode, the radio outputs the transmission signal to the antenna side device at a transmission start timing that is determined based on a required switch time for the switching of the antenna side device to the transmission mode.

5. The radio communication system of claim 1 , wherein an Inter Frame Space (IFS) time is a time period after a busy-to-idle state transition of a communication channel, a back-off time is a time period subsequent to the IFS time, and based on carrier sensing of the communication channel, the radio outputs the control signal during the IFS time or the back-off time.

6. The radio communication system of claim 5 , wherein the carrier sensing of the communication channel is repeatedly performed at a preset timing.

7. A communication radio comprising: a radio section; an antenna side device positioned external to the radio section; and a transmission line connecting the radio section to the antenna side device and supplying an electric power to the antenna side device, wherein the radio section outputs a transmission signal to the antenna side device through the transmission line by superposing the transmission signal on a power voltage, and the antenna side device outputs the transmission signal as a radio wave, and the radio section outputs a control signal to the antenna side device through the transmission line by superposing the control signal on the power voltage during a time when the radio section does not output the transmission signal to the antenna side device.

8. A communication antenna comprising: a radio section; an antenna section positioned external to the radio section; and a transmission line connecting the radio section to the antenna section and supplying an electric power to the antenna section, wherein the radio section outputs a transmission signal to the antenna section through the transmission line by superposing the transmission signal on a power voltage, and the antenna section outputs the transmission signal as a radio wave, and the radio section outputs a control signal to the antenna section through the transmission line by superposing the control signal on the power voltage during a time when the radio section does not output the transmission signal to the antenna section.

9. A method for communicating using a radio communication system, the radio communication system includes a radio, an antenna side device that is positioned external to the radio, and a transmission line that connects the radio to the antenna side device and supplies an electric power to the antenna side device, the method comprising: superposing a transmission signal on a power voltage; outputting the transmission signal from the radio to the antenna side device through the transmission line as a radio wave; superposing a control signal on the power voltage; and outputting the control signal from the radio to the antenna side device through the transmission line when the radio does not output the transmission signal to the antenna side device.

10. The method for communicating using a radio communication system of claim 9 , further comprising: outputting a reception signal, which is indicative of a received radio wave from the antenna side device, to the radio through the transmission line; and outputting a feedback signal that notifies a state of the antenna side device from the antenna side device to the radio through the transmission line during a time when the antenna side device does not receive the transmission signal or the control signal from the radio.

11. The method for communicating using a radio communication system of claim 9 , wherein outputting the transmission signal from the radio to the antenna side device is started at a transmission start timing that is determined based on a required switch time for switching of the antenna side device to the transmission mode after outputting the control signal from the radio to the antenna side device, which includes a transmission mode signal for the switching of the antenna side device to the transmission mode.