A device comprising a ground station device (100c; 100d), wherein the ground station device (100c; 100d) is configured to constitute a base station apparatus (1c; 1d) of a wireless communication system when being coupled via an optical fiber constituting an optical transmission path with a plurality of ground antenna devices (200c-1 to 200c-N) such that the ground station device (100c; 100d) is configured to: transmit a multiplexed optical signal to the plurality of ground antenna devices (200c-1 to 200c-N) via the optical transmission path; wherein the ground station device (100c; 100d) comprises: a transmission electrical signal generating section configured to generate an analog electrical signal; a reference clock signal generating section configured to generate a reference clock signal; and an electrical-optical converting section configured to: perform electrical-optical conversion on the analog electrical signal and the reference clock signal to generate optical signals, perform wavelength division multiplexing on the optical signals obtained through the electrical-optical conversion to generate the multiplexed optical signal, output the multiplexed optical signal to the optical transmission path, receive a further multiplexed optical signal from each of the ground antenna devices (200c-1 to 200c-N), the further multiplexed optical signal being obtained by the ground antenna device through electrical-optical conversion of analog electrical signals received from the mobile station and through wavelength division multiplexing of the electrical-optical converted analog electrical signals, and being output by the ground antenna device to the optical transmission path, demultiplex the received further multiplexed optical signal into demultiplexed optical signals, and perform optical-electrical conversion on the demultiplexed optical signals to obtain the analog electrical signals; and a wireless demodulating section (120; 120d; 120, 125-1, 125-2) configured to demodulate the analog electrical signals obtained through the optical-electrical conversion at the electrical-optical converting section characterized in that the wireless demodulating section (120d; 120, 125-1, 125-2) is configured to: receive, from the electrical-optical converting section, the analog electrical signals received by the plurality of ground antenna devices from the mobile station, and perform diversity demodulation on the received analog electrical signals. a transmission electrical signal generating section configured to generate an analog electrical signal; a reference clock signal generating section configured to generate a reference clock signal; and an electrical-optical converting section configured to: perform electrical-optical conversion on the analog electrical signal and the reference clock signal to generate optical signals, perform wavelength division multiplexing on the optical signals obtained through the electrical-optical conversion to generate the multiplexed optical signal, output the multiplexed optical signal to the optical transmission path, receive a further multiplexed optical signal from each of the ground antenna devices (200c-1 to 200c-N), the further multiplexed optical signal being obtained by the ground antenna device through electrical-optical conversion of analog electrical signals received from the mobile station and through wavelength division multiplexing of the electrical-optical converted analog electrical signals, and being output by the ground antenna device to the optical transmission path, demultiplex the received further multiplexed optical signal into demultiplexed optical signals, and perform optical-electrical conversion on the demultiplexed optical signals to obtain the analog electrical signals; and a wireless demodulating section (120; 120d; 120, 125-1, 125-2) configured to demodulate the analog electrical signals obtained through the optical-electrical conversion at the electrical-optical converting section characterized in that the wireless demodulating section (120d; 120, 125-1, 125-2) is configured to: receive, from the electrical-optical converting section, the analog electrical signals received by the plurality of ground antenna devices from the mobile station, and perform diversity demodulation on the received analog electrical signals.