A divider/combiner unit combines RF signals, then converts the combined signal
into an optical signal and sends it over an optical fiber. N radio access units
each convert the optical signal received from the optical fiber into an RF signal
and transmits it from an antenna, and each radio access unit converts an RF signal
received by the antenna into an optical signal and sends it over an optical fiber
to the divider/combiner unit. The divider/combiner unit converts the received optical
signal into RF signals and outputs them. This system is operated as plurality of
communication systems in common to them in correspondence to a plurality of input/output
terminals of the divider/combiner unit.