Patent ID: 7450853

Claim:
A communications system, comprising: a base station configured to output first digital in phase and quadrature phase (I/Q) signals; an optical connecting unit configured to convert the first digital I/Q signals into optical signals and output the converted optical signals through an optical cable; and an optical base station coupled to receive the optical signals through the optical cable and configured to convert the optical signals into second digital I/Q signals, and convert the second digital I/Q signals into first RF signals for transmission, wherein the optical base station comprises: an optical transceiver configured to convert the optical signals received through the optical cable into the second digital I/Q signals; a multiplexer/demultiplexer unit configured to demultiplex the second digital I/Q signals outputted from the optical transceiver; an up-converter configured to convert and filter output signals of the multiplexer/demultiplexer unit and output the first RF signals; a High Power Amplifier (HPA) configured to amplify the first RF signals outputted by the up-converter; and a duplexer configured to filter the amplifier first RF signals and provide the filtered output to an antenna, wherein the optical base station further comprises: a plurality of duplexers configured to remove a noise component of second RF signals collected by a corresponding plurality of antennas; a plurality of Low Noise Amplifiers (LNAs) configured to amplify the second RF signals outputted from the plurality of duplexers; and a plurality of down-converter units configured to band-pass filter, down-convert and analog to digital convert, the second RF signals outputted from the plurality of LNAs.