초록 ▼

A microcellular communications network includes a plurality of base station units and corresponding antenna units. The base station units are housed in a common location. Each includes either conventional transmitters and receivers or all digital transmitter and receiver equipment, and interface cir

A microcellular communications network includes a plurality of base station units and corresponding antenna units. The base station units are housed in a common location. Each includes either conventional transmitters and receivers or all digital transmitter and receiver equipment, and interface circuitry to a mobile telecommunications switching office. The microcell traffic output is applied to a frame generator/multiplexer. The output of the frame generator/multiplexer is applied to a digitally modulated laser. The laser output is conveyed by fiber to a remote antenna unit, which demultiplexes the microcell traffic signal and applies it to a digital-to-analog converter. The output of the digital-to-analog converter is applied to a power amplifier, which in turn is connected to a main antenna. RF signals from the mobile units are received at both a main and a diversity antenna. The received signals are filtered, digitized, multiplexed together and transmitted over the optical fiber back to the base station. The strongest signal is selected for use.

대표청구항 ▼

A microcellular communications system, comprising: a plurality of commonly located microcell base station units each connected by a fiber path to a plurality of corresponding antenna units for transmission of microcell traffic, each base station unit including: RF transmitters and receivers, one for

A microcellular communications system, comprising: a plurality of commonly located microcell base station units each connected by a fiber path to a plurality of corresponding antenna units for transmission of microcell traffic, each base station unit including: RF transmitters and receivers, one for each channel assigned to the microcell; combiner means for combining an analog RF signal output from the transmitters; analog-to-digital means for converting the single combined analog signal to a digitized stream of samples; framing means for framing the digitized stream; means for receiving the framed stream and for digitally modulating a laser signal with the framed stream for application to the fiber path for transmission to the corresponding antenna unit; and optical receiver means for detecting the framed stream modulated on the fiber path, wherein each antenna unit further includes: demultiplexer means for receiving the framed stream and extracting the digitized stream; digital-to-analog means for receiving the digitized stream and reconstructing the analog RF signal output; amplifier means for amplifying the reconstructed analog signal; antenna means for receiving the amplified signal and broadcasting it into a microcell area; means for receiving an RF microcell traffic signal received at the antenna unit; analog-to-digital converter means for converting the received RF microcell traffic signal to a digitized RF signal data stream; framer means for framing the digitized RF signal data stream; and laser means for receiving the framed RF signal data stream and for digitally modulating a laser signal with the framed RF signal data stream for application to the fiber path for transmission to the corresponding base station unit; wherein each base station unit further includes: demultiplexer means for receiving the framed RF signal data stream from the antenna unit and extracting the digitized RF signal data stream; and digital-to-analog converter means for receiving the digitized RF signal data stream and reconstructing the analog RF microcell traffic signal representing all channels assigned to the microcell, the RF microcell traffic signal being applied to the receivers.