A test device tests conditions associated with a fronthaul in an Open Radio Access Network (O-RAN). The test device can field test an O-RAN radio unit (O-RU) installed at a cell site by emulating an O-RAN distributed unit (O-DU) in the O-RAN connected to the O-RU via the fronthaul of the O-RAN. The testing includes testing connectivity of the O-RU to the fronthaul. The testing includes executing managing plane (M-plane) and synchronization plane (S-plane) messaging to test management session establishment, device setting testing, and master clock synchronization testing. Additionally, optical insertion loss in the fronthaul and frequency and power of signals transmitted from the O-RU can be tested.

An optical communication device includes a WDM optical transmission reception unit that receives an optical signal and converts the optical signal to an electric signal, a MUX/DEMUX unit that converts the electric signal obtained by the conversion to a plurality of electric signals, signal detection units, a switch unit that changes paths, client IF units, and a control unit. A first signal detection unit among the signal detection units detects a first electric signal among the plurality of electric signals. When the first electric signal is a signal to be processed based on a first communication standard, the control unit controls the switch unit so that the first electric signal is inputted to a client IF unit that executes a process based on the first communication standard among the client IF units.

Provided is a distributed antenna system (DAS) for multi-frequency band and multi-carrier equipped with an open radio access network (O-RAN) remote unit (RU) according to an O-RAN technology standard for building a next-generation radio infrastructure. To this end, the DAS for multi-carrier and multi-frequency band based on an O-RAN standard includes an O-RAN RU connected to a fronthaul network according to an O-RAN split option specification of base station transceiver systems (BTSs), and including a plurality of O-RAN RUs to accommodate a plurality of carriers and a plurality of frequency bands; and a channel combiner to which outputs of the plurality of O-RAN RUs are combined.

There is described a reconfigurable array for facilitating dynamic combination and distribution of RF signals. The reconfigurable array comprises: (a) a number, N.sub.i, of input devices for generating or supplying RF input signals; (b) a number, N.sub.o, of output devices for analysing or forwarding RF output signals; (c) an optical switch matrix comprising a number, N.sub.p, of ports, wherein each of the ports is an optical input or an optical output, wherein each input device is coupled to a respective port of the optical switch matrix at an optical input, wherein each output device is coupled to a respective port of the optical switch matrix at an optical output, and wherein the optical switch matrix is configurable to enable optical connection of any optical input to any optical output; and (d) a plurality of multi-port devices that each have multiple uncommon ports which couple to a single common port, wherein each port of each multi-port device is coupled to a respective port of the optical switch matrix, and wherein each multi-port device enables either fan-in of optical signals from the uncommon ports to the common port or fan-out of optical signals from the common port to the uncommon ports depending on the configuration of the reconfigurable array. The plurality of multi-port devices include at least one M:1 multi-port device, where M is a predetermined maximum number of RF signals for the reconfigurable array to fan-in or fan-out, where M≤N.sub.i and M≤N.sub.o.

An optical medium, such as fiber, is tapped to provide an antenna port wherever radio service coverage is desired. Each antenna port is a bi-directional remote unit that receives a digital optical signal from a host unit and transforms the signal to a radio frequency signal for transmission by the remote unit. The remote unit receives radio frequency signals that are converted to digital signals and summed with signals from other remote units and converted to an optical signal for transmission to the host unit.

A radio communication system for duplex communication comprising an optical carrier generator for generating optical carrier signals, a local oscillator (LO) for generating an electrical signal in a radio communication band, an information signal source, electro-optic modulators driven directly at an input electrical port by said information signal and said LO signal to modulate a portion of said optical carrier signal to form a modulated portion being an optical band information signal for transmission over an optical link; and a photodetector remote from said electro-optic modulators for receiving said transmitted optical band information signal from said optical link, and directly generating an electrical signal that is up-converted for radio transmission, or down-converted to a baseband frequency.

Dynamically-switchable optical cables are described. One aspect includes a first terminal and a second terminal, each including a USB/Thunderbolt high-speed electrical interface. Each terminal may include a USB/Thunderbolt signal analysis unit configured to receive one or more USB/Thunderbolt low-speed signals, analyze the USB/Thunderbolt low-speed signals, and determine if the associated terminal is connected to one of a USB/Thunderbolt signal source or a USB/Thunderbolt signal sink. Each terminal may include a signal transmitting unit electrically connected to the respective USB/Thunderbolt high-speed electrical interface, and a signal receiving unit electrically connected to the respective USB/Thunderbolt high-speed electrical interface. The optical cable may include a first optical communication channel connecting an output of the first signal transmitting unit to an input of the second signal receiving unit, and a second optical communication channel connecting an output of the second signal transmitting unit to an input of the first signal receiving unit.

An accommodation station transmission unit modulates light to generate an optical signal based on an RF signal and outputs the generated optical signal, a base station transmission unit obtains the optical signal from an input port, demultiplexes the obtained optical signal for each wavelength, outputs the demultiplexed optical signals from output ports of corresponding wavelengths from among a plurality of output ports allocated to each of the wavelengths of the light, and demodulates the RF signal by converting the optical signals output by the output ports into electrical signals, a plurality of transmission antennas emit the demodulated RF signal, and a reflect array or a transmit array receives the RF signal emitted by each of the transmission antennas and forms a transmission beam in a different direction for each position of the transmission antenna that is a transmission source of the RF signal for each RF signal.

A distributed antenna system comprises: one or more access units configured to receive multiple downlink radio frequency signal sets, and further configured to convert the multiple downlink radio frequency signal sets into multiple downlink optical signal sets; a first wavelength division multiplexing unit configured to multiplex the multiple downlink optical signal sets to generate a first wavelength division multiplexing optical signals; a first wavelength division demultiplexing unit configured to demultiplex the first wavelength division multiplexing optical signals to obtain the multiple downlink optical signal sets; a first optical fiber, coupled between the first wavelength division multiplexing unit and the first wavelength division demultiplexing unit, and configured to transmit the first wavelength division multiplexing optical signal; and multiple first remote units coupled to the first wavelength division multiplexing unit, and configured to convert the multiple downlink optical signal sets into the multiple downlink radio frequency signal sets for transmission.

A distributed antenna system comprises a first access unit and a remote unit, wherein the first access unit and the remote unit are coupled via an analog optical fiber, and the first access unit comprises: a first port configured to receive a first downlink analog radio frequency signal; a first analog-to-digital conversion unit configured to perform analog-to-digital conversion on the first downlink analog radio frequency signal to generate a first downlink digital signal; a first digital processing unit configured to perform digital signal processing on the first downlink digital signal to generate a second downlink digital signal; a first digital-to-analog conversion unit configured to perform digital-to-analog conversion on the second downlink digital signal to generate a second downlink analog radio frequency signal; and an analog optical module configured to perform electro-optical conversion on the second downlink analog radio frequency signal to generate a first downlink analog optical signal.