A transmitter, receiver and transceiver system that may be used for both transmitting and receiving modulated signals are disclosed. The system includes an Electrical-to-Optical (E2O) converter that receives a Radio Frequency (RF) signal and transmits an optical signal and/or an Optical-to-Optical (O2O) that performs a wavelength translation from one wavelength to another wavelength. The Electrical-to-Optical (E2O) converter includes a vapor cell that converts the RF signal to an optical signal.

An optical isolator system comprises an electrical-to-optical converter apparatus for receiving an input electrical signal from a system of an aircraft and converting the input electrical signal into an optical signal which is representative of the input electrical signal. The optical isolator system further comprises an optical-to-electrical converter apparatus for receiving the optical signal from the electrical-to-optical converter apparatus, for converting the received optical signal into an output electrical signal which is representative of the received optical signal, and for transmitting the output electrical signal to a portable server for the wireless distribution of content such as visual content, web content, video content, audio content, games, services, information and/or advertising content to clients in the aircraft. Associated methods are also described.

An operational environment is disclosed herein that includes a cryogenic environment and a signal source. The cryogenic environment includes a signal target, an optical link, signal converter devices, and an electrical link. Outside of the cryogenic environment, the signal source generates an electric signal. An electric-to-optical converter converts the electrical signal into an optical signal. The optical link delivers the optical signal into the cryogenic environment. Inside the cryogenic environment, an optical-to-electrical converter converts the optical signal back into an electrical signal. The optical-to-electrical converter transfers the electric signal to the signal target.

Grid of beams (GoB) adaptation in a wireless communications circuit, particularly for a wireless communications system (WCS), is disclosed. The wireless communications circuit may be provided in the WCS to provide radio frequency (RF) coverage in a wireless communications cell. In this regard, an antenna array is provided in the wireless communications circuit to radiate the GoB, which includes a number of RF beams corresponding to an RF communications signal(s), in the wireless communications cell. In examples discussed herein, the wireless communications circuit can be configured to detect a coverage condition change in the wireless communications cell and modify the GoB accordingly. By adapting the GoB to the coverage condition change, it may be possible to reduce processing overhead and improve resource usage, data throughput, and system adaptability of the wireless communications circuit, thus helping to optimize RF coverage in the wireless communications cell.

Provided are a light transmission device and a control method of same which can switch a processing sequence according to a vendor of an optical module to be mounted thereon. The light transmission device, which is provided with ports on which optical modules which transmit an optical signal are mounted, is additionally provided with: a storage means for holding a table in which processing sequences respectively corresponding to pieces of identification information about the optical modules are stored; and a control means for acquiring pieces of identification information about the mounted optical modules, determining, with reference to the table, a processing sequence corresponding to the identification information about the acquired optical module, and executing the determined processing sequence for the optical module.

Provided are a light transmission device and a control method of same which can switch a processing sequence according to a vendor of an optical module to be mounted thereon. The light transmission device, which is provided with ports on which optical modules which transmit an optical signal are mounted, is additionally provided with: a storage means for holding a table in which processing sequences respectively corresponding to pieces of identification information about the optical modules are stored; and a control means for acquiring pieces of identification information about the mounted optical modules, determining, with reference to the table, a processing sequence corresponding to the identification information about the acquired optical module, and executing the determined processing sequence for the optical module.

A communication system includes a central station device and a base station device. The central station device includes: a plurality of signal processing units, each generating an electrical signal of a wireless signal by performing signal processing corresponding to a wireless system; a conversion unit that generates an optical signal by performing intensity modulation on the electrical signal; and a signal processing control unit that controls the conversion unit to generate an optical signal in which a plurality of the electrical signals are multiplexed. The base station device includes: an electrical signal generation unit that receives the optical signal generated in the central station device via an optical transmission path and converts the received optical signal into a plurality of electrical signals; and a plurality of antenna devices, each wirelessly transmitting the wireless signal according to the electrical signal generated by the electrical signal generation unit.

A derivation method includes: a transmission step of transmitting, to a wireless terminal, a first radio-wave signal according to an optical signal with a first wavelength and a second radio-wave signal according to an optical signal with a second wavelength; a communication start time information acquisition step of acquiring information on a first communication start time and information on a second communication start time; a reception time information acquisition step of acquiring information on a first reception time and information on a second reception time; a transmission time period derivation step of deriving a first round trip time and deriving a second round trip time; and an optical fiber length derivation step of deriving an optical fiber length, based on the first round trip time, the second round trip time, a group velocity or a group delay time of the optical signal with the first wavelength, and a group velocity or a group delay time of the optical signal with the second wavelength.

A redundancy system for a distributed antenna system is provided. The system includes a first communication link, a second communication link, a first communication node and a second communication node. The first communication link traverses first path. The second communication link traverses a second path. The second path is spatially separated from the first path. The first communication node is communicatively coupled to transmit the same signal through both the first communication link and the second communication link. The second communication node has a receiver system that is communicatively coupled to receive the signals transmitted through the first and second communication links. The receiver system is configured to synchronize delay and phase differences between the received signals and then combine the signals together to generate a single output.

A method of generating and processing an analog transport signal for a fronthaul of a radio access network, where the analog signal carries a plurality of channels. The analog signal is generated by defining frequency bands of a fixed width within the analog transport signal. Channels are arranged within each frequency band so that, if the analog transport signal is sampled at a frequency equal to twice the fixed width, each channel of a frequency band has the same intermediate frequency as a corresponding channel of at least one other frequency band. A method of demultiplexing the analog transport signal for execution by a receiver is also proposed.