Optical fiber-based wireless systems and related components and methods are disclosed. The systems support radio frequency (RF) communications with clients over optical fiber, including Radio-over-Fiber (RoF) communications. The systems may be provided as part of an indoor distributed antenna system (IDAS) to provide wireless communication services to clients inside a building or other facility. The communications can be distributed between a head end unit (HEU) that receives carrier signals from one or more service or carrier providers and converts the signals to RoF signals for distribution over optical fibers to end points, which may be remote antenna units (RAUs). In one embodiment, calibration of communication downlinks and communication uplinks is performed to compensate for signal strength losses in the system.

Optical fiber-based distributed antenna systems, components, and related methods for calibration thereof

A transmitter comprising two or more light-emitting sections, e.g, LEDs, in a specified physical arrangement is installed in a real world object and each light-emitting section turns on/off in an on/off pattern representative of transmission data of specified bit length to transmit data. A receiver having a light-receiving section comprising a two-dimensional light-receiving face decodes the transmission data based on the received on/off pattern and recognizes spatial information on the object based on the on/off position on the two-dimensional light-receiving face. ID information, or the like, is thereby acquired from an object in the real world and, at the same time, the spatial position of the object can be recognized.

Data communication system, data transmitter and data receiver

A hybrid wireless optical and radio frequency (RF) communication link utilizes parallel free-space optical and RF paths for transmitting data and control and status information. The optical link provides the primary path for the data, and the RF link provides a concurrent or backup path for the network data, as well as a reliable and primary path for the control and status information. When atmospheric conditions degrade the optical link to the point at which optical data transmission fails, the hybrid communication link switches to the RF link to maintain availability of data communications. The switch may occur automatically, based on an assessment of the quality of the optical signal communicated through the optical path.

Hybrid wireless optical and radio frequency communication link

A network includes a plurality of antennas coupled to a plurality of base stations. The network can be optical or constructed with RF microwave links. The antennas and base stations are configured to transmit and receive digital signals representing cellular signals and the digital signals are exchanged over the network. A plurality of links couple the plurality of antennas and the plurality of base stations. At least one link of the plurality of links provides multiple transmission paths between at least a portion of the base stations and at least a portion of the antennas.

Method and apparatus for multiplexing in a wireless communication infrastructure

A system, and related methods and devices, is disclosed for increasing an output power of a frequency band in a distributed antenna system that includes at least one RXU module that is operatively coupled to at least one RAU module. A first group of the plurality of channels within a first frequency band may be allocated to the RAU module, and a second group of the plurality of the channels within the first frequency band may be allocated to the RXU module. The at least one RAU module may be configured to receive RF signals from the first group of the plurality of channels being used in the first frequency band, and the at least one RXU module may be configured to receive RF signals from the second group of the plurality of channels being used in the first frequency band. In this manner, the amount of composite power per channel is increased.

Systems, methods, and devices for increasing radio frequency (RF) power in distributed antenna systems

A central control station, which controls radio base stations connected thereto via radio links and optical fiber links, includes a demultiplexing unit which demultiplexes signals supplied from an upper-level station, signal conversion units which convert the respective demultiplexed signals into converted signals having a unified transmission format, and a distribution unit which distributes the converted signals to the radio links and the optical fiber links.

Radio base station system and central control station with unified transmission format

A wireless base station network system in which base stations arranged at a plurality of cells and a control station for controlling the base stations are connected through optical fibers by wavelength-division multiplexing transmissions. The base station is provided with a wavelength-variable transmitter for transmitting optical signals of a predetermined wavelength, and an optical coupler for multiplexing optical signals from the wavelength-variable transmitter for the wavelength-division multiplexing transmissions. The control station is provided with a plurality of optical receivers for receiving the divided and multiplexed wavelengths of the optical signals, and an optical coupler for branching the optical signals having been divided and multiplexed from the plurality of base stations, individually to the wavelengths. Where the wireless communication terminal to communicate with the base station moves to change its communicating base station, a new base station, to which the wireless communication terminal has moved, controls the wavelength of the wavelength variable transmitter and transmits the optical signal wavelength identical to that transmitted by the base station before the movement, to the control station.

Wireless base station network system, control station, base station switching method, signal processing method, and handover control method

A radio communication system comprises: a radio receiver including an interference canceller configured to generate a replica of a received signal and remove an interference signal from the received signal, and a frequency offset estimator configured to estimate a carrier frequency offset between a carrier frequency of the interference signal and a carrier frequency of a desired signal included in the received signal; and a radio transmitter including a frequency controller configured to adjust a carrier frequency of a transmitted desired signal to the carrier frequency of the interference signal based on the carrier frequency offset received from the radio receiver.

Radio communication system, radio station, and radio communication method

Multi-Hop Wireless Link System for New Generation Mobile Radio Access Networks

A reception side radio station has a notification signal generator 108 which transmits a notification signal for notifying information of a frequency of a radio link being used at the radio station, and a transmitter 111 which transmits information indicating a reception power level and its frequency as radio signal data. On the other hand, a transmission side radio station has a notification signal measurer 106 which measures a reception power level of the notification signal and detects the frequency notified by the signal, and a frequency band controller 109 which determines an assignable frequency band for a radio link between the transmission side radio station and the reception side radio station based on the radio signal data and the notification signal.

Yuji Aburakawa

Papers

Radio base station system and central control station with unified transmission format

Wireless base station network system, control station, base station switching method, signal processing method, and handover control method

Radio communication system, radio station, and radio communication method

Multi-Hop Wireless Link System for New Generation Mobile Radio Access Networks

Communication control method and communication control system