Abstract: An information transmission system for transmitting information from a sending apparatus to a receiving apparatus is provided. The information transmission system includes: a sending apparatus for modulating an information signal, generating a plurality of signals including an optical signal from the information signal which is modulated, and transmitting the plurality of signals via a plurality of routes; and a receiving apparatus for receiving the plurality of signals from the sending apparatus, diversity-combining the plurality of signals, and outputting the information signal, in which the plurality of signals are a plurality of optical signals or signals including a radio signal.

Abstract: 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.

Abstract: A radio receiver is provided with a beam-width-variable antenna that receives a radio signal and is capable of changing the beam-width; an interference canceler for removing interference waves from the received radio signal and outputting an interference-wave-removed signal; a measuring device for measuring reception quality of the received signal based on the interference-wave-removed signal; and a beam-width controller for controlling the beam-width of the beam-width-variable antenna based on the reception quality from the measuring device.

Abstract: When a signal is sent from a wireless base station 3-1, a wireless modem 10-1 converts the signal to a signal of a unified transmission form. The switch 11-1 switches the signal to one of wireless transceivers 12-1, 12-2 and the optical transceiver 13-1. The wireless transceiver 12-1 or 12-2 sends the signal to a control station 4 or a wireless base station 3—3 via a wireless circuit 20. The optical transceiver 13-1 converts the signal into an optical signal and sends the optical signal to a wireless base station 3-2 via an optical fiber circuit 30.

Abstract: A frequency band controlling part 107 determines a frequency band assignable to a transmission line according to the frequency, bandwidth, and the power of the interference wave at a base station 200 by means of a supplied control signal from a separating part 105. The frequency band controlling part 107 selects a frequency band for the transmission line and a frequency band for the reception line for the base station 200 according to this assignable frequency band contained in the control signal.

Abstract: 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.

Abstract: 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.

Abstract: A radio receiver is provided with a beam-width-variable antenna that receives a radio signal and is capable of changing the beam-width; an interference canceller for removing interference waves from the received radio signal and outputting an interference-wave-removed signal; a measuring device for measuring reception quality of the received signal based on the interference-wave-removed signal; and a beam-width controller for controlling the beam-width of the beam-width-variable antenna based on the reception quality from the measuring device.

Abstract: A frequency band controlling part 107 determines a frequency band assignable to a transmission line according to the frequency, bandwidth, and the power of the interference wave at a base station 200 by means of a supplied control signal from a separating part 105. The frequency band controlling part 107 selects a frequency band for the transmission line and a frequency band for the reception line for the base station 200 according to this assignable frequency band contained in the control signal.

Abstract: The present invention is a network system of radio base stations comprising base stations provided in a plurality of cells and a control station controlling the base stations, in which the base stations and the control station are connected by optical fibers using a wavelength multiplexing transmission method, wherein: the base station comprises a variable-wavelength transmitter for transmitting an optical signal having a predetermined wavelength, and an optical coupler for combining optical signals from the variable-wavelength transmitter in order to transmit the optical signals using the wavelength multiplexing transmission method, the control station comprises a plurality of optical receivers for receiving wavelengths of the optical signals transmitted using the wavelength multiplexing transmission method, and an optical coupler for splitting the wavelength-multiplexed optical signals transmitted from the base stations into the optical receivers by wavelength, and when the radio communication terminal comm

Abstract: An information transmission system for transmitting information from a sending apparatus to a receiving apparatus is provided. The information transmission system includes: a sending apparatus for modulating an information signal, generating a plurality of signals including an optical signal from the information signal which is modulated, and transmitting the plurality of signals via a plurality of routes; and a receiving apparatus for receiving the plurality of signals from the sending apparatus, diversity-combining the plurality of signals, and outputting the information signal, in which the plurality of signals are a plurality of optical signals or signals including a radio signal.

Abstract: In transmitting/receiving optical beams including optical signals via a space transmission path between an optical transmitting apparatus and an optical receiving apparatus, a degree of spread of the optical beam emitted from the optical transmitting apparatus to the-optical receiving apparatus is varied according to a predetermined condition.

Abstract: When a signal is sent from a wireless base station 3-1, a wireless modem 10-1 converts the signal to a signal of a unified transmission form. The switch 11-1 switches the signal to one of wireless transceivers 12-1, 12-2 and the optical transceiver 13-1. The wireless transceiver 12-1 or 12-2 sends the signal to a control station 4 or a wireless base station 3-3 via a wireless circuit 20. The optical transceiver 13-1 converts the signal into an optical signal and sends the optical signal to a wireless base station 3-2 via an optical fiber circuit 30.

Abstract: 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.