Abstract: The present invention relates to a radio communication system comprising base stations and mobile stations and a method for controlling transmission power in the system where the base station is able to perform multi-point transmission for transmitting the same signal to a plurality of the mobile stations. In the present invention, the mobile station targeted for the multi-point transmission provides the base station of an increase request or a decrease request of the transmission power by respectively transmitting or not transmitting a predetermined signal to the base station.

Abstract: A radio communication system for carrying out communications between radio stations by modulating a plurality of signal sequences to be transmitted and received into at least one frequency channel assigned to each of a plurality of cells is formed by a channel mapping means for rearranging for each cell a plurality of frequency channels assigned with respect to each cell, and newly assigning particular frequency channels as a transmission and reception band of said signal sequences, and a bandwidth control means for controlling a bandwidth of said assigned frequency channel according to a propagation state of said assigned frequency channel.

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 communication control method used in a cellular mobile communication system in which each base station can radiate radio wave beams to a plurality of directions and each base station communicates with mobile stations by using the same frequency is provided in which the method includes the step of: controlling first timing at which a base station radiates a first radio wave beam such that the first timing is different from second timing at which another base station radiates a second radio wave beam which may cause interference with the first radio wave beam.

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: According to the present invention, a control station 5 determines a number of groups to which cells belong, based on interference between the cells. Preferably, the control station 5 determines the number of groups as a number smaller than the number of cells constituting a closed cluster. The control station 5 determines the groups to which the cells belong, so as to keep constant shortest distances between cells belonging to the same group. Then the control station 5 determines a frequency band to be assigned to a cell belonging to a determined group, in each of the group units, and assigns different frequency bands to the respective groups.

Abstract: The object of the present invention is to achieve smooth hand-over in the radio communication system with a hierarchical cell structure that executes data transmission using orthogonal carrier frequency bands. In the sending radio station to arrange sending symbols in a frequency axis and send signals using one or a plurality of carrier frequency bands, on detecting there having been received one or more carrier frequency band signals pertaining to a transmission system other than that of its own station (SO1), the symbol synchronization will be detected based on the received signal (SO2), and the signal to be sent, will be sent at the symbol sending timing derived based on the detected symbol synchronization (SO3).

Abstract: A mobile communication system capable of determining a communication path to implement fast communication by multihop connection. The mobile communication system includes a mobile station, at least one relay station, and a base station and implements packet transmission from the mobile station to the base station through a communication path with an intermediary of at least one relay station or through a communication path without an intermediary of a relay station. The mobile communication system is provided with a communication path determiner for determining a communication path with a largest communication speed or a communication path satisfying a required line quality, based on interference levels of respective signals received at a relay station constituting a communication path between the transmitting station and the receiving station, and at the base station.

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: The multi-hop communication system according to the present invention is configured by a radio control station 1 connected to a core network, and radio stations 21, 22, 31-33. The radio control station 1 has a control signal TX/RX unit 12 which transmits/receives the control signal, an information signal TX/RX unit 13 which transmits/receives the information signal, and a communication channel controller 15 which transmits a “usage notification” indicating usage of communication channels managed by the radio control station 1 to the radio stations 21, 22, 31-33 using the control signal. The radio station has a control signal TX/RX unit 42 which transmits/receives the control signal, and an information signal TX/RX unit 43 which transmits/receives the information signal.

Abstract: The present invention relates to a radio communication system comprising base stations and mobile stations and a method for controlling transmission power in the system where the base station is able to perform multi-point transmission for transmitting the same signal to a plurality of the mobile stations. In the present invention, the mobile station targeted for the multi-point transmission provides the base station of an increase request or a decrease request of the transmission power by respectively transmitting or not transmitting a predetermined signal to the base station.

Abstract: A destination station 3 in a wireless communication system for a multi-hop connection selects a transmission path having a minimum total of required transmission power values of respective stations on the transmission path among candidates of the transmission path from a source station 1 to the destination station 3 and transmits a pilot signal to the source station 1 and a relay station 2, the pilot signal including identification information about the respective stations on the selected transmission path and required transmission power values thereof. Thus, the source station 1 and the relay station 2, which have received this pilot signal, can determine the transmission path having the minimum total of the required transmission power values by use of the identification information included in the received pilot signal.

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: The object is to control interference in a permissible range by applying the CDMA system to signal collision in the conventional CSMA and TDMA base multihop systems and to relax the hidden terminal problem and others to enhance the throughput of the entire system by grouping of channel groups in multihop transmission and by control of transmission based on an interference level from another station. A multihop relay station calculates a desired signal level, for example, from an interference level at its own station of a packet sent from a mobile station, and notifies the mobile station of the desired signal level; and the mobile station calculates a transmission power amount of a packet from the desired signal level, determines whether the packet is transmissible to the station as a source of the desired signal level, on the basis of the transmission power amount, and transmits the packet by a power of the transmission power amount to the source station determined as a packet-transmissible station.

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: In a burst signal transmitting/receiving method with transmission availability control, a method is provided for transmitting each burst signal with the transmission unit length appropriate for the transmission path condition at the time. Radio transmission path condition between a transmitting station and a receiving station is measured. A period during which the burst signal is to be transmitted is then determined on the basis of the measured radio transmission path condition. Before transmitted, the length of the burst signal is adjusted such that it is accommodated in such period.

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