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: A controller in a transceiver for radio communications in which the same frequency is shared between multiple communications systems is disclosed that includes: a cyclic autocorrelation value calculation part configured to calculate the cyclic autocorrelation value of a first one of the communications systems from a received signal; and a data transmission authorization part configured to determine whether to authorize data transmission in a second one of the communications systems based on the calculated cyclic autocorrelation value of the first one of the communications systems.

Abstract: A transmitter comprises a frequency utilization status detector configured to detect the utilization status of an allocated frequency band based on a received signal, a symbol placement determination unit configured to determine placement of pilot symbols based on the detected status of frequency utilization, and a symbol placement unit configured to place the pilot symbols according to the determined symbol placement.

Abstract: A communication node that relays signals between a source node and a destination node includes (a) a first unitary matrix calculation unit configured to calculate a first unitary matrix based on a first channel between the source node and the relay node, (b) a second unitary matrix calculation unit configured to calculate a second unitary matrix based on a second channel between the relay node and the destination node, (c) a transformation matrix estimation unit configured to estimate a transformation matrix based on a triangular matrix derived from QR decomposition of the first and/or second channel matrix, (d) a relaying signal generator configured to generates a relaying signal by multiplying a received signal by at least one of the first unitary matrix, the second unitary matrix, and the transformation matrix, and (e) a transmission unit configured to transmit the relaying signal to the destination node.

Abstract: A radio transmitter adopting the OFDM scheme is disclosed. The radio transmitter includes an amplitude measuring part for measuring the amplitude of a transmission signal on which inverse Fourier transform has been performed; a power control part for outputting, based on the result of the measurement, control signals each for adjusting the amplitude of a signal on which inverse Fourier transform has not been performed, each signal corresponding to one of plural sub-carriers; and multiple multiplying parts each for multiplying the amplitude of the signal by a multiplying number indicated by the control signal. The power control part outputs the control signal based on a product of a signal pf(n) obtained by performing Fourier transform on an output of the amplitude measuring part and the signal sf(n).

Abstract: A communication node relays a transmission signal transmitted from a desired source node to a target destination node among multiple source nodes and multiple destination nodes. The communication node includes a first unitary matrix estimation unit that estimates a first unitary matrix by performing singular value decomposition involving one or more channel matrices between the relay node and the source nodes other than the desired source node; a second unitary matrix estimation unit that estimates a second unitary matrix by performing singular value decomposition involving one or more channel matrices between the relay node and the destination nodes other than the target destination node; and a transmission unit configured to transmit a relaying signal generated by multiplying a received signal by the first and second unitary matrices toward the target destination node.

Abstract: A prohibiting-signal transmitting apparatus for use in a combined system such that there is at least a partial overlap between bands allocated to an old communications system and bands allocated to a new communications system is disclosed. The apparatus includes a unit which monitors for a band-in-use, over which communications are actually being conducted, out of the bands allocated to the old communications system; a unit which generates a prohibiting signal indicating that the band-in-use should not be used in the new communications system; and a unit which transmits the prohibiting signal to a communications apparatus of the new communications system.

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, and transmits the packet to the source station determined as a packet-transmissible station.

Abstract: A disclosed base station is used in a first wireless communication system using a first frequency band that is the same as or adjacent to a second frequency band used by a second wireless communication system, and includes a propagation loss estimation unit configured to estimate propagation loss of a signal in the first frequency band when the signal arrives at a receiving device of the second wireless communication system; a frequency difference calculation unit configured to calculate a frequency difference between the first frequency band and the second frequency band; a maximum transmission power determining unit configured to determine maximum transmission power based on the estimated propagation loss and the calculated frequency difference; and a transmission control unit configured to transmit a signal with transmission power less than or equal to the maximum transmission power determined by the maximum transmission power determining unit.

Abstract: A transmitter used in the multiband environment includes a frequency allocation unit (106) configured to select and allocate a frequency band that satisfies a user QoS from among multiple separate frequency bands currently available for the user, a parameter determination unit (111) configured to determine a transmission parameter required for signal transmission based on the allocated frequency band, and a multi-user scheduling control unit (110) configured to determine a transmission schedule for multiple users taking into account the frequency bands allocated to the multiple users.

Abstract: A receiver comprises multiple receiving antennas configured to receive bitstreams transmitted from multiple transmission antennas; a bitstream candidate estimator configured to estimate a prescribed number of bitstream candidates among possible combinations of the received bitstreams and to calculate reliability information for each of the candidates; a bit-based estimator configured to produce a bit-based estimation result for each bit of the transmitted bitstreams based on the estimated candidates and the associated reliability information, the bit-based estimation result being adjusted by an adjusting criterion determined by the reliability information; and a decoder configured to decode the transmitted bitstreams based on the adjusted bit-based estimation result.

Abstract: The present invention has an object of providing a transmitter apparatus, a mobile communication system, a base station and a communication enable signal transmitter unit, which can prioritize communications of a mobile station in a priority communication system over communications of a mobile station in a non-priority communication system, in a network where the priority communication system and the non-priority communication system coexist in the same communication area.

Abstract: Disclosed herein is a recording medium comprising an alumina hydrate having an average pore radius of 20 to 200 ? and a half breadth of pore radius distribution of 20 to 150 ?.

Abstract: A signal reception device is disclosed that is able to improve interference cancellation capabilities even when signals having different center frequencies exist on the same frequency band. The signal reception device includes an interference suppression unit to generate replicas of plural signals in the received signal and separate the signals by suppressing interference signals. The interference suppression unit includes a signal phase rotator to rotate phases of the signal candidates at preset respective rotational frequencies, the preset rotational frequencies being related to respective center frequencies of the signals in the received signal; a rotational frequency controller to set the preset rotational frequencies; and a replica generator to generate the replicas of the signals by using the phase-rotated signal candidates.

Abstract: A frequency selection apparatus, a mobile communications system, and a multi-band resource management method are disclosed. The frequency selection apparatus includes an acquisition unit configured to collect environmental information about a mobile station for each frequency band according to system frequency bands that a mobile station can use, and a frequency selection unit configured to determine the frequency band to be used and the system to be connected to, based on the environmental information and information provided by the mobile station.

Abstract: A signal separator for separating multiple signals contained in a received signal from each other based on a replica of the received signal is provided.

Abstract: The present invention is to provide a communication channel with a low inter-cell interference while suppressing variation in the amount of inter-cell interference. Provided is a base station arranged in a radio communication system configured to implement a frequency division multiple access method by using a frequency division multiplexing method as a modulation method, and configured of cells each divided into an inner region and an outer region. The base station includes an allocation controller configured to perform subchannelization using a perfectly-orthogonal channel in the outer region of the cell, and to perform subchannelization using a quasi-orthogonal channel in the inner region of the cell.

Abstract: A destination station 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 to the destination station and transmits a pilot signal to the source station and a relay station, 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 and the relay station, 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: To provide a radio communication control apparatus and a radio communication control method capable of controlling simultaneous transmission and reception so as not to degrade system throughput. A simultaneous transmission and reception controller 106 determines whether the simultaneous transmission and reception using the same frequency are possible, based on radio spectrum environment information of an opposite party of communication and radio spectrum environment information of a self-apparatus. When the simultaneous transmission and reception using the same frequency are determined to be possible, a control signal transmission section 109 transmits instruction information, indicating that the simultaneous transmission and reception are possible, and a transmission parameter thereof, to the above communication terminal.

Abstract: To improve the channel capacity of an entire communication system in accordance with transmission quality of the channels of each node. A relay node has: a receiving section that receives a received signal from a source node; a channel estimation section that measures SNR of a backward channel between the source node and the relay node, and SNR of a forward channel between the relay node and a destination node; a relay selecting section that selects, from among a QR-P-ZF method, a QR-P-QR method and a ZF-P-QR method, a relay method of the relay node in accordance with the ratio between the SNRs of the backward and forward channels; a relay signal processing section that multiplies the received signal by a transmission weight matrix corresponding to the selected relay method, and thereby converts the received signal to a relay signal; and a transmitting section that transmits the relay signal to the destination node.