Abstract: A repeating station, a communication apparatus, and an antenna directivity control method are disclosed. The repeating station includes a first antenna group including at least one antenna element, a second antenna group that is different from the first antenna group, the second antenna group including two or more antenna elements adjusted so that radiation in the direction of the first antenna group is reduced, wherein the second antenna group is adjusted such that radiated power in the direction of the first antenna group is reduced.

Abstract: A radio communication system including a transmitter and a receiver (100) for transmitting MIMO channel signals is provided. The transmitter comprises a pilot signal insertion controller (93) for inserting a pilot signal for channel estimation into at least a leading frame; and an information symbol controller for controlling the number of information symbols to be contained in a frame, based on the existence of the pilot signal. The receiver comprises a received signal replica generator (112) for generating received signal replicas based on previously obtained provisional channel estimation values and transmission signal estimation values; a canceller (111) for removing, from a received signal, received signal replicas of at least a part of streams that are not channel estimation target streams; and a channel estimation value generator (113) for generating channel estimation values by a filter using outputs from the removing unit and the transmission signal estimation values.

Abstract: A wireless positioning apparatus includes a multipath delay estimator configured to estimate multipath delay components from one or more received signals; a selector configured to select appropriate delay estimates from the estimated multipath delay components according to a predetermined criterion; a storage configured to store an NLOS delay function defining prior statistics of information about non-line-of-sight delays; and a position estimator configured to estimate a position of a mobile station based on the selected delay estimates and the NLOS delay function read out from the storage.

Abstract: An OFDM transmitter (100) is disclosed. The OFDM transmitter comprises: a sorter (103-1) for sorting plural input complex signals and partitioning them into plural groups; plural IFFTs (103-2) for performing inverse Fourier transform on the input complex signals in groups; a peak reducer (103-4) for performing peak reduction, based on outputs from at least one of the IFFTs; and a multiple discrete signal generator (103-5) for generating a designated number of discrete signals from outputs of the peak reducer.

Abstract: An OFDM transmitter transmits an OFDM signal by a frame having a plurality of transmission symbol periods constituted of an effective symbol period for transmitting an information bit and a guard interval. The OFDM transmitter includes a guard interval length decider configured to decide a guard interval length in accordance with a feedback signal from an OFDM receiver; and a guard interval length changer configured to change a guard interval length in each transmission symbol period, in accordance with a decided guard interval length without changing a frame length.

Abstract: A transmitter has a peak reducing part carrying out peak reduction processing; an OFDM signal generating part generating an OFDM signal from an input information signal; a cyclic shifting part generating a signal obtained from cyclically shifting the OFDM signal; and an adding part adding the OFDM signal and the cyclically shifted signal together.

Abstract: A radio relay system is disclosed that is capable of preventing communication degradation in a case where radio signals are relayed using the same frequency band in a mobile communication environment. The radio relay system includes a first radio station, a second radio station, and a radio relay apparatus for relaying a radio signal that is exchanged between the first radio station and the second radio station. The radio relay apparatus includes a phase correction determining unit that determines a phase correction amount of the relayed signal based on channel information pertaining to channels established between the first radio station, the second radio station, and the radio relay apparatus, and a phase correction unit that corrects the relayed signal based on the phase correction amount determined by the phase correction determining unit.

Abstract: A radio repeater including at least first and second relay systems, each including a reception antenna configured to receive a radio signal, a loop interference suppressor, connected to the reception antenna, configured to suppress a loop interference signal in the received radio signal from said reception antenna, an amplifier configured to amplify the loop interference-suppressed radio signal from the loop interference suppressors, and a transmission antenna having a polarization characteristic, which is orthogonal to a polarization characteristic of said reception antenna, configured to transmit the output of said amplifier.

Abstract: An OFDM receiver receives an OFDM signal transmitted from an OFDM transmitter by using a sub-carrier. The OFDM receiver includes a channel estimator configured to obtain a channel estimated value of each multi-path based on OFDM signals received through a plurality of multi-paths; a transmission signal estimated value calculator configured to calculate a transmission signal estimated value as an estimated value of the OFDM signal; and an inter-carrier interference compensator configured to extract a multi-path not becoming a form to contain a signal component only of a target symbol in an FFT window based on the transmission signal estimated value and the channel estimated value of each multi-path, and to compensate for inter-carrier interference in the OFDM signal based on signal components corresponding to all sub-carriers of the multi-paths.

Abstract: A mobile terminal comprises a transmitter/receiver configured to transmit/receive a signal to/from a base station, a communication state determination unit configured to determine a communication state of the transmitter/receiver, a movement state measurement unit configured to measure a movement state of the mobile terminal, and a reception period controller configured to control a reception period for receiving a control signal transmitted from the base station by the transmitter/receiver, based on a communication state determination result determined by the communication state determination unit and a movement state measurement result measured by the movement state measurement unit.

Abstract: An object of the present invention is to enable appropriate switching among a plurality of modes including a cellular communication mode and an RFID information receiving function. A communication system is comprised of an RFID configured to transmit predetermined ID information of its own, a server capable of being connected to a cellular communication network, and an aggregation point for aggregating information from the RFID. In the communication system, the aggregation point, which is comprised of a mobile communication terminal or the like, is provided with an ID receiver for receiving ID information from an RFID, and a cellular communication part for performing cellular communication via the cellular communication network.

Abstract: In a method and an apparatus of transmitting a burst signal when the burst signal is transmitted from a transmitting station to a receiving station at a transmission power value and/or a transmission rate determined in accordance with a state of a radio channel between the transmitting and receiving station in a mobile communication system, based on a comparison result between a criterion predetermined according to a state of the radio channel and/or a transmission waiting state of the signal, whether or not the burst signal is to be transmitted is determined, and, when it is determined that the burst signal is to be transmitted, the burst signal is transmitted from the transmitting station to the receiving station.

Abstract: Symbols converted by a serial-to-parallel converting part (12) from serial to parallel form are subjected to inverse Fourier transform processing in an inverse Fourier transform part (13) as sub-carrier signal components of a frequency interval equal to the symbol rate, then the levels of the resulting time domain signal components are compared with a permissible peak level Cth in a peak component detecting part (22) to detect peak components, and the peak components are transformed by a Fourier transform part (23) to frequency domain components, which are subtracted by subtractors (240 to 24N-1) from the corresponding sub-carrier signal components to thereby reduce the peak power.

Abstract: In a multicast transmission system in which the same information is transmitted from a base station to a plurality of mobile stations, the mobile station sends a retransmission request signal to the base station when detecting an error in a received multicast signal. The base station judges whether a received signal indicates a retransmission request according to receiving quality of the received signal, and retransmits a multicast signal corresponding to the retransmission request when the received signal indicates the retransmission request. In addition, The base station monitors a receiving state of a multicast signal in the mobile stations, and changes a transmission method to conform to the receiving state according to a result of monitoring, and sends a multicast signal.

Abstract: In an adaptive equalizing apparatus for MIMO (Multi-Input Multi-Output) turbo reception, an interference component in a received signal is subtracted therefrom using a replica of an interference component in an interference canceling part 31n, the subtracted output is filtered by a filter 32n, to cancel the remaining interference component and to perform multi-path combining, and in a degree-of-interference-cancellation estimation part 41n the degree of interference cancellation ?(i) is set such that it is 0 for the iteration number i=1, 0.8+0.05 (i?1) for 5?i?2 and 1 for i?6, and at the beginning of each iteration filter coefficients are calculated using ?(i) and a channel estimation value in a filter coefficient calculating part 33n and the filter coefficient thus calculated are set in the filter 32n. An average value of soft decision symbol estimation values used in the interference canceling part may be used as ?.

Abstract: The accuracy of an equalization start timing, an equalization duration and a channel estimation is improved in an application including an increased number of users. An equalization start timing t0, an equalization duration te and channel H estimation are performed for each user signal, and using these, received signal replicas Re1 ro ReN for the respective users are generated. The replicas are subtracted from the received signal to provide an error signal, and Re1 to ReN are added to Es to provide an interference suppressed received signals for the users 1 to N. to, te, H and Re1 to ReN are generated from these to generate Es in a repeated fashion to improve the accuracy of t0, te and H.

Abstract: In a wireless communication system formed by a plurality of access points constituting a wireless network, through which user terminals make accesses, and at least one control station configured to control the access points, public access points are systematically set up by a manager of the control station, while user's personal access points to be freely set up by users at desired locations according to needs of users are accommodated by operating the control station to measure a utilization level of each user's personal access point and charge an owner of each user's personal access point according to a measured utilization level and set up relay routes using the public access points and the user's personal access points.

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 includes a plurality of antenna elements for receiving a radio signal from a radio transmitter; a setting part changing an impedance of at least one of the plurality of antenna elements according to an instruction signal; a measuring part measuring a change in throughput in a received signal caused due to the change in the impedance; and an instruction part providing the instruction signal which is changed in response to the measurement result.

Abstract: An object of the present invention is to provide a communications system etc., which can reduce the influence of interference from other systems which results from a difference in symbol length, in an area where a plurality of systems using different transmission methods are mixed. The present invention relates to a communications system in which a plurality of systems share the same frequency bandwidth so as to transmit information symbols. One of the plurality of systems 1 includes an identifying unit 109 configured to identify the symbol length of an information symbol transmitted in a different system 2; and an adjusting unit 102, 107 configured to adjust the symbol length of an information symbol to be transmitted, in accordance with an identified symbol length.