Abstract: A calculation server estimates a position of a mobile terminal that communicates with a base station incorporated with received global positioning system satellite signals. The calculation server includes a positioning information analyzer configured to select one of the positioning modes to be used out of a cell/sector positioning mode and a hybrid positioning mode on the basis of a distance between a cellular base station and the mobile terminal, and a position detector configured to calculate the position of the mobile terminal in the positioning mode selected by the positioning information analyzer.

Abstract: A radio communication apparatus for performing transmission and reception based on radio communication includes: a power suppressor for coupling loop interference signal for attenuating signal power of a received signal to suppress the coupling loop interference signal power of the received signal; and a transceiver having a coupling loop interference signal removal function for analog domain and/or a coupling loop interference signal removal function for digital domain, for removing a coupling loop interference signal contained in a signal output from the power suppressor for coupling loop interference signal.

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: A correlation between a received signal and a sync word signal is calculated. A window signal having a time span which is equal to an equalization range for an adaptive equalizer is defined. A power sum of the correlation output signal in each of window signals #1, #2, #3, . . . are calculated by sequentially shifting the window signal in the time domain, and a rising edge of the particular window signal whose power sum maximum defines a symbol sync timing.

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.

Abstract: This invention provides an MIMO communication system and MIMO communication method. An MIMO receiver estimates state of each communication channel from the received signals received by #1 to #L antennas, generates feedback information according to the information of channel state, sends the feedback information to a transmitter through a feedback path, processes the feedback information in order to compensate feedback-delay of the feedback path, generate K*L proper reception weights by using the information of channel state and processed feedback information, multiplies the received #1 to #L substreams of respective #1 to #K signal streams by the proper #1 to #L reception weights, respectively, composes the #1 to #L weighted substreams to obtain respective composed #1 to #K signal streams and demodulate the composed #1 to #K signal streams, respectively, and combines the demodulated K signal streams to reproduce an original transmission signal.

Abstract: An object of the present invention is, in a communication path of which received signal quality is extremely poor, to prevent such a state of the communication failure. To a frame generator 13 in a transmitter 10, which transmits OFDM signal, a pilot & data arrangement format determiner 20, which determines pilot & data arrangement format of an OFDM signal based on the value of received signal quality at a receiver 30, a pilot symbol number determiner 19, which determines the number of pilot symbols based on the value of received signal quality, and a power amplification rate determiner 18, which determines power amplification rate based on the value of received signal quality, are newly provided. Thereby, it is possible to change the pilot & data arrangement format, the number of pilot symbols and the power amplification rate depending on the value of received signal quality to generate transmission signal frame of the OFDM signal.

Abstract: A correlation between a received signal and a sync word signal is calculated. A window signal having a time span which is equal to an equalization range for an adaptive equalizer is defined. A power sum of the correlation output signal in each of window signals #1, #2, #3, . . . are calculated by sequentially shifting the window signal in the time domain, and a rising edge of the particular window signal whose power sum maximum defines a symbol sync timing.