Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: A receiver circuit includes an LPF configured to remove an interference signal and/or a noise from a received signal, an ADC configured to digitize a signal output from the LPF, an FIR filter configured to further remove an interference signal and/or a noise from the signal output from the ADC and compensate imperfection in in-band characteristics caused in the LPF, a delay circuit configured to delay the signal output from the ADC by a predetermined time period, and a control circuit configured to control a destination of the signal output from the ADC, wherein the control circuit switches the destination of the signal output from the ADC to one of the FIR filter and the delay circuit according to a predetermined condition.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: A mobile communications terminal includes positional information generator configured to generate positional information indicating a current position of the terminal, receiver which receives identification information sent from the base station of the second mobile communication network, notification information generator configured to generate notification information including the identification information and the positional information generated at the time of receiving the identification information, and transmitter which transmits the notification information to the service area calculation apparatus via the first mobile communication network to derive the information concerning the service area.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: A receiver circuit includes an LPF configured to remove an interference signal and/or a noise from a received signal, an ADC configured to digitize a signal output from the LPF, an FIR filter configured to further remove an interference signal and/or a noise from the signal output from the ADC and compensate imperfection in in-band characteristics caused in the LPF, a delay circuit configured to delay the signal output from the ADC by a predetermined time period, and a control circuit configured to control a destination of the signal output from the ADC, wherein the control circuit switches the destination of the signal output from the ADC to one of the FIR filter and the delay circuit according to a predetermined condition.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.

Abstract: An apparatus used in a first mobile communication system with a plurality of wireless base stations, the first mobile communication system operated by a first provider, the apparatus including an acquiring unit, a location detecting unit configured to detect a present location of the apparatus, a storing unit configured to store first service location information with respect to the first provider, and a location information providing unit configured to calculate locally a location of the plurality of wireless base stations using the detected present location of the apparatus stored in the storing unit. The location information providing unit is configured to provide a user with information based on the first service location information and the second service location information.

Abstract: A radio receiver comprises an LNA which amplifies An RF signal, a quadrature demodulator which directly demodulates the amplified RF signal into a B/B signal, using a LO signal, a VGA which amplifies the B/B signal, a DC offset canceller which executes feedback control on the amplified B/B signal, and a gain controller which controls at least the gain of the LNA, the gain controller including a signal intensity detector which detects the intensity of the amplified B/B signal, a gain selector which selects a desired one of preset gains on the basis of the detected intensity, a timing controller which controls timing of switching to the selected desired gain, and a gain control signal generator which changes, in accordance with the controlled timing, the interval at which an LNA gain control signal is generated.

Abstract: A mobile communications terminal includes positional information generator configured to generate positional information indicating a current position of the terminal, receiver which receives identification information sent from the base station of the second mobile communication network, notification information generator configured to generate notification information including the identification information and the positional information generated at the time of receiving the identification information, and transmitter which transmits the notification information to the service area calculation apparatus via the first mobile communication network to derive the information concerning the service area.

Abstract: A radio has a test signal generating portion, an orthogonal modulator for, provided with a first electric signal of a first frequency, transforming the test signal at the first frequency and outputting it as a modulated signal, a first amplifier for amplifying the modulated signal, a second amplifier, capable of inputting the modulated signal frequency-converted by using a difference frequency signal indicating a frequency difference between the first electric signal and a second electric signal of a second frequency and the amplified modulated signal, for amplifying the inputted modulated signal, an orthogonal demodulator for, provided with the second electric signal, transforming the modulated signal at the second frequency and outputting it as a demodulated signal, and an analysis portion for, provided with the demodulated signal and the test signal, analyzing characteristics of at least one of the orthogonal modulator and the orthogonal demodulator.

Abstract: An apparatus used in a first mobile communication system with a plurality of wireless base stations, the first mobile communication system operated by a first provider, the apparatus including an acquiring unit, a location detecting unit configured to detect a present location of the apparatus, a storing unit configured to store first service location information with respect to the first provider, and a location information providing unit configured to calculate locally a location of the plurality of wireless base stations using the detected present location of the apparatus stored in the storing unit. The location information providing unit is configured to provide a user with information based on the first service location information and the second service location information.

Abstract: The present invention is intended to provide a mobile communication terminal permitting a user to obtain location information of wireless base station which provides contents data in certain areas. The terminal accumulates identification information of wireless base stations when wireless services are received. The invention has functions of interrelating the identification information with location information of the terminal when the services are received and of storing both kinds of information. Wireless LAN service areas are displayed together with map information.

Abstract: A mobile communications terminal includes positional information generator configured to generate positional information indicating a current position of the terminal, receiver which receives identification information sent from the base station of the second mobile communication network, notification information generator configured to generate notification information including the identification information and the positional information generated at the time of receiving the identification information, and transmitter which transmits the notification information to the service area calculation apparatus via the first mobile communication network to derive the information concerning the service area.