Abstract: There are obtained a transmitting apparatus capable of easily notifying information regarding radio waves required for an objective apparatus, a communication apparatus or a receiving apparatus capable of easily setting a frequency required at each place. a communication system or a broadcast receiving system employing the transmitting apparatus, the communication apparatus, and the receiving apparatus; and a control program, a communication method, and a broadcast receiving method to be used in the communication apparatus or the receiving apparatus. The radio wave tower 101 transmits not only radio waves for the television and the radio, but also the radio wave information 104 for communication and for reception of broadcasts by use of the radio wave information transmitting apparatus 102. For example, the portable terminal 106 first receives the radio wave information 104 in a new place and then obtains a center frequency based on the information for communication with the base station 110.

Abstract: To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal.

Abstract: To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal.

Abstract: To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal.

Abstract: There are obtained a transmitting apparatus capable of easily notifying information regarding radio waves required for an objective apparatus, a communication apparatus or a receiving apparatus capable of easily setting a frequency required at each place. a communication system or a broadcast receiving system employing the transmitting apparatus, the communication apparatus, and the receiving apparatus; and a control program, a communication method, and a broadcast receiving method to be used in the communication apparatus or the receiving apparatus. The radio wave tower 101 transmits not only radio waves for the television and the radio, but also the radio wave information 104 for communication and for reception of broadcasts by use of the radio wave information transmitting apparatus 102. For example, the portable terminal 106 first receives the radio wave information 104 in a new place and then obtains a center frequency based on the information for communication with the base station 110.

Abstract: A system for efficiently utilizing a transmission capacity without complicated processing a hierarchical code comprised of a plurality of layers having different error correcting capabilities. In a transmitter, an encoding unit encodes an image in accordance with a hierarchical coding scheme to generate a plurality of layer data. An error correcting code addition unit performs error correction coding on each of at least one layer data including the lowermost layer data in accordance with an error correction coding scheme which gives higher error correcting capabilities to a lower layer than a higher layer. A transmission unit transmits each of the layer data and error correcting codes onto a transmission path. A receiver corrects possible errors introduced on the path into the layer data received from the transmitter according to the error correction coding scheme, and decodes layer data received in a quality available for decoding to restore the image.

Abstract: A cellular system according to an exemplary aspect of the present invention is a cellular system in which a plurality of frequency carriers are available for communication between a base station and a mobile station, including: a first measurement unit for measuring a rate of time that interference power of a frequency carrier in uplink is more than a pre-determined threshold; a carrier availability/unavailability determining unit for putting the frequency carrier into an unavailable state if the time rate is more than a first threshold and putting the frequency carrier into an available state if the time rate is less than a second threshold; and a communication unit for using the frequency carrier in an available state for the communication between the base station and the mobile station.

Abstract: To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal.

Abstract: To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal.

Abstract: A system is provided for efficiently utilizing a transmission capacity without complicated processing by using a hierarchical code comprised of a plurality of layers having different error correcting capabilities. In a transmitter, an encoding unit encodes an image in accordance with a hierarchical coding scheme to generate a plurality of layer data. An error correcting code addition unit performs error correction coding on each of at least one layer data including the lowermost layer data in accordance with an error correction coding scheme which gives higher error correcting capabilities to a lower layer than a higher layer. A transmission unit transmits each of the layer data and error correcting codes onto a transmission path. A receiver corrects possible errors introduced on the transmission path into the layer data received from the transmitter in accordance with the error correction coding scheme, and decodes layer data received in a quality available for decoding to restore the image.

Abstract: In a transmission side, a k-bit parallel signal is divided into n signals, which are respectively encoded and then phase-shifted so as to causing a mutual phase difference of &pgr;/2n. Spectrum spreading is performed on the phase-shifted encoded signals which are combined together to produce a transmission digital signal. In a receiving side, reverse spreading is performed on a receiving signal to produce reverse-spread signals, which are given the phase difference to cancel the phase shift of the transmission side, and then decoded. Thus, the original k-bit parallel signal is reproduced in the receiving side.

Abstract: To provide an orthogonal frequency division multiplex modem circuit which can multiplex signals, whose bit rates and QoS are different from one another, and can transmit the signals via one OFDM line. A serial/parallel converter converts input signals into a complex parallel signal respectively, and a sub carrier and a modulation system are assigned every communication channel. A randomizer changes the alignment sequence of the signal, a discrete inverse Fourier transformer processes the signal, a parallel/serial converter converts the signal into a serial signal, and a transmitter performs the orthogonal modulation of the signal to output the signal from an antenna. A receiver performs orthogonal demodulation of the signal received with an antenna, a serial/parallel converter converts the signal into a parallel signal, and a discrete Fourier transformer processes the parallel signal.

Abstract: In a transmission diversity system for selecting one of a plurality of radio transmission systems in a base station to perform diversity transmission of data to a mobile station, the base station adds transmission data and identification signals different in the plurality of radio transmission systems to transmit resultant radio signals from the plurality of radio transmission systems, and transmits transmission data from one radio transmission system based on optimal radio transmission system information transmitted as a radio wave from the mobile station. The mobile station determines an identification signal representing an optimal reception state from the plurality of identification signals detected from the data received from the plurality of radio transmission systems of the base station and transmits the determined optimal radio transmission system information to the base station.

Abstract: In a spread spectrum device including a serial to parallel converter (14) for converting a serial information signal (10) into a parallel signal of n bits, where n represents an integer not smaller than two, an information modulator (20) carries out information modulation on m bits among the n bits of the parallel signal and produces a modulated information signal, where m represents a positive integer smaller than n. A selective spreading code producing circuit (21, 22) has spectrum spreading codes which are equal in number to 2.sup.(n-m) and are different from one another. The selective spreading code producing circuit selectively produces, as a selected spreading code, one of the spectrum spreading codes that is specified by remaining (n-m) bits among the n bits of the parallel signal. A spectrum spreading circuit (23) carries out spectrum spreading on the modulated information signal on the basis of the selected spreading code and produces a spectrum spread signal (13).

Abstract: In a base station transmitter/receiver of a cellular system, a plurality of antennas are oriented in each sector and radiate radio transmission signals and receive radio reception signals to produce received signals. A signal processing circuit is connected to the antennas to process the received signals into output reception signal and to process input transmission signal into the radio transmission signals in response to the received signal. Thus, the signal processing circuit serves to vary the directivities of the antennas in each sector and to thereby control a composite directivity formed by the varied directivities.

Abstract: In a spread spectrum device including a serial to parallel converter (14) for converting a serial information signal (10) into a parallel signal of n bits, where n represents an integer not smaller than two, an information modulator (20) carries out information modulation on m bits among the n bits of the parallel signal and produces a modulated information signal, where m represents a positive integer smaller than n. A selective spreading code producing circuit (21, 22) has spectrum spreading codes which are equal in number to 2.sup.(n-m) and are different from one another. The selective spreading code producing circuit selectively produces, as a selected spreading code, one of the spectrum spreading codes that is specified by remaining (n-m) bits among the n bits of the parallel signal. A spectrum spreading circuit (23) carries out spectrum spreading on the modulated information signal on the basis of the selected spreading code and produces a spectrum spread signal (13).

Abstract: It is an object of the present invention to provide a base station transmission-reception apparatus wherein an increase in the number of sectors does not increase the load to a control center arising from hand-over between sectors and does not increase the number of processing sections for each channel.

Abstract: In a variable modulation communication method, the transmission quality of a transmission path is monitored. If the transmission quality is good, communication is performed while the transmission time is shortened by using a multilevel modulation scheme. If the transmission quality is bad, communication is performed while the transmission time is prolonged by using a modulation scheme having a smaller number of levels than the multilevel modulation scheme. A variable modulation communication apparatus is also disclosed.

Abstract: A maximum likelihood sequence estimation apparatus decodes a digital data signal. The apparatus includes: a sampling device to perform sampling and to output a received signal by sampling pulses having a constant time interval T and N different sampling phases; an operation device to operate a branch metric of the received signal sampled by the N different sampling phases; and a device to perform maximum likelihood sequence estimation of the branch metric.

Abstract: According to a handoff method for a cellular digital mobile communication system, a communication test of a new channel is performed by utilizing a free time of a time-divisionally multiplexed channel. A mobile station of this invention includes a communication circuit for performing communication by using a time-divisionally multiplexed channel, a switching circuit for connecting a new channel during a free time of the time-divisionally multiplexed channel, and a communication test circuit for performing a communication test when the switching circuit is connected to the new channel.