Abstract: A communication device includes a transmitter to transmit a radio transmission signal having a frequency different from a frequency of a radio transmission signal transmitted by another transmitter, a receiver to receive a receiving signal including a primary signal and a first passive intermodulation signal generated by radio transmission signals, a memory, and a processor coupled to the memory and the processor to calculate a power of the primary signal, update a first coefficient for generating a cancel signal for canceling the first passive intermodulation signal, based on the receiving signal and transmission signals to be transmitted, generate the cancel signal based on the transmission signals and the first coefficient, and combine the receiving signal and the cancel signal, wherein the processor is further to adjust a step coefficient, which is a time constant in case of updating the first coefficient, based on the power of the calculated primary signal.

Abstract: A multiplexing device for multiplexing uplink signals transmitted from each of a plurality of radio devices and outputting the multiplexed signal to a radio control device performs a calculation processing that calculates a power value of the uplink signal for each radio device, performs a determination processing that determines whether or not noise of a radio device that transmits an uplink signal is dominant among signal components included in the uplink signal, using the power value of the uplink signal, performs a blocking processing that blocks the uplink signal in which the noise is dominant in a case where the noise is determined to be dominant among the signal components included in the uplink signal, and performs a multiplexing processing that multiplexes uplink signals that are not blocked among the uplink signals for each radio device, and outputs the multiplexed signal to the radio control device.

Abstract: A wireless communication device includes: a transmitting circuit that is connected to an antenna and includes a power amplifier that amplifies an input signal; a receiving circuit that is connected to the antenna and includes a switch that switches as to whether or not a signal is received; and a processor that executes a process including: acquiring timing information that indicates timing of a guard period when no signal is transmitted or received by the antenna; turning on the power amplifier and turning on the switch in the guard period based on the acquired timing information to input a noise signal of the transmitting circuit that is amplified by the power amplifier to the receiving circuit; measuring electrical power of a signal that is output from the receiving circuit in the guard period; and determining abnormality of the receiving circuit based on the measured electrical power.

Abstract: A communication device includes a sending unit that sends a plurality of signals that are to be wirelessly sent with different frequencies; an acquiring unit that acquires a reception signal to which an intermodulation signal that is produced due to intermodulation of the plurality of signals is added; and a processor that is connected to the sending unit and the acquiring unit. The processor generates, on the basis of the plurality of signals sent by the sending unit, a cancellation signal corresponding to the intermodulation signal and combines the generated cancellation signal with the reception signal acquired by the acquiring unit.

Abstract: A radio receiver includes a branching unit, a first gain-control system, a second-gain control system, and a signal processing unit. The branching unit branches a radio signal received by the radio receiver into two signals. The first-gain control system performs a gain control of a pilot signal in one of branched signals, and the second gain control system performs a gain control of a data signal in another of the branched signals. The signal processing unit synchronizes frames in the received radio signal. The signal processing unit outputs a gain signal to each of the first gain-control system and the second gain-control system. The first gain-control system and the second gain-control system perform the gain controls based on the gain signal.

Abstract: Disclosed is a transmitting apparatus for transmitting a signal, which has been obtained by applying an inverse Fourier transform to a plurality of digital subcarrier signals having frequencies that differ from one another, after subjecting the signal to at least a digital-to-analog conversion. Frequencies in the vicinity of 0 Hz are not used as frequencies of valid subcarrier signals. Further, frequencies included in frequency ranges of f?M/2 to f?N/2, fM/2 to f(N/2)?1 are used as the frequencies of the valid subcarrier signals, where N-number of subcarrier frequencies are represented by f?N/2, f(?N/2)+1, . . . , f0, f1, . . . f(N/2)?1 and frequencies on both sides farthest from 0 Hz that are not used as the frequencies of the valid subcarrier signals are represented by f?M/2, fM/2.

Abstract: A radio receiver includes a branching unit, a first gain-control system, a second-gain control system, and a signal processing unit. The branching unit branches a radio signal received by the radio receiver into two signals. The first-gain control system performs a gain control of a pilot signal in one of branched signals, and the second gain control system performs a gain control of a data signal in another of the branched signals. The signal processing unit synchronizes frames in the received radio signal. The signal processing unit outputs a gain signal to each of the first gain-control system and the second gain-control system. The first gain-control system and the second gain-control system perform the gain controls based on the gain signal.

Abstract: Disclosed is a transmitting apparatus for transmitting a signal, which has been obtained by applying an inverse Fourier transform to a plurality of digital subcarrier signals having frequencies that differ from one another, after subjecting the signal to at least a digital-to-analog conversion. Frequencies in the vicinity of 0 Hz are not used as frequencies of valid subcarrier signals. Further, frequencies included in frequency ranges of f?M/2 to f?N/2, fM/2 to f(N/2)?1 are used as the frequencies of the valid subcarrier signals, where N-number of subcarrier frequencies are represented by f?N/2, f(?N/2)+1, . . . , f0, f1, . . . f(N/2)?1 and frequencies on both sides farthest from 0 Hz that are not used as the frequencies of the valid subcarrier signals are represented by f?M/2, fM/2.