Abstract: To accurately detect interference in a radar device, this radar apparatus 1 is provided with: an average amplitude calculation unit 122 that calculates an average amplitude of a beat signal based on a transmission signal and a reception signal; and an interference detection unit 123 that detects an interference signal with respect to the reception signal on the basis of the average amplitude of the beat signal calculated by the average amplitude calculation unit 122.

Abstract: A wireless transmitting apparatus inserts a training signal into a transmission burst at fixed symbol intervals as a pilot signal, a wireless receiving apparatus performs AD conversion of a received burst signal, performs symbol timing recovery, performs frame position detection and pilot signal extraction from the received burst signal for which symbol timing was established, performs frame synchronization, and performs a carrier frequency estimation using pilot signal. A carrier frequency estimation is also performed with respect to a received burst signal for which frame synchronization was established, and channel distortion is estimated and output based on a frequency-corrected received burst signal. Channel distortion estimation is then performed with respect to a frequency-corrected received burst signal, and a data symbol sequence of the channel-compensated received burst signal is converted to a received data bit stream.

Abstract: A wireless transmitting apparatus inserts a training signal into a transmission burst at fixed symbol intervals as a pilot signal, a wireless receiving apparatus performs AD conversion of a received burst signal, performs symbol timing recovery, performs frame position detection and pilot signal extraction from the received burst signal for which symbol timing was established, performs frame synchronization, and performs a carrier frequency estimation using pilot signal. A carrier frequency estimation is also performed with respect to a received burst signal for which frame synchronization was established, and channel distortion is estimated and output based on a frequency-corrected received burst signal. Channel distortion estimation is then performed with respect to a frequency-corrected received burst signal, and a data symbol sequence of the channel-compensated received burst signal is converted to a received data bit stream.

Abstract: An OFDM signal communication system used in broadband mobile communication, achieves stable operation under severe frequency selective fading environments, giving high quality. The OFDM signal communication system which transmits OFDM signals over the same radio frequency from N transmitting antennas, has an inverse matrix computer for computing an N×N inverse matrix constituted by propagation coefficients for respective propagation paths between each of N transmitting antennas and each of N receiving antennas, and a subcarrier demodulator which separates the signals of the respective propagation paths, based on the obtained inverse matrix.

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: An MSA feeder circuit (113) that feeds power to an MSA (112) and MSA (112) is disposed on an antenna substrate (106) and a high-output amplifier (102) and low-noise amplifier (103), etc., which are active devices, are mounted on an RF substrate (107). A heat radiation block (111) is interposed between the antenna substrate (106) and the RF substrate (107). An RF-antenna connection section (105) connects an MSA feeder circuit (113) disposed on the antenna substrate (106) and a feed line (109) on the RF substrate (107) through an electromagnetic field using a non-radiation connection slot (108). In this way, even when a device with high output and large power consumption is used, it is possible to provide an active antenna which can suppress deterioration of the characteristic and which can be implemented in a simple configuration and can be downsized.

Abstract: In an ATM transmission system in which a plurality of ATM cells are grouped to a packet with an end of ATM cell having an EOP (End Of Packet) flag, a transmitting station comprises a transmit buffer for storing temporarily ATM cells to be transmitted, a transmit cell process means which discards all the ATM cells in the group in case that a NAK response indicating loss or wrong reception of an ATM cell is received from a receiving station, and an EOP cell generator for transmitting an EOP cell which has said EOP flag in stead of the discarded ATM cells. As no ATM cell in a packet is transmitted after an erroneous ATM cell is detected, no useless ATM cell which would be discarded in a destination terminal equipment because of an erroneous ATM cell occupies a transmission line when an erroneous ATM cell is detected, and traffic is saved.

Abstract: An OFDM signal communication system used in broadband mobile communication, achieves stable operation under severe frequency selective fading environments, giving high quality. The OFDM signal communication system which transmits OFDM signals over the same radio frequency from N transmitting antennas, has an inverse matrix computer for computing an N×N inverse matrix constituted by propagation coefficients for respective propagation paths between each of N transmitting antennas and each of N receiving antennas, and a subcarrier demodulator which separates the signals of the respective propagation paths, based on the obtained inverse matrix.

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: An object of the present invention is to improve the transmission efficiency and reduce circuit size in error compensating techniques where bit errors occurring during transmission are compensated for by retransmission. Transmission equipment get sequence number(s) from control information and sequence numbers which follows from the sequence number which correspond to newest data packet amongst the sequence numbers. and transmits data packet corresponding to these sequence numbers at a predetermined timing. On the other hand, reception equipment receives data packet from the transmission equipment, and manages the sequence numbers of not yet received data packets. The reception equipment then sends back sequence number(s) of predetermined number, which is smaller number than the maximum number of data packets which is sent from transmission equipment at a predetermined timing, which correspond to not yet received data packet as control Information for each predetermined timing.

Abstract: An asynchronous transfer mode (“ATM”) cell transfer system in a wireless communication system provides quality classes that correspond to the amount of cell transfer delay allowed. Cells are classified according to a quality class and stored in buffers. The cells are read starting from the buffer for the quality class with the highest priority, and successively from buffers for quality classes of lower priority. Alternatively, if there is room in the output interval of cells of a higher priority quality class, cells of a lower quality class are inserted among these cells.

Abstract: An object of the present invention is to improve the transmission efficiency and reduce circuit size in error compensating techniques where bit errors occurring during transmission are compensated for by retransmission.Transmission equipment get sequence number(s) from control information and sequence numbers which follows from the sequence number which correspond to newest data packet amongst the sequence numbers, and transmits data packet corresponding to these sequence numbers at a predetermined timing. On the other hand, reception equipment receives data packet from the transmission equipment, and manages the sequence numbers of not yet received data packets. The reception equipment then sends back sequence number(s) of predetermined number, which is smaller number than the maximum number of data packets which is sent from transmission equipment at a predetermined timing, which correspond to not yet received data packet as control information for each predetermined timing.

Abstract: A digital transmission apparatus is provided, by which the amount of transmission delay and circuit miniaturization can be realized in the case of using an FEC method together with a differential coding method. In the digital transmission apparatus, a digital signal to be transmitted is serial-to-parallel-converted into parallel n-channel signals; each signal is FEC-encoded and encoded signals are then differentially encoded; and a carrier is modulated by the parallel n-channel differentially-encoded signals to be transmitted as a 2.sup.n multi-level modulated signal. The signal is detected at the receiving side and parallel n-channel demodulated and decoded signals are output; FEC decoding is performed; and the parallel n-channel digital signals after FEC decoding is parallel-to-serial-converted.

Abstract: A group demodulator for FDMA/PSK input signals comprising a down-converter for the input signals to convert these signals into in-phase and quadrature-related signals which are applied through analog-to-digital converters to a digital transmultiplexer. The digital transmultiplexer converts the signals into a number of channels of PSK modulated data. The output of each analog-to-digital converter is applied to an automatic threshold controller which detects the statistical bias of the input signal amplitude. Each automatic threshold controller provides an analog reference signal which is applied to a reference input of the associated analog-to-digital converter. The reference signal corrects any DC offset error for the analog-to-digital converter and prevents degradation in energy per bit-to-noise density ratio.