Abstract: A frequency band allocation device is disclosed. The frequency band allocation device comprises an RF database (112) for storing frequency category information indicating a dedicated frequency band, a registered frequency band or unlicensed frequency band; a user information database (113) for storing user information; a frequency band selecting unit (1161, 1162) for selecting usable frequency bands based on the frequency category information and the user information; and a frequency band allocation unit (1163) for allocating a frequency band satisfying user required QoS out of the selected usable frequency bands.

Abstract: A transmitter used in the multiband environment includes a frequency allocation unit (106) configured to select and allocate a frequency band that satisfies a user QoS from among multiple separate frequency bands currently available for the user, a parameter determination unit (111) configured to determine a transmission parameter required for signal transmission based on the allocated frequency band, and a multi-user scheduling control unit (110) configured to determine a transmission schedule for multiple users taking into account the frequency bands allocated to the multiple users.

Abstract: A frequency band allocation device is disclosed. The frequency band allocation device comprises a frequency band selection unit (1161, 1162) for selecting usable frequency bands from a dedicated frequency band, a registered frequency band and an unlicensed frequency band; and a frequency band allocation unit (1163) for allocating a frequency band out of the selected usable frequency bands to an uplink and downlink, so as to satisfy user required QoS.

Abstract: A frequency band allocation device is disclosed. The frequency band allocation device comprises a frequency band selection unit for selecting usable frequency bands from a dedicated frequency band, a registered frequency band and an unlicensed frequency band; and a frequency band allocation unit for allocating a frequency band out of the selected usable frequency bands to a user, so as to satisfy user required QoS and maximize system frequency utilization factor.

Abstract: When OFDM signals are transmitted from a plurality of antennas, a pilot carrier is transmitted from one antenna among the plurality of antennas, and a null signal is transmitted from an antenna other than that antenna by a subcarrier of the frequency band that transmits the pilot carrier.

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: 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: 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 digital communication system using superposed transmission of high and low speed digital signals capable of transmitting superposed high and low speed digital signals through an identical frequency band efficiently by increasing a simultaneously transmittable number of channels in the low speed digital signals, while achieving the practically reasonable bit error rate performances for both the high speed digital signals and the low speed digital signals.