Abstract: A wireless communication system comprises a mobile station and a base station, which use a plurality of communication channels and a pilot channel corresponding to at least one of the communication channels. The base station has a transmitting unit that employs at least one of the communication channels as a priority channel and transmits channel information of this priority channel and the other channels by use of a communication channel other than the pilot channel. The mobile station has a determining unit that determines a reception level of the pilot channel; an acquiring unit that acquires the channel information transmitted via the communication channel other than the pilot channel; and a deciding unit that decides, as an available communication channel, at least one of the communication channels based on both the channel information acquired by the acquiring unit and the reception level determined by the determining unit.

Abstract: The present invention enables assignment to a terminal a sub-band having satisfactory communication quality. A reference-signal reception unit receives from a terminal a reference signal spreading over sub-bands. A communication-quality measurement unit measures the communication quality of each of the sub-bands on the basis of the reference signal. A sub-band assignment unit assigns one of the sub-bands to the terminal on the basis of the communication quality, for the terminal to perform wireless communication with the communication device. A reference-signal transmission unit transmits to the communication device a reference signal spreading over the sub-bands. A sub-band-assignment-information reception unit receives information on one of the sub-bands which is assigned to the terminal by the communication device on the basis of the reference signal. A data transmission unit transmits data to the communication device through the sub-band assigned to the terminal.

Abstract: In a case where multiple kinds of frames having different lengths (Ngi_s and Ngi_l) of guard intervals inserted before the head of the effective data, the length of the guard intervals are adjusted in such a manner that at least the position of a part of the effective data is are apart from frame timing by the same amount. Thereby, on the receiving end, it is always possible to perform reception processing such as FFT processing in an appropriate time division at a fixed timing, without causing sample deviation of the effective data.

Abstract: A receiving device and a communication system wherein the frequency usage efficiency is raised to improve the communication throughput.

Abstract: In transmission in which MIMO is applied, there have been problems that the number of variable parameters increases and the number of information bits necessary for control channel increases. When the number of simultaneous multiplex users in one frame increases, there is also a problem of increased control channel information in proportion to the number of users. Error correction coding is performed for the control channel information based on the Adaptive Modulation and Coding scheme, and the above error correction coded control channel information is transmitted after being modulated with a predetermined modulation scheme, and further, according to propagation condition, the coding rate in the above error correction coding is made variable.

Abstract: An equalizer device which enables tap coefficient correction accuracy to be improved to enable high-quality adaptive equalization. A tap coefficient filter corrects tap coefficients thereof in accordance with a control signal and equalizes a received signal in which a data signal is multiplexed with a pilot signal, which is a known signal for compensating for variation in reception of the data signal. A training signal setter sets both of the data signal and the pilot signal as a training signal, which indicates an ideal value of equalized output. A tap coefficient corrector obtains an error signal indicative of a differential value between the training signal and a filter output signal which is output from the tap coefficient filter after being equalized, performs an adaptive algorithm operation so as to decrease the error signal, and generates the control signal for correcting the tap coefficients.

Abstract: A channel estimation device in wireless communication in use of a plurality of subcarriers for communication, comprises: a first channel estimation section which performs channel estimation for each subcarrier based on pilot signals mapped to each subcarrier; a second channel estimation section which further estimates channels for each subcarrier using channel estimation values estimated by the first channel estimation section; and a channel selection section, which selects and outputs the first and second channel estimation values estimated by the first and second channel estimation sections, according to the subcarrier.

Abstract: A mobile communication terminal (UE) comprises: a transmitting unit (213, 211) which transmits a signal via a radio resource allocated to the mobile communication terminal (UE) for the transmission of a prescribed control signal; and a signal selector unit (214) which, when upstream traffic occurs, selects a reservation request signal as the signal to be transmitted via the allocated radio resource wherein, when the mobile communication terminal (UE) is in a standby state, the reservation request signal is transmitted from the mobile communication terminal (UE) to the base station (BS) by using the radio resource allocated to the mobile communication terminal (UE) for the transmission of the prescribed control information.

Abstract: A wireless terminal receives a signal from a first BTS as a communication party and a signal from a second BTS when receiving the signal from the first BTS by using a communication slot that is assigned to the terminal, the terminal comprises receiving antennas; a demodulator unit that estimates channels of received signals, and demodulates the received signals by using the estimation result; and a discriminating unit discriminating the number of transmitting antennas to be used in the first BTS in the communication slot which is assigned to the terminal, in which in the case where the number of channels that are produced between the first BTS and the terminal, which is determined according to the number of transmitting antennas, is smaller than the number of channels that can be estimated by the demodulator unit, the demodulator unit estimates the channel between the terminal and the first BTS by using a signal from the first BTS, and estimates the channel between the terminal and the second BTS by using a s

Abstract: A mobile communication system in which, when transmission is performed from a base station to a terminal device, a modulation scheme is designated, from among at least two modulation schemes with different modulation levels, on the basis of reception quality at the terminal to perform transmission from the base station. The system includes a base station transmitting at a first transmission power using a frequency designed for, in a channel allocation scheme of the system, not causing interference with an adjacent base station and using a first modulation scheme, and a second channel transmitting at a second transmission power lower than the first transmission power, and when the base station uses the second channel, a second modulation scheme having a lower modulation level than the first modulation scheme is designated, and communication is performed.

Abstract: Reference phase is a radio communication system using orthogonal M-ary modulation is determined, so that a coherent detection system for a CDMA radio communication system is readily achieved. The determination of reference phase is performed by the step of determining a reference phase in a radio communication system, which uses orthogonal M-ary codes comprising the steps of determining the correlation values of an in-phase component and quadrature component corresponding to respective Hadamard matrices resulting from fast Hadamard transform or inverse Hadamard transform of a signal, which possesses said in-phase component and quadrature component, and which is sent from the sending end by phase shift keying an orthogonal M-ary code computing the sum of the squares of the respective correlation values of said in-phase component and quadrature component and selecting either said fast Hadamard transform or inverse Hadamard transform output, which outputs a maximum value of said computed sum of the squares.

Abstract: MIXR is implemented with a realistic amount of hardware even when the number of detected paths is large. From among path timings detected by a path searcher and MICTs generated based on the detected path timings, as many timings as there are fingers are selected by a timing selector and the selected timings are assigned to the fingers. When selecting the timings, the value of SNIR expected to be achieved by RAKE combining in a RAKE combiner, for example, is predicted by calculation from a received signal, and the path timing and MICT that maximize the SNIR are selected.

Abstract: In a radio communication system in which multiple bands or a plurality of different radio frequencies are used, a different radio transmission method is used in each band or at each radio frequency. For example, by transmitting data using radio formats which are different in each band or at each radio frequency, the radio transmission method is made different in each band or at each radio frequency. In order to vary the radio format, (1) the pilot length is varied at each radio frequency; or (2) the pilot interval is varied at each radio frequency; or (3) the guard interval length is varied in each band or at each radio frequency; or (4) when multicarrier modulation is used for radio communication in each band, the subcarrier interval for multicarrier transmission is varied in each band.

Abstract: The radio communication system, comprises: a base station; and a plurality of terminals which perform reservation request for radio resources necessary for data transmission to said base station at random, wherein each of the plurality of terminals are allocated with individualized radio resources for reservation request necessary for the terminal to perform the reservation request to the base station. As a result, the occurrence of collision of reservation requests is eliminated.

Abstract: For transmitting predetermined information to a second communication station via a first communication station, the second communication station receives the predetermined information via one first communication station from among a plurality of the first communication stations. Upon transfer of a function of transferring the predetermined information to the second communication station to another first communication station, the another first communication station receives the predetermined information from the one first communication station, and transfers the same to the second communication station, with attaching distinction information to the predetermined information for distinguishing between the predetermined information transferred to the second communication station via the another first communication station and the predetermined information received from the another first communication station directly.

Abstract: A radio channel control method for controlling, in a radio communication system having a transmitter and a receiver, a radio channel from the transmitter toward the receiver. The method includes measuring a reception condition of a specific signal transmitted from the transmitter, obtaining control signals which indicate a changing in transmission power and another transmission parameter of the transmitter by measuring reception condition of the specific signal, and transmitting the control signals from the receiver.

Abstract: A radio channel control method for controlling, in a radio communication system having a transmitter and a receiver, a radio channel from the transmitter toward the receiver. The method includes receiving a signal transmitted from the transmitter by the receiver, measuring reception quality of the signal, generating information which indicates increment or decrement of the reception quality, and controlling a modulation or coding for the radio channel based on the information.

Abstract: A base station used in a radio communication system includes a transmitting unit operable to transmit a signal to a receiver and a receiving unit operable to receive control signals indicating a changing in transmission power and another transmission parameter of the base station from the receiver which generates the control signals by measuring reception condition for a specific signal transmitted from the base station.

Abstract: A base station used in a radio communication system includes a transmitting unit operable to transmit a signal to a receiver and a controller operable to control a modulation or coding of a radio channel according to a decision made by using information which indicates increment or decrement of reception quality of the signal.

Abstract: To provide a radio communication apparatus and a radio communication method in which change in the transmission rate is taken into consideration at the time of making transmission reservation. The present invention provides a radio communication apparatus for receiving the transmission reservation request with a radio transmitting/receiving unit and transmitting the reservation acknowledgement from the same radio transmitting/receiving unit. This radio communication apparatus is characterized in comprising a control unit for transmitting, from the radio transmitting/receiving unit, a plurality of reservation acknowledgments in different contents for a transmission reservation request in different timings.