Abstract: A MIMO communication method for performing MIMO communication between a base station including a plurality of antennas, and a plurality of terminals accommodated in the base station. The method includes, in the base station, dividing the plurality of terminals into a first and a second group, and assigning orthogonal codes with each other to the respective groups, spreading transmission data to the plurality of terminals with the assigned codes, multiplying data obtained by the spreading by a predetermined pre-coding matrix, obtaining a channel matrix representing channels between the plurality of antennas and the plurality of terminals, multiplying data obtained by the multiplying by the pre-coding matrix by a complex conjugate matrix of the channel matrix, and transmitting data obtained by the multiplying by the complex conjugate matrix from the plurality of antennas.

Abstract: A Multiple Input Multiple Output (MIMO) communication method and system for performing communication between N (N is an integer greater than or equal to 2) transmitting devices each having a transmit antenna and at least one receiving device having N receive antennas by using a multi-user MIMO scheme. The method includes dividing the N transmitting devices into a plurality of sets, and assigning an orthogonal code to each set of transmitting devices as a digital signal sequence to be transmitted by each of the transmitting devices, and arranging the digital signal sequences to be transmitted by the transmitting devices in a frequency axis direction in which an inverse fast Fourier transform is performed, and performing coding.

Abstract: A MIMO communication method for performing MIMO communication between a base station including a plurality of antennas, and a plurality of terminals accommodated in the base station. The method includes, in the base station, dividing the plurality of terminals into a first and a second group, and assigning orthogonal codes with each other to the respective groups, spreading transmission data to the plurality of terminals with the assigned codes, multiplying data obtained by the spreading by a predetermined pre-coding matrix, obtaining a channel matrix representing channels between the plurality of antennas and the plurality of terminals, multiplying data obtained by the multiplying by the pre-coding matrix by a complex conjugate matrix of the channel matrix, and transmitting data obtained by the multiplying by the complex conjugate matrix from the plurality of antennas.

Abstract: A device includes circuitry configured to spread one or more symbols with one or more orthogonal codes into spread signals having a predetermined number of bits. The amplitude of the spread signals is modified via one or more layer coefficients and the spread signals are multiplexed into a layered transmit signal.

Abstract: A MIMO communication method for performing MIMO communication between a base station including a plurality of antennas, and a plurality of terminals accommodated in the base station. The method includes, in the base station, dividing the plurality of terminals into a first and a second group, and assigning orthogonal codes with each other to the respective groups, spreading transmission data to the plurality of terminals with the assigned codes, multiplying data obtained by the spreading by a predetermined pre-coding matrix, obtaining a channel matrix representing channels between the plurality of antennas and the plurality of terminals, multiplying data obtained by the multiplying by the pre-coding matrix by a complex conjugate matrix of the channel matrix, and transmitting data obtained by the multiplying by the complex conjugate matrix from the plurality of antennas.

Abstract: A Multi-Input Multi-Output base station includes a plurality of transmitter blocks. Each block includes a time-domain base band signal source circuit that generates an output, a low pass filter circuit coupled to the base band source circuit that filters the output of the base band source circuit, and a signal level adjuster circuit coupled to the base band signal source circuit and the low pass filter and that adjusts the output of the base band signal source circuit based on an output of the low pass filter.

Abstract: A MIMO communication method for performing MIMO communication between a base station including a plurality of antennas, and a plurality of terminals accommodated in the base station. The method includes, in the base station, dividing the plurality of terminals into a first and a second group, and assigning orthogonal codes with each other to the respective groups, spreading transmission data to the plurality of terminals with the assigned codes, multiplying data obtained by the spreading by a predetermined pre-coding matrix, obtaining a channel matrix representing channels between the plurality of antennas and the plurality of terminals, multiplying data obtained by the multiplying by the pre-coding matrix by a complex conjugate matrix of the channel matrix, and transmitting data obtained by the multiplying by the complex conjugate matrix from the plurality of antennas.

Abstract: A MIMO communication method of performing MIMO communication between a base station having a plurality of antennas and each of a plurality of terminals covered by the base station using uplink data slots and downlink data slots that are alternately placed on a time axis. The method includes, in the base station, despreading a received signal that is transmitted from each of the plurality of terminals demodulating the transmission data transmitted from a respective terminal on the basis of the value of the estimated channel; decoding a received signal included in the uplink data slots, estimating a current channel between each of all antennas of the base station and the respective terminal; and comparing the stored value of the estimated channel with a value of the estimated current channel and updating the stored value of the estimated channel to the value of the estimated current channel.

Abstract: A device includes circuitry configured to spread one or more symbols with one or more orthogonal codes into spread signals having a predetermined number of bits. The amplitude of the spread signals is modified via one or more layer coefficients and the spread signals are multiplexed into a layered transmit signal.

Abstract: A MIMO communication method for performing MIMO communication between a base station including a plurality of antennas, and a plurality of terminals accommodated in the base station. The method includes, in the base station, dividing the plurality of terminals into a first and a second group, and assigning orthogonal codes with each other to the respective groups, spreading transmission data to the plurality of terminals with the assigned codes, multiplying data obtained by the spreading by a predetermined pre-coding matrix, obtaining a channel matrix representing channels between the plurality of antennas and the plurality of terminals, multiplying data obtained by the multiplying by the pre-coding matrix by a complex conjugate matrix of the channel matrix, and transmitting data obtained by the multiplying by the complex conjugate matrix from the plurality of antennas.

Abstract: A device includes circuitry configured to spread one or more symbols with one or more orthogonal codes into spread signals having a predetermined number of bits. The amplitude of the spread signals is modified via one or more layer coefficients and the spread signals are multiplexed into a layered transmit signal.

Abstract: A MIMO communication method of performing MIMO communication between a base station having a plurality of antennas and each of a plurality of terminals covered by the base station using uplink data slots and downlink data slots that are alternately placed on a time axis. The method includes, in the base station, despreading a received signal that is transmitted from each of the plurality of terminals demodulating the transmission data transmitted from a respective terminal on the basis of the value of the estimated channel; decoding a received signal included in the uplink data slots, estimating a current channel between each of all antennas of the base station and the respective terminal; and comparing the stored value of the estimated channel with a value of the estimated current channel and updating the stored value of the estimated channel to the value of the estimated current channel.

Abstract: A Multiple Input Multiple Output (MIMO) communication method and system for performing communication between N (N is an integer greater than or equal to 2) transmitting devices each having a transmit antenna and at least one receiving device having N receive antennas by using a multi-user MIMO scheme. The method includes dividing the N transmitting devices into a plurality of sets, and assigning an orthogonal code to each set of transmitting devices as a digital signal sequence to be transmitted by each of the transmitting devices, and arranging the digital signal sequences to be transmitted by the transmitting devices in a frequency axis direction in which an inverse fast Fourier transform is performed, and performing coding.

Abstract: A Multiple Input Multiple Output (MIMO) communication method and system for performing communication between N (N is an integer greater than or equal to 2) transmitting devices each having a transmit antenna and at least one receiving device having N receive antennas by using a multi-user MIMO scheme. The method includes dividing the N transmitting devices into a plurality of sets, and assigning an orthogonal code to each set of transmitting devices as a digital signal sequence to be transmitted by each of the transmitting devices, and arranging the digital signal sequences to be transmitted by the transmitting devices in a frequency axis direction in which an inverse fast Fourier transform is performed, and performing coding.

Abstract: A Multiple Input Multiple Output (MIMO) communication method and system for performing communication between N (N is an integer greater than or equal to 2) transmitting devices each having a transmit antenna and at least one receiving device having N receive antennas by using a multi-user MIMO scheme. The method includes dividing the N transmitting devices into a plurality of sets, and assigning an orthogonal code to each set of transmitting devices as a digital signal sequence to be transmitted by each of the transmitting devices, and arranging the digital signal sequences to be transmitted by the transmitting devices in a frequency axis direction in which an inverse fast Fourier transform is performed, and performing coding.

Abstract: A MIMO communication method of performing MIMO communication between a base station having a plurality of antennas and each of a plurality of terminals covered by the base station using uplink data slots and downlink data slots that are alternately placed on a time axis. The method includes, in the base station, despreading a received signal that is transmitted from each of the plurality of terminals demodulating the transmission data transmitted from a respective terminal on the basis of the value of the estimated channel; decoding a received signal included in the uplink data slots, estimating a current channel between each of all antennas of the base station and the respective terminal; and comparing the stored value of the estimated channel with a value of the estimated current channel and updating the stored value of the estimated channel to the value of the estimated current channel.

Abstract: A base station that includes a data control circuitry that processes a transmission signal to be simultaneously transmitted to a plurality of mobile terminals; a modulator circuitry that modulates the transmission signal processed by the data control circuitry; a radio frequency modulator circuitry that modulates the transmission signal modulated by the modulator circuitry into a radio frequency transmission signal; and a plurality of antennas that wirelessly transmit the radio frequency transmission signal to the plurality of mobile terminals. In a case that the number of the plurality of mobile terminals to which the transmission signal is to be transmitted is Nv and the number of the plurality of antennas is Nb, the data control circuitry multiplies the transmission signal by a precode matrix.

Abstract: A Multi-Input Multi-Output base station includes a plurality of transmitter blocks. Each block includes a time-domain base band signal source circuit that generates an output, a low pass filter circuit coupled to the base band source circuit that filters the output of the base band source circuit, and a signal level adjuster circuit coupled to the base band signal source circuit and the low pass filter and that adjusts the output of the base band signal source circuit based on an output of the low pass filter.

Abstract: To suppress noise generation in a wide band and to suppress a clock speed from being increased in a sigma-delta modulation apparatus and a sigma-delta modulation power amplifier. A sigma-delta modulator creates a sigma-delta modulated signal for a digital output from a digital modulator, according to a clock given in advance. A threshold comparator indexes a portion in which the level of a digital output from the digital modulator is higher than a predetermined threshold and sends the resulting output. A replacing unit replaces the indexed portion with an output from a corresponding thinning unit. A filter unit performs band elimination filter processing on an output from the replacing unit and a digital-to-analog converter (D/A) performs digital-to-analog conversion on an output from the filter unit.

Abstract: An electronic device that digitizes a baseband signal obtained from a received high-frequency signal; specifies a position of a preamble included in the digitalized signal; calculates a square of the preamble; specifies a peak from a value obtained by the square of the preamble; performs a fast Fourier transform (FFT) on the baseband signal using a position of the peak as a start of an FFT window; extracts phases of a plurality of frequency components for phase measurement from the baseband signal which has been subjected to the FFT; obtains a phase difference of the plurality of phases; and obtains a phase correction value of a reception signal using the phase difference and a phase reference.