Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.

A communications device includes a uniform linear array of M antennas and a field programmable gate array (FPGA) having pipelined stages in which execution of overlapping instructions estimate a direction of arrival of RF signals from multiple sources. A preprocessing stage of the FPGA includes at least one configurable logic block configured to apply forward/backward averaging spatial smoothing to a signal space matrix extracted from a covariance matrix in the preprocessing stage. The FPGA further includes at least one configurable logic block configured to compute the direction of arrival angle for the RF signals using a least squares method.

Methods and apparatus are disclosed for searching and tracking intercell interference in communication networks. In an exemplary embodiment, a method is provided that includes operations of receiving a noise covariance matrix and generating a beam sub-space from the noise covariance matrix. The beam sub-space includes one or more sub-space beams. The method also includes determining a set of selected sub-space beams having energy levels that exceed a threshold, calculating an Eigenvector decomposition for the set of selected sub-space beams to identify an Eigenspace of interference energy, and tracking the Eigenspace over time.

Method and UE are provided for determining precoder of MIMO system. In particular, a BS can transmit at least one CSI-RS to the UE. The UE can receive the at least one CSI-RS, and estimate at least one covariance matrix of at least one downlink channel matrix according to the at least one CSI-RS at different times and frequencies. Then, the UE can transmit the at least one covariance matrix or at least one parameter associated with the least one covariance matrix to the BS for the BS to reconstruct at least one covariance matrix, and determine a precoder according to the at least one reconstructed covariance matrix.

A communications device includes a uniform linear array of M antennas and a field programmable gate array (FPGA) having pipelined stages in which execution of overlapping instructions estimate a direction of arrival of RF signals from multiple sources. A preprocessing stage of the FPGA includes at least one configurable logic block configured to apply forward/backward averaging spatial smoothing to a signal space matrix extracted from a covariance matrix in the preprocessing stage. The FPGA further includes at least one configurable logic block configured to compute the direction of arrival angle for the RF signals using a least squares method.

A multiple-input multiple-output (MIMO) mode configuration method is applied to a terminal, and includes: determining a triggering factor, the triggering factor including terminal information that triggers MIMO mode adjustment; sending a first instruction, the first instruction being used for requesting a network device to configure an MIMO mode matched with the triggering factor for the terminal; and obtaining a second instruction, the second instruction being used for representing the MIMO mode configured by the network device for the terminal.

A method of transmitting a plurality of data streams across a MIMO channel from a transmitter to a receiver, the transmitter comprising an array of antennas, the method comprising acquiring channel state information for a plurality of subcarrier frequencies, determining a mapping that defines, for each frequency, how each data stream is to be mapped to each antenna in the array, and for each antenna in the array, adjusting the power allocated to each data stream that is to be transmitted from the antenna, so as to maximise a measure of throughput; wherein for each data stream, the power allocated to transmitting that data stream at each frequency is greater than or equal to zero, and for each frequency, the power transmitted by any one antenna does not exceed a threshold, and for each data stream, the same power is allocated to each subcarrier used for transmitting that data stream.

A method of transmission over multiple wireless channels in a multiple antenna system includes storing channel modulation matrices at a transmitter; receiving quantized channel state information at the transmitter from plural receivers; selecting a transmission modulation matrix using the quantized channel state information from the stored channel modulation matrices; and transmitting over the multiple channels to the plural receivers using the selected transmission modulation matrix. In another embodiment, the method includes storing, at one or more receivers, indexes of modulation matrices generated by a capacity enhancing algorithm; upon a selected one of the one or more receivers receiving a transmission from the transmitter, the selected receiver selecting a modulation matrix from the stored modulation matrices that optimizes transmission between the transmitter and the selected receiver; the selected receiver sending an index representing the selected modulation matrix; and receiving the index at the transmitter from the selected receiver.

A system includes first and second sets of communication devices. A processor coupled to the first set of communication devices produces a first encoded vector and transmits the first encoded vector to the second set of communication devices via a communication channel that applies a channel transformation to the first encoded vector during transmission. A processor coupled to the second set of communication devices receives the transformed signal, detects an effective channel thereof, and identifies left and right singular vectors of the effective channel. A precoding matrix is selected from a codebook of unitary matrices based on a message, and a second encoded vector is produced based on a second known vector, the precoding matrix, a complex conjugate of the left singular vectors, and the right singular vectors. The second encoded vector is sent to the first set of communication devices for identification of the message.

The disclosure relates to an audio processing apparatus for localizing an audio source. The audio processing apparatus comprises a plurality of audio sensors, including a primary audio sensor and at least two secondary audio sensors, configured to detect an audio signal from a target audio source, wherein the primary audio sensor defines at least two pairs of audio sensors with the at least two secondary audio sensors; and processing circuitry configured to: determine for each pair of audio sensors a first set of likelihoods of spatial directions of the target audio source using a first localization scheme; determine a second set of likelihoods of spatial directions of the target audio source using a second localization scheme; and determine a third set of likelihoods of spatial directions of the target audio source on the basis of the first sets of likelihoods and the second set of likelihoods.