Abstract: Methods are provided for mitigating interference due to pilot contamination in a cellular network in which there is reuse of pilot signals. In embodiments, forward-link signals are precoded, using knowledge of slow-fading coefficients, to mitigate the interference. In embodiments, interference in reverse-link signals destined for a given base station is mitigated by linearly combining reverse-link signals destined for the given base station and for other base stations of the network, using knowledge of slow-fading coefficients.

Abstract: Embodiments are described to mitigate network interference issues and to enable a significant increase in the throughput of wireless systems. In one method, pilot transmissions of a first and second group of wireless units are synchronized. Each wireless unit of the first group and each wireless unit of the second group use a different orthogonal pilot (than others in their group) from the same group of orthogonal pilots. Also, the pilot transmissions of the second group of wireless units are synchronized so as to be shifted in time from the pilot transmissions of the first group. In another method, data from neighboring cells and pilots from wireless units are received at a cell. Channel vectors for the wireless units are then estimated using the received data from neighboring cells, the received pilots from the wireless units and previously estimated channel vectors between the cell and the neighboring cells.

Abstract: Embodiments of methods and apparatuses for characterizing an electrical power distribution system are disclosed. One method includes applying, by at least one test/response unit, at least one test signal to at least one test point of the system, measuring, by a plurality of test/response units, a plurality of response signals at a plurality of test points, wherein the plurality of response signals are generated in response to the at least one test signal, and characterizing the system based on the plurality of response signals.

Abstract: A new method is disclosed for providing wireless fixed access from an array of service antennas to a population of local terminals. In implementations, a service transceiver station (STS) performs beamform precoding using channel state information (CSI) obtained from transmissions by the local terminals, and the STS performs power allocation using slow fading coefficients which are static over the service antenna positions and over a frequency range spanning at least some carriers used for downlink transmission.

Abstract: A method is provided, in which a base station allocates pilot signals to mobile terminals in a cell, obtains CSI from uplink pilot signals transmitted by mobile terminals, uses the CSI to precode messages, and transmits the messages in conformance with a TDD protocol. The CSI is obtained by comparing the pilot signal received from each mobile terminal to a known pilot signal associated with that mobile terminal. The known pilot signals are associated with respective mobile terminals according to a pilot signal reuse pattern in which adjacent cells are allocated mutually orthogonal reuse groups of mutually orthogonal pilot signals, and mobile terminals within a given cell are limited to transmitting only pilot signals allocated to that cell.

Abstract: Embodiments provide a MIMO system having a plurality of service antennas and method for data transmission and reception. The system includes a plurality of service antennas, where each service antenna is configured to simultaneously serve a plurality of terminals and independently receive a pilot sequence from the plurality of terminals. The system further includes a plurality of channel estimation units configured to independently generate an antenna-specific channel estimate based on the received pilot sequence and a plurality of pre-coding units configured to independently generate a coded signal to be transmitted to the plurality of terminals via a respective service antenna based on a set of data symbols and the antenna-specific channel estimate.

Abstract: Embodiments provide an apparatus and method for interference alignment for channel-adaptive waveform modulation. The method includes obtaining at least a part of a first matrix and a part of a second matrix for the impulse response function of a communication channel. The method further includes designing a set of one or more linearly independent waveforms based on at least the obtained parts of the first and second matrices such that a first subspace spanned by the linearly independent waveforms when multiplied by the obtained part of the first matrix at least partially overlaps a second subspace spanned by the linearly independent waveforms when multiplied by the obtained part of the second matrix.

Abstract: Embodiments of methods and apparatuses for characterizing an electrical power distribution system are disclosed. One method includes applying, by at least one test/response unit, at least one test signal to at least one test point of the system, measuring, by a plurality of test/response units, a plurality of response signals at a plurality of test points, wherein the plurality of response signals are generated in response to the at least one test signal, and characterizing the system based on the plurality of response signals.

Abstract: A method and apparatus for communication between a wireless base station and a population of one or more terminals are provided, involving, in each of a plurality of iterations, transmitting a block of forward-link data from an array of multiple base station antennas to the terminal population. In each iteration, a forward-link power level is updated for each said terminal using a distributed algorithm and purely local information. Meanwhile, a set of beamforming coefficients based on channel state information (CSI) obtained from reverse-link pilot signals is periodically updated, and each data block is precoded with the most recently updated beamforming coefficients. Each data block is transmitted at the most recently updated forward-link power levels.

Abstract: Methods are provided for mitigating interference due to pilot contamination in a cellular network in which there is reuse of pilot signals. In embodiments, forward-link signals are precoded, using knowledge of slow-fading coefficients, to mitigate the interference. In embodiments, interference in reverse-link signals destined for a given base station is mitigated by linearly combining reverse-link signals destined for the given base station and for other base stations of the network, using knowledge of slow-fading coefficients.

Abstract: Embodiments of methods and apparatuses for characterizing an electrical power distribution system are disclosed. One method includes applying at least one test signal to at least one test point of the system, measuring a plurality of response signals at a plurality of test points, wherein the plurality of response signals are generated in response to the at least one test signal, and characterizing the system based on the plurality of response signals. One system includes a plurality of test/response units attached to a plurality of test points, the units configured to generate test signals and/or measure response signals at the test points. At least one controller coordinates application of the test signals and characterizes the electrical network based on the response signals. A communications link allows the test/response units to communicate with the at least one controller.

Abstract: A communication method uses a distributed cell-free network of spatially independent service antennas. According to the method, pilot sequences are allocated to a user population of access terminals by an allocation procedure that imposes local relative orthogonality of pilot sequences. Channel coefficients for access terminals arc determined by measuring allocated pilot sequences as received by each of the service antennas. In embodiments of the invention, the determination of channel coefficients is performed independently and the resulting channel coefficients are locally stored at the respective service antennas. At each service antenna, a processor independently uses locally stored channel coefficients to precode forward link signals or to at least partially decode reverse link signals.

Abstract: Embodiments provide an apparatus and method for interference alignment for channel-adaptive waveform modulation. The method includes obtaining at least a part of a first matrix and a part of a second matrix for the impulse response function of a communication channel. The method further includes designing a set of one or more linearly independent waveforms based on at least the obtained parts of the first and second matrices such that a first subspace spanned by the linearly independent waveforms when multiplied by the obtained part of the first matrix at least partially overlaps a second subspace spanned by the linearly independent waveforms when multiplied by the obtained part of the second matrix.

Abstract: Embodiments of methods and apparatuses for characterizing an electrical power distribution system are disclosed. One method includes applying a plurality of test signals to a first plurality of test points of the electrical power distribution system, measuring a plurality of response signals at a second plurality of test points of the electrical distribution system, deriving a characterization matrix for the electrical power distribution system from the plurality of test signals and response signals, and characterizing the electrical power distribution system based on the derived characterization matrix.

Abstract: In one embodiment, a wireless power transfer system has a wireless power transmitter and receiver. The transmitter has a transmitting resonant circuit that resonates at a first frequency and a signal generator that generates a signal at a second frequency. The transmitter also has a power detector that measures reflected power at the transmitting resonant circuit, and an auto-tuner that generates transmitter tuning parameters for adjusting the first and second frequencies to reduce reflected power. The receiver has a receiving resonant circuit that resonates at a third frequency based on a receiver tuning parameter. The receiver tuning parameter is generated by a power detector that measures power generated at the receiving resonant circuit, and an auto-tuner that generates the receiver tuning parameter to increase the load power.

Abstract: Embodiments of methods and apparatuses for characterizing an electrical power distribution system are disclosed. One method includes applying at least one test signal to at least one test point of the system, measuring a plurality of response signals at a plurality of test points, wherein the plurality of response signals are generated in response to the at least one test signal, and characterizing the system based on the plurality of response signals. One system includes a plurality of test/response units attached to a plurality of test points, the units configured to generate test signals and/or measure response signals at the test points. At least one controller coordinates application of the test signals and characterizes the electrical network based on the response signals. A communications link allows the test/response units to communicate with the at least one controller.

Abstract: Embodiments provide a MIMO system having a plurality of service antennas and method for data transmission and reception. The system includes a plurality of service antennas, where each service antenna is configured to simultaneously serve a plurality of terminals and independently receive a pilot sequence from the plurality of terminals. The system further includes a plurality of channel estimation units configured to independently generate an antenna-specific channel estimate based on the received pilot sequence and a plurality of pre-coding units configured to independently generate a coded signal to be transmitted to the plurality of terminals via a respective service antenna based on a set of data symbols and the antenna-specific channel estimate.

Abstract: Various embodiments generally relate to a method for synchronizing a receiver, said method including receiving a stream that includes a cyclic extension, estimating a size of the cyclic extension, extracting an amount of the stream according to the estimated size, and comparing the extracted amount to the stream to determine thereby a portion of the stream likely to include a symbol start point.

Abstract: Embodiments are described to mitigate network interference issues and to enable a significant increase in the throughput of wireless systems. In one method, pilot transmissions of a first and second group of wireless units are synchronized. Each wireless unit of the first group and each wireless unit of the second group use a different orthogonal pilot (than others in their group) from the same group of orthogonal pilots. Also, the pilot transmissions of the second group of wireless units are synchronized so as to be shifted in time from the pilot transmissions of the first group. In another method, data from neighboring cells and pilots from wireless units are received at a cell. Channel vectors for the wireless units are then estimated using the received data from neighboring cells, the received pilots from the wireless units and previously estimated channel vectors between the cell and the neighboring cells.

Abstract: In one aspect, a compressive sampling encoder comprises matrix determination circuitry configured to determine a particular sampling matrix selected from a codebook comprising a plurality of sampling matrices. The compressive sampling encoder further comprises sampling circuitry coupled to the matrix determination circuitry and configured to apply the particular sampling matrix to a first signal to generate a second signal, and encryption circuitry configured to receive an identifier of the particular sampling matrix and to encrypt the identifier of the particular sampling matrix. The compressive sampling encoder provides at one or more outputs thereof the second signal and the encrypted identifier of the particular sampling matrix. Other aspects include a compressive sampling decoder, compressive sampling encoding and decoding methods, and associated computer program products.