Patent application number | Description | Published |
20080207270 | Method for Generating Downlink Beamforming Weighting Vectors - Techniques are provided for generating downlink beamforming weighting vectors by using channel information about one or more uplink sub-channels in a wireless communications network in the case of frequency mismatch between downlink channels and uplink channels for a specific user. The method comprises calculating an average channel covariance matrix of one or more uplink sub-channels assigned to a specific user, dividing a sector of a cell into a plurality of sub-sectors, transforming the average channel covariance matrix into a plurality of average sub-sector channel covariance matrices and obtaining an average uplink beamforming weighting vector group corresponding to the plurality of sub-sectors, selecting direction of arrival (DOA) sub-sectors from the plurality of sub-sectors by using the plurality of average sub-sector channel covariance matrices, and computing a time delay sequence for the DOA sub-sectors, and generating downlink beamforming weighting vectors by using the average uplink beamforming weighting vectors corresponding to the DOA sub-sectors and the information derived from the time delay sequence. | 08-28-2008 |
20090022254 | PHYSICAL CARRIER TO INTERFERENCE-PLUS-NOISE RATIO TECHNIQUES FOR WIDEBAND WIRELESS COMMUNICATION NETWORKS - Techniques are provided to compute the physical carrier to interference-plus-noise ratio (PCINR) in a wireless communication system. In one embodiment, the PCINR is computed from received signals in active subcarriers in a preamble of a wireless transmission frame. In another embodiment, the PCINR is computed from a block of contiguous subcarriers in a symbol of received wireless transmission. The PCINR may be used to adjust a system parameter associated with wireless communication between wireless communication devices. | 01-22-2009 |
20090051594 | Low Complexity Blind Beamforming Weight Estimation - Techniques are provided to compute beamforming weights at a communication device, e.g., a first communication device, based on transmissions received at a plurality of antennas from another communication device, e.g., a second communication device. A plurality of transmissions are received at the plurality of antennas of the first communication device from the second communication device. A covariance matrix associated with reception of a plurality of transmissions at the plurality of antennas of the first communication device is computed. Corresponding elements (e.g., all the rows or all the columns) of the covariance matrix are combined to produce a weighted channel signature vector. A receive beamforming weight vector is computed from the weighted channel signature vector. | 02-26-2009 |
20090080560 | CLOSED-LOOP BEAMFORMING WEIGHT ESTIMATION IN FREQUENCY DIVISION DUPLEX SYSTEMS - A closed-loop beamforming weight estimation process in which, at a first device, respective ones of a plurality of beamforming weight vectors are applied to subcarriers associated with a pattern of subcarriers assigned to a corresponding subcarrier stream such that the plurality of subcarriers assigned to a subcarrier stream is weighted by a corresponding one of the plurality of beamforming weight vectors to produce a plurality of beamformed streams transmitted from a plurality of antennas of the first device to a second device. The second device estimates and analyzes the channel information for each of the received beamformed streams to identify at least one of the beamformed streams that is preferred over the others. The second device transmits to the first device a feedback signal that contains information identifying the preferred beamformed stream. The first device computes a plurality of new beamforming weight vectors based on the information identifying the preferred beamformed stream. The first device applies the new beamforming weight vectors to streams of subcarriers to repeat the process until system parameters or conditions are met. | 03-26-2009 |
20090088090 | OMNI-DIRECTIONAL AND LOW-CORRELATED PRE-CODING BROADCAST BEAMFORMING - Techniques are provided herein to compute beamforming weight vectors for pre-coding broadcast signals. First, system parameters for a device configured to wirelessly transmit one or more broadcast signals via a plurality of antennas are determined. Based on the system parameters a plurality of beamforming weight vectors are computed. The beamforming weight vectors are computed such that they have omni-directional like characteristics and such that correlation between beamforming weight vectors is relatively low. The plurality of beamforming weight vectors are applied to each of the one or more broadcast signals for transmission by the device to produce beamformed transmit signals for transmission via the plurality of antennas. | 04-02-2009 |
20090270118 | Frequency Band Extrapolation Beamforming Weight Computation for Wireless Communications - Techniques are provided to facilitate the computation of beamforming weights used by a first communication device when sending a transmission via a plurality of antennas to a second communication device where knowledge of the behavior of the channel between the first communication device and the second communication device is limited to a portion of a wide frequency band. A frequency extrapolation beamforming weight computation process is provided to derive knowledge in other frequency subbands based on information contained in the received transmission from the second communication device. | 10-29-2009 |
20090322614 | ORTHOGONAL/PARTIAL ORTHOGONAL BEAMFORMING WEIGHT GENERATION FOR MIMO WIRELESS COMMUNICATION - Techniques are provided for computing beamforming weight vectors useful for multiple-input multiple-output (MIMO) wireless transmission of multiple signals streams from a first device to a second device. The techniques involve computing a plurality of candidate beamforming weight vectors based on the one or more signals received at the plurality of antennas of the first device. A sequence of orthogonal/partially orthogonal beamforming weight vectors are computed from the plurality of candidate beamforming weight vectors. The sequence of orthogonal/partially orthogonal beamforming weight vectors are applied to multiple signal streams for simultaneous transmission to the second device via the plurality of antennas of the first device. | 12-31-2009 |
20090323847 | OPEN-LOOP BEAMFORMING MIMO COMMUNICATIONS IN FREQUENCY DIVISION DUPLEX SYSTEMS - Techniques are provided for wireless communication between a first wireless communication device and a second wireless communication device. At a plurality of antennas of the first wireless communication device, one or more signals transmitted by a second wireless communication device in a first frequency band are received. Beamforming weights are computed from information derived from the signals received at the plurality of antennas using one or more of a plurality of methods without feedback information from the second wireless communication device about a wireless link from the first wireless communication device to the second wireless communication device. The beamforming weights are applied to at least one transmit signal to beamform the at least one transmit signal for transmission to the second wireless communication device in a second frequency band. | 12-31-2009 |
20100157861 | BEAMFORMING SPATIAL DE-MULTIPLEXING FOR COLLABORATIVE SPATIALLY MULTIPLEXED WIRELESS COMMUNICATION - Techniques are provided herein to enable collaborative spatial multiplexing in a wireless communication system. At M plurality of antennas of a first wireless communication device, N plurality of spatially multiplexed transmissions are received from corresponding ones of N plurality of second wireless communication devices. The first wireless communication device produces M receive signals from the transmissions received at the M plurality of antennas. The first wireless communication device applies beamforming weight vectors to the M receive signals and in so doing produces N signals or signal streams, where N is less than or equal to M. The first wireless communication device then recovers the modulated data for each of the transmissions from the N signals. | 06-24-2010 |
20100321237 | Beamforming Techniques to Improve Ranging Signal Detection - Techniques are provided herein to detect ranging codes in energy received at a plurality of antennas of a wireless communication device. Energy is received at a plurality of antennas of a first wireless communication device and received signals are generated from the received energy. The received energy comprises a ranging transmission from one or more second wireless communication devices, wherein each ranging transmission comprises a ranging code selected from a set of possible ranging codes. A ranging code specific receive beamforming weight vector is generated for a ranging code in the set of possible ranging codes from the received signals. The ranging code specific receive beamforming weight vector is applied to corresponding ranging code specific signals derived from the received signals to produce ranging code specific beamformed signals. The ranging code specific beamformed signals are correlated to produce correlation results. A determination is made as to whether the ranging code is present in the received energy based on the correlation results. | 12-23-2010 |
20110012787 | Combined Beamforming and Nulling to Combat Co-Channel Interference - Techniques are provided to improve receive beamforming at a wireless communication device that receives energy in a frequency band at M plurality of antennas, where the received energy includes desired signals and interference signals. The wireless communication device has no knowledge of the spatial signatures of the desired signals and interference signals. A weighted sum signal vector is computed from the received signals and a covariance matrix is computed from the receive signals. Eigenvalue decomposition of the covariance matrix is computed to obtain M eigenvalues of corresponding M eigenvectors of the covariance matrix. A correlation rate is computed between the M eigenvectors and the weighted sum signal vector. A combined receive beamforming and nulling weight vector is computed from the M eigenvectors and the weighted sum signal vector and based further on the correlation rate. The combined receive beamforming and nulling weight vector is applied to the received signals so as to receive beamform the desired signals and null out the interference signals. | 01-20-2011 |
20110045792 | Beamforming Weight Generation Using Adaptive Trigonometric Waveform Interpolation Techniques - Techniques are provided herein to generate beamforming weight vectors for transmissions to be made from a first wireless communication device, e.g., a base station, to a second wireless communication device, e.g., a client device. The first device has a plurality of antennas and receives uplink transmissions from the second device, each uplink transmission comprising a group of frequency subcarriers. The first device computes channel information from the received uplink transmission and computes one or more trigonometric waveforms determined to approximate the channel information. One or more downlink beamforming weight vectors are computed at any given frequency subcarrier (thus in any frequency subband) by interpolation using the one or more trigonometric waveforms. | 02-24-2011 |
20110124290 | MIMO Mode Switch Management for Beamformed MIMO Systems - Techniques are provided herein for improving multiple-input multiple-output (MIMO) wireless communications, and in particular to dynamically determining when to switch MIMO transmission modes on a communication link between two devices that are capable of supporting multiple MIMO transmission modes. A base station receives from a client device one or more signals containing information representing a first signal-to-noise ratio (SNR) measurement and a second SNR measurement made by the client device. The first SNR measurement is associated with a first MIMO transmission mode and the second SNR measurement is associated with a second MIMO transmission mode. The base station computes a MIMO channel quality indicator from the first SNR measurement and the second SNR measurement, and evaluates the MIMO channel quality indicator to determine whether to switch MIMO transmission modes for transmissions to the client device. | 05-26-2011 |
20140154992 | Explicit and Implicit Hybrid Beamforming Channel Sounding - A channel sounding scheme is presented herein that relies on a combination of a first channel sounding procedure and a second channel sounding procedure. The first channel sounding technique is one that involves an exchange of dedicated channel sounding related signals to determine channel conditions between the first wireless communication device and the particular second wireless communication device. The second channel sounding technique is one in which channel conditions are implicitly discovered from any signals transmitted by the particular second wireless communication device to the first wireless communication device. A first wireless communication device computes updates to steering matrix information used for beamforming one or more signal streams to a particular second wireless communication device based on a combination of the first channel sounding technique and the second channel sounding technique. | 06-05-2014 |