Patent application number | Description | Published |
20120127929 | De-Correlation of Sub-Bands Using Cyclic Shifts - Techniques are provided to de-correlate sub-bands of a packet to be transmitted. At a communication device, a signal (packet or frame) is generated for transmission. The packet or frame comprises a plurality of subcarriers in each of a plurality of sub-bands. Different cyclic delays are applied to the plurality of sub-bands of the signal. The signal is amplified after applying the different cyclic delays for transmission from the communication device. | 05-24-2012 |
20120264388 | Adaptive Interference Nulling for MIMO Receiver Based on Interference Characteristics - Interference in an unlicensed frequency band is spatially filtered out from received signals at a wireless device operating in the unlicensed frequency band. Energy received at a plurality of antennas of the wireless is device is analyzed to detect interference in the unlicensed frequency band. The detected interference is classified by type. Parameters for a nulling filter are generated or selected based on the type of interference detected in the received energy. During a time interval when it is expected to receive desired signals, the nulling filter is applied using the parameters to signals obtained from energy received at the plurality of antennas during the time interval. | 10-18-2012 |
20120328033 | Implicit Spatial Matrix Expansion Determination for MIMO Wireless Communication Systems - Techniques are provided to allow for implicit determination of the full spatial signature of a wireless channel between first and second wireless devices for multiple-input multiple-output (MIMO) wireless communication between the first and second wireless devices. The first wireless device receives uplink signals at a plurality of antennas of the first wireless device that are transmitted via a plurality of antennas of a second wireless device. Values at a plurality of subcarriers of the received signals across the plurality of antennas of the first wireless device are derived. Using a sliding window for groups of adjacent subcarriers, downlink beamforming weights are computed for each group of subcarriers using channel information of one or more proximate groups of subcarriers. The downlink beamforming weights for the respective groups of subcarriers are applied to a number of spatial streams in a downlink transmission to be transmitted to the second wireless device. | 12-27-2012 |
20130012134 | Dynamic Clear Channel Assessment Using Spectrum Intelligent Interference Nulling - At a wireless device operating in an unlicensed frequency band, energy received at a plurality of antennas is analyzed to detect interference on a channel in the unlicensed frequency band. The type of interference detected in the received energy is determined. Parameters are then generated for a nulling filter based on the type of interference detected in the received energy. The nulling filter is applied to the received energy at the plurality of antennas to produce a spatially filtered output. The spatially filtered output is evaluated to determine whether to send a transmission on the channel in the unlicensed frequency band. | 01-10-2013 |
20130128935 | FULL SPATIAL DIMENSION EXTRACTION FOR IMPLICIT BEAMFORMING - Techniques are provided to compute downlink beamforming weights for beamforming multiple spatial streams to a wireless device when that wireless device does not transmit with a maximum number of spatial streams, and thus when the full dimensional knowledge of the wireless channel to that wireless device needs to be implicitly derived. Uplink signals are received at a plurality of antennas of a first wireless device that are transmitted via a plurality of antennas of a second wireless device. The first wireless device derives values at a plurality of subcarriers of the received signals across the plurality of antennas of the first wireless device. Downlink beamforming weights are computed from values of consecutive subcarriers across the plurality of antennas of the first wireless device. The first wireless device applies the downlink beamforming weights at respective subcarriers to a number of spatial streams to be transmitted to the second wireless device. | 05-23-2013 |
20130286863 | Uplink Signal Bandwidth Characterization from Channel State Information - Techniques are provided to determine whether or not incident power at a wireless communication device in at least two frequency channels is from the same device. Incident power in frequency channels allocated to a basic service set in a wireless network is received at a plurality of antennas of the wireless communication device. Channel state information is computed for at least two frequency channels allocated to the basic service set. One or more metrics are generated based on the channel state information in the two frequency channels. The one or more metrics are evaluated to characterize an uplink signal bandwidth associated with the two channels to determine whether or not the incident power in the two channels is from the same device. | 10-31-2013 |
20140098681 | High Density Deployment Using Transmit or Transmit-Receive Interference Suppression with Selective Channel Dimension Reduction/Attenuation and Other Parameters - In a wireless local are network, each of multiple access points, in a high density deployment, are configured to suppress co-channel interference. A first access point having a plurality of antennas beamforms a transmission to a wireless client device within a null-space or with the weakest singular eigenmodes of a wireless channel between the first access point and at least one co-channel second access point. Techniques are presented herein for situations in which any given access point has two or more co-channel access points. In addition, an access point may perform receive side suppression with respect to a transmission (made by a co-channel access point to one of its associated wireless client devices) that is received from that co-channel access point. | 04-10-2014 |
20140140438 | Transmit Correlated Array Gain Reduction - Techniques are presented herein to achieve reduced array gain associated with a transmission made from multiple antennas of a wireless communication device. In accordance with one technique, a wireless communication device is provided having a plurality of transmitters each configured to transmit via a corresponding one of a plurality of antennas. Subcarriers of at least one transmit signal to be weighted across the plurality of transmitters are allocated power so that for each subcarrier, only one transmitter is allocated a maximum power. | 05-22-2014 |
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 |
20140241240 | Distributed Processing Distributed-Input Distributed-Output (DIDO) Wireless Communication - Techniques are presented for distributed processing Distributed-Input Distributed-Output (DIDO) wireless communication. A plurality of base stations (e.g., APs) are provided, each configured to wirelessly serve one or more wireless devices (e.g., clients). At least first and second base stations are configured to transmit simultaneously at an agreed upon time. The first and second base stations are each configured to locally generate steering matrix information used to spatially precode their respective data transmissions in order to steer their respective data transmissions to their one or more wireless devices while nulling to the one or more client devices of the other base station. Moreover, the first and second base stations are each configured to locally generate a transmit waveform by applying the steering matrix information to their respective data transmissions. | 08-28-2014 |
20140327579 | ANGLE OF ARRIVAL LOCATION SENSING WITH ANTENNA ARRAY - In one embodiment, an apparatus includes a plurality of antennas, a receiver in communication with said plurality of antennas for receiving one or more packets in a block based modulation environment, a switch interposed between a portion of the antennas and the receiver for switching between the antennas, and a processor for calculating angle of arrival for use in identifying a location of a mobile device transmitting the one or more packets. | 11-06-2014 |
20140328247 | Explicitly Sounding Beyond the Beamformee Sounding Capability - A first device explicitly sounds a wireless channel with respect to a second device even when the second device cannot sound all the antenna/transmit paths of the first device. The first device has a first plurality of antennas and corresponding transmitters and the second device has a second plurality antennas and corresponding receivers. The first device wirelessly transmits a plurality of sounding frames to the second device such that at least one of the first plurality of antennas is kept constant across the plurality of sounding frames. The first device receives from the second device at least one feedback message containing channel matrix information derived from reception of the sounding frames at the second plurality of antennas of the second device. The first device derives a full wireless channel estimate between the first plurality of antennas of the first device and the second plurality of antennas of the second device. | 11-06-2014 |