Patent application number | Description | Published |
20080205539 | Method and System for Achieving Spatial Diversity of a Wireless Communications Network - A method and system are provided for achieving spatial diversity of a wireless communications network. The method comprises arranging antennas on a transmitting wireless station into a plurality of antenna subgroups, wherein each of the antenna subgroups forms a virtual antenna, creating a plurality of beamformed MIMO channels using the plurality of virtual antennas, wherein each of the beamformed MIMO channel comprises a plurality of sub-carriers and corresponds to a virtual antenna, dividing sub-carriers in each of the plurality of beamformed MIMO channels into at least a first and second cluster, distributing a first amount of transmitting power to the first cluster and a second amount of transmitting power to the second cluster, wherein the first amount of transmitting power is substantially larger than the second amount of transmitting power. | 08-28-2008 |
20080240208 | Adaptive Switching Techniques for Hybrid Automatic Repeat Request Systems - Apparatus, system, and method for an adaptive transmission selection technique. A retransmission scheme is selected for a multiple-input-multiple-output (MIMO) wireless communications system. Techniques are provided herein for selecting from a plurality of wireless communication techniques when a first device needs to retransmit a signal (one or more packets of data) to a second device. The first device determines when the signal which was originally wirelessly transmitted using beamforming techniques via multiple antennas of the first device to the second device needs to be retransmitted to the second device. If a retransmission is needed, the first device determines channel conditions with respect to the second device. The first device selects a retransmission scheme from a plurality of transmission schemes based on the channel conditions for retransmitting the signal via the multiple antennas of the first device to the second device. A first retransmission technique is selected when the channel conditions are static. A second retransmission technique is selected when the channel conditions are relatively slowly changing, and a third retransmission technique is selected when the channel conditions are relatively quickly changing. | 10-02-2008 |
20080320355 | System for Identifying Localized Burst Errors - A system for detecting one or more localized burst errors in a receiving message comprised of a plurality of codewords. The system comprises a trellis code decoder for decoding a receiving message with a plurality of codewords and calculating one or more cumulative metrics of a maximum likelihood path and one or more alternative paths from the receiving message, an error detection code (EDC) decoder for detecting existence of one or more errors in the decoded receiving message received from the trellis decoder, and a localized burst error detector activated by the EDC decoder upon detecting the existence of one or more errors in the decoded receiving message to identify at least one corrupted codeword among the plurality of codewords using the one or more cumulative metrics of a maximum likelihood path and the one or more alternative paths, wherein the system requests the re-transmission of the corrupted codeword. | 12-25-2008 |
20090042618 | GENERALIZED MIMO-BEAMFORMING WEIGHT ESTIMATION - Techniques are provided to enable wireless communication between first and second wireless communication devices each having a plurality of antennas, where the second device sends the transmissions via less than all of its plurality of antennas. Each transmission may comprise a plurality of time-frequency instances. At the first communication device, data is derived representing parameters of a communication channel between the plurality of antennas of the first device and all of the plurality of antennas of the second device from the transmissions received at the plurality of antennas of the first device. Beamforming weights for transmitting one or more signal streams via the plurality of antennas of the first device to the plurality of antennas of the second device are computed based on the data representing parameters of the communication channel between the plurality of antennas of the first device and the plurality of antennas of the second device. The beamforming weights are applied to the one or more signal streams to be transmitted via the plurality of antennas of the first device to the plurality of antennas of the second device. | 02-12-2009 |
20090086855 | LINK ADAPTATION BASED ON GENERIC CINR MEASUREMENT ACCORDING TO LOG-LIKELIHOOD RATIO DISTRIBUTION - Techniques are provided to compute the carrier to interference-plus-noise ratio (CINR) in a wireless communication system using log-likelihood ratio (LLR) data generated from a received transmission. The LLR data are collected as they are sent from a detector to a forward error correction (FEC) decoder in a wireless communications device. In one embodiment, decision-aided LLR based CINR is computed using the decoded bits output from the FEC decoder as feedback. In another embodiment, blind LLR based CINR is computed without feedback. The CINR may be used to adjust a modulation and/or coding parameters associated with wireless communication between wireless communication devices. | 04-02-2009 |
20090102715 | Beamforming Multiple-Input Multiple-Output Hybrid Automatic Repeat Request Retransmission - Techniques are provided for improving hybrid automatic repeat request retransmissions techniques in a beamformed multiple-input multiple-output wireless communication environment. At a first device comprising a first plurality of antennas, a plurality of beamforming weight vectors are applied to a corresponding plurality of signal streams for simultaneous transmission to a second device having a plurality of antennas. A determination is made whether the plurality of signal streams need to be retransmitted from the first device to the second device. When a retransmission needs to be made, an order in which the plurality of beamforming weight vectors are applied to the plurality of signal streams is switched for a retransmission attempt of the plurality of signal streams from the first device to the second device. | 04-23-2009 |
20090268695 | Method and System for Processing Reference Signals in OFDM Systems Using Transmission Time Interval Groupings - A method and system processes reference signals ( | 10-29-2009 |
20100189199 | Log-likelihood ratio algorithm for use in reducing co-channel interference in wireless communication systems - In one embodiment, an apparatus includes a receiver configured to receive a transmission from a wireless communication device, the transmission associated with resource units, a detector configured to generate log-likelihood ratio data from the received transmission, and a controller configured to calculate noise and interference for each of the resource units and modify the generated log-likelihood ratio data based on the calculated noise and interference. | 07-29-2010 |
20100238797 | Adaptive Subchannel Disabling in Beamformed Wireless Communication Systems - Techniques are provided herein to adaptively and independently disable use of subchannels in transmission sent from a first wireless communication device to a second wireless communication device. The first wireless communication device receives transmission sent to it by the second wireless communication device. The transmissions occupy some or all of a plurality of subchannels within a frequency band that are available for use in the transmission. The transmissions received at the first wireless communication device are evaluated in each subchannel for an over-the-air wireless link between the first wireless communication device and the second wireless communication device. Based on the evaluation, zero or more of the plurality of subchannels are independently disabled in transmissions that are sent by the first wireless communication device to the second wireless communication device. | 09-23-2010 |
20110105172 | Adaptive Power Balancing and Phase Adjustment for MIMO-Beamformed Communication Systems - Techniques are provided for improving performance of a multiple-input multiple-output (MIMO) wireless communication system. At a first wireless communication device (e.g., a base station) having a plurality of antennas, uplink transmissions are received from a second wireless communication device (e.g., a client device). The base station determines a measure of multipath conditions between it and the second wireless communication device based on the received uplink transmissions. The base station applies downlink beamforming weight vectors together with power balance and phase adjustment factors depending on the measure of multipath conditions to transmit multiple downlink data streams across the plurality of antennas simultaneously to the second wireless communication device. | 05-05-2011 |