| Patent application number | Description | Published |
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| 20080219373 | CODEBOOK SELECTION FOR TRANSMIT BEAMFORMING - A method select a codebook for transmit beamforming. The method constructs an estimated channel matrix based on a codebook, selects a channel submatrix from the estimated channel matrix, calculates a selection matrix from the channel submatrix; and assigns a steering matrix based on the selection matrix. There may be multiple codebooks and the method may construct an estimated channel matrix, select a channel submatrix, and calculate a selection matrix for each of the codebooks, then select an optimal codebook. The steering matrix is assigned based on the optimal codebook. The steering matrix may be used in steering a transmitted packet. The method may also calculate a post-MIMO equalizer signal-to-noise ratio for a data stream, based on the estimated channel matrix and the selected codebook. A related system is also disclosed. Other embodiments are provided, and each of the embodiments described herein can be used alone or in combination with one another. | 09-11-2008 |
| 20080260002 | ANTENNA SELECTION AND TRAINING USING A SPATIAL SPREADING MATRIX FOR USE IN A WIRELESS MIMO COMMUNICATION SYSTEM - A wireless communication system and method uses a spatial spreading matrix to distribute the encoded spatial data streams to a number of transmit chains and further uses the spatial spreading matrix for antenna selection computation in a transmitter. The spatial spreading matrix is designed such that a receiver is able to know and utilize the spatial spreading matrix for computing transmission antenna selection, receiver antenna selection and joint transmission/receiving antenna selection. The use of this spatial spreading matrix for antenna selection computation provides increased accuracy in antenna selection for transmission of spatial data streams, where the number of spatial data streams is less than the number of transmit or receive chains between the transmitter and receiver, and the number of transmit or receive chains is less than the corresponding transmission or receiving antennas. | 10-23-2008 |
| 20080266176 | POWER AMPLIFIER ADJUSTMENT FOR TRANSMIT BEAMFORMING IN MULTI-ANTENNA WIRELESS SYSTEMS - One or more beamsteering matrices are applied to a plurality of signals to be transmitted via multiple antennas. The plurality of signals are provided to a plurality of power amplifiers coupled to the multiple antennas after applying the one or more beamsteering matrices to the plurality of signals. Signal energies are determined for the plurality of signals provided to the plurality of power amplifiers, and output power levels of the plurality of power amplifiers are adjusted based on the determined signal energies. | 10-30-2008 |
| 20080279317 | BICM DECODING IN THE PRESENCE OF CO-CHANNEL INTERFERENCE - Systems and methods are provided for computing soft information for digital information based on a received signal, where the received signal suffers from noise and interference. A receiver that decodes the received signal may estimate channel information, such as the channel gain, associated with the interfering source. The receiver may also obtain modulation information through a backbone network or by decoding control information transmitted by the interfering source. Using the modulation information and the channel information, the receiver may estimate the effect that interference has on the received signal, and may compute soft information (e.g., a log-likelihood ratio) for the digital information. | 11-13-2008 |
| 20090022093 | WIRELESS NETWORK WITH SIMULTANEOUS UPLINK TRANSMISSION OF INDEPENDENT DATA FROM MULTIPLE CLIENT STATIONS - A wireless network comprises R client stations that respectively generate simultaneous uplink transmission (SUT) data, where R is an integer greater than one. An access point (AP) receives SUT data from each of the R client stations during an SUT period. | 01-22-2009 |
| 20090022128 | ACCESS POINT WITH SIMULTANEOUS DOWNLINK TRANSMISSION OF INDEPENDENT DATA FOR MULTIPLE CLIENT STATIONS - A wireless network device comprises R modulation modules that receive R independent data streams, that modulate the R independent data streams, and that apply a multiplexing matrix to generate M modulated and multiplexed data streams, respectively, where R and M are integers greater than one. M summing modules sum portions of each of the M modulated and multiplexed data streams to generate M transmit data streams. M transmitters simultaneously transmit the M transmit data streams during a simultaneous downlink transmission (SDT) period. | 01-22-2009 |
| 20090097395 | Beamforming Using Predefined Spatial Mapping Matrices - Systems and methods for transmitting packets to a receiver. In an implementation, the method includes storing, in a memory, a plurality of predefined spatial mapping matrices for use in a transmission of one or more packets to a receiver; sequentially transmitting one or more packets to the receiver, in which each of the sequential transmissions of one or more packets comprises using a different one of the plurality of predefined spatial mapping matrices stored in the memory; and selecting one of the plurality of predefined spatial mapping matrices stored in the memory for use in a subsequent transmission of one or more packets to the receiver, in which the selection of the one of the plurality of predefined spatial mapping matrices for use in the subsequent transmission is based on a quality of reception of the one or more data packets transmitted in each of the sequential transmissions | 04-16-2009 |
| 20090196372 | Channel Sounding and Estimation Strategies for Antenna Selection in MIMO Systems - Techniques and devices for antenna selection in a multiple-input-multiple-output (MIMO) system, in which communication is between a transmitter having a first plurality of radio-frequency (RF) chains coupled to a first plurality of antennas and a receiver having a second plurality of RF chains coupled to a second plurality of antennas, are provided. Techniques include receiving consecutive sounding packets each have a training symbol and that collectively sound a full-size channel for the MIMO system. A sub-channel estimate for each sounding packet can then be determined based on various factors, such as a known power level rule and gain factor. Scaling factors may be applied to each of these sub-channel estimates to produce a scaled sub-channel estimates. | 08-06-2009 |
| 20090252104 | Physical Layer Frame Format Design for Wideband Wireless Communications Systems - Systems and methods are provided for processing a payload portion of a received signal in a single carrier mode or a multiple carrier mode using a wireless channel receiver based on a portion of the received signal, where a signaling portion of the received signal is a single carrier signal. A single carrier signaling portion is received, and whether the payload portion of the signal is a single carrier signal or a multiple carrier signal is detected from the received single carrier signaling portion. The payload portion of the received signal is demodulated in a single carrier mode if the detecting determines that the payload portion of the received signal is a single carrier signal, and the payload portion of the received signal is demodulated in a multiple carrier mode if the detecting determines that the payload portion of the received signal is a multiple carrier signal. Data from the demodulated payload portion of the received signal is stored in a computer-readable memory. | 10-08-2009 |
| 20090285240 | Efficient Physical Layer Preamble Format - A method of generating a data unit preamble includes generating a first field associated with at least one of packet synchronization information or frame boundary indication, and generating a second field associated with channel estimation, including generating a first channel estimation sequence (CES) symbol and generating a second CES symbol, so that at least one of 1) a sequence in the first field serves as a cyclic prefix of the first CES symbol, 2) a beginning portion of the second CES symbol serves as a cyclic postfix of the first CES symbol, or 3) an ending portion of the first CES symbol serves as a cyclic prefix of the second CES symbol. | 11-19-2009 |
| 20090285241 | Efficient Physical Layer Preamble Format - A method for generating a preamble of a data unit includes generating a short training field (STF) of the preamble to include one of a repeating series of a sequences or a repeating series of b sequences, such that a and b are complementary sequences, a sum of out-of-phase aperiodic autocorrelation coefficients of a and b is zero, and where the STF is associated with at least synchronization information, and generating a long training field (LTF) of the preamble after the STF to include a′ sequences and b′ sequences, such that a′ is the sequence a cyclically shifted by zero or more positions, b′ is the sequence b cyclically shifted by zero or more positions, and where the LTF is associated with channel estimation information. | 11-19-2009 |
| 20090285269 | PHY Preamble Format for Wireless Communication System - A system and method of extracting data from data packets transmitted over a wireless network includes receiving a data packet having a preamble portion and a payload portion. The preamble portion is cross correlated with a first known spreading sequence to generate a first timing signal and the preamble portion is cross correlated with a second known spreading signal to generate a frame timing signal. An impulse is detected in the first timing signal and a first timing parameter is set based upon the detected impulse in the first timing signal. An impulse is detected in the frame timing signal and a frame timing parameter is set based upon the detected impulse in the frame timing signal. Data is extracted from the received payload portion according to the first timing parameter and the frame timing parameter. | 11-19-2009 |
| 20090285319 | Efficient Physical Layer Preamble Format - A method for generating a preamble of a data unit for transmission via a communication channel includes generating a first field of the preamble using one of a first sequence or a second sequence, such that the first sequence and the second sequence are complementary sequences such that a sum of out-of-phase aperiodic autocorrelation coefficients of the first sequence and the second sequence is zero; generating, using the other one of the first sequence or the second sequence, an indicator of a start of a second field of the preamble, the second field associated with channel estimation information, such that the indicator of the start of the second field immediately follows the first field; and generating the second field of the preamble. | 11-19-2009 |
| 20090285339 | Apparatus for Generating Spreading Sequences and Determining Correlation - An apparatus includes a signal generator to output one of a first sequence or a second sequence and to augment sequences with cover codes, such that a sum of out-of-phase aperiodic autocorrelation coefficients of the first sequence and the second sequence of is zero, a physical layer preamble controller to control the signal generator to generate a preamble of a data unit, including a short training field (STF) formatter to cause the signal generator to generate an STF for use in at least frame synchronization, and a long training field (LTF) formatter to cause the signal generator to generate an LTF for use in at least channel estimation, such that the STF formatter controls the signal generator to include the first sequence in a last portion of the STF, and the LTF formatter controls the signal generator to include the second sequence in a beginning portion of the LTF. | 11-19-2009 |
| 20100008436 | Physical Layer Frame Format Design for Wideband Wireless Communications Systems - Systems and methods are provided for processing a payload portion of a received signal in a single carrier mode or a multiple carrier mode based on a portion of the received signal. A single carrier signaling portion is received at a first rate, and whether the payload portion of the signal is a single carrier signal or a multiple carrier signal is detected from the received single carrier signaling portion. The payload portion of the received signal is received at the first rate and demodulated in a single carrier mode if the detecting determines that the payload portion of the received signal is a single carrier signal, and the payload portion of the received signal is demodulated in a multiple carrier mode if the detecting determines that the payload portion of the received signal is a multiple carrier signal. | 01-14-2010 |
| 20100054223 | Physical Layer Data Unit Format - In a wireless communication system wherein communication devices exchange information utilizing data units that conform to a first format, a beamforming training (BFT) data unit that conforms to a second format is transmitted, wherein a length of the BFT data unit is shorter than lengths supported by the first format, wherein the BFT data unit is for transmitting PHY beamforming training information. Information to indicate the BFT data unit conforms to the second format is transmitted to a receiving device. The BFT data unit is generated according to the second format, wherein the BFT data unit includes BFT information elements. The BFT data unit is then transmitted to the receiving device. | 03-04-2010 |
| 20100080266 | Physical Layer Data Unit Format - In a wireless communication system wherein communication devices exchange information utilizing data units that conform to a first format, wherein the first format includes a short training field (STF) spread with a first spread code and a first cover code, a method is for generating a physical layer (PHY) data unit that conforms to a second format, wherein the PHY data unit is for transmitting PHY information. A first portion of the PHY data unit is generated to indicate the PHY data unit conforms to the second format, wherein the first portion of the PHY data unit includes an STF spread with at least one of a second spread code different than the first spread code or a second cover code different than the first cover code. A second portion of the PHY data unit is generated according to the second format, wherein the second portion of the PHY data unit includes PHY information elements not specified by the first format. | 04-01-2010 |
| 20100232475 | Equal Power Output Spatial Spreading Matrix for Use in a Wireless MIMO Communication System - A spatial spreading unit is configured to utilize a spatial spreading matrix to distribute two or more encoded spatial data streams to transmission antennas. The spatial spreading matrix has components (i) associated with each row of a row dimension having a number of rows equal to the number of the transmission antennas to be used to transmit the encoded spatial data streams and (ii) associated with each column of a column dimension having a number of columns equal to the number of the encoded spatial data streams to be transmitted. Additionally, the spatial spreading matrix satisfies one or more of the following two constraints: (1) the ratio of squared norms of the sum of the components of a row, for different rows of the spatial spreading matrix, is equal to a first constant sequence, and (2) the ratio of squared norms of the sum of a symbol Sl to be transmitted, when the symbol Sl is equal to 1 or −1, multiplied by each of the components of a row, for different rows of the spatial spreading matrix, is equal to a second constant sequence. | 09-16-2010 |
| 20100232483 | Calibration Correction for Implicit Beamforming in a Wireless MIMO Communication System - A first packet is transmitted via a forward channel corresponding to a signal direction from a first transceiver device to a second transceiver device, wherein the first packet includes a request to initiate calibration. A partial dimensional description of a reverse channel is determined based on the reception of a second packet received from the second transceiver device, wherein the second packet includes training information of spatial dimensions used for the transmission of the second packet but does not include training information for all available spatial dimensions of a reverse channel. A correction matrix is developed from the partial dimensional description of the reverse channel and a description of the forward channel, and the correction matrix and a steering matrix is used to process signals to be transmitted via the forward channel. | 09-16-2010 |
| 20100248635 | Sounding And Steering Protocols For Wireless Communications - The present disclosure includes systems, apparatuses, and techniques relating to wireless local area network devices. Systems, apparatuses, and techniques include communicating with multiple wireless communication devices to determine characteristics of spatial wireless channels, determining steering matrices based on one or more outputs of the communicating, and transmitting signals that concurrently provide data to the wireless communication devices via different spatial wireless channels. The signals can be spatially steered to the wireless communication devices based on the steering matrices. | 09-30-2010 |
| 20100260159 | PHYSICAL LAYER FRAME FORMAT FOR WLAN - In a method for generating a data unit for transmission via a communication channel, wherein the data unit conforms to a first communication protocol, a preamble of the data unit is generated. The preamble includes a first field having information that indicates a duration of the data unit, the first field being formatted such that the first field is decodable by a receiver device that conforms to a second communication protocol but does not conform to the first communication protocol to determine the duration of the data unit based on the first field. Additionally, the preamble is formatted such that a portion of the preamble is decodable by a receiver device that conforms to a third communication protocol but does not conform to the first communication protocol. Also, the preamble is formatted such that a receiver device that conforms to the first communication protocol can determine that the data unit conforms to the first communication protocol. A data portion of the data unit that conforms to the first communication protocol and does not conform to either (i) the second communication protocol or (ii) the third communication protocol is generated. | 10-14-2010 |
